Cobalamin Intake in North Indians by Food Frequency Questionnaire (COIN-FFQ) - A Development and Validation Study.

Background: Vitamin B₁₂ deficiency is widely prevalent in all age groups which is of major concern. However, there is no valid Food Frequency Questionnaire (FFQ) for dietary vitamin B₁₂ estimation. Hence, we aimed to develop and validate an FFQ for the estimation of dietary intake of Vitamin B₁₂.

Materials and methods: Commonly consumed B₁₂-rich food items were selected from literature and filtered using a market survey. For concordant and discriminant validation, B₁₂ and homocysteine levels were estimated. To establish convergent validity, the Cobalamin Intake in North Indians by Food Frequency Questionnaire (COIN-FFQ) and 72-hour dietary recall (72HrDR) were both administered to the same subjects. The COIN-FFQ was readministered after initial administration for test-retest reliability. Internal consistency of the FFQ was then tested using Cronbach's alpha.

Results: We enrolled 115 adults with a mean age and weight of 31.9 ± 8.7 years and 66.0 ± 11.8 kg, respectively. In total, 19.1% were vegetarian. The dietary B₁₂ using COIN-FFQ (n = 60; mean = 4.3 ± 1.8 µg/d) was significantly correlated (r = 0.255; P = 0.049) with serum levels (mean = 120.1 ± 62.6 pmol/L) establishing concordant validity. A significant difference was noted between the dietary, serum B₁₂, and homocysteine levels of vegetarians versus nonvegetarians establishing discriminant validity (mean diff 1.4 (0.5-2.4), P = 0.004; Z-statistic -2.182, P value 0.029, and Z-statistic -2.438; P value 0.015), respectively. FFQ was strongly correlated with 72HrDR and test-retest FFQ (n = 27; r = 0.814, P < 0.001 and r = 0.869, P < 0.001, respectively) establishing convergent validity and test-retest reliability. The internal consistency with Cronbach's alpha was in the acceptable range, 0.631 (n = 115).

Conclusion: The newly developed COIN-FFQ is valid and reliable in estimating dietary B₁₂ intake.