Mediating Factors in Secondhand Smoke and Atopic Dermatitis in Adolescents

Adolescents exposed to household secondhand tobacco smoke (SHS) face an increased risk of atopic dermatitis (AD), with a notable impact on girls. A recent study conducted at the Kuwait University College of Medicine in Safat, Kuwait aimed to unravel the mechanisms connecting household SHS exposure to AD among adolescents, identifying modifiable factors in the process.¹

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Methods

A cross-sectional study using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was conducted in 9 high schools in Hawalli, Kuwait. Data on sociodemographic characteristics, tobacco smoking, household SHS exposure, asthma, and atopic dermatitis were collected. Causal mediation analysis employed an inverse odds-weighting approach.²

Results

Among participants (n = 746), 54.1% had household SHS exposure, more prevalent among Kuwaiti (79.6%) than non-Kuwaiti (20.4%) adolescents. Self-reported asthma and AD prevalences were 20.6% and 14.9%, approximately. Household SHS exposure had a significant total effect (p = 0.043), with a non-significant natural direct effect (p = 0.133) and marginally insignificant natural indirect effect (p = 0.058). Asthma status and self-reported smoking jointly mediated the risk of AD by 29.6%.

Conclusion

This study revealed that adolescents' asthma and self-reported smoking not only directly influence AD risk but also mediate the effect of household SHS exposure. A smoke-free home rule emerges as a potential intervention to minimize SHS exposure, reduce asthma development, and discourage smoking initiation among adolescents.

The study adds to the limited literature on the relationship between household SHS exposure and AD among adolescents, particularly in Middle Eastern countries like Kuwait. The prevalence of household SHS exposure aligns with previous reports, emphasizing the urgent need for interventions. The novel aspect lies in the causal mediation analysis, shedding light on the interconnectedness of factors influencing AD.

The findings affirm the multifaceted impact of household SHS exposure on adolescents, extending beyond direct effects. The identification of asthma and self-reported smoking as mediators underscores the need for targeted interventions. A significant proportion of AD risk is mediated through these factors, emphasizing their role in shaping health outcomes.

Study Strengths and Limitations

The study's strengths included the use of the ISAAC questionnaire, providing standardized and reliable data. The inverse odds-weighting approach for causal mediation analysis enhances the robustness of the findings. Sensitivity analyses further validate the results, highlighting the study's methodological rigor.

However, some limitations warrant consideration. The cross-sectional design limits establishing causation, emphasizing the need for longitudinal studies. The reliance on self-reported data introduces potential recall bias, though efforts to minimize this were undertaken. Additionally, the study's focus on a specific region may affect generalizability, urging caution in applying findings to diverse populations.

Future Considerations

This study contributes valuable insights into the complex relationship between household SHS exposure and AD among adolescents. The identification of asthma and self-reported smoking as mediating factors emphasizes the interconnectedness of health outcomes. Dermatology clinicians can leverage these findings to advocate for holistic interventions that address both direct and mediated effects, fostering healthier environments for adolescents.

Moreover, the study advocated for a comprehensive approach to tackle AD among adolescents, including strategies to incorporate measures to reduce SHS exposure, prevent asthma development, and discourage smoking initiation.

References

1. Akhtar S, Al-Shanfari S, Booalayan H, et al. Exposure to household secondhand tobacco smoke and the odds of developing atopic dermatitis among adolescents: A causal mediation analysis. Tob Induc Dis. 2024;22:10.18332/tid/176967. Published 2024 Feb 1. doi:10.18332/tid/176967

2. Oliveira EF, Penedo C, Valle SOR, Kuschnir FC. Validation and reproducibility of the International Study of Asthma and Allergies in Childhood (ISAAC) Written Atopic Eczema Questionnaire for telephone survey in children aged 6-7 years. An Bras Dermatol. 2022;97(2):173-178. doi:10.1016/j.abd.2021.03.010