Pigmentary Characteristics, UV Radiation Exposure, and Risk of Non–Hodgkin Lymphoma: a Prospective Study among Scandinavian Women

Abstract

UV radiation and pigmentary characteristics may be associated with non-Hodgkin lymphoma (NHL) risk, but few prospective studies exist. We investigated these associations in a Norwegian-Swedish cohort. The cohort included women ages 30 to 50 years at enrolment in 1991 to 1992. Host factors, and exposure to sun and artificial tanning devices in life-decades 0 to 50 years were collected by questionnaire. Relative risks (RR) with 95% confidence intervals (CI) were estimated by Poisson regression. Among 104,953 women with complete follow-up through 2006 (Sweden) and 2007 (Norway), 158 were diagnosed with NHL. Women with brown hair had an increased risk of NHL compared with dark brown-haired/black-haired women (RR, 1.72; 95% CI, 1.08-2.74); decreased risks were found among women with gray, green or mixed (RR, 0.50; 95% CI, 0.32-0.77), or blue (RR, 0.54; 95% CI, 0.35-0.81) eyes compared with those with brown eyes, and among those with high propensity to burn compared with those with low propensity (RR, 0.57; 95% CI, 0.36-0.91). Annual number of sunburns and bathing vacations in any age decade, or ever use of artificial tanning devices were not significantly associated with NHL risk. After exposure at ages 10 to 39 years, RRs for ever versus never exposed were 0.99 (95% CI, 0.65-1.50) for sunburn, 1.00 (95% CI, 0.64-1.54) for bathing vacations, and 0.99 (95% CI, 0.67-1.46) for artificial tanning device use. Whereas several pigmentary characteristics were associated with NHL risk, our results do not support an association between UV radiation and NHL. Studies of UV radiation and NHL are warranted for etiologic understanding and public health recommendations.