The association between dietary glycemic index and load and risk of gestational diabetes mellitus: A prospective study.

AIMS

This study aimed to investigate the association between dietary GI and GL and risk of GDM in a group of pregnant women in Iran.

METHODS

A number of 812 pregnant women were recruited in their first trimester in a prospective study. A validated 117-item semi-quantitative food frequency questionnaire was used to assess usual dietary intakes of participants at study baseline. Dietary GI and GL were calculated based on earlier publications. GDM was diagnosed based on the results of a fasting plasma glucose concentration and a 50-g, 1-h oral glucose tolerance test at 24-28 weeks of gestation. Cox proportional hazards model was used to compute relative risks (RRs) and 95% confidence intervals (CI) for GDM.

RESULTS

Mean ± SD of age and BMI of study participants was 29.4 ± 4.84 y and 25.14 ± 4.08 kg/m, respectively at study baseline. Mean ± SD of dietary GI was 58 ± 7 and that of dietary GL was 176 ± 42. Overall, 28.4% (n = 231) of study population developed GDM at weeks 24-28 of pregnancy. After adjustment for potential confounding variables, we found that women in the highest tertile of dietary GL were 43% more likely to develop GDM than those in the lowest tertile (95% CI: 1.01, 2.00; P-trend = 0.03). However, no significant association was seen between dietary GI (RR for the highest tertile compared to the lowest: 0.85; 95% CI: 0.61, 1.20; P-trend = 0.37), and risk of GDM.

CONCLUSIONS

We found that women with the highest dietary GL were at a greater risk of developing GDM during pregnancy. No significant association was seen between dietary GI and risk of GDM.