Abstract
To lend clarity to inconsistent prior findings of an inverse association between ultraviolet radiation (UVR) exposure and risk of lymphoid malignancies, we examined the association of prospectively ascertained residential ambient UVR exposure with risk of non-Hodgkin lymphomas (NHLs), multiple myeloma (MM), and classical Hodgkin lymphoma in the California Teachers Study cohort. Among 121 216 eligible women, 629 were diagnosed with NHL, 119 with MM, and 38 with Hodgkin lymphoma between 1995-1996 and 2007. Cox proportional hazards regression was used to estimate incidence rate ratios (RRs) with 95% confidence intervals (CIs). Residential UVR levels within a 20-km radius were associated with reduced risk of overall NHL (RR for highest vs lowest statewide quartile of minimum UVR [≥ 5100 vs < 4915 W-h/m(2)], 0.58; 95% CI, 0.42-0.80), especially diffuse large B-cell lymphoma (RR, 0.36; 95% CI, 0.17-0.78) and chronic lymphocytic leukemia/small lymphocytic lymphoma (RR, 0.46; 95% CI, 0.21-1.01), and MM (RR for maximum UVR, 0.57; 95% CI, 0.36-0.90). These associations were not modified by skin sensitivity to sunlight, race/ethnicity, body mass index, or neighborhood socioeconomic status. Dietary vitamin D also was not associated with risk of lymphoid malignancies. These results support a protective effect of routine residential UVR exposure against lymphomagenesis through mechanisms possibly independent of vitamin D.