Validation and reproducibility of a food frequency questionnaire to assess energy and fat intake in affluent north Indians D Pandey, V Bhatia, R Boddula, HK Singh and E Bhatia Department of Endocrinology, Sanjay Gandhi Post-Graduate Institute of Medical sciences, Lucknow.

Introduction Increasing prevalence India Change in food habits Obesity Type II diabetes mellitus Hypertension Cardiovascular disease Increased intake Energy Fat (especially saturated fat) Cholesterol Food frequency questionnaires (FFQ): A simple method of diet assessment for use in epidemiological studies. There are very few validated FFQ in India.

Aim Develop and validate a Food Frequency Questionnaire (FFQ) as a simple and reproducible epidemiological tool for assessing energy and fat intake in affluent population in north India.

Methods:Subjects FFQ validation study Urban high income group population Consecutive subjects: first 30 volunteers over 3 weeks n = 30, 16 males, 14 females; mean ages 47.9 + 13.6 years Diet record (DR) and FFQ (n =30) Reproducibility study re-administered< 3 m FFQ II (n = 23)

Methods 1 + Diet record: 5 non-consecutive days: 1-2 weekend and remaining weekdays. Major festivals and brief illnesses excluded. In terms of standardized cups, spoons, 3 D food models, definite weight and /or brand. Food eaten at home Food eaten outside +

Methods 2 Semi-quantitative food frequency questionnaire: Designed to assess energy, total and saturated fat cholesterol and cholesterol-saturated fat index (CSI)# Interviewer administered (> 20 minutes). Food list: 102 food items divided into 10 groups. Portion size: Standardized cups and spoons, definite brand and/or weight and 3 D food models. Frequency: Open ended, reference period 1 year. # CSI = 1.01 X saturated fat (gm) + 0.05 X cholesterol (mg) Connor et al.1986

Data (log transformed) Statistical Analysis Data (log transformed) Mean + S.D Paired t-test Adjusted for calories by regression analysis Pearson’s correlation Regression coefficient Quartile categorization

Paired t-test: Only total fat significantly different (p<0.05) Results:Validation Mean values of DR and FFQ and percentage overestimation by FFQ Nutrient DR FFQ % over-estimation Energy (Kcal) 1726 1838 6 Total fat (gm) 42.6 50.5 17 Saturated fat (gm) 12.4 14.4 16 Cholesterol (mg) 91.5 104.5 14 CSI 17.0 19.9 Paired t-test: Only total fat significantly different (p<0.05)

DR vs. FFQ: Pearson’s correlation (r) and Regression coefficient (b) Results: Validation DR vs. FFQ: Pearson’s correlation (r) and Regression coefficient (b) Nutrient r (crude) r (adjusted) b Energy (Kcal) 0.80† - Total fat (gm) 0.55‡ 0.45 0.42 Saturated fat (gm) 0.63† 0.66† 0.85 Cholesterol (mg) 0.69† 0.64† 0.64 CSI 0.68† 0.90 † p < 0.01 ‡ p < 0.05

Results:Validation DR vs. FFQ: Quartile Categorization for Energy and energy adjusted nutrients

Results: Reproducibility Mean, Energy adjusted:Pearson’s correlation(r) and Regression coefficient (b) Nutrient FFQ FFQ II r b Energy (Kcal) 1838 1912 - Total fat (gm) 50.5 55.4 0.49 0.42 Saturated fat (gm) 14.4 14.7 0.66‡ 0.59 Cholesterol (mg) 104.5 100.1 0.86† 0.85 CSI 19.9 20.1 0.77† 0.65 † p < 0.005 ‡p = 0.05

Conclusions Diet record vs. FFQ: Validation Correlations: Moderate for fat and good for all other nutrients. Quartiles: Mostly good agreement. FFQ vs. FFQ II: Reproducibility Correlations: Moderate to strong correlations. The FFQ developed for an affluent north Indian population was easy to administer, showed moderate to good correlation with the diet record and was reproducible.