Background

Research suggests that access to firearms in the home increases the risk for violent death.

Purpose

To understand current estimates of the association between firearm availability and suicide or homicide.

Data Sources

PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, and Web of Science were searched without limitations and a gray-literature search was performed on 23 August 2013.

Study Selection

All study types that assessed firearm access and outcomes between participants with and without firearm access. There were no restrictions on age, sex, or country.

Data Extraction

Two authors independently extracted data into a standardized, prepiloted data extraction form.

Data Synthesis

Odds ratios (ORs) and 95% CIs were calculated, although published adjusted estimates were preferentially used. Summary effects were estimated using random- and fixed-effects models. Potential methodological reasons for differences in effects through subgroup analyses were explored. Data were pooled from 16 observational studies that assessed the odds of suicide or homicide, yielding pooled ORs of 3.24 (95% CI, 2.41 to 4.40) and 2.00 (CI, 1.56 to 3.02), respectively. When only studies that used interviews to determine firearm accessibility were considered, the pooled OR for suicide was 3.14 (CI, 2.29 to 4.43).

Limitations

Firearm accessibility was determined by survey interviews in most studies; misclassification of accessibility may have occurred. Heterogeneous populations of varying risks were synthesized to estimate pooled odds of death.

Conclusion

Access to firearms is associated with risk for completed suicide and being the victim of homicide.