Results
The mean age of persons with PD and their controls were 73.5 years and
73.6 years, respectively (range 44.4–95.8), and majority of them were
men (table 1). Median duration of diabetes on index date was 8.8 years
in persons with PD and 8.5 years in persons without PD. There were no
differences in comorbidities, except for history of traumatic brain
injury which was more prevalent among PD cases compared to controls.
Statin users were more likely to be men (61.9% of users and 38.1% of
nonusers) (table 2). All comorbidities, except cancer and rheumatoid
arthritis, were more common among statin users, with largest difference
observed in cardiovascular diseases (71.9% of users and 59.7% of
nonusers).
Prevalence of any statin exposure before or only during the three-year
lag was similar among persons with PD and without PD (54.2% vs. 54.4%
and 10.9% vs. 10.6%) (table 3). Simvastatin was the most commonly used
statin, with 38.8% of cases and 40.1% controls exposed before the
three-year lag. There was no difference in use of specific statins
between PD cases and controls (table 3). Use of hydrophilic statins was
not common before the three-year lag (n=901), and majority of their
users had also purchased lipophilic statins (78.0%, n=703). There was
no difference in prevalence of lipophilic or hydrophilic statin use
between cases and controls.
Any statin use before the three-year lag was not associated with the
risk of PD (adjusted odds ratio (aOR) = 1.02; 95% CI: 0.91–1.15)
(table 4). In the dose-response analyses, an increased risk of PD was
observed in the highest statin exposure tertile compared to statin
non-use (aOR = 1.21; 95% CI: 1.04–1.42). Similarly, in the secondary
analysis restricted to statin users only, an increased risk of PD was
observed in the highest exposure tertile compared to the lowest exposure
tertile (aOR = 1.29; 95% CI: 1.07–1.57).