Nonduplicated pooled prevalence estimates for chronic obstructive pulmonary disease by category
| Estimates | Cases | Total population | Prevalence % | Pooled prevalence % | p-value# | |
| Overall | 37 | 111261 | 4123646 | 8.9 (2.1–26.4) | 7.6 (6.0–9.5) | |
| Age | ||||||
| <40 yrs | 9 | 1074 | 25362 | 2.7 (0.8–10.6) | 3.1 (1.8–5.0) | <0.0001 |
| ≥40 yrs | 34 | 4933 | 46095 | 9.7 (1.8–29.7) | 9.9 (8.2–11.8) | |
| 40–64 yrs | 23 | 2793 | 30942 | 7.6 (1.8–28.7) | 8.2 (6.5–10.3) | |
| ≥65 yrs | 11 | 2140 | 15153 | 15.0 (4.8–29.7) | 14.2 (11.0–18.0) | |
| Smoking status | ||||||
| Smoker | 17 | 3133 | 24122 | 15.2 (5.1–39.7) | 15.4 (11.2–20.7) | <0.0001 |
| Ex-smoker | 16 | 1240 | 14521 | 12.7 (2.8–27.7) | 10.7 (8.1–14.0) | |
| Never-smoker | 16 | 1235 | 32542 | 3.9 (0.7–14.6) | 4.3 (3.2–5.7) | |
| Sex | ||||||
| Male | 27 | 16480 | 327293 | 11.0 (2.5–28.0) | 9.8 (8.0–12.1) | 0.0002 |
| Female | 27 | 12024 | 356398 | 5.0 (1.8–25.2) | 5.6 (4.4–7.0) | |
| WHO region | ||||||
| Africa | 0 | 0 | 0 | 0.7768 | ||
| Americas | 3¶ | 2666 | 27599 | 4.5 (3.2–14.0) | 4.6 (2.8–7.6) | |
| Eastern Mediterranean | 0 | 0 | 0 | |||
| Europe | 28 | 104773 | 4015455 | 8.3 (2.1–26.4) | 7.4 (5.9–9.3) | |
| South-East Asia | 2+ | 747 | 6044 | 12.5 (7.1–17.9) | 11.4 (4.4–26.4) | |
| Western Pacific | 4§ | 3075 | 74548 | 10.6 (3.0–18.2) | 9.0 (3.0–24.1) | |
| Study setting | ||||||
| Urban | 12 | 4096 | 44153 | 10.3 (3.6–26.4) | 10.2 (7.4–13.9) | 0.0438 |
| Mixed | 21 | 105571 | 4075965 | 4.9 (2.3–17.8) | 6.1 (4.9–7.7) | |
| Rural | 4 | 437 | 3482 | 8.4 (2.1–18.3) | 8.0 (3.9–15.8) | |
| Study quality | ||||||
| Good | 15 | 23539 | 583658 | 6.8 (3.2–18.3) | 6.8 (5.2–8.9) | 0.6958 |
| Average | 13 | 6434 | 124960 | 7.1 (2.1–14.6) | 6.7 (4.5–9.8) | |
| Poor | 9 | 80131 | 3414982 | 10.5 (2.3–26.4) | 9.9 (4.2–21.6) |
Data are presented as n. Prevalences are presented as median (range) and pooled prevalences as pooled prevalence estimate (95% confidence interval). WHO: World Health Organization. #: heterogeneity between strata calculated using Q statistic (e.g. males versus females); ¶: Canada and USA; +: Thailand and India; §: China, Japan and South Korea. Heterogeneity within each stratum, as calculated by the Q statistic, was significant for all strata with more than one estimate (p<0.0001).