Table 1.

Association between different patterns of sun exposure and total body nevus number, number of large normal nevi, and presence of atypical nevi adjusted for case-control status

Sun exposuren (%)Total body nevus number*No. of large neviPresence of atypical nevi
Controls median (Q1, Q3)Cases median (Q1, Q3)β (95% CI)PtrendRate ratio (95% CI)PtrendRisk ratio (95% CI)PtrendPtrend§
Sunburn under age 20 y
    No902 (68)15 (7, 29)42 (21, 76)
    Yes423 (32)18 (10, 37)42 (22, 98)0.03 (−0.08 to 0.15)0.551.09 (0.90-1.32)0.371.12 (0.92-1.38)0.250.20
Sunburn at/over age 20 y
    No802 (61)14 (6, 29)42 (21, 83)
    Yes504 (39)19 (10, 36)43 (20, 89)0.10 (−0.01 to 0.21)0.061.18 (0.98-1.41)0.081.07 (0.87-1.30)0.540.86
Average weekday exposure at cooler months (h/d)
    ≤0.9463 (34)15 (7, 32)42 (23, 79)
    0.9-1.5463 (34)17 (8, 29)43 (20, 85)0.01 (−0.12 to 0.13)1.09 (0.88, 1.34)0.83 (0.65, 1.04)
    >1.5440 (32)15 (6, 29)42 (22, 89)0.01 (−0.12 to 0.13)0.911.15 (0.92-1.43)0.220.96 (0.76-1.20)0.680.84
Average weekday exposure at warmer months (h/d)
    ≤1.4489 (36)15 (8, 28)42 (23, 84)
    1.4-2.1415 (30)17 (7, 32)42 (21, 81)0.03 (−0.10 to 0.15)0.97 (0.78-1.21)0.78 (0.61-0.99)
    >2.1466 (34)15 (6, 29)43 (20, 89)−0.01 (−0.13 to 0.11)0.871.21 (0.98-1.49)0.070.86 (0.69-1.07)0.160.23
Average weekend exposure at cooler months (h/d)
    ≤2.5498 (36)14 (7, 30)44 (23, 78)
    2.5-3.5466 (34)17 (8, 34)41 (20, 85)0.04 (−0.08 to 0.16)1.18 (0.96-1.45)0.90 (0.71-1.12)
    >3.5416 (30)15 (6, 28)44 (20, 94)−0.03 (−0.15 to 0.10)0.711.01 (0.81-1.26)0.840.94 (0.75-1.19)0.580.82
Average weekend exposure at warmer months (h/d)
    ≤4.0538 (39)14 (7, 27)42 (21, 78)
    4.0-5.0424 (31)15 (6, 31)46 (23, 94)0.03 (−0.09 to 0.15)1.07 (0.87-1.32)1.15 (0.92-1.45)
    >5.0417 (30)18 (7, 36)41 (19, 87)−0.04 (−0.17 to 0.08)0.520.98 (0.80-1.22)0.941.15 (0.91-1.45)0.210.10
Average daily exposure (h/d)
    ≤1.9492 (36)15 (7, 29)44 (24, 80)
    1.9-2.5419 (31)17 (8, 34)40 (21, 88)−0.01 (−0.13 to 0.12)0.94 (0.76-1.17)0.91 (0.72-1.15)
    >2.5443 (33)15 (6, 29)43 (20, 89)−0.06 (−0.18 to 0.07)0.381.16 (0.94-1.43)0.180.91 (0.72-1.14)0.390.68
Average holiday exposure (h/y)
    ≤46.5493 (36)14 (5, 27)33 (19, 59)
    46.5-71.5411 (30)15 (7, 31)48 (25, 93)0.23 (0.10-0.35)1.29 (1.03-1.60)1.45 (1.14-1.84)
    >71.5467 (34)17 (10, 34)51 (23, 97)0.29 (0.17-0.41)<0.00011.38 (1.12-1.71)0.0021.24 (0.97-1.58)0.080.38
Average holiday exposure (10 am-2 pm; h/y)
    ≤23.3502 (37)14 (5, 26)34 (19, 63)
    23.3-38.0435 (32)15 (7, 31)50 (26, 96)0.28 (0.16-0.40)1.15 (0.93-1.43)1.15 (0.91-1.45)
    >38.0429 (31)17 (10, 36)46 (21, 93)0.28 (0.16-0.40)<0.00011.33 (1.07-1.64)0.0091.08 (0.85, 1.37)0.480.85
Average holiday exposure below 45°N (h/y)
    ≤6.5456 (33)11 (4, 23)30 (14, 61)
    6.5-26.7446 (33)15 (8, 34)42 (23, 87)0.19 (0.07-0.32)1.03 (0.83-1.28)1.58 (1.21-2.04)
    >26.7469 (34)20 (10, 36)56 (27, 101)0.31 (0.19-0.43)<0.00011.06 (0.85-1.31)0.611.57 (1.21-2.02)0.00060.01
Average holiday exposure below 45°N (10 am-2 pm; h/y)
    ≤3.3471 (35)12 (4, 23)32 (17, 61)
    3.3-13.0434 (32)15 (8, 32)43 (23, 94)0.20 (0.07-0.32)1.03 (0.83-1.28)1.58 (1.22-2.03)
    >13.0461 (34)20 (10, 35)52 (26, 96)0.26 (0.13-0.38)<0.00010.98 (0.79-1.22)0.881.51 (1.17-1.94)0.0010.02
  • *Median total body nevus number (first quartile, third quartile) for controls and cases are presented separately but subsequent analyses are for the total sample adjusted for case-control status. Age-sex–corrected log-transformed body nevus number was used to test for association, and the linear regression coefficient (β) and its 95% CIs are presented.

  • Analyses were carried out using Negative Binomial regression models, and rate ratios are presented.

  • Modified Poisson regression models with robust error variance were used to analyze presence of atypical nevi and risk ratios are presented.

  • §Log-transformed body nevus number was further adjusted for in the trend test.