Population-based case-control study of essential tremor.

Current epidemiologic data on the association between environmental factors and essential tremor (ET) are scanty. In a population-based case-control study we investigated the relationship between some putative risk factors and ET. In the present study, we included all subjects identified during a door-to-door prevalence survey in a Sicilian community, affected by ET, and alive on 1 November 1987 (n=31). Of the 31 prevalent cases of ET, we were able to contact 28 subjects. Twenty-eight controls were randomly selected from the general population and matched to each case for age and sex. Exposure variables were investigated by interviewing the patients and their controls or close relatives, using a structured questionnaire. The odds for habitual alcohol consumption were 0.3, indicating a protective effect. The odds for exposure to agricultural chemicals and domestic animals were 2.5 and 2.7, respectively, suggesting a role as potential risk factors. However, the associations found by us were not statistically significant.