Methodological considerations of diet assessment of the older Indian population in the longitudinal aging study in India-Harmonised Diagnostic Assessment of Dementia (LASI-DAD).

INTRODUCTION: It is predicted that low-and- middle-income countries like India will bear the maximum brunt of global aging in the near future. Aging societies are increasingly facing higher incidence of cognitive decline and dementia. Research on the potential of dietary patterns as a modifiable lifestyle factor for protection of cognitive health has gained momentum. This study aims at developing a dietary assessment tool-food frequency questionnaire (FFQ) for older Indian adults in the community. METHODOLOGY: An FFQ was developed for the diverse, older population in India to collect data on their food intake over the past 12 months. This was pre and pilot tested leveraging the sample of an ongoing longitudinal study of late life cognition in older adults in India - Longitudinal Aging Study in India- Harmonized Diagnostic Assessment of Dementia (LASI-DAD). The FFQ was pilot tested during the first wave of the study (2017-2020) on a sample of 1125 respondents, updated and modified and finally implemented in the second wave of the study on 4465 respondents (2022-2024). An electronic Computer Assisted personal interview (CAPI) system with the use of tablets was implemented. The LASI-DAD FFQ was translated to 12 Indian languages for collecting accurate data from different regions of the country. A diverse range of food products and list of local food from different parts of India were included. RESULTS: The challenges faced, lessons learnt and modifications helped shape the final LASI-DAD FFQ. This was implemented in 24 Indian states. It had 4 sections: (A) Food consumption habits (B) Food frequency section (C) Herbal /non herbal/ayurvedic supplements (D) Spice intake. The final questionnaire had 88 food items and median time taken to complete was 31 min. Response rate varied from 97 to 100%. CONCLUSION AND DISCUSSION: The LASI-DAD FFQ proved to be a good tool for dietary data collection from a diverse, older Indian population. It is a single, comprehensive questionnaire adapted to the diverse dietary habits of older Indian population factoring in socio-economic, geographic, cultural, religious and seasonal variations, and it will help explore potential associations between diet and late-life cognition in older Indians.