Description of study population (subpopulations of the original study with individually assigned NO2 measures) of all five cohorts as used at each assessment
| Asthma-E3N | ECRHS | NSHD | SALIA | SAPALDIA | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Study Co-variables | Assessment 2011 N=4070 | Assessment 1998–2002 N=5053 | Assessment 1999 N=2322 | Assessment 2008 N=2024 | Assessment 1985–1994 N=4360 | Assessment 2006–2010 N=2019 | Assessment 1991 N=3766 | Assessment 2002 N=2113 | ||||||||
| N/Mean | % /SD | N/Mean | % /SD | N/Mean | % /SD | N/Mean | % /SD | N/Mean | % /SD | N/Mean | % /SD | N/Mean | % /SD | N/Mean | % /SD | |
| Female | 4070 | 100% | 2712 | 53.7% | 1216 | 52.4% | 1075 | 53.1% | 4360 | 100% | 2019 | 100% | 1949 | 51.8% | 1126 | 53.3% |
| Age, years | 70.0 | 6.4 | 42.9 | 7.1 | 53.5 | 0.2 | 61.9 | 0.6 | 54.5 | 0.6 | 71.5 | 3.4 | 41.3 | 11.8 | 53.1 | 11.5 |
| Body mass index (BMI), kg/m2 | 24.0 | 4.5 | 25.7 | 4.6 | 27.4 | 4.7 | 27.9 | 4.9 | 27.6 | 4.7 | 26.9 | 4.3 | 23.7 | 3.9 | 25.5 | 4.3 |
| Smoking pack years* | 3.5 | 10.2 | 12.2 | 18.2 | 10.3 | 13.6 | 10.7 | 15.2 | 4.1 | 10.3 | 4.3 | 11.9 | 11.8 | 19.0 | 13.8 | 22.4 |
| Never-smoker | 2770 | 68.0% | 2086 | 41.3% | 708 | 30.5% | 644 | 31.8% | 3230 | 74.1% | 1607 | 79.6% | 1571 | 41.7% | 853 | 40.4% |
| Ex-smoker | 1041 | 25.6% | 1364 | 27.0% | 1133 | 48.8% | 1141 | 56.4% | 378 | 8.7% | 304 | 15.1% | 809 | 21.5% | 678 | 32.1% |
| Current smoker | 259 | 6.4% | 1603 | 31.7% | 481 | 20.7% | 239 | 11.8% | 752 | 17.2% | 108 | 5.3% | 1386 | 36.8% | 582 | 27.5% |
| Low education | 107 | 2.6% | 1471 | 29.1% | 965 | 41.6% | 798 | 39.4% | 1260 | 28.9% | 438 | 21.7% | 574 | 15.2% | 137 | 6.5% |
| Medium education | 246 | 6.1% | 1732 | 34.3% | 1105 | 47.6% | 994 | 49.1% | 2100 | 48.2% | 986 | 48.8% | 2410 | 64.0% | 1352 | 64.0% |
| High education | 3717 | 91.3% | 1850 | 36.6% | 252 | 10.9% | 232 | 11.5% | 1000 | 22.9% | 595 | 29.5% | 782 | 20.8% | 624 | 29.5% |
| ETS exposures | 168 | 5.1% | 506 | 10.0% | 523 | 25.0% | 452 | 24.6% | 2205 | 50.9% | 976 | 49.2% | 518 | 13.8% | 146 | 6.9% |
| VGDF exposures | 879 | 23.2% | 2146 | 44.4% | 721 | 35.1% | 632 | 34.8% | 428 | 9.8% | 184 | 9.1% | 1060 | 28.2% | 581 | 27.5% |
| Asthmatics† | 967 | 26.6% | 782 | 15.5% | 221 | 10.0% | 192 | 9.8% | 102 | 2.4% | 121 | 6.4% | 296 | 7.9% | 181 | 8.6% |
| COPD Gold stage 1 plus‡ | n/a | n/a | 305 | 7.2% | 110 | 6.6% | 92 | 8.2% | 289 | 12.5% | 102 | 15.4% | 395 | 11.4% | 399 | 20.6% |
Table shows the N (and % of N) for categorical variables and mean (SD) for continuous variables.
*Calculations based on ex-smokers and current smokers.
†Asthmatics cases were defined as those who answered ‘yes’ to ever-asthma questions in the questionnaires of all cohorts.
‡Stages of COPD were classified according to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) definitions and NHANES III (Third National Health and Nutrition Examination Survey) reference equations. There were no lung function test conducted in Asthma-E3N cohort hence results were n/a (not applicable). Only pre-bronchodilator spirometric measurements were available for all cohorts.
ECRHS, European Community Respiratory Health Survey; ETS, Environmental Tobacco Smoke at home and/or at work; NSHD, National Survey of Health and Development; SALIA, Study on the influence of Air pollution on Lung function, Inflammation and Aging; SAPALDIA, Swiss cohort study on Air Pollution And Lung and heart Diseases in Adults; VGDF, occupational vapour/gases/dust/fumes exposure (any of).