Background: Firearm ownership is strongly related to suicide risk, yet little is known about how much risk declines when ownership ends ("divestment").
Methods: Using data from 523,182 handgun owners, we estimated the effect of divesting and remaining divested versus never divesting on the risk of suicide and firearm-specific suicide. We used pooled logistic regression with inverse probability weighting, adjusting for demographic and area-level measures.
Results: The 5-year risk of suicide death was 25.6 per 10,000 persons with divestment and 15.2 per 10,000 persons with no divestment, corresponding to a risk difference of 10.4 per 10,000 persons. The 5-year risk of firearm-specific suicide death was 6.3 per 10,000 persons with divestment and 12.9 per 10,000 persons with no divestment, corresponding to a risk difference of-6.6 per 10,000 persons. Comparing divestment to no divestment, risks were elevated for deaths due to other causes proposed as negative control outcomes; we incorporated these estimates into a series of bias derivations to better understand the magnitude of unmeasured confounding.
Conclusions: Collectively, these estimates suggest that divestment reduces firearm suicide risk by 50% or more and likely reduces overall suicide risk as well, although future data collection is needed to fully understand the extent of biases such as unmeasured confounding.
Bibliographical noteFunding Information: This work is supported by a research grant from the American Foundation for Suicide Prevention (SRG-0-144-17). M.M.’s time is supported by the Joyce Foundation (SG-20-42115).
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