A 32-year prospective study of change in body weight and incident dementia: the Honolulu-Asia Aging Study.

BACKGROUND: The course of weight loss associated with dementia is unclear, particularly prior to and around the onset of the clinical syndrome.
OBJECTIVE: To compare the natural history of weight change from mid to late life in men with and without dementia in late life. DESIGN AND
SETTING: The Honolulu-Asia Aging Study, a 32-year, prospective, population-based study of Japanese American men who had been weighed on 6 occasions between 1965 and 1999 and who had been screened for dementia 3 times between 1991 and 1999. PARTICIPANTS: Of 1890 men (aged 77-98 years), 112 with incident dementia were compared with 1778 without dementia at the sixth examination (1997-1999). MAIN OUTCOME MEASURE: Weight change up to and including the sixth examination was treated as the dependent variable and estimated using a repeated measures analysis.
RESULTS: Groups with and without dementia did not differ with respect to baseline weight or change in weight from mid to late life (first 26 years' follow-up). In the late-life examinations (final 6 years), mean age- and education-adjusted weight loss was -0.22 kg/y (95% confidence intervals, -0.26 to -0.18) in participants without dementia. Men with incident dementia at the same examination had an additional yearly weight loss of -0.36 kg (95% confidence interval, -0.53 to -0.19). This was not changed substantially with adjustment for risk factors for vascular disease or functional impairment and was significant for both Alzheimer disease and vascular dementia subtypes.
CONCLUSIONS: Dementia-associated weight loss begins before the onset of the clinical syndrome and accelerates by the time of diagnosis. The potential impact on prognosis should be considered in the case of elderly persons at risk for dementia.