Inverse associations between the dietary diabetes risk reduction score and dietary phytochemical index with metabolic syndrome and its components: a cross-sectional analysis of the Fasa adult cohort study in rural Iran
Authors
Affiliations
- 1Student Research Committee, Fasa University of Medical Sciences, Fasa, Iran.
- 2USERN Office, Fasa University of Medical Sciences, Fasa, Iran.
- 3Department of Biology, College of Science for Women, University of Babylon, Hila, Iraq.
- 4Endocrinology and Metabolism Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran.
- 5Department of Nutrition, School of Public Health, Zanjan University of Medical Sciences, Zanjan, 45139–56184, Iran. rahimlum@gmail.com.
- 6Noncommunicable Diseases Research Center, Fasa University of Medical Sciences, Fasa, 74616-86688, Iran. kmsrc89@gmail.com.
- 7Clinical Research Development Unit, Valiasr Hospital, Fasa University of Medical Sciences, Fasa, Iran. kmsrc89@gmail.com.
Background: The Dietary Diabetes Risk Reduction Score (DDRRS) and Dietary Phytochemical Index (DPI) are evidence-based tools for assessing diabetes-preventive and phytochemical-rich diets. Yet, their combined associations with metabolic syndrome (MetS) remain underexplored in rural settings. This study aimed to investigate the relationships of DDRRS and DPI with MetS and its components among rural Iranian adults.
Methods: This cross-sectional study utilized baseline data from the Fasa Adults Cohort Study (FACS), a large rural Iranian cohort involving 10,138 Iranian adults aged 35-70 years living in rural areas of Fasa County, southern Iran. MetS was defined via the Joint Interim Statement criteria. Dietary intake was assessed via a validated 125-item food frequency questionnaire. The DDRRS (range: 8-32) and DPI (percentage of energy from phytochemical-rich foods) were calculated. After adjusting for the most important variables, multivariable logistic regression models estimated odds ratios (ORs) and 95% confidence intervals (CIs) for MetS and its components. Subgroup and sensitivity analyses were subsequently performed.
Results: The MetS prevalence was 38.4%. Participants in the highest DDRRS quartile had 62% lower odds of MetS (OR: 0.38; 95% CI: 0.32-0.45; P-trend < 0.001) compared to the lowest quartile. Similarly, the highest DPI quartile was associated with 53% reduced odds (OR: 0.47; 95% CI: 0.40-0.55; P-trend < 0.001). The strongest protective effects were observed for central obesity (DDRRS OR: 0.35; DPI OR: 0.41) and hyperglycemia (DDRRS OR: 0.37; DPI OR: 0.49). Participants with joint high adherence (both DDRRS and DPI in the highest quartile, Q4) had 72% lower odds of MetS (OR 0.28; 95% CI: 0.23-0.34) compared to those in the lowest quartile of both scores. Subgroup analyses stratified by sex, body mass index (BMI ≥ 25 vs. <25 kg/m²), age (< 50 vs. ≥50 years), and smoking status showed stronger inverse associations in women and overweight/obese individuals, with no significant interactions (all P-interaction > 0.05).
Conclusions: Higher DDRRS and DPI adherence was inversely associated with MetS in rural Iranian adults, with potential synergistic effects when both are high. These cross-sectional findings highlight promising dietary patterns for further investigation and possible future interventions in comparable settings.
Clinical trial number: Not applicable.
Keywords: Dietary diabetes risk reduction score; Dietary phytochemical index; Iran; Metabolic syndrome; Rural cohort.
