Video Abstract

Video Abstract

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BACKGROUND:

Despite being unable to purchase firearms directly, many adolescents have access to guns, leading to increased risk of injury and death. We sought to determine if the National Instant Criminal Background Check System (NICS) changed adolescents’ gun-carrying behavior.

METHODS:

We performed a repeated cross-sectional study using National Youth Risk Behavior Survey data from years 1993 to 2017. We used a survey-weighted multivariable logistic regression model to determine if the NICS had an effect on adolescent gun carrying, controlling for state respondent characteristics, state laws, state characteristics, the interaction between the NICS and state gun laws, and time.

RESULTS:

On average, 5.8% of the cohort reported carrying a gun. Approximately 17% of respondents who carried guns were from states with a universal background check (U/BC) provision at the point of sale, whereas 83% were from states that did not have such laws (P < .001). The model indicated that the NICS together with U/BCs significantly reduced gun carrying by 25% (adjusted relative risk = 0.75 [95% confidence interval: 0.566–0.995]; P = .046), whereas the NICS independently did not (P = .516).

CONCLUSIONS:

Adolescents in states that require U/BCs on all prospective gun buyers are less likely to carry guns compared with those in states that only require background checks on sales through federally licensed firearms dealers. The NICS was only effective in reducing adolescent gun carrying in the presence of state laws requiring U/BCs on all prospective gun buyers. However, state U/BC laws had no effect on adolescent gun carrying until after the NICS was implemented.

What’s Known on This Subject:

Adolescents obtain guns from friends and family members. The National Instant Criminal Background Check System (NICS) was implemented to prevent firearm sales to individuals with criminal records. Not all states require background checks, producing variation in accessibility to and availability of guns for both adults and minors.

Our study suggests that the NICS alone does not decrease gun-carrying behaviors in adolescents. However, adolescents residing in states with laws that require background checks for all firearm purchases did have reduced gun carrying after NICS implementation.

To our knowledge, no study has specifically investigated whether the NICS reduces adolescent gun carrying. Research has primarily been focused on firearm-related deaths, and few studies have examined effects of laws on gun-carrying behavior in adolescents, a population at increased risk for firearm mishandling.17  Our objective for this study is to determine if the NICS affects adolescent gun carrying, controlling for and examining interactions with state background check laws. We hypothesize that the NICS serves as a tool for providing timely and more thorough background checks yet may be less effective at reducing adolescent gun carrying in states that do not require background checks for all gun sales.

We collected cross-sectional survey data from the national, school-based Youth Risk Behavior Survey (YRBS) from 1993 to 2017. The YRBS is a biennial survey conducted by the Centers for Disease Control and Prevention. With a 3-staged cluster-sampling survey design, data from the YRBS provides a nationally representative sample of US public and private school students in grades 9 to 12. A self-administered questionnaire is used to collect anonymous and voluntary responses from participating students on their demographics and health risk behaviors. In total, there were 191 391 responses over the period between 1993 and 2017. Details about YRBS sampling strategies and methodologies are reported elsewhere.18

Approximately 2.0% of the responses were missing state identifiers and 4.1% were missing information on the gun carrying survey item, so these responses were dropped from the analysis. Our final analysis included responses from 179 857 students from 1993 to 2017.

#### Gun Carrying

The YRBS in 1993–2015 was used to assess whether students carried guns by asking “During the past 30 days, on how many days did you carry a gun?” We dichotomized this question to flag those students who carried a gun on at least 1 day during the 30 days before the survey. In 2017, this question was modified to “During the past 12 months, on how many days did you carry a gun? (Do not count the days when you carried a gun only for hunting or for a sport, such as target shooting).” We used this question to flag the students if they carried a gun for at least 1 day in the past 12 months.

#### Pre- and Post-NICS

In November 1998, the Federal Bureau of Investigation launched the NICS. We used 1998 as the reference point and created the binary variable pre- and post-NICS period for YRBS data before and after 1998. Because the YRBS is biennial, data from years 1993–1997 were classified as pre-NICS, and data from years 1999–2017 were classified as post-NICS.

#### Universal Background Check

We created a data set of those states that have a requirement for a background check at the point of sale of any firearm. States, including California (1991), Colorado (2013), Connecticut (2013), Delaware (2013), the District of Columbia (1975), Maryland (2010), New York (2013), Oregon (2015), Pennsylvania (2010), Rhode Island (1990), and Washington (2014), have implemented universal background checks (U/BCs) either by requiring background checks for all gun sales conducted by licensed sellers only or by requiring licensed gun sellers, in addition to private sellers, to conduct background checks on all prospective buyers.16  Eight states, Hawaii (2013), Illinois (2013), Massachusetts (2006), New Jersey (2011), Iowa (2011), Michigan (2006), Nebraska (2010), and North Carolina (2014), implemented firearm background check requirements on private sales primarily by prohibiting private sellers to sell to buyers who did not have a requisite state license or permit and by requiring a background check before issuing the license or permit. Two of these states, Connecticut and New York, require both U/BCs and state permits to purchase firearms.

The YRBS responses were dichotomized into 2 groups: (1) respondents in states without any background check laws and (2) respondents in states with some background check laws at the point of sale or in states that require a license or permit after a background check, which was classified as U/BC. A state was identified as a U/BC state starting from the year when the law was enacted in that state.

#### Other Measures

Respondent-level variables included age, sex, race and ethnicity, state of residence, and whether the student reported any threat. The “threat” variable was obtained from the YRBS question “During the past 12 months, how many times has someone threatened or injured you with a weapon, such as a gun, knife, or club, on school property?” Studies have revealed that these variables are associated with the likelihood of gun carrying among adolescents.19,20  We also collected state-level data on annual estimates of median income in current and 2016 Consumer Price Index adjusted dollars and data on the percentage of the total population in urban areas from the decennial US Census.21,22

Univariate, bivariate, and multivariable analyses were performed in Stata/SE version 14.2 (Stata Corp, College Station, TX) by using the svy command to account for the complex sample design of the national YRBS. All estimates presented in the results are weighted estimates. Weighted estimates, with appropriate accounting of the survey design, reflect the national population estimate. α was set at .05. t tests and χ2 tests were used to test bivariate associations. National estimates of the percentage of high school students carrying guns is reported as well as the percentage of students carrying guns by each study variable.

The longitudinal nature of the data set allowed us to examine the effect of U/BCs before and after implementation of the NICS given the availability of responses from states that had U/BC laws in place before the NICS was implemented. To address our study objective, a longitudinal multivariable logistic regression model was used to examine the effects of the NICS and state U/BCs while controlling for age, race, ethnicity, sex, feeling threatened, and state of residence. It also controlled for time-varying effects, including implementation of the NICS, state U/BC policies, and annual state characteristics, which includes median income and the percentage of the population living in rural areas. It was used to examine the effect of the pre- and post-NICS period on the U/BC variable by using an interaction term. The interaction term between U/BC state and pre- and post-NICS period was used to examine the simultaneous effect of the NICS and state-specific U/BC laws. A postestimation command in Stata (adjrr) was used to estimate the adjusted relative risks (ARRs) for each variable in the model. Subpopulation analyses within the svy command were done to examine the effect of U/BCs on the observations before and after 1998.

A sensitivity analysis used to examine nonfirearm weapon-carrying behavior, such as knives, was conducted to determine if laws targeting firearm purchases specifically affected gun carrying. In the sensitivity analysis, we compared students who reported carrying a weapon (but did not report carrying a gun) with those who did not carry a weapon.

On average, 5.8% of high school students in the United States carried guns across the entire study period. Of those who carried guns, ∼17% were from the states that had U/BCs at the point of gun sales, whereas 83% were from states that did not have U/BCs (P < .001). Adolescents who carried guns were older (16–18 years; P < .001), male (P < .001), and white (P < .001). Students who were threatened reported carrying guns more than those who were not (28% vs 6%; P < .001) (Table 1).

TABLE 1

Sample Characteristics, Nationally Weighted Sample

VariablesTotal SampleBy Gun-Carrying Behavior
No (n = 172 456)Yes (n = 10 544)P
Carried a gun, n (%)
No 172 456 (94.24) — — —
Yes 10 544 (5.76) — — —
NICS period, n (%)    <.001
Pre-NICS 41 591 (22.73) 38 680 (22.43) 2912 (27.61)
Post-NICS 141 409 (77.27) 133 777 (77.57) 7633 (72.39)
State U/BC, n (%)    <.001
No 141 506 (77.33) 132 720 (76.96) 8786 (83.322)
Yes 41 495 (22.67) 39 736 (23.04) 1758 (16.68)
Age, y, mean (SE) 16.07 (0.01) 16.06 (0.01) 16.12 (0.02) .007
Age group, n (%)
12–15 y 64 449 (35.31) 61 017 (35.47) 3432 (32.71) <.001
16–18 y 118 051 (64.69) 110 992 (64.53) 7059 (67.29)
Sex, n (%)    <.001
Male 93 081 (51.02) 83 942 (48.82) 9139 (87.24)
Female 89 344 (48.98) 88 007 (51.18) 1337 (12.76)
Race, n (%)
White 111 356 (61.46) 105 447 (61.75) 5909 (56.74) <.001
African American 24 875 (13.73) 23 052 (13.50) 1823 (17.51) <.001
Other 44 942 (24.81) 42 260 (24.75) 2682 (25.75) .221
Ethnicity, n (%)    .263
Non-Hispanic 163 384 (90.18) 153 942 (90.15) 9442 (90.66)
Hispanic 17 789 (9.82) 16 817 (9.85) 972 (9.34)
Any threat felt, n (%)    <.001
No 169 484 (92.70) 161 907 (93.97) 7576 (72.00)
Yes 13 338 (7.30) 10 392 (6.03) 2946 (28.00)
State median income, $, mean (SE) 45 769.29 (410.30) 45 900.13 (414.37) 43 629.28 (430.98) <.001 State rural population, % (SE) 22.80 (0.63) 22.62 (0.62) 25.74 (0.82) <.001 Year of survey, n (%) <.001 1993 15 092 (8.25) 13 913 (8.07) 1179 (11.18) 1995 10 369 (5.67) 9588 (5.56) 781 (7.41) 1997 16 130 (8.81) 15 178 (8.80) 952 (9.03) 1999 15 240 (8.33) 14 490 (8.40) 750 (7.11) 2001 13 107 (7.16) 12 359 (7.17) 748 (7.09) 2003 14 516 (7.93) 13 637 (7.91) 879 (8.34) 2005 13 441 (7.35) 12 713 (7.37) 728 (6.90) 2007 13 340 (7.29) 12 653 (7.34) 687 (6.52) 2009 15 741 (8.60) 14 805 (8.59) 936 (8.87) 2011 14 232 (7.78) 13 503 (7.83) 729 (6.92) 2013 13 270 (7.25) 12 539 (7.27) 731 (6.94) 2015 14 520 (7.93) 13 752 (7.97) 768 (7.28) 2017 14 004 (7.65) 13 327 (7.73) 677 (6.42) VariablesTotal SampleBy Gun-Carrying Behavior No (n = 172 456)Yes (n = 10 544)P Carried a gun, n (%) No 172 456 (94.24) — — — Yes 10 544 (5.76) — — — NICS period, n (%) <.001 Pre-NICS 41 591 (22.73) 38 680 (22.43) 2912 (27.61) Post-NICS 141 409 (77.27) 133 777 (77.57) 7633 (72.39) State U/BC, n (%) <.001 No 141 506 (77.33) 132 720 (76.96) 8786 (83.322) Yes 41 495 (22.67) 39 736 (23.04) 1758 (16.68) Age, y, mean (SE) 16.07 (0.01) 16.06 (0.01) 16.12 (0.02) .007 Age group, n (%) 12–15 y 64 449 (35.31) 61 017 (35.47) 3432 (32.71) <.001 16–18 y 118 051 (64.69) 110 992 (64.53) 7059 (67.29) Sex, n (%) <.001 Male 93 081 (51.02) 83 942 (48.82) 9139 (87.24) Female 89 344 (48.98) 88 007 (51.18) 1337 (12.76) Race, n (%) White 111 356 (61.46) 105 447 (61.75) 5909 (56.74) <.001 African American 24 875 (13.73) 23 052 (13.50) 1823 (17.51) <.001 Other 44 942 (24.81) 42 260 (24.75) 2682 (25.75) .221 Ethnicity, n (%) .263 Non-Hispanic 163 384 (90.18) 153 942 (90.15) 9442 (90.66) Hispanic 17 789 (9.82) 16 817 (9.85) 972 (9.34) Any threat felt, n (%) <.001 No 169 484 (92.70) 161 907 (93.97) 7576 (72.00) Yes 13 338 (7.30) 10 392 (6.03) 2946 (28.00) State median income,$, mean (SE) 45 769.29 (410.30) 45 900.13 (414.37) 43 629.28 (430.98) <.001
State rural population, % (SE) 22.80 (0.63) 22.62 (0.62) 25.74 (0.82) <.001
Year of survey, n (%)    <.001
1993 15 092 (8.25) 13 913 (8.07) 1179 (11.18)
1995 10 369 (5.67) 9588 (5.56) 781 (7.41)
1997 16 130 (8.81) 15 178 (8.80) 952 (9.03)
1999 15 240 (8.33) 14 490 (8.40) 750 (7.11)
2001 13 107 (7.16) 12 359 (7.17) 748 (7.09)
2003 14 516 (7.93) 13 637 (7.91) 879 (8.34)
2005 13 441 (7.35) 12 713 (7.37) 728 (6.90)
2007 13 340 (7.29) 12 653 (7.34) 687 (6.52)
2009 15 741 (8.60) 14 805 (8.59) 936 (8.87)
2011 14 232 (7.78) 13 503 (7.83) 729 (6.92)
2013 13 270 (7.25) 12 539 (7.27) 731 (6.94)
2015 14 520 (7.93) 13 752 (7.97) 768 (7.28)
2017 14 004 (7.65) 13 327 (7.73) 677 (6.42)

All percentages are column percentages. —, not applicable.

On average, we found a decline in gun carrying until 1999. Since 1999, the trend begins to plateau over time (Fig 1). When comparing states with and without U/BCs, we observe that before NICS implementation, there was no difference in adolescent gun-carrying rates between U/BC and non-U/BC states. However, a difference emerges and continues after 1999, with lower proportions of students reporting gun carrying in U/BC states than in non-U/BC states throughout the remaining study period (Fig 2).

FIGURE 1

Trends of high school students’ gun-carrying behavior, 1993–2017. The figure reveals trends of gun carrying among all adolescents from 1993 to 2017. Percentages are expressed as decimals.

FIGURE 1

Trends of high school students’ gun-carrying behavior, 1993–2017. The figure reveals trends of gun carrying among all adolescents from 1993 to 2017. Percentages are expressed as decimals.

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FIGURE 2

Trends of high school students’ gun-carrying behavior by non-U/BC and U/BC states, 1993–2017. Percentages are expressed as decimals.

FIGURE 2

Trends of high school students’ gun-carrying behavior by non-U/BC and U/BC states, 1993–2017. Percentages are expressed as decimals.

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The results of the pooled and stratified weighted multivariable logistic regression model are presented as ARRs of gun carrying by high school students. During the estimation process, we controlled for age, sex, race, ethnicity, threat, state-level median income, and state percentage of the population living in rural areas. The pooled model includes the interaction between the NICS and U/BC. The pooled model reveals that the interaction term is significant, indicating that the NICS with U/BC reduced the risk of gun carrying by 25% (ARR = 0.75 [95% confidence interval [CI]: 0.566–0.995]; P = .046). There was no significant effect of U/BCs during the pre-NICS period whereas, during the post-NICS period, adolescents in states with U/BCs had a 15% reduction in the risk of carrying guns (ARR = 0.85 [95% CI: 0.738–0.984]; P = .029). Boys, African Americans, and those who received threats had a significantly higher risk of carrying guns. In the pooled analysis, ethnicity was not associated with the risk of gun carrying. However, Hispanic students, compared with non-Hispanic students, in the pre-NICS model had a higher risk of gun carrying (ARR = 1.32 [95% CI: 1.03–1.69]; P = .028), whereas they had lower risk in the post-NICS period (ARR = 0.80 [95% CI: 0.72–0.89]; P < .001). Older students in the pre- (12%; ARR = 1.12; P < .001) and post-NICS (20%; ARR = 1.20; P < .001) periods had an increased risk of carrying guns compared with younger adolescents. For each percent increase in the rural population in the post-NICS period, the risk of gun carrying increased by 1.3% (P < .001). Median income had no effect on gun carrying in the post-NICS period (P = .464) (Table 2).

TABLE 2

ARRs of Carrying Guns, Nationally Weighted Sample

Pooled SamplePre-NICS YearsPost-NICS Years
ARR (95% CI)PARR (95% CI)PARR (95% CI)P
NICS period
Pre-NICS Reference — — — — —
Post-NICS 0.951 (0.819–1.106) .516 — — — —
State U/BC
No Reference — — — — —
Yes 1.170 (0.913–1.498) .215 1.101 (0.859–1.410) .448 0.852 (0.738–0.984) .029
NICS + U/BC 0.750 (0.566–0.995) .046 — — — —
Age group, y
12–15 Reference — — — — —
16–18 1.121 (1.052–1.195) .001 0.933 (0.809–1.076) .338 1.198 (1.118–1.284) <.001
Sex
Male Reference — — — — —
Female 0.171 (0.156–0.188) <.001 0.174 (0.140–0.215) <.001 0.169 (0.153–0.187) <.001
Race
White Reference — — — — —
African American 1.371 (1.242–1.513) <.001 1.764 (1.523–2.044) <.001 1.228 (1.080–1.395) .002
Other 1.280 (1.172–1.397) <.001 1.364 (1.098–1.694) .005 1.245 (1.133–1.367) <.001
Ethnicity
Non-Hispanic Reference — — — — —
Hispanic 0.937 (0.847–1.037) .210 1.32 (1.031–1.690) .028 0.800 (0.717–0.893) <.001
Any threat felt
No Reference — — — — —
Yes 4.029 (3.726–4.358) <.001 3.766 (3.188–4.449) <.001 4.127 (3.777–4.510) <.001
State median income, $, thousands 0.994 (0.987–1.001) .082 0.973 (0.962–0.985) <.001 0.997 (0.989–1.005) .464 State rural population, % 1.013 (1.008–1.017) <.001 1.008 (0.998–1.018) .102 1.013 (1.008–1.018) <.001 Pooled SamplePre-NICS YearsPost-NICS Years ARR (95% CI)PARR (95% CI)PARR (95% CI)P NICS period Pre-NICS Reference — — — — — Post-NICS 0.951 (0.819–1.106) .516 — — — — State U/BC No Reference — — — — — Yes 1.170 (0.913–1.498) .215 1.101 (0.859–1.410) .448 0.852 (0.738–0.984) .029 NICS + U/BC 0.750 (0.566–0.995) .046 — — — — Age group, y 12–15 Reference — — — — — 16–18 1.121 (1.052–1.195) .001 0.933 (0.809–1.076) .338 1.198 (1.118–1.284) <.001 Sex Male Reference — — — — — Female 0.171 (0.156–0.188) <.001 0.174 (0.140–0.215) <.001 0.169 (0.153–0.187) <.001 Race White Reference — — — — — African American 1.371 (1.242–1.513) <.001 1.764 (1.523–2.044) <.001 1.228 (1.080–1.395) .002 Other 1.280 (1.172–1.397) <.001 1.364 (1.098–1.694) .005 1.245 (1.133–1.367) <.001 Ethnicity Non-Hispanic Reference — — — — — Hispanic 0.937 (0.847–1.037) .210 1.32 (1.031–1.690) .028 0.800 (0.717–0.893) <.001 Any threat felt No Reference — — — — — Yes 4.029 (3.726–4.358) <.001 3.766 (3.188–4.449) <.001 4.127 (3.777–4.510) <.001 State median income,$, thousands 0.994 (0.987–1.001) .082 0.973 (0.962–0.985) <.001 0.997 (0.989–1.005) .464
State rural population, % 1.013 (1.008–1.017) <.001 1.008 (0.998–1.018) .102 1.013 (1.008–1.018) <.001

The pooled model includes data from the entire study period. The pre- and post-NICS models reflect data from those respective periods. —, reference category.

From the sensitivity analysis, we observed that U/BCs had no effect (P = .090) in the control condition (nonfirearm weapon carrying), helping to rule out the possibility of spurious associations between background checks and adolescent gun carrying (Table 3).

TABLE 3

Sensitivity Analysis to Estimate Nonfirearm Weapon-Carrying Behavior

Pooled Sample
aOR (95% CI)P
NICS period
Pre-NICS Reference —
Post-NICS 1.075 (0.947–1.221) .26
State U/BC
No Reference —
Yes 1.119 (0.913–1.371) .28
NICS + U/BC 0.825 (0.659–1.034) .09
Age group, y
12–15 Reference —
16–18 0.989 (0.942–1.038) .65
Sex
Male Reference —
Female 0.246 (0.231–0.263) <.001
Race
White Reference —
African American 0.736 (0.670–0.808) <.001
Other 0.957 (0.880–1.041) .31
Ethnicity
Non-Hispanic Reference —
Hispanic 0.928 (0.843–1.021) .13
Any threat felt
No Reference —
Yes 3.278 (3.032–3.545) <.001
State median income, $, thousands 0.992 (0.985–0.998) .01 State rural population, % 1.004 (1.001–1.008) .04 Pooled Sample aOR (95% CI)P NICS period Pre-NICS Reference — Post-NICS 1.075 (0.947–1.221) .26 State U/BC No Reference — Yes 1.119 (0.913–1.371) .28 NICS + U/BC 0.825 (0.659–1.034) .09 Age group, y 12–15 Reference — 16–18 0.989 (0.942–1.038) .65 Sex Male Reference — Female 0.246 (0.231–0.263) <.001 Race White Reference — African American 0.736 (0.670–0.808) <.001 Other 0.957 (0.880–1.041) .31 Ethnicity Non-Hispanic Reference — Hispanic 0.928 (0.843–1.021) .13 Any threat felt No Reference — Yes 3.278 (3.032–3.545) <.001 State median income,$, thousands 0.992 (0.985–0.998) .01
State rural population, % 1.004 (1.001–1.008) .04

aOR, adjusted odds ratio; —, reference category.

It is important to note that factors in addition to background check laws on adult gun purchases likely play a larger role in adolescent gun carrying. Adolescents often obtain firearms from their own home, purchased legally by adults who may not always secure weapons (either within a safe or using another locking mechanism).34  A cross-sectional survey of adolescents attending New York City high schools on their perception of firearms revealed that 41% of students lived with an adult who possessed a firearm.34  These students were more likely to be found in residences with gun-supporting families that witnessed gun violence at some point in their lives. Thus, gun-safety storage programs may be beneficial to both rural- and urban-dwelling families, particularly those with high school youth, because researchers found these programs to be helpful across populations.35  Storing firearms securely reduces the likelihood that a minor residing in the home would obtain it without an adult’s knowledge as well as prevents gun theft, which is an important source of guns used in crimes or possibly sold in illegal markets to minors.36

With our study, we add to the literature by examining how federal and state policy changes over a 24-year period, approximately a generation, interact to affect adolescent gun carrying. Specifically, we found that state laws moderate the effect of federal background check laws, which may suggest that implementing U/BCs at the national level could increase efficacy of the NICS. The NICS background check system is limited because of the potential to sidestep the system through private sales. Implementing U/BCs nationally may decrease the number of guns accessible to adolescents and, in turn, reduce their gun carrying. On the basis of studies in adults, this could also indirectly prevent firearm-related suicides, homicides, and injuries as well as reduce the likelihood of being charged with a felony that could affect employment opportunities throughout life.33,3740  Strengthening background check policies and making safety training available to all gun owners on proper storage of firearms may decrease the number of firearms acquired by adolescents, preventing injuries that are costly both financially and to quality of life.4143

Our findings suggest that federal systems for conducting background checks do not independently reduce adolescent gun carrying on a national level. This may be because the NICS effect was only significant in the presence of state U/BC laws. Additionally, U/BC laws did not independently affect adolescent gun carrying before implementation of the NICS. Therefore, it is possible that both federal and state background check laws work together to reduce gun carrying in high school students.

Dr Timsinia performed the data analysis and drafted the manuscript; Dr Qiao assisted in the study design, acquired data, and drafted the manuscript; Mr Mongalo drafted the manuscript; Ms Vetor drafted the manuscript and interpreted results; Dr Carroll provided critical feedback on the study design, interpreted results, and made critical manuscript revisions; Dr Bell conceptualized and designed the study, interpreted results, and drafted the manuscript; and all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

FUNDING: Supported by grants KL2TR002530 and UL1TR002529 from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical and Translational Science Awards Program. Funded by the National Institutes of Health (NIH).

COMPANION PAPER: A companion to this article can be found online at www.pediatrics.org/cgi/doi/10.1542/peds.2019-2334.

• ARR

•
• CI

confidence interval

•
• NICS

National Instant Criminal Background Check System

•
• U/BC

universal background check

•
• YRBS

Youth Risk Behavior Survey

1
Casey
BJ
,
Jones
RM
,
Hare
TA
.
.
.
2008
;
1124
:
111
126
2
Giffords Law Center to Prevent Gun Violence
.
Minimum age to purchase & possess.
2016
. Available at: http://lawcenter.giffords.org/gun-laws/policy-areas/who-can-have-a-gun/minimum-age/. Accessed August 9, 2018
3
Teret
SP
,
Wintemute
GJ
.
Policies to prevent firearm injuries
.
Health Aff (Millwood)
.
1993
;
12
(
4
):
96
108
4
Hemenway
D
.
Reducing firearm violence
.
Crime Justice
.
2017
;
46
(
1
):
201
230
5
Rattan
R
,
Parreco
J
,
Namias
N
,
Pust
GD
,
Yeh
DD
,
Zakrison
TL
.
Hidden costs of hospitalization after firearm injury: national analysis of different hospital readmission
.
Ann Surg
.
2018
;
267
(
5
):
810
815
6
Spitzer
SA
,
Staudenmayer
KL
,
Tennakoon
L
,
Spain
DA
,
Weiser
TG
.
Costs and financial burden of initial hospitalizations for firearm injuries in the United States, 2006-2014
.
Am J Public Health
.
2017
;
107
(
5
):
770
774
7
Howell
EM
,
Abraham
P
.
The Hospital Costs of Firearm Assaults
.
Washington, DC
:
Urban Institute
;
2013
8
Center for Disease Control and Prevention
.
Youth violence: facts at a glance.
2016
. Available at: https://www.cdc.gov/violenceprevention/pdf/yv-datasheet.pdf. Accessed August 9, 2018
9
Harvard Injury Control Research Center
;
Suicide Prevention Resource Center
.
Youth Suicide: Findings From a Pilot for the National Violent Death Reporting System
.
Waltham, MA
:
Suicide Prevention Resource Center
;
2007
10
Giffords Law Center to Prevent Gun Violence
.
The California model: twenty years of putting safety first.
2013
. Available at: http://lawcenter.giffords.org/the-california-model-twenty-years-of-putting-safety-first/. Accessed August 9, 2018
11
Ludwig
J
,
Cook
PJ
.
Homicide and suicide rates associated with implementation of the Brady Handgun Violence Prevention Act
.
JAMA
.
2000
;
284
(
5
):
585
591
12
Federal Bureau of Investigation
. National Instant Criminal Background Check System (NICS).
2013
. Available at: https://www.fbi.gov/services/cjis/nics#Reports-%20Statistics. Accessed August 9, 2018
13
Giffords Law Center to Prevent Gun Violence
.
Background check procedures.
2016
. Available at: http://lawcenter.giffords.org/gun-laws/policy-areas/background-checks/background-check-procedures/. Accessed August 9, 2018
14
Federal Bureau of Investigation
. NICS firearm checks: month/year.
2018
. Available at: https://www.fbi.gov/file-repository/nics_firearm_checks_-_month_year.pdf/view. Accessed August 9, 2018
15
Federal Bureau of Investigation
.
Federal denials.
2018
. Available at: https://www.fbi.gov/file-repository/federal_denials.pdf/view. Accessed August 9, 2018
16
Giffords Law Center to Prevent Gun Violence
.
Universal background checks. 2016. Available at: http://lawcenter.giffords.org/gun-laws/policy-areas/background-checks/universal-background-checks/. Accessed October 11, 2018
17
Xuan
Z
,
Hemenway
D
.
State gun law environment and youth gun carrying in the United States
.
JAMA Pediatr
.
2015
;
169
(
11
):
1024
1031
18
Brener
ND
,
Kann
L
,
Shanklin
S
, et al;
Centers for Disease Control and Prevention
.
Methodology of the Youth Risk Behavior Surveillance System–2013
.
MMWR Recomm Rep
.
2013
;
62
(
RR-1
):
1
20
19
Pham
TB
,
Schapiro
LE
,
John
M
,
A
.
Weapon carrying among victims of bullying
.
Pediatrics
.
2017
;
140
(
6
):
e20170353
20
Kemal
S
,
Sheehan
K
,
Feinglass
J
.
Gun carrying among freshmen and sophomores in Chicago, New York City and Los Angeles public schools: the Youth Risk Behavior Survey, 2007-2013
.
Inj Epidemiol
.
2018
;
5
(
suppl 1
):
12
21
Iowa State University Iowa Community Indicators Program
;
Iowa State University
.
Urban Percentage of the Population for States, Historical
.
Ames, IA
:
2018
22
US Census Bureau
.
Current population survey.
Available at: https://www.census.gov/programs-surveys/cps/data-detail.html. Accessed November 7, 2018
23
Miller
M
,
Hepburn
L
,
Azrael
D
.
Firearm acquisition without background checks: results of a national survey
.
Ann Intern Med
.
2017
;
166
(
4
):
233
239
24
Matthay
EC
,
Galin
J
,
Rudolph
KE
,
Farkas
K
,
Wintemute
GJ
,
Ahern
J
.
In-state and interstate associations between gun shows and firearm deaths and injuries: a quasi-experimental study
.
Ann Intern Med
.
2017
;
167
(
12
):
837
844
25
Wintemute
GJ
,
Wright
MA
,
Drake
CM
,
Beaumont
JJ
.
Subsequent criminal activity among violent misdemeanants who seek to purchase handguns: risk factors and effectiveness of denying handgun purchase
.
JAMA
.
2001
;
285
(
8
):
1019
1026
26
Perkins
C
.
National Crime Victimization Survey, 1993-2001: Weapon Use and Violent Crime
.
Washington, DC
:
Bureau of Justice Statistics
;
2003
27
Miller
M
,
Azrael
D
,
Hemenway
D
.
Firearm availability and unintentional firearm deaths, suicide, and homicide among 5-14 year olds
.
J Trauma
.
2002
;
52
(
2
):
267
274–275
28
Ruddell
R
,
Mays
GL
.
State background checks and firearms homicides
.
J Crim Justice
.
2005
;
33
(
2
):
127
136
29
Alban
RF
,
Nuño
M
,
Ko
A
,
Barmparas
G
,
Lewis
AV
,
Margulies
DR
.
Weaker gun state laws are associated with higher rates of suicide secondary to firearms
.
J Surg Res
.
2018
;
221
:
135
142
30
Qiao
N
,
Bell
TM
.
Indigenous adolescents’ suicidal behaviors and risk factors: evidence from the National Youth Risk Behavior Survey
.
J Immigr Minor Health
.
2017
;
19
(
3
):
590
597
31
Bell
TM
,
Qiao
N
,
Jenkins
PC
,
Siedlecki
CB
,
Fecher
AM
.
Trends in emergency department visits for nonfatal violence-related injuries among adolescents in the United States, 2009-2013
.
.
2016
;
58
(
5
):
573
575
32
Monuteaux
MC
,
Lee
LK
,
Hemenway
D
,
Mannix
R
,
Fleegler
EW
.
Firearm ownership and violent crime in the U.S.: an ecologic study
.
Am J Prev Med
.
2015
;
49
(
2
):
207
214
33
Lee
LK
,
Fleegler
EW
,
Farrell
C
, et al
.
Firearm laws and firearm homicides: a systematic review
.
JAMA Intern Med
.
2017
;
177
(
1
):
106
119
34
Kahn
DJ
,
Kazimi
MM
,
Mulvihill
MN
.
Attitudes of New York City high school students regarding firearm violence
.
Pediatrics
.
2001
;
107
(
5
):
1125
1132
35
Coyne-Beasley
T
,
Schoenbach
VJ
,
Johnson
RM
.
“Love our kids, lock your guns”: a community-based firearm safety counseling and gun lock distribution program
.
.
2001
;
155
(
6
):
659
664
36
Hemenway
D
,
Azrael
D
,
Miller
M
.
Whose guns are stolen? The epidemiology of gun theft victims
.
Inj Epidemiol
.
2017
;
4
(
1
):
11
37
Grossman
DC
,
Mueller
BA
,
Riedy
C
, et al
.
Gun storage practices and risk of youth suicide and unintentional firearm injuries
.
JAMA
.
2005
;
293
(
6
):
707
714
38
Parikh
K
,
Silver
A
,
Patel
SJ
,
Iqbal
SF
,
Goyal
M
.
Pediatric firearm-related injuries in the United States
.
Hosp Pediatr
.
2017
;
7
(
6
):
303
312
39
Joudi
N
,
Tashiro
J
,
Golpanian
S
,
Eidelson
SA
,
Perez
EA
,
Sola
JE
.
Firearm injuries due to legal intervention in children and adolescents: a national analysis
.
J Surg Res
.
2017
;
214
:
140
144
40
Tseng
J
,
Nuño
M
,
Lewis
AV
,
Srour
M
,
Margulies
DR
,
Alban
RF
.
Firearm legislation, gun violence, and mortality in children and young adults: a retrospective cohort study of 27,566 children in the USA
.
Int J Surg
.
2018
;
57
:
30
34
41
Hepburn
L
,
Azrael
D
,
Miller
M
,
Hemenway
D
.
The effect of child access prevention laws on unintentional child firearm fatalities, 1979-2000
.
J Trauma
.
2006
;
61
(
2
):
423
428
42
Tashiro
J
,
Lane
RS
,
Blass
LW
,
Perez
EA
,
Sola
JE
.
The effect of gun control laws on hospital admissions for children in the United States
.
J Trauma Acute Care Surg
.
2016
;
81
(
4
suppl 1
):
S54
S60
43
Monuteaux
MC
,
Azrael
D
,
Miller
M
.
Association of increased safe household firearm storage with firearm suicide and unintentional death among US youths
.
JAMA Pediatr
.
2019
;
173
(
7
):
657
662

## Competing Interests

POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.

FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.