Statin adherence does not affect risk of Parkinson’s disease
Adherence to statin medications does not affect the risk of developing Parkinson’s disease (PD), reveals a new population-based cohort study.
The statin adherence patterns of a population of 232,877 individuals (49.3 percent male) were constructed from purchase data obtained from a large non-profit health maintenance organization and private pharmacies. Dosage, number of pills and purchase dates were recorded; a chronological record of adherence was constructed for each individual.
The cohort comprised individuals between 40 and 79 years of age at the date of first statin purchase. Annual plasma cholesterol profile measurements and the incidence of PD, as measured by antiparkinsonian drug (APD) purchases, were also recorded.
The mean age of males at first purchase of statins (56.5±9.8 years) was slightly lower compared to females (58.7±9.2 years). Follow-up period was 7.5±3.4 and 7.7±3.4 years for males and females, respectively. [PLoS One 2017;doi:10.1371/journal.pone.0175054]
There were 11,429,603 recorded statin purchases in the population over the duration of the study. Lipophilic statins were the most commonly prescribed type for both males (73.3 percent) and females (74 percent).
The median duration of adherence was 6.4 (3.3 to 9.0) and 6.5 (3.5 to 9.2) years for males and females, respectively. Adherence of males (52.9 percent) was slightly higher than of females (51 percent). Males with LDL-C levels ≤160 mg/dL were the most adherent group, while the youngest group in the population (40 to 55 years), regardless of and baseline LDL-C levels, were the least adherent.
There was a 1.1 percent (n=2,550; 1,195 females) incidence rate of PD among those that had at least 1 year of statin adherence. Age at first APD treatment was 72.2±8.1 and 72.4±7.7 for males and females, respectively. PD incidence was higher in males (1.2 percent) than in females (1.0 percent).
The investigators found no significant association between the risk of developing PD and annual statin adherence regardless of sex and age. For males and females with baseline LDL-C levels ≤160 mg/dL, the age-pooled hazard ratios [HR] were 0.99 (95 percent CI, 0.99 to 1.01) and 1.01 (1.00 to 1.02), respectively. For those with baseline levels of >160 mg/dL, the HRs were 0.99 (0.98 to 1.01) and 0.97 (0.98 to 1.01), respectively.
The results of the current study corroborate the findings of other large-scale epidemiological reports and meta-analyses, suggesting that there is “no evidence of a neuroprotective effect of statin adherence on PD in this large-scale cohort, considering refined assessments of statin exposure over-time as well as the information on LDL-C levels during the period of statin adherence,” the investigators said.
Taking theory and mechanism into consideration, the results of the current study are expected, they added. That is, while PD is more common in the elderly, its molecular pathology begins decades before the first cardinal motor manifestations are observed.
Thus, “any intervention aiming to slow down or prevent neurodegeneration should occur in the fourth or fifth decade of life rather than the sixth or seventh,” they continued.
While the current study was able to provide solid evidence that statins do not significantly affect the risk of developing PD, “[a]dditional large-scale observational studies employing long-term follow-up periods are needed to further elucidate this point,” the investigators concluded.