A new study has pointed out that vigilance against skin cancer can cause vitamin D deficiency.
Patients with basal cell nevus syndrome-which might lead to non-melanoma skin cancers-are at a higher risk for vitamin D deficiency if they take steps to protect themselves from sunlight.
"There is increasing concern that sun protection, recommended by dermatologists to prevent further UV damage in populations susceptible to skin cancer, may result in abnormally low levels of 25-hydroxyvitamin D [25(OH)D, a blood measure of vitamin D levels], which may have subsequent detrimental effects on health," wrote the authors.
Jean Y. Tang of Stanford University Medical Center and colleagues studied 41 patients with basal cell nevus syndrome, who are genetically predisposed to develop basal cell carcinomas.
Patients with basal cell nevus syndrome generally try to prevent skin cancers by using sunscreen and avoiding the sun during peak hours.
The 41 patients had blood drawn an average of three times during the two-year study; 23 (56 percent) were vitamin D deficient.
When compared with the general population, patients with basal cell nevus syndrome had lower average vitamin D levels.
Blood vitamin D levels were lower among patients with basal cell nevus syndrome who were overweight, and in those who had blood collected in the winter compared with the summer.
Among 35 patients with basal cell nevus syndrome who completed a survey, 28 (80 percent) reported using sunscreen daily and most reported avoiding sunshine.
"It may not be surprising that patients with a genetic predisposition to sun-induced cancers report a high frequency of photoprotection and may be vitamin D deficient," said the authors.
"However, the magnitude of this deficiency and the possible additive effect of obesity, which is common in these patients, make individuals with basal cell nevus syndrome optimal candidates for cholecalciferol supplementation," they said.
The findings were published in the Archives of Dermatology, one of the JAMA/Archives journals.