Patterns of tuberculosis risk over time among recent immigrants to Ontario, Canada

Int J Tuberc Lung Dis. 2005 Jun;9(6):667-72.


Setting: Canada receives more than 200000 immigrants annually. Immigrants account for 92% of tuberculosis (TB) cases in Toronto, Ontario. Epidemiological profiling of recent immigrants is needed to provide more effective TB programs.

Design: A population-based, retrospective cohort study of recent immigrants to Ontario, 1990-1997. We generated adjusted rates, risk ratios (RRs), hazard rates since arrival, and a complementary log-log model to describe TB risk, compare the survival distributions between different sexes, age groups and world regions of birth, and determine predictors of disease.

Results: TB in recent immigrants was 23 times (95%CI 20.9-25.5) higher than in Canadian-born, non-aboriginal people. Those aged 16-30 and >65 years experienced the highest rates. Sub-Saharan Africa had the highest rates for both sexes (RR 95.5, 95%CI 84.3-108.2), followed by India and Asia. Hazard rates decreased after arrival, but remained elevated. The highest risk was associated with arrival in 1990 and living in Canada <1 year.

Conclusion: Risk for TB varied by region of birth, age at landing and time since arrival. Sex was not significant. Persons from sub-Saharan Africa and age >65 years were the highest risk groups. Risk decreased significantly in the first 1-2 years after arrival, after which it plateaued.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Age Distribution
  • Aged
  • Child
  • Child, Preschool
  • Cohort Studies
  • Emigration and Immigration*
  • Female
  • Humans
  • Incidence
  • Infant
  • Infant, Newborn
  • Male
  • Middle Aged
  • Ontario / epidemiology
  • Retrospective Studies
  • Risk Factors
  • Sex Distribution
  • Tuberculosis / epidemiology*
  • Tuberculosis / prevention & control*