Table 1.
Characteristics of study subjects.
| Cases | Controls | |||
|---|---|---|---|---|
| Characteristic | n | (%) | n | (%) |
| 51 | (100) | 51 | (100) | |
| Sex | ||||
| Male | 23 | (44.1) | 23 | (44.1) |
| Female | 28 | (54.9) | 28 | (54.9) |
| Age | ||||
| 25–49 y | 17 | (33.3) | 16 | (31.4) |
| 50–79 y | 34 | (66.7) | 35 | (68.6) |
| Educational attainment level | ||||
| Elementary school or less | 18 | (35.3) | 17 | (33.3) |
| Middle school | 8 | (15.7) | 8 | (15.7) |
| High school | 17 | (33.3) | 17 | (33.3) |
| College or more | 8 | (15.7) | 9 | (17.7) |
| Phototype | ||||
| I | 3 | (5.9) | 1 | (2.0) |
| II | 25 | (49.0) | 16 | (31.4) |
| III | 21 | (41.2) | 29 | (56.8) |
| IV | 0 | (0.0) | 5 | (9.8) |
| Missing | 2 | (3.9) | 0 | (0) |
| Sun exposure (days per year) | ||||
| 0 | 6 | (11.8) | 3 | (5.9) |
| <15 | 23 | (45.1) | 10 | (19.6) |
| 15–30 | 16 | (31.4) | 27 | (52.9) |
| >30 | 5 | (9.7) | 11 | (21.6) |
| Missing | 1 | (2) | 0 | (0) |
| Life-time history of sunburns | ||||
| 0 | 21 | (41.2) | 33 | (64.7) |
| 1 | 24 | (47.1) | 14 | (27.5) |
| 2 | 2 | (3.9) | 2 | (3.9) |
| >2 | 2 | (3.9) | 2 | (3.9) |
| Missing | 2 | (3.9) | 0 | (0) |