Dietary Cholesterol Increases the Risk whereas PUFAs Reduce the Risk of Active Tuberculosis in Singapore Chinese

Background: Experimental studies suggest that cholesterol enhances the intracellular survival of Mycobacterium tuberculosis, whereas marine omega-3 (n-3) and omega-6 (n-6) fatty acids (FAs) may modulate responses to M. tuberculosis in macrophage and animal models. However, there are no epidemiologic data from prospective studies of the relation between dietary cholesterol and FAs and the risk of developing active tuberculosis. Objective: We aimed to investigate the relation between dietary intake of cholesterol and FAs and the risk of active tuberculosis in a prospective cohort in Singapore. Methods: We analyzed data from the Singapore Chinese Health Study, a cohort of 63,257 Chinese men and women aged 45-74 y recruited between 1993 and 1998. Dietary intake of cholesterol and FAs was determined with the use of a validated food-frequency questionnaire. Incident cases of active tuberculosis were identified via linkage with the nationwide tuberculosis registry. Analysis was performed with the use of Cox proportional hazards models. Results: As of 31 December 2013, 1136 incident cases of active tuberculosis were identified. Dietary cholesterol was positively associated with an increased risk of active tuberculosis in a dose-dependent manner. Compared with the lowest intake quartile, the HR was 1.22 (95% CI: 1.00, 1.47) for the highest quartile (P-trend = 0.04). Conversely, dietary marine n-3 and n-6 FAs were associated with a reduced risk of active tuberculosis in a dose-dependent manner. Compared with the lowest quartile, the HR for the highest intake quartile was 0.77 (95% Cl: 0.62, 0.95) for marine n-3 FAs (P-trend = 0.01) and 0.82 (95% CI: 0.68, 0.98) for n-6 FAs (P-trend = 0.03). There was no association with saturated, monounsaturated, or plant-based n-3 FA intake. Conclusion: Dietary intake of cholesterol may increase the risk of active tuberculosis, whereas marine n-3 and n-6 FAs may reduce the risk of active tuberculosis in the Chinese population.