Supplementary Table S1.Characteristics of the studies on lung cancer incidence and socioeconomic position
First author (Ref), publication year, country, country‘s income level / Study design / Years of study / Age mean or range / No. of cases / controlstype of controls, matching variables
or
No. of cases / participants, length of follow-up / SEP measure (SEP source):
1) the lowest vs. the highest SEP
2) the middle vs. the highest SEP / RR (95%CI), sex / Controlled variables
Studies adjusted for smoking by matching or statistical adjustment
Hinds MW (13), 1981, US, High-income / CC / 1968-1978 / ≥ 35 / 375 / 2,404 population controls matched by sex and race / Social status (census)
1) Low vs. High
2) Middle vs. High / 0.76 (0.54-1.07) a b F
(all ethnic groups)
0.76 (0.54-1.06) a b F
(all ethnic groups) / Age, smoking
Akiba S (66)c,
1986, Japan, High-income / CC nested in cohort / 1971-1980 / 35-96 / 42 / 108
population controls matched by age, sex, residence, vital status / Occupation (self-reported)
1) Blue collar vs. White collar / 0.90 (0.44-1.85)d F
(non-smokers) / No adjustment
Brownson RC (25), 1987, US, High-income / CC / 1979-1982 / All / 102 / 131 population controls matched by age and sex / Education (self-reported)
1) 0-8 yrs vs. 9-17 yrs
Income (self-reported)
1) < $ 15,000 vs. ≥ $ 15,000 / 1.55 (0.73-3.28) a b M+F
1.18 (1.02-1.39)aM&F / Age, smoking
Age, smoking, residence, work history
Knekt P (79),
1991, Finland, High-income / Cohort / 1966-1984 / 20-75 / 504 / 25,994
18 yrs / Social status(self-reported)
1) Lowest class vs. Highest class
2) Middle class vs. Highest class / 1.60 (0.80-3.20) M
1.60 (0.80-3.10) M / Age, BMI, geographical area, smoking, general health, number of stress symptoms, chest X-ray, chronic cough or use of cough medicine
Hein HO (78),
1992, Denmark, High-income / Cohort / 1970-1988 / 40-59 / 144 / 4,931
18 yrs / Social status (self-reported)
1) Low class (V) vs. High class(I)
2) Middle classes IV/III/II vs. High class (I) / 2.90 (1.50-5.90) M
2.10 (1.38-3.19) b M / Age, smoking
Dosemeci M (12), 1993, Turkey, Middle-income e / CC / 1979-1984 / All / 1,148 / 2,127 hospital controls / Occupation (self-reported)
1) Low group vs. High group
2) Medium group vs. High group / 0.90 (0.70-1.30) M
1.00 (0.70-1.40) M / Age, smoking
Fontham E (74)c, 1994, US, High-income / CC / 1986-1990 / 20-79 / 653 / 1,253
population controls matched by age, race, residence, language, non-smoking status / Income (self-reported)
1) <$8,000 vs. ≥$50,000
2) $8,000-49,999 vs. ≥$50,000 / 1.64 (1.16-2.33)d F
1.12 (0.85-1.47) d F / No adjustment
Xu Z (65),
1996, China, Middle-incomee / CC nested in cohort / 1987-1993 / 30-70 / 610 / 1,100
population controls matched by sex, year of birth / Education (self-reported)
1) No education vs. College
2) Primary/Junior middle/High school vs. College
Income(self-reported)
1) < 15 Yuan/person vs. ≥40 Yuan/person
2) 15 – 39.9 Yuan/person vs. ≥40 Yuan/person / 1.25 (0.72-2.17) aM&F
1.22 (0.90-1.66) a b M&F
0.59 (0.41-0.85) aM&F
0.90 (0.72-1.15) a b M&F / Birth year, smoking, income, fruit and tea consumption, pulmonary diseases, family lung cancer
Birth year, smoking, education, fruit and tea consumption, pulmonary diseases, family lung cancer
Dai X (10)c,
1996, China, Middle-incomee / CC / 1992-1993 / 30-69 / 120 / 120
population controls matched by age, non-smoking status / Income (self-reported)
1)< 50 Yuan/month vs. ≥50 Yuan/month / 3.45 (1.11-11.1) a F / No adjustment
van Loon AJ (63), 1997,
The Netherlands, High-income / Cohort / 1986-1990 / 55-69 / 470 / 1,245
4 yrs / Occupation (self-reported)
1) Blue collar vs. Upper white collar
2) Lower white collar vs. Upper white collar
Education (self-reported)
1) Primary school vs. University
2) Lower vocational/Junior/Senior high school vs. University / 1.05 (0.76-1.47) aM
0.86 (0.52-1.44) aM
1.89 (1.20-2.97) aM
1.92 (1.42-2.60) a bM / Age, smoking, intake of ß carotene, vitamin C, retinol, history of COPD and asthma, exposure to asbestos, paint dust, PAHs and welding fumes
Wunsch-Filho V (16), 1998, Brazil, Middle-incomee / CC / 1990-1991 / 33-90 / 398 / 860
hospital controls matched by age, sex, hospital / Social class(self-reported)
1) Low level 1 vs. High level 4
2) Levels 2/3 vs. High level 4 / 0.59 (0.37-0.95) a b M+F
0.60 (0.39-0.91) a b M+F / Age, smoking
Beeson WL (40)c, 1998, US, High-income / Cohort / 1977-1992 / 27-95 / 36 / 6,338
15 yrs / Education (self-reported)
1) High school or less vs. Some college / 4.33 (2.13-8.80) b d M+F / No adjustment
Droste JH (46),
1999, Belgium, High-income / CC / 1995-1997 / 65 / 478 / 536
hospital controls matched by residence, time of admission / Education (self-reported)
1) Low vs. High
2) Middle vs. High
Social status(self-reported)
1) Low vs. High
2) Middle vs. High / 0.9 (0.5-1.4) M
1.2 (0.8-1.8) M
2.3 (1.5-3.4) M
1.2 (0.8-1.7) M / Age, smoking, marital status, social status
Age, smoking, marital status, education
Nyberg F (72),
2000, Sweden, High-income / CC / 1985-1990 / 40-75 / 1,042 / 2,364 population controls matched by age, year of selection, vital status / Occupation(self-reported)
1) Unskilled blue collar vs. Skilled white collar
2) Skilled blue collar/Unskilled white collar vs. Skilled white collar / 1.35 (1.06-1.72)aM
1.21 (0.97-1.52)a b M / Age, selection year, exposure to traffic related air pollution, radon, occupational exposure to diesel exhaust, other combustion products, asbestos, employment in risk occupation, smoking
Darby S (69)f,
2001, UK, High-income / CC / 1988-1993 / < 75 / 982 / 1,486
population controls matched by age, sex, residence / Occupation(self-reported)
1) Unskilled and partly skilled (V, IV classes) vs. Intermediate and professionals (II and I classes) / 1.52 (1.17-1.98) aM&F / Age, sex, smoking
Mao Y (32),
2001, Canada, High-income / CC / 1994-1997 / ≥ 20 / 3,280 / 5,073
population controls matched by age, sex, province / Education (self-reported)
1) 1-8 yrs vs. ≥ 14 yrs
2) 9-13 yrs vs. ≥ 14 yrs
Occupation (self-reported)
1) Unskilled (V class) vs. Professional (I class)
2) Partly skilled (IV)/ Skilled (IIIN, IIIM)/Intermediate (II) classes vs. Professional (I class)
Income (self-reported)
1) Low income vs.High income
2) Lower middle income/Upper middle vs. High income / 1.67 (1.46-1.91) a b M+F
1.39 (1.18-1.63) a b M+F
1.37 (1.02-1.84)b M+F
1.05 (0.94-1.17) b M+F
1.61 (1.32-1.96) b M+F
1.16 (1.01-1.32) b M+F / Age, province, smoking, exposure to residential or occupational passive smoking, consumption of vegetables and vegetable juices and of meat
Akhmedkhanov A(39), 2002,
US, High-income / CC nested in cohort / 1985-2000 / 31-70 / 81 / 808
hospital controls matched by age, menopausal status at enrolment, date of enrolment, date of response to the 1994-1996 follow-up / Education (self-reported)
1) No college vs. Graduate school
2) College vs.Graduate school / 1.96 (0.97-3.98) aF
1.22 (0.56-2.62)aF / Age, smoking, menopausal status at enrolment, date of enrolment, date of response to the 1994-1996 follow-up
Djousse L (A) (38), The Framingham Study, 2002, US, High-income / Cohort / 1948-1996 / 28-62 / 194 / 4,265
48 yrs / Education (self-reported)
1) Less than high school vs. College and higher
2) High school vs. College and higher / 1.32 (0.88-1.99) d M&F
1.51 (1.04-2.18) d M&F / The risk sets method to control for confounding by age, sex, smoking and year of birth was used in the original study
Djousse L (B) (38), The Framingham Offspring Study, 2002, US, High-income / Cohort / 1971-1996 / All / 75 / 4,898
25 yrs / Education (self-reported)
1) Less than high school vs. College and higher
2) High school vs. College and higher / 8.14 (2.82-23.4) d M&F
2.29 (0.82-6.39) d M&F / The risk sets method to control for confounding by age, sex, smoking and year of birth was used in the original study
Louwman WJ (55)f, 2004,
The Netherlands, High-income / Cohort / 1991-1998 / 15-75 / 125 / 18,973
7 yrs / Education (self-reported)
1) Primary school vs. University / 1.60 (0.80-3.30) M&F / Age, sex, marital status, religion affiliation, degree of urbanisation, smoking, alcohol intake, physical activity
Brennan P (43)cg, 2004, Multicentral: US, Europe, High-income / CC / 1985-1994 (1985-1990 US,
1988-1994 Europe) / All / 1,263 / 2,740
both population and hospital controlsh matched by age, sex, residence, ethnicity, study area / Education (self-reported)
1) Low vs. High
2) Intermediate vs. High / 0.55 (0.45-0.67) d M&F
0.55 (0.46-0.67) d M&F / No adjustment
Kubik A (37),
2004, CzechRepublic, Middle-incomee / CC / 1988-2002 / 25-89 / 419 / 1,593
population controls / Education (self-reported)
1) Elementary school vs. University
2) Secondary school vs. University / 2.30 (1.34-3.94) a b F (smokers and non-smokers)
1.79 (1.10-2.90) a b F (smokers and non-smokers) / Age
Braaten T (42)f,
2005, Norway, High-income / Cohort / 1991-2001 / 30-69 / 150 / 93,638
10 yrs / Education (self-reported)
1) Primary school vs. University / 1.72 (0.75-4.00)aF / Age, smoking, perceived health, total intake of fat
Pukkala E (73)f, 2005,
Finland, High-income / Cohort / 1971-1995 / < 75 / 30,137 / 1,600,000
24 yrs / Occupation (census)
1) Unskilled vs. Higher white collar / 1.67 (1.54-1.82) a M / Age, period and cumulative exposure to crystalline silica dust, cumulative asbestos exposure, smoking
Gorlova O (75)c, 2006, US, High-income / CC / 1995-2003 / 60.2 / 280 / 242
hospital controls matched by age, gender, ethnicity, non-smoking status / Income (self-reported)
1)<$39,999 vs. ≥$75,000
2)$40,000-$74,999 vs. ≥$75,000 / 1.18 (0.76-1.83)d M&F
0.56 (0.38-0.90)d M&F / No adjustment
Ekberg-Aronsson M (26), 2006, Sweden, High-income / Cohort / 1974-2003 / 44 M, 50 F / 550 / 22,387
29 yrs / Occupation (self-reported)
1) Low groups 1 and 2 vs.High groups 3-5 / 1.47 (1.23-1.75) b M+F / Age, marital status
Bardin-Mikolajczak A (24), 2007, Multicentral: Central and Eastern Europe (Romania, Hungary, Poland, Russia, Slovakia, Czech Republic), Middle-incomee / CC / 1998-2001 / 20-79 / 2,632 / 3,784
hospital controls in all countries but Poland, population controls in Polandh matched by sex and age / Education (self-reported data)
1) No formal or some primary education vs.University
2) Primary/some secondary/secondary vs.University / 1.63 (1.24-2.14) a b M+F
1.27 (1.07-1.49)a b M+F / Age, study center, tobacco pack/year
Studies unadjusted for smoking
MacLennan R (15), 1977, Singapore, High-income / CC / 1972-1973 / All / 233 / 300 hospital controls matched by age, sex, dialect / Education (self-reported)
1) No schooling vs. Attended school / 1.13 (0.76-1.69) bdM+F (all races) / No adjustment
Trichopoulos D (62), 1981, Greece, High-income / CC / 1978-1980 / All / 51 / 163 hospital controls matched by date of admission / Education (self-reported)
1) < 6 yrs vs. > 6 yrs / 1.30 (0.68-2.48)d F / No adjustment
GoodmanMT (28), 1988, US, High-income / CC / 1983-1985 / 30-84 / 326 / 865 population controls matched by age, sex / Education(self-reported)
1) < 12 yrs vs. > 12 yrs
2) 12 yrs vs. > 12 yrs
Occupation (self-reported)
1) Blue collar vs. White collar
2) Sales/Service vs. White collar / 1.67 (1.22-2.29) b d M+F
1.43 (1.01-2.03) b d M+F
1.54 (1.10-2.15) b d M+F
1.54 (1.09-2.17) b d M+F / No adjustment
Holst PA (70),
1988,
The Netherlands, High-income / CC / 1985-1987 / <65 / 49 / 98 hospital controls matched by age, sex / Occupation (self-reported)
1) Lower class vs. Higher class / 1.67 (0.76-3.70) dM&F / No adjustment
Xu Z-Y (35),
1989, China, Middle-incomee / CC / 1985-1987 / 30-69 / 1,249 / 1,345 population controls matched by age, sex / Education (self-reported)
1) No formal education vs. University
2) Middle/High school vs. University / 1.73 (1.15-2.61) b d M+F
1.32 (0.91-1.93) b d M+F / No adjustment
Boffetta P (41),
1990, US, High-income / CC / 1977-1987 / All / 2,584 / 5,099 hospital controls matched by age, sex, hospital, year of interview / Education (self-reported)
1) 0-8 yrs vs. 17+ yrs
2) 9-16 yrs vs. 17+ yrs / 2.41 (2.02-2.88) dM
1.53 (1.32-1.76) dM / No adjustment
Katsouyanni K (14), 1991, Greece, High-income / CC / 1987-1989 / >35 / 101 / 89 hospital controls matched by age, date of admission / Education(self-reported)
1) 0 yrs vs. 7+ yrs
2) 1-6 yrs vs. 7+ yrs / 0.56 (0.23-1.36) d F
0.48 (0.25-0.91) d F / No adjustment
Shaw GL (33),
1991, US, High-income / CC / 1976-1980 / 30-79 / 937 / 955 population controls matched by age, sex, ethnicity, vital status / Education (self-reported)
1) ≤ 6 yrs vs. College +
2) 7-15 yrs vs. > College + / 1.15 (0.76-1.74) dM&F
0.93 (0.67-1.28) dM&F / No adjustment
Liu Q (30),
1993, China, Middle-incomee / CC / 1983-1984 / All / 316 / 316 hospital controls matched by age, sex, residence, date of diagnosis or admission / Education (self-reported)
1) < 1 yr vs. ≥ 13 yrs i
2) 1-6/7-12 yrs vs. ≥ 13 yrs i / 1.51 (0.80-2.86) b d M+F
1.22 (0.70-2.11) b d M+F / No adjustment
Ger L-P (48),
1993, Taiwan, High-income / CC / 1990-1991 / All / 131 / 262 population controls matched by age, sex, residence / Education (self-reported)
1) 0 yrs vs. >12 yrs
2) 1-12 yrs vs. >12 yrs / 0.80 (0.41-1.55) dM&F
0.92 (0.53-1.60) dM&F / No adjustment
Suzuki I (61),
1994, Brazil, Middle-incomee / CC / 1991-1992 / 62 / 123 / 123 98 hospital controls matched by age, sex, race / Education (self-reported)
1) None vs. > 4 yrs
2) 1-4 yrs vs. > 4 yrs
Income(self-reported)
1) <min. 1 salary vs.> min. 3 salary
2) 1-3 salary vs.> min. 3 salary / 2.0 (0.88-4.49) dM&F
1.16 (0.63-2.15) dM&F
2.12 (1.09-4.13) fM&F
1.15 (0.65-2.05) fM&F / No adjustment
Faggiano FR (27), 1994, Italy, High-income / CC nested in cohort / 1985-1987 / 20-69 / 1,090 / 4,365 population controls matched by age, sex / Education (census)
1) Primary school vs. University i
2) Middle school vs. University
Occupation (census)
1) Manual workers vs. Managers i
2) Self-employed/Clerks vs. Managers / 1.59 (1.18-2.14) b M+F1.54 (1.19-2.01) b M+F
1.50 (1.16-1.94) b M+F
1.43 (1.16-1.77) b M+F / Age, area of birth, housing tenure
Age, area of birth
Muscat J (58),
1995, US, High-income / CC / 1981-1991 / All / 2,871 / 5,240 hospital controls matched by age / Education (self-reported)
1) < 12 yrsvs.≥ 16 yrs
2)12-15 yrs vs.≥ 16 yrs / 2.09 (1.85-2.37) dM
1.55 (1.41-1.71) dM / No adjustment
Strom SS (60),
1995, US, High-income / CC / NA / 63.8 / 67 / 107 population controls matched by age, sex / Education (self-reported)
1) ≤ 6 yrs vs. ≥13 yrs
2) 7-12 yrs vs. ≥13 yrs / 0.88 (0.32-2.42)dM&F
1.02 (0.37-2.86) dM&F / No adjustment
Knekt P (52),
1996, Finland, High-income / Cohort / 1978-1991 / 30-95 / 70 / 7,018
13 yrs / Education(self-reported)
1) Low level vs. High level
2) Moderate level vs. High level / 4.17 (0.55-31.5) aM
3.54 (2.33-5.39) aM / Age
Parent M-E (76), 1996, Canada, High-income / CC / 1979-1985 / 35-70 / 857 / 533 population controls matched by age / Income(self-reported)
1) ≤$22,000 vs.> $ 28,000
2) $22,001-28,000 vs.> $ 28,000 / 3.89 (2.93-5.18) dM
1.72 (1.30-2.26) dM / No adjustment
Luo R (56),
1996, China, Middle-incomee / CC / 1990-1991 / ≥35 / 102 / 306 population controls matched by age, sex / Education (self-reported)
1) No school vs. Beyond high school
2) Primary/Secondary school vs. > Beyond high school / 0.80 (0.40-1.60) dM&F
0.83 (0.49-1.42) dM&F / No adjustment
Xu X (64),
1996, US, High-income / CC / 1992-1994 / All / 207 / 283 population controls / Education (self-reported)
1) ≤ High school vs. College 3+yrs
2) High school/College 2+yrs vs. College 3+yrs / 2.11 (1.19-3.72) bdM+F
1.13 (0.77-1.66) bdM+F / No adjustment
Pillow PC (77), 1997, US, High-income / CC / NA / 60.9 / 137 / 187 both population and hospital controlsh matched by age, sex, ethnicity / Income(self-reported)
1) <$9,000 vs. ≥$40,000
2) $9,000-39,999 vs. ≥$40,000 / 0.94 (0.40-2.20) dM&F
1.19 (0.54-2.59) dM&F / No adjustment
Armadans-Gil L (67), 1999, Spain, High-income / CC / 1986-1990 / 30-79 / 325 / 325 hospital controls matched by age / Occupation(self-reported)
1) Unskilled (V) vs. Professionals-intermediate (I-II)
2) Partly skilled (IVb)/Manual (IVa)/Non-manual(III) vs. Professionals-intermediate (I-II) / 0.43 (0.16-1.18) d M
0.89 (0.48-1.65) d M / No adjustment
Jahn I (51)g,
1999, Germany, High-income / CC / 1988-1996
(I study 1988-1993, II study 1990-1996) / < 80 / 686 / 712 population controls matched by age, sex, residence / Education(self-reported)
1) < 9 yrs vs. 11-13 yrs
2) 9-10 vs. 11-13 yrs / 2.88 (1.93-4.32) d F
1.53 (0.98-2.40) d F / No adjustment
Marshall B (36), 1999, France, High-income / CC nested in cohort / 1988-1992 / All / 124 / 372 population controls matched by age, time of work / Occupation (self-reported)
1) Production staff vs. Professional
2)Operational/Supervisory staff vs. Professional
Social status (self-reported)
1) Low level vs. High level
2) Medium level vs. High level / 2.51 (1.62-3.89) b M
(all time periods)
1.72 (1.22-2.42) b M
(all time periods)
2.55 (1.59-4.11) b M
(all time periods)
1.85 (1.18-2.91) b M
(all time periods) / No adjustment
Krieger N (29),
1999, US, High-income / Cohort / 1988-1992 / All / 14,601 / 5,379,972
4 yrs / Occupation (census)
1) Working class (poor) vs. Professionals
2) Working class (non-poor) vs. Professionals / 1.52 (1.43-1.61) b M+F (all races)
1.27 (1.24-1.31) b M+F (all races) / Age
Martin J-C (71), 2000, France, High-income / CC nested in cohort / 1978-1989 / 23-60 / 310 / 1,225 population controls matched by age, time of work / Occupation(self-reported)
1) Non-skilled employees vs. Senior executive
2) Skilled/Clerk/Middle vs. Senior executive / 3.08 (1.47-6.47) bM
1.90 (1.20-3.00) bM / No adjustment
Mackillop WJ (31), 2000, US and Canada, High-income / Cohort / 1988-1992 / All / NA / (SEER population and Ontario population)
4 yrs / Income (census)
1) Poorest decile vs. Richest decile / 1.72 (1.67-1.78) M+F / No adjustment
Bruske-Hohlfeld I (45)g, 2000, Germany, High-income / CC / 1988-1996
(I study 1988-1993, II study 1990-1996) / < 80 / 3,541 / 3,498 population controls matched by age, sex, residence / Education (self-reported)
1) < 9 yrs vs.> 12 yrs
2) 9-10/11-12 yrs vs. > 12 yrs / 4.59 (3.13-6.75) d M
3.33 (2.83-3.92) d M / No adjustment
Jackson L (50),
2000, US, High-income / CC / 1993-1996 / 20-74 / 143 / 147 955 population controls matched by age / Education (self-reported)
1) < High schoolvs.High school
2) High schoolvs.High school / 3.33 (1.64-6.76) dM
1.73 (1.04-2.89) dM / No adjustment
Kreienbrock L (53), 2001, Germany, High-income / CC / 1990-1996 / < 75 / 1,449 / 2,297 712 population controls matched by age, sex, region / Education (self-reported)
1) No formal education vs.≥13yrs
2) ≤8/9-10/11-12 yrs vs. ≥ 13 yrs / 4.60 (2.27-9.31)dM&F
3.47 (2.70-4.47) dM&F / No adjustment
Brenner A (44),
2001, China, Middle-incomee / CC / 1994-1998 / 30-75 / 886 / 1,765 population controls matched by age, sex, residence / Education (self-reported)
1)≤ Primary vs. ≥ College
2) Technical vs. ≥ College
Income(self-reported)
1) < 2,000 vs. ≥4,400
2) 2,000-4,399 vs. ≥4,400 / 0.38 (0.20-0.74) dM&F
0.77 (0.40-1.50) dM&F
0.66 (0.53-0.83) dM&F
0.61 (0.51-0.74) dM&F / No adjustment
Moysich K (57), 2002, US, High-income / CC / 1982-1998 / 62.1 / 868 / 935 hospital controls matched by age, sex / Education (self-reported)
1) Up to high schoolvs. College / 2.35 (1.93-2.87) dM&F / No adjustment
StellmanSD (34), 2003, US, High-income / CC / 1984-1998 / All / 3,448 / 8,151
hospital controls matched by age, sex, hospital, year of interview / Education (self-reported)
1) < 12 yrs vs.> 12 yrs
2) 12 yrs vs. > 12 yrs / 1.55 (1.39-1.73) b d M+F
(all races)
1.46 (1.33-1.60) b d M+F (all races) / No adjustment
Fortes C (47),
2003, Italy, High-income / CC / 1993-1996 / 35-90 / 342 / 292 hospital controls matched by age, sex, residence / Education (self-reported)
1) < 8 yrs vs. > 13 yrs
2) 8-13 yrs vs.> 13 yrs / 0.66 (0.25-1.76) aM&F
0.63 (0.26-1.55) aM&F / No adjustment
Richiardi L (59), 2004, Italy, High-income / CC / 1990-1992 / < 75 / 1,171 / 1,553 population controls matched by age, sex / Education (self-reported)
1) < Junior schoolvs. > Junior school
2) Junior school vs. > Junior school / 1.87 (1.48-2.37) bdM+F
1.53 (1.17-2.01) bfM+F / No adjustment
De Stefani E (11), 2005, Uruguay, Middle-incomee / CC / 1994-2000 / 30-89 / 338 / 1,014 hospital controls matched by age, residence, rural/urban status / Education (self-reported)
1) 0-2 yrs vs. 6+ yrs
2) 3-5 yrs vs. 6+ yrs
Income (self-reported)
1) ≤$ 150 vs. $150+ / 1.25 (0.92-1.69) a M
1.01(0.69-1.44) a M
1.11 (0.85-1.45) a M / No adjustment
Hayes JH (49), 2006, US, High-income / Cohort / 1986-1992 / 55-69 / 403 / 27,162
15 yrs / Education (self-reported)
1) <High school graduate vs. Post-high school
2) High school vs. Post-high school / 1.45 (1.11-1.89) aF
1.06 (0.77-1.45) aF / No adjustment
Cassidy A (68), 2006, UK, High-income / CC / 1998-2004 / All / 579 / 1,157 population controls matched by age, sex / Occupation (self-reported)
1)Routine vs. Managerial
2) Lower/Small/Intermediate vs. Managerial / 2.25 (1.68-3.01) dM&F
1.45 (1.05-1.98) dM&F / No adjustment
Krewski D (54) gj, 2005, US, High-income / CC / 1982-1996 / All / 3,662 / 4,966 population controls matched by age, sex, in 3 out of 7 studies – by age, sex, smoking / Education (self-reported)
1) grade level 0-7 vs. level 14+
2) grade level 8-13 vs. level 14+ / 1.46 (1.27-1.68) dM&F
1.53 (1.39-1.69) dM&F / No adjustment
Ref reference,SEP socioeconomic position,RR relative risk,CI confidence interval,CC case-control studies,All all ages,M data on males,F data on females, M+F original data are stratified by sex and then pooled in the analysis to obtain a singlerisk estimate for each SEP from each study,M&F original data are not stratified by sex and presented as a combined risk estimate for males and females,COPD chronic obstructive pulmonary disease,BMI body mass index,PAH polycyclic aromatic hydrocarbons,NA not available
aRR (95% CI) was derived by reversing the original RR if the lowest category of SEP was used as a reference group
b RR (95% CI) was derived by pooling sex- and/or subgroup specific RRs from the studies where separate RRs were provided for different sexes (15, 16, 24-35), races (13, 29, 34), countries (Canada and US) (31), time-periods of working life (beginning of the career, mid-point, time when cancer was diagnosed) (36), smoking statuses (26, 37) or if the middle SEP was presented as several categories
c Studies on non-smokers
d The risk estimates and 95% CIs were recalculated based on raw data presented in the article
e Middle-incomecountry group includes upper middle-income and lower middle-income World Bank groups (17)
f Not enough data to recalculate or reverse original RR (95% CI) for the middle versus the highest SEP
g The original study presents the results of pooled analysis
h Studies by Bardin-Mikolajczak A (24), Brennan P (43) and Pillow PC (77) are not included in the subgroup analysis stratified by type of control since using a combination of population and hospital controls
i For women, in the study by Faggiano FR (27) two educational SEP categories (university degree andhigh school) were originally combined to form the reference group defined as “high school”. In the same study, two occupational SEP categories (managers andclerks) were combined to form the reference group defined as “clerks”. For women, in study by Liu Q (30) the highest educational SEP was defined as “7-12 years of education”
j The study by Krewski D (54), reported combined smoking-adjusted and unadjusted data from 7 case-control studies and was thus only included in the overall analysis and not in the analyses stratified by the adjustment strategy
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