Negative association between asthma and tuberculosis: The mediating effect of albumin

Objective This study aimed to assess the relationship between asthma and tuberculosis (TB) risk and to explore whether oxidative stress-related serum markers available in National Health and Nutrition Examination Survey (NHANES) mediate this association.Methods Data were obtained from NHANES. Multivariate logistic regression was used to examine the association between asthma and TB and between oxidative stress-related serum markers and TB. Generalized linear regression was used to analyze the association between asthma and oxidative stress-related serum markers. Mediation analysis was used to evaluate the role of albumin, as the only marker that remained significant, in the association between asthma and TB. A core propensity score matching (PSM) sensitivity analysis was performed.Results Asthma was associated with TB risk in 3 different models (all odds ration [OR] < 1, all P < 0.05). Among oxidative stress indicators, only albumin concentration was associated with TB risk, and higher albumin concentrations were associated with lower TB risk (all P < 0.05). Furthermore, asthma was associated with albumin concentration in 3 models (all β < 0, all P < 0.05). Finally, albumin was identified as a mediator in the association between asthma and TB risk. In a core PSM-matched sample, the inverse asthma-TB association remained significant in the final model, whereas the matched-sample albumin-TB and indirect mediation estimates were attenuated.Conclusion Asthma was negatively associated with TB risk, and albumin, among the evaluated oxidative stress-related serum markers, appeared to exert a significant mediating effect on this association. This direction was generally preserved in the matched sensitivity analysis.