Characteristic | Level | N (%) | Characteristic | Level | N (%) |
---|---|---|---|---|---|
Study design | Â | Â | Cases in mentholated cigarette smokers | Â | Â |
 | Prospective cohort | 2 (25.0) |  | 50-124 | 4 (50.0) |
 | Hospital case-control | 3 (37.5) |  | 125+ | 4 (50.0) |
 | Population case-control | 3 (37.5) |  |  |  |
 |  |  | Controls matched on age and gender |  |  |
Country | Â | Â | Â | Yes | 5 (62.5) |
 | USA | 7 (87.5) |  | No | 1 (12.5) |
 | Germany | 1 (12.5) |  | Prospective | 2 (25.0) |
First year of study | Â | Â | Menthol dose-response studied | Â | Â |
 | 1979 to 1985 | 3 (37.5) |  | Yes | 4 (50.0) |
 | 1986 to 1995 | 4 (50.0) |  | No | 4 (50.0) |
 | Not known | 1 (12.5) |  |  |  |
 |  |  | Race accounted for |  |  |
Year of publication | Â | Â | Â | Yes | 8 (100.0) |
 | 1991 to 2000 | 3 (37.5) |  |  |  |
 | 2001 to 2008 | 5 (62.5) | Smoking adjusted for |  |  |
 |  |  |  | Yes | 8 (100.0) |
Genders studied | Â | Â | Â | Â | Â |
 | Both | 8 (100.0) |  |  |  |
 |  |  | Age adjusted for | Yes | 8 (100.0) |
Smoking groups used in analysis | Â | Â | Â | Â | Â |
 | Current | 4 (50.0) | Results by histological type | Yes | 1 (12.5) |
 | Ever | 4 (50.0) |  | No | 7 (87.5) |
Cases studied | Â | Â | Â | Â | Â |
 | 200-499 | 4 (50.0) | NOS study quality score | 7 to 9 | 3 (37.5) |
 | 500-999 | 1 (12.5) |  | 5 to 6 | 5 (62.5) |
 | 1000+ | 3 (37.5) |  |  |  |