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State firearm laws and rates of suicide in men and women

  • Kenneth R Conner
    Correspondence
    Address correspondence and reprint requests to: Kenneth R. Conner, PsyD, MPH, Psychiatry, University of Rochester Medical Center, 300 Crittenden Blvd., Rochester NY 14642, USA.
    Affiliations
    University of Rochester Medical Center, Department of Psychiatry, Center for the Study and Prevention of Suicide, Rochester, New York, USA
    Search for articles by this author
  • Yueying Zhong
    Affiliations
    University of Rochester Medical Center, Department of Psychiatry, Center for the Study and Prevention of Suicide, Rochester, New York, USA
    Search for articles by this author

      Abstract

      Background

      To evaluate the associations of state laws restricting firearms and incidence rates of suicide in men and women using a cross-sectional design.

      Methods

      States were divided into three categories based on the restrictiveness of their firearm laws: restrictive (n =8); modest (n =22); and unrestrictive (n =20). State suicide incidence rates stratified by gender were compared using Poisson regression analyses that controlled for measures of race/ethnicity, income, and urbanization. Analyses were based on 2000 census data and state suicide data from 1999 and 2000.

      Results

      In the analysis of women, compared to states with restrictive firearm laws, there were higher suicide incidence rate ratios (IRR) in states with modest (IRR=1.64; 95% confidence interval [CI], 1.34–2.01) and unrestrictive laws (IRR=1.55; 95% CI, 1.23–1.95). The analysis of men showed comparable results: modest firearm laws (IRR=1.51; 95% CI, 1.27–1.79); unrestrictive firearm laws (IRR=1.49; 95% CI, 1.23–1.82).

      Conclusions

      Results support the hypothesis that state restrictions on firearms have the potential to reduce the suicide rate. Findings do not support a hypothesis that greater firearm restrictions are associated with the substitution of alternative methods of suicide. Firearms appear to be a comparable exposure for suicide in men and women. Although men are more likely to use firearms in suicide than women, this difference may merely reflect more frequent gun ownership among men.

      Introduction

      I n the United States, suicide is the eleventh leading cause of death and the fifth leading cause of years of potential life lost before age 75.

      National Center for Injury Prevention and Control. Years of potential life lost reports, 1999–2000. WISQARS Years of potential life lost reports, 2002. Available at: http://webapp.cdc.gov/sasweb/ncipc/ypll10.html. Accessed November 1, 2002

      Approximately 57% of suicides in the United States are committed with a firearm.

      National Center for Injury Prevention and Control. Injury mortality reports, 1999–2000. WISQARS injury mortality reports, 1999 and Later. 2002. Available at: http://webapp.cdc.gov/sasweb/ncipc/mortrate10.html. Accessed November 1, 2002

      There is strong evidence based on studies using case–control,
      • Brent D.A.
      • Perper J.A.
      • Allman C.J.
      • Moritz G.M.
      • Wartella M.E.
      • Zelenak J.P.
      The presence and accessibility of firearms in the homes of adolescent suicides.
      ,
      • Conwell Y.
      • Duberstein P.R.
      • Conner K.R.
      • Eberly S.
      • Cox C.
      • Caine E.D.
      Access to firearms and risk for suicide in late life.
      ,
      • Bailey J.E.
      • Kellermann A.L.
      • Somes G.W.
      • Banton J.G.
      • Rivara F.P.
      • Rushforth N.P.
      Risk factors for violent death of women in the home.
      ,
      • Cummings P.
      • Koepsell T.D.
      • Grossman D.C.
      • Savarino J.
      • Thompson R.S.
      The association between the purchase of a handgun and homicide or suicide.
      ,
      • Kellerman A.L.
      • Rivara F.P.
      • Somes G.
      • et al.
      Suicide in the home in relation to gun ownership.
      retrospective cohort,
      • Wintemute G.J.
      • Parham C.A.
      • Beaumont J.J.
      • Wright M.
      • Drake C.
      Mortality among recent purchasers of handguns.
      and cross-sectional designs
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      that firearm ownership/availability is associated with suicide.
      The aforementioned data on gun ownership/availability suggest that laws restricting firearm availability will reduce the suicide rate. However, evidence for an association of firearm restrictions and suicide is comparatively weak. One approach has been to use quasi-experimental designs to determine if changes in firearm laws have an impact on the rate of suicide. The data are mixed, with studies alternatively demonstrating that the implementation of tougher firearm restrictions was associated with a lower overall suicide rate,
      • Carrington P.J.
      • Moyer S.
      Gun control and suicide in Ontario.
      ,
      • Loftin C.
      • McDowall D.
      • Wiersema B.
      • Talbert C.J.
      Effects of restrictive licensing of handguns on homicide and suicide in the District of Columbia.
      no change in the overall suicide rate,
      • Ludwig J.
      • Cook P.J.
      Homicide and suicide rates associated with implementation of the Brady Handgun Violence Prevention Act.
      or no change in the overall rate except in subpopulations (e.g., urban men
      • Cantor C.H.
      • Slater P.J.
      The impact of firearm control legislation on suicide in Queensland preliminary findings.
      ). Some studies suggest that alternative lethal methods for suicide are substituted when the accessibility of firearms is reduced through legislation.
      • Cantor C.H.
      • Slater P.J.
      The impact of firearm control legislation on suicide in Queensland preliminary findings.
      ,
      • Sloan J.H.
      • Rivara F.P.
      • Reay D.T.
      • Ferris J.A.
      • Kellerman A.L.
      Firearm regulations and rates of suicide a comparison of two metropolitan cities.
      Other studies have not supported the method-substitution hypothesis.
      • Carrington P.J.
      • Moyer S.
      Gun control and suicide in Ontario.
      ,
      • Loftin C.
      • McDowall D.
      • Wiersema B.
      • Talbert C.J.
      Effects of restrictive licensing of handguns on homicide and suicide in the District of Columbia.
      Cross-sectional studies in the states have demonstrated more consistently than quasi-experimental designs an association of more stringent firearm laws and lower suicide rates.
      • Boor M.
      • Bair J.H.
      Suicide rates, handgun control laws, and sociodemographic variables.
      ,
      • Lester D.
      • Murrell M.
      The preventive effect of strict gun control laws on suicide and homicide.
      ,
      • Medoff M.H.
      • Magaddino J.P.
      Suicides and firearm control laws.
      However, these studies used suicide rate data from 1985 or before, indicating the need for studies using more recent data given subsequent changes that may affect the association of state firearm laws and suicide. For example, the Brady Handgun Violence Prevention Act (Public Law 103-109) and the Violence Against Women Act (Public Law 103-322) carried federal mandates on firearm restrictions that necessitated implementation in many states whereas other states had similar, pre-existing laws already in effect. In addition, some data suggest that there has been an overall increase in handgun ownership in the United States.
      • Blendon R.J.
      • Young J.T.
      • Hemenway D.
      The American public and the gun control debate.
      Finally, suicide among adolescent and young adult males rose dramatically before plateauing.
      • Gould M.S.
      • Kramer R.A.
      Youth suicide prevention.
      Firearms increase suicide risk in this group especially.
      • Brent D.A.
      • Perper J.A.
      • Allman C.J.
      • Moritz G.M.
      • Wartella M.E.
      • Zelenak J.P.
      The presence and accessibility of firearms in the homes of adolescent suicides.
      ,
      • Kellerman A.L.
      • Rivara F.P.
      • Somes G.
      • et al.
      Suicide in the home in relation to gun ownership.
      ,
      • Wintemute G.J.
      • Parham C.A.
      • Beaumont J.J.
      • Wright M.
      • Drake C.
      Mortality among recent purchasers of handguns.
      ,
      • Sloan J.H.
      • Rivara F.P.
      • Reay D.T.
      • Ferris J.A.
      • Kellerman A.L.
      Firearm regulations and rates of suicide a comparison of two metropolitan cities.
      Although data on age-related effects of firearm legislation on suicide risk are limited,
      • Ludwig J.
      • Cook P.J.
      Homicide and suicide rates associated with implementation of the Brady Handgun Violence Prevention Act.
      ,
      • Cantor C.H.
      • Slater P.J.
      The impact of firearm control legislation on suicide in Queensland preliminary findings.
      studies of firearm ownership/availability have shown that adolescents and young adults,
      • Kellerman A.L.
      • Rivara F.P.
      • Somes G.
      • et al.
      Suicide in the home in relation to gun ownership.
      ,
      • Wintemute G.J.
      • Parham C.A.
      • Beaumont J.J.
      • Wright M.
      • Drake C.
      Mortality among recent purchasers of handguns.
      ,
      • Sloan J.H.
      • Rivara F.P.
      • Reay D.T.
      • Ferris J.A.
      • Kellerman A.L.
      Firearm regulations and rates of suicide a comparison of two metropolitan cities.
      and possibly older adults,
      • Conwell Y.
      • Duberstein P.R.
      • Conner K.R.
      • Eberly S.
      • Cox C.
      • Caine E.D.
      Access to firearms and risk for suicide in late life.
      ,

      Birckmayer JD. The role of alcohol and firearms in youth suicide and homicide in the United States. Dissertation Abstracts International 1999;60 (6-B):2636

      are especially vulnerable to suicide by firearms. Compared to age-related effects, data on gender and firearm risk are inconsistent. Studies of firearm laws have reported that lesser restrictions on the purchase of handguns are associated with higher rates of male (but not female) suicide rates
      • Cantor C.H.
      • Slater P.J.
      The impact of firearm control legislation on suicide in Queensland preliminary findings.
      ,
      • Medoff M.H.
      • Magaddino J.P.
      Suicides and firearm control laws.
      and firearm suicide rates.
      • Ludwig J.
      • Cook P.J.
      Homicide and suicide rates associated with implementation of the Brady Handgun Violence Prevention Act.
      Data on ownership/availability, however, are mixed. Whereas case–control studies have shown that firearm ownership/availability confers risk in men more than in women,
      • Conwell Y.
      • Duberstein P.R.
      • Conner K.R.
      • Eberly S.
      • Cox C.
      • Caine E.D.
      Access to firearms and risk for suicide in late life.
      ,
      • Kellerman A.L.
      • Rivara F.P.
      • Somes G.
      • et al.
      Suicide in the home in relation to gun ownership.
      ,

      Brent DA, Perper JA, Moritz G, Baugher M, Schweers J, Roth C. Firearms and adolescent suicide: a community case-control study. Am J Dis Children 1993;147:1066–71

      a large retrospective cohort investigation in California concluded that the purchase of a handgun increased the suicide rate in women more than in men,
      • Wintemute G.J.
      • Parham C.A.
      • Beaumont J.J.
      • Wright M.
      • Drake C.
      Mortality among recent purchasers of handguns.
      and a recent cross-sectional study of state and regional suicide rates showed that firearms are associated with comparable risk for suicide in men and women.
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      A recent, rigorous cross-sectional investigation of the U.S. states showed a strong association of greater firearm ownership and higher rates of suicide.
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      However, contemporary cross-sectional data on state firearm laws and rates of suicide are unavailable, and data on firearm restrictions may inform policy directly. Unlike reasonably consistent data that age moderates the association of firearm exposure and suicide, the data on gender, firearms, and suicide are equivocal. The purpose of this study was to analyze data on variability in firearm restrictions and suicide rates among states in the U.S. to evaluate two research questions: (1) to evaluate whether states with modest and unrestrictive firearm laws, compared to those with restrictive laws, have higher suicide incidence rates; and (2) to determine whether greater firearm availability may increase risk in men more so than in women, given data that men are more likely to own a firearm and to use a firearm in suicide.

      Methods

      Measures

      The independent variable of interest was a three-category measure of restrictiveness of state firearm laws. This categorization was derived based on a comparative survey of state firearms laws.

      Open Society Institute. Gun control in the United States: a comparative survey of state firearm laws. Open Society Institute's Center on Crime, Communities & Culture and the Funder's Collaborative for Gun Violence Prevention 2000, April 11, 2002. Available at: www.soros.org/crime/guncontrol.htm. Accessed November 1, 2002

      The survey assigned scores on the restrictiveness of state firearm laws based on licensing and registration, background checks, minimum age requirements for purchase, waiting periods, “one-gun-a-month” laws, “junk gun” laws, restrictions on assault weapons, safe storage requirements, industry protection from litigation, and prohibition or limitation on municipalities from enacting local gun laws. Based on the scores, survey authors identified states with unrestrictive firearm laws (n =20) and those with modest restrictions (n =22). The remaining states (n =8) were determined to have strong or moderate firearm laws, heretofore referred to as states with “restrictive” firearm laws. The three categories are presented in Table 1.
      Table 1State firearm restrictiveness
      RestrictiveModest restrictionsUnrestrictive
      CaliforniaColoradoNevadaAlabamaMaine
      ConnecticutDelawareOhioAlaskaMississippi
      HawaiiFloridaOregonArizonaMontana
      IllinoisIowaPennsylvaniaArkansasN. Dakota
      MarylandMichiganRhode IslandGeorgiaOklahoma
      MassachusettsMinnesotaS. CarolinaIdahoS. Dakota
      New JerseyMissouriTennesseeIndianaTexas
      New YorkN. CarolinaUtahKansasVermont
      N. HampshireVirginiaKentuckyW. Virginia
      N. MexicoWashingtonLouisianaWyoming
      NebraskaWisconsin
      The categorizations were based on a summation of individual items comprising the survey, with higher scores indicating greater state restrictions on firearms. For example, scores were assigned to items concerning minimum age requirements for handguns (<18 years [−1]; 18 to 20 years [0]; 21 years [+3]) and for rifles and shotguns (<18 years [−1]; 18 to 20 years [0]; 21 years [+2]). Overall scores ranged from a low of −10 (Maine) to a high of 76 (Massachusetts). Although the items comprising the survey were face valid, the validity of scores assigned to each item has not been established. Therefore, analyses in this study were based on the categories provided by the survey authors rather than on continuous scores, because the latter suggest greater precision than may be warranted.
      For this study, categorization validity was supported using two established measures of gun ownership: (1) survey data on gun ownership in 21 states
      • Powell K.E.
      • Jacklin B.C.
      • Nelson D.E.
      • Bland S.
      State estimates of household exposure to firearms, loaded firearms, and handguns, 1991 through 1995.
      ; and (2) the proportion of suicides in a state that used firearms,
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      which is a proxy measure of firearm ownership. Analysis of variance tests were performed that compared the three levels of restrictiveness laws on each index. Results in Table 2 suggest that state laws restricting firearms are associated with levels of gun ownership. A proxy is necessary because state-level data on ownership are unavailable for most states. Numerous proxy measures of firearm ownership have been used, and the proportion of suicides using a firearm has been demonstrated to be the best proxy of gun ownership.
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      The measure is an assessment of the proportion of firearms by suicides, not the firearm suicide rate. Miller et al.
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      have discussed the validity of the proportion of suicides by firearm as a proxy measure of firearm ownership. Support for the validity of this proxy measure includes consistent data across developed nations that the measure is highly correlated with firearm ownership, along with consistent regional-, state-, and city-level data from the United States that is strongly associated with gun ownership. Moreover, Miller et al.
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      have conducted a series of analyses demonstrating a zero correlation with overall rates of suicide, indicating that the proportion of suicides by firearm and overall suicide rates are independent constructs.
      Table 2Comparing firearm restrictiveness to measures of firearm ownership
      Gold standard measureUnrestrictive firearm lawsModest firearm lawsRestrictive firearm lawsANOVA
      Mean (SD)Mean (SD)Mean (SD)F (df)p value
      Percent of suicides using firearms
      Based on data aggregated in 1999 and 2000 with N = 50 states: 20 unrestrictive, 22 modest, and 8 restrictive.
      65.0
      ,
      (7.1)
      56.6
      ,
      (7.2)
      38.2
      Values with dissimilar superscripts differed at p<0.01 using Scheffe post-hoc test.
      (11.0)
      33.4 (2.47)0.000
      Percent of households with a firearm
      Based on N = 21 states using survey data with N = 21 states: 9 unrestrictive, 8 modest, and 4 restrictive.
      48.1
      ,
      (8.2)
      38.5
      ,
      (12.0)
      18.5
      Values with dissimilar superscripts differed at p<0.05 using Scheffe post-hoc test.
      (8.1)
      12.5 (2.18)0.000
      ANOVA, analysis of variance; df, degrees of freedom; F, value of F-test; SD, standard deviation.
      a Based on data aggregated in 1999 and 2000 with N = 50 states: 20 unrestrictive, 22 modest, and 8 restrictive.
      b ,
      c ,
      d Values with dissimilar superscripts differed at p<0.01 using Scheffe post-hoc test.
      e Based on N = 21 states using survey data with N = 21 states: 9 unrestrictive, 8 modest, and 4 restrictive.
      f ,
      g Values with dissimilar superscripts differed at p<0.05 using Scheffe post-hoc test.
      The dependent variable was stratified by gender and consisted of the number (count) of suicides per year for each state. The count (male suicides, female suicides) was estimated by taking the mean of the age-adjusted suicide rate (male rate, female rate) in 1999 and 2000

      National Center for Injury Prevention and Control. Injury mortality reports, 1999–2000. WISQARS injury mortality reports, 1999 and Later. 2002. Available at: http://webapp.cdc.gov/sasweb/ncipc/mortrate10.html. Accessed November 1, 2002

      and then multiplying the mean rate by the state population (number of males, number of females). The use of suicide counts, instead of suicide rates, was needed to meet the requirements of Poisson regression. Age-adjusted counts were estimated, instead of taking actual counts, in order to account for state variability in age. The population estimates and age adjustments used to derive the rates were based on 2000 U.S. census data.

      U.S. Census Bureau. United States Census 2000. U.S. Department of Commerce, Economics and Statistics Administration, 2001

      Analyses

      Data were analyzed in April 2003 using SAS, version 8 (SAS Institute Inc., Cary NC, 2001). Poisson regression analyses were conducted to fit the data of age-adjusted suicide counts at the state level stratified by gender. The independent variable of interest was restrictiveness of state firearm laws; the restrictive category was set as the reference group. Covariates were three state population assessments—income, race, and urban–rural composition
      • Hemenway D.
      • Kennedy B.P.
      • Kawachi I.
      • Putnam R.D.
      Firearm prevalence and social capital.
      —that were operationalized as median income, percent white non-Hispanic, and percent rural, respectively. The estimates were based on 2000 U.S. census data.

      U.S. Census Bureau. United States Census 2000. U.S. Department of Commerce, Economics and Statistics Administration, 2001

      Restrictiveness of state firearm laws was entered without and with the covariates, alternatively. Model-fitting statistics indicated overdispersion; thus, corrections were made as recommended by Allison.

      Allison PD. Logistic regression using the SAS system: theory and applications. Cary NC: SAS Institute Inc., 1999

      Incidence rate ratios (IRRs) were obtained by exponentiating the beta coefficients derived from the Poisson regression analyses to express the association between restrictiveness of state firearm laws and rates of suicide for men and women. Negative binomial models are an alternative approach to overdispersion,
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      ,

      Allison PD. Logistic regression using the SAS system: theory and applications. Cary NC: SAS Institute Inc., 1999

      and so negative binomial models were also conducted. The pattern of results was comparable, and so data produced using negative binomial models are not shown.

      Results

      Results of the analyses of suicide rates stratified by gender are presented in Table 3. Results in both sets of analyses were comparable; statistical control for covariates had little impact on the IRRs. Compared to states with restrictive firearm laws, suicide incidence rates in men and women were higher in states with unrestrictive firearm laws and those with modest firearm laws, respectively. In the analysis of men adjusted for covariates, the IRRs were 1.49 (95% confidence interval [CI], 1.23–1.82) and 1.51 (95% CI, 1.27–1.79) for unrestrictive firearm laws and modest firearm laws, respectively. In the analysis of women adjusted for covariates, the IRRs were 1.55 (95% CI, 1.27–1.95) and 1.64 (95% CI, 1.34–2.01) for unrestrictive firearm laws and modest firearm laws, respectively.
      Table 3IRRs for suicide in states with unrestrictive and modest firearm laws compared to states with restrictive firearm laws
      Unadjusted IRRsAdjusted IRRs
      Adjusted IRRs control for covariates of income, race, and urban–rural composition.
      Unrestrictive firearm lawsModest firearm lawsUnrestrictive firearm lawsModest firearm laws
      IRR95% CIIRR95% CIIRR95% CIIRR95% CI
      Men1.531.33–1.741.481.31–1.671.491.23–1.821.511.27–1.79
      Women1.411.31–1.671.421.22–1.651.551.23–1.951.641.34–2.01
      CI, confidence interval; IRR, incidence rate ratio.
      a Adjusted IRRs control for covariates of income, race, and urban–rural composition.
      Regarding the first research question, in men and women there were higher incidence rates of suicide in states with modest and unrestrictive firearm laws, respectively, compared to states with restrictive firearm laws. Results support that greater state restrictions on firearms are associated with lower incidence rates of suicide. In light of the lower suicide rates associated with greater firearm restrictions, the findings did not support the method substitution hypothesis that firearm restrictions would merely be counterbalanced by the adoption of alternative methods of suicide. Regarding the second research question, the magnitude of the incidence rate ratios in men and women were comparable. Findings did not support that lesser firearm restrictions were associated with higher suicide incidence rates in men than women.

      Discussion

      There were greater incidence rates of suicide in states with modest and unrestrictive firearm laws compared to those with restrictive firearm laws. The data support the hypothesis that state firearm laws are associated with suicide, and contradict assertions that restrictions on access to lethal methods will simply be offset by the adoption of alternative methods of suicide. Two mechanisms are probably operating. First, not all individuals with a preferred method will choose an alternative if their initial preference is unavailable.
      • Miller M.
      • Hemenway D.
      The relationship between firearms and suicide a review of the literature.
      Second, even in cases where method substitution occurs, substitution may nonetheless increase the chances of survival given data that firearms are a particularly lethal method of attempting suicide.
      • Chapdelaine A.
      • Samson E.
      • Kimberly M.D.
      Firearm related injuries in Canada issues for prevention.
      ,
      • Spicer R.S.
      • Miller T.R.
      Suicide acts in 8 states incidence and evaluation.
      The results did not support the hypothesis that firearm availability is more strongly associated with suicide in men than in women. The data are consistent with a rigorous, cross-sectional study of firearm ownership/availability and suicide by states that also showed that firearms are associated with comparable risk for suicide in men and women.
      • Miller M.
      • Azrael D.
      • Hemenway D.
      Household firearm ownership and suicide rates in the United States.
      The higher proportion of men committing suicide with firearms may be an artifact of higher rates of gun ownership among men rather than a reflection of men's greater preference to commit suicide using a firearm per se. In support of this interpretation, the 1.7:1 proportion of men versus women that use firearms to commit suicide

      National Center for Injury Prevention and Control. Injury mortality reports, 1999–2000. WISQARS injury mortality reports, 1999 and Later. 2002. Available at: http://webapp.cdc.gov/sasweb/ncipc/mortrate10.html. Accessed November 1, 2002

      is very similar to the gender distribution of firearm ownership (1.9:1) and handgun ownership (1.7:1) in the general population.
      • Powell K.E.
      • Jacklin B.C.
      • Nelson D.E.
      • Bland S.
      State estimates of household exposure to firearms, loaded firearms, and handguns, 1991 through 1995.
      Nonetheless, greater suicide mortality among men is presumed to be associated with modest and unrestrictive firearm laws given that the rate of suicide among men is four times higher than among women in the United States.
      This study had a few limitations. Causality cannot be presumed given the cross-sectional design. Suicides using handguns versus other firearms could not be distinguished—a limitation in light of data indicating that handguns in particular are associated with suicide
      • Conwell Y.
      • Duberstein P.R.
      • Conner K.R.
      • Eberly S.
      • Cox C.
      • Caine E.D.
      Access to firearms and risk for suicide in late life.
      ,
      • Lester D.
      • Murrell M.
      The preventive effect of strict gun control laws on suicide and homicide.
      ,
      • Markush R.
      • Bartolucci A.
      Firearms and suicide in the United States.
      and that state firearm laws target handguns.

      Open Society Institute. Gun control in the United States: a comparative survey of state firearm laws. Open Society Institute's Center on Crime, Communities & Culture and the Funder's Collaborative for Gun Violence Prevention 2000, April 11, 2002. Available at: www.soros.org/crime/guncontrol.htm. Accessed November 1, 2002

      The measure of firearm restrictiveness did not allow for analyses of the impact of specific types of firearm legislation that may have differing effects on suicide.
      • Ludwig J.
      • Cook P.J.
      Homicide and suicide rates associated with implementation of the Brady Handgun Violence Prevention Act.
      ,
      • Boor M.
      • Bair J.H.
      Suicide rates, handgun control laws, and sociodemographic variables.
      The measure also did not consider the level of enforcement of the laws or firearms purchased illegally. Taking into consideration the 95% CIs, results also did not support the hypothesis that rates of suicide differed between states with modest firearm laws versus those with unrestrictive laws, which may suggest that the distinction between modest and restrictive firearm laws may not be meaningful, at least as concerns suicide. In the United States, certifications of suicide are less likely to be made in women than in men,
      • Rockett I.R.
      • Thomas B.M.
      Reliability and sensitivity of suicide certification in higher-income countries.
      attributable to the tendency of women to use less violent and potentially more ambiguous methods of suicide. Given that suicidal intent by women is more difficult to judge, data quality in analyses on women may be relatively poor.
      The study also had several strengths, including support for the firearm restrictiveness measure against established measures of firearm ownership; statistical control for measures of race, income, and urbanization; and tests of a priori hypotheses concerning method substitution and gender. Findings underscore that minimal firearm laws are a potent population-level exposure for suicide in both men and women. Firearm restrictions such as those proposed by the American College of Preventive Medicine
      American College of Preventive Medicine
      Preventing handgun injury American College of Preventive Medicine position statement.
      are an important consideration in the design of population-based suicide prevention efforts. The findings also contribute to a growing body of evidence that policies that reduce availability of lethal methods in general may also reduce suicide mortality.
      • Hawton K.
      • Townsend E.
      • Deeks J.
      • et al.
      Effects of legislation restricting pack sizes of paracetamol and salicylate on self poisoning in the United Kingdom before and after study.

      Acknowledgements

      Sean Meldrum, MS, and members of the University of Rochester Laboratory of Interpersonal Violence and Victimization and the Laboratory of Suicide Prevention (LSP) provided valuable input.

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