Background: Dysphagia is a common functional impairment in elderly populations, often leading to severe complications such as malnutrition and aspiration pneumonia, significantly increasing healthcare burdens. Currently, effective prognostic assessment tools are lacking. The absolute lymphocyte count (ALC), a biomarker reflecting immune-nutritional status, has potential predictive value in this context, though its role in dysphagia prognosis remains unclear. Methods: This retrospective cohort study included 253 dysphagic patients who received percutaneous endoscopic gastrostomy (PEG) or total parenteral nutrition (TPN) between 2014 and 2017. Five patients with missing ALC were excluded. Cox regression models assessed the association between ALC and mortality. ALC was analyzed as both continuous variable (using restriocted cubic splines) and categorical tertiles, with additional threshold analyses to assess non-linearity. Kaplan–Meier survival curves and subgroup analyses were also performed. Results: Lower ALC was associated with poorer nutritional status, higher inflammatory markers, and greater comorbidity burden. Higher ALC was independently associated with reduced mortality (adjusted HR: 0.60; 95% CI: 0.44–0.83; p = 0.002). Patients in the highest tertile had significantly better survival than those in the lowest (HR: 0.37; 95% CI: 0.23–0.59; P < 0.001). A non-linear threshold effect was identified at ALC = 1.899×10⁹/L (p for non-linearity = 0.009). Kaplan–Meier analysis confirmed improved survival with higher ALC (p < 0.0001). Subgroup analyses showed the protective effect of higher ALC was consistent across age, sex, BMI, PEG use, and comorbidity strata, with no significant interactions. Conclusions: ALC is an independent, non-linear predictor of mortality in older dysphagic patients and may aid clinical risk stratification across diverse patient subgroups.

This article presents a mathematical model designed to simulate the impact of targeted interventions aimed at preventing HIV transmission among female sex workers (FSWs) and their clients, while also analyzing their effects on the health of the general population. The compartmental model distinguishes between high-risk populations (FSWs and their clients) and low-risk populations (sexually active men and women in the general population), and links prevention efforts in high-risk groups to the evolution of the epidemic in the low-risk population. The fundamental properties of the model, such as the positivity of solutions and the boundedness of the system, have been verified, and the basic reproduction number R₀ has been calculated. Finally, the stability of the model was studied using Varga’s theorem and the Lyapunov method. Simulation results show that targeted prevention among FSWs and their clients reduces HIV incidence in the general population. This framework provides a valuable tool for guiding policymakers in the design of effective strategies to combat the epidemic, especially relevant in the context of suspension of USAID funding.

This study investigated adolescent students‟ knowledge of sexually transmitted infections (STIs) in eastern region schools for the deaf in Ghana. A descriptive survey design was used for the study. The researchers used HIV- The knowledge Questionnaire to assess the knowledge of respondents on STIs. Stratified sampling and simple random sampling techniques were employed. Proportional representation was used to select a sample of ninety-five (95) adolescent students with deafness from JHS2 and JHS3 between the ages of 13 and 24 years. Data were analyzed descriptively into frequencies and percentages. The results of the study indicated that the students knew of some of the types of STIs such as Gonorrhea, Syphilis, and HIV/AIDS. They, however, had inadequate knowledge of STIs such as Hepatitis B and Chlamydia.

Addressing adolescent and sexual reproductive healthcare is essential to providing young patients with the resources they need to navigate and empower themselves with. However, there is limited data about how often this occurs. Several studies have previously indicated that there is a large gap in accessing this gap in low-income neighborhoods. Our study aims to identify the establishment of gynecologic care among adolescent cisgender women and elucidate potential reasons for seeking or not seeking out care. We approached women in the pediatric emergency room that matched the inclusion criteria set out. Qualitative surveys were conducted until thematic saturation was reached and a cross-section study design was employed. Interviews were analyzed through modified ground theory. The study was conducted at the pediatric emergency department at University Hospital located in Newark, NJ. In 2018 estimates, the Newark population consists of 47.0% Black and 39.2% Hispanic or Latinos. Semi-structured interviews were conducted with 27 cisgendered, English-speaking females between ages 18 to 25 presenting to the pediatric emergency room who may or may not have previously established primary care with a gynecologist. Transcriptions were analyzed using modified grounded theory and themes were identified using inductive coding of patient interviews.

The principle of Undetectable = Untransmittable (U=U) posits that people living with the human immunodeficiency virus (HIV) who are able to achieve and maintain a viral load of <200 copies/mL by regularly taking antiretroviral drugs (ARVs) are considered virally suppressed and cannot transmit the HIV virus to other individuals through sex. This groundbreaking message has emerged as a key HIV prevention strategy for eliminating transmission risks and enhancing the quality of life of people living with HIV. This narrative review explores the clinical foundation of U=U, the level of awareness and acceptance of the message globally, and the psychosocial impact on people living with HIV. It has been discovered that this message minimizes stigma, improves mental health, promote treatment adherence and good disclosure behaviors among people living with HIV. Evidence has shown that despite the U=U revolution for HIV prevention, there are significant differences in awareness and acceptance of the message among different population groups. The challenges noted were poor communication by healthcare providers, limitations in the health system, and stigma issues. Nevertheless, the inclusion of U=U in mainstream HIV services has proven to increase awareness and enhance its adoption. The urgent need in the present review is to advocate for strategies to increase the equitable distribution of U=U to harness its full potential in public health.

Introduction: Stroke remains one of the leading causes of death and disability worldwide, with ischemic stroke accounting for most cases. Structural vascular factors such as carotid artery tortuosity have gained attention as potential markers of vascular aging and cerebrovascular risk. The carotid tortuosity index (CTI), defined as the ratio of actual vessel length to the straight-line distance between two fixed points, provides a quantitative measure of arterial curvature. A CTI value of ≥1.2 indicates pathological tortuosity. Although noninvasive modalities such as CTA and MRA are frequently used, digital subtraction angiography (DSA) remains the gold standard for evaluating vessel geometry due to its higher spatial precision. This study aimed to determine the association of age, sex, and hypertension with CTI measured by DSA. Methods: A cross-sectional study was conducted from November to December 2025 at the Neurointervention Clinic, RS Pelni Jakarta, Indonesia, involving 61 adult patients who underwent carotid DSA. CTI was measured bilaterally using digital imaging software and classified as <1.2 (non-tortuous) or ≥1.2 (tortuous). Clinical data, including age, sex, and hypertension status, were collected from medical records and analyzed using bivariate tests. Results: Older age (≥65 years), female sex, and hypertension were significantly associated with higher CTI values on both carotid sides. Tortuosity was more common among hypertensive patients and elderly females, indicating the influence of vascular remodeling and chronic hemodynamic stress. Conclusion: Carotid tortuosity increases with age, hypertension, and female sex. DSA-based CTI measurement provides a reliable and precise approach for evaluating vascular changes associated with cerebrovascular risk.

Background: Resting-state functional MRI (rsfMRI) provides insights into large-scale brain network organization associated with cognitive control, emotion regulation, and attentional processes. The ventral attention network (VAN) is a key salience-driven network that supports attentional re-orienting to behaviorally relevant stimuli. However, little is known about how VAN resting state functional connectivity varies by demographic, socioeconomic, psychosocial, and behavioral factors during early adolescence. Objective: To examine associations between VAN rsfMRI connectivity and multiple demographic, socioeconomic, psychosocial, and behavioral characteristics. Methods: Data came from the baseline and early follow-up waves of the Adolescent Brain Cognitive Development (ABCD) Study. The analytic sample included youth with high-quality baseline rsfMRI data and complete socioeconomic and psychosocial measures. The primary outcome was mean resting-state functional connectivity within the VAN across subcortical and cortical regions of interest (ROIs). Bivariate correlations were computed between VAN connectivity and demographic (age, sex, puberty, race/ethnicity), socioeconomic (income, parental education, marital status, neighborhood income), psychosocial (trauma, discrimination, financial difficulty), trait (impulsivity), and behavioral variables (body mass index, depression, suicide, prodromal symptoms, and substance use). Unadjusted bivariate correlations and adjusted logistic regressions were used for data analysis. Results: VAN connectivity showed small but significant correlations with multiple contextual factors. Higher household income, parental education, and neighborhood affluence were associated with greater connectivity, whereas Black race and Hispanic ethnicity were related to lower connectivity. Youth reporting higher discrimination and financial difficulty exhibited weaker VAN connectivity. Greater VAN connectivity was negatively associated with impulsive reward-driven trait (drive), prodromal symptoms, BMI, and marijuana and alcohol use. Associations between VAN connectivity and suicide, depression, marijuana use, and alcohol use remained significant in age and sex adjusted models. Conclusions: VAN connectivity reflects subtle neural correlates of socioeconomic and psychosocial context in early adolescence. Our results underscore the importance of integrating structural and contextual factors in interpreting brain-behavior associations across diverse populations. These findings are suggestive of stable socioeconomic and psychosocial correlates of network efficiency.

Background: Adolescence is a critical developmental stage for the emergence of major depressive disorder (MDD). Structural and diffusion neuroimaging studies have highlighted the anterior cingulate cortex (ACC) as a key region implicated in emotion regulation, stress reactivity, and mood processing. However, few studies have examined whether microstructural characteristics of the ACC, reflected by mean diffusivity (MD) within gray matter–white matter (GM–WM) contrast regions, are associated with depression in early adolescence. Objective: To examine whether mean diffusivity (MD) within the GM–WM contrast of the left caudal anterior cingulate cortex (ACC) is associated with a past diagnosis of MDD among adolescents in the Adolescent Brain Cognitive Development (ABCD) Study, after accounting for demographic, socioeconomic, and adversity-related factors. Methods: Data were drawn from adolescents with diffusion MRI–derived mean diffusivity measures and diagnostics. The independent variable was mean diffusivity (MD) of the GM–WM contrast in the left caudal ACC. The primary outcome was past MDD diagnosis based on structured psychiatric assessments. Covariates included age, sex, socioeconomic status (SES), and exposure to adverse childhood experiences (ACEs). Logistic regression models tested the association between ACC MD and past MDD. A secondary model evaluated the relationship between ACC MD and past suicide attempt. Results: Mean diffusivity of the left caudal ACC was associated with the odds of past MDD, independent of age, sex, SES, and adversity exposure. In contrast, ACC mean diffusivity was not associated with a history of suicide attempt. Conclusions: Increased mean diffusivity in the caudal ACC may indicate microstructural alterations associated with depressive vulnerability in adolescence. ACC tissue integrity may serve as a sensitive neural correlate of early-onset depression.

Background: Sexual and gender minority (SGM) youth are at elevated risk for adverse mental health and substance use outcomes. Stressors such as family conflict, discrimination, and trauma have been suggested as possible mediators of these disparities. Aims: This study examined whether family conflict, discrimination, and trauma mediate the associations between SGM identity and adverse outcomes, including suicide attempt, major depressive disorder (MDD), nicotine use, and marijuana use. Methods: Participants were children from the Adolescent Brain Cognitive Development (ABCD) study. SGM identity was reported at baseline, while outcomes included past MDD and suicide attempts as well as future nicotine and marijuana use. Structural equation modeling (SEM) was used to test both direct and indirect pathways linking SGM identity to mental health and behavioral outcomes. Results: No significant mediation was found through family conflict, discrimination, or trauma. Instead, effects of SGM identity were primarily direct: SGM youth had higher odds of past suicide attempts and MDD, as well as future marijuana use, but not future nicotine use. Stressor variables, however, were independently associated with outcomes. Discrimination predicted all outcomes; trauma was positively associated with suicide, nicotine, and marijuana use but not MDD; and family conflict predicted all outcomes except MDD. Conclusion: Family conflict, discrimination, and trauma did not mediate SGM disparities in mental health and substance use, but each emerged as an independent predictor of risk. These findings highlight the complexity of mechanisms underlying SGM-related disparities and suggest the need for future research to explore additional pathways and contextual influences.

This review article provides a comprehensive anatomical analysis of soccer footwear, delving into the intricate structure and functional roles of its constituent components, including the upper, heel counter, tongue, toe box, outsole/sole plate, studs, and insole. Manufacturing processes influencing these structural elements are also discussed. Current market offerings and patented innovations in soccer cleat technology are examined through a biomechanical lens, highlighting their intended functions and limitations. A critical synthesis of existing knowledge underscores the anatomical and biomechanical distinctions between male and female athletes' feet, arguing for the necessity of sex-specific footwear design. This review culminates in emphasizing the imperative for specifically engineered soccer footwear for female athletes to optimize performance, enhance comfort, and mitigate the elevated risk of lower extremity injuries prevalent in the female game, thereby identifying crucial directions for future research in sports biomechanics and footwear engineering.

Background: High educational attainment is a well-recognized protective factor against health problems such as diabetes. However, the theory of Minorities' Diminished Returns (MDRs) suggests that this protective effect is weaker for ethnic minorities compared to non-Latino Whites. This diminished effect is thought to result from structural inequalities, such as lower-quality education and fewer occupational opportunities, faced by ethnic minorities. Objective: This study examined the protective effect of years of schooling—used as a proxy for educational attainment—on diabetes mellitus (DM), overall and by ethnicity. Based on the MDRs framework, we hypothesized that the protective effect of education would be weaker for Latino individuals compared to non-Latinos. Methods: Data were drawn from the 2012 wave of the Understanding America Study (UAS), a nationally representative, internet-based panel. The outcome of interest was self-reported doctor diagnosis of DM. Logistic regression models were used to assess the association between educational attainment and DM, with an interaction term to explore differences between Latino and non-Latino individuals. Models were adjusted for age, sex, employment, immigration status, and marital status. Findings were presented as adjusted odds ratios (OR), p-values, and 95% confidence intervals (CIs). Results: Higher educational attainment was associated with lower odds of DM in both Latino and non-Latino individuals (p < 0.001). An interaction between education and ethnicity (p < 0.05) indicated that the protective effect of education was weaker for Latino individuals compared to non-Latinos. Conclusion: The findings align with the MDRs framework, which suggests that the health benefits of education are not equally distributed across ethnic groups. For Latino individuals, structural barriers such as lower educational quality and labor market discrimination may limit the protective effect of education against DM. While education is a key determinant of health, its unequal returns contribute to ethnic health disparities. Policymakers must address structural inequalities in education and employment that disproportionately affect ethnic minorities. Tackling these disparities through multi-sector policy interventions will require bipartisan political support.

Background: Epigenetic aging, measured through various DNA methylation-based clocks, may have implications for predicting disease risk. However, the sensitivity of different epigenetic clocks that have emerged as biomarkers for biological aging and in predicting physical and mental health outcomes remains uncertain. This study examines the age and sex-adjusted associations between multiple epigenetic age acceleration measures and three key health indicators, including self-rated health, depressive symptoms, and body mass index (BMI), in a nationally representative sample of U.S. middle-aged and older adults. Methods: We analyzed data from 4,018 adults in the 2016 wave of the Health and Retirement Study (HRS), which included several epigenetic age acceleration measures: HORVATH, HANNUM, LEVINE, HORVATHSKIN, LIN, WEIDNER, VIDALBRALO, YANG, ZHANG, BOCKLANDT, GARAGNANI, and GRIMAGE. Linear regression models were used to assess the associations between epigenetic age acceleration and self-rated health (poor health), depressive symptoms, and BMI, adjusting for age and sex. Results: We found significant positive associations between epigenetic age acceleration and worse self-rated health, higher depressive symptoms, and increased BMI. However, these associations varied across different epigenetic clocks, with some measures potentially having more consistent utility for specific health outcomes than others. Conclusion: Epigenetic age acceleration is linked to poorer self-rated health, greater depressive symptoms, and higher BMI, but choosing which epigenetic clock(s) to use is also important. These findings underscore the need to consider multiple epigenetic aging markers when assessing health risks and highlight the potential for particular clocks to serve as more sensitive indicators of physical and mental health outcomes.

Background: Electronic cigarette (e-cigarette) use and vaping tobacco have increased rapidly worldwide, raising concerns about their health effects, social acceptability, and regulatory challenges. In many countries, e-cigarettes are more commonly used by individuals from higher socioeconomic status (SES) backgrounds, who, in theory, should have greater knowledge about e-cigarettes and their associated risks. However, it remains unclear why a group with more knowledge about e-cigarette risks would also hold more positive attitudes toward vaping and exhibit higher usage rates — a phenomenon that may represent a knowledge-behavior paradox. Understanding this paradox, along with the complex relationships between e-cigarette knowledge, attitudes, and behaviors, is critical for informing effective public health interventions, campaigns, social media messaging, and regulatory policies. Objectives: This study aimed to evaluate the complex relationship between SES, e-cigarette knowledge, pro-vaping attitudes, and e-cigarette use. Methods: The SMOKES Study (Study of Measurement of Knowledge and Examination of Support for Tobacco Control Policies) used a multi-center, cross-sectional design, collecting data from 2,403 college and university students across 15 provinces in Iran (covering nearly half of the country's provinces). The survey measured family income, age, sex, ethnicity, e-cigarette use, knowledge, and attitudes. Structural Equation Modeling (SEM) was employed to examine the interrelations between SES, knowledge, attitudes, and behavior, while adjusting for age, sex, and ethnic minority status. Results: SEM analysis confirmed the hypothesized paradox. Although greater knowledge about e-cigarettes was linked to less favorable attitudes toward vaping and lower use, pro-vaping attitudes emerged as the strongest predictor of vaping behavior, while knowledge played a weaker protective role. Notably, individuals with higher SES simultaneously showed higher knowledge and, paradoxically, more pro-e-cigarette attitudes and greater usage. Female students and ethnic minority students reported higher correct knowledge and lower pro-vaping attitudes and use. Although age and higher family income were associated with more favorable attitudes, they did not directly predict vaping behavior. These results suggest that for higher SES individuals, poor knowledge is not the main driver of e-cigarette use; rather, their pro-e-cigarette attitudes, which seem to outweigh the influence of knowledge, play a key role. Conclusions: Although individuals from higher SES backgrounds report greater correct knowledge about e-cigarettes, this knowledge does not necessarily translate into reduced positive attitudes or lower usage. This study highlights the complexity of these paradoxical effects and suggests that public health strategies need to go beyond simple education and knowledge-based interventions. Targeted approaches should address industry messaging, challenge misconceptions, and strengthen regulatory efforts to reduce e-cigarette use among young adults, including those from higher SES backgrounds.

Background: The Cingulo-Opercular Network (CON) is a crucial executive control network involved in regulating actions and facilitating higher-order cognitive processes. Resting-state functional connectivity between the CON and the Default Mode Network (DMN) plays a vital role in cognitive regulation, enabling the transition between internally focused and externally directed tasks. This study investigates whether resting-state functional connectivity between the CON and DMN mediates the effects of social determinants, such as educational opportunities and family structure, on cognitive outcomes in youth. Aims: This study aims to explore how CON-DMN connectivity influences the relationship between social gradients and cognition in youth. Specifically, it examines whether resting-state functional connectivity between these networks mediates the effects of educational opportunities and family structure on cognitive outcomes and seeks to uncover the neural mechanisms underlying these social gradients. Methods: Data were derived from the Adolescent Brain Cognitive Development (ABCD) study, a large longitudinal dataset of over 11,000 children aged 9–10 years. Cognitive outcomes were assessed using standardized NIH toolbox measures: Total Composite, Fluid Reasoning, Picture Vocabulary, Pattern Recognition, and Card Sorting. Social determinants were operationalized using indicators such as parental education, family composition, and neighborhood educational opportunities (COI). Resting-state functional connectivity (rsFC) between the CON and DMN was measured using functional magnetic resonance imaging (fMRI). Structural equation modeling (SEM) was employed to test whether CON-DMN rsFC mediated the relationship between social determinants and cognitive outcomes, adjusting for potential confounders such as age, sex, and race/ethnicity. Results: Stable family structure and greater educational opportunities were significantly associated with improved cognitive performance. These relationships were mediated by reduced functional connectivity between the CON and DMN. Conclusion: Reduced functional connectivity between the CON and DMN serves as a neural mechanism linking social gradients, such as educational opportunities and family structure, to better cognitive outcomes in youth.

Background: Socioeconomic status (SES) is a well-established determinant of health, often associated with lower risk of cardiometabolic diseases (CMD). However, the extent to which SES influences CMD may vary by gender due to differences in social roles, health behaviors, and biological susceptibilities. This study examined the relationship between SES, measured by the poverty-to-income ratio (PIR), and CMD indicators—including obesity, diabetes, and cardiovascular disease (CVD)—among men and women using data from the National Health and Nutrition Examination Survey (NHANES). Methods: This cross-sectional study utilized NHANES data (1999-2018), adjusting for race/ethnicity and age. SES was operationalized using PIR, with CMD outcomes (obesity, diabetes, and CVD) as dependent variables. Generalized linear models (GLM) were employed to evaluate the main effects of SES on CMD, with gender included as a moderator. Results: Higher SES was associated with lower overall CMD risk. However, the protective effects of SES were more pronounced in women than in men for all outcomes. These findings suggest that gender-specific pathways may mediate the relationship between SES and CMD. Women may derive greater health benefits from higher SES due to factors such as reduced stress exposure, healthier behaviors, and increased healthcare utilization. Conversely, the weaker association observed in men may reflect differences in social hierarchy sensitivity, responses to unemployment, or other contextual factors. Conclusion: The findings highlight the importance of gender-specific considerations when addressing SES-related disparities in CMD outcomes. Policies and interventions aimed at reducing CMD burden should account for these gender differences to promote equitable improvements in cardiometabolic health. Further research is needed to unravel the mechanisms driving these differences and to inform targeted strategies.

Background: Socioeconomic status (SES) is a well-established predictor of cognitive function in children, but the neurobiological pathways through which SES influences cognitive outcomes remain underexplored. This study examines the role of the cingulate gyrus (region of the brain that is involved in emotion regulation, decision-making, error detection, and cognitive control) in mediating the relationship between SES and cognitive performance, with a focus on whether these effects vary by sex. Objective: To investigate the role of the cingulate gyrus in mediating the association between social gradients (family SES) and cognitive function in children and assess potential sex differences in these pathways. Methods: Data were drawn from the Adolescent Brain Cognitive Development (ABCD) study. Cognitive function was assessed using a composite measure of executive function and general cognitive ability. Structural MRI data were used to measure the volume of the cingulate gyrus. Path analysis was conducted to examine the mediating role of the cingulate gyrus in the association between SES and cognitive function. Interaction terms were included to test for sex differences. Results: Higher SES was significantly associated with a larger cingulate gyrus volume and better cognitive function. The volume of the left cingulate gyrus partially mediated the relationship between family and neighborhood SES and cognitive function, explaining a portion of the social gradient in cognitive outcomes. No significant sex differences were found in these mediating effects. Conclusions: The cingulate gyrus partially mediates the link between SES and cognitive function in children. These findings suggest that social disparities in cognitive function may operate, in part, through neurobiological changes such as those in the cingulate gyrus, without significant variation by sex.

Objective: This study investigates the pathways linking socioeconomic status (SES), trauma, early puberty, and tobacco use, with a focus on how these relationships differ by sex. Using data from the Adolescent Brain Cognitive Development (ABCD) study, we explore how SES and race contribute to trauma exposure, which in turn may influence early puberty and tobacco use. The study also examines potential mediating effects of trauma and early puberty on the association between SES and tobacco use, while comparing these pathways for males and females. Methods: Data were drawn from the ABCD study, and structural equation modeling (SEM) was employed to test direct and indirect pathways between SES, trauma, early puberty, and tobacco use. The sample was stratified by sex to assess differences in these relationships for males and females. Key predictors included SES, race, and age, while outcomes were trauma, early puberty, and tobacco use. The model assessed mediating effects of trauma and early puberty on tobacco use. Results: Trauma was a significant predictor of early puberty for females (B = 0.032, SE = 0.015, p = 0.039) but not males. Early puberty was significantly linked to tobacco use for females (B = 0.048, SE = 0.015, p = 0.001) but not for males. Additionally, trauma had an effect on tobacco use among females (B = 0.048, SE = 0.014, p < 0.001) but not males. Lower SES was significantly associated with higher trauma exposure for both males (B = -0.109, SE = 0.014, p < 0.001) and females (B = -0.110, SE = 0.015, p < 0.001). Conclusions: The findings suggest that trauma and early puberty play more significant roles in the pathways from SES to tobacco use for females than for males. While trauma and early puberty are crucial mediators for females, these factors are less predictive for males. These results highlight the importance of sex-specific interventions targeting trauma and early puberty as pathways to early tobacco use.

Background: Climate change has raised significant concerns about its impact on health, particularly for vulnerable populations such as children and adolescents. While extensive research has examined physical health effects, limited attention has been given to the influence of extreme heat on developmental and behavioral outcomes. Objectives: This study investigates the association between extreme heat exposure and early puberty initiation (ages 9-10), using data from the Adolescent Brain Cognitive Development (ABCD) study. It further explores how early puberty correlates with behavioral problems and tobacco use initiation. Methods: Data from 11,878 participants in the ABCD study were analyzed to examine the relationship between extreme heat exposure (independent variable) and puberty initiation (outcome). Behavioral problems and tobacco use initiation were evaluated as downstream outcomes of early puberty. Covariates included age, sex, and race/ethnicity, and behavioral problems were assessed using the Child Behavior Checklist (CBCL). Structural equation modeling (SEM) was employed for analysis. Results: Extreme heat exposure was significantly associated with earlier puberty initiation at ages 9-10. Early puberty, in turn, correlated with higher levels of behavioral problems and an increased likelihood of tobacco use initiation. Conclusions: These findings underscore the importance of addressing environmental factors such as extreme heat to reduce risks associated with early maturation, including behavioral and substance use challenges. Targeted interventions and policies are needed to mitigate the impact of extreme heat on child development, and longitudinal studies are essential to confirm these results and inform effective prevention strategies.

Background: The rising concerns surrounding climate change have drawn attention to its potential impact on health, particularly among vulnerable groups such as children and older adults. Despite extensive research on health consequences, limited studies have explored the connection between extreme heat exposure and tobacco use initiation among adolescents in the United States. Objectives: This study examines the relationship between extreme heat exposure and the initiation of tobacco use in adolescents, using data from the Adolescent Brain Cognitive Development (ABCD) study. It also evaluates the mediating roles of major depressive disorder (MDD) and childhood behavioral problems. Methods: Data from 11,878 participants in the ABCD study were analyzed to explore the link between extreme heat exposure (independent variable) and tobacco use initiation (dependent variable). Covariates included age, sex, and race/ethnicity, while MDD and behavioral problems (measured using the Child Behavior Checklist, CBCL) were assessed as potential mediators. Structural equation modeling (SEM) was applied for analysis. Results: The findings indicated a significant association between extreme heat exposure and an increased likelihood of tobacco use initiation in adolescents aged 9 to 15. MDD and behavioral problems partially mediated this relationship. Conclusions: These results underscore the importance of targeted interventions aimed at mitigating the impact of extreme heat on adolescent health, including its influence on tobacco use initiation. Addressing mental health and behavioral challenges could help reduce these risks. Future longitudinal research is needed to confirm these findings and evaluate the efficacy of strategies to protect vulnerable youth populations.