DEVELOPMENT AND VALIDATION OF A CULTURE-SPECIFIC FOOD FREQUENCY QUESTIONNAIRE AMONG PULMONARY TUBERCULOSIS PATIENTS IN SABAH, MALAYSIA

Accurate dietary assessment among populations with infectious diseases remains a challenge, particularly in culturally diverse and low-resource settings. This study aimed to develop and validate a region-specific Food Frequency Questionnaire (FFQ) to assess nutrient intake among patients with pulmonary tuberculosis (PTB) in Kota Kinabalu, Sabah, Malaysia. A semi-quantitative FFQ comprising 62 food items grouped into 13 categories was developed based on three-day 24-hour dietary recalls (24HR) from 41 newly diagnosed adult PTB patients. The FFQ was validated by comparing nutrient intake estimates with the mean values obtained from 24-hour recalls using Pearson correlation, energy-adjusted correlation, cross-classification, and intra-class correlation coefficient (ICC) analysis. Reproducibility was assessed by administering the FFQ twice, with a three- to five-week interval between administrations. Unadjusted Pearson correlation coefficients between the FFQ and 24HR ranged from 0.39 (carotene) to 0.90 (energy), with a mean of 0.66 ± 0.17. Energy-adjusted correlations ranged from 0.23 (niacin) to 0.76 (vitamin B1), averaging 0.55 ± 0.16. The proportion of participants classified into the same nutrient intake quartile ranged from 27% to 61%, while the proportion of extreme misclassification ranged from 5% to 24%. ICCs for reproducibility between FFQ1 and FFQ2 were high, ranging from 0.79 (vitamin C) to 0.99 (protein). We validated an FFQ specifically designed for Malaysian patients with pulmonary tuberculosis, providing a culturally relevant and reproducible dietary assessment tool. The FFQ showed strong correlation with reference recalls (mean Pearson r = 0.66), and excellent reproducibility (ICC range 0.79–0.99). It is particularly suited for epidemiological research examining the association between nutrition and TB treatment outcomes, and can inform future nutritional surveillance and targeted interventions in TB control programs.