Control group. The control subjects were defined
as those with no record of a claim for a dementia
diagnosis during the years 2000–2009. For each
case, up to six control subjects without a dementia
diagnosis during the study period were randomly
matched for gender and age. If there were < 6 eligible
subjects, they were all were included. Each
comparison subject was assigned the same index
date as that of the matched cases. As a result, the
study population consisted of 9,304 subjects with
dementia and 55,500 matched controls in our subsequent
analysis (Fig. 1).