Increasing tuberculosis notification rates among young adults are not associated with migration in Da Nang, Vietnam

Tuberculosis (TB) case notification rates in Vietnam have stabilized since 2000, but in 2007 were increasing among young adults. The emerging HIV epidemic only partly explains this increase. Other factors are probably involved. We aimed to assess whether rural-to-urban migration is such a factor. We conducted a case-control study at district TB units (DTUs) in Da Nang province, Vietnam, recruiting equal numbers (170) of TB patients aged 15-35 years, TB suspects of the same age in whom TB was excluded, and TB patients of 35 years and older. Risk factors for TB were assessed through interviews using pre-structured questionnaires. Among persons seeking care at DTUs, migration was not a significant risk factor for TB. Young male migrants had a lower risk of TB than other young adults (odds ratio (OR) 0.4; 95% confidence interval (95%CI) 0.03-0.64). Instead, TB was associated with male sex and a higher level of education. Compared to older TB patients, younger TB patients were more likely to be female, have a higher education level and a job involving indoor contacts with other people. Migration does not account for the increase in TB case notification rates among young adults in Vietnam. However, migration cannot be excluded as a risk factor for TB in Vietnam, because migrants may not seek diagnosis and treatment for TB at DTUs.