Smoking and Secondhand Smoke Linked to Serious Injuries in Teens Across 58 Countries

Serious injuries are one of the leading causes of death among adolescents worldwide, yet the behavioral and environmental factors that shape a young person’s risk of being hurt have remained surprisingly underexplored. A new multinational study published in the journal Air Quality, Atmosphere & Health now adds a striking piece to that puzzle. Drawing on data from 176,635 adolescents aged 12 to 17 years across 58 countries, researchers found that both active tobacco and substitute product use and exposure to secondhand smoke were significantly associated with a higher likelihood of reporting a serious injury. The findings, based on the World Health Organization’s Global School-based Student Health Survey conducted between 2013 and 2019, suggest that the harms of tobacco exposure in adolescence may extend well beyond the well-documented risks to the lungs and cardiovascular system, reaching into the domain of accidental injury, which claims an enormous toll on young lives every year.

The scale of the problem is difficult to overstate. According to the study, nearly 39 percent of the adolescents surveyed reported having experienced at least one serious injury, defined through standardized questionnaires administered in school settings. The burden was not distributed evenly between the sexes: 45.60 percent of boys reported a serious injury compared with 33.32 percent of girls, a gap consistent with earlier research showing that boys tend to engage in more risk-taking behavior and are exposed more frequently to hazardous activities such as road traffic, sports, and physical violence. Global Burden of Disease analyses cited by the authors have repeatedly identified transport and unintentional injuries as dominant causes of mortality among people aged 10 to 24, making any modifiable risk factor for injury a priority target for public health intervention.

At the heart of the analysis was a straightforward but consequential question: are adolescents who use tobacco or substitute nicotine products, or who breathe other people’s smoke, more likely to suffer serious injuries than their unexposed peers? To answer it, the research team, led by Manman Chen and Zichen Ye of the Chinese Academy of Medical Sciences and Peking Union Medical College, applied multivariable logistic regression models to the pooled survey data. These statistical models allow investigators to estimate the association between an exposure and an outcome while adjusting for other variables that could confound the relationship. The primary analysis produced a clear signal. Adolescents who currently used tobacco or substitute products had roughly twice the odds of reporting a serious injury compared with non-users, with an odds ratio of 2.07 and a 95 percent confidence interval of 1.95 to 2.19.

Secondhand smoke told a similar story. Among adolescents who did not smoke themselves but were exposed to smoke in their environment, the odds of reporting a serious injury were 43 percent higher than among unexposed non-smokers, corresponding to an odds ratio of 1.43 with a confidence interval of 1.37 to 1.49. That a passive exposure, one the adolescents did not choose, was associated with injury risk is perhaps the most sobering element of the findings. It implies that the injury burden linked to tobacco extends into homes and communities where children cannot control their exposure, echoing a growing body of literature on the harms of secondhand exposure, including recent systematic reviews of secondhand exposure to e-cigarette aerosols.

The researchers then subjected their primary results to a series of robustness checks, and the picture that emerged was more nuanced than the headline numbers suggest. When the models were additionally adjusted for the year in which each survey was administered, the association for current tobacco and substitute use was attenuated, dropping from an odds ratio of 2.07 to 1.49, though it remained statistically significant with a confidence interval of 1.44 to 1.55. The estimate for secondhand smoke exposure, by contrast, was largely unchanged by the extra adjustment. This pattern indicates that some of the raw association between active use and injury may reflect temporal or cohort effects captured by survey year, but that a genuine residual association persists even after accounting for when the data were collected.

One of the most technically interesting aspects of the study is its treatment of ambient air pollution as a potential modifier of the tobacco-injury relationship. The authors stratified their analyses by country-level concentrations of fine particulate matter, or PM2.5, the microscopic airborne particles smaller than 2.5 micrometers that penetrate deep into the lungs and are implicated in oxidative stress and systemic inflammation. Prior research has linked long-term PM2.5 exposure to fall-related injuries in adults in low- and middle-income countries, and animal studies have shown that pollution-derived PM2.5 induces persistent oxidative stress and inflammation in lung tissue even after exposure ceases. The hypothesis underlying the stratification is that adolescents living in highly polluted environments may already carry a physiological load that interacts with tobacco smoke exposure, compounding its effects.

The stratified results offered partial support for that idea. Association estimates were slightly higher among girls than boys and slightly higher in countries with elevated PM2.5 levels, although most of these subgroup differences did not reach statistical significance. One exception stood out: among girls, the association between secondhand smoke exposure and serious injury was significantly stronger in the high-PM2.5 country group, with a P value for the subgroup difference below 0.001. This finding resonates with earlier evidence that females may be particularly vulnerable to some of the health effects of smoking, and it raises the possibility that the combination of polluted air and passive smoke exposure imposes a compounded burden on girls in the most contaminated environments. The authors are careful, however, to frame these as variations in the magnitude of associations rather than definitive evidence of biological interaction.

What mechanisms might connect tobacco exposure to injuries in the first place? The study, being cross-sectional, cannot establish causation, but the authors situate their findings within a rich mechanistic literature. Nicotine and tobacco smoke affect vascular function, cognition, and potentially attention and reaction time, any of which could plausibly increase the likelihood of accidents. Clinical research has shown that cigarette smoking increases complications following fractures and impairs bone healing, and cohort studies have documented that smoking cessation reduces fracture risk. There is also a behavioral pathway: adolescents who use tobacco are more likely to cluster with other risk behaviors, including alcohol use, violence, and reduced physical activity, a clustering phenomenon documented in analyses of hundreds of thousands of adolescents across 89 countries. Prior multi-country analyses have also shown that substance use among adolescents is associated with injuries partly through its mediating relationship with interpersonal violence.

The public health implications are considerable. If tobacco and substitute use roughly double the odds of serious injury among adolescents, then tobacco control measures, taxation, age restrictions, advertising bans, and school-based prevention programs, could deliver injury-reduction benefits that are rarely counted in their cost-effectiveness calculations. Likewise, the strong and stable association for secondhand smoke exposure underscores the value of smoke-free home and public space policies, particularly in low- and middle-income countries where the Global School-based Student Health Survey is concentrated and where regulatory protections are often weakest. Systematic reviews of interventions to prevent unintentional injuries in school-aged children have identified school-based education programs and environmental modifications as effective tools, and integrating tobacco prevention into these frameworks could multiply their impact.

As with any observational study, important caveats apply. The injury data are self-reported and may be subject to recall bias, the exposure measures rely on adolescent self-report of tobacco use and smoke exposure, and the cross-sectional design precludes any claim that tobacco use causes injuries rather than merely co-occurring with them. Residual confounding by factors such as alcohol use, socioeconomic status, and psychological distress cannot be excluded. Nevertheless, the sheer scale of the dataset, spanning 58 countries and more than 176,000 young people, lends the findings a weight that few single-country studies can match. The work was supported by the National Natural Science Foundation of China, and the authors report no competing interests. For parents, educators, and policymakers, the message is unambiguous: protecting adolescents from tobacco, both the smoke they inhale by choice and the smoke they breathe by circumstance, may be as much an injury-prevention strategy as a lung-health one, and in a world where nearly four in ten teenagers report being seriously hurt, every modifiable risk factor matters.

Subject of Research: Associations of adolescent tobacco use, substitute product use, and secondhand smoke exposure with serious injuries across 58 countries

Article Title: Tobacco and substitute use, secondhand smoke exposure, and serious injuries among adolescents: A multinational analysis of 58 countries

Article References: Chen, M., Ye, Z., Zhao, Y., Qu, Y., Wang, X., Wang, W., & Gu, M. (2026). Tobacco and substitute use, secondhand smoke exposure, and serious injuries among adolescents: A multinational analysis of 58 countries. Air Quality, Atmosphere & Health, 19(10), Article 223. https://doi.org/10.1007/s11869-026-02112-3

Image Credits: AI Generated

DOI: 10.1007/s11869-026-02112-3

Keywords: adolescent health, tobacco use, secondhand smoke, serious injuries, PM2.5, air pollution, Global School-based Student Health Survey, logistic regression, injury prevention, public health, nicotine, multinational study