The effects of environmental tobacco smoke on health services utilization in the first eighteen months of life

Assessing the safety of lipid-modifying medications among Chinese adolescents: a drug-target Mendelian randomization study

BACKGROUND

With increasing hypercholesterolemia prevalence in East Asian adolescents, pharmacologic interventions (e.g., HMGCR inhibitors (statins) and PCSK9 inhibitors) may have to be considered although their longer-term safety in the general adolescent population is unclear. This study aims to investigate the longer-term safety of HMGCR inhibitors and PCSK9 inhibitors among East Asian adolescents using genetics.

METHODS

A drug-target Mendelian randomization study leveraging the Global Lipid Genetics Consortium (East Asian, n = 146,492) and individual-level data from Chinese participants in the Biobank clinical follow-up of Hong Kong's "Children of 1997" birth cohort (n = 3443, aged ~ 17.6 years). Safety outcomes (n = 100) included anthropometric and hematological traits, renal, liver, lung function, and other nuclear magnetic resonance metabolomics. Positive control outcomes were cholesterol markers from the "Children of 1997" birth cohort and coronary artery disease from Biobank Japan.

RESULTS

Genetic inhibition of HMGCR and PCSK9 were associated with reduction in cholesterol-related NMR metabolomics, e.g., apolipoprotein B (HMGCR: beta [95% CI], - 1.06 [- 1.52 to - 0.60]; PCSK9: - 0.93 [- 1.56 to - 0.31]) and had the expected effect on the positive control outcomes. After correcting for multiple comparisons (p-value < 0.006), genetic inhibition of HMGCR was associated with lower linoleic acid - 0.79 [- 1.25 to - 0.35]. Genetic inhibition of PCSK9 was not associated with the safety outcomes assessed.

CONCLUSIONS

Statins and PCSK9 inhibitors in East Asian adolescents appeared to be safe based on the outcomes concerned. Larger studies were warranted to verify these findings. This study serves as a proof of principle study to inform the medication safety among adolescents via genetics.

Maternal Smoking in Pregnancy and Child's Hospital Use up to 5 Years of Age in a Data Linkage Birth Cohort

OBJECTIVES

To examine if exposure to maternal smoking during pregnancy is associated with emergency department (ED) presentation and admission through the ED in children up to 5 years after birth.

METHODS

Antenatal records of all children up to 5 years of age who were born in Tasmania, Australia, between July 2008 and June 2014 were linked to health service use (ED presentations and hospital admissions). Negative binomial regression was used to estimate the incidence rate ratio (IRR) and 95% confidence intervals (CIs) at ≤1 year and ≤5 years for ED presentations and admissions to the hospital through the ED for any reason and by 9 major disease categories for children exposed versus children not exposed to maternal smoking during pregnancy. Models were adjusted for sex, socioeconomic position, maternal age at birth, and region of residence. Presentations and admissions for poisoning and injuries were used as a negative control.

RESULTS

Among 36 630 infants, 21% were exposed to maternal smoking during pregnancy. Exposed children had a 26% higher rate of presentation to the ED (IRR_adjusted 1.26; 95% CI 1.23-1.29) and a 45% higher rate of admission (IRR_adjusted 1.45; 95% CI 1.39-1.51) at up to 5 years of age. Compared with the negative control, higher presentation and admission rates were evident in respiratory; eyes, ears, nose, and throat; psychosocial; and infectious disease categories.

CONCLUSIONS

Higher health care service use was observed in children exposed to maternal smoking during pregnancy for a range of conditions associated with exposure to smoking. The findings reinforce the need to reduce smoking among people in their childbearing years.

Systematic Review of Behaviour Change Techniques within Interventions to Reduce Environmental Tobacco Smoke Exposure for Children

Children are particularly vulnerable to environmental tobacco smoke (ETS). There is no routine support to reduce ETS in the home. We systematically reviewed trials to reduce ETS in children in order to identify intervention characteristics and behaviour change techniques (BCTs) to inform future interventions. We searched Medline, EMBASE, CINAHL, PsycINFO, ERIC, Cochrane Central Register of Controlled Trials, and Cochrane Tobacco Addiction Group Specialised Register from January 2017 to June 2020 to update an existing systematic review. We included controlled trials to reduce parent/caregiver smoking or ETS in children <12 years that demonstrated a statistically significant benefit, in comparison to less intensive interventions or usual care. We extracted trial characteristics; and BCTs using Behaviour Change Technique Taxonomy v1. We defined "promising" BCTs as those present in at least 25% of effective interventions. Data synthesis was narrative. We included 16 trials, of which eight were at low risk of bias. All trials used counselling in combination with self-help or other supporting materials. We identified 13 "promising" BCTs centred on education, setting goals and planning, or support to reach goals. Interventions to reduce ETS in children should incorporate effective BCTs and consider counselling and self-help as mechanisms of delivery.

The effect of sleep duration on hemoglobin and hematocrit: observational and Mendelian randomization study

STUDY OBJECTIVE

Observationally sleep duration is positively associated with hemoglobin (Hgb), whether this association is causal and consistent by sex remains unclear. Here, we assessed the association of sleep duration with Hgb and hematocrit (Hct) observationally in late adolescence in a population-representative Chinese birth cohort "Children of 1997" with validation using Mendelian randomization (MR) in adults.

METHODS

In the "Children of 1997" birth cohort (recruited = 8327, included = 3144), we used multivariable linear regression to assess the adjusted associations of sleep duration (measured as time in bed) with Hgb and Hct at 17.5 years and any sex differences. Using two-sample MR, we assessed the effect of sleep duration on Hgb and Hct, based on 61 single nucleotide polymorphisms (SNPs) applied to genome-wide association studies of Hgb and Hct in adults (n = 361 194).

RESULTS

Observationally, self-reported sleep duration was positively associated with Hct (0.034 standard deviations [SDs] per hour, 95% confidence interval [CI] 0.019 to 0.049), but not with Hgb. Using MR longer sleep increased Hct (0.077 SD per hour, 95% CI 0.035 to 0.119) and Hgb (0.065 SD per hour, 95% CI 0.020 to 0.109) using Mendelian randomization pleiotropy residual sum and outlier (MR PRESSO), with more pronounced associations in men.

CONCLUSIONS

Our novel findings indicate sleep increases both Hgb and Hct, particularly in men, perhaps contributing to its restorative qualities. Potential difference by sex and the implications of these findings warrant investigation.

Associations of household environmental tobacco smoke exposure with respiratory symptoms and utilisation of medical services in healthy young children in Hong Kong

INTRODUCTION

Young children are especially vulnerable to environmental tobacco smoke (ETS) exposure. This study was carried out to determine whether household ETS exposure was associated with respiratory symptoms and medical service utilisation among Hong Kong healthy children in their first eighteen months of age.

METHODS

A secondary analysis was done on the data obtained from our previous cross-sectional territory-wide pneumococcal carriage surveillance study in Hong Kong in 2013–2014. All measures were reported by caregivers. Univariable and multivariable analyses were performed to examine the associations between ETS exposure and outcome measures. Covariates included children’s sex, age, body mass index z score, history of breastfeeding, gestational age at birth, birthweight, maternal age, living region, overcrowding of living area, household income, child care attendance, and presence of siblings. Additional adjustment for season and households’ respiratory symptoms were made to ascertain the association between ETS and children’s respiratory symptoms.

RESULTS

The analysis included 1541 children (mean age: 11.2 ± 6.4 months; males: 50.7%). Current household ETS exposure (AOR=1.30; 95% CI: 1.00– 1.66; p=0.050) and postnatal maternal smoking (AOR=2.21; 95% CI: 1.06–4.64; p=0.035) were independently and significantly associated with all-cause doctor consultation in the past 3 months. Children living with more than one household smoker were more likely to have all-cause doctor consultation compared with the non-exposed children (AOR=1.70; 95% CI: 1.04–2.77, p=0.028). Postnatal maternal smoking was associated with all-cause hospitalisation in the past 3 months (AOR=2.48; 95% CI: 1.05–5.86; p=0.039). Children living in a household, where the daily consumption by household smokers was more than 20 cigarettes, were more likely to have respiratory symptoms compared with non-exposed children (AOR=1.99; 95% CI: 1.12–3.52; p=0.016).

CONCLUSIONS

Household ETS exposure in young children was associated with respiratory symptoms and all-cause outpatient or inpatient medical service utilisation. The associations were potentially dose-dependent.

Birth weight and prematurity with lung function at ~17.5 years: "Children of 1997" birth cohort

We aimed to determine if prematurity and lower birth weight are associated with poorer lung function in a non-western developed setting with less marked confounding by socioeconomic position. Using multivariable linear regression in Hong Kong’s “Children of 1997” birth cohort, adjusted associations of prematurity and birth weight with forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and forced expiratory flow at 25–75% of the pulmonary volume (FEF_25–75%) at ~17.5 years were assessed. Associations for birth weight were stronger in boys for FEV₁ (boys: 0.31 L, 95% confidence interval (CI) 0.24 to 0.38, girls: 0.18 L, 95% CI 0.12 to 0.25), FVC (boys: 0.36 L, 95% CI 0.27 to 0.44, girls: 0.22 L, 95% CI 0.15 to 0.28) and FEF_25–75% (boys: 0.35 L, 95% CI 0.21 to 0.49, girls: 0.22 L, 95% CI 0.09 to 0.34) adjusted for age, socioeconomic position and infant and maternal characteristics. Similarly adjusted, preterm birth (compared to full-term birth) was associated with lower FEV₁/FVC and FEF_25–75%. Thus, associations of lower birth weight, especially in boys, and prematurity with poorer lung function at 17.5 years were found. Identifying underlying mechanism might contribute to the improvement of pulmonary health and the prevention of adult respiratory illness.

Exposure to secondhand smoke in vehicles among Canadian adolescents: Years after the adoption of smoke-free car laws

Exposure to secondhand smoke (SHS) can result in several adverse health consequences. SHS concentrations in vehicles can significantly exceed levels present in other enclosed spaces. Years after the adoption of smoke-free car laws, this study examined the prevalence of exposure to SHS in vehicles among adolescents. Data were utilized from the 2016-2017 Canadian Student Tobacco, Alcohol and Drugs Survey (n = 48,444). The prevalence of exposure to SHS in cars was estimated by grade level and demographic characteristics. The results showed a gradient by grade level in exposure to SHS with students in upper-grade levels reporting a higher prevalence of SHS in cars. SHS varied by province, with the lowest rate found in British Columbia (15.6%) and the highest in Saskatchewan (36.9%). The provinces with laws that extend protections to older children also had high rates of SHS exposure among students in upper-grade levels. Students exposed to SHS were more likely to engage in risky behaviors, including the use of marijuana, alcohol, cigarettes, and e-cigarettes. Despite laws prohibiting smoking in vehicles carrying children, SHS prevalence remains high. While enforcement of these laws may be challenging, persuasion campaigns highlighting that children are especially vulnerable to the health risks of SHS may be beneficial.

Economic Costs Attributable to Smoking in Hong Kong in 2011: A Possible Increase From 1998

BACKGROUND

Reduction in smoking prevalence does not necessarily reduce the costs of smoking as evidence shows in developed countries. We provide up-to-date estimates for direct and indirect costs attributable to smoking in Hong Kong in 2011 and compare with our 1998 estimates.

METHODS

We took a societal perspective to include lives and life years lost, health care costs and time lost from work in the costing. We followed guidelines on estimating costs of active smoking for those aged 35 years or above (35+) and costs due to second-hand smoking (SHS) exposure for 35+, infants aged 12 months and under and children aged 15 and below. All costs are in US dollars.

RESULTS

We estimated that 6154 deaths among 35+ in Hong Kong in 2011 were attributable to active smoking, an increase of 10% from 1998. Besides, 672 deaths were attributable to SHS exposure, that is, 10% of the total 6826 smoking-attributable deaths. The estimate of productive life lost due to deaths from active smoking by those aged under 65 years in 2011 was $166 million, an increase of about 4% over the estimate in 1998. Our conservative estimate of the annual tobacco-related disease cost in 2011 was $716 million which accounted for 0.3% of GDP. If we added the value of attributable lives lost, the annual cost would be $4.7 billion.

CONCLUSION

Despite the reduction in smoking prevalence, smoking-attributable disease still imposes a substantial economic burden on Hong Kong society. These findings support more stringent and effective tobacco control legislation, policies, and measures.

IMPLICATIONS

Current evidence shows reduction in smoking prevalence does not necessarily reduce the economic costs of smoking. Most studies in developed countries employed a societal perspective, including costs of productivity loss and indirect costs, but not all studies estimated costs associated with second-hand smoking (SHS). The present study estimated the total costs of smoking in Hong Kong including direct and indirect costs attributable to active smoking and to SHS exposure. Our study confirms the pattern of smoking epidemic in developed countries, forewarns the increasing economic burdens from tobacco, and provides East Asian countries with a prediction of their own future costs.

Association of infant growth with emergence of permanent dentition among 12 year-aged southern Chinese school children

BACKGROUND

There is a need to comprehensively investigate the relationship between tooth eruption and infant growth to explain the theory of tooth emergence. This study aimed to investigate the association between infant growth during the first year of life and the emergence of the permanent teeth.

METHODS

A random sample of 668, 12-year-old students was recruited from a birth cohort. Erupted permanent tooth number was recorded. The association of infant growth (growth trajectories and growth rates) and permanent tooth emergence was examined through logistic regression analyses. The regression model was adjusted by potential confounders including gender, gestational age, mode of delivery, type of feeding, parental education, and health status.

RESULTS

The response rate was 76.9% (n = 514). Two hundred and forty-five (47.7%) children had all 28 permanent teeth erupted. Infants who had higher birth weight z-scores and those who had grown slowly during the first three months of life were more likely to have complete permanent teeth emergence at their 12-year-old in both unadjusted (p <  0.01) and adjusted model (adjusted for gender, gestational age, mode of delivery, type of feeding, parental education, and health status, p <  0.01). However, no significant association was found between the growth trajectories and permanent tooth emergence in either unadjusted or adjusted models (p > 0.05).

CONCLUSION

Birth weight and infant growth during the first three months of life might be associated with permanent tooth emergence at their 12 years of age. This association may be applied in the assessment of risk for dental caries or malocclusion.

Sleep duration and risk of diabetes: Observational and Mendelian randomization studies

Inadequate sleep could contribute to type 2 diabetes, but observational studies are inconsistent and open to biases, particularly from confounding. We used Mendelian randomization (MR) to obtain an unconfounded estimate of the effect of sleep duration on diabetes, fasting glucose (FG) and hemoglobin A1c (HbA1c), and an observation study to assess differences by sex. Using MR, we assessed the effects of genetically instrumented sleep on diabetes, based on 68 single nucleotide polymorphisms (SNPs), applied to the DIAbetes Genetics Replication and meta-analysis case (n = 26,676)-control (n = 132,532) study and on FG and HbA1c, based on 55 SNPs, applied to the Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC) study of FG (n = 122,743) and HbA1c (n = 123,665). In the population-representative Hong Kong Chinese "Children of 1997" birth cohort we assessed whether associations of sleep duration at ~17.5 years with FG and HbA1c differed by sex. Using inverse variance weighting with multiplicative random effects, sleep duration was not associated with diabetes (odds ratio (OR) 0.85 per hour of sleep, 95% confidence interval (CI) 0.64 to 1.13), FG (-0.032 mmol/l per hour of sleep, 95% CI -0.126 to 0.063) or HbA1c (-0.022% per hour of sleep, 95% CI -0.069 to 0.024). In "Children of 1997", the associations of sleep duration with FG differed by sex (p for interaction 0.05) but not with HbA1c. Overall sleep duration does not appear to be related to diabetes, FG or HbA1c, but the possibility of sex differences merits investigation.

In utero exposure to gestational diabetes and adiposity: does breastfeeding make a difference?

BACKGROUND/OBJECTIVES

Short-term breastfeeding from mothers with gestational diabetes (GDM) may programme metabolism and increase offspring diabetes risk. We examined the association of in utero GDM exposure with adiposity from infancy to adolescence, and whether any association was modified by breastfeeding during early infancy.

METHODS

In the prospective Chinese birth cohort "Children of 1997" (n = 7342, 88% follow-up rate), generalised estimate equations with multiple imputation were used to assess associations of in utero GDM exposure with age- and sex-specific body mass index (BMI) z-score during infancy (3 and 9 months), childhood (2- < 8 years) and adolescence (8-16 years), adjusted for sex, parity, maternal age, birth place, preeclampisa, smoking, and family socio-economic position. We also tested whether the associations differed by mode of infant feeding (always formula-fed, mixed, always breastfed) during the first three months of life.

RESULTS

In utero GDM exposure (7.5%) was associated with a lower BMI z-score during infancy (-0.13, 95% confidence interval (CI) -0.22, -0.05) but higher BMI z-scores during childhood (0.14, 95% CI 0.03, 0.25) and adolescence (0.25 95% CI 0.11, 0.38). Breastfeeding for the first three months did not modify the association of in utero GDM status with subsequent BMI (all p values for interaction >0.4).

CONCLUSIONS

In utero GDM exposure was associated with greater adiposity during childhood and adolescence. Breastfeeding in early infancy from mothers with GDM was not associated with greater adiposity in children and thus should still be encouraged.

Paternal smoking and maternal protective behaviors at home on infant's saliva cotinine levels

BackgroundWe investigated the association between paternal smoking, avoidance behaviors and maternal protective actions and smoke-free home rules with infant's saliva cotinine in Hong Kong.MethodsSix hundred and seventy-five non-smoking mothers (mean age 32.6 years) who attended the maternal-child health clinics with their newborns aged ≤18 months completed a questionnaire about paternal smoking and avoidance behaviors, maternal protective actions, smoke-free rules at home, and infant's second-hand smoke (SHS) exposure. Three hundred and eighty-nine infants provided saliva sample and its cotinine was tested.ResultsThe geometric mean of infant's saliva cotinine was 1.07 ng/ml (95% confidence interval (CI): 0.98, 1.16). Infants living in smoking families with SHS exposure had significantly higher cotinine level than in non-smoking families (adjusted β=0.25, 95% CI: 0.16, 0.33). Paternal smoking near infants (within 1.5 m) was associated with higher cotinine level (adjusted β=0.60, 95% CI: 0.22, 0.98), which was not reduced by avoidance behaviors (e.g., smoking in kitchen or balcony). Even fathers smoking ≥3 m away from infants was associated with higher cotinine level than non-smoking families (adjusted β=0. 09, 95% CI: 0.01, 0.16). Maternal protective actions and smoke-free home rules were not significantly associated with reduced cotinine level.ConclusionPaternal smoking avoidance, maternal protective actions, and smoke-free policy at home did not reduce infant's saliva cotinine.

Family and carer smoking control programmes for reducing children's exposure to environmental tobacco smoke

BACKGROUND

Children's exposure to other people's tobacco smoke (environmental tobacco smoke, or ETS) is associated with a range of adverse health outcomes for children. Parental smoking is a common source of children's exposure to ETS. Older children in child care or educational settings are also at risk of exposure to ETS. Preventing exposure to ETS during infancy and childhood has significant potential to improve children's health worldwide.

OBJECTIVES

To determine the effectiveness of interventions designed to reduce exposure of children to environmental tobacco smoke, or ETS.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialised Register and conducted additional searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PsycINFO, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Education Resource Information Center (ERIC), and the Social Science Citation Index & Science Citation Index (Web of Knowledge). We conducted the most recent search in February 2017.

SELECTION CRITERIA

We included controlled trials, with or without random allocation, that enrolled participants (parents and other family members, child care workers, and teachers) involved in the care and education of infants and young children (from birth to 12 years of age). All mechanisms for reducing children's ETS exposure were eligible, including smoking prevention, cessation, and control programmes. These include health promotion, social-behavioural therapies, technology, education, and clinical interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies and extracted data. Due to heterogeneity of methods and outcome measures, we did not pool results but instead synthesised study findings narratively.

MAIN RESULTS

Seventy-eight studies met the inclusion criteria, and we assessed all evidence to be of low or very low quality based on GRADE assessment. We judged nine studies to be at low risk of bias, 35 to have unclear overall risk of bias, and 34 to have high risk of bias. Twenty-one interventions targeted populations or community settings, 27 studies were conducted in the well-child healthcare setting and 26 in the ill-child healthcare setting. Two further studies conducted in paediatric clinics did not make clear whether visits were made to well- or ill-children, and another included visits to both well- and ill-children. Forty-five studies were reported from North America, 22 from other high-income countries, and 11 from low- or middle-income countries. Only 26 of the 78 studies reported a beneficial intervention effect for reduction of child ETS exposure, 24 of which were statistically significant. Of these 24 studies, 13 used objective measures of children's ETS exposure. We were unable to pinpoint what made these programmes effective. Studies showing a significant effect used a range of interventions: nine used in-person counselling or motivational interviewing; another study used telephone counselling, and one used a combination of in-person and telephone counselling; three used multi-component counselling-based interventions; two used multi-component education-based interventions; one used a school-based strategy; four used educational interventions, including one that used picture books; one used a smoking cessation intervention; one used a brief intervention; and another did not describe the intervention. Of the 52 studies that did not show a significant reduction in child ETS exposure, 19 used more intensive counselling approaches, including motivational interviewing, education, coaching, and smoking cessation brief advice. Other interventions consisted of brief advice or counselling (10 studies), feedback of a biological measure of children's ETS exposure (six studies), nicotine replacement therapy (two studies), feedback of maternal cotinine (one study), computerised risk assessment (one study), telephone smoking cessation support (two studies), educational home visits (eight studies), group sessions (one study), educational materials (three studies), and school-based policy and health promotion (one study). Some studies employed more than one intervention. 35 of the 78 studies reported a reduction in ETS exposure for children, irrespective of assignment to intervention and comparison groups. One study did not aim to reduce children's tobacco smoke exposure but rather sought to reduce symptoms of asthma, and found a significant reduction in symptoms among the group exposed to motivational interviewing. We found little evidence of difference in effectiveness of interventions between the well infant, child respiratory illness, and other child illness settings as contexts for parental smoking cessation interventions.

AUTHORS' CONCLUSIONS

A minority of interventions have been shown to reduce children's exposure to environmental tobacco smoke and improve children's health, but the features that differentiate the effective interventions from those without clear evidence of effectiveness remain unclear. The evidence was judged to be of low or very low quality, as many of the trials are at a high risk of bias, are small and inadequately powered, with heterogeneous interventions and populations.

Studying Impact of Nutrition on Growth (SING): a prospective cohort for comparing the health outcomes of young children with the dietary quality score

INTRODUCTION

This study aims to explore the prospective association between the dietary quality (DQ) of preschoolers and their health status in Hong Kong, with the body mass index as the main outcome variable.

METHODS AND ANALYSIS

This prospective cohort study has recruited 3539 children aged between 2 and 4 years old, with a follow-up period of 4 years. Their diet was reported by their parents by a 3-day food diary, and their body weight and height were measured yearly with standardised instruments. Questionnaires were administered to parents to acquire information of the children's prenatal development and dietary intake before their age of 2 years and of their baseline lifestyle and family backgrounds. The DQ was measured by the Healthy Eating Index as a continuous scale, while the exposure was defined as having a higher dietary quality score. Data were analysed using SPSS V.24. Linear and logistic regressions were used to examine the association of those predictive factors to the outcomes. Generalised estimating equations will be used to examine the longitudinal changes of the outcomes. A pilot study has been conducted, the preliminary results from which are presented in this cohort profile.

ETHICS AND DISSEMINATION

This study has been approved by the Joint Chinese University of Hong Kong and New Territory East Cluster Clinical Research Ethics Committee (CREC Ref No: 2013-632). Written informed consent was obtained from all subjects. The results will be published in due course.

Longitudinal Association between Obesity and Dental Caries in Adolescents

OBJECTIVE

To investigate the longitudinal association between obesity and dental caries among adolescents.

STUDY DESIGN

The present cohort study was conducted among a random sample of 12-year-old adolescents in Hong Kong. Two rounds of follow-up were performed when the participants were aged 15 and 18 years. A total of 668 participants were included at age 12 years, and 282 of them completed all 3 phases of data collection. Body mass index, waist circumference, waist-to-hip (WHR) ratio, waist-to-height ratio, and triceps skinfold thickness were measured as indices of obesity. Dental caries were assessed by the number of decayed, missing, and filled permanent teeth (DMFT).

RESULTS

The percentage of underweight adolescents increased significantly from 6.0% to 23.8% during the observation period (P <.001). Body mass index, waist circumference, waist-to-hip ratio, and waist-to-height ratio were related to frequency of tooth brushing at age 15 and 18 years. The prevalence of dental caries was 25.5%, 53.2%, and 62.1% at 12, 15 and 18 years, respectively. At age 18 years, mean DMFT of participants whose WHR at age 15 years was below the median value was 0.707 times (ie, 29.3%) lower than the DMFT of those whose WHR was above the median (P = .028). Participants with greater DMFT at age 15 demonstrated significantly increased probability of having WHR above the median (OR 1.135; 95% CI 1.01-1.28; P = .041) at age 18 years.

CONCLUSION

There is longitudinal association between central obesity and dental caries experience among adolescents aged 15-18 years.

Exposure to paternal tobacco smoking increased child hospitalization for lower respiratory infections but not for other diseases in Vietnam

Exposure to environmental tobacco smoke (ETS) is an important modifiable risk factor for child hospitalization, although its contribution is not well documented in countries where ETS due to maternal tobacco smoking is negligible. We conducted a birth cohort study of 1999 neonates between May 2009 and May 2010 in Nha Trang, Vietnam, to evaluate paternal tobacco smoking as a risk factor for infectious and non-infectious diseases. Hospitalizations during a 24-month observation period were identified using hospital records. The effect of paternal exposure during pregnancy and infancy on infectious disease incidence was evaluated using Poisson regression models. In total, 35.6% of 1624 children who attended follow-up visits required at least one hospitalization by 2 years of age, and the most common reason for hospitalization was lower respiratory tract infection (LRTI). Paternal tobacco smoking independently increased the risk of LRTI 1.76-fold (95% CI: 1.24-2.51) after adjusting for possible confounders but was not associated with any other cause of hospitalization. The population attributable fraction indicated that effective interventions to prevent paternal smoking in the presence of children would reduce LRTI-related hospitalizations by 14.8% in this epidemiological setting.

Rehospitalization of preterm infants according to the discharge risk level

PURPOSE

The rehospitalization rate of preterm infants is between 22 and 52% within the first year after discharge. The purpose of this study was to investigate the rehospitalization of preterm infants within 2 months following discharge, considering the level of risks originating from the infant, parents, and the social factors.

DESIGN AND METHODS

The sample was composed of 238 preterm infants and their parents. The data were collected with a Descriptive Information Form, the Post-Discharge Infant Follow-up Form, and the Neonatal Discharge Assessment Tool (N-DAT). Before discharge, the preterm infants were evaluated in terms of risky discharge via N-DAT consisting of the subscales Medical, Competencies, Risk factors, Resources, and Parenting. Discharge was determined as low, moderate, and high risk according to N-DAT total score. Two months after the discharge, rehospitalization of the infants was assessed. The data were evaluated via chi-square, Mann-Whitney U-test, and Fisher's exact test.

RESULTS

In the study, 39.9% of the preterm infants were rehospitalized within the 8 weeks following the discharge, with medical and/or surgical reasons. Medical problems such as pneumonia and acute bronchiolitis were ranked as the first cause for rehospitalization. As expected, according to the N-DAT scores, the rates of rehospitalization of infants who had been discharged with intermediate and high risk levels were found to be higher (p < .001) than the rates of those with low risk levels. Also, N-DAT Medical, Competencies, Risk factors, Resources, and Parenting subscale scores of the infants who were rehospitalized with medical problems were found to be higher at a statistically significant level than infants who were not rehospitalized (p < .001).

PRACTICE IMPLICATIONS

Nurses can help to minimize rehospitalization of infants by parental education, telephonic counseling, frequent observation, and home care support.

Maternal Age of Menarche and Blood Pressure in Adolescence: Evidence from Hong Kong's "Children of 1997" Birth Cohort

Background

Age of puberty has declined substantially in developed settings and is now declining in the rest of the world with economic development. Early age of puberty is associated with non-communicable diseases in adulthood, and may be a long-term driver of population health with effects over generations. In a non-Western setting, we examined the association of maternal age of menarche with blood pressure in late childhood/adolescence.

Methods

We used generalised estimating equations to estimate the adjusted association of maternal age of menarche with age-, sex- and height-adjusted blood pressure z-score from 10 to 16 years in Hong Kong’s population-representative birth cohort, “Children of 1997” (n = 8327). We also assessed whether associations were mediated by body mass index (BMI) or pubertal stage.

Results

Earlier maternal age of menarche was associated with higher systolic blood pressure in adolescence [-0.02 z-score per year older maternal age of menarche, 95% confidence interval (CI) -0.04 to -0.003]. The association of maternal age of menarche with systolic blood pressure was mediated by adiposity and/or pubertal stage at 11 years. Maternal age of menarche was not associated with diastolic blood pressure.

Conclusion

Earlier maternal age of puberty was associated with higher systolic blood pressure, largely mediated by adiposity, highlighting the importance of tackling childhood obesity as a public health priority in view of the secular trend of declining age of puberty.

Cost Analysis of Motivational Interviewing and Preschool Education for Secondhand Smoke Exposures

INTRODUCTION

This study determines if expenditures associated with implementing a combined motivational interviewing (MI) and Head Start-level education program (MI+Education), as compared to education alone, yield cost savings to society.

METHODS

Post hoc cost analyses were applied to a randomized controlled-trial of MI among predominantly African American, low-income caregivers of 330 Baltimore City Head Start students who reside with a smoker. The primary outcome was the cost savings of MI+Education from averted direct secondhand smoke exposure (SHSe)-related acute healthcare events and inferred indirect costs (work days lost, transportation and reduction in cigarettes smoked). The net direction of savings was defined by the sum of averted direct and indirect costs of the MI+Education intervention at 3, 6 and 12 months, benchmarked against the Education alone cohort at the equivalent time periods.

RESULTS

The costs saved by the MI+Education intervention, relative to Education alone, resulted in savings at solely the 12-month follow-up time point. Significant savings were appreciated from averted emergency department (ED) visits at 12 months ($4410; 95% simulation interval [SI]: $2241, $6626) for the MI+Education group. The total savings at 12 months ($2274; 95% SI: -3916, $8442) could not overcome additional program costs of implementing MI to Head Start-level education ($13 695; 95% SI: $11 250, $16 034).

CONCLUSIONS

This study is the first to examine the cost of either intervention on SHSe-attributed pediatric healthcare costs from a population level relevant for federal and community decision makers. Intervention costs could not be offset by short-term savings but a trend towards positive savings was appreciated 1 year after implementation.

IMPLICATIONS

Behavioral interventions are effective in reducing SHSe in children. However, many of these interventions are not implemented in community settings due to lack of resources and money. Behavioral strategies may be a cost-saving addition to the national initiatives to create smoke-free home environments. The long-term benefits of MI, as evidenced from cost savings from averted ED visits, appeared to show MI+Education to be a robust long-term strategy. The decrease of acute healthcare services at 12 months may be informative for policy decision makers seeking to allocate limited resources to reduce the usage of costly ED services and hospital readmissions.

Age at Onset of Puberty and Adolescent Depression: "Children of 1997" Birth Cohort

OBJECTIVE

Timing of onset of puberty has fallen, with profound and detrimental consequences for health. We examined the associations of earlier onset of puberty with the presence of depression in early to middle adolescence.

METHODS

The study examined prospective adjusted associations of age at onset of puberty, based on clinically assessed Tanner stage for breast/genitalia and pubic hair development, and self-reported presence of depression, assessed from the 9-item Patient Health Questionnaire on average at 13.6 years (n = 5795 [73%]). These factors were examined by using multivariable logistic regression in a population-representative Hong Kong Chinese birth cohort (ie, the "Children of 1997"). We also assessed whether associations varied according to gender.

RESULTS

Association of age at onset of breast/genitalia development with the presence of depression varied according to gender. Earlier onset of breast development was associated with higher risk of the presence of depression (odds ratio, 0.83 per 1 year increase in age of onset [95% confidence interval, 0.70 to 0.98]) adjusted for age, socioeconomic position, mother's place of birth, birth order, secondhand smoke exposure, parental age, survey mode, gender-specific birth weight z score, BMI z score at 7 years, and parental marital status. In boys, similarly adjusted, age at onset of genitalia development was unrelated to the presence of depression. Earlier age at onset of pubic hair development was unrelated to the presence of depression in girls and boys.

CONCLUSIONS

Early onset of breast development was associated with high risk of the presence of depression. Whether these findings are indicators of the effects of hormones or transient effects of social pressures remain to be determined.

Socioeconomic disparities in preterm birth and birth weight in a non-Western developed setting: evidence from Hong Kong's 'Children of 1997' birth cohort

BACKGROUND

Preterm birth (PTB), low birth weight and small-for-gestational age (SGA) are associated with lower socioeconomic position (SEP) in developed Western settings, but it is unclear if such disparities persist to the same extent elsewhere, and whether associations differ by measure of SEP used. Here, we assessed the association of SEP with PTB, birth weight and SGA in the recently developed non-Western setting of Hong Kong where few women smoke or use alcohol.

METHODS

We used multivariable logistic and linear regression to assess the associations of parental and neighbourhood SEP with PTB, birth weight and SGA among 8173 singleton births from the Hong Kong population-representative 'Children of 1997' birth cohort.

RESULTS

The only measure of SEP associated with PTB was type of housing adjusted for maternal age (p for trend 0.046). Highest paternal education had a small positive association with birth weight adjusted for gestational age (21 g, 95% CI 0.2 to 43 g for ≥grade 12 compared with ≤grade 9), as did residing in private compared with public housing (21 g, 95% CI 3 to 39 g). However, these associations did not persist after adjusting for mother's age. Lower neighbourhood Gini coefficient adjusted for mother's age was associated with a lower risk of SGA (OR 0.78, 95% CI 0.63 to 0.98). None of these associations remained after adjusting for multiple comparisons.

CONCLUSIONS

PTB, birth weight and SGA may be less clearly socially patterned in Hong Kong than other developed settings, highlighting the need for setting-specific interventions to prevent adverse birth outcomes.

Validity and reliability of the Neonatal Discharge Assessment Tool

PURPOSE

To investigate the reliability and validity of the Neonatal Discharge Assessment Tool (N-DAT) designed to assess risk factors related to infants' and parents' readiness for discharge to home.

DESIGN AND METHODS

The sample was composed of 238 high-risk preterm infants, born at gestational age of 24 to 37 weeks, and their parents. High scores on the N-DAT indicated higher risk for discharge of preterm infants and their parents. Psychometric analyses of the N-DAT included content validity, internal consistency reliability, and construct validity.

RESULTS

Content validity of the N-DAT items was supported by experts (content validity index = .98). Internal consistency reliability was supported by a Cronbach's alpha for the total instrument of .94. N-DAT total and subscale score correlations ranged from .42 to .89. Known-groups analysis indicated that infants born at <31 weeks' gestation and infants who were rehospitalized during 8 weeks after discharge had significantly higher N-DAT total and subscale scores than infants born at ≥31 weeks or not rehospitalized. Also, mothers who reported experiencing problems with infant care at home had significantly higher N-DAT Competencies subscale scores than mothers who did not report problems.

PRACTICE IMPLICATIONS

The N-DAT is a reliable and valid instrument to evaluate the risks related to discharge of preterm infants so that nurses can provide parents with the necessary knowledge, skills, and resources they need prior to discharge.

Gestational Age, Birthweight for Gestational Age, and Childhood Hospitalisations for Asthma and Other Wheezing Disorders

BACKGROUND

Preterm birth, early term birth, and low birthweight are associated with childhood wheezing disorders in developed Western settings, but observed associations could be confounded by socio-economic position. This study aims to clarify such associations in a developed non-Western setting with a different confounding structure.

METHODS

Using Cox regression, we examined the adjusted associations of gestational age and birthweight for gestational age with time to first public hospital admission for asthma, bronchitis, and bronchiolitis (International Classification of Diseases, Ninth Version Clinical Modification 466, 490, and 493) from 9 days to 12 years in a population-representative birth cohort of 8327 Chinese children in Hong Kong, a developed setting with less clear social patterning of prematurity or birthweight. Analyses were adjusted for infant and parental characteristics and socio-economic position.

RESULTS

Children born late preterm (34 to <37 weeks) had higher risk of hospitalisation for asthma and other wheezing disorders [hazard ratio (HR) 1.99, 95% confidence interval (CI) 1.48, 2.67] than children born full term (39 to <41 weeks). Early term births (37 to <39 weeks) had HR 1.01 (95% CI 0.84, 1.22), late term births (41 to <42 weeks) had HR 0.77 (95% 0.59, 1.01), and post-term births (≥42 weeks) had HR 0.56 (95% CI 0.32, 0.98). Large for gestational age was associated with lower risk of hospitalisation (HR 0.76, 95% CI 0.57, 0.99).

CONCLUSION

The association of preterm birth with childhood wheezing could be biologically mediated. We cannot rule out an association for early term births.

Mode of delivery and childhood hospitalizations for asthma and other wheezing disorders

BACKGROUND

Observationally, delivery by Caesarean section is associated with higher risk of childhood asthma and wheeze in developed Western settings, but associations are less consistent in other settings.

OBJECTIVE

To examine the association of mode of delivery with hospitalizations for asthma and other wheezing disorders in a developed non-Western setting with high rates of Caesarean section.

METHODS

Using Cox regression, we examined the adjusted association of mode of delivery with public hospital admissions for asthma, bronchitis, and bronchiolitis (International Classification of Diseases, Ninth Version Clinical Modification 466, 490 and 493) from 9 days to 12 years of age in a population-representative prospective birth cohort of 8327 Chinese children in Hong Kong. Confounders included sex, birth and parental characteristics, and socio-economic position (SEP).

RESULTS

Delivery by Caesarean section accounted for 27% of all births and was not clearly associated with hospitalizations for asthma and other wheezing disorders to 12 years [hazard ratio (HR) 1.11, 95% confidence interval (CI) 0.91 to 1.36] compared to vaginal delivery. Similarly, there were no clear associations to 2 years (HR 1.07, 95% CI 0.83 to 1.38) or 6 years (HR 1.12, 95% CI 0.91 to 1.37), although we cannot rule out residual confounding by SEP.

CONCLUSIONS AND CLINICAL RELEVANCE

We cannot rule out an association, but our findings suggest that the observed associations of delivery by Caesarean section with childhood wheezing disorders may vary with setting and may not be biologically mediated. Further studies with different designs are needed to clarify the role of the microbiome and mode of delivery in the aetiology of asthma and other childhood wheezing disorders.

Breastfeeding and childhood hospitalizations for asthma and other wheezing disorders

PURPOSE

Observationally in Western settings, breastfeeding is associated with less childhood wheezing disorders but may be confounded by socioeconomic position. We examined the association of breastfeeding with asthma and other wheezing disorders in a developed non-Western setting with unique social patterning of breastfeeding.

METHODS

Using Cox regression, we examined the adjusted associations of breastfeeding with public hospital admissions for asthma, bronchitis, and bronchiolitis (International Classification of Diseases, Ninth Version. Clinical Modification: 466, 490, and 493) from 3 months to 12 years in a population-representative birth cohort of 8327 Hong Kong Chinese children.

RESULTS

We did not find an association of exclusive breastfeeding for 3 months or more, compared with never breastfeeding, with hospitalization for asthma, bronchitis, and bronchiolitis to 12 years (hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.63-1.25) nor for partial breastfeeding for any length of time or exclusive breastfeeding for less than 3 months (HR, 1.02; 95% CI, 0.86-1.21), adjusted for infant and parental characteristics and socioeconomic position. We also did not find an association of exclusive breastfeeding for 3 months or more with hospitalization for asthma only (International Classification of Diseases, Ninth Version. Clinical Modification: 493) (HR, 1.27; 95% CI, 0.82-1.98).

CONCLUSIONS

In a large population-representative Chinese birth cohort, we did not find an association of breastfeeding with childhood hospitalizations for asthma and other wheezing disorders.

The Association of Infant Growth Patterns with Adiposity in Adolescence: Prospective Observations from Hong Kong's 'Children of 1997' Birth Cohort

BACKGROUND

The role of infant growth in adiposity remains unclear.

METHODS

We used multivariable linear regression, with inverse probability weighting and multiple imputation to account for loss to follow-up, in a population-representative Chinese birth cohort, 'Children of 1997' in Hong Kong, to examine, in terms births, the adjusted association of infant (birth to 12 months) weight growth trajectories with body mass index (BMI) (n = 6861, 88% follow-up), waist-to-height ratio (WHtR), and waist-to-hip ratio (WHR) (n = 5398, 69% follow-up) at ∼ 14 years.

RESULTS

Infant weight growth trajectories had graded associations with adolescent BMI and WHtR but not with WHR, such that compared with adolescents born light with slow infant growth, adolescents born heavy with fast infant growth had higher BMI z-score [0.60, 95% confidence interval (CI) 0.49, 0.70], higher WHtR z-score (0.17, 95% CI 0.08, 0.26) but similar WHR z-score (-0.02, 95% CI -0.11, 0.08), adjusted for sex, gestational age, parental education, parental BMI, parental height, and parental place of birth.

CONCLUSIONS

Varying associations of infant growth with different adiposity measures suggest a complex role of infant growth in long-term health, perhaps because infant growth, or its underlying drivers, influences build and body composition as well as adiposity.

Adiposity and early adolescent emotional/behavioral problems

OBJECTIVE

To examine whether life course adiposity is associated with emotional/behavioral problems in a non-Western developed setting with little social patterning of adiposity.

STUDY DESIGN

In a prospective, population-representative Chinese birth cohort, "Children of 1997," multivariable partial least squares regression was used to assess the adjusted associations of birth weight z-score, body mass index (BMI) z-scores at ages 3 months, 9 months, 3 years, 7 years, 9 years, and BMI z-score changes with emotional/behavioral problems at ∼ 11 years of age, assessed from the Chinese version of the Revised Parent's Rutter Scales.

RESULTS

Rutter score was available for 4976 (62.8% follow-up). Birth weight z-score, BMI z-scores at ages 3 months, 9 months, 3 years, 7 years, 9 years, and successive BMI z-scores changes had little association with Rutter score or subscores at ∼ 11 years of age, adjusted for socioeconomic position, although birth weight was negatively associated with specifically hyperactivity.

CONCLUSIONS

In a developed, non-Western setting, we did not find adiposity be a factor in the development of emotional/behavioral problems in early adolescence. Although, we cannot rule out the possibility of residual confounding by genetic or familial factors, our results suggest that the reported associations may be contextually specific rather than biologically based. Whether lower birth weight is associated with hyperactivity in early adolescence needs to be confirmed or refuted in other suitable settings.

Secondhand smoke exposure, parental depressive symptoms and preschool behavioral outcomes

Little is known about the association of secondhand smoke (SHS) exposure and behavioral conditions among preschoolers. A cross-sectional analysis was used to examine billing and pharmacy claims from November 2004 to June 2012 linked to medical encounter-level data for 2,441 children from four pediatric community health clinics. Exposure to SHS was associated with attention deficit-hyperactivity disorder/ADHD and disruptive behavior disorder/DBD after adjusting for potential confounding factors. Assessment of exposure to SHS and parental depressive symptoms in early childhood may increase providers' ability to identify children at higher risk of behavioral issues and provide intervention at the earliest stages.

Promoting smoking cessation among parents: effects on smoking-related cognitions and smoking initiation in children

BACKGROUND

Parental smoking is associated with an increased risk of smoking among youth. Epidemiological research has shown that parental smoking cessation can attenuate this risk. This study examined whether telephone counselling for parents and subsequent parental smoking cessation affect smoking-related cognitions and smoking initiation among children of smoking parents.

METHODS

Data of a two-arm randomized controlled trial were used in which 512 smoking parents were recruited into cessation support through their children's primary schools. After the baseline assessment, smoking parents were randomly assigned to tailored telephone counselling or a standard self-help brochure. Parental cessation was measured as 6-month prolonged abstinence at the 12-month follow-up. Children's smoking-related cognitions and smoking initiation were examined at 3-month, 12-month, and 30-month follow-up.

RESULTS

No statistical evidence was found that children of parents who received telephone counselling tailored to smoking parents or children of parents who achieved prolonged abstinence differ in smoking-related cognitions (i.e., smoking outcome expectancies, perceived safety of smoking, self-efficacy to refrain from smoking, susceptibility to smoking) or smoking initiation rate on any follow-up assessment.

CONCLUSIONS

This study is the first to examine the effects of an evidence-based smoking cessation treatment for parents and treatment-induced parental smoking cessation on cognitive and behavioural outcomes among children. Although descriptive statistics showed lower smoking initiation rates among children of parents who achieved prolonged abstinence, there was no statistical evidence that telephone counselling tailored to parents or treatment-induced parental smoking cessation affects precursors of smoking or smoking initiation among youth.

Family and carer smoking control programmes for reducing children's exposure to environmental tobacco smoke

BACKGROUND

Children's exposure to other people's cigarette smoke (environmental tobacco smoke, or ETS) is associated with a range of adverse health outcomes for children. Parental smoking is a common source of children's exposure to ETS. Older children are also at risk of exposure to ETS in child care or educational settings. Preventing exposure to cigarette smoke in infancy and childhood has significant potential to improve children's health worldwide.

OBJECTIVES

To determine the effectiveness of interventions aiming to reduce exposure of children to ETS.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialized Register and conducted additional searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PsycINFO, EMBASE, CINAHL, ERIC, and The Social Science Citation Index & Science Citation Index (Web of Knowledge). Date of the most recent search: September 2013.

SELECTION CRITERIA

Controlled trials with or without random allocation. Interventions must have addressed participants (parents and other family members, child care workers and teachers) involved with the care and education of infants and young children (aged 0 to 12 years). All mechanisms for reduction of children's ETS exposure, and smoking prevention, cessation, and control programmes were included. These include health promotion, social-behavioural therapies, technology, education, and clinical interventions.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies and extracted data. Due to heterogeneity of methodologies and outcome measures, no summary measures were possible and results were synthesised narratively.

MAIN RESULTS

Fifty-seven studies met the inclusion criteria. Seven studies were judged to be at low risk of bias, 27 studies were judged to have unclear overall risk of bias and 23 studies were judged to have high risk of bias. Seven interventions were targeted at populations or community settings, 23 studies were conducted in the 'well child' healthcare setting and 24 in the 'ill child' healthcare setting. Two further studies conducted in paediatric clinics did not make clear whether the visits were to well or ill children, and another included both well and ill child visits. Thirty-six studies were from North America, 14 were in other high income countries and seven studies were from low- or middle-income countries. In only 14 of the 57 studies was there a statistically significant intervention effect for child ETS exposure reduction. Of these 14 studies, six used objective measures of children's ETS exposure. Eight of the studies had a high risk of bias, four had unclear risk of bias and two had a low risk of bias. The studies showing a significant effect used a range of interventions: seven used intensive counselling or motivational interviewing; a further study used telephone counselling; one used a school-based strategy; one used picture books; two used educational home visits; one used brief intervention and one study did not describe the intervention. Of the 42 studies that did not show a significant reduction in child ETS exposure, 14 used more intensive counselling or motivational interviewing, nine used brief advice or counselling, six used feedback of a biological measure of children's ETS exposure, one used feedback of maternal cotinine, two used telephone smoking cessation advice or support, eight used educational home visits, one used group sessions, one used an information kit and letter, one used a booklet and no smoking sign, and one used a school-based policy and health promotion. In 32 of the 57 studies, there was reduction of ETS exposure for children in the study irrespective of assignment to intervention and comparison groups. One study did not aim to reduce children's tobacco smoke exposure, but rather aimed to reduce symptoms of asthma, and found a significant reduction in symptoms in the group exposed to motivational interviewing. We found little evidence of difference in effectiveness of interventions between the well infant, child respiratory illness, and other child illness settings as contexts for parental smoking cessation interventions.

AUTHORS' CONCLUSIONS

While brief counselling interventions have been identified as successful for adults when delivered by physicians, this cannot be extrapolated to adults as parents in child health settings. Although several interventions, including parental education and counselling programmes, have been used to try to reduce children's tobacco smoke exposure, their effectiveness has not been clearly demonstrated. The review was unable to determine if any one intervention reduced parental smoking and child exposure more effectively than others, although seven studies were identified that reported motivational interviewing or intensive counselling provided in clinical settings was effective.

Racial, Ethnic, and Language Disparities in Children's Exposure to Secondhand Smoke

Race and ethnicity affect children's risk of secondhand smoke exposure. However, little is known about how race and language preference impact parents' self-reported smoking and stopping smoking rates. We analyzed data for 16,523 children aged 0-11 years from a pediatric computer decision support system (Child Health Improvement through Computer Automation [CHICA]). CHICA asks families in the waiting room about household smokers. We examined associations between race, insurance, language preference, and household smoking and reported stopping smoking rates using logistic regression. Almost a quarter (23%) of the children's families reported a smoker at home. Hispanic children are least likely (odds ratio [OR]: 0.17, confidence interval [CI]: 0.12-0.24) to have secondhand smoke exposure when compared to African American and white children, as were those with private insurance (OR: 0.52, CI: 0.43-0.64) or no insurance (OR: 0.79, CI: 0.71-0.88) compared to publicly insured. Children from English speaking families were more likely (OR: 1.55, CI: 1.24-1.95) to have secondhand smoke exposure compared to Spanish speaking families. Among smoking families, 30% reported stopping smoking subsequently. Stopping rates were higher in Hispanic (OR: 3.25, CI: 2.06-5.13) and African American (OR: 1.39, CI: 1.01-1.91) families compared to white children's families. Uninsured families were less likely than publicly insured families to report stopping smoking (OR: 0.76, CI: 0.63-0.92). English speaking families were less likely (OR: 0.56, CI: 0.41-0.75) to report stopping smoking compared to Spanish speaking even in a subgroup analyses of Hispanic families (OR: 0.55, CI: 0.39-0.76). In our safety net practices serving children predominantly on public insurance, Spanish speaking families reported the lowest risk of secondhand smoke exposure in children and the highest rate of stopping smoking in the household. Hispanic families may have increasing secondhand exposure and decreasing rates of stopping smoking as they acculturate.

Secondhand smoke and asthma: what are the effects on healthcare utilization among children?

OBJECTIVE

This study aims to examine the associations between asthma, secondhand smoke exposure and healthcare utilization in a nationally representative sample of children.

METHODS

Data from 5686 children aged 0-11 years were analyzed. Healthcare utilization, asthma diagnosis and demographic information came from the 2001 and 2006 Medical Expenditure Panel Surveys. Secondhand smoke exposure was measured during the 2000 and 2005 National Health Interview Surveys. Multivariable regression models were used to determine the association between secondhand smoke exposure, asthma diagnosis and healthcare utilization (hospitalizations, emergency department visits, outpatient visits and prescription medication use).

RESULTS

Asthma modified the relationship between secondhand smoke exposure and hospitalizations, as exposure more than doubled the odds of hospitalization among children with asthma but had no effect on children without asthma. Secondhand smoke exposure increased the odds by 37% of emergency room visits (P<0.001), but was not associated with outpatient visits or medication use. Children with asthma had a higher odds of utilizing all healthcare services (P<0.001).

CONCLUSIONS

Secondhand smoke exposure was associated with a greater utilization of hospitals and emergency departments, and the effect on hospitalizations was most pronounced among children with asthma. Reducing secondhand smoke exposure would help to reduce the burden on the healthcare system, especially among children with asthma.

Mode of delivery and adiposity: Hong Kong's "Children of 1997" birth cohort

PURPOSE

To examine whether mode of delivery was associated with childhood adiposity in a developed non-Western context.

METHODS

We used generalized estimating equations to estimate the association of mode of delivery (vaginal or cesarean) with body mass index (BMI) z-score and overweight (including obesity) from 3 months to 13 years, in 7809 term birth (94% follow-up) from a population-representative Chinese birth cohort, "Children of 1997." We used multiple imputation for missing data.

RESULTS

The cesarean section rate (26%) was higher for children born in private hospitals, with lower gestational age, lower birth order, higher maternal age, higher maternal BMI, and higher family socioeconomic position. Cesarean section was not associated with BMI z-score from 3 months to 13 years (mean difference, 0.03; 95% confidence interval, -0.02 to 0.09) or overweight from 3 years to 13 years (odds ratio, 0.98; 95% confidence interval, 0.77 to 1.25) after adjusting for infant and maternal characteristics and family socioeconomic position.

CONCLUSIONS

In a non-Western developed setting, mode of delivery was not clearly associated with BMI or overweight (including obesity) into late childhood. From a public health perspective, the role of mode of delivery and its mechanistic pathway in the current burgeoning epidemic of obesity needs to be clarified.

Secondhand smoke exposure and health services use among adolescent current smokers

Background

To investigate the associations of secondhand smoke (SHS) exposure with medical consultation and hospitalisation among adolescents in Hong Kong.

Methods

A total of 35827 secondary 1 (US grade 7) to secondary 5 students from 85 randomly selected schools completed an anonymous questionnaire on smoking, SHS at home, SHS outside home, medical consultation in the past 14 days, hospitalisation in the past 12 months, and socio-demographic characteristics. Current smoking was defined as any smoking in the past 30 days. SHS exposure was classified as none (reference), 1–4 and 5–7 days/week. Logistic regression yielded adjusted odds ratios (AORs) for medical consultation and hospitalisation in relation to SHS exposure at home and outside home in current smokers. Analyses were also done among never-smokers for comparison.

Results

Among all students, 15.9% had medical consultation and 5.2% had been hospitalised. Any SHS exposure at home was associated with AORs (95% CI) for medical consultation and hospitalisation of 1.69 (1.14–2.51) and 2.85 (1.47–5.52) in current smokers, and 1.03 (0.91–1.15) and 1.25 (1.02–1.54) in never-smokers, respectively, (P<0.01 for interaction between smoking status and SHS exposure at home). SHS exposure outside home was generally not associated with medical consultation and hospitalisation in smokers and never-smokers.

Conclusions

SHS exposure at home was associated with health services use among adolescent current smokers. Adolescent smokers should be aware of the harm of SHS in addition to that from their own smoking. The evidence helps health care professionals to advise adolescent smokers to avoid SHS exposure and stop smoking.

Timing of solid food introduction and obesity: Hong Kong's "children of 1997" birth cohort

BACKGROUND

Some observational studies in Western settings show that early introduction of solid food is associated with subsequent obesity. However, introduction of solid food and obesity share social patterning. We examined the association of the timing of the introduction of solid food with BMI and overweight (including obesity) into adolescence in a developed non-Western setting, in which childhood obesity is less clearly socially patterned.

METHODS

We used generalized estimating equation models to estimate the adjusted associations of the timing of the introduction of solid food (<3, 3-4, 5-6, 7-8, and >8 months) with BMI z score and overweight (including obesity) at different growth phases (infancy, childhood, and puberty) in 7809 children (88% follow-up) from a Chinese birth cohort, "Children of 1997." We assessed if the associations varied with gender or breastfeeding. We used multiple imputation for missing exposure and confounders.

RESULTS

The introduction of solid food at <3 months of age was associated with lower family socioeconomic position (SEP) but was not clearly associated with BMI or overweight (including obesity) in infancy [mean difference in BMI z score: 0.01; 95% confidence interval (CI): -0.14 to 0.17], childhood (0.14; 95% CI: -0.11 to 0.40), or at puberty (0.22; 95% CI: -0.07 to 0.52), adjusted for SEP and infant and maternal characteristics.

CONCLUSIONS

In a non-Western developed setting, there was no clear association of the early introduction of solid food with childhood obesity. Together with the inconsistent evidence from studies in Western settings, this finding suggests that any observed associations might simply be residual confounding by SEP.

Lifetime growth and blood pressure in adolescence: Hong Kong's "Children of 1997" birth cohort

OBJECTIVES

Blood pressure tracks from adolescence to adulthood and is positively associated with low birth weight and faster infant growth. Most observations are from Western populations; it is unclear whether these are biologically based or contextually specific. We examined the associations of growth with blood pressure in adolescence.

METHODS

Multivariable partial least squares regression was used to assess the associations of growth to ~11 years with blood pressure at ~11 years in 5813 term births from Hong Kong's Children of 1997 birth cohort. Growth was considered as gender- and age-specific z-scores for birth weight, BMI, and length at 3 months; change in z-scores for BMI and height at 3 to 9 months, 9 to 36 months, 3 to 7 years, and 7 to 11 years; and BMI and height at 11 years.

RESULTS

Birth weight was weakly inversely associated with systolic blood pressure in girls -0.58 mm Hg 95% confidence interval -1.05 to -0.12 (boys -0.21, -0.71 to 0.30). Childhood growth, particularly linear growth at 7 to 11 years (girls: 1.27, 0.56 to 1.98; boys 2.11, 1.39 to 2.83), as well as current height (girls: 2.40, 2.04 to 2.76, boys: 2.65, 2.29 to 3.01) and BMI (girls: 2.72, 2.35 to 3.09, boys: 2.72, 2.09 to 3.36) were associated with higher systolic blood pressure. Diastolic blood pressure was also positively associated with current size.

CONCLUSIONS

In the first study to examine simultaneously the role of pre- and postnatal growth in adolescent blood pressure, the role of late childhood growth predominated.

The role of dairy products and milk in adolescent obesity: evidence from Hong Kong's "Children of 1997" birth cohort

Background

Observational studies, mainly from Western populations, suggest dairy consumption is inversely associated with adiposity. However, in these populations the intake range is limited and both diet and obesity may share social patterning. Evidence from non-Western developed settings with different social patterning, is valuable in distinguishing whether observed associations are biologically mediated or socially confounded.

Objective

To examine the associations of milk or other dairy product consumption with adolescent obesity.

Methods

We used multivariable linear regression models to examine the associations of milk or other dairy product consumption, obtained from a food frequency questionnaire, at 11 years with body mass index (BMI) z-scores at 13 years and waist hip ratio (WHR) at 11 years, in 5,968 adolescents from a Chinese birth cohort, comprising 88% of births in April and May 1997. We used multiple imputation for missing exposures and confounders.

Results

Only 65.7% regularly consumed milk and 72.4% other dairy products. Milk and other dairy product consumption was positively associated with socio-economic position but not with BMI z-score or WHR, with or without adjustment for sex, mother’s birthplace, parental education, physical activity and other food consumption.

Conclusions

The lack of association of milk and other dairy product consumption with adiposity in a non-Western setting was not consistent with the majority of evidence from Western settings. Observed anti-obesigenic effects in Western settings may be due to socially patterned confounding.

The prevalence and effects of environmental tobacco smoke exposure among inner-city children: lessons for pediatric residents

PURPOSE

To determine the prevalence of environmental tobacco smoke (ETS) exposure, to explore the relationship between ETS exposure and the use of health services, and to examine the degree to which pediatric residents document ETS exposure status and counsel parents.

METHOD

In 2006, the authors recruited dyads of children (0-12 years old) and their mothers from an inner-city pediatric group practice clinic. Mothers completed a survey, and the authors searched the children's medical charts. The authors compared ETS-exposed children with nonexposed children using chi-square, t test, and ANOVA analyses. They also ran logistic regression analyses to examine the relationship between the use of health services and selected child and maternal variables.

RESULTS

More than 60% (142/232) of children were exposed to ETS, and more than 69% (99/142) of those children had a mother who smoked. ETS exposure significantly predicted the overall number of sick visits, even after controlling for sociodemographic confounders (odds ratio = 7.44; 95% confidence internal = 1.21-44.55). About 80% (187/232) of mothers reported that their child's pediatrician had counseled them on the dangers of ETS exposure. Less than half (105/232) of the children's charts included their ETS exposure status.

CONCLUSIONS

Although pediatric residents often counsel parents on the dangers of ETS exposure, educators should teach residents to regard ETS exposure status as a fifth vital sign. By screening for and documenting ETS exposure status, residents can identify at-risk children and parents, who could benefit from counseling.

Small for gestational age and age at puberty: evidence from Hong Kong's "Children of 1997" birth cohort

The predictive-adaptive response paradigm postulates that slow fetal growth advances puberty as a life-history strategy for reproductive success, when constraints on postnatal growth are minimal. The authors examined the association of birth weight for gestational age and small for gestational age (SGA) status (birth weight for gestational age <10th percentile, 6.9%) with clinically assessed age at onset of Tanner stage II in a non-Western developed population using interval-censored regression in 7,366 children (89% follow-up) from a population-representative Chinese birth cohort, "Children of 1997" in Hong Kong. Neither SGA status nor birth weight z score for gestational age was associated with age at onset of puberty, adjusted for sex, mother's place of birth, parental height, income, and parental education. Greater childhood height and linear growth were associated with younger age at onset of puberty. SGA status was associated with earlier puberty after adjustment for childhood height (time ratio = 0.984, 95% confidence interval: 0.972, 0.995) but later puberty after adjustment for linear growth (time ratio = 1.017, 95% confidence interval: 1.005, 1.030). In this developed city of China, SGA status was not associated with timing of puberty. However, the observation may be contextually specific depending on how other attributes, such as childhood growth, differ between SGA and other children.

The importance of social networks on smoking: perspectives of women who quit smoking during pregnancy

While up to 45% of women quit smoking during pregnancy, nearly 80% return to smoking within a year after delivery. Interventions to prevent relapse have had limited success. The study objective was to understand what influences return to smoking after pregnancy among women who quit smoking during pregnancy, with a focus on the role of social networks. We conducted in-depth, semi-structured interviews during the postpartum hospital stay with women who quit smoking while pregnant. Over 300 pages of transcripts were analyzed using qualitative methods to identify common themes. Respondents [n = 24] were predominately white (63%), had at least some college education (54%) and a mean age of 26 years (range = 18-36). When reflecting on the experience of being a smoker who quit smoking during pregnancy, all participants emphasized the importance of their relationships with other smokers and the changes in these relationships that ensued once they quit smoking. Three common themes were: (1) being enmeshed in social networks with prominent smoking norms (2) being tempted to smoke by members of their social networks, and (3) changing relationships with the smokers in their social networks as a result of their non-smoking status. We found that women who quit smoking during pregnancy found themselves confronted by a change in their social network since most of those in their social network were smokers. For this reason, smoking cessation interventions may be most successful if they help women consider restructuring or reframing their social network.

Foetal exposure to maternal passive smoking is associated with childhood asthma, allergic rhinitis, and eczema

Objective. We examined the hypothesis that foetal exposure to maternal passive smoking is associated with childhood asthma, allergic rhinitis, and eczema. Methods. The study was a population-based cross-sectional survey of Hong Kong Chinese children aged ≤14 years carried out in 2005 to 2006. Results. Foetal exposure to maternal passive smoking was significantly associated with wheeze ever (OR 2.05; 95% CI 1.58–2.67), current wheeze (OR 2.06; 95% CI 1.48–2.86), allergic rhinitis ever (OR 1.22; 95% CI 1.09–1.37), and eczema ever (OR 1.61; 95% CI 1.38–1.87). Foetal exposure to maternal active smoking was significantly associated with asthma ever (OR 2.10; 95% CI 1.14–3.84), wheeze ever (OR 2.46; 95% CI 1.27–4.78), and current wheeze (OR 2.74; 95% CI 1.24–6.01) but not with allergic rhinitis ever (OR 1.01; 95% CI 0.70–1.46) or eczema ever (OR 1.38; 95% CI 0.87–2.18). The dose response relationship between wheeze ever and current wheeze with increasing exposure, from no exposure to maternal passive smoking and then to maternal active smoking, further supports causality. Conclusion. There is significant association between foetal exposure to maternal passive smoking and maternal active smoking with childhood asthma and related atopic illnesses. Further studies are warranted to explore the potential causal relationship.

Premature birth and age at onset of puberty

BACKGROUND

Premature birth is associated with poor metabolic health in both sexes, potentially via earlier pubertal timing.

METHODS

We examined the associations of gestational age and premature birth (< 37 weeks gestation) with age at onset of puberty (Tanner stage II for breast or genitalia development). We used interval-censored survival analyses in 3963 boys and 3403 girls (93% follow-up) in a population-representative Chinese birth cohort, "Children of 1997," comprising 88% of births in Hong Kong in April and May 1997. We also examined whether the associations varied with sex or with height or body mass index (BMI) at 7 years.

RESULTS

Premature girls reached puberty about 4 months later than girls with ≥ 41 weeks' gestation (time ratio = 1.04 [95% confidence interval = 1.01-1.06]), adjusted for mother' age of menarche, mother's place of birth, and smoking during pregnancy. Gestational age was not associated with onset of puberty in boys (test for interaction by sex, P < 0.01). None of these associations was altered by adjustment for socioeconomic position or varied with childhood height or BMI.

CONCLUSIONS

Premature birth was not related to earlier onset of puberty; instead, premature girls had later onset of puberty. Thus, the association between premature birth and subsequent cardiovascular risk is probably not mediated through the timing of pubertal onset. It is unclear whether onset, duration, or tempo of puberty is more relevant to the detrimental consequences of early puberty. Further studies investigating intrauterine, infant, and childhood influences on the duration and tempo of puberty may help unravel the early origins of cardiovascular diseases.

Factors associated with rehospitalizations of very low birthweight infants: impact of a transition home support and education program

OBJECTIVE

To determine the effects of a transition-home education and support program, BPD, and health insurance type on VLBW infant rehospitalizations at 3 and 7 months corrected age. It was hypothesized that the transition-home program would be associated with decreased rehospitalizations between Phase 1 and 2, and public health insurance and BPD would be associated with increased rehospitalizations.

METHODS

274 infants with birth weight <1500 g were enrolled in two successive years of a transition-home program (Phase 1-start-up) and (Phase 2-full implementation) and followed to 7 months CA.

RESULTS

The Phase 2 rehospitalization rates were lower but not statistically significant at both 3 months (20% and 15%; p=0.246), and 7 months (24% and 17%; p=0.171). Infants with public insurance had twice as many rehospitalizations by 3 months (28% versus 11%; p=0.018) in Phase 1. In regression analyses the intervention effects did not achieve significance for the cohort at 3 months (OR=0.63; CI=0.33 to 1.20) or 7 months (OR=0.61; CI=0.33 to 1.13). BPD and public insurance did not reach significance in the models whereas siblings were significantly associated with increased odds of rehospitalization. In subgroup analyses for infants on pubic health insurance the intervention significantly decreased the odds of rehospitalization between Phase 1 and 2(OR=0.43; CI=0.19 to 0.96) at 3 months.

CONCLUSIONS

Our findings suggest that a transition-home program may be beneficial to reduce the rehospitalization rate for VLBW infants, and infants on public insurance may derive greater benefit.

A qualitative study of postpartum mothers' intention to smoke

BACKGROUND

Many women stop smoking during pregnancy. Factors associated with relapse are known, but no intervention prevents the return to smoking among pregnant women. The objective of this study was to determine why women return to smoking after prolonged abstinence during pregnancy by examining mothers' intention to smoke at the time of delivery and the perceptions that shape their intention.

METHODS

We conducted in-depth, semi-structured interviews during their postpartum hospital stay with 24 women who stopped smoking while pregnant. We asked participants whether they intended to resume smoking after pregnancy and why. Transcripts were analyzed using grounded theory-based qualitative methods to identify themes.

RESULTS

Participants ranged in age from 18 to 36 years, and 63 percent were white. Three themes emerged from the interviews with the mothers: 1) they did not intend to return to smoking but doubted whether they would be able to maintain abstinence; 2) they believed that it would be possible to protect their newborns from the harms of cigarette smoke; and 3) they felt that they had control over their smoking and did not need help to maintain abstinence after pregnancy.

CONCLUSIONS

Although most participants did not intend to resume smoking, their intentions may be stymied by their perceptions about second-hand smoke and by their overestimation of their control over smoking. Further study should quantify these barriers and determine their evolution over the first year after pregnancy with the goal of informing more successful, targeted interventions.

Effect of diesel exhaust particles on human middle ear epithelial cells

OBJECTIVE

In the present study, we investigate whether diesel exhaust particles (DEPs) cause cytotoxicity and induce inflammation or increase the expression of mucin in immortalized human middle ear epithelial cell lines (HMEECs). Several publications have shown an association between traffic-related air pollutants and otitis media. Additionally, DEP have been shown to cause inflammation and an allergic response in the airways.

METHODS

Cell viability following DEP treatment was investigated in HMEECs using the MTT assay. We measured the expression of the inflammatory cytokines TNF-α and COX-2 and the mucin genes MUC5AC and MUC5B using semiquantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting.

RESULTS

Cell viability tests showed that exposure to more than 80 μg/mL of DEP caused a decrease in cell viability. DEP exposure also increased the expression of MUC5AC, but did not induce the expression of MUC5B in HMEECs.

CONCLUSION

DEP decreased cell viability, induced an inflammatory response, and increased mucin gene expression in HMEECs. These findings support the hypothesis that environmental diesel exposure is a risk factor for otitis media.

Planning the Location of Stop Smoking Services at the Local Level: A Geographic Analysis

Smoking is one of the major causes of premature death and its negative effects on a person's health are a global issue. Therefore, the United Kingdom has introduced new policies aimed at reducing the proportion of smokers from 26% in 2005 down to 21% by 2010. One mechanism to meet this policy target is the provision of stop smoking services. This article aims to estimate the Leeds smoking population at the small area level and especially to highlight the distribution of hard-to-reach groups such as heavy smokers (> 20 cigarettes/day) and pregnant women who smoke. Then optimal location strategies are discussed in relation to stop smoking services. The findings show the importance of adding a spatial component to find out where the smoking population or specific subgroups of smokers are to support policymakers or healthcare planners who are responsible for the planning process of the services.

Predictors of spontaneous smoking cessation among Chinese men whose wives are pregnant

This is an exploratory study to identify the predictors that Chinese men will spontaneously quit smoking during their wives' pregnancy. Smoking husbands who accompanied their non-smoking pregnant wives to an antenatal clinic were invited to complete a questionnaire soliciting information regarding their smoking behaviours, perceptions of support received from their wives, and motivating factors for quitting smoking. A total of 74 men were recruited. Two-thirds (67.6%) were daily smokers, had started smoking under the age of 18 (66.2%), and smoked 6-15 cigarettes (48.6%) a day. Nearly one-third of the smoking husbands (n = 50, 67.6%) reported that their wife was the person who provided them with the necessary main support in quitting. Nearly a quarter (18 out of 74, 24.3%) of the husbands indicated that they quit smoking during their wives' pregnancy. Those more likely to quit were the 'occasional smokers' (61.1% vs. 38.9%), those who craved cigarettes a few hours after getting up (0% vs. 100%), those who were confident in their ability to quit (77.8% vs. 22.2%), and those who had previously attempted to quit (88.9% vs. 11.1%). The level of negative support from wives to quit smoking was significantly related to men's quitting (55.6% vs. 44.4%). The results of this study identified the husbands most likely to spontaneously quit smoking during their wives' pregnancy as those who were occasional smokers, were confident about smoking cessation, and reported their wives as being bothered by smoke.

Early life infections and onset of puberty: evidence from Hong Kong's children of 1997 birth cohort

As economic development increases, puberty occurs at younger ages, and this could contribute to an increase in the incidence of cardiovascular diseases and hormone-related cancers. The factors that determine pubertal timing are poorly understood. The growth axis that is active during puberty is active in the first 6 months of life and interacts with the immune system. The authors examined whether prior infections, proxied by number of hospital admissions for infections at different ages, were associated with age at pubertal onset (Tanner stage II) using interval-censored regression in the Children of 1997 cohort, which is a population-representative Chinese birth cohort (n = 7,527). Mediation by growth was also examined. Girls, but not boys, who were hospitalized for infections at least twice in the first 6 months of life experienced pubertal onset about 8 months later (mean = 10.3 years, time ratio = 1.08, 95% confidence interval: 1.04, 1.12) than did those without such hospitalizations (mean = 9.6 years) after adjustment for infant characteristics and socioeconomic position (sex interaction: P = 0.02). There were no such associations for infections at 6 months to ≤8 years of age. Growth did not mediate the association. Early infectious morbidity in girls may be associated with later puberty, perhaps via suppression of the gonadotropic axis. The lowering of the number of infections in early life that accompanies economic development could be an additional factor that contributes to earlier puberty.

Is informal child care associated with childhood obesity? Evidence from Hong Kong's "Children of 1997" birth cohort

BACKGROUND

In Western populations, informal child care is associated with childhood obesity. However, informal child care and obesity share social patterning making evidence from other settings valuable.

METHODS

We used multivariable linear and logistic regression models to estimate the association of child care at 6 months and at 3, 5 and 11 years with body mass index (BMI) z-score and overweight (including obesity) at 11 years in a Hong Kong Chinese birth cohort. We assessed whether associations varied with sex or socio-economic position (SEP). We used multiple imputation for missing exposures and confounders.

RESULTS

Of the original 8327 cohort members, 7933 are alive, participating and living in Hong Kong. At ~11 years, 6796 had their BMI clinically assessed. Higher SEP was associated with informal care. After imputation, informal care at each of 3, 5 or 11 years was separately associated with higher BMI z-score [3 years 0.10, 95% confidence interval (CI) 0.03-0.18, 5 years 0.12, 95% CI 0.04-0.21, 11 years 0.17, 95% CI 0.04-0.31] and with the presence of overweight [odds ratio (OR) 3 years 1.19, 95% CI 1.03-1.37, 5 years OR 1.20, 95% CI 1.03-1.40, 11 years OR 1.21, 95% CI 1.02-1.45], adjusted for sex, SEP and birth weight z-score. Current informal care had the strongest association. However, informal child care at 5 years also contributed. There was no evidence of differences by sex or SEP.

CONCLUSIONS

In a developed, non-Western setting, informal child care was associated with childhood obesity. Modifiable attributes of informal child care warrant investigation for obesity prevention.