摘要：Objectives. We explored age, gender, and racial/ethnic differences with alcohol use and firearms, hanging or asphyxiation, and poisoning methods of suicide. Methods. We analyzed data for 37 993 suicide decedents aged 18 years and older from the 2005–2010 National Violent Death Reporting System database. Multinomial logistic regressions examined associations of method with alcohol use defined by blood alcohol content. Two-way interactions tested the effects of age, gender, and race/ethnicity on the associations between alcohol use and method of suicide. Results. Alcohol was present among decedents who used the 3 leading methods of suicide: firearm (35.0%), hanging (36.8%), and poisoning (32.7%). Two-way interaction tests suggested that in young and middle adulthood, individuals were more likely to drink alcohol when they used a firearm or hanging (compared with poisoning), but in older adulthood, the reverse was true, with alcohol use more likely with poisoning. Interaction tests also suggested that Asians and Pacific Islanders were most likely to use alcohol in poisonings and that Blacks were least likely to use alcohol in hangings. Conclusions. The results suggested that alcohol use before suicide was influenced by several factors, including age, race/ethnicity, and suicide method. Suicide is the 10th leading cause of death in the United States. 1 Suicide is among the leading types of injury mortality linked with alcohol consumption. 2 Most investigations of the alcohol-suicide relationship have examined the role of long-term patterns of alcohol use and related problems, including population studies of alcohol consumption or availability and suicide rates 3–5 and individual-level studies of the risk for suicide associated with alcohol use disorder. 6–8 There are more limited data on acute use of alcohol before suicide, although available data indicate that it plays a significant role. A meta-analysis of descriptive reports concluded that a median of 37% of suicides were preceded by acute use of alcohol. 9 The lone study of acute alcohol use and suicide that included a nonsuicide control group examined firearm suicides in a northeastern urban area of the United States. 10 The study revealed that acute drinking conferred risk after adjusting for alcohol availability and other factors, and that the degree of risk was increased with the amount of alcohol consumed, consistent with a dose-response relationship. Studies of nonlethal suicide attempts that used a nonsuicide attempt control group and adjusted for ongoing alcohol consumption pattern or alcohol use disorder also showed that acute alcohol use conferred risk and suggested a dose-response relationship. 11,12 A study of suicide attempters using a case-crossover design in which participants served as their own controls provided similar results. 13 Overall, available data from controlled studies of suicide and suicide attempts indicated that both the presence of alcohol and the amount of alcohol consumed were key considerations in understanding their link with suicidal behavior. 10–13 These controlled studies were of fairly small samples, making them poorly suited to examine age, gender, or racial/ethnic differences in the relationship between drinking and suicidal behavior. Several postmortem studies of suicide sought to determine if there were gender or age differences in the presence of acute alcohol use, with results generally showing that women and older adults were less likely to drink before suicide compared with men and other age groups. 9,14–16 There were fewer data on racial/ethnic differences in acute alcohol use before suicide, although a recent analysis of the US National Violent Death Reporting System (NVDRS) data highlighted that American Indians and Alaskan Natives (men and women) and Hispanic men were more likely than White men to be intoxicated at the time of death. 15 Differences in acute drinking before suicide in gender, age, and ethnic groups may reflect population patterns in drinking; for example, men generally drink more often and more heavily than women, 17 a pattern that is observed at the time of suicide. 14,15 However, studies of acute alcohol and suicide do not always reflect population patterns. For example, an analysis of NVDRS data that examined suicides with blood alcohol content (BAC) of 0.08 grams per deciliter or greater, the legal limit for drinking and driving in United States, showed that men aged 25 to 34, 35 to 44, and 45 to 54 years were more likely to have BAC 0.08 grams per deciliter or greater at the time of suicide than those aged 18 to 24 years. 15 The results were not explained by epidemiological patterns of drinking, because men aged 18 to 24 years in the United States have the highest frequency of intensive drinking. 17 Such findings indicate that it cannot be taken for granted that patterns of drinking before suicide reflect general population patterns. In the United States, 3 methods of suicide predominate; these are firearms, hanging or asphyxiation, and poisoning, which account for 90% of all suicides. 15 Somewhat different populations carry out these methods; for example, men are overrepresented in firearm suicides and women in poisonings. 15,18 The extent to which acute use of alcohol may differ across methods is unclear. In a national study in Finland, 19 the presence of acute alcohol use was more likely among suicides by poisoning (45.8%) and firearms (46.0%) compared with hanging (36.6%). However, the group differences became nonsignificant in multivariate analyses, underscoring the importance of adjustment for confounding. A national study of US suicides found that a BAC of 0.08 grams per deciliter or greater was associated with suicide by firearms among men. 20 A limitation was that the researchers examined BAC at or above a specific level, ruling out analyses of alcohol concentration across the continuum. In a previous analysis of NVDRS data, men and women were more likely to have BAC of 0.08 grams per deciliter or greater when they died by hanging or firearm compared with poisoning. 15 The results suggested that heavy use of alcohol was less involved in poisoning suicides compared with other leading methods. However, more refined analyses are needed, including tests of effect modification associated with gender, age, and race/ethnicity as well as consideration of the full range of BACs. The purpose of the present study was to conduct a detailed analysis of acute use of alcohol and the 3 leading methods of suicide using NVDRS data and to explore age, gender, and racial/ethnic differences in the use of alcohol before suicide and the dosage of alcohol. Results could provide a more complete understanding of acute alcohol use in suicide, including insights into which demographic groups are most likely to carry out lethal acts of suicide while drinking, at what concentration of alcohol, and using which method. The central premise of the study was that blanket conclusions about drinking in the event before suicide (for example, the finding of a review that a median of 37% of suicides had used alcohol 9 ) were likely to miss age, gender, and racial/ethnic differences, and that such differences might vary by method of suicide. There is growing evidence that public policies aimed at reducing alcohol consumption and availability might reduce rates of suicide. 21–23 Accordingly, the present study might suggest which groups could benefit most from such policies from the standpoint of suicide prevention.
