Children and young people's body mass index measures derived from routine data sources: A national data linkage study in Wales

BACKGROUND

Routine monitoring of Body Mass Index (BMI) in general practice, and via national surveillance programmes, is essential for the identification, prevention, and management of unhealthy childhood weight. We examined and compared the presence and representativeness of children and young people's (CYPs) BMI recorded in two routinely collected administrative datasets: general practice electronic health records (GP-BMI) and the Child Measurement Programme for Wales (CMP-BMI), which measures height and weight in 4-5-year-old school children. We also assessed the feasibility of combining GP-BMI and CMP-BMI data for longitudinal analyses.

METHODS

We accessed de-identified population-level GP-BMI data for calendar years 2011 to 2019 for 246,817 CYP, and CMP-BMI measures for 222,772 CYP, held within the Secure Anonymised Information Linkage Databank. We examined the proportion of CYP in Wales with at least one GP-BMI record, its distribution by child socio-demographic characteristics, and trends over time. We compared GP-BMI and CMP-BMI distributions. We quantified the proportion of children with a CMP-BMI measure and a follow-up GP-BMI recorded at an older age and explored the representativeness of these measures.

RESULTS

We identified a GP-BMI record in 246,817 (41%) CYP, present in a higher proportion of females (54.2%), infants (20.7%) and adolescents. There was no difference in the deprivation profile of those with a GP-BMI measurement. 31,521 CYP with a CMP-BMI had at least one follow-up GP-BMI; those with a CMP-BMI considered underweight or very overweight were 87% and 70% more likely to have at least one follow-up GP-BMI record respectively compared to those with a healthy weight, as were males and CYP living in the most deprived areas of Wales.

CONCLUSIONS

Records of childhood weight status extracted from general practice are not representative of the population and are biased with respect to weight status. Linkage of information from the national programme to GP records has the potential to enhance discussions around healthy weight at the point of care but does not provide a representative estimate of population level weight trajectories, essential to provide insights into factors determining a healthy weight gain across the early life course. A second CMP measurement is required in Wales.

Motor Competence between Children with and without Additional Learning Needs: A Cross-Sectional Population-Level Study

The aim of this study was to examine associations in motor competence between children with additional learning needs (ALN) and typically developing children. This cross-sectional study involved a nationally representative cohort of 4555 children (48.98% boys; 11.35 ± 0.65 years) from sixty-five schools across Wales (UK). Demographic data were collected from schools, and children were assessed using the Dragon Challenge assessment of motor competence, which consists of nine tasks completed in a timed circuit. A multi-nominal multi-level model with random intercept was fitted to explore the proficiency between children with ALN and those without. In all nine motor competence tasks, typically developing children demonstrated higher levels of proficiency than their peers with ALN, with these associations evident after accounting for age, sex, ethnicity, and socioeconomic status. This study highlights motor competence inequalities at a population level and emphasises the need for policymakers, practitioners, and researchers to prioritise motor competence development, particularly for children with ALN.

Trajectories in chronic disease accrual and mortality across the lifespan in Wales, UK (2005-2019), by area deprivation profile: linked electronic health records cohort study on 965,905 individuals

Background

Understanding and quantifying the differences in disease development in different socioeconomic groups of people across the lifespan is important for planning healthcare and preventive services. The study aimed to measure chronic disease accrual, and examine the differences in time to individual morbidities, multimorbidity, and mortality between socioeconomic groups in Wales, UK.

Methods

Population-wide electronic linked cohort study, following Welsh residents for up to 20 years (2000-2019). Chronic disease diagnoses were obtained from general practice and hospitalisation records using the CALIBER disease phenotype register. Multi-state models were used to examine trajectories of accrual of 132 diseases and mortality, adjusted for sex, age and area-level deprivation. Restricted mean survival time was calculated to measure time spent free of chronic disease(s) or mortality between socioeconomic groups.

Findings

In total, 965,905 individuals aged 5-104 were included, from a possible 2.9 m individuals following a 5-year clearance period, with an average follow-up of 13.2 years (12.7 million person-years). Some 673,189 (69.7%) individuals developed at least one chronic disease or died within the study period. From ages 10 years upwards, the individuals living in the most deprived areas consistently experienced reduced time between health states, demonstrating accelerated transitions to first and subsequent morbidities and death compared to their demographic equivalent living in the least deprived areas. The largest difference were observed in 10 and 20 year old males developing multimorbidity (-0.45 years (99% CI: -0.45, -0.44)) and in 70 year old males dying after developing multimorbidity (-1.98 years (99% CI: -2.01, -1.95)).

Interpretation

This study adds to the existing literature on health inequalities by demonstrating that individuals living in more deprived areas consistently experience accelerated time to diagnosis of chronic disease and death across all ages, accounting for competing risks.

Funding

UK Medical Research Council, Health Data Research UK, and Administrative Data Research Wales.

Immunisation status of children receiving care and support in Wales: a national data linkage study

Background

In the UK, a robust childhood immunisation programme ensures children are offered protection against serious infections; identifying inequalities in vaccination coverage is essential. This is one of the first data linkage studies to examine coverage of primary, as well as pre-school booster and second dose of MMR vaccines, in children receiving support from social care services across Wales.

Methods

By accessing records held within the Secure Anonymised Information Linkage (SAIL) Databank, vaccination status of children receiving social care and support between April 2016 and March 2021 (n = 24,540) was ascertained. This was achieved through linkage of the Children Receiving Care and Support (CRCS) Census and National Community Child Health Database which holds vaccination records for all children in Wales registered for NHS care. This sample was split into three groups - those children who had never been recorded on the Child Protection Register (CPR) or as 'Looked After' but in CRCS (n = 12,480), children ever on the CPR (n = 6,225) and those ever recorded as 'Looked After' but who were never on the CPR (n = 5,840). The comparison group of children and young people (CYP) never receiving welfare support consisted of 624,905 children.

Results

Children receiving care or support were more likely to be up-to-date with all six vaccines (no recorded vaccines: 0.6-6.3%) compared to children in the comparison group (no recorded vaccines: 3-10.3%). However, of those who were vaccinated, they were less likely to be vaccinated in a timely manner; both early (5.2% vs. 22.2%; margin of error [ME] = 0.52, 95% CI [confidence interval] = -0.18 - -0.17, p < 0.001) and delayed vaccinations were more common (62.7% vs. 71.3%; ME = 0.58, 95% CI = 0.08-0.09, p < 0.001). Validation of the CRCS immunisation flag showed moderate levels of accuracy. Around 70% of immunisation flags were correct across all three groups.

Discussion

Findings suggest a positive association between receiving services under a care and support plan and being up-to-date with immunisations; children receiving support under a care and support plan were more likely to have experienced early or late vaccinations, demonstrating that there is still more inter-disciplinary co-ordination and planning needed to improve these outcomes. Thus, identifying inequalities in vaccination coverage is essential to target interventions and to prioritise geographic areas for catch-up.

Risk Factors Associated With Primary Care-Reported Domestic Violence for Women Involved in Family Law Care Proceedings: Data Linkage Observational Study

BACKGROUND

Domestic violence and abuse (DVA) has a detrimental impact on the health and well-being of children and families but is commonly underreported, with an estimated prevalence of 5.5% in England and Wales in 2020. DVA is more common in groups considered vulnerable, including those involved in public law family court proceedings; however, there is a lack of evidence regarding risk factors for DVA among those involved in the family justice system.

OBJECTIVE

This study examines risk factors for DVA within a cohort of mothers involved in public law family court proceedings in Wales and a matched general population comparison group.

METHODS

We linked family justice data from the Children and Family Court Advisory and Support Service (Cafcass Cymru [Wales]) to demographic and electronic health records within the Secure Anonymised Information Linkage (SAIL) Databank. We constructed 2 study cohorts: mothers involved in public law family court proceedings (2011-2019) and a general population group of mothers not involved in public law family court proceedings, matched on key demographics (age and deprivation). We used published clinical codes to identify mothers with exposure to DVA documented in their primary care records and who therefore reported DVA to their general practitioner. Multiple logistic regression analyses were used to examine risk factors for primary care-recorded DVA.

RESULTS

Mothers involved in public law family court proceedings were 8 times more likely to have had exposure to DVA documented in their primary care records than the general population group (adjusted odds ratio [AOR] 8.0, 95% CI 6.6-9.7). Within the cohort of mothers involved in public law family court proceedings, risk factors for DVA with the greatest effect sizes included living in sparsely populated areas (AOR 3.9, 95% CI 2.8-5.5), assault-related emergency department attendances (AOR 2.2, 95% CI 1.5-3.1), and mental health conditions (AOR 1.7, 95% CI 1.3-2.2). An 8-fold increased risk of DVA emphasizes increased vulnerabilities for individuals involved in public law family court proceedings.

CONCLUSIONS

Previously reported DVA risk factors do not necessarily apply to this group of women. The additional risk factors identified in this study could be considered for inclusion in national guidelines. The evidence that living in sparsely populated areas and assault-related emergency department attendances are associated with increased risk of DVA could be used to inform policy and practice interventions targeting prevention as well as tailored support services for those with exposure to DVA. However, further work should also explore other sources of DVA, such as that recorded in secondary health care, family, and criminal justice records, to understand the true scale of the problem.

COVID-19 vaccine uptake and effectiveness in adults aged 50 years and older in Wales UK: a 1.2m population data-linkage cohort approach

Vaccination programs against COVID-19 vary globally with estimates of vaccine effectiveness (VE) affected by vaccine type, schedule, strain, outcome, and recipient characteristics. This study assessed VE of BNT162b2 and ChAdOx1 vaccines against PCR positive SARS-CoV-2 infection, hospital admission, and death among adults aged 50 years and older in Wales, UK during the period 7 December 2020 to 18 July 2021, when Alpha, followed by Delta, were the predominant variants. We used individual-level linked routinely collected data within the Secure Anonymized Information Linkage (SAIL) Databank. Data were available for 1,262,689 adults aged 50 years and over; coverage of one dose of any COVID-19 vaccine in this population was 92.6%, with coverage of two doses 90.4%. VE against PCR positive infection at 28-days or more post first dose of any COVID-19 vaccine was 16.0% (95%CI 9.6-22.0), and 42.0% (95%CI 36.5-47.1) seven or more days after a second dose. VE against hospital admission was higher at 72.9% (95%CI 63.6-79.8) 28 days or more post vaccination with one dose of any vaccine type, and 84.9% (95%CI 78.2-89.5) at 7 or more days post two doses. VE for one dose against death was estimated to be 80.9% (95%CI 72.1-86.9). VE against PCR positive infection and hospital admission was higher for BNT162b2 compared to ChAdOx1. In conclusion, vaccine uptake has been high among adults in Wales and VE estimates are encouraging, with two doses providing considerable protection against severe outcomes. Continued roll-out of the vaccination programme within Wales, and globally, is crucial in our fight against COVID-19.

Built Environments And Child Health in WalEs and AuStralia (BEACHES): a study protocol

INTRODUCTION

Childhood obesity and physical inactivity are two of the most significant modifiable risk factors for the prevention of non-communicable diseases (NCDs). Yet, a third of children in Wales and Australia are overweight or obese, and only 20% of UK and Australian children are sufficiently active. The purpose of the Built Environments And Child Health in WalEs and AuStralia (BEACHES) study is to identify and understand how complex and interacting factors in the built environment influence modifiable risk factors for NCDs across childhood.

METHODS AND ANALYSIS

This is an observational study using data from five established cohorts from Wales and Australia: (1) Wales Electronic Cohort for Children; (2) Millennium Cohort Study; (3) PLAY Spaces and Environments for Children's Physical Activity study; (4) The ORIGINS Project; and (5) Growing Up in Australia: the Longitudinal Study of Australian Children. The study will incorporate a comprehensive suite of longitudinal quantitative data (surveys, anthropometry, accelerometry, and Geographic Information Systems data) to understand how the built environment influences children's modifiable risk factors for NCDs (body mass index, physical activity, sedentary behaviour and diet).

ETHICS AND DISSEMINATION

This study has received the following approvals: University of Western Australia Human Research Ethics Committee (2020/ET000353), Ramsay Human Research Ethics Committee (under review) and Swansea University Information Governance Review Panel (Project ID: 1001). Findings will be reported to the following: (1) funding bodies, research institutes and hospitals supporting the BEACHES project; (2) parents and children; (3) school management teams; (4) existing and new industry partner networks; (5) federal, state and local governments to inform policy; as well as (6) presented at local, national and international conferences; and (7) disseminated by peer-reviewed publications.

Pre-COVID-19 pandemic health-related behaviours in children (2018-2020) and association with being tested for SARS-CoV-2 and testing positive for SARS-CoV-2 (2020-2021): a retrospective cohort study using survey data linked with routine health data in Wales, UK

OBJECTIVES

Examine if pre-COVID-19 pandemic (prior March 2020) health-related behaviours during primary school are associated with (1) being tested for SARS-CoV-2 and (2) testing positive between 1 March 2020 and 31 August 2021.

DESIGN

Retrospective cohort study using an online cohort survey (January 2018 to February 2020) linked with routine PCR SARS-CoV-2 test results.

SETTING

Children attending primary schools in Wales (2018-2020), UK, who were part of the Health and Attainment of Pupils in a Primary Education Network (HAPPEN)_school network.

PARTICIPANTS

Complete linked records of eligible participants were obtained for n=7062 individuals. 39.1% (n=2764) were tested (age 10.6±0.9; 48.9% girls) and 8.1% (n=569) tested positive for SARS-CoV-2 (age 10.6±1.0; 54.5% girls).

MAIN OUTCOME MEASURES

Logistic regression of health-related behaviours and demographics were used to determine the ORs of factors associated with (1) being tested for SARS-CoV-2 and (2) testing positive for SARS-CoV-2.

RESULTS

Consuming sugary snacks (1-2 days/week OR=1.24, 95% CI 1.04 to 1.49; 5-6 days/week OR=1.31, 95% CI 1.07 to 1.61; reference 0 days), can swim 25 m (OR=1.21, 95% CI 1.06 to 1.39) and age (OR=1.25, 95% CI 1.16 to 1.35) were associated with an increased likelihood of being tested for SARS-CoV-2. Eating breakfast (OR=1.52, 95% CI 1.01 to 2.27), weekly physical activity ≥60 min (1-2 days OR=1.69, 95% CI 1.04 to 2.74; 3-4 days OR=1.76, 95% CI 1.10 to 2.82; reference 0 days), out-of-school club participation (OR=1.06, 95% CI 1.02 to 1.10), can ride a bike (OR=1.39, 95% CI 1.00 to 1.93), age (OR=1.16, 95% CI 1.05 to 1.28) and girls (OR=1.21, 95% CI 1.00 to 1.46) were associated with an increased likelihood of testing positive for SARS-CoV-2. Living in least deprived areas (quintile 4 OR=0.64, 95% CI 0.46 to 0.90; quintile 5 OR=0.64, 95% CI 0.46 to 0.89) compared with the most deprived (quintile 1) was associated with a decreased likelihood.

CONCLUSIONS

Associations may be related to parental health literacy and monitoring behaviours. Physically active behaviours may include coparticipation with others and exposure to SARS-CoV-2. A risk-versus-benefit approach must be considered in relation to promoting these health behaviours, given the importance of health-related behaviours such as childhood physical activity for development.

Linking cohort data and Welsh routine health records to investigate children at risk of delayed primary vaccination

BACKGROUND

Delayed primary vaccination is one of the strongest predictors of subsequent incomplete immunisation. Identifying children at risk of such delay may enable targeting of interventions, thus decreasing vaccine-preventable illness.

OBJECTIVES

To explore socio-demographic factors associated with delayed receipt of the Diphtheria, Tetanus and Pertussis (DTP) vaccine.

METHODS

We included 1,782 children, born between 2000 and 2001, participating in the Millennium Cohort Study (MCS) and resident in Wales, whose parents gave consent for linkage to National Community Child Health Database records at the age seven years contact. We examined child, maternal, family and area characteristics associated with delayed receipt of the first dose of the DTP vaccine.

RESULTS

98.6% received the first dose of DTP. The majority, 79.6% (n = 1,429) received it on time (between 8 and 12 weeks of age), 14.2% (n = 251) received it early (prior to 8 weeks of age) and 4.8% (n = 79) were delayed (after 12 weeks of age); 1.4% (n = 23) never received it. Delayed primary vaccination was more likely among children with older natural siblings (risk ratio 3.82, 95% confidence interval (1.97, 7.38)), children admitted to special/intensive care (3.15, (1.65, 5.99)), those whose birth weight was > 4Kg (2.02, (1.09, 3.73)) and boys (1.53, (1.01, 2.31)). There was a reduced risk of delayed vaccination with increasing maternal age (0.73, (0.53, 1.00) per 5 year increase) and for babies born to graduate mothers (0.27, (0.08, 0.90)).

CONCLUSIONS

Although the majority of infants were vaccinated in a timely manner, identification of infants at increased risk of early or delayed vaccination will enable targeting of interventions to facilitate timely immunisation. This is to our knowledge the first study exploring individual level socio-demographic factors associated with delayed primary vaccination in the UK and demonstrates the benefits of linking cohort data to routinely-collected child health data.

Early-life respiratory tract infections and the risk of school-age lower lung function and asthma: a meta-analysis of 150 000 European children

Background

Early-life respiratory tract infections might affect chronic obstructive respiratory diseases, but conclusive studies from general populations are lacking. Our objective was to examine if children with early-life respiratory tract infections had increased risks of lower lung function and asthma at school age.

Methods

We used individual participant data of 150 090 children primarily from the EU Child Cohort Network to examine the associations of upper and lower respiratory tract infections from age 6 months to 5 years with forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), FEV₁/FVC, forced expiratory flow at 75% of FVC (FEF_75%) and asthma at a median (range) age of 7 (4–15) years.

Results

Children with early-life lower, not upper, respiratory tract infections had a lower school-age FEV₁, FEV₁/FVC and FEF_75% (z-score range: −0.09 (95% CI −0.14– −0.04) to −0.30 (95% CI −0.36– −0.24)). Children with early-life lower respiratory tract infections had a higher increased risk of school-age asthma than those with upper respiratory tract infections (OR range: 2.10 (95% CI 1.98–2.22) to 6.30 (95% CI 5.64–7.04) and 1.25 (95% CI 1.18–1.32) to 1.55 (95% CI 1.47–1.65), respectively). Adjustment for preceding respiratory tract infections slightly decreased the strength of the effects. Observed associations were similar for those with and without early-life wheezing as a proxy for early-life asthma.

Conclusions

Our findings suggest that early-life respiratory tract infections affect development of chronic obstructive respiratory diseases in later life, with the strongest effects for lower respiratory tract infections.

This meta-analysis of 150 000 children suggests that mostly lower respiratory tract infections are associated with an increased risk of asthma and lower lung function. This is independent from preceding respiratory tract infections or early-life asthma.https://bit.ly/3weE62I

A Socioecological Perspective of How Physical Activity and Sedentary Behaviour at Home Changed during the First Lockdown of COVID-19 Restrictions: The HomeSPACE Project

The COVID-19 pandemic forced school closures, resulting in home schooling, more time spent at home and fewer opportunities for physical activity (PA). This study explored factors influencing PA and sedentary behaviours (SB) within the home environment during the first lockdown, starting in March 2020. Twenty semi-structured interviews (20 parents and 23 children, 12 years ± 1.25) were conducted. Data were coded using thematic analysis on NVivo© and concepts from McLeroy’s socioecological model for health promotion were used to analyse the data. Findings indicate that children’s PA and SB at home were influenced by: (i) individual-level factors (e.g., gender, competence, attitudes and motivation); (ii) interpersonal-level factors (e.g., siblings, parents, pets, friends and coaches); (iii) organisation-level factors (e.g., school, clubs and societies), (iv) community-level factors (e.g., home and local environment, access to facilities, social norms, time constraints and home equipment), and (v) policy-level factors (e.g., lockdown restrictions). Stay-at-home mandates resulted in perceived reductions in PA and increases in SB within the home; however, this provided alternative positive opportunities for families, including more time to spend together and exploring green and blue spaces in the local area.

A population level study into health vulnerabilities of mothers and fathers involved in public law care proceedings in Wales, UK between 2011 and 2019

IntroductionUnder section 31 of the Children Act 1989, public law care proceedings can be issued if there is concern a child is subject to, or at risk of significant harm, which can lead to removal of a child from parents. Appropriate and effective health and social support are required to potentially prevent some of the need for these proceedings. More comprehensive evidence of the health needs and vulnerabilities of parents will enable enhanced response from family courts and integrated other services. ObjectiveTo examine health vulnerabilities of parents involved in care proceedings in the two-year period prior to involvement. MethodsFamily court data provided by Cafcass Cymru were linked to population-based health records held within the Secure Anonymised Information Linkage Databank. Linked data were available for 8,821 parents of children involved in care proceedings between 2011 and 2019. Findings were benchmarked with reference to a comparison group of parents matched on sex, age, and deprivation (n = 32,006), not subject to care proceedings. Demographic characteristics, overall health service use, and health profiles of parents were examined. Descriptive and statistical tests of independence were used. ResultsNearly half of cohort parents (47.6%) resided in the most deprived quintile. They had higher levels of healthcare use compared to the comparison group across multiple healthcare settings, with the most pronounced differences for emergency department attendances (59.3% vs 37.0%). Health conditions with the largest variation between groups were related to mental health (43.6% vs 16.0%), substance use (19.4% vs 1.6%) and injuries (41.5% vs 23.6%). ConclusionThis study highlights the heightened socioeconomic and health vulnerabilities of parents who experience care proceedings concerning a child. Better understanding of the needs and vulnerabilities of this population may provide opportunities to improve a range of support and preventative interventions that respond to crises in the community.

A population level study into health vulnerabilities of mothers and fathers involved in public law care proceedings in Wales, UK between 2011 and 2019

Introduction

Under section 31 of the Children Act 1989, public law care proceedings can be issued if there is concern a child is subject to, or at risk of significant harm, which can lead to removal of a child from parents. Appropriate and effective health and social support are required to potentially prevent some of the need for these proceedings. More comprehensive evidence of the health needs and vulnerabilities of parents will enable enhanced response from family courts and integrated other services.

Objective

To examine health vulnerabilities of parents involved in care proceedings in the two-year period prior to involvement.

Methods

Family court data provided by Cafcass Cymru were linked to population-based health records held within the Secure Anonymised Information Linkage Databank. Linked data were available for 8,821 parents of children involved in care proceedings between 2011 and 2019. Findings were benchmarked with reference to a comparison group of parents matched on sex, age, and deprivation (n = 32,006), not subject to care proceedings. Demographic characteristics, overall health service use, and health profiles of parents were examined. Descriptive and statistical tests of independence were used.

Results

Nearly half of cohort parents (47.6%) resided in the most deprived quintile. They had higher levels of healthcare use compared to the comparison group across multiple healthcare settings, with the most pronounced differences for emergency department attendances (59.3% vs 37.0%). Health conditions with the largest variation between groups were related to mental health (43.6% vs 16.0%), substance use (19.4% vs 1.6%) and injuries (41.5% vs 23.6%).

Conclusion

This study highlights the heightened socioeconomic and health vulnerabilities of parents who experience care proceedings concerning a child. Better understanding of the needs and vulnerabilities of this population may provide opportunities to improve a range of support and preventative interventions that respond to crises in the community.

COVID-19 vaccine uptake, effectiveness, and waning in 82,959 health care workers: A national prospective cohort study in Wales

BACKGROUND

While population estimates suggest high vaccine effectiveness against SARS-CoV-2 infection, the protection for health care workers, who are at higher risk of SARS-CoV-2 exposure, is less understood.

METHODS

We conducted a national cohort study of health care workers in Wales (UK) from 7 December 2020 to 30 September 2021. We examined uptake of any COVID-19 vaccine, and the effectiveness of BNT162b2 mRNA (Pfizer-BioNTech) against polymerase chain reaction (PCR) confirmed SARS-CoV-2 infection. We used linked and routinely collected national-scale data within the SAIL Databank. Data were available on 82,959 health care workers in Wales, with exposure extending to 26 weeks after second doses.

RESULTS

Overall vaccine uptake was high (90%), with most health care workers receiving theBNT162b2 vaccine (79%). Vaccine uptake differed by age, staff role, socioeconomic status; those aged 50-59 and 60+ years old were 1.6 times more likely to get vaccinated than those aged 16-29. Medical and dental staff, and Allied Health Practitioners were 1.5 and 1.1 times more likely to get vaccinated, compared to nursing and midwifery staff. The effectiveness of the BNT162b2 vaccine was found to be strong and consistent across the characteristics considered; 52% three to six weeks after first dose, 86% from two weeks after second dose, though this declined to 53% from 22 weeks after the second dose.

CONCLUSIONS

With some variation in rate of uptake, those who were vaccinated had a reduced risk of PCR-confirmed SARS-CoV-2 infection, compared to those unvaccinated. Second dose has provided stronger protection for longer than first dose but our study is consistent with waning from seven weeks onwards.

Investigating the uptake, effectiveness and safety of COVID-19 vaccines: protocol for an observational study using linked UK national data

INTRODUCTION

The novel coronavirus SARS-CoV-2, which emerged in December 2019, has caused millions of deaths and severe illness worldwide. Numerous vaccines are currently under development of which a few have now been authorised for population-level administration by several countries. As of 20 September 2021, over 48 million people have received their first vaccine dose and over 44 million people have received their second vaccine dose across the UK. We aim to assess the uptake rates, effectiveness, and safety of all currently approved COVID-19 vaccines in the UK.

METHODS AND ANALYSIS

We will use prospective cohort study designs to assess vaccine uptake, effectiveness and safety against clinical outcomes and deaths. Test-negative case-control study design will be used to assess vaccine effectiveness (VE) against laboratory confirmed SARS-CoV-2 infection. Self-controlled case series and retrospective cohort study designs will be carried out to assess vaccine safety against mild-to-moderate and severe adverse events, respectively. Individual-level pseudonymised data from primary care, secondary care, laboratory test and death records will be linked and analysed in secure research environments in each UK nation. Univariate and multivariate logistic regression models will be carried out to estimate vaccine uptake levels in relation to various population characteristics. VE estimates against laboratory confirmed SARS-CoV-2 infection will be generated using a generalised additive logistic model. Time-dependent Cox models will be used to estimate the VE against clinical outcomes and deaths. The safety of the vaccines will be assessed using logistic regression models with an offset for the length of the risk period. Where possible, data will be meta-analysed across the UK nations.

ETHICS AND DISSEMINATION

We obtained approvals from the National Research Ethics Service Committee, Southeast Scotland 02 (12/SS/0201), the Secure Anonymised Information Linkage independent Information Governance Review Panel project number 0911. Concerning English data, University of Oxford is compliant with the General Data Protection Regulation and the National Health Service (NHS) Digital Data Security and Protection Policy. This is an approved study (Integrated Research Application ID 301740, Health Research Authority (HRA) Research Ethics Committee 21/HRA/2786). The Oxford-Royal College of General Practitioners Clinical Informatics Digital Hub meets NHS Digital's Data Security and Protection Toolkit requirements. In Northern Ireland, the project was approved by the Honest Broker Governance Board, project number 0064. Findings will be made available to national policy-makers, presented at conferences and published in peer-reviewed journals.

Associations between swimming & cycling abilities and fitness in 9-11 year old boys and girls

The associations between swimming and cycling abilities and fitness levels in 9-11-year-old children were examined. A cross-sectional study involving 2258 children (50.7% boys; aged 10.52 ± 0.6 years) from 33 schools across Wales, participated in Swan/BridgeLinx health, fitness, and lifestyle programmes between 2013-2019. Health and fitness data were collected; namely body composition, cardiorespiratory fitness, muscular strength, flexibility, power, and speed using standardised measures. Children completed an online survey collecting data on swimming and cycling abilities and sports club attendance. Multivariate multilevel regressions were used to examine the associations between measures. The ability to swim and cycle was significantly (p < 0.05) associated with all components of fitness when accounting for age, body mass index (BMI), deprivation, gender, and sports club attendance. Boys outperformed girls with significant interactions between swimming, cycling and cardiorespiratory fitness for gender by swim (p = 0.001) and gender by cycle (p = 0.015). The gender by cycle interaction significantly predicted grip strength and power (p < 0.05). Swimming and cycling are important "milestones" in the journey of motor development and are associated with higher levels of fitness. These activities should be promoted to allow for an optimal development of motor skills, fitness, and health.

Are individual and social factors specific to the home associated with children's behaviour and physical environment at home

This study used linear regression analyses to investigate the influence of parent-reported home-specific social and individual factors on: (i) 235 children's home-based objectively measured overall sitting time, breaks in sitting, and PA, and; (ii) the home physical environment via an audit. Parental importance assigned to active play for children was positively associated with PA equipment (accessibility and availability), as well as light physical activity (LPA) and sitting breaks on both weekdays and weekend days. Parental preference for being active at home and limits on screen-time were associated with less household media equipment and portable media equipment, respectively. Greater parental importance placed on playing electronic games/using computers for fun was associated with less LPA and more sitting on weekdays. Further, children who preferred being sedentary sat more and engaged in less moderate-vigorous physical activity (MVPA) on weekdays. Parental and child preferences and priorities, as well as parental rules for activity at home, were associated with children's home-based sitting and PA, especially on weekdays. Such factors were also associated with the physical environment in the expected directions. The findings suggest interventions need to target social and individual factors, alongside adapting the physical environment to create homes more promotive of physical activity.

Deriving household composition using population-scale electronic health record data-A reproducible methodology

BACKGROUND

Physical housing and household composition have an important role in the lives of individuals and drive health and social outcomes, and inequalities. Most methods to understand housing composition are based on survey or census data, and there is currently no reproducible methodology for creating population-level household composition measures using linked administrative data.

METHODS

Using existing, and more recent enhancements to the address-data linkage methods in the SAIL Databank using Residential Anonymised Linking Fields we linked individuals to properties using the anonymised Welsh Demographic Service data in the SAIL Databank. We defined households, household size, and household composition measures based on adult to child relationships, and age differences between residents to create relative age measures.

RESULTS

Two relative age-based algorithms were developed and returned similar results when applied to population and household-level data, describing household composition for 3.1 million individuals within 1.2 million households in Wales. Developed methods describe binary, and count level generational household composition measures.

CONCLUSIONS

Improved residential anonymised linkage field methods in SAIL have led to improved property-level data linkage, allowing the design and application of household composition measures that assign individuals to shared residences and allow the description of household composition across Wales. The reproducible methods create longitudinal, household-level composition measures at a population-level using linked administrative data. Such measures are important to help understand more detail about an individual's home and area environment and how that may affect the health and wellbeing of the individual, other residents, and potentially into the wider community.

The Potential of Research Drawing on Clinical Free Text to Bring Benefits to Patients in the United Kingdom: A Systematic Review of the Literature

Background: The analysis of clinical free text from patient records for research has potential to contribute to the medical evidence base but access to clinical free text is frequently denied by data custodians who perceive that the privacy risks of data-sharing are too high. Engagement activities with patients and regulators, where views on the sharing of clinical free text data for research have been discussed, have identified that stakeholders would like to understand the potential clinical benefits that could be achieved if access to free text for clinical research were improved. We aimed to systematically review all UK research studies which used clinical free text and report direct or potential benefits to patients, synthesizing possible benefits into an easy to communicate taxonomy for public engagement and policy discussions. Methods: We conducted a systematic search for articles which reported primary research using clinical free text, drawn from UK health record databases, which reported a benefit or potential benefit for patients, actionable in a clinical environment or health service, and not solely methods development or data quality improvement. We screened eligible papers and thematically analyzed information about clinical benefits reported in the paper to create a taxonomy of benefits. Results: We identified 43 papers and derived five themes of benefits: health-care quality or services improvement, observational risk factor-outcome research, drug prescribing safety, case-finding for clinical trials, and development of clinical decision support. Five papers compared study quality with and without free text and found an improvement of accuracy when free text was included in analytical models. Conclusions: Findings will help stakeholders weigh the potential benefits of free text research against perceived risks to patient privacy. The taxonomy can be used to aid public and policy discussions, and identified studies could form a public-facing repository which will help the health-care text analysis research community better communicate the impact of their work.

Maternal health, pregnancy and birth outcomes for women involved in care proceedings in Wales: a linked data study

BACKGROUND

Under the Children Act 1989, local authorities in Wales, UK, can issue care proceedings if they are concerned about the welfare of a child, which can lead to removal of a child from parents. For mothers at risk of child removal, timely intervention during pregnancy may avert the need for this and improve maternal/fetal health; however, little is known about this specific population during the antenatal period. The study examined maternity characteristics of mothers whose infants were subject to care proceedings, with the aim of informing preventative interventions targeted at high risk mothers.

METHODS

Anonymised administrative data from Cafcass Cymru, who provide child-focused advice and support for family court proceedings in Wales, were linked to population-based maternity and health records held within the Secure Anonymised Information Linkage Databank. Linked data were available for 1111 birth mothers of infants involved in care proceedings between 2015 and 2018. Findings were benchmarked with reference to an age-deprivation-matched comparison group (n = 23,414), not subject to care proceedings but accessing maternity services during this period. Demographic characteristics, maternal health, reproductive history, interaction with midwifery services, and pregnancy and birth outcomes were examined. Descriptive and statistical tests of independence were used.

RESULTS

Half of the women in the cohort (49.4%) resided in the most deprived areas. They were more likely to be younger at entry to motherhood (63.5% < 21 years-of-age compared to 42.7% in the comparison group), to have mental health (28.6% compared to 8.2%) and substance use issues (10.4% compared to 0.6%) and to smoke (62.7% compared to 24.8%) during pregnancy. The majority first engaged with maternity services within their first trimester of pregnancy (63.5% compared to 84.4%). Babies were more likely to be born preterm (14.2% compared to 6.7%) and, for full-term babies, to have low birthweights (8.0% compared to 2.8%).

CONCLUSION

This novel linkage study highlights multiple vulnerabilities experienced by pregnant mothers who have experienced care proceedings concerning an infant. Policy and practice colleagues require a clearer picture of women's needs if child protection and health services are to offer effective services which prevent the need for family court proceedings and infant removal.

Toward the Development of Data Governance Standards for Using Clinical Free-Text Data in Health Research: Position Paper

BACKGROUND

Clinical free-text data (eg, outpatient letters or nursing notes) represent a vast, untapped source of rich information that, if more accessible for research, would clarify and supplement information coded in structured data fields. Data usually need to be deidentified or anonymized before they can be reused for research, but there is a lack of established guidelines to govern effective deidentification and use of free-text information and avoid damaging data utility as a by-product.

OBJECTIVE

This study aimed to develop recommendations for the creation of data governance standards to integrate with existing frameworks for personal data use, to enable free-text data to be used safely for research for patient and public benefit.

METHODS

We outlined data protection legislation and regulations relating to the United Kingdom for context and conducted a rapid literature review and UK-based case studies to explore data governance models used in working with free-text data. We also engaged with stakeholders, including text-mining researchers and the general public, to explore perceived barriers and solutions in working with clinical free-text.

RESULTS

We proposed a set of recommendations, including the need for authoritative guidance on data governance for the reuse of free-text data, to ensure public transparency in data flows and uses, to treat deidentified free-text data as potentially identifiable with use limited to accredited data safe havens, and to commit to a culture of continuous improvement to understand the relationships between the efficacy of deidentification and reidentification risks, so this can be communicated to all stakeholders.

CONCLUSIONS

By drawing together the findings of a combination of activities, we present a position paper to contribute to the development of data governance standards for the reuse of clinical free-text data for secondary purposes. While working in accordance with existing data governance frameworks, there is a need for further work to take forward the recommendations we have proposed, with commitment and investment, to assure and expand the safe reuse of clinical free-text data for public benefit.

Data Resource: population level family justice administrative data with opportunities for data linkage

INTRODUCTION

Although there has been considerable progress in the use of administrative data for applied health research, the family justice field lags behind. Better use of administrative data are essential to enhance understanding of how the family justice system is working, as well as the characteristics of, and outcomes for, children and families. The Family Justice Data Partnership (FJDP) supports this aim through analyses of core family justice and linked datasets in the SAIL Databank (Secure Anonymised Information Linkage). Cafcass Cymru provide expert advice for children involved in family court proceedings in Wales, ensuring decisions are made in the best interests of the child. We provide an overview of Cafcass Cymru data. We also describe and illustrate linkage to administrative datasets within SAIL.

METHODS

Cafcass Cymru data was transferred to SAIL using a standardised approach to provide de-identified data with Anonymised Linking Fields (ALF) for successfully matched records. Three cohorts were created: all individuals involved in family court applications; all individuals with an ALF allowing subsequent health data linkage; and all individuals with a Residential Anonymised Linking Field (RALF) enabling area-level deprivation analysis.

RESULTS

Cafcass Cymru application data are available for child protection matters (public law, range 2011-2019, n=12,745), and child arrangement disputes (private law, range 2005-2019, n=52,023). An 80% data linkage match rate was achieved. 40% had hospital admissions within two years pre or post application; 54% had emergency department attendances and 61% had outpatient appointments. Individuals were more likely to reside in deprived areas regardless of law type.

CONCLUSION

Cafcass Cymru data can be accessed through the SAIL Databank. The FJDP will continue to enhance research opportunities for all to better understand the family justice system, and outcomes for those involved, such as health and wellbeing for children and family members.

Educational differentials in key domains of physical activity by ethnicity, age and sex: a cross-sectional study of over 40 000 participants in the UK household longitudinal study (2013-2015)

OBJECTIVES

To assess whether educational differentials in three key physical activity (PA) domains vary by age, sex and ethnicity.

DESIGN

National cross-sectional survey.

SETTING

UK.

PARTICIPANTS

Altogether 40 270 participants, aged 20 years and over, from the UK Household Longitudinal Study with information on education, PA and demographics collected in 2013-2015.

OUTCOME MEASURES

Participation in active travel (AT), occupational activity (OA) and leisure time physical activity (LTPA) at the time of assessment.

RESULTS

Lower educational attainment was associated with higher AT and OA, but lower weekly LTPA activity; these associations were modified by sex, ethnicity and age. Education-related differences in AT were larger for women-the difference in predicted probability of activity between the highest and the lowest education groups was -10% in women (95% CI: -11.9% to 7.9%) and -3% in men (-4.8% to -0.4%). Education-related differences in OA were larger among men -35% (-36.9% to -32.4%) than women -17% (-19.4% to -15.0%). Finally, education-related differences in moderate-to-vigorous LTPA varied by ethnicity; for example, differences were 17% (16.2% to 18.7%) for white individuals compared with 6% (0.6% to 11.6%) for black individuals.

CONCLUSIONS

Educational differences in PA vary by domain and are modified by age, sex and ethnicity. A better understanding of physically inactive subgroups may aid development of interventions to both increase activity levels and reduce health inequalities.

Could Greater Physical Activity Reduce Population Prevalence and Socioeconomic Inequalities in Children's Mental Health Problems? A Policy Simulation

BACKGROUND

One in four children 5-16 years (y) of age shows signs of mental health problems in the United Kingdom; risk is higher in economically disadvantaged groups. Greater physical activity is associated with lower risk of internalizing problems such as depression and anxiety. We simulated the potential impact of population-wide physical activity interventions on overall prevalence of internalizing problems, and by family income. Interventions were based on the World Health Organization (WHO) children's target of 60 minutes (min) of moderate-to-vigorous physical activity per day and trial evidence.

METHODS

Data were from the UK Millennium Cohort Study, a population-representative cohort of children born in 2000-2002. Household income (5 y) was the exposure; internalizing problems (outcome) were measured using the Strengths and Difficulties Questionnaire (11 y). Of 18,296 singletons, 6,497 had accelerometer physical activity data (mediator, manipulated to simulate interventions) at 7 y. We predicted probabilities of outcome according to exposure in marginal structural models, weighted for attrition and confounding, and adjusted for observed mediator. We then re-estimated probabilities in different physical activity intervention scenarios, assessing income inequalities in internalizing problems with risk ratios (RRs) and differences (RDs) according to income quintile.

RESULTS

Simulating universal achievement of the WHO target led to little change in prevalence (10% [95% CI = 8%, 12%]) and socioeconomic inequalities in internalizing problems; RR: 2.2 (1.1, 3.4); RD: 8% [5%,13%]). More modest increases in physical activity achieved weaker results.

CONCLUSIONS

Our simulations suggest that large increases in moderate-to-vigorous physical activity in the United Kingdom would have little effect on prevalence and inequalities in child mental health problems.

Physical activity among children with asthma: Cross-sectional analysis in the UK millennium cohort

BACKGROUND

Although beneficial for health and well-being, most children do not achieve recommended levels of physical activity. Evidence for children with asthma is mixed, with symptom severity rarely considered. This paper aimed to address this gap.

METHODS

We analyzed cross-sectional associations between physical activity and parent-reported asthma symptoms and severity for 6497 UK Millennium Cohort Study 7-year-old participants (3321, [49%] girls). Primary outcomes were daily moderate-to-vigorous physical activity (MVPA, minutes) and proportion of children achieving recommended minimum daily levels of 60 minutes of MVPA. Daily steps, sedentary time, and total activity counts per minute (cpm) were recorded, as were parent-reported asthma symptoms, medications, and recent hospital admissions. Associations were investigated using quantile (continuous outcomes) and Poisson (binary outcomes) regression, adjusting for demographic, socioeconomic, health, and environmental factors.

RESULTS

Neither asthma status nor severity was associated with MVPA; children recently hospitalized for asthma were less likely to achieve recommended daily MVPA (risk ratio [95% confidence interval [CI]]: 0.67 [0.44, 1.03]). Recent wheeze, current asthma, and severe asthma symptoms were associated with fewer sedentary hours (difference in medians [95% CI]: -0.18 [-0.27, -0.08]; -0.14 [-0.24, -0.05]; -0.15, [-0.28, -0.02], respectively) and hospital admission with lower total activity (-48 cpm [-68, -28]).

CONCLUSION

Children with asthma are as physically active as their asthma-free counterparts, while those recently hospitalized for asthma are less active. Qualitative studies are needed to understand the perceptions of children and families about physical activity following hospital admission and to inform support and advice needed to maintain active lifestyles for children with asthma.

Are children with clinical obesity at increased risk of inpatient hospital admissions? An analysis using linked electronic health records in the UK millennium cohort study

BACKGROUND

Few studies have examined health service utilization of children with overweight or obesity by using linked electronic health records (EHRs).

OBJECTIVE/METHODS

We analysed EHRs from 3269 children (1678 boys; 51.3% [weighted]) participating in the Millennium Cohort Study, living in Wales or Scotland at age seven whose parents consented to record linkage. We used height and weight measurements at age five to categorize children as obese (>98th centile) or overweight (>91st centile) (UK1990 clinical reference standards) and linked to hospital admissions, up to age 14 years, in the Patient Episode Database for Wales and Scottish Morbidity Records. Negative binomial regression models compared rates of inpatient admissions by weight status at age five.

RESULTS

At age five, 11.5% and 6.7% of children were overweight or obese, respectively; 1221 (38%) children were subsequently admitted to hospital at least once. Admissions were not increased among children with overweight or obesity (adjusted rate ratio [RR], 95% confidence interval [CI]: 0.87, 0.68-1.10 and 1.16, 0.87-1.54, respectively).

CONCLUSIONS

In this nationally representative cohort of children in Wales and Scotland, those with overweight or obesity at entry to primary school did not have increased rates of hospital admissions in later childhood and early adolescence.

Analysis of factors associated with changing general practice in the first 14 years of life in Wales using linked cohort and primary care records: implications for using primary care databanks for life course research

IntroductionPrimary care electronic health records (pcEHRs) are a valuable resource for life course research, however loss to follow up due to changing practices has received little attention. We investigated factors associated with changes in registration and record continuity in the Secure Anonymised Information Linkage (SAIL) databank, with ~80% practice coverage. Objectives and ApproachWe analysed linked pcEHRs for 1834 (882 girls) Millennium Cohort Study (MCS) participants, resident in Wales and with parental consent to health record linkage at the age seven MCS interview. We studied time from first to next general practice (GP) registration in Wales by fitting Cox proportional hazards models, and estimated mutually-adjusted hazard ratios (aHRs) for the following factors: child (sex, ethnicity, mode of delivery, gestation, birthweight, neonatal illness, wheeze, longstanding illness); maternal (age, education, lone parent status); household (income, housing tenure, residential mobility, urban/rural residence); GP type (SAIL-contributing/-non-contributing). Analyses were weighted for survey design (Stata: Release 15; StataCorp LP). ResultsThere were 3065 Welsh GP registrations for 1834 children. By age 5 years, 25% of children changed GP at least once, with 1070 (58.3%), 477 (26.0%) and 287 (15.7%) registered with 1, 2, 3+ GPs respectively up to 14 years of age. Children with older mothers (aHRs; 95% CI: 0.96; 0.95, 0.98; per year) or those residing in rural areas (0.75;0.56,0.99) were less likely, and those whose first registration was not with a SAIL contributing GP (2.16;1.60,2.93), whose mothers had no educational qualifications (1.40;1.15,1.71), or had recently changed address (1.62;1.21,2.16) more likely, to change GP. 305 (16.6%) children had never registered with a SAIL-contributing GP. Of 403 children initially registered with a SAIL contributing GP who then changed GP, 66.7% re-registered with a SAIL contributing GP. Conclusion/ImplicationsGeographically contiguous primary care databanks, such as the SAIL databank, enable a high proportion of children to be reliably followed over time despite changing GP. Similar analyses of databases based on geographically disparate volunteer GPs are needed to quality assure their suitability for life course epidemiology research.

Analysis of factors associated with changing general practice in the first 14 years of life in Wales using linked cohort and primary care records: implications for using primary care databanks for life-course research

Background Databanks of primary care electronic health records (pcEHRs) are a valuable resource for life course research, however loss to follow up due to changing general practice has received little attention. ObjectiveWe investigated factors associated with changing general practice (GP) in early life and continuity of participation in the Secure Anonymised Information Linkage (SAIL) databank, to which approximately 80% of Welsh practices contribute. MethodsWe analysed linked pcEHRs for 1834 (882 girls) Millennium Cohort Study participants, resident in Wales, with consent to health record linkage. We studied time from first to next practice registration using Cox proportional hazards models, and estimated mutually-adjusted hazard ratios (aHRs) for child, household and practice factors. FindingsThere were 3065 Welsh GP registrations for 1834 children. By age 5 years, 25% changed practice at least once, with 1070 (58.3%), 477 (26.0%), 287 (15.7%) registered with 1, 2, or 3+ GPs respectively by age 14 years. Changing practice was related to maternal age (aHRs; 95% CI: 0.96; 0.95,0.98), living in rural areas (0.75;0.56,0.99), initial registration with a non-SAIL-practice (2.16;1.60,2.93), recent address change (1.62;1.21,2.16), and no maternal educational qualifications (1.40;1.15,1.71). Overall, 305 (16.6%) children had never registered with a SAIL practice. Of 403 children initially registered with a SAIL practice who then changed practice, 66.7% re-registered with a SAIL practice. ConclusionsIn a nationally representative sample of Welsh children, the majority remained registered with the same practice up to age 14 years, with change in practice varying by maternal and household factors. Continuity of participation in the Welsh SAIL databank over early life is high, reflecting the high proportion of practices contributing, and the high proportion of children registered with them. Geographically contiguous primary care databanks, such as SAIL, enable a high proportion of children to be followed over time despite changing general practice.

Interventions that enhance health services for parents and infants to improve child development and social and emotional well-being in high-income countries: a systematic review

BACKGROUND

Experiences in the first 1000 days of life have a critical influence on child development and health. Health services that provide support for families need evidence about how best to improve their provision.

METHODS

We systematically reviewed the evidence for interventions in high-income countries to improve child development by enhancing health service contact with parents from the antenatal period to 24 months postpartum. We searched 15 databases and trial registers for studies published in any language between 01 January 1996 and 01 April 2016. We also searched 58 programme or organisation websites and the electronic table of contents of eight journals.

RESULTS

Primary outcomes were motor, cognitive and language development, and social-emotional well-being measured to 39 months of age (to allow the interventions time to produce demonstrable effects). Results were reported using narrative synthesis due to the variation in study populations, intervention design and outcome measurement. 22 of the 12 986 studies identified met eligibility criteria. Using Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group criteria, the quality of evidence overall was moderate to low. There was limited evidence for intervention effectiveness: positive effects were seen in 1/6 studies for motor development, 4/11 for language development, 4/8 for cognitive development and 3/19 for social-emotional well-being. However, most studies showing positive effects were at high/unclear risk of bias, within-study effects were inconsistent and negative effects were also seen. Intervention content and intensity varied greatly, but this was not associated with effectiveness.

CONCLUSIONS

There is insufficient evidence that interventions currently available to enhance health service contacts up to 24 months postpartum are effective for improving child development. There is an urgent need for robust evaluation of existing interventions and to develop and evaluate novel interventions to enhance the offer to all families.

PROSPERO REGISTRATION NUMBER

CRD42015015468.

Childhood asthma prevalence: cross-sectional record linkage study comparing parent-reported wheeze with general practitioner-recorded asthma diagnoses from primary care electronic health records in Wales

Introduction

Electronic health records (EHRs) are increasingly used to estimate the prevalence of childhood asthma. The relation of these estimates to those obtained from parent-reported wheezing suggestive of asthma is unclear. We hypothesised that parent-reported wheezing would be more prevalent than general practitioner (GP)-recorded asthma diagnoses in preschool-aged children.

Methods

1529 of 1840 (83%) Millennium Cohort Study children registered with GPs in the Welsh Secure Anonymised Information Linkage databank were linked. Prevalences of parent-reported wheezing and GP-recorded asthma diagnoses in the previous 12 months were estimated, respectively, from parent report at ages 3, 5, 7 and 11 years, and from Read codes for asthma diagnoses and prescriptions based on GP EHRs over the same time period. Prevalences were weighted to account for clustered survey design and non-response. Cohen’s kappa statistics were used to assess agreement.

Results

Parent-reported wheezing was more prevalent than GP-recorded asthma diagnoses at 3 and 5 years. Both diminished with age: by age 11, prevalences of parent-reported wheezing and GP-recorded asthma diagnosis were 12.9% (95% CI 10.6 to 15.4) and 10.9% (8.8 to 13.3), respectively (difference: 2% (−0.5 to 4.5)). Other GP-recorded respiratory diagnoses accounted for 45.7% (95% CI 37.7 to 53.9) and 44.8% (33.9 to 56.2) of the excess in parent-reported wheezing at ages 3 and 5 years, respectively.

Conclusion

Parent-reported wheezing is more prevalent than GP-recorded asthma diagnoses in the preschool years, and this difference diminishes in primary school-aged children. Further research is needed to evaluate the implications of these differences for the characterisation of longitudinal childhood asthma phenotypes from EHRs.

Measuring the timeliness of childhood vaccinations: Using cohort data and routine health records to evaluate quality of immunisation services

•

Most children received the first dose of primary vaccines on time.

•

Timeliness of vaccination decreased with vaccine dose.

•

Most children had appropriate intervals between doses; marked variation occurred.

•

The quality of routine vaccination records in Wales is high.

•

Parental report of MMR status is reliable.

Background

To achieve full benefits of vaccination programmes, high uptake and timely receipt of vaccinations are required.

Objectives

To examine uptake and timeliness of infant and pre-school booster vaccines using cohort study data linked to health records.

Methods

We included 1782 children, born between 2000 and 2001, participating in the Millennium Cohort Study and resident in Wales, whose parents gave consent for linkage to National Community Child Health Database records at the age seven year contact. We examined age at receipt, timeliness of vaccination (early, on-time, delayed, or never), and intervals between vaccine doses, based on the recommended schedule for children at that time, of the following vaccines: primary (diphtheria, tetanus, pertussis (DTP), polio, Meningococcal C (Men C), Haemophilus influenzae type b (Hib)); first dose of measles, mumps and rubella (MMR); and pre-school childhood vaccinations (DTP, polio, MMR). We compared parental report with child health recorded MMR vaccination status at age three years.

Results

While 94% of children received the first dose of primary vaccines early or on time, this was lower for subsequent doses (82%, 65% and 88% for second and third doses and pre-school booster respectively). Median intervals between doses exceeded the recommended schedule for all but the first dose with marked variation between children. There was high concordance (97%) between parental reported and child health recorded MMR status.

Conclusions

Routine immunisation records provide useful information on timely receipt of vaccines and can be used to assess the quality of childhood vaccination programmes. Parental report of MMR vaccine status is reliable.

Objectively measured physical activity and sedentary time: cross-sectional and prospective associations with adiposity in the Millennium Cohort Study

OBJECTIVE

To examine whether physical activity (PA) and sedentary time (ST) in primary school-aged children are associated with adiposity at the start of secondary school, and whether these associations differ by sex or ethnic group.

DESIGN

Nationally representative prospective cohort study.

SETTING

Children born across the UK, between 2000 and 2002.

PARTICIPANTS

6497 singleton children.

OUTCOME MEASURES

Measures of adiposity (body mass index (BMI), fat mass index (FMI) and fat free mass index (FFMI))--obtained at 7 and 11 years.

EXPLANATORY MEASURES

Total daily PA (mean counts per minute (cpm)); minutes of moderate-to-vigorous PA (MVPA); and ST. All assessed at 7 years using accelerometers.

RESULTS

In cross-sectional analyses, total PA was inversely associated with FMI (3.7% (95% CI 2.7% to 4.7%) reduction per 150 cpm increase), as was MVPA (4.2% (CI 3.2% to 5.2%) reduction per 20 min/day increase). Associations were stronger in black and South Asian ethnic groups. Total PA and MVPA were not associated with FFMI. ST was positively associated with FMI (1.3% (CI 0.2% to 2.3%) increase per 50 min/day increase) and inversely associated with FFMI (0.5% (CI 0.2% to 0.7%) reduction per 50 min/day increase). Longitudinally, MVPA at age 7 years remained inversely associated with FMI at age 11 years (1.5% (CI 0.4% to 2.6%) reduction per 20 min/day increase). No association was found between total PA and ST and any of the later adiposity measures.

CONCLUSIONS

7-year-old children who are more physically active are less likely to be obese at that age and at age 11 years. These associations were particularly evident in children from black or South Asian ethnicity at age 7 years and in boys at age 11 years. Measurements of fat mass provide valuable insights into ethnic differences in associations between adiposity and activity.

Social determinants of parent-child interaction in the UK

BACKGROUND

Children are shaped in part by their environment and one rich in communication is therefore beneficial. Activities such as play and reading have long lasting positive effects on development. This study examined the social and demographic characteristics of mothers who play with, read to and tell stories to their child, using data from the UK-wide Millennium Cohort Study (MCS).

METHODS

The study included 14 034 mothers of singleton 5-year-old children. Using data from the first and third sweeps of the MCS, we examined how often mothers engaged with their child in playing, reading and telling stories, according to their social and demographic characteristics: ethnicity, socio-economic status, highest academic qualification, lone mother status, age at birth of cohort child, number of children and employment status. Adjusted logistic regression analyses were conducted using Stata.

RESULTS

When their children were 5 years old, 22% of mothers reported playing, 51% reading and 13% telling stories everyday. Indian, Pakistani, Bangladeshi and Black mothers were significantly less likely to play with their child at least weekly compared with White mothers. The same applied to lone mothers compared with those living with a partner. Mothers with academic qualifications lower than degree level were less likely to read at least once weekly. Compared with mothers who worked full-time, those who worked part-time, were 'on-leave' or unemployed, were more likely to play with, and read to, their child at least weekly. Mothers with more than one child were significantly less likely to engage at least weekly in any of the three activities studied.

CONCLUSIONS

We found significant inequalities in the frequency of playing, reading and telling stories according to sociodemographic characteristics. This information is important to be able to target more effectively vulnerable children using established public health initiatives, like 'Bookstart' and 'Surestart', aimed at promoting play, reading and story telling.

How active are our children? Findings from the Millennium Cohort Study

OBJECTIVE

To describe levels of physical activity, sedentary time and adherence to Chief Medical Officers (CMO) physical activity guidelines among primary school-aged children across the UK using objective accelerometer-based measurements.

DESIGN

Nationally representative prospective cohort study.

SETTING

Children born across the UK, between 2000 and 2002.

PARTICIPANTS

6497 7-year-old to 8-year-old singleton children for whom reliable accelerometer data were available for at least 10 h a day for at least 2 days.

MAIN OUTCOME MEASURES

Physical activity in counts per minute (cpm); time spent in sedentary and moderate-to-vigorous intensity physical activity (MVPA); proportion of children meeting CMO guidelines (≥60 min/day MVPA); average daily steps.

EXPLANATORY MEASURES

Gender, ethnicity, maternal current/most recent occupation, lone parenthood status, number of children in the household and country/region of residence.

RESULTS

The median daily physical activity level was 595 cpm (IQR 507, 697). Children spent a median of 60 min (IQR 47-76) in MVPA/day and were sedentary for a median of 6.4 h/day (IQR 6-7). Only 51% met CMO guidelines, with girls (38%) less active than boys (63%). Children took an average of 10 229 (95% CI (8777 to 11 775)) steps each day. Children of Indian ethnicity were significantly less active overall than all other ethnic groups. Children of Bangladeshi origin and those living in Northern Ireland were least likely to meet CMO guidelines.

CONCLUSIONS

Only half of 7-year-old children in the UK achieve recommended levels of physical activity, with significant gender, ethnic and geographic variations. Longitudinal studies are needed to better understand the relevance of these (in)activity patterns for long-term health and well-being. In the meantime population-wide efforts to boost physical activity among young people are needed which are likely to require a broad range of policy interventions.

Predictors of non-response in a UK-wide cohort study of children's accelerometer-determined physical activity using postal methods

OBJECTIVES

To investigate the biological, social, behavioural and environmental factors associated with non-consent, and non-return of reliable accelerometer data (≥2 days lasting ≥10 h/day), in a UK-wide postal study of children's activity.

DESIGN

Nationally representative prospective cohort study.

SETTING

Children born across the UK, between 2000 and 2002.

PARTICIPANTS

13 681 7 to 8-year-old singleton children who were invited to wear an accelerometer on their right hip for 7 consecutive days. Consenting families were posted an Actigraph GT1M accelerometer and asked to return it by post.

PRIMARY OUTCOME MEASURES

Study consent and reliable accelerometer data acquisition.

RESULTS

Consent was obtained for 12 872 (94.5%) interviewed singletons, of whom 6497 (50.5%) returned reliable accelerometer data. Consent was less likely for children with a limiting illness or disability, children who did not have people smoking near them, children who had access to a garden, and those who lived in Northern Ireland. From those who consented, reliable accelerometer data were less likely to be acquired from children who: were boys; overweight/obese; of white, mixed or 'other' ethnicity; had an illness or disability limiting daily activity; whose mothers did not have a degree; who lived in rented accommodation; who exercised once a week or less; who had been breastfed; were from disadvantaged wards; had younger mothers or lone mothers; or were from households with just one, or more than three children.

CONCLUSIONS

Studies need to encourage consent and reliable data return in the wide range of groups we have identified to improve response and reduce non-response bias. Additional efforts targeted at such children should increase study consent and data acquisition while also reducing non-response bias. Adjustment must be made for missing data that account for missing data as a non-random event.

Seasonal variation in accelerometer-determined sedentary behaviour and physical activity in children: a review

AIM

To undertake a review of the methods and findings of published research evaluating the influence of season on accelerometer-determined sedentary behaviour (SB) and physical activity (PA) in children.

METHODS

A literature search was carried out using PubMed, Embase, Medline and Web of Science up to, and including, June 2011. The search strategy focused on four key elements: children, SB or PA, season and accelerometer. Articles were eligible for inclusion if they were published in English, included healthy study participants aged ≤ 18 years, reported at least one outcome variable derived from accelerometer-determined measurements, and compared SB or PA between two or more seasons, or controlled for season of measurement. Eligible papers were reviewed and evidence tables compiled reporting on publication year, country studied, study recruitment, consent rate, sample descriptives, study design, accelerometer protocol, valid accelerometer data receipt, season definition, statistical methods and key findings.

RESULTS

Sixteen of 819 articles were eligible for inclusion: children aged two to five years, six to twelve, or six to 18 years were included in five, six and five articles respectively. Six articles were from the UK, six from other European countries, three from the USA and one from New Zealand. Study sample sizes ranged from 64 to 5595. PA was reported in all articles but SB in only three. Only four studies were longitudinal and none of these reported SB. Seasonal variation in PA was reported in all UK studies, being highest in summer and lowest in winter. In four non-UK studies seasonal variation in PA was not found. Findings were inconclusive for SB.

CONCLUSION

There is sufficient evidence to support public health interventions aimed at increasing PA during winter in UK children. No conclusions can be drawn regarding the effect of season on children's SB reflecting few studies of small sample size, lack of repeat measures, incomparable definitions of season and inconsistent accelerometer protocols. Future research should determine factors that drive seasonal patterns in PA and SB in children such as age, sex, and geographic and climatic setting to inform interventions and target populations.

Is obesity associated with emotional and behavioural problems in children? Findings from the Millennium Cohort Study

Objectives. We examined cross-sectional and longitudinal associations between obesity and emotional and behavioural problems in a nationally representative sample of young children. Methods. Data were available from 11 202 children (50% boys) participating in the UK's Millennium Cohort Study. Height and weight were measured at 3 and 5 years and children defined as obese using IOTF cut-offs for body mass index (BMI). Emotional and behavioural problems were parentally assessed using the Strengths and Difficulties Questionnaire. Adjusted linear and multinomial regression analyses were conducted separately for boys and girls. Results. At age 3, obese boys had more conduct problems, and obese girls had more prosocial behaviours, than their normal weight counterparts. At age 5, obese boys had more conduct problems, hyperactivity and inattention problems, peer relationship problems and total difficulties. Obese girls only had more peer relationship problems. Obese 3-year-olds were not at increased risk of abnormal scores; in contrast, obese 5-year-old boys were significantly more likely to have abnormal scores for conduct problems, hyperactivity and inattention problems, peer relationship problems, prosocial behaviours and total difficulties. Obesity, at age 3, was also predictive of peer relationship problems at age 5 in boys (95% CI: 0.26 [0.01, 0.52]). Conclusions. Childhood obesity is associated with emotional and behavioural problems from a very young age. Obese boys are at particular risk. Further research is required to examine effect modifiers and mediating factors in these associations. Recognition and response to these mental health problems should be a goal of pediatric obesity interventions and policies.

Sex and ethnic differences in the waist circumference of 5-year-old children: findings from the Millennium Cohort Study

We examined sex and ethnic differences in central fatness, as assessed by waist circumference measurements, in 13 590 Millennium Cohort Study 5-year-olds. Measurements were expressed as z-scores based on reference data from the British Standards Institute. The cohort, especially girls, had larger waist circumference measurements than the reference population. Black children had larger waists, and children from other minority ethnic groups had smaller waists than White children. Girls, and Black children, in the United Kingdom are at particular risk for central fatness. Further research is needed to clarify ethnic and other influences on fat distribution, and the health outcomes associated with central fatness.

Self-esteem and quality of life in obese children and adolescents: a systematic review

Although an increasing number of children and adolescents are becoming obese, the psychological morbidities associated with obesity are not well established. Existing reviews report modest associations between obesity and global self-esteem. However, none have examined how this affects multi-component assessments of self-esteem and quality of life in young people with defined obesity. A literature search identified 17 self-esteem and 25 quality of life studies of cross-sectional, longitudinal or intervention design published since 1994. Child-completed and parent-proxy assessments were consistent in showing significant reductions in global self-esteem and quality of life in obese youth. Competences particularly affected were physical competence, appearance and social functioning. There were no clear differences in effects between children and adolescents, and evidence on gender and ethnicity was lacking. Competency improvements occurred in the presence and absence of weight loss, suggesting their value as intervention outcomes and the need for further investigation.

Associations between sport and screen-entertainment with mental health problems in 5-year-old children

BACKGROUND

Few studies have examined the benefits of regular physical activity, and risks of sedentary behaviour, in young children. This study investigated associations between participation in sports and screen-entertainment (as components of physical activity and sedentary behaviour), and emotional and behavioural problems in this population.

METHODS

Cross-sectional analysis of data from 13470 children (50.9% boys) participating in the nationally representative UK Millennium Cohort Study. Time spent participating in sports clubs outside of school, and using screen-entertainment, was reported by the child's mother at child age 5 years, when mental health was also measured using the Strengths and Difficulties Questionnaire.

RESULTS

45% of children did not participate in sport clubs and 61% used screen-entertainment for >/= 2 hours per day. Children who participated in sport had fewer total difficulties; emotional, conduct, hyperactivity-inattention and peer relationship problems; and more prosocial behaviours. These relationships were similar in boys and girls. Boys and girls who used screen-entertainment for any duration, and participated in sport, had fewer emotional and behavioural problems, and more prosocial behaviours, than children who used screen-entertainment for >/= 2 hours per day and did not participate in sport.

CONCLUSIONS

Longer durations of screen-entertainment usage are not associated with mental health problems in young children. However, our findings suggest an association between sport and better mental health. Further research based on longitudinal data is required to examine causal pathways in these associations and to determine the potential role of this and other forms of physical activity in preventing mental health disorders.

Perceived and objective measures of the neighbourhood environment and overweight in preschool children and their mothers

OBJECTIVES

The primary aim was to examine the relationships between perceived and objective measures of the neighbourhood environment, measured in late infancy, and subsequent overweight (including obesity) in 3-year-old children and their mothers. The secondary aim was to assess whether moving residence confounded these relationships.

METHODS

We analysed data on 8 154 children and their mothers from the UK Millennium Cohort Study who had participated since birth and were living in England. At the first contact (late infancy), mothers reported their perceptions of their neighbourhood environment, and objective measures of the neighbourhood environment were obtained by linking national deprivation data to each child's postcode. We conducted logistic and multilevel regression analyses to examine perceived and objective measures of the neighbourhood environment, respectively, and overweight at the second contact (3 years) in children and their mothers. All analyses were adjusted for moving residence.

RESULTS

There were few consistent patterns between measures of the neighbourhood environment (perceived or objective) and early childhood overweight. However, mothers' risk of overweight increased with increasingly poor neighbourhood conditions (perceived) or residence in areas of increasing deprivation (objective), after adjustment for individual socio-demographic factors. All relationships were maintained after adjustment for moving residence.

CONCLUSIONS

While area-level factors have limited influence on the development of overweight in preschool children, they are likely to affect overweight in their mothers. Policies need to address both individual and environmental factors to tackle obesity and its determinants across the life course.

Effects of infant feeding practice on weight gain from birth to 3 years

OBJECTIVE

The influence of infant feeding practices on weight gain during childhood remains unresolved, with few studies adjusting appropriately for confounding factors. This study examined the effect of breastfeeding initiation, breastfeeding duration and age at introduction of solid foods on weight gain from birth to 3 years.

DESIGN

Nationally representative prospective study.

SETTING

England, Wales, Scotland and Northern Ireland.

PARTICIPANTS

10,533 3-year-old children from the UK Millennium Cohort Study.

MAIN OUTCOME MEASURE

Conditional weight gain z-scores from birth to 3 years (adjusted for birthweight); multiple linear regression analyses were conducted to examine the impact of infant feeding practices on this measure after adjustment for confounding factors.

RESULTS

Breastfeeding initiation and breastfeeding duration were significantly associated with weight gain from birth to 3 years. Infants receiving no breast milk grew faster than those whose mothers initiated breastfeeding (adjusted regression coefficient (difference in z-scores) 0.06, 95% CI 0.02 to 0.09), as did those breastfed for less than 4 months (0.05, 95% CI 0.01 to 0.09) versus those breastfed 4 months or longer. Early introduction of solids was not associated with faster weight gain after adjustment for height z-score at 3 years (-0.01, 95% CI -0.04 to 0.03).

CONCLUSIONS

Initiating and prolonging breastfeeding may reduce excess weight gain by preschool age. Association of the early introduction of solids with rapid weight gain during early childhood is mediated through childhood stature. Although effects sizes are small, at a population level they are of public health importance as these risk factors are potentially modifiable. Strategies to support mothers to follow internationally recommended infant feeding practices are required.

The impact of weight-related victimization on peer relationships: the female adolescent perspective

OBJECTIVE

Obesity is associated with undesirable psychological and social consequences. This qualitative study examined the relationship between obesity and victimization, and the impact this has on peer relationships.

METHODS AND PROCEDURES

Five obese female adolescents participated in multiple, semi-structured, in-depth interviews. Interview transcriptions were analyzed using Interpretative Phenomenological Analysis (IPA).

RESULTS

Weight-related victimization experiences were common and their impact on peer relationships was complex. Low self-confidence, isolation, and peer anxiety were all identified as resulting from victimization and were all barriers to developing peer relationships. Participants sought protection from victimization by seeking the "ideal" nonjudgmental empathetic best friend(s) and supportive family members to shield them from negative experiences. However there was also evidence that, while they were guarded with their own feelings, the experience of victimization increased empathy in these obese female adolescents.

DISCUSSION

Social and psychological consequences of obesity in female adolescents are widespread, suggesting the importance of listening to those affected. Peer relationships have the opportunity to both amplify and reduce the psychological impact of living with obesity and victimization. Greater understanding of the social networks of obese adolescents and their impact on well-being is needed, as well as methods to reduce negative experiences through childhood obesity treatment and school-based prevention programs.

Regional differences in overweight: an effect of people or place?

OBJECTIVE

To examine UK country and English regional differences in childhood overweight (including obesity) at 3 years and determine whether any differences persist after adjustment for individual risk factors.

DESIGN

Nationally representative prospective study.

SETTING

England, Wales, Scotland and Northern Ireland.

PARTICIPANTS

13 194 singleton children from the UK Millennium Cohort Study with height and weight data at age 3 years.

MAIN OUTCOME MEASURE

Overweight (including obesity) was defined according to the International Obesity TaskForce cut-offs for body mass index, which are age and sex specific.

RESULTS

At 3 years of age, 23% (3102) of children were overweight or obese. In univariable analyses, children from Northern Ireland (odds ratio 1.30, 95% confidence interval 1.14 to 1.48) and Wales (1.26, 1.11 to 1.44) were more likely to be overweight than children from England. There were no differences in overweight between children from Scotland and England. Within England, children from the East (0.71, 0.57 to 0.88) and South East regions (0.82, 0.68 to 0.99) were less likely to be overweight than children from London. There were no differences in overweight between children from other English regions and children from London. These differences were maintained after adjustment for individual socio-demographic characteristics and other risk factors for overweight.

CONCLUSIONS

UK country and English regional differences in early childhood overweight are independent of individual risk factors. This suggests a role for policies to support environmental changes that remove barriers to physical activity or healthy eating in young children.

Do early infant feeding practices vary by maternal ethnic group?

Objective

To examine UK country and ethnic variations in infant feeding practices.

Design

Cohort study.

Setting

Infants enrolled in the Millennium Cohort Study, born between September 2000 and January 2002.

Subjects

A total of 18 150 natural mothers (11 286 (8207 white) living in England) of singleton infants.

Outcome measures

Breast-feeding initiation, breast-feeding discontinuation and introduction of solid foods before 4 months.

Explanatory variables

Maternal ethnic group, education and social class.

Results

Seventy per cent of UK mothers started to breast-feed, of whom 62% stopped before 4 months. Median age at discontinuing breast-feeding was 14, 13, 10 and 6 weeks in Scotland, England, Wales and Northern Ireland, respectively. Thirty-six per cent of UK mothers (34% in England) introduced solids before 4 months. White mothers were more likely to discontinue breast-feeding (62%) and introduce solids early (37%) than most other ethnic minority groups; those stopping before 4 months were more likely to introduce solids early compared with those continuing to breast-feed beyond this age (adjusted rate ratio (95% confidence interval): 1.3 (1.1–1.2)). Educated mothers were less likely to stop breast-feeding before 4 months (white mothers, 0.8 (0.8–0.9); non-white mothers, 0.9 (0.8–1.0)) than those with no/minimal qualifications but, among ethnic minorities, were more likely to introduce solids early (1.3 (1.0–1.6)). Socio-economic status was positively associated with breast-feeding continuation among white women, and with age at introduction of solids among non-white women.

Conclusions

We have identified important geographic, ethnic and social inequalities in breast-feeding continuation and introduction of solids within the UK, many of which have not been reported previously. The factors mediating these associations are complex and merit further study to ensure that interventions proposed to promote maternal adherence to current infant feeding recommendations are appropriate and effective.

Maternal employment and breast-feeding initiation: findings from the Millennium Cohort Study

Maternal employment rates have increased rapidly in recent years and little is known about how this influences whether women start breast feeding. We examined data from the Millennium Cohort Study to determine whether a mother's employment status (full-time, part-time, self-employed, on leave, not employed/student) and employment characteristics are related to breast-feeding initiation. This analysis comprised 14 830 white mothers from Britain and Ireland (6917 employed) with singleton babies, born from 2000 to 2002. Information was obtained on infant feeding history and mother's employment when the cohort child was 9 months old. We found that women employed full-time were less likely to initiate breast feeding than mothers who were not employed/students, after adjustment for confounding factors [adjusted rate ratio (aRR) = 0.92; 95% confidence interval (CI) 0.89, 0.96]; however, there were no differences in breast-feeding initiation between mothers employed part-time, self-employed, or on leave and mothers who were not employed/students. Among employed mothers, those who returned to work within 4 months postpartum were less likely to start breast feeding than women who returned at 5 or 6 months [aRR = 0.95; 95% CI 0.92, 0.99], and women who returned within the first 6 weeks were much less likely to start breast feeding [aRR = 0.85; 95% CI 0.77, 0.94]. Mothers returning for financial reasons were also less likely to initiate breast feeding [aRR = 0.96; 95% CI 0.93, 0.99] than those who returned for other reasons. Policies to increase breast feeding should address how both the time and circumstances of a mother's return to employment postpartum influence whether she decides to start breast feeding.

Differential parental weight and height contributions to offspring birthweight and weight gain in infancy

BACKGROUND

Parental weight and height correlate with offspring birthweight and weight gain, suggesting genetic and environmental influences on fetal growth. The differential contributions of the mother's and father's height and weight to birthweight, or weight gain in infancy, remain unclear and were examined using data from the UK Millennium Cohort Study.

METHODS

We calculated z-scores for birthweight and conditional weight gain to age 9 months (weight gain adjusted for birthweight) for 6811 term white singleton infants living with natural parents, using the British 1990 growth reference. We also calculated parental height and weight z-scores. The effects of parental size on birthweight and weight gain were analysed using multivariable regression, with a novel reparameterization to test for differences in effect size between mother and father.

RESULTS

Maternal weight had a far greater influence than paternal weight on birthweight [coefficient for the difference between parents (95% CI): 0.15 (0.100.20)], while parental height contributions were similar [0.03 (-0.02 to 0.07)]. Weights and heights of mothers and fathers contributed equally to infant weight gain [difference coefficients -0.03 (-0.09 to 0.02) and 0.02 (-0.03 to 0.07), respectively].

CONCLUSIONS

The influences of parental height and weight on birthweight and infant weight gain are similar for the two parents, with the exception of the influence of weight on birthweight where the mother is much more influential than the father. Parental size associations with infant growth result from a complex combination of genetic and environmental influences. This novel reparameterization of parental anthropometry is applicable to other studies examining parental influences on offspring size and growth across the life course.

Are breastfeeding rates higher among mothers delivering in Baby Friendly accredited maternity units in the UK?

BACKGROUND

The promotion and support of breastfeeding is a global priority with benefits for maternal and infant health, particularly in low-income and middle-income countries where its relevance for child survival is undisputed. However, breastfeeding rates are strikingly low in some higher-income countries, including the UK. Evidence to support the effectiveness of public health interventions to increase rates of breastfeeding initiation and duration in this setting is limited. We examined whether mothers were more likely to start and continue to breastfeed if they delivered in a UNICEF UK Baby Friendly accredited maternity unit, in a cohort with a high representation of disadvantaged and lower socioeconomic groups with traditionally low rates of breastfeeding.

METHODS

We analysed maternally reported breastfeeding initiation and prevalence of any breastfeeding at 1 month for 17 359 singleton infants according to maternity unit Baby Friendly Initiative participation status at birth (accredited, certificated, or neither award).

RESULTS

Mothers delivering in accredited maternity units were more likely to start breastfeeding than those delivering in units with neither award [adjusted rate ratio: 1.10, 95% confidence interval (CI) 1.05-1.15], but were not more likely to breastfeed at 1 month (0.96, 95% CI 0.84-1.09), after adjustment for social, demographic, and obstetric factors. Antenatal class attendance (1.14, 95% CI 1.11-1.17), vaginal delivery (1.05, 1.03-1.08), a companion at delivery (1.09, 1.04-1.16), and maternal post-partum hospital stay >24 h (1.06, 1.04-1.09) were also independently associated with breastfeeding initiation.

CONCLUSIONS

Policies to increase the proportion of maternity units participating in the UNICEF UK Baby Friendly Initiative are likely to increase breastfeeding initiation but not duration. Other strategies are required in order to support UK mothers to breastfeed for the recommended duration.

Obesity and bullying: different effects for boys and girls

AIMS

To investigate whether weight category (underweight, average weight, overweight, and obese) at age 7.5 predicts bullying involvement at 8.5 years. Models were tested separately for boys and girls to investigate gender differences in association patterns.

METHODS

Prospective cohort study in southwest England. Height and weight were measured in children at age 7.5 (n = 8210). BMI (kg/m2) was used to define underweight, average weight, overweight, and obese children, according to British age and gender specific growth reference data. Overt (n = 7083) and relational (n = 6932) bullying behaviour was assessed in children at age 8.5.

RESULTS

After adjustment for parental social class, compared to average weight boys, obese boys were 1.66 (95% CI 1.04 to 2.66) times more likely to be overt bullies and 1.54 (1.12 to 2.13) times more likely to be overt victims. Obese girls were 1.53 (1.09 to 2.15) times more likely to be overt victims compared to average weight girls.

CONCLUSIONS

Obesity is predictive of bullying involvement for both boys and girls. Preadolescent obese boys and girls are more likely to be victims of bullying because they deviate from appearance ideals. Other obese boys are likely to be bullies, presumably because of their physical dominance in the peer group.