Mark K Su1,2, Pui Ying Chan3, Robert S Hoffman2. 1. New York City Poison Control Center, New York, NY, USA. 2. Division of Medical Toxicology, Ronald O. Perelman Department of Emergency Medicine, NYU School of Medicine, New York, NY, USA. 3. Bureau of Epidemiology, New York City Department of Health and Mental Hygiene, New York, NY, USA.
Abstract
Introduction: Suicide attempts by poisoning are increasing and suicide occurrence may be associated with seasonality. We performed a retrospective analysis of poisoning exposure data from a single Poison Control Center (PCC) to determine if suicide attempts were associated with season, day of the week, and/or US holidays. Methods: We analyzed exposure cases identified as "intentional overdose - suspected suicide attempt" over 2009-2012. We used singular spectrum analysis (SSA) to detect cyclic patterns in the data and then performed Poisson regression and t-tests to determine if the number of cases were associated with season, day of the week, and US holidays. Results: There were 42,578 cases of "intentional overdose - suspected suicide" during the study period. Singular Spectrum Analysis (SSA) showed that the number of cases associated with poisoning suicide attempts peaked in the Spring and dipped in the Fall. Regression analysis showed higher numbers of suspected suicide attempts from intentional overdose in spring compared with winter by 1.07 times (p = 0.003), and on Sunday (p < 0.001), Monday (p < 0.001), and Thursday (p = 0.02) compared with Saturday by at least 1.09 times. No significant difference was seen for most holidays except for lower numbers of cases around Christmas (3 days before and after; 22.0 vs. 32.3 on control dates, p < 0.001).Conclusions: Suicide attempts by poisoning are associated with season of the year and some days of the week. Further research is required determine reasons for these associations and implementation of public health interventions.
Introduction: Suicide attempts by poisoning are increasing and suicide occurrence may be associated with seasonality. We performed a retrospective analysis of poisoning exposure data from a single Poison Control Center (PCC) to determine if suicide attempts were associated with season, day of the week, and/or US holidays. Methods: We analyzed exposure cases identified as "intentional overdose - suspected suicide attempt" over 2009-2012. We used singular spectrum analysis (SSA) to detect cyclic patterns in the data and then performed Poisson regression and t-tests to determine if the number of cases were associated with season, day of the week, and US holidays. Results: There were 42,578 cases of "intentional overdose - suspected suicide" during the study period. Singular Spectrum Analysis (SSA) showed that the number of cases associated with poisoning suicide attempts peaked in the Spring and dipped in the Fall. Regression analysis showed higher numbers of suspected suicide attempts from intentional overdose in spring compared with winter by 1.07 times (p = 0.003), and on Sunday (p < 0.001), Monday (p < 0.001), and Thursday (p = 0.02) compared with Saturday by at least 1.09 times. No significant difference was seen for most holidays except for lower numbers of cases around Christmas (3 days before and after; 22.0 vs. 32.3 on control dates, p < 0.001).Conclusions: Suicide attempts by poisoning are associated with season of the year and some days of the week. Further research is required determine reasons for these associations and implementation of public health interventions.
Entities:
Keywords:
Poison Control Center; Suicide; overdose; seasonality