Prevalence of tuberculous infection and incidence of tuberculosis; a re-assessment of the Styblo rule
F van Leth, MJ van der Werf, MW Borgdorff
Volume 86, Number 1, January 2008, 20-26
Table 2. Number of tuberculous infections and smear-positive TB cases per 100 000 population, by country and yeara
| Country | Yeara | Infections | Smear-positive TB | Infection-to-disease ratio | 95% CI of ratio |
|---|---|---|---|---|---|
| Republic of Korea |
1975 | 1780 | 480 | 3.7 | 2.9–4.5 |
| 1980 | 1240 | 310 | 4.0 | 2.7–5.3 | |
| 1985 | 1120 | 240 | 4.7 | 3.5–5.9 | |
| 1990 | 60 | 144 | 3.2 | 1.6–4.8 | |
| China |
1979 | 640 | 187 | 3.4 | Not doneb |
| 1985 | 590 | 156 | 3.8 | Not doneb | |
| China |
1990 | 638 | 134 | 4.8 | Not doneb |
| 1996 | 700 | 121 | 5.8 | Not doneb | |
| Philippines |
1982 | 2480 | 950 | 2.6 | Not doneb |
| 1994 | 2300 | 525 | 4.4 | 3.9–4.9 |
CI, confidence interval; TB, tuberculosis; TST, tuberculin skin test.a The year for the number of infections is derived from the midpoint between the birth of the cohort and the year of the actual tuberculin survey.b Not done due to missing information of denominator in TST survey.