Multiple myelomaExposure to sunlight

Two ecological studies reported inverse correlations between indices of solar ultraviolet-B (UVB) doses and incidence and/or mortality rates of multiple myeloma (MM).

One in the United States found a 10-20% increased risk of MM for those living in higher latitudes versus those living in lower latitude1.

Inspection of the Atlas of Cancer Mortality in the United States2 indicates that the latitudinal variation is not very strong and that some of the latitudinal gradient might be due to use of agricultural pesticides.

A meta-analysis of MM found about a 20-30% increased risk for farmers compared to nonfarmers3. Thus, this ecological study may have results confounded by an unmodeled risk factor. 

An ecological study in Spain using non-melanoma skin cancer mortality rates by province as the index of solar UVB irradiance found an inverse correlation after adjustment for smoking4. However, as one of very few ecological studies to find such a relation, it cannot be considered strong evidence of a causal link.

A study from the California Teachers Study cohort found  a reduced risk of MM for those living in the region of highest solar UV regions (RR for maximum UVR=0.57, 95% CI=0.36-0.90)5.

Page last edited: 18 July 2011


  1. Boscoe, F. P. Schymura, M. J. Solar ultraviolet-B exposure and cancer incidence and mortality in the United States, 1993-2002. BMC Cancer. 2006; 6264.
  2. Devesa, S. S. Grauman, D. J. Blot, W. J. Pennello, G. A. Hoover, R. N. Fraumeni, J. F. Jr. Atlas of Cancer Mortality in the United States, 1950-1994. NIH Publication No. 99-4564. 1999 November 8, 2008;
  3. Khuder, S. A. Mutgi, A. B. Meta-analyses of multiple myeloma and farming. Am J Ind Med. 1997 Nov; 32 (5): 510-6.
  4. Grant, W. B. An ecologic study of cancer mortality rates in Spain with respect to indices of solar UVB irradiance and smoking. Int J Cancer. 2007 Mar 1; 120 (5): 1123-8.
  5. Chang, E. T. Canchola, A. J. Cockburn, M. Lu, Y. Wang, S. S. Bernstein, L. Clarke, C. A. Horn-Ross, P. L. Adulthood residential ultraviolet radiation, sun sensitivity, dietary vitamin D, and risk of lymphoid malignancies in the California Teachers Study. Blood. 2011 May 26;