The impact of a culturally adapted lifestyle intervention on the glycaemic profile of mothers with GDM one year after delivery - a community-based, cluster randomized trial in Sri Lanka.

Background: A woman with a history of GDM has a high risk of developing type two diabetes (T2DM) in her future life. Lifestyle modifications are known to attenuate the progression of GDM to T2DM. Therefore, the aim of this study was to assess the impact of a simple, cost effective, culturally acceptable lifestyle intervention programme on the trajectory towards T2DM in women with a history of GDM.

Methods: This cluster randomized trial was conducted in 100 postpartum women in three selected districts of Sri Lanka. The subjects were divided into intervention (n = 50) and control groups (n = 50) by cluster randomization method. A culturally adapted protocol (comprised of dietary and physical activity modifications) was administered to the intervention group. The glycemic profile was assessed using fasting and 2-hour post-OGTT plasma glucose and HbA1c, and insulin resistance by HOMA-IR at baseline and after one year of intervention.

Results: The mean age (SD) of the subjects in the intervention and control groups were 33.0 (5.1) and 34.3 (6.5) years respectively. All glycemic and insulin resistance parameters (i.e. Fasting plasma glucose- FPG, 2-hour post-OGTT plasma glucose, HbA1c and HOMA-ir) were comparable (p > 0.05) between the two groups at baseline. FPG, 2 h post OGTT, HbA1c and HOMA-ir values between intervention vs. control (p) at 12 months were 87.3 vs. 123.2 (< 0.01); 106.5 vs. 156.1 (0.01); 5.3 vs. 6.8 (< 0.01) and 0.9 vs. 2.3 (< 0.01) respectively. All glycemic parameters showed a significant reduction in the intervention group at 12 months compared to baseline. In contrast, the control group showed a significant increase in FPG, 2-hour post-OGTT plasma glucose and HbA1c at 12 months compared to baseline. In multiple linear regression model adjusted for age, parity and family history, the control group showed an approximately 33 times risk of developing insulin resistance compared to the intervention group.

Conclusion: The culturally acceptable and individualized lifestyle intervention was able to produce remarkable reductions in glycaemic and insulin resistance parameters among postpartum women with a history of GDM.

Trial registration: Ethical clearance was obtained from the Ethics Review Committee of the University of Sri Jayewardenepura, Sri Lanka (ERC 52/14), Sri Lanka Clinical trial registration number Sri Lanka Clinical Trials Registry (SLCTR/2015/021 date 25.09.2015).