Table 1: Characteristics of study subjects.

CasesControls
Characteristic (%) (%)
51(100)51(100)

Sex
 Male23(44.1)23(44.1)
 Female28(54.9)28(54.9)
Age
 25–49 y17(33.3)16(31.4)
 50–79 y34(66.7)35(68.6)
Educational attainment level
 Elementary school or less18(35.3)17(33.3)
 Middle school8(15.7)8(15.7)
 High school17(33.3)17(33.3)
 College or more8(15.7)9(17.7)
Phototype
 I3(5.9)1(2.0)
 II25(49.0)16(31.4)
 III21(41.2)29(56.8)
 IV0(0.0)5(9.8)
 Missing2(3.9)0(0)
Sun exposure (days per year)
 06(11.8)3(5.9)
1523(45.1)10(19.6)
 15–3016(31.4)27(52.9)
305(9.7)11(21.6)
 Missing1(2)0(0)
Life-time history of sunburns
 021(41.2)33(64.7)
 124(47.1)14(27.5)
 22(3.9)2(3.9)
22(3.9)2(3.9)
 Missing2(3.9)0(0)