Association of maternal exposures with adiposity at age 4/5 years in white British and Pakistani children: findings from the Born in Bradford study

Abstract

Aims/hypothesis: There is evidence that, from birth, South Asians are fatter, for a given body mass, than Europeans. The role of developmental overnutrition related to maternal adiposity and circulating glucose in these ethnic differences is unclear. Our aim was to compare associations of maternal gestational adiposity and glucose with adiposity at age 4/5 years in white British and Pakistani children.

Methods: Born in Bradford is a prospective study of children born between 2007 and 2010 in Bradford, UK. Mothers completed an OGTT at 27-28 weeks of gestation. We examined associations between maternal gestational BMI, fasting glucose, post-load glucose and diabetes (GDM) and offspring height, weight, BMI and subscapular skinfold (SSF) and triceps skinfold (TSF) thickness at age 4/5 years, using data from 6060 mother-offspring pairs (2717 [44.8%] white British and 3343 [55.2%] Pakistani).

Results: Pakistani mothers had lower BMI and higher fasting and post-load glucose and were twice as likely to have GDM (defined using modified WHO criteria) than white British women (15.8% vs 6.9%). Pakistani children were taller and had lower BMI than white British children; they had similar SSF and lower TSF. Maternal BMI was positively associated with the adiposity of offspring in both ethnic groups, with some evidence of stronger associations in Pakistani mother-offspring pairs. For example, the difference in adjusted mean BMI per 1 kg/m² greater maternal BMI was 0.07 kg/m² (95% CI 0.05, 0.08) and 0.10 kg/m² (95% CI 0.09. 0.11) in white British and Pakistani children, respectively, with equivalent results for SSF being 0.07 mm (95% CI 0.05, 0.08) and 0.09 mm (95% CI 0.08. 0.11) (p for ethnic difference < 0.03 for both). There was no strong evidence of association of fasting and post-load glucose, or GDM, with outcomes in either group.

Conclusions/interpretation: At age 4/5 years, Pakistani children are taller and lighter than white British children. While maternal BMI is positively associated with offspring adiposity, gestational glycaemia is not clearly related to offspring adiposity in either ethnic group.

Keywords: Adiposity; Children; Pregnancy glycaemia; South Asian.

Fig. 1

Study flow chart. ‘Unknown’ indicates no data available for these cases

Fig. 2

Differences in mean offspring size and adiposity between Pakistani and white British infants. Black circles, unadjusted differences in means comparing Pakistani with white British (with positive differences suggesting higher levels in Pakistani children on average); white circles, additional adjustment for birthweight. 95% CIs are indicated by capped vertical lines. Analyses are based on the multiple imputed datasets

Fig. 3

Adjusted associations of maternal pregnancy exposures with offspring variables at age 4/5 years. Data show the difference in means per unit increase in maternal BMI, fasting glucose and post-load glucose, comparing offspring whose mothers (circles, white British; triangles, Pakistani) had GDM with those who did not. 95% CIs are indicated by capped horizontal lines. Analyses were based on the multiple imputed datasets. (a) Adjusted associations of maternal pregnancy exposures with offspring height (cm), weight (kg) and BMI at age 4/5 years. Results are adjusted for child sex, age at child measurement, maternal age, parity, BMI (for maternal fasting and post-load glucose and GDM), maternal height (when the outcome was offspring height) and education, housing tenure, whether anyone in the household was in receipt of means tested benefits, and smoking (model 2). (b) Association of maternal pregnancy exposures with offspring SSF (mm) and TSF (mm) thickness at age 4/5 years. Results are adjusted for sex, age at child measurement, maternal age, parity, BMI (for maternal fasting and post-load glucose and GDM) and education, housing tenure, whether anyone in the household was in receipt of means tested benefits, and smoking (model 2) with further adjustment for offspring BMI (model 3)