Predicting of changes in obesity indices regarding to dietary patterns in longitudinal Tehran lipid and glucose study

Introduction: This study aimed at investigating the association between obesity indices (Body Mass Index (BMI), Waist Circumference (WC), Waist to Hip Ratio (WHR)) and dietary patterns derived from Reduced Rank Regression (RRR) analysis among Tehranian adults in a cohort study. Materials and Methods: Over a duration of 6 years, 141 adults were examined before and after 6 years for obesity indices. Dietary intakes were recorded at baseline by two 24 hour dietary recalls. RRR analysis derived five patterns with respect to total fat, polyunsaturated-to-saturated fat ratio, cholesterol, fiber and calcium intakes. The calculated factor scores were categorized in quintiles and changes in obesity indices were scrutinized within these quintiles. Results: The first pattern (traditional) showed high loadings on refined carbohydrates, whole grain, vegetables, red and processed meat, saturated and trans fat, egg, showing significant high positive correlation with fat, cholesterol and calcium intakes (r=0.478, 0.626, and 0.486, respectively; p<0.001). All obesity indices had an increasing trend across quintiles of pattern score (p<0.05 for BMI and WHR, p<0.001 for WC). The fifth pattern (egg) had high loading for eggs, salty snacks, and fruits, and negative loadings for red and processed meat, saturated and trans fat, plant oil, and dairy products, indicating increasing trends for WC (p<0.001) and WHR (p<0.05) after adjustment for potential confounders. Other patterns showed non-significant trends for obesity indices. Conclusion: RRR analyses were indicative of two dominant dietary patterns correlated with increase in obesity indices in Tehran

Dietary patterns by reduced rank regression predicting changes in obesity indices in a cohort study: Tehran Lipid and Glucose Study

Objective: To examine the association between dietary patterns and obesity indices (BMI, WC, WHR) among Tehranian adults in a 6-year follow-up study. Methods: Within frame of a cohort study in Tehran (mean follow up 6.6±0.9 years), 141 adults were recruited with: two 24 hour dietary recalls at the beginning, as well as obesity indices at the beginning and end of the study period. Dietary intakes were converted into grams of intakes of food items and categorized into 16 groups. Reduced rank regression analysis derived five patterns with total and polyunsaturated-to-saturated fat intake, cholesterol, fiber and calcium intake as response variables. Factors (dietary patterns) were generated retaining a corresponding factor loading � |0.17| on the food groups. Changes in obesity indices were scrutinized within quintiles of factor scores. Results: There were high loadings on refined carbohydrates, whole grain, starchy vegetables, other vegetables, red and refined meat, saturated/trans fat, and egg for the first factor named "traditional". All obesity indices had increasing trend across quintiles of pattern score. The fifth pattern (namely egg pattern) had high loading for eggs, salty snacks, as well as fruits and dry fruits, and negative loadings for red and processed meat, saturated and trans fat, plant oils, and dairy products. This pattern showed increasing trends for WC and WHR after adjustment for potential confounders. Other patterns showed non-significant trends for obesity indices. Conclusions: The results were indicative of a traditional pattern which is dominated in the Tehran region and associated with increase in obesity indices