Elderly-onset essential tremor is associated with dementia.

OBJECTIVE: To determine whether essential tremor (ET) is associated with prevalent dementia.

METHODS: The authors identified all persons with dementia and ET in a population-based study in central Spain (the Neurological Disorders in Central Spain [NEDICES] Study). Dementia was diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) criteria.

RESULTS: Thirty-one (11.4%) of 273 ET cases had dementia vs 204 (6.0%) of 3,382 non-ET subjects (controls) (odds ratio [OR] = 2.00, 95% CI = 1.34 to 2.98, p = 0.001). In a model that adjusted for age, stroke, and educational level, OR = 1.35, 95% CI = 0.87 to 2.18, and p = 0.17. In an adjusted model, ET cases with tremor onset after age 65 were 70% more likely to be demented than were controls (OR = 1.70, 95% CI = 1.04 to 2.76, p = 0.03), whereas ET cases with tremor onset at age < or = 65 and controls were equally likely to be demented (OR = 0.38, 95% CI = 0.09 to 1.73, p = 0.21).

CONCLUSIONS: Older-onset essential tremor (ET) was associated with dementia. Prospective studies are required to elucidate the association between ET and dementia.