Dietary approach to stop hypertension and obesity among Iranian adults: Yazd health study-TAMYZ and Shahedieh cohort

Abstract

Purpose Established data revealed a relationship between obesity and increasing the risk of mortality and morbidity of chronic diseases. There are conflicting data regarding the association between adherence of dietary approach to stop hypertension (DASH) and obesity. Therefore, this study aims to investigate this relationship among a large sample of Iranian adults. Design/methodology/approach This cross-sectional study was performed by 10,693 individuals; 6750 individuals related to Yazd Health Study living in the urban area and 3943 individuals related to Shahedieh cohort study living in the suburb area. Dietary intake was evaluated by using a validated food frequency questionnaire. In all participants, anthropometric indices including body mass index were measured. The DASH score was considered using gender-specific quintiles of DASH items. To evaluate the relationship of DASH diet and obesity, multivariate logistic regression analysis was used. Findings By adjusting confounders, participants in highest quintiles of DASH diet were compared to the lowest have lower odds of obesity in suburb area (odds ratio [OR]: 0.78; 95% confidence interval [CI]: 0.63, 0.96), in urban (OR: 0.71; 95% CI: 0.52, 0.99) and in whole population of both studies (OR: 0.75; 95% CI: 0.63, 0.90). Besides, more compliance of women to this diet in urban (OR: 0.64; 95% CI: 0.48, 0.85) and population of both studies (OR: 0.77; 95% CI: 0.62, 0.96) were associated with reduced odds of central obesity. Research limitations/implications Considering this study limitations, the following can be mentioned: in this cross-sectional study, the causal relationship between DASH diet and obesity could not be assessed. Consequently, further prospective studies are required in this area. Second, although a valid food frequency questionnaire was used, but there was a measurement error and an error in the classification of people participating in the study. Moreover, we cannot reject the possibility of residual confounding bias because unknown or unmeasured confounders may exist that affected our results. Finally, our participants with odds of obesity might have been advised to reduce their fat intake, which led them to alter their dietary habits. However, such possibility cannot be resolved in a cross-sectional study. Originality/value DASH dietary pattern could decrease odds of obesity in both urban and suburb area and central obesity in urban area only. Further prospective studies are needed for causal conclusion.