The research, conducted by Jinwook Yang, Daesung Lee, and Kyenghee Kwon of Dongguk University, drew on data from the 2023 and 2024 Korea National Health and Nutrition Examination Survey, known as KNHANES. This ongoing national survey, run by the Korea Disease Control and Prevention Agency, combines health interviews, physical examinations, and laboratory measurements to build a representative picture of the Korean population. From it, the researchers assembled an analytic sample of 11,346 adults aged 19 years or older, a size large enough to detect meaningful differences across tobacco use patterns while controlling for a wide range of demographic and health-related factors.

Health literacy, the central variable of the study, refers to a person’s capacity to obtain, understand, and apply health information in everyday decisions. The researchers measured it using a ten-item self-reported instrument, with total scores of 30 or higher classified as adequate. Respondents falling below that threshold were considered to have inadequate health literacy. This kind of measurement matters because health literacy is not simply a proxy for education; it captures how well people navigate medication labels, prevention messages, and the increasingly crowded information environment surrounding newer nicotine products, where marketing claims about reduced harm can be difficult for consumers to evaluate.

To characterize tobacco use, the team classified participants into three categories: non-current users, single-product users, and multiple-product users, based on their current use of conventional cigarettes, heated tobacco products, and electronic cigarettes. They also examined two cessation behaviors: whether a participant had attempted to quit within the past year, and whether they intended to quit within the next six months. This dual focus is notable, because much of the existing literature treats smoking as a single behavior, whereas the modern nicotine market allows consumers to combine products in ways that may carry distinct risks and may respond differently to public health messaging.

The statistical approach reflected the complexity of the survey design. Because KNHANES uses a stratified, multistage sampling framework, the researchers employed complex sample multinomial and binomial logistic regression analyses, adjusting for sex, age, educational attainment, household income, survey year, perceived stress, weight status, and chronic disease status. Multinomial models were used to compare single-product and multiple-product users against non-current users, yielding relative risk ratios, while binomial models assessed the cessation outcomes. Sensitivity analyses were then conducted to test whether the findings held up under alternative assumptions, and they did, strengthening the credibility of the central results.

The headline finding is striking in its clarity. Inadequate health literacy was associated with a 24 percent higher relative likelihood of single-product tobacco use compared with non-current use, with a relative risk ratio of 1.24 and a 95 percent confidence interval of 1.09 to 1.42. The association was even stronger for multiple-product use, where the relative risk ratio rose to 1.43, with a confidence interval of 1.13 to 1.82. In practical terms, adults who struggle to understand health information were not only more likely to smoke at all; they were disproportionately likely to be layering cigarettes, heated tobacco, and e-cigarettes together, a pattern that public health experts generally view as particularly concerning because it can sustain or even deepen nicotine dependence.

Just as revealing is what the study did not find. Health literacy showed no significant association with either past-year quit attempts or the intention to quit within six months. In other words, people with lower health literacy were more likely to use tobacco, but once they were users, their motivation to quit appeared similar to that of their more literate peers. The authors interpret this as evidence that the role of health literacy differs across tobacco-related outcomes: it may shape who enters and remains in the pool of tobacco users, yet it does not by itself determine whether those users try to break free. That distinction carries real weight for policy, because it suggests the problem lies less in motivation than in the upstream conditions that foster tobacco use in the first place.

Why would limited health literacy push people toward tobacco, and toward product combinations in particular? The authors point to the mechanics of health communication. Anti-smoking campaigns, warning labels, and cessation resources all presuppose an ability to read, interpret, and act on health information. When that ability is compromised, the persuasive and protective functions of such messaging weaken. Meanwhile, newer products such as heated tobacco devices and e-cigarettes are often marketed with technical language and claims of reduced harm that require a degree of health literacy to critically assess. Consumers with inadequate literacy may be more vulnerable to such claims, and the proliferation of flavored and technologically styled devices may lower the perceived barriers to experimentation, eventually culminating in the use of several products simultaneously.

The Korean context sharpens the significance of these results. Despite decades of successful tobacco control, the decline in smoking has recently stalled, and the market share of heated tobacco products and electronic cigarettes has grown rapidly, particularly among younger adults. At the same time, a substantial proportion of Korean adults report inadequate health literacy. The convergence of these trends creates a potential feedback loop in which the populations least equipped to evaluate health information are the most exposed to a diversifying nicotine market. Because the study is cross-sectional, it cannot establish causation; it is possible that tobacco use itself, or the conditions that lead to it, also degrade health-related understanding. Still, the robustness of the associations across sensitivity analyses, and the careful adjustment for education and income, make a compelling case that health literacy is an independent marker of tobacco-related risk.

The authors conclude that tailoring tobacco-related health communication to different health literacy levels, combined with comprehensive cessation support, may contribute to more effective tobacco control. In practice, that could mean simplifying warning labels and cessation materials, deploying visual and verbal channels that do not depend on high reading proficiency, and ensuring that quitline and counseling services are accessible and comprehensible to everyone. The finding that quit intentions are not lower among those with inadequate literacy is, in a sense, encouraging: the desire to quit appears broadly shared, and the task for public health is to build an information environment and support system that meets people where they are. As nicotine products multiply and evolve, the study suggests that the fight against tobacco will increasingly be won or lost not only through taxation and regulation, but through the clarity of the messages that reach the people who need them most.

Subject of Research: The association between health literacy, tobacco use patterns, and cessation behaviors among Korean adults

Article Title: Association between health literacy, tobacco use patterns, and cessation behaviors among Korean adults: a population-based cross-sectional study

Article References: Yang, J., Lee, D., & Kwon, K. (2026). Association between health literacy, tobacco use patterns, and cessation behaviors among Korean adults: a population-based cross-sectional study. BMC Public Health. https://doi.org/10.1186/s12889-026-29786-9

Image Credits: AI Generated

DOI: 10.1186/s12889-026-29786-9

Keywords: health literacy, tobacco use, smoking cessation, electronic cigarettes, heated tobacco products, multiple-product use, KNHANES, South Korea, public health, health communication, cross-sectional study, BMC Public Health

The headline numbers reveal a striking asymmetry between absolute scale and population-adjusted rates. In 2023, China recorded approximately 103,000 pancreatic cancer cases, substantially more than the 66,000 cases documented in the United States. Yet when the researchers adjusted for age structure, the picture inverted: China’s age-standardized prevalence stood at 4.51 per 100,000 people, compared with 11.19 in the United States, and its age-standardized mortality rate was 4.97 per 100,000 against 9.56 in the American population. This contrast reflects the interplay of population size, demographic aging, and underlying exposure to risk factors, and it underscores why raw case counts alone can mislead when comparing disease burden across countries with very different demographic profiles.

Trends over time added further nuance to the comparison. Between 1990 and 2023, the absolute burden of pancreatic cancer grew in both countries, a trajectory shaped by aging populations, population growth, and shifting exposures to known and suspected risk factors. However, when the researchers examined age-standardized DALYs, a metric that corrects for changes in population size and age composition, they found that China experienced a slight decline of 0.15 percent, while the United States saw a modest increase of 0.12 percent. Though these percentage changes appear small, they point in opposite directions and suggest that the two nations may be traveling along different epidemiological paths, with China potentially benefiting from earlier stages of its demographic and lifestyle transition and the United States confronting the cumulative consequences of metabolic disease.

Age distribution emerged as another point of divergence. In China, the burden of pancreatic cancer peaked among people aged 60 to 74, whereas in the United States the peak had shifted to an older bracket, ages 70 to 84. This difference in age patterning has practical consequences for health systems. It means that in China, pancreatic cancer strikes a working-age and recently retired population, amplifying the socioeconomic cost of each case through lost productivity and years of life lost, while in the United States the disease increasingly concentrates among the very old, placing demands on geriatric oncology services, palliative care infrastructure, and long-term support systems for elderly patients and their families.

Perhaps the most consequential finding of the study concerns the changing hierarchy of modifiable risk factors. In the United States, high fasting plasma glucose has overtaken tobacco use as the leading attributable risk factor for pancreatic cancer DALYs. In China, high fasting glucose has risen to become a major contributor, now roughly comparable to tobacco in its population-attributable impact. The researchers measured this using population attributable fractions, or PAFs, which quantify the proportion of disease burden that could theoretically be eliminated if a specific risk factor were removed at the population level. The ascent of metabolic risk factors in both countries signals a fundamental shift in the prevention landscape, one that moves pancreatic cancer control increasingly into the domain of diabetes management, obesity prevention, and metabolic health.

This shift is biologically plausible and fits within a broader scientific understanding of pancreatic carcinogenesis. Chronic hyperglycemia, insulin resistance, and type 2 diabetes have been repeatedly associated with elevated pancreatic cancer risk in epidemiological studies, and the pancreas is an organ exquisitely sensitive to metabolic stress. At the same time, the decline of tobacco as the dominant attributable factor in the United States reflects decades of successful smoking control, a public health achievement that has reduced smoking prevalence substantially since the 1960s. The Chinese trajectory differs: smoking remains widespread, particularly among men, so tobacco continues to exert a heavy toll even as metabolic risk factors rise rapidly alongside economic development, dietary change, and increasing rates of overweight and diabetes.

The study also examined the socioeconomic dimensions of pancreatic cancer burden, and here the findings were sobering. Globally, the burden of the disease remained concentrated in regions with a high socio-demographic index, a composite measure of income, education, and fertility that serves as a proxy for overall development. More troubling still, absolute socioeconomic inequality in pancreatic cancer burden increased over the study period. This pattern suggests that as some populations gain access to better diagnostics, registration, and care, the measured and actual burden accumulates disproportionately among wealthier and more developed settings, while gaps between the best-off and worst-off regions widen rather than narrow. For a disease that is already difficult to diagnose early and harder still to treat, such inequities compound the challenge of mounting an effective global response.

The methodological backbone of the analysis deserves attention, because it illustrates how modern burden-of-disease research works. The Global Burden of Disease Study synthesizes data from vital registration systems, cancer registries, and modeling approaches to produce comparable estimates across countries and years, complete with 95 percent uncertainty intervals that convey the precision of each figure. By combining these estimates with population attributable fractions for individual risk factors, the researchers could rank the drivers of pancreatic cancer DALYs in each country and track how those rankings changed between 1990 and 2023. This framework transforms raw epidemiological surveillance into actionable intelligence, allowing policymakers to see not just how much disease exists but which modifiable exposures contribute most to it and how those contributions are evolving.

The research was led by investigators including Dr. Yifei Hu of the School of Public Health at Capital Medical University in Beijing and Dr. Wenming Wu of the Department of General Surgery at Peking Union Medical College Hospital, and it was funded by the Beijing Natural Science Foundation and the National Natural Science Foundation of China. The authors conclude that tailored, country-specific prevention strategies will be essential to curb the growing burden of pancreatic cancer in the coming decades, with particular emphasis on addressing the rising tide of metabolic risk factors. For the United States, that means treating glycemic control and diabetes prevention as cancer prevention, while for China it demands a dual strategy that confronts both the entrenched tobacco epidemic and the accelerating metabolic transition simultaneously.

The broader lesson of this study extends beyond two countries. Pancreatic cancer is projected to remain a leading cause of cancer death worldwide, and its resistance to early detection and treatment makes prevention the most powerful available lever. As populations age and metabolic diseases proliferate across the globe, the findings from China and the United States offer a preview of what many nations may face: a rising tide of pancreatic cancer whose risk profile is shifting from behavioral exposures like smoking toward metabolic conditions like hyperglycemia. Health systems that anticipate this shift, investing in diabetes prevention, metabolic screening, and equitable access to care, may be better positioned to blunt the impact of one of medicine’s deadliest diseases before its burden becomes unmanageable.

Subject of Research: Comparative burden and risk factors of pancreatic cancer in China and the United States, 1990–2023

Article Title: Pancreatic cancer burden rises in both China and the US, but patterns diverge

Article References: Pancreatic cancer burden rises in both China and the US, but patterns diverge. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: pancreatic cancer, Global Burden of Disease, DALYs, high fasting glucose, tobacco use, China, United States, population attributable fraction, metabolic risk factors, age-standardized mortality, socioeconomic inequality, cancer prevention

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

The study, led by David A. Stupplebeen of the University of Hawaiʻi at Mānoa, with Candice D. Donaldson and Tam D. Vuong of the California Department of Public Health and UC Davis Comprehensive Cancer Center, drew on pooled data from the 2022 and 2023 cycles of the Online California Adult Tobacco Survey. That survey is designed to be representative of California adults, and the researchers restricted their analysis to people between the ages of 18 and 64, yielding a weighted analytic sample of 10,332 respondents. Because the data were weighted, the findings are intended to reflect the broader adult population of the state rather than just the people who happened to answer the questionnaire.

What sets this investigation apart is its measurement strategy. Rather than simply recording whether respondents belonged to a racial or ethnic minority group or identified as sexual or gender minorities, the researchers measured discrimination directly using the Everyday Discrimination Scale, a widely used instrument that asks about routine experiences of being treated with less courtesy or respect, being insulted, or being perceived as less capable. Respondents were then classified into categories based on the type of discrimination they attributed their experiences to: none at all, discrimination related to something other than race or sexual orientation, racial or ethnic discrimination only, sexual orientation discrimination only, or the joint experience of both racial-ethnic and sexual orientation discrimination.

The researchers also captured a dimension that is often overlooked in health disparities research: frequency. Experiencing discrimination once is not the same as living with it as a chronic, repeating feature of daily life. By standardizing discrimination scores and modeling both the type and the reported frequency of discriminatory experiences, the team could ask whether the chronicity of mistreatment mattered independently of its kind. The answer, according to their statistical models, was yes, and the patterns were strikingly different across categories.

The core results come from logistic regression models that adjusted for a range of demographic and socioeconomic factors, allowing the researchers to isolate the association between discrimination and tobacco use from confounders such as age, income, education, and other characteristics. Compared with adults who reported no discrimination, those who experienced discrimination tied to other reasons had 32 percent higher odds of current cigarette use, with an adjusted odds ratio of 1.32 and a 95 percent confidence interval of 1.11 to 1.57. Those who experienced sexual orientation discrimination alone faced roughly double the odds of smoking, with an adjusted odds ratio of 2.05 and a confidence interval of 1.47 to 2.85, the single largest effect observed in the study.

Perhaps the most counterintuitive finding involved people who reported experiencing both racial-ethnic and sexual orientation discrimination. Their adjusted odds of smoking were elevated, at 1.26 with a confidence interval of 1.10 to 1.45, but the effect was smaller than for sexual orientation discrimination alone. The same held true for vaping: joint discrimination was associated with 31 percent higher odds of current vaping, while racial-ethnic discrimination alone carried 53 percent higher odds and other discrimination 37 percent higher odds. The researchers interpret this not as evidence that intersectional discrimination is somehow protective, but as a reminder that the relationship between layered prejudice and health behavior is not a simple additive one, where each additional form of discrimination mechanically stacks risk on top of risk.

Across both outcomes, the direction of association was consistent: more discrimination, and more frequent discrimination, went together with higher odds of tobacco product use. For vaping, the adjusted odds ratios were 1.37 for other discrimination, 1.53 for racial-ethnic discrimination only, and 1.31 for joint discrimination, all with confidence intervals that excluded the null value of 1.0. The consistency of the positive association across two distinct tobacco products, one a combustible product with a century of epidemiological baggage and the other a relatively recent phenomenon, suggests that the underlying mechanism is not specific to any single delivery device but may relate to how people cope with chronic social stress.

The biological plausibility for such a link comes from a substantial body of research on minority stress and allostatic load. Chronic exposure to discriminatory treatment is thought to activate the body’s stress response systems repeatedly, elevating cortisol and sympathetic nervous system activity over time. Tobacco use, in this framework, can function as both a pharmacological coping mechanism, delivering nicotine that temporarily blunts negative affect, and a behavior embedded in social environments where stress and marketing pressure converge. The California findings cannot prove causation, since the data are cross-sectional and discrimination and tobacco use were measured at the same time, but they add to a growing pattern of evidence that perceived discrimination behaves like a modifiable risk factor for one of the world’s leading causes of preventable death.

The methodological implications may be as important as the substantive ones. Public health surveillance has long relied on demographic categories, race, ethnicity, sexual orientation, gender identity, to identify populations at elevated risk. Those categories are useful but blunt, and they describe characteristics that are immutable. By measuring the actual experience of discrimination, including its type and its frequency, the study demonstrates a way to identify risk that tracks something potentially changeable. If discrimination contributes to tobacco use, then reducing discrimination, through policy, enforcement, or community intervention, becomes a legitimate tobacco control strategy, not merely a matter of social justice pursued for its own sake.

The authors are careful about the limits of their work. The study is observational, the discrimination measures rely on self-report, and the attribution of discriminatory treatment to a specific cause, race versus sexual orientation versus something else, is inherently subjective. The analysis was also restricted to California adults of working age, and patterns could differ elsewhere. Still, the study, which was funded in part by the California Department of Public Health and reviewed as exempt by the University of Hawaiʻi at Mānoa Institutional Review Board, offers a template for future research: model discrimination as an exposure with both a type and a chronicity, rather than as a proxy embedded in demographic labels. If replicated, the finding that sexual orientation discrimination alone roughly doubles the odds of cigarette smoking would rank among the strongest social-environmental correlates of tobacco use ever quantified at the population level, and it would give tobacco control programs a concrete, measurable target in their efforts to close the gaps in health that demographics alone cannot explain.

Subject of Research: The association between racial/ethnic and sexual orientation discrimination and tobacco product use among California adults

Article Title: Tobacco product use at the intersection of racial/ethnic and sexual orientation discrimination among California adults, 2022–2023: an observational study

Article References: Stupplebeen, D. A., Donaldson, C. D., & Vuong, T. D. (2026). Tobacco product use at the intersection of racial/ethnic and sexual orientation discrimination among California adults, 2022–2023: an observational study. International Journal for Equity in Health. https://doi.org/10.1186/s12939-026-03054-z

Image Credits: AI Generated

DOI: 10.1186/s12939-026-03054-z

Keywords: tobacco use, discrimination, health disparities, sexual orientation, race and ethnicity, cigarette smoking, vaping, minority stress, California, epidemiology, public health, equity

The default mode network has occupied a central place in cognitive neuroscience since its discovery in the early 2000s, when positron emission tomography and, later, functional magnetic resonance imaging revealed a set of regions that consistently decrease their activity during demanding external tasks and increase it during quiet rest. This network, anchored in the medial prefrontal cortex, the posterior cingulate cortex, the precuneus, and the inferior parietal lobule, is thought to support autobiographical memory retrieval, envisioning the future, self-referential processing, and mind-wandering. In schizophrenia, decades of imaging work have documented disruptions in this network’s connectivity, which have been linked to disturbances in self-monitoring, hallucination severity, and disorganized thought. What the new study adds is a bridge between this circuitry and one of the most consequential health behaviors in the disorder: smoking.

The researchers approached the question using resting-state functional connectivity analysis, a technique that measures the degree to which spatially distributed brain regions fluctuate together in their blood-oxygen-level-dependent signals while participants lie quietly in the scanner. Synchronized low-frequency fluctuations are interpreted as a signature of functional coupling, even though they do not directly measure anatomical wiring. By parcellating the cortex and extracting connectivity profiles associated with the default mode network, the team was able to quantify how strongly parietal nodes of this circuit communicated with the rest of the network and with other major systems, including the frontoparietal control network and the salience network, which are implicated in cognitive control and in switching between internal and external attention.

Across the study sample, the strength of parietal default mode connectivity emerged as a statistically reliable correlate of tobacco use measures, which for many participants included biologically verified indicators such as cotinine levels, the primary metabolite of nicotine, rather than relying solely on self-report. This methodological point matters enormously. Self-reported smoking in psychiatric populations is notoriously unreliable, shaped by stigma, recall difficulty, and cognitive impairment, and studies that depend on it risk both overestimation and underestimation of true exposure. By anchoring the smoking phenotype in objective biochemical measures where available, the analysis strengthens the claim that the brain-behavior association is genuine rather than an artifact of reporting bias.

Why should a network associated with daydreaming and self-referential thought care about nicotine? One plausible explanation lies in the interplay between the default mode network and dopaminergic signaling. Nicotine acts on nicotinic acetylcholine receptors that modulate dopamine release in the mesolimbic pathway, the reward circuitry that reinforces drug-taking. In psychosis, this dopaminergic system is already dysregulated, with the prevailing neurobiological models of schizophrenia positing aberrant striatal dopamine synthesis and release as a proximate cause of positive symptoms. Nicotine’s ability to transiently normalize aspects of this signaling, or to dampen sensory gating deficits, has long been cited in self-medication accounts. The new findings suggest that individual differences in the intrinsic organization of the default mode network may reflect, or even partly determine, the degree to which nicotine exerts reinforcing and normalizing effects in a given brain.

A complementary interpretation comes from the cognitive domain. The default mode network and the frontoparietal control network are engaged in a dynamic antagonist relationship: when the former is active, the latter is typically suppressed, and effective cognitive performance requires the orchestration of switching between internally and externally directed states. Smoking initiation and maintenance depend on executive functions, including the capacity to inhibit impulses, delay gratification, and weigh long-term health consequences against immediate relief. If parietal default mode connectivity indexes the rigidity of internal focus or the difficulty of disengaging from internally generated thought, then individuals with stronger or atypical coupling may find external, health-protective control processes harder to deploy, making tobacco use more likely to persist. In this framing, connectivity is not a cause of smoking in a simple causal chain but a marker of the neurocognitive soil in which the behavior takes root.

The psychosis context amplifies both the scientific and clinical significance of these results. Roughly three-quarters of people with schizophrenia who smoke do so heavily, and smoking accounts for the majority of the excess mortality observed in the disorder. Yet smokers with psychosis are less likely to receive smoking cessation counseling, less likely to be prescribed pharmacotherapy such as varenicline or bupropion, and more likely to relapse after quitting attempts. If neural measures such as default mode connectivity could stratify patients by the likely neurobiological drivers of their smoking, clinicians might eventually tailor interventions accordingly, deploying more intensive combined behavioral and pharmacological strategies for those whose circuit profiles indicate a strongly entrenched pattern. The present study does not yet support such clinical deployment, but it supplies the kind of mechanistic correlate that personalized approaches require.

As with all resting-state connectivity research, important caveats frame the interpretation. Functional connectivity is correlational; the cross-sectional design of the analysis cannot determine whether atypical parietal connectivity predisposes individuals to smoking, whether chronic nicotine exposure reshapes the network over time, or whether both are downstream of a third factor such as illness severity, medication exposure, or shared genetic risk. Longitudinal designs, within-person repeated imaging, and causal modeling techniques, including studies in animal models where nicotine exposure can be experimentally controlled, will be needed to disentangle these possibilities. Sample heterogeneity, medication effects, and the modest effect sizes typical of brain-wide association studies further caution against overreading any single result. Still, the consistency of the default mode network’s involvement across cognitive, symptomatic, and now behavioral domains in psychosis builds a cumulative case that this circuit is a genuine hub of individual difference in the disorder.

For the broader field, the study exemplifies a trend in psychiatric neuroscience toward connecting large-scale intrinsic brain organization with real-world health behaviors, rather than with abstract laboratory measures alone. Smoking is among the most modifiable risk factors in severe mental illness, and understanding its neural correlates is a step toward interventions that could meaningfully extend lives. The finding that the brain’s daydreaming circuitry carries information about tobacco use in psychosis is a reminder that even the most habitual and seemingly volitional behaviors are embedded in the biology of the disorders themselves, and that dismantling smoking’s grip on this vulnerable population may ultimately require working with, rather than around, the architecture of the psychotic brain.

Subject of Research: Resting-state parietal default mode network functional connectivity and its association with tobacco use in psychotic disorders

Article Title: Parietal default mode network connectivity is associated with tobacco use in psychosis

Article References: Parietal default mode network connectivity is associated with tobacco use in psychosis. (n.d.). https://doi.org/10.1038/s41537-026-00797-0

Image Credits: AI Generated

DOI: 10.1038/s41537-026-00797-0

Keywords: schizophrenia, psychosis, default mode network, tobacco use, nicotine, functional connectivity, resting-state fMRI, neuroimaging, dopamine, smoking cessation, parietal cortex, severe mental illness