Exploring the impact of early life factors on inequalities in risk of overweight in UK children: findings from the UK Millennium Cohort Study

Obesity risk in young adults from the Jerusalem Perinatal Study (JPS): the contribution of polygenic risk and early life exposure

BACKGROUND/OBJECTIVES

The effects of early life exposures on offspring life-course health are well established. This study assessed whether adding early socio-demographic and perinatal variables to a model based on polygenic risk score (PRS) improves prediction of obesity risk.

METHODS

We used the Jerusalem Perinatal study (JPS) with data at birth and body mass index (BMI) and waist circumference (WC) measured at age 32. The PRS was constructed using over 2.1M common SNPs identified in genome-wide association study (GWAS) for BMI. Linear and logistic models were applied in a stepwise approach. We first examined the associations between genetic variables and obesity-related phenotypes (e.g., BMI and WC). Secondly, socio-demographic variables were added and finally perinatal exposures, such as maternal pre-pregnancy BMI (mppBMI) and gestational weight gain (GWG) were added to the model. Improvement in prediction of each step was assessed using measures of model discrimination (area under the curve, AUC), net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

RESULTS

One standard deviation (SD) change in PRS was associated with a significant increase in BMI (β = 1.40) and WC (β = 2.45). These associations were slightly attenuated (13.7-14.2%) with the addition of early life exposures to the model. Also, higher mppBMI was associated with increased offspring BMI (β = 0.39) and WC (β = 0.79) (p < 0.001). For obesity (BMI ≥ 30) prediction, the addition of early socio-demographic and perinatal exposures to the PRS model significantly increased AUC from 0.69 to 0.73. At an obesity risk threshold of 15%, the addition of early socio-demographic and perinatal exposures to the PRS model provided a significant improvement in reclassification of obesity (NRI, 0.147; 95% CI 0.068-0.225).

CONCLUSIONS

Inclusion of early life exposures, such as mppBMI and maternal smoking, to a model based on PRS improves obesity risk prediction in an Israeli population-sample.

Maternal obesity increases the risk of hepatocellular carcinoma through the transmission of an altered gut microbiome

Background & Aims

Emerging evidence suggests that maternal obesity negatively impacts the health of offspring. Additionally, obesity is a risk factor for hepatocellular carcinoma (HCC). Our study aims to investigate the impact of maternal obesity on the risk for HCC development in offspring and elucidate the underlying transmission mechanisms.

Methods

Female mice were fed either a high-fat diet (HFD) or a normal diet (ND). All offspring received a ND after weaning. We studied liver histology and tumor load in a N-diethylnitrosamine (DEN)-induced HCC mouse model.

Results

Maternal obesity induced a distinguishable shift in gut microbial composition. At 40 weeks, female offspring of HFD-fed mothers (HFD offspring) were more likely to develop steatosis (9.43% vs. 3.09%, p = 0.0023) and fibrosis (3.75% vs. 2.70%, p = 0.039), as well as exhibiting an increased number of inflammatory infiltrates (4.8 vs. 1.0, p = 0.018) and higher expression of genes involved in fibrosis and inflammation, compared to offspring of ND-fed mothers (ND offspring). A higher proportion of HFD offspring developed liver tumors after DEN induction (79.8% vs. 37.5%, p = 0.0084) with a higher mean tumor volume (234 vs. 3 μm3, p = 0.0041). HFD offspring had a significantly less diverse microbiota than ND offspring (Shannon index 2.56 vs. 2.92, p = 0.0089), which was rescued through co-housing. In the principal component analysis, the microbiota profile of co-housed animals clustered together, regardless of maternal diet. Co-housing of HFD offspring with ND offspring normalized their tumor load.

Conclusions

Maternal obesity increases female offspring's susceptibility to HCC. The transmission of an altered gut microbiome plays an important role in this predisposition.

Impact and implications

The worldwide incidence of obesity is constantly rising, with more and more children born to obese mothers. In this study, we investigate the impact of maternal diet on gut microbiome composition and its role in liver cancer development in offspring. We found that mice born to mothers with a high-fat diet inherited a less diverse gut microbiome, presented chronic liver injury and an increased risk of developing liver cancer. Co-housing offspring from normal diet- and high-fat diet-fed mothers restored the gut microbiome and, remarkably, normalized the risk of developing liver cancer. The implementation of microbial screening and restoration of microbial diversity holds promise in helping to identify and treat individuals at risk to prevent harm for future generations.

Optimal timing of introduction of complementary feeding: a systematic review and meta-analysis

CONTEXT

The timing of introducing complementary feeding (CF) is crucial because premature or delayed CF can be associated with adverse health outcomes in childhood and adulthood.

OBJECTIVE

This systematic review aims to evaluate the impact of the timing of CF introduction on health, nutrition, and developmental outcomes among normal-term infants.

DATA SOURCES

Electronic databases and trial registries were searched, along with the reference lists of the included studies and relevant systematic reviews.

DATA EXTRACTION

Two investigators independently extracted data from the included studies on a standardized data-extraction form.

DATA ANALYSIS

Data were meta-analyzed separately for randomized controlled trials (RCTs) and observational studies on the basis of early introduction of CF (< 3 months, < 4 months, < 6 months of age) or late introduction of CF (> 6 months, > 8 months of age). Evidence was summarized according to GRADE criteria. In total, 268 documents were included in the review, of which 7 were RCTs (from 24 articles) and 217 were observational studies (from 244 articles). Evidence from RCTs did not suggest an impact of early introduction, while low-certainty evidence from observational studies suggested that early introduction of CF (< 6 months) might increase body mass index (BMI) z score and overweight/obesity. Early introduction at < 3 months might increase BMI and odds of lower respiratory tract infection (LRTI), and early introduction at < 4 months might increase height, LRTI, and systolic and diastolic blood pressure (BP). For late introduction of CF, there was a lack of evidence from RCTs, but low-certainty evidence from observational studies suggests that late introduction of CF (> 6 months) might decrease height, BMI, and systolic and diastolic BP and might increase odds of intestinal helminth infection, while late introduction of CF (> 8 months) might increase height-for-age z score.

CONCLUSION

Insufficient evidence does suggest increased adiposity with early introduction of CF. Hence, the current recommendation of introduction of CF should stand, though more robust studies, especially from low- and middle-income settings, are needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42020218517.

Obesity Prediction in Young Adults from the Jerusalem Perinatal Study: Contribution of Polygenic Risk and Early Life Exposures

We assessed whether adding early life exposures to a model based on polygenic risk score (PRS) improves prediction of obesity risk. We used a birth cohort with data at birth and BMI and waist circumference (WC) measured at age 32. The PRS was composed of SNPs identified in GWAS for BMI. Linear and logistic models were used to explore associations with obesity-related phenotypes. Improvement in prediction was assessed using measures of model discrimination (AUC), and net reclassification improvement (NRI). One SD change in PRS was associated with a significant increase in BMI and WC. These associations were slightly attenuated (13.7%-14.2%) with the addition of early life exposures to the model. Also, higher maternal pre-pregnancy BMI was associated with increase in offspring BMI and WC (p<0.001). For prediction obesity (BMI ≥ 30), the addition of early life exposures to the PRS model significantly increase the AUC from 0.69 to 0.73. At an obesity risk threshold of 15%, the addition of early life exposures to the PRS model provided a significant improvement in reclassification of obesity (NRI, 0.147; 95% CI 0.068-0.225). We conclude that inclusion of early life exposures to a model based on PRS improves obesity risk prediction in an Israeli population-sample.

Impact of cuts to local authority spending on cultural, environmental and planning services on inequalities in childhood obesity in England: A longitudinal ecological study

BACKGROUND

Almost 20% of children in England are living with obesity by the end of primary school, with marked and growing inequalities driven by increasing prevalence in more deprived areas. Neighbourhood environments are upstream determinants of childhood weight status. Cultural, Environmental and Planning (CEP) services delivered by local authorities (LAs) in England include various services that contribute to these local environments, e.g. leisure centres, parks, playgrounds, libraries, community safety and environmental protection. Children in deprived areas potentially benefit most from the provision of these universal services. Spending on CEP services has been cut dramatically over the past decade, especially in more deprived areas. Given the potential link between these services and childhood obesity, we examined whether recent cuts in LA spending on CEP services are associated with trends and inequalities in obesity.

METHODS

We compiled annual data (2009-2017) on CEP spending in 324 LAs in England, from Ministry of Housing, Communities and Local Government reports. Obesity prevalence data for Year 6 children were obtained from the National Child Measurement Programme, for LAs and Middle-layer Super Output Areas (MSOAs). Following descriptive and pooled OLS analyses, we used fixed effects panel regression to estimate associations between CEP spending and obesity prevalence, within LAs over time, adjusting for potential confounding by local economic conditions and spending on other public services. Final models included an interaction term between area deprivation (2015 IMD) and year to account for differential background trends in obesity across deprivation levels. We tested for effect modification by deprivation and, using MSOA-level obesity data, explored associations between spending and within-LA obesity inequalities.

RESULTS

In unadjusted pooled OLS analyses, areas with higher CEP spending had higher prevalence of obesity, reflecting the strong social gradient in childhood obesity and the higher levels of central government funding allocated to more deprived areas. Deprivation, other spend, and local economic conditions explained this relationship. In the fixed effects analysis, designed to isolate average within-area change in obesity associated with changing spend, we observed a 0.10 percentage point increase in obesity prevalence for each 10% reduction in spend (95%CI: 0.04,0.15; p < 0.001), but this disappeared after accounting for differential background trends in obesity across deprivation levels (-0.02; 95%CI: 0.07,0.03; p = 0.39). Similar results were observed for obesity inequalities, although sensitivity analyses suggest spending on Environmental Services in particular may affect inequalities in urban local authorities.

CONCLUSIONS

CEP spending levels may influence local childhood obesity risk, but the increasing prevalence and widening inequalities in obesity of the past decade seem to have been driven mainly by factors other than CEP spending cuts, that are also unevenly distributed across deprivation levels. The influence of specific services might be obscured by grouping CEP services for analysis.

Socio-economic and ethnic disparities in childhood cancer survival, Yorkshire, UK

BACKGROUND

Establishing the existence of health inequalities remains a high research and policy agenda item in the United Kingdom. We describe ethnic and socio-economic differences in paediatric cancer survival, focusing specifically on the extent to which disparities have changed over a 20-year period.

METHODS

Cancer registration data for 2674 children (0-14 years) in Yorkshire were analysed. Five-year survival estimates by ethnic group (south Asian/non-south Asian) and Townsend deprivation fifths (I-V) were compared over time (1997-2016) for leukaemia, lymphoma, central nervous system (CNS) and other solid tumours. Hazard ratios (HR: 95% CI) from adjusted Cox models quantified the joint effect of ethnicity and deprivation on mortality risk over time, framed through causal interpretation of the deprivation coefficient.

RESULTS

Increasing deprivation was associated with significantly higher risk of death for children with leukaemia (1.11 (1.03-1.20)) and all cancers between 1997 and 2001. While we observed a trend towards reducing differences in survival over time in this group, a contrasting trend was observed for CNS tumours whereby sizeable variation in outcome remained for cases diagnosed until 2012. South Asian children with lymphoma had a 15% reduced chance of surviving at least 5 years compared to non-south Asian, across the study period.

DISCUSSION

Even in the United Kingdom, with a universally accessible healthcare system, socio-economic and ethnic disparities in childhood cancer survival exist. Findings should inform where resources should be directed to provide all children with an equitable survival outcome following a cancer diagnosis.

A. Sørensen T, Elhakeem A, Santos AC, Pinot de Moira A, Heude B, Iñiguez C, Pizzi C, Simons E, Voerman E, Corpeleijn E, Zariouh F, Santorelli G, Inskip HM, Barros H, Carson J, Harris JR, Nader JL, Ronkainen J, Strandberg-Larsen K, Santa-Marina L, Calas L, Cederkvist L, Popovic M, Charles MA, Welten M, Vrijheid M, Azad M, Subbarao P, Burton P, Mandhane PJ, Huang RC, Wilson RC, Haakma S, Fernández-Barrés S, Turvey S, Santos S, Tough SC, Sebert S, Moraes TJ, Salika T, Jaddoe VWV, Lawlor DA, Nybo Andersen AM. Gestational age at birth and body size from infancy through adolescence: An individual participant data meta-analysis on 253,810 singletons in 16 birth cohort studies

BACKGROUND

Preterm birth is the leading cause of perinatal morbidity and mortality and is associated with adverse developmental and long-term health outcomes, including several cardiometabolic risk factors and outcomes. However, evidence about the association of preterm birth with later body size derives mainly from studies using birth weight as a proxy of prematurity rather than an actual length of gestation. We investigated the association of gestational age (GA) at birth with body size from infancy through adolescence.

METHODS AND FINDINGS

We conducted a two-stage individual participant data (IPD) meta-analysis using data from 253,810 mother-child dyads from 16 general population-based cohort studies in Europe (Denmark, Finland, France, Italy, Norway, Portugal, Spain, the Netherlands, United Kingdom), North America (Canada), and Australasia (Australia) to estimate the association of GA with body mass index (BMI) and overweight (including obesity) adjusted for the following maternal characteristics as potential confounders: education, height, prepregnancy BMI, ethnic background, parity, smoking during pregnancy, age at child's birth, gestational diabetes and hypertension, and preeclampsia. Pregnancy and birth cohort studies from the LifeCycle and the EUCAN-Connect projects were invited and were eligible for inclusion if they had information on GA and minimum one measurement of BMI between infancy and adolescence. Using a federated analytical tool (DataSHIELD), we fitted linear and logistic regression models in each cohort separately with a complete-case approach and combined the regression estimates and standard errors through random-effects study-level meta-analysis providing an overall effect estimate at early infancy (>0.0 to 0.5 years), late infancy (>0.5 to 2.0 years), early childhood (>2.0 to 5.0 years), mid-childhood (>5.0 to 9.0 years), late childhood (>9.0 to 14.0 years), and adolescence (>14.0 to 19.0 years). GA was positively associated with BMI in the first decade of life, with the greatest increase in mean BMI z-score during early infancy (0.02, 95% confidence interval (CI): 0.00; 0.05, p < 0.05) per week of increase in GA, while in adolescence, preterm individuals reached similar levels of BMI (0.00, 95% CI: -0.01; 0.01, p 0.9) as term counterparts. The association between GA and overweight revealed a similar pattern of association with an increase in odds ratio (OR) of overweight from late infancy through mid-childhood (OR 1.01 to 1.02) per week increase in GA. By adolescence, however, GA was slightly negatively associated with the risk of overweight (OR 0.98 [95% CI: 0.97; 1.00], p 0.1) per week of increase in GA. Although based on only four cohorts (n = 32,089) that reached the age of adolescence, data suggest that individuals born very preterm may be at increased odds of overweight (OR 1.46 [95% CI: 1.03; 2.08], p < 0.05) compared with term counterparts. Findings were consistent across cohorts and sensitivity analyses despite considerable heterogeneity in cohort characteristics. However, residual confounding may be a limitation in this study, while findings may be less generalisable to settings in low- and middle-income countries.

CONCLUSIONS

This study based on data from infancy through adolescence from 16 cohort studies found that GA may be important for body size in infancy, but the strength of association attenuates consistently with age. By adolescence, preterm individuals have on average a similar mean BMI to peers born at term.

Mediators of socioeconomic differences in overweight and obesity among youth in Ireland and the UK (2011–2021): a systematic review

Background

By 2025, adult obesity prevalence is projected to increase in 44 of 53 of European-region countries. Childhood obesity tracks directly onto adult obesity, and children of low socioeconomic position families are at disproportionately higher risk of being obese compared with their more affluent peers. A previous review of research from developed countries identified factors mediating this relationship. This systematic review updates and extends those findings specifically within the context of Ireland and the United Kingdom.

Objective

The aim of this systematic review is to summarise peer-reviewed research completed in Ireland and the United Kingdom between 2011–2021 examining mediators of socioeconomic differentials in adiposity outcomes for youth.

Design

An electronic search of four databases, Ovid MEDLINE, Embase, Web of Science and EBSCOhost was conducted. Quantitative studies, published in the English language, examining mediators of socioeconomic differentials in adiposity outcomes in youth, and conducted in Ireland and the United Kingdom between 2011–2021 were included. An appraisal of study quality was completed. The systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

Following screening, a total of 23 papers were eligible for inclusion. Results indicate socioeconomic differentials for Ireland and the United Kingdom follow similar patterns to other developed countries and have similar mediating factors including early life and parent-level factors. However, this review identified additional factors that mediate the relationship, namely access to green space and favorable neighborhood conditions. Identifying these factors present further opportunities for potential interventions and confirm the requirement for tailored and appropriate research and interventions for Ireland and the United Kingdom.

Conclusion

This review identified several modifiable factors that should be considered when planning interventions aimed at reducing socioeconomic differentials in adiposity among youth in Ireland and the United Kingdom. Support was found for interventions to be made as early as possible in an at-risk child’s life, with the prenatal and preschool periods considered the most efficacious. Results were equivocal about the role of physical activity in the risk of childhood overweight and obesity. While multi-country analyses provide excellent overviews, country- or area-specific research may produce more nuanced, and potentially more powerful findings, which can help better inform policy responses and interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14004-z.

Pre-school childcare and inequalities in child development

Centre-based childcare may benefit pre-school children and alleviate inequalities in early childhood development, but evidence on socio-emotional and physical health outcomes is limited. Data were from the UK Millennium Cohort Study (n = 14,376). Inverse-probability weighting was used to estimate confounder-adjusted population-average effects of centre and non-centre-based childcare (compared to parental care only) between ages 26-31 months on (age 3): internalising and externalising symptoms, pro-social behaviour, independence, emotional dysregulation, vocabulary, school readiness, and body mass index. To assess impacts on inequalities, controlled direct effects of low parental education and lone parenthood on all outcomes were estimated under two hypothetical scenarios: 1) universal take-up of centre-based childcare; and 2) parental care only. On average, non-centre based childcare improved vocabulary and centre-based care improved school readiness, with little evidence of other benefits. However, socio-economic inequalities were observed for all outcomes and were attenuated in scenario 1 (universal take-up). For example, inequalities in externalising symptoms (according to low parental education) were reduced from a confounder-adjusted standard deviation difference of 7.8 (95% confidence intervals: 6.7-8.8), to 1.7 (0.6-2.7). Inequalities by parental education in scenario 2 (parental care only) were wider than in scenario 1 for externalising symptoms (at 3.4; 2.4-4.4), and for emotional dysregulation and school readiness. Inequalities by lone parenthood, which were smaller, fell in scenario 1, and fell further in scenario 2. Universal access to centre-based pre-school care may alleviate inequalities, while restricted access (e.g. during lockdown for a pandemic such as Covid-19) may widen some inequalities in socioemotional and cognitive development.

How do early-life adverse childhood experiences mediate the relationship between childhood socioeconomic conditions and adolescent health outcomes in the UK?

Background

Both adverse childhood experiences (ACEs) and adverse childhood socioeconomic conditions (SECs) in early life are associated with poor outcomes across the life course. However, the complex interrelationships between childhood SECs and ACEs are unclear, as are the consequences for health outcomes beyond childhood. We therefore assessed the extent to which early-life ACEs mediate the relationship between SECs and socioemotional behavioural problems, cognitive disability and overweight/obesity in adolescence.

Methods

We used longitudinal data from the UK Millennium Cohort Study (MSC). Outcomes assessed at age 14 were socioemotional behavioural problems, cognitive disability and overweight/obesity. SECs at birth were measured by maternal education. Potentially mediating ACEs measured up to 5 years were verbal and physical maltreatment, parental drug use, domestic violence, parental divorce, maternal mental illness and high frequency of parental alcohol use. We used counterfactual mediation analysis to assess the extent to which ACEs mediate the association between SECs at birth and behavioural, cognitive and physical outcomes at age 14, estimating total (TE), natural direct and indirect effects, and mediated proportions.

Results

Children with disadvantaged SECs were more likely to have socioemotional behavioural problems (relative risk (RR) 3.85, 95% CI 2.48 to 5.97), cognitive disability (RR 3.87, 95% CI 2.33 to 6.43) and overweight/obesity (RR 1.61, 95% CI 1.32 to 1.95), compared to those with more advantaged SECs. Overall, 18% of the TE of SECs on socioemotional behavioural problems was mediated through all ACEs investigated. For cognitive disability and overweight/obese, the proportions mediated were 13% and 19%, respectively.

Conclusion

ACEs measured up to age 5 years in the MCS explained about one-sixth of inequalities in adolescents behavioural, cognitive and physical outcomes.

Perinatal exposure to maternal obesity: Lasting cardiometabolic impact on offspring

Evidence from epidemiological, clinical, and animal model studies clearly demonstrates that prenatal and lactational maternal obesity and high-fat diet consumption are associated with cardiometabolic morbidity in offspring. Fetal and offspring sex may be an important effect modifier. Adverse offspring cardiometabolic outcomes observed in the setting of maternal obesity include an increased risk for obesity, features of metabolic syndrome (hypertension, hyperglycemia and insulin resistance, hyperlipidemia, increased adiposity), and non-alcoholic fatty liver disease. This review article synthesizes human and animal data linking maternal obesity and high-fat diet consumption in pregnancy and lactation to adverse cardiometabolic outcomes in offspring. We review key mechanisms underlying skeletal muscle, adipose tissue, pancreatic, liver, and central brain reward programming in obesity-exposed offspring, and how such malprogramming contributes to offspring cardiometabolic morbidity.

Time-varying Effects of Screen Media Exposure in the Relationship Between Socioeconomic Background and Childhood Obesity

BACKGROUND

We investigated to what extent social inequalities in childhood obesity could be reduced by eliminating differences in screen media exposure.

METHODS

We used longitudinal data from the UK-wide Millennium Cohort Study (n = 11,413). The study measured mother's educational level at child's age 5. We calculated screen media exposure as a combination of television viewing and computer use at ages 7 and 11. We derived obesity at age 14 from anthropometric measures. We estimated a counterfactual disparity measure of the unmediated association between mother's education and obesity by fitting an inverse probability-weighted marginal structural model, adjusting for mediator-outcome confounders.

RESULTS

Compared with children of mothers with a university degree, children of mothers with education to age 16 were 1.9 (95% confidence interval [CI] = 1.5, 2.3) times as likely to be obese. Those whose mothers had no qualifications were 2.0 (95% CI = 1.5, 2.5) times as likely to be obese. Compared with mothers with university qualifications, the estimated counterfactual disparity in obesity at age 14, if educational differences in screen media exposure at age 7 and 11 were eliminated, was 1.8 (95% CI = 1.4, 2.2) for mothers with education to age 16 and 1.8 (95% CI = 1.4, 2.4) for mothers with no qualifications on the risk ratio scale. Hence, relative inequalities in childhood obesity would reduce by 13% (95% CI = 1%, 26%) and 17% (95% CI = 1%, 33%). Estimated reductions on the risk difference scale (absolute inequalities) were of similar magnitude.

CONCLUSIONS

Our findings are consistent with the hypothesis that social inequalities in screen media exposure contribute substantially to social inequalities in childhood obesity.

Predicting the risk of childhood overweight and obesity at 4-5 years using population-level pregnancy and early-life healthcare data

BACKGROUND

Nearly a third of children in the UK are overweight, with the prevalence in the most deprived areas more than twice that in the least deprived. The aim was to develop a risk identification model for childhood overweight/obesity applied during pregnancy and early life using routinely collected population-level healthcare data.

METHODS

A population-based anonymised linked cohort of maternal antenatal records (January 2003 to September 2013) and birth/early-life data for their children with linked body mass index (BMI) measurements at 4-5 years (n = 29,060 children) in Hampshire, UK was used. Childhood age- and sex-adjusted BMI at 4-5 years, measured between September 2007 and November 2018, using a clinical cut-off of ≥ 91st centile for overweight/obesity. Logistic regression models together with multivariable fractional polynomials were used to select model predictors and to identify transformations of continuous predictors that best predict the outcome.

RESULTS

Fifteen percent of children had a BMI ≥ 91st centile. Models were developed in stages, incorporating data collected at first antenatal booking appointment, later pregnancy/birth, and early-life predictors (1 and 2 years). The area under the curve (AUC) was lowest (0.64) for the model only incorporating maternal predictors from early pregnancy and highest for the model incorporating all factors up to weight at 2 years for predicting outcome at 4-5 years (0.83). The models were well calibrated. The prediction models identify 21% (at booking) to 24% (at ~ 2 years) of children as being at high risk of overweight or obese by the age of 4-5 years (as defined by a ≥ 20% risk score). Early pregnancy predictors included maternal BMI, smoking status, maternal age, and ethnicity. Early-life predictors included birthweight, baby's sex, and weight at 1 or 2 years of age.

CONCLUSIONS

Although predictive ability was lower for the early pregnancy models, maternal predictors remained consistent across the models; thus, high-risk groups could be identified at an early stage with more precise estimation as the child grows. A tool based on these models can be used to quantify clustering of risk for childhood obesity as early as the first trimester of pregnancy, and can strengthen the long-term preventive element of antenatal and early years care.

Family Income Gradients in Adolescent Obesity, Overweight and Adiposity Persist in Extremely Deprived and Extremely Affluent Neighbourhoods but Not in Middle-Class Neighbourhoods: Evidence from the UK Millennium Cohort Study

We investigated whether family income gradients in obesity, overweight, and adiposity persist at geographic-level deprivation quintiles using a nationally representative cohort of UK adolescents. Data from 11,714 eligible adolescents from the sixth sweep of the Millennium Cohort Study (14 years old) were analysed in this study. The International Obesity Task Force age- and sex-specific thresholds were used to define obesity and overweight. Self-reported family income was standardized using the Organisation for Economic Co-operation and Development (OECD)'s equivalised income scale. Geographic-level deprivation was defined by the index of multiple deprivation 2004. Results showed that the prevalence of obesity and overweight was 8.0% and 27.2%, respectively. Mean percentage body fat was 16.9% (standard error, SE = 0.2%) in male and 27.3% (SE = 0.1%) in female adolescents. Risk of obesity, overweight, and adiposity increased with decreasing family income quintiles (p for trend <0.001). After stratifying by geographic-level deprivation quintiles, a U-shaped association emerged, whereby family income gradients in the risk of adolescent obesity and adiposity persisted in extremely affluent and extremely deprived neighbourhoods but attenuated to non-significance in middle-class neighbourhoods. These results focus on the findings from England. Recognition of the persistence of inequalities in the risk of obesity in the most deprived and affluent neighbourhoods may be necessary in planning public health resources and interventions.

Influence of early-life risk factors on socioeconomic inequalities in weight gain

Background

Previous research has examined the role of early-life risk factors on childhood weight gain.The extent to which these factors drive socioeconomic differences in weight is unclear. We aimed to quantify the influence of early-life risk factors on the development of socioeconomic inequalities in children's body mass index (BMI) z-score at 10-11 years.

Methods

Overall, 2186 children from the Longitudinal Study of Australian Children were examined. Socioeconomic position (SEP) was measured as a continuous composite of parent's education, occupation and income. The Product of Coefficients mediation method was used to quantify the contribution of maternal smoking during pregnancy, gestational diabetes, prematurity, caesarean section, birthweight, not being breastfed, early introduction of solid food, maternal BMI and paternal BMI to the relationship between SEP and BMI z-score.

Results

Each increasing decile of SEP (higher SEP) was associated with a 0.05 unit lower (95% CI: -0.06, -0.03) BMI z-score at 10-11 years. In total, 83.5% of these differences in BMI z-score could be explained by socioeconomic differences in maternal smoking during pregnancy (26.9%), maternal BMI (39.6%) and paternal BMI (17.0%).

Conclusions

Interventions to reduce socioeconomic inequalities in excess weight gain during childhood should support the attainment of a healthy parental weight and prevent smoking during pregnancy.

How do early-life factors explain social inequalities in adolescent mental health? Findings from the UK Millennium Cohort Study

BACKGROUND

Reducing inequalities in adolescent mental health is a public health priority, yet the pathways that link social conditions to mental health outcomes in the early years are unclear. We aimed to evaluate the extent to which early years risk factors explain social inequalities in adolescent mental health in the UK.

METHODS

We analysed data from 6509 children captured in the UK Millennium Cohort Study. Mental health was assessed through the socioemotional behavioural problems at age 14 (Strengths and Difficulties Questionnaire). The main exposure was maternal education at birth, used as a measure of childhood socioeconomic conditions (SECs), and used to calculate the relative index of inequality. Using causal mediation analysis, we assessed how perinatal, individual child, family, peer relation and neighbourhood-level factors measured up to age 3-mediated the total effect (TE) of SECs on adolescent socioemotional behavioural problems, estimating the proportion mediated and natural indirect effect (NIE) via each block of mediators, and all mediators together.

RESULTS

Children of mothers with no qualification were almost four times as likely to have socioemotional behavioural problems compared with degree plus level (relative risk (RR) 3.82, 95% CI 2.48 to 5.88). Overall, 63.9% (95% CI 50.2% to 77.6%) (NIE RR 1.97, 95% CI 1.63 to 2.37) of the TE (RR 4.40, 95% CI 3.18 to 6.07) of social inequalities on risk of adolescent socioemotional behavioural problems was mediated by early-life factors.

CONCLUSIONS

About two-thirds of the social inequality in adolescent mental health was explained by early risk factors measured by age 3, highlighting the importance of public health interventions in this period.

Appropriate age range for introduction of complementary feeding into an infant's diet

Following a request from the European Commission, the Panel on Nutrition, Novel Foods and Food Allergens (NDA) revised its 2009 Opinion on the appropriate age for introduction of complementary feeding of infants. This age has been evaluated considering the effects on health outcomes, nutritional aspects and infant development, and depends on the individual's characteristics and development. As long as foods have an age-appropriate texture, are nutritionally appropriate and prepared following good hygiene practices, there is no convincing evidence that at any age investigated in the included studies (< 1 to < 6 months), the introduction of complementary foods (CFs) is associated with adverse health effects or benefits (except for infants at risk of iron depletion). For nutritional reasons, the majority of infants need CFs from around 6 months of age. Infants at risk of iron depletion (exclusively breastfed infants born to mothers with low iron status, or with early umbilical cord clamping (< 1 min after birth), or born preterm, or born small-for-gestational age or with high growth velocity) may benefit from earlier introduction of CFs that are a source of iron. The earliest developmental skills relevant for consuming pureed CFs can be observed between 3 and 4 months of age. Skills for consuming finger foods can be observed in some infants at 4 months, but more commonly at 5-7 months. The fact that an infant may be ready from a neurodevelopmental perspective to progress to a more diversified diet before 6 months of age does not imply that there is a need to introduce CFs. There is no reason to postpone the introduction of potentially allergenic foods (egg, cereals, fish and peanut) to a later age than that of other CFs as far as the risk of developing atopic diseases is concerned. Regarding the risk of coeliac disease, gluten can be introduced with other CFs.

Microsimulation model of child and adolescent overweight: making use of what we already know

BACKGROUND

New Zealand has high rates of child overweight and obesity when compared with other countries. Despite an abundance of research documenting the problem, it is unclear what the most effective policy changes or interventions are, and how policy changes might unfold over time within complex systems.

METHODS

We use estimates derived from meta-analyses to create a dynamic microsimulation model of child overweight (including obesity). Using census records we created a synthetic birth cohort of 10,000 children. Information on parental education, ethnicity and father's socio-economic position at birth were taken from census records. We used the New Zealand Health Survey to estimate population base rates for the prevalence of overweight and obesity. Information on other modifiers (such as maternal smoking, breastfeeding, preterm birth, regular breakfast consumption and so forth) were taken from three birth cohorts: Christchurch Health and Development Study, The Dunedin Multidisciplinary Health and Development Study and the Pacific Islands Families Study. Published intervention studies were used to derive plausible estimates for changes to modifiers.

RESULTS

Reducing the proportion of mothers classified as overweight and obesity (-3.31(95% CI -3.55; -3.07) percentage points), reducing the proportion of children watching two or more hours of TV (-3.78(95% CI -4.01; -3.54)), increasing the proportion of children eating breakfast regularly (-1.71(95% CI -1.96; -1.46)), and reducing the proportion of children born with high birth weights (-1.36(95% CI -1.61; -1.11)), lead to sizable decreases in the estimated prevalence of child overweight (including obesity). Reducing the proportion of mothers giving birth by caesarean (-0.23(95% CI -0.49; -0.23)) and increasing parental education (-0.07(95% CI -0.31; 0.18)) did not impact upon child overweight rates.

CONCLUSIONS

We created a working simulation model of New Zealand children that can be accessed by policy makers and researchers to determine known relationships between predictors and child overweight, as well as potential gains from targeting specific pathways.

When richer doesn't mean thinner: Ethnicity, socioeconomic position, and the risk of child obesity in the United Kingdom

BACKGROUND

A range of studies report a robust association between family socioeconomic position and the prevalence of child overweight/obesity. On average, children from poorer backgrounds are more likely to be overweight/obese than children from more advantaged families. However, a small number of US studies have shown that, for ethnic minority children, the association is either nonexistent or reversed.

OBJECTIVE

We test if the link between socioeconomic position and child overweight/obesity at age 7 is heterogeneous in the United Kingdom where rates of obesity are particularly high for some groups of ethnic minority children.

METHODS

We use nationally representative data from the UK Millennium Cohort Study as well as descriptive analyses and logistic regression models.

RESULTS

Poorer White children are at higher risk of overweight/obesity than higher income White children. However, socioeconomic disparities are reversed for Black African/Caribbean children and nonexistent for children of Indian and Pakistani/Bangladeshi origin. Moreover, the health behaviours that explain socioeconomic disparities in child overweight/obesity for the White group appear to be irrelevant in explaining differences by socioeconomic position for the Black Caribbean and African groups.

CONCLUSIONS

We should be careful in assuming that higher socioeconomic position is protective against child overweight/obesity for all groups of the population.

CONTRIBUTION

This study shows for the first time important variation by ethnicity in the link between socioeconomic position and child overweight/obesity - and in the underlying mechanisms linking them - in the United Kingdom.

The association between maternal body mass index and child obesity: A systematic review and meta-analysis

BACKGROUND

There is a global obesity crisis, particularly among women and disadvantaged populations. Early-life intervention to prevent childhood obesity is a priority for public health, global health, and clinical practice. Understanding the association between childhood obesity and maternal pre-pregnancy weight status would inform policy and practice by allowing one to estimate the potential for offspring health gain through channelling resources into intervention. This systematic review and meta-analysis aimed to examine the dose-response association between maternal body mass index (BMI) and childhood obesity in the offspring.

METHODS AND FINDINGS

Searches in MEDLINE, Child Development & Adolescent Studies, CINAHL, Embase, and PsycInfo were carried out in August 2017 and updated in March 2019. Supplementary searches included hand-searching reference lists, performing citation searching, and contacting authors. Two researchers carried out independent screening, data extraction, and quality assessment. Observational studies published in English and reporting associations between continuous and/or categorical maternal and child BMI or z-score were included. Categorical outcomes were child obesity (≥95th percentile, primary outcome), overweight/obesity (≥85th percentile), and overweight (85th to 95th percentile). Linear and nonlinear dose-response meta-analyses were conducted using random effects models. Studies that could not be included in meta-analyses were summarised narratively. Seventy-nine of 41,301 studies identified met the inclusion criteria (n = 59 cohorts). Meta-analyses of child obesity included 20 studies (n = 88,872); child overweight/obesity, 22 studies (n = 181,800); and overweight, 10 studies (n = 53,238). Associations were nonlinear and there were significantly increased odds of child obesity with maternal obesity (odds ratio [OR] 3.64, 95% CI 2.68-4.95) and maternal overweight (OR 1.89, 95% CI 1.62-2.19). Significantly increased odds were observed for child overweight/obesity (OR 2.69, 95% CI 2.10-3.46) and for child overweight (OR 1.80, 95% CI 1.25, 2.59) with maternal obesity. A limitation of this research is that the included studies did not always report the data in a format that enabled inclusion in this complex meta-analysis.

CONCLUSIONS

This research has identified a 264% increase in the odds of child obesity when mothers have obesity before conception. This study provides substantial evidence for the need to develop interventions that commence prior to conception, to support women of childbearing age with weight management in order to halt intergenerational obesity.

Relationship between socioeconomic status and weight gain during infancy: The BeeBOFT study

BACKGROUND

Increased weight gain during infancy is a risk factor for obesity and related diseases in later life. The aim of the present study was to investigate the association between socioeconomic status (SES) and weight gain during infancy, and to identify the factors mediating the association between SES and infant weight gain.

METHODS

Subjects were 2513 parent-child dyads participating in a cluster randomized controlled intervention study. Family SES was indexed by maternal education level. Weight gain in different time windows (infant age 0-3, 0-6, and 6-12 months) was calculated by subtracting the weight for age z-score (WAZ) between the two time-points. Path analysis was performed to examine the mediating pathways linking SES and infant weight gain.

RESULTS

On average, infants of low-educated mothers had a lower birth weight and caught-up at approximately 6 months. In the period of 0-6 months, infants with low-educated mothers had an 0.42 (95% CI 0.27-0.57) higher gain in weight for age z-score compared to children with high-educated mothers. The association between maternal education level and increased infant weight gain in the period of 0-6 months can be explained by infant birth weight, gestational age at child birth, duration of breastfeeding, and age at introduction of complementary foods. After adjusting all the mediating factors, there was no association between maternal education level and infant weight gain.

CONCLUSION

Infants with lower SES had an increased weight gain during the first 6 months of infancy, and the effect can be explained by infant birth weight, gestational age at child birth, and infant feeding practices.

Perinatal and lifestyle factors mediate the association between maternal education and preschool children's weight status: the ToyBox study

OBJECTIVE

This study aimed to explore the associations among perinatal, sociodemographic, and behavioral factors and preschool overweight/obesity.

METHODS

Data were collected from 7541 European preschoolers in May/June 2012. Children's anthropometrics were measured, and parents self-reported all other data via questionnaires. Level of statistical significance was set at P ≤ 0.05.

RESULTS

Certain perinatal factors (i.e., maternal prepregnancy overweight/obesity, maternal excess gestational weight gain, excess birth weight, and "rapid growth velocity"), children's energy balance-related behaviors (i.e., high sugar-sweetened beverage consumption, increased screen time, reduced active-play time), family sociodemographic characteristics (i.e., Eastern or Southern Europe, low maternal and paternal education), and parental overweight/obesity were identified as correlates of preschoolers' overweight/obesity. Furthermore, maternal prepregnancy overweight/obesity, children's "rapid growth velocity," and increased screen time mediated by 21.2%, 12.5%, and 5.7%, respectively, the association between maternal education and preschoolers' body mass index.

CONCLUSION

This study highlighted positive associations of preschooler's overweight/obesity with excess maternal prepregnancy and gestational weight gain, excess birth weight and "rapid growth velocity," Southern or Eastern European region, and parental overweight/obesity. Moreover, maternal prepregnancy overweight/obesity, children's "rapid growth velocity," and increased screen time partially mediated the association between maternal education and preschoolers' body mass index. The findings of the present study may support childhood obesity prevention initiatives, because vulnerable population groups and most specifically low-educated families should be prioritized. Among other fields, these intervention initiatives should also focus on the importance of normal prepregnancy maternal weight status, normal growth velocity during infancy, and retaining preschool children's screen time within recommendations.

Patterns of childhood body mass index (BMI), overweight and obesity in South Asian and black participants in the English National child measurement programme: effect of applying BMI adjustments standardising for ethnic differences in BMI-body fatness associations

Background:

The National Child Measurement Programme (NCMP) records weight and height and assesses overweight-obesity patterns in English children using body mass index (BMI), which tends to underestimate body fatness in South Asian children and overestimate body fatness in Black children of presumed African ethnicity. Using BMI adjustments to ensure that adjusted BMI was similarly related to body fatness in South Asian, Black and White children, we reassessed population overweight and obesity patterns in these ethnic groups in NCMP.

Methods:

Analyses were based on 2012–2013 NCMP data in 582 899 children aged 4–5 years and 485 362 children aged 10–11 years. Standard centile-based approaches defined weight status in each age group before and after applying BMI adjustments for English South Asian and Black children derived from previous studies using the deuterium dilution method.

Findings:

Among White children, overweight-obesity prevalences (boys, girls) were 23% and 21%, respectively, in 4–5 year olds and 33% and 30%, respectively, in 10–11 year olds. Before adjustment, South Asian children had lower overweight-obesity prevalences at 4–5 years (19%, 19%) and slightly higher prevalences at 10–11 years (42%, 34%), whereas Black children had higher overweight-obesity prevalences both at 4–5 years (31%, 29%) and 10–11 years (42%, 45%). Following adjustment, overweight-obesity prevalences were markedly higher in South Asian children both at 4–5 years (39%, 35%) and at 10–11 years (52%, 44%), whereas Black children had lower prevalences at 4–5 years (11%, 12%); at 10–11 years, prevalences were slightly lower in boys (32%) but higher in girls (35%).

Interpretation:

BMI adjustments revealed extremely high overweight-obesity prevalences among South Asian children in England, which were not apparent in unadjusted data. In contrast, after adjustment, Black children had lower overweight-obesity prevalences except among older girls.

Funding:

British Heart Foundation, NIHR CLAHRC (South London), NIHR CLAHRC (North Thames).

Explaining socioeconomic inequalities in exclusive breast feeding in Norway

BACKGROUND AND OBJECTIVE

In high-income countries, lower socioeconomic position is associated with lower rates of breast feeding, but it is unclear what factors explain this inequality. Our objective was to examine the association between socioeconomic position and exclusive breast feeding, and to explore whether socioeconomic inequality in exclusive breast feeding could be explained by other sociodemographic characteristics, for example, maternal age and parity, smoking habits, birth characteristics, quality of counselling and breastfeeding difficulties.

METHODS

We used data from a questionnaire sent to mothers when their infants were five completed months as part of a trial of a breastfeeding intervention in Norway. We used maternal education as an indicator of socioeconomic position. Analyses of 1598 mother-infant pairs were conducted using logistic regression to assess explanatory factors of educational inequalities in breast feeding.

RESULTS

Socioeconomic inequalities in exclusive breast feeding were present from the beginning and persisted for five completed months, when 22% of the most educated mothers exclusively breast fed compared with 7% of the least educated mothers: OR 3.39 (95% CI 1.74 to 6.61). After adjustment for all potentially explanatory factors, the OR was reduced to 1.49 (95% CI 0.70 to 3.14). This decrease in educational inequality seemed to be mainly driven by sociodemographic factors, smoking habits and breastfeeding difficulties, in particular perceived milk insufficiency.

CONCLUSIONS

Socioeconomic inequalities in exclusive breast feeding at 5 months were largely explained by sociodemographic factors, but also by modifiable factors, such as smoking habits and breastfeeding difficulties, which can be amenable to public health interventions.

TRIAL REGISTRATION NUMBER

NCT01025362.

A scoping review of epidemiologic risk factors for pediatric obesity: Implications for future childhood obesity and dental caries prevention research

RESEARCH QUESTIONS

What are the non-modifiable (socioeconomic, genetic) and modifiable factors (physical activity, dietary behaviors) related to childhood (under age 12) obesity? How can this knowledge be applied to oral health professionals' efforts to prevent or manage dental caries in children?

OBJECTIVES

Studies have identified risk factors for childhood obesity. The purpose of this scoping review was to develop a conceptual model to identify non-modifiable and modifiable risk factors for childhood obesity and to illustrate how these findings are relevant in developing interventions aimed at preventing obesity and dental caries in children.

METHODS

The authors searched PubMed and Embase and limited the study to English-language publications. A total of 2,572 studies were identified. After de-duplication, 2,479 studies remained and were downloaded into a citation-management tool. Two authors screened the titles and abstracts for relevance. Two hundred and sixty studies remained and were retrieved for a full-text review, and 80 studies were excluded, resulting in 180 studies included in the scoping review. An inductive content analytic methods was used to organize all statistically significant obesity risk factors into seven domains, which were classified as non-modifiable or modifiable; then a conceptual model of common risk factors associated with childhood obesity and dental caries was developed.

RESULTS

Non-modifiable obesity risk factors include biological and developmental (e.g., genes, developmental conditions, puberty), sociodemographic and household (e.g., race/ethnicity, socioeconomic status, parent education, unemployment), cultural (e.g., degree of acculturation), and community (e.g., neighborhood composition). Modifiable risk factors included behavioral (e.g., diet, physical activity, weight), psychosocial (e.g., maternal stress, family functioning, parenting practices, child temperament), and medical (e.g., parent smoking, maternal health, child health).

CONCLUSIONS

Identifying common risk factors has important implications for future oral health research aimed at preventing childhood obesity and dental caries. Epidemiologic knowledge gleaned from the literature can be used to develop rigorous interventions and programs aimed at preventing these highly prevalent diseases and improving health outcomes for children.

Are social inequalities in early childhood smoking initiation explained by exposure to adult smoking? Findings from the UK Millennium Cohort Study

Introduction

To assess the socio-economic gradient in early smoking initiation at age 11 years and the extent to which any inequality was explained after accounting for longitudinal exposure to adult smoking.

Methods

Analysis of the UK Millennium Cohort Study, based on 9, 609 children from ages 9 months to 11 years. The outcome was smoking initiation by age 11. Odds ratios (ORs) for smoking initiation were estimated using logistic regression, according to maternal education, whilst adjusting for baseline demographic factors. Longitudinal exposure to a regular smoker in the same room was assessed as potential mediator of the association between maternal education and early smoking, along with other socially patterned risk factors for early smoking initiation, such as parental separation and mental health.

Results

Overall 2.7% (95% CI: 2.3–3.1) of children had tried a cigarette by age eleven. Children of mothers with no qualifications were more than six times as likely to have tried a cigarette than children of mothers with degree level qualifications or higher (OR 6.0 [95%CI 3.5–10.1]), with clear social gradient. Controlling for potentially mediating variables, particularly exposure to a regular adult smoker reduced the OR smoking initiation in children of mothers with no qualifications by 63% (aOR 2.9 [95%CI 1.7 to 5.1]).

Conclusions

Smoking initiation is more common in disadvantaged children, and this is largely explained by regular exposure to an adult smoker in the same room. Reducing adult smoking in front of children may reduce inequalities in smoking initiation in children by over a half.

A Review of the Field on Children's Exposure to Environmental Contaminants: A Risk Assessment Approach

Background: Children must be recognized as a sensitive population based on having biological systems and organs in various stages of development. The processes of absorption, distribution, metabolism and elimination of environmental contaminants within a child's body are considered less advanced than those of adults, making them more susceptible to disease outcomes following even small doses. Children's unique activities of crawling and practicing increased hand-to-mouth ingestion also make them vulnerable to greater exposures by certain contaminants within specific environments. Approach: There is a need to review the field of children's environmental exposures in order to understand trends and identify gaps in research, which may lead to better protection of this vulnerable and sensitive population. Therefore, explored here are previously published contemporary works in the broad area of children's environmental exposures and potential impact on health from around the world. A discussion of children's exposure to environmental contaminants is best organized under the last four steps of a risk assessment approach: hazard identification, dose-response assessment, exposure assessment (including children's activity patterns) and risk characterization. We first consider the many exposure hazards that exist in the indoor and outdoor environments, and emerging contaminants of concern that may help guide the risk assessment process in identifying focus areas for children. A section on special diseases of concern is also included. Conclusions: The field of children's exposures to environmental contaminants is broad. Although there are some well-studied areas offering much insight into children exposures, research is still needed to further our understanding of exposures to newer compounds, growing disease trends and the role of gene-environment interactions that modify adverse health outcomes. It is clear that behaviors of adults and children play a role in reducing or increasing a child's exposure, where strategies to better communicate and implement risk modifying behaviors are needed, and can be more effective than implementing   changes in the physical environment.

Effect of socioeconomic conditions on frequent complaints of pain in children: findings from the UK Millennium Cohort Study

BACKGROUND

Frequent complaints of pain (FCP) are common in high-income countries, affecting about 25% of children, and may have significant adverse consequences including prolonged school absence and disability. Most FCP are unexplained, and the aetiology is poorly understood. This study aimed to identify risk factors for FCP and explore how risk factors explain variation in pain reporting by childhood socioeconomic conditions (SECs).

METHODS

Analysis of the UK Millennium Cohort Study, including 8463 singleton children whose parents provided data throughout the study. At 11 years, mothers were asked whether their child frequently complains of pain. Risk ratios (RR) and 95% CIs for FCP were estimated using Poisson regression, according to maternal education. Other risk factors were explored to assess if they attenuated any association between FCP and SECs.

RESULTS

32.3% of children frequently complained of pain. Children of mothers with no educational qualifications were more likely to have FCP than children of mothers with higher degrees (RR 2.06, 95% CI 1.64 to 2.59) and there was a clear gradient across the socioeconomic spectrum. Female sex, fruit consumption, childhood mental health and maternal health measures were associated with childhood FCP in univariable and multivariable analyses. Inclusion of these factors within the model attenuated the RR by 17% to 1.70 (95% CI 1.36 to 2.13).

CONCLUSION

In this representative UK cohort, there was a significant excess of FCP reported in less advantaged children that was partially attenuated when accounting for indicators of parental and childhood mental health. Addressing these factors may partially reduce inequalities in childhood FCP.

Smoking in pregnancy: a cross-sectional study in China

BACKGROUND

Findings on smoking among pregnant women were mostly from high income countries and were rarely from China. This study aimed to estimate the prevalence of smoking and its influencing factors among pregnant women living in China.

METHODS

A cross-sectional analysis was conducted in this study. Data from pregnant women were collected in this study from June to August 2015 from 5 provinces of mainland China. A total of 2345 pregnant women were included in this study, the mean age of the participants was 28.12 years (SD 4.13).

RESULTS

About 82.9% of smoking women quit smoking after they were pregnant. The prevalence of smoking among pregnant women was 3.8%. Among the participants, 40.0, 30.7, 1.8, 29.9, 0.8, 31.4, 31.2, and 26.7% had husbands, fathers-in-law, mothers-in-law, fathers, mothers, colleagues, friends, and relatives, respectively, who were smokers. Compared with pregnant women of basic education level (junior middle school or below), those of the higher education level (undergraduate or above) were at higher risk of smoking (OR, 5.17; 95% CI, 2.00-13.39). Compared with pregnant women from rural areas, urban pregnant women were less likely to be current smokers (OR, 0.55; 95% CI, 0.32-0.94). Compared with pregnant women whose mothers-in-law did not smoke, those whose mothers-in-law smoked were at higher risk of smoking (OR, 4.67; 95% CI, 1.87-11.70). However, compared with pregnant women whose husband did not smoke, those whose husband smoked were not significantly at higher risk of smoking (OR, 1.12; 95% CI, 0.73-1.73).

CONCLUSIONS

Most of smoking women quit smoking after they became pregnant. Tailored intervention programs to reduce smoking in pregnant women should focus on those with higher education level, from rural areas, and pregnant women whose mothers-in-law smoke.