The relationship between dietary patterns and overweight and obesity in children of Asian developing countries: A Systematic Review

BACKGROUND: The exponential increase in prevalence of childhood obesity has become a global concern. Developing countries in Asia are at particular risk due to their stage in the epidemiological and nutrition transition.

OBJECTIVES: The review objectives were to summarize the evidence on prevalence of childhood overweight and obesity within developing countries in Asia and to synthesise the best epidemiological association between the dietary patterns of children in the developing countries in Asia and their weight status in terms of obesity.

INCLUSION CRITERIA: This review considered any studies that included children under 18 years of age who live in developing countries in Asia.This review of epidemiological association considered any analytical observational studies (case-control studies, cohort studies and analytical cross-sectional studies).The focus was to summarise the prevalence of childhood overweight and obesity within developing countries in Asia and synthesise the best available evidence on the relationship between dietary patterns as the exposure variable and childhood overweight and obesity as the outcome.

SEARCH STRATEGY: A three-step search strategy was utilised, with an initial limited search of MEDLINE, CINAHL and EMBASE to identify search terms. A second search using all identified keywords and index terms was undertaken across all included databases. Thirdly, the reference list of all identified reports and articles were searched for additional studies. Additional electronic databases searched included: ProQuest, Web of Science, and Scopus. Each database was searched from inception to September 2011, with an English language restriction.

METHODOLOGICAL QUALITY: All papers selected for retrieval were assessed independently by two reviewers using standardised critical appraisal instruments from the Joanna Briggs Institute.

DATA COLLECTION: Data was extracted from included studies by two reviewers independently using an adapted version of the standardised data extraction form from the Joanna Briggs Institute.

DATA SYNTHESIS: Meta-analysis was not possible because of the heterogeneity of studies in terms of methodology, statistical analyses and outcomes. A narrative summary of results is provided.

RESULTS: Fifteen studies were included in the review. The prevalence rates of childhood overweight and obesity in Asian developing countries ranged from 5.1% to 19.9% with no specific trend in age or gender. Several significant but inconsistent statistical associations between dietary patterns and overweight/obesity in children and adolescents were found [high energy diet (OR: 1.80 95%CI 1.10 to 2.90, p<0.05 vs 0.80 95%CI 0.60 to 1.10, p>0.05), low intake of fruit and vegetables (OR: 2.34 95%CI 1.04 to 5.24, p<0.001; 2.00 95%CI 1.10 to 3.40, p<0.05 vs 1.33 95%CI 0.44 to 4.05, p>0.05; 0.70 95%CI 0.50 to 1.00, p>0.05), high meat consumption (RR: 2.40 95%CI 1.00 to 5.60, p<0.05 vs 1.70 95%CI 1.00 to 2.70, p>0.05), eating out (OR: 12.0 95%CI 7.7 to 18.7, p<0.001; 1.70 95%CI 1.04 to 2.90, p<0.05 vs 1.20 95%CI 0.60 to 2.40, p>0.05), fast food intake (OR: 1.50 95%CI 1.12 to 2.02, p<0.05), presence of snacking (OR: 2.34 95%CI 1.01 to 5.54, p=0.05; 1.26 95%CI 1.13 to 1.40, p<0.05 vs 0.80 95%CI 0.48 to 1.32,p=0.377; 0.60 95%CI 0.30 to 0.99, p<0.05; 0.60 95%CI 0.40 to 0.90, p<0.05) and drinking sugar sweetened beverages (OR: 1.60 95%CI 1.02 to 2.50, p<0.05; 1.70 95%CI 1.10 to 2.70, p<0.05 vs 0.93 95%CI 0.82 to 1.05, p>0.05)]. The key limitation was the heterogeneity of studies in terms of measures of dietary patterns and obesity standards.

CONCLUSIONS: The prevalence rates of childhood overweight and obesity in Asian developing countries ranged from 5.1% to 19.9% with no specific trend in age or gender. From the practice perspective, several significant yet inconsistent statistical associations between dietary patterns and childhood overweight/obesity in children and adolescents were found.This review highlights the need for clinicians to monitor the effects of dietary change on the weight and health status of children in Asian countries.There is a need for valid measures of dietary intake and use of standardised international cut-offs for overweight and obesity, and for future researchers to conduct prospective studies to determine the causal relationship between Asian children's dietary pattern and their weight status.