Development and evaluation of a semi-quantitative food frequency questionnaire for use in urban and rural India.

The objective of this study was to develop and evaluate a semi-quantitative food frequency questionnaire (FFQ) for use in urban and rural India. A single FFQ was developed for use in cities and rural areas of four regions of India. To assess validity, the FFQ was administered to 530 factory workers and rural dwellers, and subsequently three 24 hour recalls were administered on different days. Nutrient and food group intake calculated from these two methods were compared using medians, kappa statistics, Spearman's correlation coefficients and Bland-Altman plots. Dietary intake was overestimated by the FFQ compared to the 24 hour recalls (mean difference in energy intake = 1743 kJ), with kappa statistics ranging from 0.07 (egg) to 0.51 (carbohydrate). The results showed acceptable validity for measuring intakes of groups, and demonstrated that it is feasible to measure dietary intake in diverse regions of India with a single FFQ.