Body Mass Index and Its Relationship with Disability, Chronic Diseases and Frailty in Older People: A Comparison of the Lipschitz and Who Classifications.

BACKGROUND: Anthropometric parameters are closely associated with the pathophysiology of frailty and with clinic and functional parameters assessed for its diagnosis.

OBJECTIVE: To evaluate the possible association of the nutritional status of older people as assessed by Body Mass Index (BMI) and functional disability, self-reported chronic diseases and frailty, comparing the use of two different classifications of BMI.

DESIGN: Cross-sectional study.

SETTING: The sample was selected among community-dwelling older people from the city of Ribeirão Preto/ Brazil.

PARTICIPANTS: 326 independent older people (mean age 73.8±6.4 years) who participated in the FIBRA (Frailty in Brazilian Older People) study.

MEASUREMENTS: Weight and height were collected for BMI analysis and frailty criteria were applied according to Fried et al. Participants were also evaluated for self-reported activities of daily living (Katz Index and Lawton and Brody Scale), and the presence of chronic diseases.

RESULTS: The prevalence of frailty was 12.3%. Regardless of the classification of BMI applied, most of the sample was classified as overweight (50.9% and 39.3% in the Lipschitz and WHO classifications, respectively). For both classifications, low weight was the only BMI classification associated with frailty status (OR Lipschitz: 4.12(1.53-11.14); OR WHO: 6.21 (1.26-30.58). Comorbidities and dependence in activities of daily living (ADLs) were associated with BMI ≥ 30kg.m2.

CONCLUSION: Regardless of the classification adopted, low weight is associated with frailty. However, when the WHO stratification is employed, high BMI is also associated to increased functional disability and the presence of comorbidities, coexisting factors of frailty.