Anthropometric indices predict physical function and mobility in older Australians: the Australian Longitudinal Study of Ageing.

OBJECTIVE: To evaluate, in terms of function and mobility, the predictive value of commonly adopted anthropometric 'definitions' used in the nutritional assessment of older adults, in a cohort of older Australians.

DESIGN: Prospective cohort study - Australian Longitudinal Study of Ageing (ALSA).

SETTING: Adelaide, South Australia (1992-1994).

SUBJECTS: Data were analysed from 1272 non-institutionalised (685 males, 587 females) older adults > or =70 years old in South Australia. Seven 'definitions' commonly used in the anthropometric assessment of both under- and overnutrition (including four using body mass index (BMI), waist-to-hip ratio, waist circumference and percentage weight change) were evaluated at baseline, for their ability to predict functional and mobility limitation assessed (by self-report questionnaire) at two years follow-up. All questionnaires were administered and anthropometry performed by trained investigators. The associations between the definitions and decline in mobility and physical function were evaluated over two years using multiple logistic regression.

RESULTS: A BMI >85th percentile or >30 kg m-2 or a waist circumference of >102 cm in males and >88 cm in females increased risk of functional and mobility limitations. Over two years, a loss of 10% body weight significantly increased the risk of functional and mobility limitations.

CONCLUSION: Maintaining weight within older adults, irrespective of initial body weight, may be important in preventing functional and mobility limitations. Excessive weight is associated with an increased risk of limitation in function and mobility, both key components of health-related quality of life.