The impact of CREBRF rs373863828 Pacific-variant on infant body composition.

In Maori and Pacific adults, the CREBRF rs373863828 minor (A) allele is associated with increased body mass index (BMI) but reduced incidence of type-2 and gestational diabetes mellitus. In this prospective cohort study of Maori and Pacific infants, nested within a nutritional intervention trial for pregnant women with obesity and without pregestational diabetes, we investigated whether the rs373863828 A allele is associated with differences in growth and body composition from birth to 12-18 months' corrected age. Infants with and without the variant allele were compared using generalised linear models adjusted for potential confounding by gestation length, sex, ethnicity and parity, and in a secondary analysis, additionally adjusted for gestational diabetes. Carriage of the rs373863828 A allele was not associated with altered growth and body composition from birth to 6 months. At 12-18 months, infants with the rs373863828 A allele had lower whole-body fat mass [FM 1.4 (0.7) vs. 1.7 (0.7) kg, aMD -0.4, 95% CI -0.7, 0.0, P = 0.05; FM index 2.2 (1.1) vs. 2.6 (1.0) kg/m2 aMD -0.6, 95% CI -1.2,0.0, P = 0.04]. However, this association was not significant after adjustment for gestational diabetes, suggesting that it may be mediated, at least in part, by the beneficial effect of CREBRF rs373863828 A allele on maternal glycemic status.

The Pacific-specific CREBRF rs373863828 allele protects against gestational diabetes mellitus in Maori and Pacific women with obesity.

AIMS/HYPOTHESIS: The CREBRF rs373863828 minor (A) allele is associated with increased BMI but reduced prevalence of type 2 diabetes in Maori and Pacific people. Given the shared aetiology of type 2 diabetes and gestational diabetes mellitus (GDM), we tested for an association between the CREBRF rs373863828 variant and GDM. METHODS: We conducted a prospective cohort study of Maori and Pacific women nested within a nutritional intervention study for pregnant women with obesity. Women were enrolled at 12-17 weeks' gestation and underwent anthropometry and collection of buffy coats for later genetic testing. GDM was diagnosed by 75 g OGTT at 24-28 weeks' gestation using the International Association of Diabetes and Pregnancy Study Groups criteria. Genotyping was performed by real-time PCR with a custom CREBRF rs373863828 probe-set. The association between CREBRF rs373863828 and GDM was analysed separately by ethnic group using logistic regression, with effect estimates combined in a meta-analysis. RESULTS: Of 112 Maori and Pacific pregnant women with obesity, 31 (28%) carried the CREBRF rs373863828 A allele (A/G or A/A) and 35 (31%) developed GDM. Women who carried the CREBRF rs373863828 A allele did not differ in BMI when compared with non-carriers (G/G). There was a fivefold reduction in the likelihood of GDM per CREBRF rs373863828 A allele (OR 0.19 [95% CI 0.05, 0.69], p = 0.01), independent of age, BMI and family history of diabetes (adjusted OR 0.13 [95% CI 0.03, 0.53], p = 0.004). GDM was diagnosed in 10% and 40% of women with and without the CREBRF rs373863828 A allele, respectively (no woman with the A/A genotype developed GDM). CONCLUSIONS/INTERPRETATION: The CREBRF rs373863828 (A) allele is associated with reduced likelihood of GDM in Maori and Pacific women with obesity and may improve GDM risk prediction. Graphical abstract.