iHEALTH-T2D - Family-based intervention to improve healthy lifestyle and prevent Type 2 Diabetes amongst South Asians with central obesity and prediabetes

Background

The family environment is an important determinant of metabolic health, a hypothesis which is supported by the clustering of obesity and T2D in South Asian families. Recent studies suggest that a lifestyle intervention that targets the family environment is effective at achieving weight loss amongst South Asians with IGT in Europe, but this has not yet been extended to prevention of T2D.

The iHEALTH-T2D team developed and evaluated a family-based intervention for health promotion amongst UK South Asians with central obesity. The intervention is closely based on established, successful protocols for prevention of T2D through weight loss in Europeans, but has been culturally adapted for South Asians (e.g. detailed food composition tables that capture customary diet, and translation of materials into relevant languages). The aim was for the family to take joint responsibility for change to a healthy lifestyle, supporting and guiding the obese index case in making healthy choices, and maintaining long-term engagement in the lifestyle intervention program. The target is for the index case to avoid new onset of T2D as defined by the primary endpoint, through a combination of reduced calorific intake, lower consumption of fat and refined sugars, and increased physical activity (150 minutes of moderate physical activity per week). Family members are also encouraged to make healthier choices.

Aims

Primary research aim: Determine whether a family-based lifestyle modification delivered by community health workers vs usual care is clinically- and cost-effective for prevention and risk reduction of T2D.

Secondary research aims: Assess effects on adiposity measures, glucose metabolism and other measures of well-being in the index case and family members.

Project plan

The goal was to develop approaches to health promotion through lifestyle modification (healthy diet, increased physical activity) that are acceptable, effective and efficient for prevention of T2D in South Asian communities from diverse settings, for scale-up across the Indian subcontinent and Europe.

iHealth-T2D studied men and women from the Indian subcontinent (India, Pakistan and Sri Lanka), as well as Europe (UK) to provide evidence about the implementation of lifestyle modifications in both high and low income settings. The team used focus groups, and the experience and knowledge of local leaders and local experts to develop approaches that are culturally appropriate, acceptable, sustainable and scalable amongst all segments of the community.

The team aimed to determine the factors that influenced participation in and benefit from health promotion. The team also aimed to undertake health economic analysis of the approaches to implementation of lifestyle modification, including assessment of incremental value, and potential ethical, legal, regulatory, social and economic implications of scaling up at the local, regional and national levels.

The project aimed to provide evidence for local and national experts and policy makers to scale up the intervention in a sustainable way, and to translate and embed the findings from our research into clinical practice and policy, and thereby help reverse the epidemic of T2D amongst South Asians.

The secondary objectives of the study were to:

Engage local investigators and local communities in adapting our established protocols for use amongst South Asians on the Indian subcontinent;
Analyse the data to determine whether family-based lifestyle modification vs usual care reduces risk of T2D (primary endpoint) and compare effectiveness of the intervention between groups, amongst South Asians with:
i. central obesity;
ii. prediabetes and
iii.overall (with central obesity and / or obesity).

Investigate secondary endpoints, including health gains in family members. Identify social, demographic and environmental factors influencing primary and secondary endpoints.
Carry out a health economic analysis of family-based lifestyle modifications vs usual care for prevention of T2D on the Indian subcontinent and Europe. Quantify the cost-effectiveness of screening by waist circumference vs HbA1c. Assess incremental value, and potential ethical, legal, regulatory, social and economic implications of scaling up locally and nationally.
Disseminate and exploit the findings. Engage local and national experts and policy makers in translating and embedding the findings into practice and policy.

Publications and output

GACD have also an end-of-programme report providing a comprehensive summary of the programme and outcomes.

Principal investigators

John Chambers Imperial College London, United Kingdom

Team members

Gary Frost Imperial College London, United Kingdom
Ninha Silva Imperial College London, United Kingdom
Jaspal Kooner Imperial College London, United Kingdom
Sujeet Jha Devki Devi Foundation, India
Prasad Katulanda University of Colombo, Sri Lanka
Rajitha Wickremasinghe University of Kelaniya, Sri Lanka
Graham Cookson University of Surrey, United Kingdom
Ravindra Rannan-Eliya Institute of Health Policy, Sri Lanka
Karien Stronks University of Amsterdam, Netherlands
Marjo-Riitta Jarvelin University of Oulu, Finland
Sajjad Ahmad Punjab Institute of Cardiology, Pakistan
Khadija Irfan Khawaja Services Institute of Medical Sciences, Pakistan