The 13th World Conference on Tobacco OR Health

Objective:

To review the evidence linking smoking and tuberculosis in Hong Kong and other parts of China

Methods:

To examine published studies and discuss their significance against the background prevalence of both conditions

Results:

Despite successful implementation of DOTS, the annual tuberculosis notification rate is around 90/100,000 in Hong Kong, while the prevalence of pulmonary tuberculosis was 367/100000 in a survey undertaken in 2000 in Mainland China.

Smoking has previously been found to be an important risk factor of TB in both cross-sectional and mortality studies in different parts of China. More aggressive pulmonary involvement, with more cough, dyspnoea, upper zone involvement, cavity, miliary lung involvement and positive sputum culture, has also been found among ever-smoking TB patients in comparison with never-smokers.

In a prospective community cohort of 42,655 elderly subjects in Hong Kong, the annual TB notification rates were 735, 427, and 174 per 100,000 among current smokers, ex-smokers and never-smokers respectively. A statistically significant dose-response relationship was also observed among current smokers. The excess risk applied to pulmonary but not extrapulmonary TB. Smoking cessation almost halved the risk. The trend persisted after control of relevant background characteristics. Smoking accounted for 32.8%, 8.6% and 18.7% of the TB risk among males, females and the whole cohort respectively. About 45% of the gender difference was attributable to smoking.

The interaction between smoking and the rapidly aging population in a high-burden country poses a serious threat. Measures on tobacco control should therefore be considered alongside DOTS in the fight against TB.