The association between the diabetes mellitus duration and the risk of pulmonary tuberculosis in the elderly: evidence from a community-based study in China

Background: Diabetes mellitus (DM) is one of the risk factors for pulmonary tuberculosis (TB) development, and the dual burden of these diseases poses a significant public health challenge. However, the impact of DM duration on the risk of pulmonary TB, which is crucial for developing precise intervention strategies, has not been clarified. Methods: We conducted a retrospective study based on an active case-finding project on pulmonary TB in Quzhou City, Zhejiang Province, in 2022, to explore the association between DM duration and the risk of pulmonary TB among elderly individuals aged ≥65 years. We followed participants from the 2022 baseline screening until the date of pulmonary TB diagnosis, death, or 31 December 2024, whichever came first. Results: Among the 212 616 participants with a median age of 72 (interquartile range = 68-76) years, 724 cases with pulmonary TB were reported during the follow-up of 521 173.131 person-years, with an incidence of 138.917/100 000 person-years in 2022-2024. Participants with DM had a significantly higher risk of developing pulmonary TB compared with those without DM (adjusted sub-distribution hazard ratio (aSDHR) = 1.353; 95% confidence interval (CI) = 1.062-1.724). Notably, participants with a DM duration of 2-5 years had a significantly higher risk of pulmonary TB (aSDHR = 2.125; 95% CI = 1.481-3.047), with no other DM duration groups showing significant associations. Conclusions: We found DM to be a risk factor for the development of pulmonary TB, with a particularly pronounced effect in the subgroup with a disease duration of 2-5 years. Further research is needed to verify this association, elucidate its underlying pathophysiological mechanisms, and conduct targeted cost-benefit analyses to provide a basis for public health decision-making.