Association between Ambient Ultraviolet Radiation and Risk of Epithelial Ovarian Cancer

Abstract

Evidence is accumulating to suggest that higher exposure to solar ultraviolet radiation (UVR) is associated with decreased risk of internal cancers, but data for ovarian cancer are unclear. We aimed to examine the association between lifetime ambient UVR and ovarian cancer in a population-based-casecontrol study. The study included women aged 18 to 79 years with a new diagnosis of invasive (n ¼ 1,215) or borderline (n ¼ 285) epithelial ovarian cancer identified through a network of clinics and state cancer registries throughout Australia. Controls (n ¼ 1,459), frequency matched to cases by age (5-year groups) and state of residence, were randomly selected from the National Electoral Roll. We asked participants to report where they had lived at different periods of their life and assigned an estimate of UVR using data from NASA's Total Ozone Mapping Spectrometer database (1997)(1998)(1999)(2000)(2001)(2002)(2003). We estimated the association between ambient UVR and risk of ovarian cancer using conditional logistic regression adjusted for potential confounders. Women in the highest third of average daily ambient UVR over their lifetime were at significantly lower risk of all epithelial ovarian cancers than those in the lowest third [OR, 0.70; 95% confidence interval (CI), 0.56-0.88]. The inverse association was stronger for borderline tumors (0.47, 0.31-0.71) than invasive tumors (0.78, 0.61-1.00). The effect sizes for overall and borderline tumors were unchanged after adjusting for confounders, whereas the inverse association for invasive tumors was attenuated. These data suggest that exposure to ambient UVR may reduce the risk of ovarian cancer. Cancer Prev Res; 5(11); 1330-6. Ó2012 AACR.

Review of Recent Advances in Understanding the Role of Vitamin D in Reducing Cancer Risk: Breast, Colorectal, Prostate, and Overall Cancer

“…Ecological studies treat populations in geographically defined regions as entities and use statistical methods to compare disease outcomes averaged for each region, with risk-modifying factors also averaged for each region. For cancer, incidence or mortality rates are compared with indices for vitamin D production that can be annual solar radiation dose (1), summertime UVB dose (2,3), or latitude in countries with flat terrain (4). Because many factors affect cancer risk, values for other risk-modifying factors should also be used.…”

Temporal Trends in Satellite-Derived Erythemal UVB and Implications for Ambient Sun Exposure Assessment

“…TOMS and OMI UVR estimates have been previously used to estimate sun exposure in various epidemiological studies including those focused on multiple sclerosis [16], cancer [23,24,25,26,27,28,29,30], asthma and hayfever [31], diabetes [32], and mortality [33,34]. Many of these studies assumed no long-term changes in UVR, and simply averaged UVR to estimate sun exposure.…”

“…Unlike ground level instruments, the satellite data provide continuous standardized estimates across the globe which allows for study of UVR exposures outside of the US. Satellite data have been used in the study of various health outcomes including multiple sclerosis [16], melanoma [21,22,23] and other cancers [24,25,26,27,28,29,30], asthma and hayfever [31], diabetes [32], and mortality [33,34]. Although satellite data represent an opportunity for standardized UVR estimation across vast distances many criticisms for use of this source exist, such as data validation and seasonal inconsistencies [35].…”

Surrogates of Long-Term Vitamin D Exposure and Ovarian Cancer Risk in Two Prospective Cohort Studies

“…The association appeared stronger for women diagnosed with borderline tumors (OR = 0.51; 95% CI: 0.32, 0.81) and displayed similar ~25% to 30% decreased risks for invasive serous, mucinous, and endometrioid tumors [21]. While we observed a reduced risk of serous tumors in the younger NHSII cohort for women living in areas of higher UV-B flux, UV-B flux was not associated with mucinous or endometrioid/clear cell tumors.…”

“…A recent systematic review of the literature concluded that individual-level epidemiologic studies have not been successful in clarifying the relationship between vitamin D exposure and ovarian cancer risk in part due to variability in study design, exposure assessment or range, and outcome definition [19]. Etiologic heterogeneity by ovarian cancer histologic subtypes [20] or tumor invasiveness [21] also may contribute to the inconsistent results, or the association between vitamin D exposures and ovarian cancer risk may be limited to subgroups of the population [20,22]. …”