Objective: To study the relationships between body mass index (BMI) and different domains of disability in elderly subjects from the French 3C study.
Setting: Three cities in France: Bordeaux (South-West), Dijon (North-East) and Montpellier (South-East).
Design: Cross-sectional study.
Subjects: A sample of 8966 elderly community dwellers (age: 65-101 y).
Main outcome measures: BMI, continence, basic and Instrumental Activities of Daily Living (ADL and IADL) and mobility. Adjustment variables: age, educational level, lifestyle, cognitive functioning, smoking and drinking history, depression, dyspnea, diabetes and indicator of cardiovascular disease.
Results: Obesity (BMI> or =30 kg/m2) was significantly associated with disability in each domain for women. The relationship tended to be linear for ADL and for continence; whereas for IADL, underweight women (BMI <21 kg/m2) were also at higher risk of disability. In men, relationships were weaker since BMI was only associated with mobility restriction, with a higher risk for both underweight and obese subjects.
Conclusion: These results are in favor of a strong association between obesity and the three domains of disability and incontinence. Weaker relationships between underweight and disability were observed. Results suggest that maintaining a BMI in the healthy range could contribute to independence in activities of daily living.