Background
Methods
Selection of studies
Data entry
Statistical analysis
Software
Results
The studies
Study no. | Referencesb
| Location | Follow-up periodc
| Baseline populationd
| Exclusions |
---|---|---|---|---|---|
General population studies | |||||
1 | Busselton, Australia | 1966-1975 to 1995 | 9,317 men and women ages 18+ attending health surveys | None | |
2 | Beck et al. 1982 [14] | Lebanon, CT, USA | 1972-1978 | 632 white men and women, residents of a rural community ages 25+e
| None |
3 | Boston, MA, USA | 1963-1968 to 1978 | 2,000 male volunteers ages 20-80 (Normative aging study) | Chronic medical conditions | |
4 | Burchfiel et al. 1995 [11] | Hawaii, USA | 1965-1968 to 1975 | 4,451 Japanese-American men ages 45-68 (Honolulu Heart Program) | Unacceptable FEV1 measurements at any time point |
5 | Tucson, AZ USA | 1972-1973 to 1993 | Random sample of 1,705 non-Mexican-American white men and women ages 20+ | Asthmatic, FEV1 < 60% predicted | |
6 | Chambers et al. 1999 [22] | Birmingham, England | 1987-1996 | Inner-city general practice study in 117 men and women ages 45-74 | None |
7 | Western Europe (26 centres), USA (1 centre) | 1991-1993 to 2002 | Random sample of 6,654 men and women ages 20-44 (European Community Respiratory Health Survey) | None | |
8 | Clement and van de Woestijne 1982 [25] | Belgium | 1960-1975 | 2,406 male members of Belgian Air Force ages 20-45 | Less than 3 FEV1 measurements |
9 | Comstock et al. 1970 [26] | USA, four cities | 1962-1963 to 1969 | 527 male telephone workers ages 40-59 | Retired or died by follow-up |
10 | Corbin et al. 1979 [27] | Montreal, QC, Canada | 1971-1976 | 42 men and womenf ages 29-74, smokers attending a smoking cessation clinic, nonsmokers undefined | FEV1/FVC <70% |
11 | Eriksson et al. 1985 [28] | Malmö, Sweden | 1976-1982 | Representative sample of 63 men age 50 | None |
12 | Ferris et al. 1976 [29] | Berlin, NH, USA | 1967-1973 | 1,156 inhabitants of industrial city, mainly ages 25-75g
| None |
13 | London, England | 1961-1969 | 792 men in engineering works and clerical workers ages 30-59 | Asthmatic, malignant disease, heart disease, tuberculosis, 50% of nonsmokers and 20% of smokers without persistent phlegm or chest illness | |
14 | Frew et al. (1992) [32] | Vancouver, BC, Canada | 1981-1983 to 1989 | 733 men ages 15+; grain workers, sawmill workers and office workers | Significant medical disorders or FEV1 < 1.5 L or severe asthma |
15 | Górecka and Czernicka-Cierpisz 1992 [33] | Warsaw, Poland | 1987-1991 | 116 male and female hospital workers ages 19-71h
| No direct contact with patients |
16 | Griffith et al. 2001 [34] | USA, 4 communities | 1989-1993 to 1996 | 5242 men and women ages 65+ (Cardiovascular Health Study of older adults) | Could not give informed consent, terminally ill, institutionalized, unable to walk, likely to move in next 3 years |
17 | Huhti and Ikkala 1980 [35] | Harjavalta, Finland | 1961-1971 | 1,037 men and women in rural population ages 40-64 | Pulmonary tuberculosis, clinically significant respiratory disease (other than asthma or emphysema) |
18 | Humerfelt et al. 1993 [36] | Bergen, Norway | 1965-1970 to 1990 | Random sample of 951 men ages 22-54 | None |
19 | Katoh et al. 2001 [37] | K-town, Japan | 1985-1988 to 2000 | 1,596 men and women ages 39+ | Ever had asthma |
20 | Paris area, France | 1960-1961 to 1972 | 575 working men ages 30-54 | Incorrect spirographs at either survey | |
21 | Krzyzanowski et al. 1986 [41] | Cracow, Poland | 1968-1981 | Random sample of 1,824 male and female residents ages 19-70 | None |
22 | Copenhagen, Denmark | 1976-1978 to 1983 | Random sample of 7,764 men and women ages 20+ from area around hospital (Copenhagen City Heart Study) | Asthmatic, smoked tobacco products other than cigarettes, quit <1 year before end | |
23 | West London, England | 1974-1997 | 227 men ages 20-54 recruited from local employers, supplemented by sample of heavy smokers used in earlier studies | Asthmatic, chest illness, abnormal X-ray | |
24 | Liu and Wang 1999 [48] | Beijing, China | 1987-1997 | 63 men and womenf ages 60+ | Abnormal physical examination, ECG or X-ray; FVC ≤80% of pretest; FEV1 ≤75% of pretest; FEV1/FVC ≤75% |
25 | Olofsson et al. 1986 [49] | Gothenburg, Sweden | 1973-1980 | 460 men born in 1913 (age 60) or in 1923 (age 50) | None |
26 | Omori et al. 2005 [50] | Kumamoto, Japan | 1994-1999 | 1,888 men ages 35-74 attending medical checkup | Asthmatic, other pulmonary disease, X-ray abnormalities, quit smoking before baseline |
27 | Sandvik et al. 1995 [51] | Oslo, Norway | 1972-1975 to 1982 | 1,393 healthy men ages 40-59 working in 5 companies | Heart disease, stroke, cancer, diabetes, hypertension and other miscellaneous diseases |
28 | Sato et al. 1997 [52] | Niita City, Japan | 1983-1986 to 1989 | 429 "healthy" male office workers ages 15-65 | Heart or lung disease |
29 | USA, 6 cities | 1974-1976 to 1988 | Random sample of 8,191 men and women ages 25-74 (Six Cities Study) | None | |
30 | Soejima et al. 2000 [55] | Tokyo, Japan | 1991-1994 to 1999 | 83 men and women ages 35-83 attending Keio University Hospital | Lung cancer, marked lung abnormalities |
31 | Los Angeles, CA, USA | 1973-1978 to 1982 | 2,401 men and women ages 25-64 in 4 areas varying by pollution level | Nonwhites, inconsistent demographics | |
32 | Vlagtwedde and Vlaardingen, Netherlands | 1965-1969 to 1990 | 4,692 men and women ages 15-54 in a rural area and a polluted area | None | |
33 | Villar et al. 1995 [59] | Southampton, England | 1987-1988 to 1992 | 198 men and women ages 65+ randomly selected from 3 general practices | None |
34 | Vollmer et al. 1985 [60] | Portland, OR, USA | 1974-1983 | Random sample of 48 men and women ages 25-54 from Multnomah County | None |
35 | Vollmer et al. 1985 [60] | Portland, OR, USA | 1971-1972 to 1982 | 128 men and women ages 34-83h volunteering for lung function testing | Abnormal FEV1
|
36 | Wilhelmsen et al. 1969 [61] | Gothenburg, Sweden | 1963-1967 | 313 men born in 1913 (age 50) | None |
47 | Kohansal et al. 2009 [62] | Framingham, MA, USA | 1971-1975 to 1977 | 4,391 men and women ages 13-71 (Framingham Offspring Cohort) | None |
Studies of patients with specific diseases | |||||
37 | Annesi et al. 1992 [63] | Paris, France | 1980-1981 to 1986 | 310 male policemen ages 22-55 with some potential risk factors for FEV1 declinei
| None |
38 | Demedts 1988 [64] | Leuven, Belgium | 1975-1985 | 13 male patients ages 41-63 with early emphysemaj
| None |
39 | Grol et al. 1999 [65] | Groningen, Netherlands | 1983-1986 to 1996 | 95 men and women ages 21-33 identified as having allergic asthma when assessed at ages 5-14 | Other specific respiratory diseases, for example, cystic fibrosis or tuberculosis |
40 | Howard 1974 [66] | Sheffield, England | 1966-1972 | 144 men and women ages 42-78h with obstructive airway disease | Ischaemic and rheumatic heart disease, severe physical deformity |
41 | Hughes et al. 1982 [67] | London, England | 1966-1976 to 1979 | 56 men ages 39-71h with emphysema and vascular attenuation or destruction | Other severe lung diseases or abnormalities, thoracic surgery, α1-antitrypsin deficiencyk
|
42 | Postma et al. 1986 [68] | Groningen, Netherlands | 1964-1972 to 1985 | 81 nonallergic men and women ages 30-66h with chronic airflow obstruction and considerable lung function impairmentl
| Other progressive or life-threatening disease, used corticosteroids for >9 months |
Intervention studies | |||||
43 | USA and Canada, 10 centres | 1986-1989 to 2000 | 5,887 men and women ages 35-60 with mild to moderate COPDm who smoked 10+ cigarettes/day within 30 days of screening (Lung Health Study). The subjects were randomly allocated to 3 groups: SIA = special intervention smoking cessation programme plus ipratropium bromide inhaler, SIP = special intervention smoking cessation programme plus placebo inhaler, UC = usual care group | Serious illness, pregnant, used physician-prescribed bronchodilators, β-adrenergic antagonists or systemic glucocorticoids or admitted 25+ drinks/week | |
44 | Soriano et al. 2007 [72] | USA and Europe, 7 trials | Dates not given; 12- to 36-month follow-up period | 1,901 men and women in placebo groups of pooled data from 7 randomized trials of inhaled corticosteroids versus placebo in patients with moderate to severe COPD | Asthmatic, ex-smokers (in one of the 7 trials) |
45 | USA, 22 centres | 1973-1974 to 1982 | 4,926 men ages 35-57 free of heart disease but at high risk based on their blood pressure, serum cholesterol level and cigarette smoking (MRFIT study). The subjects were randomly allocated to 2 groups: SI = special intervention on smoking, diet and antihypertensive medication; UC = usual care | Very high blood pressure or cholesterol, used β-blockers, serious life-threatening disease, believed unable to participate, smoked cigars, cigarettes or pipes, FEV1 measured for <2 years in latter half of follow-up | |
46 | Xie et al. 2001 [75] | China, 3 provinces | 1992-2000 | 869 men and women ages 15+ living in rural areas with chronic respiratory symptomsn and FEV1/FVC ≥ 70%. The areas were randomly allocated to intervention, involving establishment or an organization towards improving medical services, promoting smoking cessation and supplying targeted pharmaceutical treatment, and control. | None |
Characteristic | Level | No. of studies | (%) | Characteristic | Level | No. of studies | (%) |
---|---|---|---|---|---|---|---|
Sex | Both | 28 | (59.6) | Year at enda
| 1960-69 | 3 | (6.4) |
Males only | 19 | (40.4) | 1970-79 | 10 | (21.3) | ||
1980-89 | 15 | (31.9) | |||||
Lowest age | 13-29 | 23 | (48.9) | 1990-99 | 14 | (29.8) | |
30-39 | 10 | (21.3) | 2000+ | 4 | (8.5) | ||
40-49 | 8 | (17.0) | Not knownb
| 1 | (2.1) | ||
50-59 | 3 | (6.4) | |||||
60+ | 3 | (6.4) | Follow-up (yr) | 4-9 | 23 | (48.9) | |
10-14 | 13 | (27.7) | |||||
Highest agec
| < 50 | 3 | (6.4) | 15-19 | 3 | (6.4) | |
50-59 | 12 | (25.5) | 20+ | 7 | (14.9) | ||
60-69 | 8 | (17.0) | Not knownb
| 1 | (2.1) | ||
70+ | 24 | (51.0) | |||||
Study type | Cohort | 43 | (91.5) | ||||
Country | USA | 13 | (27.7) | Intervention | 4 | (8.5) | |
Canada | 2 | (4.3) | |||||
UK | 6 | (12.8) | Population | General | 37 | (78.7) | |
France | 2 | (4.3) | Diseasedd
| 10 | (21.3) | ||
Belgium | 2 | (4.3) | |||||
Netherlands | 3 | (6.4) | Medical exclusions | Some | 25 | (53.2) | |
Sweden | 3 | (6.4) | None | 22 | (46.8) | ||
Norway | 2 | (4.3) | |||||
Denmark | 1 | (2.1) | Subjects (at start) | 13-100 | 9 | (19.1) | |
Finland | 1 | (2.1) | 101-500 | 10 | (21.3) | ||
Poland | 2 | (4.3) | 501-1,000 | 7 | (14.9) | ||
Japan | 4 | (8.5) | 1,001-5,000 | 15 | (31.9) | ||
China | 2 | (4.3) | > 5,000 | 6 | (12.8) | ||
Australia | 1 | (2.1) | |||||
Multicountry | 3 | (6.4) | Betas adjusted | None | 29 | (61.7) | |
Some | 18 | (38.3) | |||||
Year at start | 1960-69 | 16 | (34.0) | ||||
1970-79 | 15 | (31.9) | |||||
1980-89 | 11 | (23.4) | |||||
1990-99 | 4 | (8.5) | |||||
Not knownb
| 1 | (2.1) |
Estimates of FEV1decline by smoking habit ("betas")
Selection of betas for the main analyses comparing the four smoking groups
Stratifying variables | Follow-up (yr) | No. of adjusted | Beta (SE)d
| |||||||
---|---|---|---|---|---|---|---|---|---|---|
Study no. | Reference | Sex | Age rangea
| Otherb
| variablesc
| Nevere smokers | Ex-smokersf
| Quittersg
| Continuing smokersh
| |
1 | Bartholomew and Knuiman [12] | M | 19-44 | - | 6 | 2 | 36.8 (6.2) | 14.0 (11.2) | 54.7 (7.1) | |
M | 45+ | - | 6 | 2 | 45.8 (6.4) | 51.2 (7.9) | 60.5 (6.5) | |||
F | 19-44 | - | 6 | 2 | 24.3 (6.6) | -15.3 (11.3) | 13.7 (10.8) | |||
F | 45+ | - | 6 | 2 | 30.7 (4.7) | 35.2 (7.4) | 46.5 (10.3) | |||
2 | Beck et al. [14] | M | 25-34 | - | 6 | 0 | -20.7 (9.5) | 0.8 (12.1) | -3.0 (9.8) | |
M | 35-44 | - | 6 | 0 | 2.5 (15.0) | -14.3 (8.8) | 19.5 (9.1) | |||
M | 45+ | - | 6 | 0 | 20.0 (4.9) | 31.0 (3.4) | 25.5 (5.3) | |||
F | 25-34 | - | 6 | 0 | -8.5 (6.9) | -32.5 (11.5) | 15.2 (8.3) | |||
F | 35-44 | - | 6 | 0 | 18.8 (7.5) | 13.5 (12.0) | 20.8 (8.6) | |||
F | 45+ | - | 6 | 0 | 10.3 (2.9) | 10.7 (5.0) | 32.0 (5.8) | |||
3 | Bossé et al. [16] | M | 20-34 | - | 5 | 1 | 23.0 (9.0) | 24.0 (11.0) | 57.0 (8.0) | |
M | 35-42 | - | 5 | 1 | 47.0 (7.0) | 61.0 (12.0) | 76.0 (6.0) | |||
M | 43-80 | - | 5 | 1 | 82.0 (7.0) | 73.0 (9.0) | 101.0 (7.0) | |||
4 | Burchfiel et al. [11] | M | 45-49 | - | 6 | 1 | 19.5 (2.9) | 19.8 (3.1) | 21.2 (4.9) | 31.3 (2.4) |
M | 50-59 | - | 6 | 1 | 21.6 (1.8) | 21.5 (2.0) | 28.3 (3.3) | 32.4 (1.8) | ||
M | 60-68 | - | 6 | 1 | 25.0 (3.2) | 26.0 (3.4) | 35.1 (6.1) | 40.1 (3.5) | ||
5 | Camilli et al. [21] | M | 20-34 | - | 9.4 | 0 | 1.0 (6.1) | -9.0 (15.2) | -22.0 (12.4) | 6.0 (7.2) |
M | 35-49 | - | 9.4 | 0 | 9.0 (8.3) | 1.0 (9.8) | 12.0 (13.5) | 18.0 (7.6) | ||
M | 50-69 | - | 9.4 | 0 | 19.0 (7.1) | 24.0 (5.4) | 34.0 (10.0) | 40.0 (5.8) | ||
M | 70+ | - | 9.4 | 0 | 25.0 (3.8) | 26.0 (3.2) | 37.0 (7.7) | 26.0 (7.7) | ||
F | 20-34 | - | 9.4 | 0 | -5.0 (5.5) | -18.0 (13.2) | -27.0 (14.1) | -4.0 (8.0) | ||
F | 35-49 | - | 9.4 | 0 | 6.0 (6.5) | 4.0 (9.1) | 7.0 (17.4) | 12.0 (7.4) | ||
F | 50-69 | - | 9.4 | 0 | 13.0 (3.9) | 15.0 (5.8) | 17.0 (9.1) | 21.0 (5.0) | ||
F | 70+ | - | 9.4 | 0 | 21.0 (2.1) | 20.0 (4.6) | 25.0 (7.7) | 26.0 (6.1) | ||
6 | Chambers et al. [22] | M+F | 45-74 | - | 9 | 0 | 43.5 (4.4) | 47.3 (6.4) | 41.1 (19.3) | 52.0 (4.4) |
7 | Chinn et al. [23] | M | 20-44 | - | 8 | 0 | 32.0 (1.1) | 31.0 (1.6) | 31.0 (2.1) | 35.0 (1.4) |
F | 20-44 | - | 8 | 0 | 24.0 (0.7) | 27.0 (1.2) | 22.0 (1.8) | 27.0 (1.1) | ||
9 | Comstock et al. [26] | M | 40-59 | - | 5.25 | 0 | 32.4 (7.1) | 78.1 (3.1) | ||
10 | Corbin et al. [27] | M+F | 29-74i
| - | 4j
| 0 | -8.6 (15.0) | 35.0 (16.3) | 20.0 (11.4) | |
12 | Ferris et al. [29] | M | 25-74 | - | 6 | 2 | -10.0 (4.9) | -6.7 (4.5) | ||
F | 25-74 | - | 6 | 2 | -8.3 (2.6) | 0.0 (7.2) | ||||
13 | Fletcher et al. [6] | M | 30-59 | F1 | 8 | 4 | 36.0 (9.0) | 34.0 (6.0) | 37.0 (11.0) | 60.5 (2.2) |
M | 30-59 | F2 | 8 | 4 | 45.0 (6.0) | 36.0 (5.0) | 47.0 (11.0) | 47.6 (2.3) | ||
M | 30-59 | F3 | 8 | 4 | 33.0 (3.0) | 26.0 (4.0) | 26.0 (14.0) | 40.4 (2.2) | ||
17 | Huhti et al. [76] | M | 40-64 | - | 10 | 0 | 33.0 (3.4) | 45.0 (3.1) | 44.0 (4.0) | 51.0 (2.4) |
F | 40-64 | - | 10 | 0 | 27.0 (1.0) | 27.0 (4.7) | 39.0 (6.9) | 35.0 (3.5) | ||
18 | Humerfelt et al. [36] | M | 22-54 | - | 23 | 0 | 46.6 (1.4) | 47.0 (1.3) | 51.5 (1.1) | |
19 | Katoh et al. [37] | M | 39+ | - | 12 | 0 | 30.0 (1.9) | 31.7 (1.8) | 37.9 (2.1) | 39.2 (1.5) |
F | 39+ | - | 12 | 0 | 20.8 (0.5) | 21.7 (2.5) | 16.7 (5.2) | 30.8 (4.2) | ||
20 | M | 30-54 | - | 12 | 2k
| 40.8 (4.8) | 49.4 (4.1) | 46.1 (1.6) | ||
21 | Krzyzanowski et al. [41] | M | 19-70 | - | 13 | 2 | 47.3 (4.1) | 50.4 (5.3) | 66.5 (4.4) | 59.7 (2.6) |
F | 19-70 | - | 13 | 2 | 38.3 (1.9) | 30.1 (9.6) | 37.3 (6.9) | 42.0 (3.6) | ||
22 | Lange et al. [42] | M | 20-54 | - | 5 | 0 | 21.0 (7.0) | 27.0 (7.0) | ||
M | 55+ | - | 5 | 0 | 34.0 (9.0) | 36.0 (5.0) | ||||
F | 20-54 | - | 5 | 0 | 13.0 (3.0) | 18.0 (5.0) | ||||
F | 55+ | - | 5 | 0 | 32.0 (3.0) | 32.0 (4.0) | ||||
23 | Watson et al. [47] | M | 20-54 | - | 22 | 0 | 34.2 (2.2) | 33.1 (2.8) | 38.8 (3.3) | 51.0 (4.0) |
25 | Olofsson et al. [49] | M | 50 | - | 7 | 0 | 54.3 (8.5) | |||
M | 60 | - | 7 | 0 | 57.1 (6.3) | |||||
26 | Omori et al. [50] | M | 35-44 | - | 5 | 0 | 32.8 (8.3) | 38.8 (6.1) | 33.7 (4.0) | |
M | 45-54 | - | 5 | 0 | 31.9 (2.9) | 35.3 (2.7) | 44.5 (2.1) | |||
M | 55-64 | - | 5 | 0 | 31.3 (2.9) | 35.4 (2.7) | 38.9 (2.7) | |||
M | 65-74 | - | 5 | 0 | 33.9 (3.1) | 30.4 (4.2) | 43.1 (4.5) | |||
27 | Sandvik et al. [51] | M | 40-49 | - | 7l
| 0 | 10.3 (6.4) | 31.7 (4.3) | ||
M | 50-59 | - | 7l
| 0 | 27.4 (4.8) | 45.4 (4.8) | ||||
28 | Sato et al. [52] | M | 15-65m
| - | 3 | 0 | 2.0 (12.4) | 18.0 (16.9) | 36.0 (7.9) | |
29 | Xu et al. [54] | M | 25-34 | - | 6 | 1 | 15.2 | 6.4 | -6.2 | 34.2 |
M | 35-44 | - | 6 | 1 | 24.9 | 23.9 | 47.4 | 34.5 | ||
M | 45-54 | - | 6 | 1 | 41.9 | 39.4 | 32.2 | 63.8 | ||
M | 55-64 | - | 6 | 1 | 45.9 | 43.2 | 66.7 | 60.4 | ||
M | 65-78 | - | 6 | 1 | 55.6 | 52.3 | 60.2 | 63.3 | ||
M | 25-74 | - | 6 | 2 | 37.8 (2.0) | 34.3 (1.8) | 41.2 (5.0) | 52.9 (2.0) | ||
F | 25-34 | - | 6 | 1 | 13.8 | 13.9 | -7.4 | 22.2 | ||
F | 35-44 | - | 6 | 1 | 25.0 | 29.8 | 6.2 | 34.9 | ||
F | 45-54 | - | 6 | 1 | 30.4 | 26.0 | 31.7 | 40.1 | ||
F | 55-64 | - | 6 | 1 | 34.1 | 40.6 | 38.9 | 48.3 | ||
F | 65-78 | - | 6 | 1 | 39.2 | 34.9 | 70.1 | 38.2 | ||
F | 25-74 | - | 6 | 2 | 29.0 (0.9) | 29.6 (1.6) | 28.7 (4.3) | 38.0 (1.2) | ||
30 | Soejima et al. [55] | M+F | 35-83n
| - | 5 | 0 | 20.0 (1.7) | 30.0 (8.7) | 60.0 (3.4) | |
31 | Tashkin et al. [56] | M | 25-64 | - | 5 | 3 | 56.0 (2.6) | 52.0 (3.0) | 62.0 (5.1) | 70.0 (3.1) |
F | 25-64 | - | 5 | 3 | 42.0 (1.9) | 38.0 (2.8) | 38.0 (6.6) | 54.0 (4.0) | ||
32 | Xu et al. [4] | M | 25-54 | - | 24 | 0 | 6.1 (7.2) | |||
F | 25-54 | - | 24 | 0 | 2.7 (6.1) | |||||
Rijcken et al. [5] | M | 25-54 | H0 | 24 | 1 | 30.8 (9.8) | 28.5 (5.0) | 37.1 (4.5) | ||
F | 25-54 | H0 | 24 | 1 | 24.9 (3.9) | 24.7 (7.2) | 27.3 (5.1) | |||
M | 25-54 | H1 | 24 | 1 | 41.2 (17.0) | 33.0 (8.0) | 40.3 (6.5) | |||
F | 25-54 | H1 | 24 | 1 | 25.3 (6.0) | 30.6 (9.6) | 33.1 (6.4) | |||
34 | Vollmer et al. [60] | M+F | 25-54 | B1 | 9 | 0 | 38.0 (52.1) | 89.0 (19.7) | 67.0 (26.1) | |
M+F | 25-54 | B0 | 9 | 0 | 43.0 (30.1) | 43.0 (11.4) | 45.0 (15.0) | |||
35 | Vollmer et al. [60] | M+F | 34-83 | B1 | 11 | 0 | 49.0 (18.5) | 70.0 (17.3) | 70.0 (11.9) | |
M+F | 34-83 | B0 | 11 | 0 | 37.0 (10.7) | 56.0 (10.0) | 60.0 (6.9) | |||
36 | Wilhelmsen et al. [61] | M | 50 | - | 4 | 0 | 40.0 (16.8) | 73.2 (7.1) | ||
37 | Annesi et al. [63] | M | 22-55 | I1 | 5 | 0 | 31.7 (5.9) | 51.7 (5.8) | ||
M | 22-55 | I2 | 5 | 0 | 59.7 (9.8) | 32.7 (8.8) | ||||
38 | Demedts [64] | M | 41-63o
| - | 10 | 0 | 72.5 (37.5) | 88.8 (21.4) | 98.4 (10.8) | |
39 | Grol et al. [65] | M+F | 21-33 | - | 11 | 0 | 19.7 (8.0) | -26.4 (23.6) | 23.4 (11.5) | |
41 | Hughes et al. [67] | M | 44-69 | - | 8 | 0 | 16.4 (8.8) | |||
42 | Postma et al. [68] | M+F | 30-66 | - | 11 | 0 | 49.0 (7.0) | 85.0 (5.1) | ||
43 | Kanner et al. [70]p
| M+F | 35-60 | D1 | 5 | 0 | 13.1 (1.8) | 55.9 (1.0) | ||
M+F | 35-60 | D2 | 5 | 0 | 27.6 (5.7) | 58.5 (3.0) | ||||
M+F | 35-60 | D3 | 5 | 0 | 24.0 (7.8) | 63.4 (3.0) | ||||
M+F | 35-60 | D4 | 5 | 0 | 20.3 (8.7) | 66.4 (3.7) | ||||
M+F | 35-60 | D5 | 5 | 0 | 12.0 (11.9) | 69.4 (4.7) | ||||
44 | Soriano et al. [72]q
| M | 40+ | - | 1.5 | 1 | 16.0 (2.7) | 21.3 (2.0) | ||
F | 40+ | - | 1.5 | 1 | 11.3 (4.3) | 16.7 (2.0) | ||||
45 | Townsend [73]p
| M | 35-57 | - | 7 | 0 | 39.5 | 40.0 | 40.0 (4.7) | 62.3 (2.8) |
46 | Xie et al. [75]p
| M+F | 15+ | - | 8 | 5 | 39.5 (3.3) | 37.3 (2.2) | ||
47 | Kohansal et al. [62] | M | 13-71 | - | 23 | 0 | 19.6 (1.3) | 38.2 (2.2) | ||
F | 13-71 | - | 23 | 0 | 17.6 (1.9) | 23.9 (1.6) |
Comparison of betas in the four smoking groups
Never smokersb
(95% CI) | Ex-smokersc
(95% CI) | Quittersd
(95% CI) | Continuing smokerse
(95% CI) | ||
---|---|---|---|---|---|
Unweighted analysisf
| |||||
Number of betas | 80 | 66 | 64 | 85 | |
Unadjusted | Mean | 27.9 (23.5-32.4) | 24.1 (19.2-29.1) | 33.4 (28.4-38.4) | 42.8 (38.5-47.2) |
Diff 1 | -14.9*** | -18.7*** | -9.4** | Base | |
Diff 2 | Base | -3.8NS
| +5.5NS
| +14.9*** | |
Adjusted for age and sex | Mean | 28.8 (25.0-32.7) | 24.6(20.3-28.8) | 33.0 (28.7-37.3) | 41.9 (38.2-45.6) |
Diff 1 | -13.1*** | -17.4*** | -8.9** | Base | |
Diff 2 | Base | -4.3NS
| +4.2NS
| +13.1*** | |
Adjusted for blockg
| |||||
(fixed-effects model) | Mean | 28.7 (26.4-30.9) | 27.0 (24.5-29.5) | 30.4 (27.9-33.0) | 42.1 (40.0-44.3) |
Diff 1 | -13.5*** | -15.2*** | -11.7*** | Base | |
Diff 2 | Base | -1.7NS
| +1.7NS
| +13.5*** | |
(random-effects model) | Mean | 28.6 (24.4-32.9) | 26.6 (22.2-31.0) | 30.6 (26.2-35.1) | 42.2 (38.0-46.4) |
Diff 1 | -13.6*** | -15.6*** | -11.6*** | Base | |
Diff 2 | Base | -2.1NS
| +2.0NS
| +13.6*** | |
Weighted analysish
| |||||
Number of betas | 71 | 57 | 56 | 77 | |
Unadjusted | Mean | 26.1 (23.9-28.3) | 29.3 (25.6-32.9) | 38.3 (33.5-43.2) | 41.8 (39.1-44.6) |
Diff 1 | -15.7*** | -12.6*** | -3.5NS
| Base | |
Diff 2 | Base | +3.1NS
| +12.2*** | +15.7*** | |
Adjusted for age and sex | Mean | 28.9 (27.0-30.9) | 27.9 (24.8-30.9) | 34.2 (30.1-38.4) | 39.5 (37.2-41.9) |
Diff 1 | -10.6*** | -11.6*** | -5.3* | Base | |
Diff 2 | Base | -1.1NS
| +5.3* | +10.6*** | |
Adjusted for blockg
| |||||
(fixed-effects model) | Mean | 29.2 (28.1-30.4) | 27.6 (25.9-29.4) | 31.6 (29.1-34.1) | 40.1 (38.6-41.5) |
Diff 1 | -10.8*** | -12.4*** | -8.5*** | Base | |
Diff 2 | Base | -1.6NS
| +2.4NS
| +10.8*** | |
(random-effects model) | Mean | 29.6 (25.6-33.5) | 28.0 (23.9-32.1) | 32.2 (27.8-36.7) | 40.8 (36.9-44.8) |
Diff 1 | -11.3*** | -12.8*** | -8.6*** | Base | |
Diff 2 | Base | -1.5NS
| +2.7NS
| +11.3*** |
Heterogeneity of betas
Relationship of beta to age, sex and study characteristics
Unweighted analysis | Inverse variance-weighted analysis | ||||||
---|---|---|---|---|---|---|---|
Factor | Level | Number of betas | Beta (95% CI) |
Pvaluea
| Number of betas | Beta (95% CI) |
Pvaluea
|
Sexb
| Males | 168 | 35.8 (33.1-38.4) | Base | 150 | 34.6 (32.7-36.5) | Base |
Females | 88 | 23.9 (20.2-27.7) | --- | 72 | 28.3 (26.3-30.3) | --- | |
Both | 39 | 38.2 (32.5-43.9) | NS | 39 | 40.7 (36.2-45.3) | + | |
Agec
| < 40 | 47 | 13.2 (8.2-18.3) | Base | 39 | 28.7 (25.8-31.5) | Base |
40-49 | 78 | 33.9 (30.0-37.8) | +++ | 68 | 42.8 (39.6-46.1) | +++ | |
50-69 | 123 | 37.8 (34.7-41.0) | +++ | 115 | 32.1 (30.1-34.1) | NS | |
70+ | 47 | 35.8 (30.7-40.9) | +++ | 39 | 27.9 (25.2-30.6) | NS | |
Length of follow-up period | Per year | 295 | -0.16 (-0.57 to 0.25) | NS | 261 | -0.03 (-0.27 to 0.21) | NS |
Continent | North America | 148 | 30.3 (27.5-33.1) | Base | 114 | 29.0 (26.1-32.0) | Base |
Europe | 85 | 36.7 (32.9-40.5) | ++ | 85 | 34.8 (31.5-38.1) | ++ | |
Asia | 28 | 26.3 (19.7-32.8) | NS | 28 | 31.6 (28.2-35.1) | NS | |
Australasia | 12 | 41.9 (31.6-52.1) | + | 12 | 42.1 (27.5-56.7) | NS | |
Multicountry | 22 | 34.9 (27.2-42.7) | NS | 22 | 34.3 (30.0-38.6) | NS | |
Final follow-up year | < 1980 | 78 | 27.0 (23.3-30.6) | Base | 78 | 25.7 (22.8-28.6) | Base |
1980-1989 | 98 | 42.3 (39.1-45.4) | +++ | 64 | 37.9 (34.8-41.1) | +++ | |
1990-1999 | 91 | 26.0 (22.7-29.3) | NS | 91 | 27.6 (25.0-30.3) | NS | |
2000+ | 28 | 35.6 (29.3-42.0) | + | 28 | 35.8 (33.1-38.4) | +++ | |
Publication year | < 1980 | 26 | 27.1 (20.1-34.1) | Base | 26 | 26.3 (20.5-32.0) | Base |
1980-1989 | 129 | 33.2 (30.2-36.3) | NS | 129 | 35.0 (32.1-37.9) | ++ | |
1990-1999 | 99 | 34.2 (30.7-37.6) | NS | 65 | 35.1 (32.5-37.8) | ++ | |
2000+ | 41 | 30.0 (24.4-35.5) | NS | 41 | 30.2 (27.9-32.4) | NS | |
Population type | General | 266 | 32.5 (30.4-34.6) | Base | 232 | 32.7 (31.4-34.1) | Base |
Diseased | 29 | 32.9 (25.8-40.1) | NS | 29 | 28.3 (22.3-34.4) | NS | |
Study type | Prospective | 275 | 32.9 (30.8-35.0) | Base | 243 | 32.7 (31.4-34.1) | Base |
intervention | 20 | 27.6 (19.2-36.0) | NS | 18 | 28.4 (22.6-34.3) | NS |
Differences in betas between continuing smokers and those who gave up smoking
Variation by age, sex and study characteristics in differences in beta between continuing smokers and those who gave up smoking
Relationship of beta to amount smoked in continuing smokers
Stratifying variables | ||||||
---|---|---|---|---|---|---|
Study no. | Reference | Sex | Age | Otherb
| Amount smoked (cigarettes/day)c
| Beta (SE) |
4 | Burchfiel et al. [11] | M | 45-68 | - | 1-19, 20-29, 30-39, 40+ | 29.8 (3.5), 32.4 (2.0), 35.5 (2.8), 34.3 (2.7) |
12 | Ferris et al. [29] | M | 25-74 | - | 1-24, 25+ | 0.0 (5.7), 6.7 (5.8) |
F | 25-74 | - | 1-24, 25+ | 1.7 (4.4), 1.7 (8.3) | ||
13 | Fletcher et al. [6] | M | 30-59 | F1 | 1-5, 6-15, 16-25, 26+ | 45.0 (5.0), 55.0 (4.0), 74.0 (5.0), 63.0 (6.0) |
M | 30-59 | F2 | 1-5, 6-15, 16-25, 26+ | 37.0 (6.0), 49.0 (4.0), 51.0 (4.0), 45.0 (10.0) | ||
M | 30-59 | F3 | 1-5, 6-15, 16-25, 26+ | 39.0 (4.0), 39.0 (4.0), 38.0 (5.0), 52.0 (11.0) | ||
22 | Lange et al. [42] | M | 20-54 | - | 1-14, 15+ | 22.0 (6.0), 42.0 (5.0) |
M | 55+ | - | 1-14, 15+ | 52.0 (3.0), 56.0 (6.0) | ||
F | 20-54 | - | 1-14, 15+ | 17.0 (4.0), 30.0 (4.0) | ||
F | 55+ | 1-14, 15+ | 39.0 (3.0), 48.0 (5.0) | |||
29 | Xu et al. [54] | M | 25-34 | - | 1-14, 15-24, 25+ | 36.5, 20.6, 41.7 |
M | 35-44 | - | 1-14, 15-24, 25+ | 30.4, 40.3, 39.0 | ||
M | 45-54 | - | 1-14, 15-24, 25+ | 55.0, 57.4, 68.8 | ||
M | 55-64 | - | 1-14, 15-24, 25+ | 49.0, 53.8, 68.5 | ||
M | 65-78 | - | 1-14, 15-24, 25+ | 66.8, 54.1, 73.4 | ||
M | 25-74 | - | 1-14, 15-24, 25+ | 37.4 (6.0), 47.2 (3.6), 59.9 (3.5) | ||
F | 25-34 | - | 1-14, 15-24, 25+ | 16.5, 21.9, 28.0 | ||
F | 35-44 | - | 1-14, 15-24, 25+ | 28.9, 35.8, 36.9 | ||
F | 45-54 | - | 1-14, 15-24, 25+ | 32.5, 45.7, 37.8 | ||
F | 55-64 | - | 1-14, 15-24, 25+ | 42.7, 52.0, 50.4 | ||
F | 65-78 | - | 1-14, 15-24, 25+ | 29.4, 47.9, 37.4 | ||
F | 25-74 | - | 1-14, 15-24, 25+ | 31.2 (2.4), 42.0 (1.8), 38.9 (2.5) | ||
31 | Tashkin et al. [57] | M | 25-59 | - | 1-20, 21+ | 77.8 (6.2), 81.8 (5.0) |
F | 25-59 | - | 1-20, 21+ | 52.3 (3.3), 61.7 (3.7) | ||
32 | Xu et al. [4] | M | 25-54 | - | 1-14, 15-24, 25+ | 18.8 (5.3), 26.3 (4.2), 33.2 (4.9) |
F | 25-54 | - | 1-14, 15-24, 25+ | 15.0 (4.0), 20.4 (5.1), 30.1 (7.6) |
Relationship of some other factors to beta and differences in betas between smoking groups
Trend (SE)b
| |||||||||
---|---|---|---|---|---|---|---|---|---|
Factor | Levels | Study no. | Ref. | Sex | Age range at baseline | Continuing smokers | Quitters | Ex-smokers | |
Baseline FEV1 (cL/m3) | 65+, 55-64, 1-54 | 13 | Fletcher et al. [6] | Male | 30-59 | Mean | 10.0 (1.5)*** | 4.0 (8.8) | 4.8 (3.5) |
Diffc
| Base | 6.2 (8.9) | 5.1 (3.8) | ||||||
Baseline FEV1 (mL) | High, middle, low | 4 | Burchfiel et al. [11] | Male | 45-68 | Mean | -24.8 (1.6)*** | -16.1 (5.3)** | |
Diff | Base | -8.8 (5.6) | |||||||
Baseline FEV1 (mL/m3) | 500+, 1-499 | 45 | Townsend [73] | Male | 35-57 | Mean | 28.1 (8.6)** | 21.2 (15.6) | |
Diff | Base | 6.9 (17.8) | |||||||
Baseline FEV1/FVC (%) | 80+, 70-79, 1-69 | 5 | Burrows et al. [10] | Male | 20-70 | Mean | 27.9 (4.2)*** | -3.4 (5.5) | |
Diff | Base | 31.3 (6.9)*** | |||||||
Obstruction at baseline | None, mild | 13 | Fletcher and Peto [31] | Male | 30-59 | Mean | 24.8 (16.4) | 7.0 (9.4) | |
Diff | Base | 17.8 (18.9) | |||||||
Obstruction at baseline | None, mild | 13 | Fletcher et al. [6] | Male | 30-59 | Mean | 22.1 (11.4) | 4.0 (8.5) | |
Diff | Base | 18.1 (14.3) | |||||||
Doctor visits for LRId
| 0-0.24, 0.25-0.49, 0.50-0.99, 1.00-1.49, 1.50+ | 43 | Kanner et al. [70] | Male | 35-60 | Mean | 3.5 (0.8)*** | 2.9 (1.9) | |
Diff | Base | 0.7 (2.0) | |||||||
Respiratory symptoms at baseline | No, Yes | 29 | Sherman et al. [53] | Male | 25-74 | Mean | 4.6 (4.0) | 4.3 (3.1) | |
Diff | Base | 0.3 (5.1) | |||||||
Respiratory symptoms at baseline | No, Yes | 29 | Sherman et al. [53] | Female | 25-74 | Mean | 1.9 (2.4) | -5.9 (5.0) | |
Diff | Base | 7.8 (5.5) | |||||||
Bronchodilator responsiveness | No, Yes | 34 | Vollmer et al. [60] | Both | 25-54 | Mean | 22.0 (30.1) | 46.0 (22.7) | |
Diff | Base | -24.0 (37.7) | |||||||
Bronchodilator responsiveness | No, Yes | 35 | Vollmer et al. [60] | Both | 25-54 | Mean | 10.0 (13.7) | 14.0 (20.0) | |
Diff | Base | -4.0 (24.2) | |||||||
Histamine responsiveness | No, Yes | 32 | Rijcken et al. [5] | Male | 25-54 | Mean | 3.2 (7.9) | 4.5 (9.4) | |
Diff | Base | -1.3 (12.3) | |||||||
Histamine responsiveness | No, Yes | 32 | Rijcken et al. [5] | Female | 25-54 | Mean | 5.8 (8.2) | 5.9 (12.0) | |
Diff | Base | -0.1 (14.5) | |||||||
Occupational exposure | None, low, high | 7 | Sunyer et al. [24] | Male | 20-44 | Mean | 0.8 | -1.1 | |
Diff | Base | 1.8 | |||||||
Occupational exposure | None, low, high | 7 | Sunyer et al. [24] | Female | 20-44 | Mean | 1.2 | 6.2 | |
Diff | Base | -5.0 | |||||||
Exposure to gas and fumes | None, low, high | 7 | Sunyer et al. [24] | Male | 20-44 | Mean | 1.5 | -2.9 | |
Diff | Base | 4.4 | |||||||
Exposure to gas and fumes | None, low, high | 7 | Sunyer et al. [24] | Females | 20-44 | Mean | -3.2 | 5.6 | |
Diff | Base | -8.9 | |||||||
Biological dust exposure | None, low, high | 7 | Sunyer et al. [24] | Males | 20-44 | Mean | 0.2 | 2.5 | |
Diff | Base | -2.3 | |||||||
Biological dust exposure | None, low, high | 7 | Sunyer et al. [24] | Females | 20-44 | Mean | 6.8 | 5.6 | |
Diff | Base | 1.2 | |||||||
Mineral dust exposure | None, low, high | 7 | Sunyer et al. [24] | Males | 20-44 | Mean | 0.0 | 2.3 | |
Diff | Base | -2.3 | |||||||
Mineral dust exposure | None, low, high | 7 | Sunyer et al. [24] | Females | 20-44 | Mean | 2.0 | 6.5 | |
Diff | Base | -4.5 |