Dietary assessment
Trained dietitians obtained the usual food intake through a structured interview. A valid and reliable 147-item semi-quantitative FFQ with standard servings was applied to determine typical food intakes.37,38 The intake frequency of each food item was asked on a daily, weekly, or monthly basis during the past year and converted to the gram. Total energy and nutrient intake were then calculated using Nutritionist IV software (the Hearst Corporation, San Bruno, CA) as modified for Iranian foods.