ESPE Abstracts

Introduction: With the increasing prevalence of obesity, prediabetes and type 2 diabetes (T2D) in youth are on the rise. Prevention is paramount for these multifactorial diseases. Dietary interventions targeting a reduction of dietary glycemic index (GI) and glycemic load (GL) are potential strategies for improving insulin resistance. However, the association between GI and GL and T2D risk in children remains uncertain.

Objectives: To investigate cross-sectional and prospective associations between dietary GI and GL among children recruited at 8-10 y and insulin dynamics, from childhood to late adolescence.

Methods: We used data from the QUébec Adipose and Lifestyle Investigation in Youth (QUALITY) Cohort, an ongoing study of 630 Caucasian children with a parental history of obesity in Québec (Canada). Children were evaluated at three timepoints: baseline (8-10y, n=630), first follow-up (10-12y, n=564) and second follow-up (15-17y, n=377). Dietary habits were evaluated using three non-consecutive 24h-dietary recalls (including one weekend day) at baseline. Daily average GI was calculated using the International Table of GI Values; GL was obtained by multiplying GI by the available carbohydrate content in each food. Insulin sensitivity was measured using the Matsuda Insulin Sensitivity Index. Insulin secretion was calculated as the ratio of the area under the curve of insulin to glucose over 30 min (1st phase) and 120 min (2nd phase) during an oral glucose tolerance test. Multivariable linear regression models were adjusted for baseline age, sex, pubertal status, body mass index z-score, physical activity (accelerometry), screen time (questionnaire), the Diet Quality Index-International, and an indicator variable capturing participant underreporting of food intake (based on the Goldberg equation for energy requirements). Sensitivity analyses included associations stratified by weight status.

Results: At baseline, 46% of participants were girls, 78% were prepubertal and 43% had overweight/obesity. A one unit increase in GL at baseline was associated cross-sectionally with 0.28% lower insulin sensitivity (95% CI -0.50% to -0.06%) and 0.14% higher 2nd phase insulin secretion (95% CI 0.01% to 0.28%). We observed no meaningful associations between GI/GL at baseline and insulin sensitivity or insulin secretion at 10-12y nor at 15-17y. Among children with overweight/obesity, those with higher GI at baseline had a 2.1% higher 2nd phase insulin secretion at 10-12 yrs (95% CI -0.26% to 4.5%), albeit not reaching statistical significance.

Conclusion: Although lower GI and GL diets were associated with slightly better insulin dynamics in cross-sectional analyses, these results were not observed longitudinally.