Association among Olfactory Function, Lifestyle and BMI in Female and Male Elderly Subjects: A Cross-Sectional Study

Physical activities seem to counteract the age-related physiological decline of the olfactory function which, influencing the food choices and eating behavior, can affect the body weight of individuals. The main purpose of this cross-sectional study was to evaluate the relationships between olfactory function and BMI in female and male Elderly Subjects (ES), according to the level of their lifestyle activities in physical, cognitive, and social terms. Considering weekly physical activities, the adult elderlies who decided to participate in this study were divided into active ES (n = 65) and non-active ES (n = 68). Assessment of weekly activities and olfactory function were performed by means of face-to-face interviews and the "Sniffin' Sticks" battery test, respectively. The results show that ES who are overweight and with a non-active lifestyle achieved lower TDI olfactory scores than normal weight ES and those classified as active. Hyposmic and non-active ES showed a higher BMI than normosmic and active ES. Sex-related differences, with females performing better than males, were evident in the presence of at least one of the following conditions: non-activity, hyposmia, or overweight. Inverse correlations were found between BMI and TDI olfactory score and between BMI and hours/week spent on physical activities, both when subjects were considered all together and when they were divided into females and males. These findings suggest that a higher BMI is related to the olfactory dysfunction linked to active or non-active lifestyle and the sex-related differences, and the condition of hyposmia is related to the increase in body weight due to lifestyle and sex differences. Given that the relationship between BMI and non-exercise physical activities is comparable to that between BMI and exercise physical activities, and this may be of particular importance for ES with limited mobility.