AMBIENT-TEMPERATURE AND MORTALITY FROM UNINTENTIONAL COCAINE OVERDOSE

Context.-Hot weather taxes cardiovascular function and is associated w ith increased deaths from heart disease. Cocaine can cause hypertensio n, tachycardia, coronary vasospasm, arrhythmias, and increased core te mperature. Objective.-To determine the association between mortality f rom cocaine overdose and hot weather. Setting.-New York, NY. Design.-R etrospective review of medical examiner cases from 1990 through 1995.S ubjects.-All fatal unintentional cocaine overdoses from 1990 through 1 992 (n=1382) and all hyperthermia deaths of cocaine users (n = 10) wer e used to identify a maximum daily temperature threshold above which m ortality from cocaine intoxication increased. The study population con sisted of all fatal unintentional cocaine overdoses from 1993 through 1995 (n = 2008) and 4 contemporaneous comparison groups that included fatal unintentional opiate overdoses (n = 793), all other fatal uninte ntional overdoses (n = 85), and a subset of homicides (n = 4638) and f atalities from motor vehicle crashes (n = 815). Main Outcome Measures. -The number of overdose deaths and the proportion of homicides and tra ffic fatalities with a positive cocaine toxicology test result on days with a maximum temperature above or below the temperature threshold. Results.-A threshold temperature of 31.1 degrees C (88 degrees F) was identified, above which the mean daily number of fatal cocaine overdos es increased steadily. On days with a maximum daily temperature of 31. 1 degrees C (88 degrees F) or higher (''hot days''), the mean daily nu mber of cocaine overdose deaths was 2.34 (SD = 1.68), which was 33% hi gher than the mean on days with a maximum temperature of less than 31. 1 degrees C (88 degrees F) (mean=1.76 [SD=1.37] (P<.001). In contrast, the mean number of opiate overdose deaths per day was 0.81 (SD = 0.94 ) on hot days and 0.71 (SD = 0.86) on other days (P=.28). For other dr ug overdose deaths, the mean number of deaths per day was 0.08 (SD = 0 .28) on hot days and 0.08 (SD = 0.28) on other days (P=.69). Among hom icides, the proportion with a positive cocaine toxicology test result was 18.9% on hot days and 19.5% on other days (P=.69), and among traff ic fatalities, the proportions with positive cocaine toxicology test r esults were 9.5% on hot days and 10.3% on other days (P=.91). Conclusi ons.-High ambient temperature is associated with a significant increas e in mortality from cocaine overdose. Based on our comparison groups, the increase is not explained by changes in cocaine use among the gene ral population. Although cocaine use is dangerous on all days, it appe ars to be even more dangerous on hot days.