Distinct patterns of socio‐economic disparities in child‐to‐adolescent BMI trajectories across UK ethnic groups: A prospective longitudinal study

Abstract

Summary Background In many high‐income countries, body mass index (BMI)/obesity levels are inversely associated with socio‐economic position (SEP). Little is known whether socio‐economic patterns in BMI trajectories throughout childhood differ by ethnicity, especially in the United Kingdom. Objectives To investigate socio‐economic disparities in child‐to‐adolescent BMI trajectories and risks of overweight and obesity during adolescence across ethnic groups. Methods Mixed‐effects fractional polynomial and multinomial regression models were applied to estimate socio‐economic differences in BMI trajectories (3‐14 years) and risk of overweight/obesity at 14 years, respectively, in the UK Millennium Cohort Study (n = 15 996). Analysis was stratified by ethnicity. Result Poverty was associated with higher BMI in children of White and South Asian origins, with a small difference at 3 years, which widened with age to 0.75 kg/m2 (95% CI, 0.59‐0.91) and 0.77 kg/m2 (0.26‐1.27) at 14 years for the White and South Asian groups, respectively. There was a reverse income‐BMI association in children of Black (African‐Caribbean) origin with the poverty group having a lower BMI (−0.37 kg/m2 [−0.71 to ‐0.04] at 5 years; −0.95 kg/m2 [−1.79 to −0.11] at 14 years). These patterns also presented with maternal education as a SEP indicator and for obesity at 14 years. Conclusions Socio‐economic advantage may not be universally associated with lower BMI, which should be considered when planning obesity interventions. The positive SEP‐BMI association in children of Black origin requires replication and merits further investigation into underpinning mechanisms.

Socioeconomic inequalities and severe obesity—Sex differences in a nationwide study of 1.12 million Israeli adolescents

“…The impact of SEP on overweight and obesity during childhood is complex and a bivariate association between SEP and obesity has been described across populations 1,2 . In developed countries, the majority of studies show an inverse association between SEP and obesity 3,4 ; whereas in developing countries the association is reversed, with a positive association between more advantaged SEP and obesity 5,6 . Suggested explanations for the increased prevalence of obesity in families of less advantaged SEP include unhealthy infant feeding practices, 7 a greater consumption of less expensive, but calorie‐dense foods, 8 less physical activity, 9 short sleep duration, 10 and limited knowledge regarding healthy lifestyle 11,12 …”

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

“…Age 9 months: objectively measured wgt converted to z scores. Age 3: objectively measured wgt and hgt, categorized into OW/OB using IOTF cut-offs Household social class (Irish Central Statistics office) Early life (maternal prenatal smoking and alcohol consumption, duration of breastfeeding, weaning); child diet (dietary quality index); screen time/media exposure (television and DVD use) Moderate Lu et al, 2020, UK [ 43 ] n = 15,996, age: 3, 5, 7, 11 and 14 years, 48.3% female Longitudinal, home visit interviews (PCG) (MCS) Objectively measured wgt and hgt, defining OB and OB using both IOTF and WHO criteria; OW & OB: 28.5% (IOTF); 35% (WHO) Maternal education, family income Ethnicity Moderate Martinson et al, 2012, UK and USA [ 37 ] US sample: FFS, n = 2,930, age 1, 3, 5 and 9 years UK sample: MCS, n = 6,816, age 3, 5, 7 and 9 years US: Longitudinal, parental hospital and home visit interviews. (FFS) UK: Longitudinal, home visit interviews (PCG) (MCS) US sample: BMI calculated from wgt and hgt at ages 3 and 9 UK sample: Objectively measured wgt and hgt, BMI calculated from wgt and hgt at ages 3 and 7; BMI categorised using CDC guidelines with 85th percentile designating OW Maternal education, family income Ethnicity; Parent-level factors (age mother immigrated (under/over 18 years)) Moderate Massion et al, 2016, UK [ 25 ] n = 11,764, age: 11 years, 48% female Longitudinal, home visit interviews (PCG) (MCS) Objectively measured wgt and hgt, defining OW/OB using IOTF criteria; 28.8% OW at age 11 Maternal education Early life factors (maternal pre-pregnancy weight, maternal prenatal smoking, BW, caesarean delivery, breastfeeding duration, weaning) Strong Mireku et al, 2020, UK [ 45 ] n = 11,714, age: 14 years, 47.6% female Longitudinal, home visit interviews (PCG) (MCS) Objectively measured wgt and hgt.…”

Associations of diarised sleep onset time, period and duration with total and central adiposity in a biethnic sample of young children: the Born in Bradford study

“…This study uniquely investigated associations of diarised sleep parameters with myriad adiposity markers in a biethnic sample of young children from a deprived urban setting, a high-risk group for sleep problems and obesity [18,19]. Sleep diaries are superior to the common practice of posing a single question to parents about their child’s ‘usual’ sleep [51].…”

“…Investigation of ethnic minority and socioeconomically impoverished populations is needed. Children of non-White ethnicity and children from deprived backgrounds have unfavourable sleeping patterns and are high-risk for early onset obesity [18,19]. We have previously shown that UK South Asian children who live in a deprived urban setting go to bed much later than White children from the same area [20].…”