Table 3.

RRs and 95% CIs of NHL according to annual number of weeks per year spent on bathing vacations in southern latitudes or within Norway or Sweden in successive decades of life

Age period and no. of bathing vacationsNo. of casesAge-adjustedMultivariate*
RR (95% CI)RR (95% CI)
<10 y (n = 46,287)
    0711.001.00
    ≥1 wk/y241.14 (0.72-1.82)1.12 (0.70-1.79)
P = 0.57P = 0.65
10-19 y (n = 90,450)
    0731.001.00
    1 wk/y160.58 (0.34-1.00)0.67 (0.38-1.16)
    ≥2-3 wk/y441.14 (0.78-1.66)1.24 (0.84-1.82)
Ptrend = 0.69Ptrend = 0.38
20-29 y (n = 92,946)
    0411.001.00
    1 wk/y431.09 (0.71-1.68)1.19 (0.77-1.84)
    ≥2-3 wk/y611.12 (0.75-1.66)1.16 (0.77-1.73)
Ptrend = 0.59Ptrend = 0.51
30-39 y (n = 90,806)
    0341.001.00
    1 wk/y411.04 (0.66-1.64)1.06 (0.67-1.68)
    ≥2-3 wk/y681.21 (0.80-1.82)1.17 (0.77-1.77)
Ptrend = 0.34Ptrend = 0.45
40-49 y (n = 43,459)
    0241.001.00
    1 wk/y241.05 (0.60-1.85)1.10 (0.62-1.94)
    ≥2-3 wk/y421.25 (0.76-2.07)1.26 (0.76-2.11)
Ptrend = 0.36Ptrend = 0.36
Combined, 10-39 y (n = 85,667)
    0, 10-39 y261.001.00
    ≥1/y, 10-39 years1050.96 (0.63-1.48)1.00 (0.64-1.54)
P = 0.87P = 0.98

NOTE: Poisson regression analysis. All statistical tests were two-sided. Bathing vacations at age <10 years were only recorded for the Norwegian women. Analyses of bathing vacations at ages 40 to 49 years included only women ≥40 years when answering the questionnaire.

  • *Multivariable models included attained age, region of residence, hair color, eye color and skin color after heavy sun exposure in the beginning of the summer and after repeated sun exposure.