Associations of maternal insulin sensitivity during pregnancy with childhood central adiposity in the Genetics of Glucose regulation in Gestation and Growth (Gen3G) cohort.

BACKGROUND: Childhood obesity has been associated with prenatal exposure to maternal hyperglycaemia, but we lack understanding about maternal insulin physiologic components that contribute to this association. OBJECTIVES: Evaluate the association between maternal insulin sensitivity during pregnancy and adiposity measures in childhood. METHODS: In 422 mother-child pairs, we tested associations between maternal insulin sensitivity measures at ~26 weeks of pregnancy and child adiposity measures, including dual-energy X-ray absorptiometry body composition and anthropometry (body mass index and waist circumference) at ~5 years. We used linear regression analyses to adjust for maternal age, ethnicity, gravidity, first-trimester body mass index, and child sex and age at mid-childhood. RESULTS: In early pregnancy, maternal mean age was 28.6 ± 4.3 years and median body mass index was 24.1 kg/m2 . Lower maternal insulin sensitivity indices were correlated with greater child adiposity based on anthropometry measures and on dual-energy X-ray absorptiometry total and trunk % fat in univariate associations (r = -0.122 to -0.159). Lower maternal insulin sensitivity was specifically associated with higher dual-energy X-ray absorptiometry trunk % fat (n = 359 for Matsuda; ß = -0.034 ± 0.013; p = 0.01) after adjustment for covariates, including maternal body mass index. CONCLUSIONS: Maternal insulin sensitivity during pregnancy may contribute to increased risk for higher offspring central adiposity in middle childhood.

Associations between Cord Blood Leptin Levels and Childhood Adiposity Differ by Sex and Age at Adiposity Assessment.

Lower cord blood leptin levels have been associated with lower and higher adiposity in childhood and associations seem to differ according to the child's age, methods of adiposity assessment and sex. Our aim was to investigate sex-specific associations of cord blood leptinemia with childhood adiposity at birth, 3 and 5 years of age. We measured cord blood leptin using Luminex immunoassays in 520 offspring from the Gen3G cohort. We tested associations between cord blood leptin and body mass index (BMI) z-score, skinfolds thicknesses (SFT), and body composition using dual-energy X-ray absorptiometry, adjusted for confounders. At birth, girls had almost twice as much leptin in cord blood as boys (15.5 [8.9; 25.6] vs. 8.6 [4.9; 15.0] ng/mL; p < 0.0001) as well as significantly greater adiposity. Lower levels of cord blood leptin were associated with higher sum of SFT (ß = −0.05 ± 0.02; p = 0.03) and higher BMI z-score (ß= −0.22 ± 0.08; p = 0.01) in 3-year-old boys only. We did not observe these associations at age 5, or in girls. Our results suggest a sexual dimorphism in the programming of leptin sensitivity and childhood adiposity, but further observational and functional studies are needed to better understand the role of leptin in early life.

Maternal glucose in pregnancy is associated with child's adiposity and leptin at 5 years of age.

BACKGROUND: Exposure to maternal hyperglycaemia in pregnancy has been associated with childhood obesity. Leptin regulation might be involved in this 'adiposity programming' and may depend on timing of exposure. OBJECTIVES: To investigate associations of maternal glycaemia at different periods in pregnancy with childhood adiposity and leptin levels at 5 years of age. METHODS: In a prospective pre-birth cohort, we measured maternal glucose levels after a 50 g oral glucose challenge test at first trimester (9.8 ± 2.3 weeks) and during a 75 g oral glucose tolerance test at second trimester (26.5 ± 0.9 weeks). We followed up children at 5 years; we measured anthropometry and body composition using dual-energy X-ray absorptiometry (DXA). We measured fasting leptin levels using immunoassays (Luminex) in 328 children. We conducted linear regression analyses, adjusting for potential confounders. RESULTS: Maternal glycaemia at first trimester was associated with childhood leptin levels at 5 years, independently of maternal pre-pregnancy BMI and other confounders (ß = .09 ± .04; P = .03). Higher post-load glucose levels at second trimester were associated with greater total body fat percentage measured by DXA (1 hour-glucose: ß = .010 ± .004; P = .03 and 2 hours-glucose: ß = .016 ± .005; P = .002), but not with leptin levels. CONCLUSIONS: Our results suggest that programming of leptin regulation may be sensitive to maternal hyperglycaemia specifically in early pregnancy.