Racial disparities for uterine corpus tumors

The recent paper by Wright et al 1 found that black women were 60% more likely to die from their corpus uteri tumors than white women when matched for other prognostic variables. A factor overlooked in this study was the role of vitamin D. Solar ultraviolet B (UVB) and vitamin D have been found inversely correlated with many types of cancer, including corpus uteri. In an ecological study of cancer mortality rates for white Americans, which included indices for various cancer risk factors, 14 types of cancer including uterine corpus and breast cancer were found inversely correlated with summertime solar UVB doses. 2 Solar UVB was also found inversely correlated with breast and several other types of cancer for black Americans.3 There is sufficient evidence regarding the mechanisms and from 1 randomized controlled trial that the vitamin D-cancer link can be considered causal.4 Because breast and corpus uteri cancer mortality rates have similar geographic variations in the United States, 2 the study of disparities in breast cancer survival can be investigated to consider whether differences in vitamin D status might affect corpus uteri cancer survival rates. In a recent publication,5 it was noted that black Americans have much higher rates of hypovitaminosis D prevalence; that those diagnosed with breast, colon, or prostate cancer or Hodgkin lymphoma in summer or fall in Norway have better 36-month survival rates than those diagnosed in winter or spring; and that a randomized controlled trial involving postmenopausal women living in Nebraska found a 35% reduction in all-cancer incidence for those taking 1100 IU/day of vitamin D.5 The author receives funding from the UV Foundation (McLean, Va), the Vitamin D Society (Canada), the Sunlight Research Forum (Veldhoven, the Netherlands), and Bio-Tech-Pharmacal (Fayetteville, Ark). William B. Grant PhD*, * SUNARC, San Francisco, California.