Medical and environmental risk factors for sporadic frontotemporal dementia: a retrospective case-control study.

A retrospective case-control study was carried out on 80 patients with sporadic frontotemporal dementia and 124 age, sex, and surrogate informant matched controls with respect to various medical and environmental risk factors. Head trauma was associated with an odds ratio of 3.3 (95% confidence interval (CI), 1.3 to 8.1). Although recall bias may play a role, the frontal lobes are known to be especially vulnerable to even mild head trauma. Thyroid disease was associated with a 2.5 times increased risk of frontotemporal dementia (95% CI, 0.9 to 7.9), which was not statistically significant (p = 0.09) owing to limited power. As altered thyroid hormone status has been observed before in frontotemporal dementia, future studies will be important to confirm this observation.