Nonbiologic risk factors of pulmonary tuberculosis among adults in Henan: a case-control study

OBJECTIVE: To study the nonbiologic risk factors of tuberculosis (TB) among adults. METHODS: 1:2 matched case-control study was conducted. 158 new smear positive pulmonary TB patients with 25 - 60 years of age were notified and registered from three county anti-TB institutions in Henan from October 2002-March 2004, were selected as cases. Two healthy persons were selected to match each case, with the same sex and age group, from the nearest neighbors of the case as controls. Interview was carried out with a uniform designed questionnaire at the residence of the object. Univariate and multivariate condition logistic regression models were used. RESULTS: The results of univariate analysis showed that marital status, education, self-employed occupation, smoking, out-migration for work away from hometown, household annual income level and household property were significantly associated with TB prevalence (P < 0.05); multivariate analysis showed that marital status, self-employed occupation, smoking, household economic condition and out-migration for work, away from home were also associated with TB (P < 0.05), and OR values were 2.826, 2.350, 1.536, 0.707, 2.096, respectively. CONCLUSION: Being single, smoking, self-employed occupation and out-migration for work were nonbiologic risk factors of TB while good household economic condition was a protective factor.