Risk factors of overweight and obesity in childhood and adolescence in South Asian countries: a systematic review of the evidence.

OBJECTIVE
To assess and synthesize the published evidence on risk factors of overweight and obesity in childhood and adolescence in South Asia.

STUDY DESIGN
A systematically conducted narrative review.

METHODS
A systematic review was conducted of all primary studies published between January 1990 and June 2013 from India, Pakistan, Nepal, Bangladesh, Sri Lanka, Bhutan, and Maldives located through the following data bases: PubMed, PubMed central, EMBASE, MEDLINE, BioMed central, Directory of Open Access Journals (DOAJ) and electronic libraries of the authors' institutions. Data extraction and quality appraisal of included studies was done independently by two authors and findings were synthesized in a narrative manner as meta-analysis was found to be inappropriate due to heterogeneity of the included studies.

RESULTS
Eleven primary studies were included in the final review, all of which were conducted in school settings in India, Pakistan and Bangladesh. Prevalence of overweight and obesity showed wide variations in the included studies. The key individual risk factors with statistically significant associations to overweight and obesity included: lack of physical activities reported in six studies; prolonged TV watching/playing computer games reported in four studies; frequent consumption of fast food/junk food reported in four studies; and frequent consumption of calorie dense food items reported in two studies. Family level risk factors included higher socioeconomic status reported in four studies and family history of obesity reported in three studies.

CONCLUSION
This review provides evidence of key contributors to the increasing burden of obesity and overweight among children and adolescents in South Asia, and demonstrates the nutritional transition that characterizes other developing countries and regions around the world. The findings have implications for policy, practice and the development of interventions at various levels to promote healthy eating and physical activity among children and adolescents in the region as well as more globally.