Husband smoking is associated with Wife's thyrotropin abnormality: A population-based cohort study among Chinese reproductive-aged women

Objectives: To comprehensively assess the association of husband smoking with wives' thyrotropin abnormality. Methods: This population -based retrospective cohort study included 2 406 090 Chinese reproductive -aged women who had participated twice in the National Free Pre -pregnancy Checkups Project between 2010 and 2020. Multivariate -adjusted odds ratios and 95% confidence intervals for subnormal and supranormal thyrotropin were estimated according to the husband's smoking status. Results: Husband smoking at the first visit was associated with a 17% (15%-20%) and 26% (24%-28%) increased odds of subnormal thyrotropin and supranormal thyrotropin respectively compared to participants in neithersmoker group. In non-smoking participants with normal thyrotropin levels at the first visit, the corresponding increased risk of subnormal thyrotropin and supranormal thyrotropin at the second visit were 15% (12%-18%) and 19% (16%-21%) in contrast to participants without husband -smoking exposure. In non-smoking participants with abnormal thyrotropin levels at their first visit, husband smoking cessation was associated with 27% (17%- 35%) and 36% (31%-40%) reduced odds of subnormal thyrotropin and supranormal thyrotropin at the second visit compared with the participants whose husband still smoking at the second visit. Conclusion: Husband smoking was associated with wives' subnormal thyrotropin and supranormal thyrotropin, and cessation of husband smoking could reduce the odds of thyrotropin abnormality. Couple -focused smoking intervention should be developed to reduce the burden of asymptomatic thyroid disease in females.