The effectiveness of lifestyle interventions on type 2 diabetes and gestational diabetes incidence and cardiometabolic outcomes: a systematic review and meta-analysis of evidence from low- and middle-income countries

Background: As lifestyle modification offers a unique strategy to prevent diabetes, we evaluated the effectiveness of lifestyle interventions in the prevention of type 2 diabetes and gestational diabetes in low- and middle-income countries (LMICs).

Methods: We did a systematic literature review and meta-analysis. We searched MEDLINE, Embase, Web of Science, and Cochrane Library for randomised controlled trials published in English, Spanish, French, and Portuguese between 1 January 2000 and 15 June 2022, evaluating multi-target and multi-component lifestyle interventions in at-risk populations conducted in LMICs. The main outcomes were incidence of type 2 diabetes and gestational diabetes, and indicators of glycaemic control. We assessed the methodological quality of the studies using the Cochrane risk of bias tool. Inverse-variance random-effects meta-analyses estimated the overall effect sizes. Sources of heterogeneity and study bias were evaluated. The study protocol was registered in PROSPERO (CRD42021279174).

Findings: From 14 330 abstracts, 48 (0·3%) studies with 50 interventions were eligible of which 56% were conducted in lower-middle-income countries, 44% in upper-middle, and none in low-income. 54% of the studies were assessed as moderate risk of bias and 14% as high risk. A median of 246 (IQR 137-511) individuals participated in the interventions with a median duration of 6 (3-12) months. Lifestyle interventions decreased the incidence risk ratio of type 2 diabetes by 25% (0·75 [95% CI 0·61 to 0·91]), and reduced the levels of HbA1c by 0·15% [-0·25 to -0·05], fasting plasma glucose by 3·44 mg/dL [-4·72 to -2·17], and 2-hr glucose tolerance by 4·18 mg/dL [-7·35 to -1·02]. No publication bias was suggested for these outcomes. High levels of heterogeneity (I²≥ 81%) were found in most meta-analyses. Exploration using meta-regressions could not identify any explanatory variable, except for fasting glucose for which the quality score of the articles seems to be an effect modifier decreasing slightly the heterogeneity (72%) in the low risk of bias pooled estimate. The effect on gestational diabetes could not be evaluated due to the scarcity of available studies.

Interpretation: Comprehensive lifestyle interventions are effective strategies to prevent type 2 diabetes among at-risk populations in LMICs. The heterogeneity identified in our results should be considered when using these interventions to address the onset of type 2 diabetes.

Funding: None.