Seasonal variation in fatal and non-fatal drug overdoses among young people

Abstract Background There has been an increasing trend in drug-induced deaths. In Finland, especially deaths of young people have increased during the recent years causing high amounts of years of life lost. More understanding is needed of these unfortunate yet preventable incidences. The aim was to study seasonal patterns in drug-induced deaths as well as non-fatal drug overdoses from five points of view, i.e. variation by season, by month, by time-of-month (cf. common payday on month's first day), weekday and public holidays. Methods A linked register data (Pathways to Early Death, PAD) drawn from several Finnish registers was used. Data include a follow-up data of all young people (aged <30) who had died or nearly died due to drug overdose during 2019-2021. Daily count of drug-induced deaths (n = 310) and non-fatal overdoses (n = 3725) was used to study seasonal variation. Results The preliminary results show that seasonal variation in drug-induced deaths was modest. The risk for drug-induced death was increased in October (Observed deaths/Expected death (O/E) 1.59, 95% confidence interval 1.17-2.16) and during the first half of the month (O/E 1.19, 95% CI 1.03-1.38), whereas no statistically significant variation was found by season, weekday or public holiday. Preliminary results for non-fatal incidents showed slightly more seasonal variation. The risk for overdose was increased in summer (O/E 1.19, 95% CI 1.12-1.26) and decreased in winter (O/E 0.84, 0.78-0.90). Similarly, the risk was slightly higher in weekends (O/E 1.05, 95% CI 1.0-1.1) compared to workdays (O/E 0.96, 95% CI 0.92-1.0). Conclusions The modest seasonal variation in drug-induced deaths indicates that most deaths occur among young people for whom drug use is an integral part of everyday life. Although somewhat more clear patterns could be seen in non-fatal overdoses, the findings highlight the need for interventions throughout the year to prevent drug-induced fatalities among young people. Key messages • There was only a modest seasonal variation in drug-induced deaths, whereas somewhat more clear patterns were observed in non-fatal overdoses. • Interventions are needed throughout the year to prevent drug-related fatalities among young people.