Table 3.

The association between indoor tanning history with melanoma risk (Skin Health Study)

Indoor tanningCasesControlsAge- and gender-adjusted OR (95% CI)Multivariate adjusted OR* (95% CI)
n (%)n (%)
Never used433 (37.1)538 (48.9)1.001.00
Ever used734 (62.9)563 (51.1)1.81 (1.51-2.21)1.74 (1.42-2.14)
Frequency of use (h)
    1-9322 (27.6)289 (26.2)1.58 (1.28-1.96)1.46 (1.15-1.85)
    10-1974 (6.3)66 (6.0)1.62 (1.12-2.34)1.81 (1.21-2.70)
    20-49129 (11.1)90 (8.2)2.10 (1.53-2.88)2.18 (1.54-3.08)
    50+200 (17.1)95 (8.6)3.27 (2.42-4.41)3.18 (2.28-4.43)
    P trend<0.0001<0.0001
Frequency of use, sessions
    ≤10149 (12.8)141 (12.8)1.47 (1.12-1.93)1.34 (1.00-1.81)
    11-24130 (11.1)100 (9.1)1.84 (1.36-2.48)1.80 (1.30-2.49)
    25-100173 (14.8)147 (13.4)1.71 (1.30-2.23)1.68 (1.25-2.26)
    >100275 (23.6)154 (14.0)2.71 (2.08-3.51)2.72 (2.04-3.63)
    P trend0.00050.0002
Age at initiation (y)
    <18209 (17.9)161 (14.6)2.18 (1.62-2.94)1.85 (1.33-2.57)
    18-24175 (15.0)125 (11.4)2.14 (1.60-2.85)1.91 (1.39-2.62)
    25-34150 (12.9)143 (13.0)1.43 (1.09-1,87)1.46 (1.09-1.97)
    35+199 (17.1)134 (12.1)1.79 (1.38-2.33)1.83 (1.37-2.43)
    P trend0.370.68
Duration of use (y)
    1123 (10.5)110 (10.0)1.52 (1.13-2.03)1.47 (1.06-2.02)
    2-5236 (20.2)194 (17.6)1.74 (1.36-2.21)1.64 (1.26-2.15)
    6-9124 (10.6)95 (8.6)1.93 (1.41-2.64)1.85 (1.31-2.61)
    10+245 (21.0)146 (13.3)2.47 (1.90-3.21)2.45 (1.83-3.28)
    P trend0.00360.006
Burns from indoor tanning
    No476 (40.8)410 (37.2)1.60 (1.32-1.95)1.59 (1.28-1.97)
    Yes258 (22.1)153 (13.9)2.60 (2.00-3.39)2.28 (1.71-3.04)
Number of times burned, indoor tanning
    162 (5.3)37 (3.4)2.46 (1.59-3.82)2.40 (1.49-3.87)
    253 (4.5)41 (3.7)1.99 (1.28-3.10)1.83 (1.13-2.99)
    3-570 (6.0)46 (4.2)2.42 (1.60-3.66)2.05 (1.31-3.20)
    >572 (6.2)29 (2.6)4.04 (2.52-6.49)3.12 (1.86-5.23)
    P trend0.00010.01
Burns from sun after indoor tanning
    No536 (45.9)435 (39.5)1.71 (1.41-2.08)1.67 (1.35-2.07)
    Yes195 (16.7)127 (11.5)2.19 (1.67-2.88)2.00 (1.48-2.70)
  • *Adjusted for age, gender, eye color, natural hair color, skin color, freckles, moles, income, education, family history of melanoma, routine sun exposure, outdoor activity sun exposure, outdoor job exposure, mean sunscreen use, and number of lifetime painful sunburns; an additional 16 cases and 12 controls were excluded because the number of missing values was too small to be included as its own category.

  • *Adjusted for age, gender, eye color, natural hair color, skin color, freckles, moles, income, education, family history of melanoma, routine sun exposure, outdoor activity sun exposure, outdoor job exposure, mean sunscreen use, and number of lifetime painful sunburns; an additional 16 cases and 12 controls were excluded because the number of missing values was too small to be included as its own category.