Fig. 1

Age-standardized prevalence ratio of latent tuberculosis infection within age strata and visa type. A < 40 years old; B ≥ 40 years old; C Korean diaspora; D other visa type. The box shows the age-standardized prevalence ratio, and the vertical lines represent the 95% confidence intervals. Variables: country of origin (high TB burden and low-intermediate TB burden), visa type (Korean diaspora and others), duration of stay (< 1 year, 1–4 years, and ≥ 5 years), and age (< 40 and ≥ 40 years). TB = tuberculosis; LTBI = latent tuberculosis infection