Objective This study aims to investigate the impact of military service on tumor inci-dence within the population utilizing data from the NHANES database. Methods: A cross-sectional survey was conducted among individuals aged 18 years and older, as recorded in the NHANES database from 1999 to 2018. The primary outcome measure was the prevalence of self-reported cancer. Multivariate logistic regression analyses were employed to evaluate the association between military service, various covariates, and cancer prevalence. Results: The study included a total of 12,174 participants, of whom 1,904 (15.64%) reported a history of military service. Participants with a history of military service were, on average, older than those without such a history (66.17 ± 0.43 VS 52.79 ± 0.31). Additionally, individuals with military service were more frequently identified as white (85.45% vs. 69.74%, p < 0.001), exhibited higher rates of marriage and annual household income (p < 0.001), and were more likely to be smokers (66.01% vs. 43.32%, p < 0.001). In this study, the observed prevalence of cancer within the population was notably higher than that typically reported in the general population. This dis-crepancy is attributed to the exclusion of individuals who were unaware of their cancer status. The prevalence of cancer was particularly elevated among individuals with a history of military service, with rates of 76.95% compared to 46.87% (p < 0.001). Notably, cancers affecting the reproductive endocrine system, dermatological, skeletal, and other bodily systems were more frequently observed. After adjusting for all available con-founding variables, multivariate analyses revealed that the odds ratio (OR) for having a tumor in individuals without military service, compared to those with military service, was 0.26 (95% CI 0.23-0.30) and 0.40 (95% CI 0.31-0.53), respectively, indicating a signif-icantly reduced likelihood of tumor occurrence. Conclusion: Military service is associ-ated with an increased prevalence of tumors, particularly thyroid cancer. Further re-search is warranted to elucidate the relationship between military service and cancer diagnoses, as well as to identify the underlying causes of this association. Such efforts are essential for enhancing health protection measures for military personnel and re-ducing the incidence of cancer within this population.

The authors have declared no competing interest.

The author(s) received no specific funding for this work.

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