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.