Ellicott C. Matthay, MPH; Jessica Galin, MPH; Kara E. Rudolph, PhD, MPH, MHS; Kriszta Farkas, MPH; Garen J. Wintemute, MD, MPH; Jennifer Ahern, PhD, MPH
Disclaimer: The analyses, interpretations, and conclusions of this report are attributable to the authors and not to the California Department of Public Health or National Institutes of Health.
Acknowledgment: The authors thank the following funding sources: the Eunice Kennedy Shriver National Institute of Child Health and Human Development; the National Institutes of Health Office of the Director; the University of California, Berkeley Committee on Research; and the Heising-Simons Foundation.
Grant Support: By grant DP2HD080350 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institutes of Health Office of the Director (Ms. Matthay, Ms. Galin, Ms. Farkas, and Dr. Ahern); the University of California, Berkeley Committee on Research (Ms. Matthay, Ms. Galin, Ms. Farkas, and Dr. Ahern); and grant 2016-219 from the Heising-Simons Foundation (Dr. Wintemute).
Disclosures: Ms. Matthay, Ms. Galin, Ms. Farkas, and Dr. Ahern report grants from the National Institutes of Health and University of California, Berkeley, during the conduct of the study. Dr. Wintemute reports grants from Heising-Simons Foundation during the conduct of the study. Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M17-1792.
Editors' Disclosures: Christine Laine, MD, MPH, Editor in Chief, reports that she has no financial relationships or interests to disclose. Darren B. Taichman, MD, PhD, Executive Deputy Editor, reports that he has no financial relationships or interests to disclose. Cynthia D. Mulrow, MD, MSc, Senior Deputy Editor, reports that she has no relationships or interests to disclose. Deborah Cotton, MD, MPH, Deputy Editor, reports that she has no financial relationships or interest to disclose. Jaya K. Rao, MD, MHS, Deputy Editor, reports that she has stock holdings/options in Eli Lilly and Pfizer. Sankey V. Williams, MD, Deputy Editor, reports that he has no financial relationships or interests to disclose. Catharine B. Stack, PhD, MS, Deputy Editor for Statistics, reports that she has stock holdings in Pfizer and Johnson & Johnson.
Reproducible Research Statement:Study protocol: Not applicable. Statistical code: Available from Ellicott Matthay (e-mail, ematthay@berkeley.edu). Data set: Death and hospital visit data are available from the California Department of Public Health Vital Records and the Office of Statewide Health Planning and Development; data on dates and locations of gun shows are available from Ellicott Matthay (e-mail, ematthay@berkeley.edu).
Requests for Single Reprints: Ellicott C. Matthay, MPH, 50 University Hall, University of California, Berkeley, Berkeley, CA 94704; e-mail, ematthay@berkeley.edu.
Current Author Addresses: Ms. Matthay, Ms. Galin, Drs. Rudolph and Ahern, and Ms. Farkas: 50 University Hall, University of California, Berkeley, Berkeley, CA 94704.
Dr. Wintemute: Violence Prevention Research Program, UC Davis Medical Center, 2315 Stockton Boulevard, Sacramento, CA 95817.
Author Contributions: Conception and design: E.C. Matthay, J. Galin, K.E. Rudolph, G. Wintemute, J. Ahern.
Analysis and interpretation of the data: E.C. Matthay, J. Galin, K.E. Rudolph, G. Wintemute, J. Ahern.
Drafting of the article: E.C. Matthay, J. Galin, J. Ahern.
Critical revision of the article for important intellectual content: E.C. Matthay, K.E. Rudolph, K. Farkas, G. Wintemute, J. Ahern.
Final approval of the article: E.C. Matthay, J. Galin, K.E. Rudolph, K. Farkas, G. Wintemute, J. Ahern.
Provision of study materials or patients: G. Wintemute.
Statistical expertise: E.C. Matthay, K.E. Rudolph.
Obtaining of funding: G. Wintemute, J. Ahern.
Administrative, technical, or logistic support: E.C. Matthay, J. Galin.
Collection and assembly of data: E.C. Matthay, J. Galin, K. Farkas, G. Wintemute, J. Ahern.
Gun shows are an important source of firearms, but no adequately powered studies have examined whether they are associated with increases in firearm injuries.
To determine whether gun shows are associated with short-term increases in local firearm injuries and whether this association differs by the state in which the gun show is held.
Quasi-experimental.
California.
Persons in California within driving distance of gun shows.
Gun shows in California and Nevada between 2005 and 2013 (n = 915 shows) and rates of firearm-related deaths, emergency department visits, and inpatient hospitalizations in California.
Compared with the 2 weeks before, postshow firearm injury rates remained stable in regions near California gun shows but increased from 0.67 injuries (95% CI, 0.55 to 0.80 injuries) to 1.14 injuries (CI, 0.97 to 1.30 injuries) per 100 000 persons in regions near Nevada shows. After adjustment for seasonality and clustering, California shows were not associated with increases in local firearm injuries (rate ratio [RR], 0.99 [CI, 0.97 to 1.02]) but Nevada shows were associated with increased injuries in California (RR, 1.69 [CI, 1.16 to 2.45]). The pre–post difference was significantly higher for Nevada shows than California shows (ratio of RRs, 1.70 [CI, 1.17 to 2.47]). The Nevada association was driven by significant increases in firearm injuries from interpersonal violence (RR, 2.23 [CI, 1.01 to 4.89]) but corresponded to a small increase in absolute numbers. Nonfirearm injuries served as a negative control and were not associated with California or Nevada gun shows. Results were robust to sensitivity analyses.
Firearm injuries were examined only in California, and gun show occurrence was not randomized.
Gun shows in Nevada, but not California, were associated with local, short-term increases in firearm injuries in California. Differing associations for California versus Nevada gun shows may be due to California's stricter firearm regulations.
National Institutes of Health; University of California, Berkeley; and Heising-Simons Foundation.
Appendix Table 1. ICD-9 and ICD-10 External Cause-of-Injury Codes Used to Identify and Classify Firearm Deaths and Injuries
Comparison of observed and simulated distribution of firearm deaths and injuries during the 2 weeks after gun shows in nearby regions.
The unit of analysis is the gun show. The figure presents the distribution of the observed and simulated number of firearm deaths and injuries, per gun show, ≤2 wk after each gun show, in regions within driving distance of each show, by state. For example, in both the observed and simulated data, just fewer than 300 gun show regions had no firearm deaths or injuries ≤2 wk after the show.
Table 1. Characteristics of California and Nevada Gun Shows and Population Exposure to Gun Shows
Locations of gun shows in California and Nevada.
Table 2. Unadjusted Analyses of the Association Between Firearm Deaths and Injuries in California and Gun Shows in California and Nevada
Table 3. Adjusted Analyses of the Association Between Firearm Deaths and Injuries in California and Gun Shows in California Versus Nevada
Table 4. Adjusted Analyses of the Association Between Firearm Deaths and Injuries in California and Gun Shows in California and Nevada, by State
Table 5. Adjusted Analyses of the Association Between Firearm Deaths and Injuries in California and Gun Shows in California Versus Nevada, Restricted to Regions Similar to Those Exposed to Nevada Gun Shows
Appendix Table 2. Secondary Analyses for the Adjusted Association Between Firearm Deaths and Injuries Along Firearm Trafficking Routes and Excluding California's 10-Day Waiting Period
Appendix Table 3. Sensitivity Analyses for the Adjusted Association Between Firearm Deaths and Injuries in California and Gun Shows in California Versus Nevada
Appendix Table 4. Distribution of Characteristics of Regions Exposed to Gun Shows Before and After Restriction to Regions Similar to Those Exposed to Nevada Gun Shows
Appendix Table 5. Negative Control Analysis for the Adjusted Association Between Nonfirearm Injury Deaths and Hospital Visits in California and Gun Shows in California Versus Nevada
Bias analysis results for the association between Nevada gun shows and California firearm deaths and injuries.
Each graph represents a scenario for the prevalence of U among the exposed (P(U = 1|a = 1,x), which ranges from 0.1 to 0.8). In each plot, the x-axis measures the association between the unmeasured confounder and firearm deaths and injuries in California, the color of each line indicates the association between the unmeasured confounder and exposure to Nevada gun shows, and the y-axis displays the corrected lower confidence bound for the given bias scenario. For example, when the prevalence of U is 0.1, the RR for the U–gun shows association is 3, and the RR for the U–firearm deaths and injuries association is 3, then the association between Nevada gun shows and California firearm deaths and injuries would still be statistically significant, with a corrected lower confidence bound above 1. RR = rate ratio.
Bias analysis results for the association between state of gun show and increases in firearm deaths and injuries after gun shows.
Each graph represents a scenario for the prevalence of U for Nevada gun shows (P(U = 1|a = 1,x), which ranges from 0.1 to 0.8). In each plot, the x-axis measures the association between the unmeasured confounder and increases in firearm deaths and injuries after gun shows, the color of each line indicates the association between the unmeasured confounder and the state of the gun show, and the y-axis displays the corrected lower confidence bound for the given bias scenario. For example, when the prevalence of U is 0.1 for Nevada gun shows, the RR for the U–A association is 3, and the RR for the U–Y association is 3, then the association between the state of the gun show and increases in firearm death and injuries after gun shows would still be statistically significant, with a corrected lower confidence bound above 1. RR = rate ratio.
Terms of Use
The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.
Michael Xu
UTHSC
October 24, 2017
IIlegal
It is already federal crime in all states for both private individuals and businesses to sell a firearm across state borders without background check. A California resident cannot drive to NV, buy a firearm, and then travel back to California. He or she must buy the firearm, have the private individual/business transfer the firearm to a California firearm dealer, at which time a back ground check will be conducted.
Seth Breitbart
EHMC
January 3, 2018
Politically Motivated Pseudoscience
As the previous commenter, Michael Xu, correctly stated, it is already a federal crime in all 50 states for both private individuals and businesses to sell a firearm across state borders without a background check. It is also illegal for a person to buy a gun in a state where he/she does not maintain a residence. Again, as Michael Xu correctly stated, a California resident cannot drive to Nevada, buy a firearm, and then travel back to California: Such transaction is already illegal. If, for example, a California resident wants to buy a gun from a seller from Nevada. The California resident and the Nevada gun seller must go through several steps. First, the California resident contacts his local FFL (e.g. a local gun store where a background check can be done) and tells them that he wants to buy an out of state gun. Next, he will pay the Nevada gun seller. The Nevada gun seller will then transfer the gun to the gun store designated by the buyer, where a background check will be completed. For this, the California resident must pay another fee. Thus, the entire argument of this article, which infers that California residents are travelling over the state border to legally buy guns at Nevada guns shows, is verifiably untrue. It is a shame that the Annals of Internal Medicine would publish such a clearly politically motivated article that and can be debunked at a glance.
Alan R. Ertle, MD, MPH, MBA
Mercy Medical Group, Inc.
Highly Questionable Association
It is likely that everyone in a health profession in the United States agrees that there is too much gun violence and too many firearms-related injuries. Matthay and colleagues’ study attempts to make an association between the relatively under-regulated gun shows of Nevada and the increase in firearm death and injuries in the immediate post-gun-show period in California zip codes where those California populations were deemed close enough to drive to both certain California and Nevada gun shows. What stands out first is the difference in total firearm death and injuries for California-based gun shows versus Nevada-based gun shows. In the two weeks after gun shows there were 14,893 total firearm deaths and injuries after California-based gun shows and 74 total firearm deaths and injuries for Nevada-based gun shows, or about 0.5% of the California-based gun show total. These numbers are totals for the eight-year period of the study. This vast difference in raw number of events during the eight-year study period must point out an equally vast difference in measured at-risk populations in California between California-based and Nevada-based gun shows, despite a much closer number of total gun shows analyzed in the final regression for California (585) and Nevada (161). One can think about the raw data in several different ways. For the Nevada-based gun shows, there are about 5.5 gun-related events per year in the two weeks running up to the gun shows (44 events over 8 years) and 9.25 gun-related events per year in the two weeks after (74 events over 8 years). Alternatively, there was an average of 0.27 gun-related events per Nevada-based gun show in the two weeks prior to the guns shows (44 events and 161 gun shows) and there was an average of 0.45 gun-related events per Nevada-based gun show in the two weeks after (74 events and 161 gun shows). On the surface, the total firearm deaths and injuries in the study population before and after the Nevada-based gun shows seems to be quite small, particular given the eight-year study period and 161 analyzed Nevada-based gun shows. It calls into question whether the power calculation to actually determine true differences rather than by-chance differences was accurate. Additionally, it is not clear if anyone from California actually went to the Nevada-based gun shows, whether they actually purchased weapons or ammunition at the Nevada-based gun shows, or whether any weapon or ammunition from a Nevada-based gun show was actually used to conduct firearms-related violence in any of the California incidents measured in the two-week post-gun-show period. It would seem that it would be necessary to have this data in order to make any assertion that Nevada-based gun shows had anything to do with the events they measured. If you put one variable into a model, it is always likely that you will find an association if you look hard enough. I find the study totally underwhelming and highly questionable in its conclusion that, “Firearm injuries in California remained stable after California gun shows but increased by a small but significant amount after Nevada shows.”
Matthay EC, Galin J, Rudolph KE, et al. In-State and Interstate Associations Between Gun Shows and Firearm Deaths and Injuries: A Quasi-experimental Study. Ann Intern Med. 2017;167:837–844. [Epub ahead of print 7 November 2017]. doi: https://doi.org/10.7326/M17-1792
Download citation file:
© 2019
Published: Ann Intern Med. 2017;167(12):837-844.
DOI: 10.7326/M17-1792
Published at www.annals.org on 7 November 2017
Hospital Medicine.