Prospective cohort study on tuberculosis incidence and risk factors in the elderly population of eastern China.

ABSTRACT

Background: Tuberculosis continues to be a significant public health concern in China, particularly among the elderly population. This study aimed to assess the risk factors of tuberculosis among elderly individuals in China through a cohort study, focusing on this high-risk population. Methods: The population-based census was strategically designed to cover diverse regions and demographics across the city. The survey captured demographic and lifestyle information, as well as a clinical examination. Participants were prospectively followed up over a specified duration to monitor the incidence of tuberculosis cases. Results: After a follow-up period of more than 7 years, 246 individuals developed tuberculosis, resulting in an incidence rate of 92.21 per 100,000 person-years (95 % CI 81.2-104.3). In multivariate analysis, the following factors were found to have significant associations with active tuberculosis. Increasing age correlated with a higher risk of active tuberculosis (AHR = 1.03 per 1-year increase in age, 95%CI 1.01, 1.04, P < 0.001). Males continued to have a higher risk compared to females (HR = 2.73, 95%CI 2.08, 3.58, P < 0.001). Individuals with a normal Body Mass Index (BMI) faced nearly three times higher risk compared to their obese counterparts (HR = 2.87, 95 % CI 1.51, 5.46, P = 0.001). Conversely, those with an underweight BMI had a ten-fold higher risk compared to the obese group (HR = 9.89, 95 % CI 4.92, 19.85, P < 0.001). Elderly individuals who quit smoking had a 1.35-fold increased risk compared to non-smokers (HR = 1.35, 95%CI 1.12, 1.64, P < 0.001). Conclusions: Tuberculosis incidence among the elderly population in China remained alarmingly high. This finding emphasizes the urgent need for implementing proactive case detection measures specifically tailored to address the specific needs of this vulnerable demographic, particularly in individuals who are male, have a history of former or current smoking, and have a low BMI. Moreover, we must not underestimate the influence of former smoking on tuberculosis risk.