Table 2.
Summary of prevalence estimates for airflow obstruction, restriction, and spirometric SAO in the study population
| BOLD Centre | n | Airflow obstruction n (%) |
Restriction n (%) | Spirometric SAO (FEV3/FVC) n (%) |
Isolated spirometric SAO (FEV3/FVC) n (%) |
Spirometric SAO (FEF25-75) n (%) |
Isolated spirometric SAO (FEF25-75) n (%) |
|---|---|---|---|---|---|---|---|
| Albania (Tirana) | 832 | 82 (10%) | 123 (15%) | 85 (10%) | 22 (3%) | 69 (8%) | 22 (3%) |
| Algeria (Annaba) | 802 | 85 (11%) | 219 (27%) | 75 (9%) | 21 (3%) | 103 (13%) | 54 (7%) |
| Australia (Sydney) | 387 | 58 (15%) | 47 (12%) | 72 (19%) | 25 (7%) | 43 (11%) | 11 (3%) |
| Austria (Salzburg) | 887 | 222 (25%) | 74 (8%) | 271 (31%) | 114 (13%) | 138 (16%) | 25 (3%) |
| Benin (Sémé-Kpodji) | 488 | 55 (11%) | 385 (79%) | 68 (14%) | 36 (7%) | 147 (30%) | 110 (23%) |
| Cameroon (Limbe) | 249 | 14 (6%) | 151 (61%) | 16 (7%) | 7 (3%) | 33 (13%) | 23 (9%) |
| Canada (Vancouver) | 594 | 105 (18%) | 43 (7%) | 135 (23%) | 59 (10%) | 69 (12%) | 17 (3%) |
| China (Guangzhou) | 295 | 33 (11%) | 84 (29%) | 37 (13%) | 17 (6%) | 54 (18%) | 31 (11%) |
| England (London) | 539 | 119 (22%) | 83 (15%) | 163 (30%) | 70 (13%) | 99 (18%) | 31 (6%) |
| Estonia (Tartu) | 545 | 69 (13%) | 45 (8%) | 83 (15%) | 39 (7%) | 29 (5%) | 8 (1%) |
| Germany (Hannover) | 414 | 55 (13%) | 22 (5%) | 53 (13%) | 19 (5%) | 36 (9%) | 10 (2%) |
| Iceland (Reykjavik) | 552 | 116 (21%) | 69 (13%) | 158 (29%) | 63 (12%) | 94 (17%) | 25 (5%) |
| India (Mumbai) | 315 | 26 (8%) | 205 (65%) | 27 (9%) | 9 (3%) | 68 (22%) | 48 (15%) |
| India (Mysore) | 531 | 49 (9%) | 412 (78%) | 55 (10%) | 24 (5%) | 176 (33%) | 140 (26%) |
| India (Pune) | 732 | 65 (9%) | 474 (65%) | 81 (11%) | 36 (5%) | 173 (24%) | 130 (18%) |
| India (Kashmir) | 677 | 144 (21%) | 190 (28%) | 156 (23%) | 45 (7%) | 179 (26%) | 73 (11%) |
| Jamaica | 459 | 45 (10%) | 253 (55%) | 84 (18%) | 48 (10%) | 87 (19%) | 53 (12%) |
| Kyrgyzstan (Chui) | 738 | 141 (19%) | 81 (11%) | 157 (215) | 35 (5%) | 137 (19%) | 25 (3%) |
| Kyrgyzstan (Naryn) | 755 | 84 (11%) | 77 (10%) | 124 (16%) | 58 (8%) | 108 (14%) | 51 (7%) |
| Malawi (Blantyre) | 331 | 33 (10%) | 146 (44%) | 58 (18%) | 31 (10%) | 82 (25%) | 57 (17%) |
| Malawi (Chikwawa) | 366 | 66 (18%) | 135 (37%) | 79 (22%) | 30 (8%) | 108 (30%) | 64 (18%) |
| Malaysia (Penang) | 616 | 25 (4%) | 357 (58%) | 38 (6%) | 21 (3%) | 78 (13%) | 59 (10%) |
| Morocco (Fes) | 429 | 37 (95) | 80 (19%) | 48 (11%) | 15 (3%) | 58 (14%) | 31 (7%) |
| Netherlands (Maastricht) | 538 | 124 (23%) | 51 (9%) | 151 (28%) | 55 (10%) | 95 (18%) | 18 (3%) |
| Nigeria (Ife) | 793 | 98 (12%) | 568 (72%) | 152 (19%) | 76 (10%) | 216 (27%) | 149 (19%) |
| Norway (Bergen) | 447 | 82 (18%) | 39 (9%) | 115 (265) | 60 (14%) | 66 (15%) | 21 (5%) |
| Pakistan (Karachi) | 311 | 38 (12%) | 238 (77%) | 49 (16%) | 23 (7%) | 86 (28%) | 57 (18%) |
| Philippines (Manila) | 651 | 98 (15%) | 404 (62%) | 89 (14%) | 27 (4%) | 154 (24%) | 90 (14%) |
| Philippines (Nampicuan-Talugtug) | 638 | 126 (20%) | 366 (57%) | 127 (20%) | 40 (6%) | 191 (30%) | 112 (18%) |
| Poland (Krakow) | 336 | 64 (19%) | 34 (10%) | 81 (24%) | 33 (10%) | 62 (19%) | 20 (6%) |
| Portugal (Lisbon) | 548 | 57 (10%) | 52 (10%) | 90 (165) | 41 (7%) | 54 (10%) | 16 (3%) |
| Saudi Arabia (Riyadh) | 576 | 31 (5%) | 293 (51%) | 29 (5%) | 7 (1%) | 63 (11%) | 34 (6%) |
| South Africa (Uitsig and Ravensmead) | 505 | 116 (23%) | 232 (46%) | 132 (26%) | 46 (9%) | 159 (31%) | 79 (16%) |
| Sri Lanka (Colombo) | 718 | 77 (11%) | 602 (84%) | 65 (9%) | 12 (25) | 200 (28%) | 146 (20%) |
| Sudan (Gezeira) | 277 | 20 (7%) | 153 (55%) | 30 (11%) | 13 (5%) | 38 (14%) | 21 (8%) |
| Sudan (Khartoum) | 367 | 39 (11%) | 255 (70%) | 56 (15%) | 25 (7%) | 76 (21%) | 50 (14%) |
| Sweden (Uppsala) | 393 | 56 (14%) | 30 (8%) | 56 (14%) | 19 (5%) | 31 (8%) | 11 (3%) |
| Trinidad & Tobago (Port of Spain) | 815 | 59 (7%) | 606 (74%) | 112 (14%) | 72 (9%) | 167 (21%) | 121 (15%) |
| Tunisia (Sousse) | 422 | 29 (7%) | 98 (23%) | 34 (8%) | 16 (4%) | 44 (10%) | 22 (5%) |
| Turkey (Adana) | 414 | 82 (20%) | 56 (14%) | 114 (28%) | 53 (13%) | 89 (22%) | 33 (8%) |
| USA (Lexington) | 312 | 51 (17%) | 72 (23%) | 55 (18%) | 20 (6%) | 69 (22%) | 32 (10%) |
Spirometric SAO: small airways obstruction—Pre-bronchodilator FEF25-75 or FEV3/FVC less than the lower limit of normal (LLN). Isolated spirometric SAO: Pre-bronchodilator FEF25-75 or FEV3/FVC less than the lower limit of normal with FEV1/FVC ≥ LLN. AO: airflow obstruction—pre-bronchodilator FEV1/FVC < LLN. Restriction: Post-bronchodilator FVC < LLN. LLN calculated using spirometry reference equations taken from the NHANES III study population. FVC: Forced vital capacity. FEF25-75: Mean forced expiratory flow rate between 25 and 75% of the FVC. FEV3/FVC: Forced expiratory volume in 3 s as a ratio of the FVC. FEV1/FVC: Forced expiratory volume in 1 s as a ratio of the FVC