Skip to main content
. 2008 Nov 10;169(1):41–53. doi: 10.1093/aje/kwn289

Table 3.

Univariate Analyses of Back Freckling, Sun-Exposure Variables, and Log Total Nevus Count, Adjusted for the Linear and Quadratic Effect of Sun Sensitivity Index, in a Study of Nevi in Children, Framingham, Massachusetts, 2004

Variable and Response Category Sample Size Rate Ratio 95% CI P value
On a typical day during the week this past summer between 10 AM and 4 PM, how many hours did you spend at the beach or pool?
    <1 (baseline) 69 1.0
    1–2 168 1.17 0.97, 1.42 0.109
    3–4 152 1.16 0.89, 1.51 0.283
    5–6 54 1.10 0.84, 1.43 0.480
0.46a
On a typical day during the week this past summer between 10 AM and 4 PM, how many hours did you spend outdoors?
    <1 and 1–2 (baseline) 131 1.0
    3–4 166 1.05 0.87, 1.25 0.632
    5–6 146 1.27 1.05, 1.53 0.014
0.03a
On a typical day during the weekend this past summer between 10 AM and 4 PM, how many hours did you spend at the beach or pool?
    <1 (baseline) 54 1.0
    1–2 143 1.29 1.04, 1.58 0.018
    3–4 172 1.22 1.00, 1.49 0.053
    5–6 74 1.26 1.08, 1.47 0.004
0.02a
On a typical day during the weekend this past summer between 10 AM and 4 PM, how many hours did you spend outdoors?
    <1 and 1–2 (baseline) 142 1.0
    3–4 183 1.15 0.92, 1.44 0.219
    5–6 118 1.33 1.05, 1.67 0.016
0.03a
During the past summer, did you spend time in the sun to get a tan?
    No (baseline) 342 1.0
    Yes 101 1.16 0.93, 1.45 0.178
Did you get a tan on any part of your skin this summer?
    No (baseline) 67 1.0
    Yes 376 1.15 0.95, 1.40 0.151
Did you get a tan on your back this summer?
    No (baseline) 108 1.0
    Yes 335 1.14 0.98, 1.33 0.088
Do you like to get a suntan?
    No (baseline) 210 1.0
    Yes 233 1.04 0.88, 1.22 0.642
How many times did your skin stay red or pink for 12 or more hours, after being out in the sun this past summer?
    None (baseline) 221 1.0
    1 99 1.28 1.01, 1.62 0.044
    2 70 1.22 0.90, 1.67 0.202
    3–4 and ≥5 53 1.23 0.96, 1.58 0.102
0.13a
How many times did you get a painful sunburn this past summer?
    None (baseline) 286 1.0
    1 110 1.33 1.01, 1.76 0.043
    2 and 3–4 and ≥5 47 1.49 1.11, 2.01 0.009
0.005a
How many times did your back stay red or pink for 12 or more hours, after being out in the sun this past summer?
    None (baseline) 273 1.0
    1 107 1.24 1.03, 1.49 0.024
    2 and 3–4 and ≥5 63 1.22 0.98, 1.52 0.071
0.03a
How many times did you get a painful sunburn on your back this past summer?
    None (baseline) 322 1.0
    1 87 1.21 0.90, 1.63 0.204
    2 and 3–4 and ≥5 34 1.32 0.94, 1.85 0.113
0.08a

Abbreviation: CI, confidence interval.

a

Trend-test P value.