BMI, functional and cognitive status in a cohort of nonagenarians: results from the Mugello study

Our aim was to investigate the association of body mass index (BMI) with functional and cognitive status in a group of nonagenarians. By grouping the participants according to BMI categories, overweight and obese participants showed lower functional capability, higher risk of falling but better Mini-Mental State Examination (MMSE) performance than participants with normal weight or underweight. This cross-sectional survey supports the hypothesis that adiposity could affect the cognitive state of people reaching the old age. The study of the relationship between body weight and health in old age has attracted increasing interest. The aim of the present study is to investigate the association of body mass index (BMI) with functional and cognitive status in a group of nonagenarians. We analyzed 475 participants (348 women, 127 men; median age 92 years) from the Mugello study. Participants were evaluated through laboratory, instrumental examinations and questionnaires. By grouping the participants according to BMI categories, a better perception of health and nutritional status and a lower prevalence of sarcopenia (p < 0.05) were observed in participants with overweight and obesity compared to participants with normal weight or underweight. Concerning functional and cognitive measures, overweight and obese participants showed significantly worse performance on short physical performance battery and timed up and go tests and better performance on the mini-mental state examination (MMSE). As regards the other tests performed, no statistically significant differences were observed. In a multivariate logistic regression analysis adjusted for possible confounding factors, participants with BMI ≥ 30 kg/m2 showed lower probability to achieve poor performance on the MMSE (OR 0.42; 95% CI 0.19–0.94; p = 0.035). Our results support the hypothesis that in nonagenarians, a higher BMI is associated with better cognitive ability. Further studies are needed to explore the mechanisms underlying this association.