Association of the Pro12Ala and C1431T variants of PPARgamma and their haplotypes with susceptibility to gestational diabetes.

International audienceBACKGROUND: The protective role of the Ala allele in the Pro12Ala polymorphism of PPARγ on type 2 diabetes has been well established but not confirmed in the context of pregnancy, for gestational diabetes, a known predictor of later type 2 diabetes onset. Another PPARγ polymorphism, the C1431T, is in strong linkage disequilibrium with Pro12Ala and has been shown to be associated with body weight, but its association with diabetes is controversial. RESEARCH DESIGN AND METHODS: In 1708 women of the EDEN mother-child cohort, the PPARγ Pro12Ala and C1431T polymorphisms were genotyped and analyzed in association with maternal prepregnancy body mass index, obesity before pregnancy, and gestational diabetes, separately and also combined in haplotypes. RESULTS: The prevalence of obesity was significantly higher in mothers with the Ala/Ala genotype compared with carriers of the Pro allele (35 vs. 9%, P < 0.0001), but there was no cases of gestational diabetes in Ala/Ala mothers. Mothers homozygous for the T allele of C1431T were also more obese (24 vs. 9%, P = 0.035), and three times more had gestational diabetes (18 vs. 6%, P = 0.044). Frequencies of haplotypes for these two single-nucleotide polymorphisms differed significantly in mothers with and without gestational diabetes; in comparison with the Pro-C haplotype, the Pro-T haplotype conferred the highest risk [odds ratio (95% CI) = 1.89 (1.05-3.40)], and the Ala-C the lowest risk [odds ratio (95% CI) = 0.12 (0.52-1.70)]. CONCLUSIONS: These results from a haplotype analysis, show for the first time that genetic variations in the PPARγ gene could play a role in the susceptibility to develop gestational diabetes

Early growth characteristics and the risk of reduced lung function and asthma: A&nbsp;meta-analysis of 25,000 children.

BACKGROUND: Children born preterm or with a small size for gestational age are at increased risk for childhood asthma. OBJECTIVE: We sought to assess the hypothesis that these associations are explained by reduced airway patency. METHODS: We used individual participant data of 24,938 children from 24 birth cohorts to examine and meta-analyze the associations of gestational age, size for gestational age, and infant weight gain with childhood lung function and asthma (age range, 3.9-19.1 years). Second, we explored whether these lung function outcomes mediated the associations of early growth characteristics with childhood asthma. RESULTS: Children born with a younger gestational age had a lower FEV1, FEV1/forced vital capacity (FVC) ratio, and forced expiratory volume after exhaling 75% of vital capacity (FEF75), whereas those born with a smaller size for gestational age at birth had a lower FEV1 but higher FEV1/FVC ratio (P&nbsp;&lt; .05). Greater infant weight gain was associated with higher FEV1 but lower FEV1/FVC ratio and FEF75 in childhood (P&nbsp;&lt; .05). All associations were present across the full range and independent of other early-life growth characteristics. Preterm birth, low birth weight, and greater infant weight gain were associated with an increased risk of childhood asthma (pooled odds ratio, 1.34 [95% CI, 1.15-1.57], 1.32 [95% CI, 1.07-1.62], and 1.27 [95% CI, 1.21-1.34], respectively). Mediation analyses suggested that FEV1, FEV1/FVC ratio, and FEF75 might explain 7% (95% CI, 2% to 10%) to 45% (95% CI, 15% to 81%) of the associations between early growth characteristics and asthma. CONCLUSIONS: Younger gestational age, smaller size for gestational age, and greater infant weight gain were across the full ranges associated with childhood lung function. These associations explain the risk of childhood asthma to a substantial extent

Early growth characteristics and the risk of reduced lung function and asthma: A meta-analysis of 25,000 children.

BACKGROUND: Children born preterm or with a small size for gestational age are at increased risk for childhood asthma. OBJECTIVE: We sought to assess the hypothesis that these associations are explained by reduced airway patency. METHODS: We used individual participant data of 24,938 children from 24 birth cohorts to examine and meta-analyze the associations of gestational age, size for gestational age, and infant weight gain with childhood lung function and asthma (age range, 3.9-19.1 years). Second, we explored whether these lung function outcomes mediated the associations of early growth characteristics with childhood asthma. RESULTS: Children born with a younger gestational age had a lower FEV1, FEV1/forced vital capacity (FVC) ratio, and forced expiratory volume after exhaling 75% of vital capacity (FEF75), whereas those born with a smaller size for gestational age at birth had a lower FEV1 but higher FEV1/FVC ratio (P < .05). Greater infant weight gain was associated with higher FEV1 but lower FEV1/FVC ratio and FEF75 in childhood (P < .05). All associations were present across the full range and independent of other early-life growth characteristics. Preterm birth, low birth weight, and greater infant weight gain were associated with an increased risk of childhood asthma (pooled odds ratio, 1.34 [95% CI, 1.15-1.57], 1.32 [95% CI, 1.07-1.62], and 1.27 [95% CI, 1.21-1.34], respectively). Mediation analyses suggested that FEV1, FEV1/FVC ratio, and FEF75 might explain 7% (95% CI, 2% to 10%) to 45% (95% CI, 15% to 81%) of the associations between early growth characteristics and asthma. CONCLUSIONS: Younger gestational age, smaller size for gestational age, and greater infant weight gain were across the full ranges associated with childhood lung function. These associations explain the risk of childhood asthma to a substantial extent