Joint Associations of Multiple Lifestyle Factors With Risk of Active Tuberculosis in the Population: The Singapore Chinese Health Study.

BACKGROUND

Little is known about the joint associations of multiple lifestyle risk factors including smoking, low body mass index, physical inactivity, alcohol consumption, and low diet quality with risk of active tuberculosis.

METHODS

We analyzed data from the Singapore Chinese Health Study, a prospective cohort study of 63 257 Chinese adults aged 45-74 years enrolled between 1993 and 1998. Incident cases of active tuberculosis were identified via linkage with the National TB Registry through 31 December 2016. Cox proportional hazards regression models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) of tuberculosis risk in relation to the combined scores of lifestyle risk factors.

RESULTS

Compared with participants with none of the risk factors, the adjusted HRs (95% CI) of active tuberculosis for participants with 1, 2, 3, 4, and 5 risk factors were 1.24 (1.02-1.51), 1.84 (1.51-2.23), 2.52 (2.03-3.14), 4.07 (3.07-5.41), and 9.04 (5.44-15.02), respectively (Ptrend < .0001). The HR for those with 5 factors was ~1.5 times the product of individual risk estimates from the 5 factors on a multiplicative scale. The stepwise increase in risk of active tuberculosis with increasing number of lifestyle risk factors was significantly stronger in participants with diabetes than their counterparts without diabetes at recruitment (Pinteraction = .01).

CONCLUSIONS

Multiple lifestyle risk factors were associated with risk of active tuberculosis in a synergistic manner. Our findings highlight the importance of public health programs and interventions targeting these factors simultaneously to reduce the tuberculosis burden among the general population.