Comments on 'Association Between Body Mass Index and Cognitive Function Among Older Adults in India: Findings from a Cross-Sectional Study'

We have read your article titled "Association Between Body Mass Index and Cognitive Function Among Older Adults in India: Findings from a Cross-Sectional Study" with great interest. In this study, the authors hypothesized that older individuals with higher body mass index (BMI) have beter cognitive functions. However, we have noticed some major problems in the study's designand interpretation. The study categorized patients' BMIs using the World Health Organization's definition as <18.5, 18.5-24.9, 25.0-29.9, and ≥30.0 kg/m2, which were referred to as under weight (UW), normal weight (NW), overweight (OW), and obese. While these reference values are generally accepted in the young adult population, the optimal BMI values for mortality and malnutrition are reported differently in older adults. The suggested cut off values in nutritional assessment scales are higher than ≥20.0 kg/m2 (e.g, normal values in MNA are>23 kg/m2, in MUST score>20 kg/m2, or in NRS-2002 >20.5 kg/m2). Additionally, in a large-scale meta-analysis, it was reported that the geriatric population had the lowest mortality rate between a BMI of 23-30 kg/m2.