Effects of dietary and physical activity interventions on the risk of type 2 diabetes in South Asians: meta-analysis of individual participant data from randomised controlled trials.
AIMS/HYPOTHESIS
Individuals of South Asian origin have a high risk of type 2 diabetes and of dying from a diabetes-attributable cause. Lifestyle modification intervention trials to prevent type 2 diabetes in high-risk South Asian adults have suggested more modest effects than in European-origin populations. The strength of the evidence of individual studies is limited, however. We performed an individual participant data meta-analysis of available RCTs to assess the effectiveness of lifestyle modification in South Asian populations worldwide.


METHODS
We searched PubMed, EMBASE, Cochrane Library and Web of Science (to 24 September 2018) for RCTs on lifestyle modification interventions incorporating diet and/or physical activity in South Asian adults. Reviewers identified eligible studies and assessed the quality of the evidence. We obtained individual participant data on 1816 participants from all six eligible trials (four from Europe and two from India). We generated HR estimates for incident diabetes (primary outcome) and mean differences for fasting glucose, 2 h glucose, weight and waist circumference (secondary outcomes) using mixed-effect meta-analysis overall and by pre-specified subgroups. We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to rate the quality of evidence of the estimates. The study is registered with the International Prospective Register of Systematic Reviews ([PROSPERO] CRD42017078003).


RESULTS
Incident diabetes was observed in 12.6% of participants in the intervention groups and in 20.0% of participants in the control groups. The pooled HR for diabetes incidence was 0.65 (95% CI 0.51, 0.81; I2 = 0%) in intervention compared with control groups. The absolute risk reduction was 7.4% (95% CI 4.0, 10.2), with no interactions for the pre-specified subgroups (sex, BMI, age, study duration and region where studies were performed). The quality of evidence was rated as moderate. Mean difference for lifestyle modification vs control groups for 2 h glucose was -0.34 mmol/l (95% CI -0.62, -0.07; I2 = 50%); for weight -0.75 kg (95% CI -1.34, -0.17; I2 = 71%) and for waist -1.16 cm (95% CI -2.16, -0.16; I2 = 75%). No effect was found for fasting glucose. Findings were similar across subgroups, except for weight for European vs Indian studies (-1.10 kg vs -0.08 kg, p = 0.02 for interaction).


CONCLUSIONS/INTERPRETATION
Despite modest changes for adiposity, lifestyle modification interventions in high-risk South Asian populations resulted in a clinically important 35% relative reduction in diabetes incidence, consistent across subgroups. If implemented on a large scale, lifestyle modification interventions in high-risk South Asian populations in Europe would reduce the incidence of diabetes in these populations.
['Jenum|Anne Karen|AK|', 'Brekke|Idunn|I|', 'Mdala|Ibrahimu|I|', 'Muilwijk|Mirthe|M|', 'Ramachandran|Ambady|A|', 'Kjøllesdal|Marte|M|', 'Andersen|Eivind|E|', 'Richardsen|Kåre R|KR|', 'Douglas|Anne|A|', 'Cezard|Genevieve|G|', 'Sheikh|Aziz|A|', 'Celis-Morales|Carlos A|CA|', 'Gill|Jason M R|JMR|', 'Sattar|Naveed|N|', 'Bhopal|Raj S|RS|', 'Beune|Erik|E|', 'Stronks|Karien|K|', 'Vandvik|Per Olav|PO|', 'van Valkengoed|Irene G M|IGM|']
D050154:Adiposity D000328:Adult D000368:Aged D000369:Aged, 80 and over D044466:Asians D001786:Blood Glucose D015992:Body Mass Index D001835:Body Weight D003924:Diabetes Mellitus, Type 2 D004032:Diet D005060:Europe D015444:Exercise D005260:Female D006801:Humans D015994:Incidence D007194:India D008019:Life Style D008297:Male D008875:Middle Aged D008957:Models, Genetic D009765:Obesity D016032:Randomized Controlled Trials as Topic D018570:Risk Assessment
Physical activity Type 2 diabetes South Asians Prevention Individual participant data meta-analysis RCT Diet Lifestyle intervention