Obesity, abdominal obesity and Alzheimer disease

Obesity has a strong association with vascular and metabolic diseases, which have been linked with Alzheimer disease (AD). While recent studies have reported an association between mid-life obesity and dementia, the role of later-life obesity is less clear. This study investigated the relation between AD, obesity and abdominal obesity at later-life in a case-control study.

Participants were 50 consecutive patients with probable AD from memory disorders clinics in Launceston, Australia, and Bristol, England, and 75 cognitively normal controls. Height and weight [from which body mass index (BMI) was calculated] and hip and waist circumferences (from which waist-hip ratio was calculated) were measured. Participants were classified according to their BMI as: underweight (BMI <20.0 kg/m2); normal weight (BMI 20.0-24.9 kg/m2); overweight (BMI 25-29.9 kg/m2), or obese (BMI > or = 30 kg/m2). They were classified as abdominally obese if their waist-hip ratio was >0.9 (men) or >0.8 (women).

AD was associated with obesity [OR 9.5, 95% CI 2.4-37.3, p = 0.001], underweight (OR 5.4, CI 0.9-33.7, p = 0.07) and abdominal obesity (OR 2.5, CI 1.1-5.7, p = 0.027) using logistic regression analyses adjusted for age, sex and location. The inclusion of metabolic risk factors in the model increased the ORs for obesity (OR 12.6, CI 2.8-56.5, p = 0.001) and underweight (OR 7.9, CI 1.0-66.3, p = 0.056).

AD may be associated with obesity, underweight and abdominal obesity at later life. Larger prospective studies are required to investigate this further.