Determinants and detection of low body mass index in community-dwelling adults with Alzheimer's disease

Objective: To determine the proportion of older adults with Alzheimer's dis ease presenting to a geriatric clinic with low body mass index (BMI), the p roportion of these individuals recognized by clinicians as malnourished, an d what patients' characteristics and caregivers' and clinicians' impression s are associated with low BMI. Design: Cross-sectional study. Setting: An o utpatient geriatric clinic located in a university-affiliated teaching hosp ital. Participants: 340 patients with Alzheimer's disease, average age 75 y ears. Measurements: Individuals with a BMI below 21 were considered at risk of malnutrition. Physical examination and medical information were obtaine d from patients and caregivers by clinicians using a standardized assessmen t protocol. Clinicians' impression regarding evidence of malnutrition was o btained. Results: Forty-six patients (16%) had a BMI below 21. Clinicians r eported evidence of potential malnutrition in 11 patients, 8 of whom had a BMI below 21. Using logistic regression, we found that women were five time s more Likely to have a BMI below 21 than men, and that individuals with lo w cognition were twice as likely to have a BMI below 21 than individuals wi th higher cognition. Conclusion: The proportion of patients with Alzheimer' s disease with a BMI below 21 is similar to that encountered in the general population aged 65+. However, clinicians have difficulty identifying perso ns at risk of malnutrition according to BMI status. Women with low cognitio n were at increased risk of having a low BMI. Improvement in the detection of malnutrition is desirable. Further exploration of causal Links between c ognition and malnutrition is required.