Table 14 Main features of the epidemiological studies of cigarette mentholation and lung cancer
Characteristics | 1. American Health Foundation study | 2. Kaiser Permanente study | 3. Los Angeles County study | 4. Slone Epidemiology Center study |
|---|---|---|---|---|
Source | Kabat and Hebert (1991) [68] | Sidney et al. (1995) [51] | Carpenter et al. (1999) [69] | Brooks et al. (2003) [53] |
Study design | Hospital case-control | Prospective cohort | Population case-control | Hospital case-control |
Location | USA; New York, Chicago, Detroit, Philadelphia | USA; Oakland, California | USA; Los Angeles County, California | USA; New York, Philadelphia, Massachusetts, Maryland |
Timing | 1985-1990 | 1979-1985 followed to 1991 | 1991-1994 | 1981-2000 |
Gender | Both | Both | Both | Both |
Age | Unrestricted | 30 to 89 years at baseline | 40 to 84 years | 40 to 74 years |
Smoking | Current smokers | Current smokers (for 20+ years) | Ever smoked | Ever smoked (for 20+ years) |
Other inclusion criteria | None stated | None stated | Caucasian (non-Hispanic) or African-American people; no previous cancer | Menthol details for 60% of smoking history; no history of cancer |
Cases | 1044 (588M, 456F) | 318 (168M, 150F) | 337 (202M, 135F) | 643 (435M, 208F) |
Cases in mentholated cig smokers | 259 | 93 | 151 | 114 |
Definition of cases | Histologically confirmed, interviewed within 2 months of diagnosis | Incident | Histologically confirmed, interviewed within 7 months of diagnosis | Confirmed by pathology, interviewed within 12 months of diagnosis |
At risk | Not applicable | 5771M, 5990F | Not applicable | Not applicable |
Controls | 1324 (914M, 410F) | Not applicable | 478 (349M, 129F) | 4110 (2123M, 1987F) |
Definition of controls | Diseases unrelated to smoking | Not applicable | Licensed drivers (age < 65) and Medicare beneficiaries (age 65+) | Diseases unrelated to smoking |
Matching of controls | Age, gender, race, hospital, date of interview | Not applicable | Age, gender, race | No matching |
Menthol variable | Time used (< 1, 1-14, 15+ yrs) | Time used (0, 1-9, 10-19, 20+ yrs) | Pack-years menthol (0, 1-15, 16-31, 32+), % menthol (0, 1-19, 20-74, 75-100), cig type (regular only, menthol only, mixed) | Time used (0, 1-15, > 15 years), % years smoked (0, 1-49, 50-100) |
Adjustment for race | Yes | Yes | Yes | Yes |
Adjustment for smoking habits | Cigs/day, inhalation, duration | Cigs/day, duration | Total pack-years, years since quitting | Cigs/day, duration, years since quitting, time used filter cigarettes |
Adjustment for other variables | Age, gender, education, body mass index | Age, gender, education | Age, gendera | Age, gender, year of interview |
Results by histological type | Squamous cell, small cell, large cell, adenocarcinoma | No | No | No |
Study qualityb | 5 | 9 | 7 | 6 |
Characteristics | 5. Second American Health Foundation study | 6. German study | 7. Lung Health study | 8. Houston study |
Source | Stellman et al. (2003) [83] | Jöckel et al. (2004) [84] | Murray et al. (2007) [56] | Etzel et al. (2008) [85] |
Study design | Hospital case-control | Population case-control | Prospective clinical trial | Population case-control |
Location | USA; New York, Chicago, Hines, Detroit, Philadelphia | Germany; location not known | USA and Canada; 10 centres | USA; Houston |
Timing | 1984-1998 | Not known | 1986-1989 followed for 14 years | 1995-2005 |
Gender | Both | Both | Both | Both |
Age | Unrestricted | Unrestricted | 35 to 60 years at baseline | Unrestricted |
Smoking | Current smokers | Ever smokersc | Current smokers | Ever smokers |
Other inclusion criteria | None stated | None stated | Mild or moderate airways obstruction, no defined exclusiond | Black people |
Cases | 1766 (963M, 803F) | 1004 (839M, 165F) | 240M+F | 454M+F |
Cases in mentholated cig smokers | 328 | 50 | About 50 | 198 |
Definition of cases | Histologically confirmed, interviewed within 12 months of diagnosis | Incident | Cause of death | Histologically confirmed, newly diagnosed, untreated, with no prior chemotherapy, radiotherapy or recent blood transfusion |
At risk | Not applicable | Not applicable | 3698M, 2185F | Not applicable |
Controls | 1670 (1098M, 572F) | 1004 (839M, 165F) | Not applicable | 353M+F |
Definition of controls | Diseases unrelated to smoking | Population | Not applicable | Population |
Matching of controls | Age, gender, hospital, year of interview | Age, gender, region | Not applicable | Age, gender, race |
Menthol variable | Preference for menthol | Ever smoked mentholated cigs | Smoked mentholated cigs at baseline | Used mentholated cigarettes |
Adjustment for race | Yes | Subjects White people | Yes | Subjects Black people |
Adjustment for smoking habits | Pack-years | Total amount smoked | Baseline cigs/day | Current/former |
Adjustment for other variables | Age, gender, body mass index, education | Age, gender, region | Age, gender, FEV1, randomization group, education | Age, gendere |
Results by histological type | No | No | No | No |
Study qualityb | 6 | 5 | 8 | 6 |