Peri-conceptional diet patterns and the risk of Gestational diabetes mellitus in South Indian women.

Objective: To identify peri-conceptional diet patterns among women in Bangalore, and examine their associations with risk of gestational diabetes mellitus.
Design: BANGLES, started in June 2016, was a prospective observational study, in which women were recruited at 5-16 weeks' gestation. Peri-conceptional diet was recalled at recruitment, using a validated 224-item food frequency questionnaire. GDM was assessed by a 75-gram oral glucose tolerance test at 24-28 weeks' gestation, applying WHO 2013 criteria. Diet patterns were identified using principal component analysis and diet pattern-GDM associations were examined using multivariate logistic regression, adjusting for 'a priori' confounders.
Setting: Antenatal clinics of two hospitals, Bangalore, South India.
Participants: 785 pregnant women of varied socio-economic status.
Results: GDM prevalence was 22%. Three diet patterns were identified: a) High-diversity, urban (HDU) characterised by diverse, home-cooked and processed foods was associated with older, more affluent, better-educated and urban women; b) Rice-fried snacks-chicken-sweets (RFCS), characterised by low diet-diversity, was associated with younger, less-educated, and lower income, rural and joint families; c) Healthy, traditional vegetarian (HTV), characterised by home-cooked-vegetarian and non-processed foods was associated with less-educated, more affluent, and rural and joint families. The HDU pattern was associated with a lower GDM risk (aOR: 0.80 per SD, 95% CI: 0.64, 0.99, p=0.04) after adjusting for confounders. BMI was strongly related to GDM risk and possibly mediated diet-GDM associations.
Conclusions: The findings support global recommendations to encourage women to attain a healthy pre-pregnancy BMI and increase diet-diversity. Both healthy and unhealthy foods in the patterns indicate low-awareness about healthy foods and a need for public-education.