The association between nervous system drugs and incidence of Amyotrophic Lateral Sclerosis

No study, to our knowledge, has examined the relationship between prescription of drugs for the nervous system and subsequent onset of amyotrophic lateral sclerosis (ALS). Therefore, the objective of the present study was to assess this relationship in a large Italian population. The study population included all subjects identified at the 2001 Italian census, resident in Turin since 1996 (n=737,979). Census data were record-linked to the regional archive of drug prescriptions (active since 1997), and to the ALS Piedmont Registry (active since 1995). In the present study, only new ALS cases diagnosed from 2002 to 2014 were considered. Baseline demographic information was drawn from 2001 census data. Exposure to nervous system drugs (ATC code “N”) was measured from 1997 to 2012, or until 1 year before ALS onset. Subjects with at least 5 prescriptions of drugs belonging to the same ATC family were considered ever exposed to a certain family of drugs; in a further analysis the association with cumulative number of prescriptions of each drug family was examined. The association between exposure to nervous system drugs and ALS incidence was evaluated through Poisson multivariate regression models adjusted for sex, age, education and marital status. During the follow-up, 296 subjects in the cohort developed ALS. The risk of ALS was significantly reduced by exposure to analgesics (IRR=0.32; 95% CI=0.19-0.54) and psychoanaleptics (IRR=0.60; 95% CI=0.39-0.94), deriving in particular from exposure to the sub-families of opioids (IRR=0.12; 95% CI=0.05-0.29) and antidepressants (IRR=0.59; 95% CI=0.37-0.91), respectively. Regarding cumulative dose of drug prescriptions, a significantly decreased risk was found only for opioids (IRR=0.94; 95% CI=0.91-0.97, for a 1-prescription increase). In conclusion, the study revealed a significant protective role of opioids and antidepressants drugs in developing ALS disease.