Fewer cases of melanoma were observed in people who regularly used vitamin D supplements compared to those who took them occasionally or never, according to a new study conducted by the University of Eastern Finland in collaboration with Kuopio University Hospital.  
 
The study, which recruited nearly 500 people who had an elevated risk of skin cancer, appeared in Melanoma Research.
 
Vitamin D has been studied in connection to skin cancers for many years, but most clinical research has looked specifically at serum calcidiol, which does not provide accurate information on the metabolism of vitamin D within the human skin.
 
The new study took a different approach by recruiting 498 adults estimated to have an increased risk of skin cancers including basal cell carcinoma, squamous cell carcinoma, and melanoma from an outpatient clinic at Kuopio University Hospital.
 
Dermatologists at the University of Eastern Finland analyzed patients’ background information and medical history and examined their skin to classify patients into different skin cancer risk classes. Based on their use of vitamin D supplements, patients were divided into either non-user, occasional user, or regular user groups. Serum calcidiol levels were measured in half of the patients and were found to correspond with self-reported supplement use.
 
There were significantly fewer cases of past or present melanoma in patients who were regular users of vitamin D versus non-users (18.1% versus 32.3% respectively). The findings also suggested that even occasional users of vitamin D may have a lower risk for melanoma than non-users, though the association wasn’t statistically significant.
 
There were no statistically significant links between vitamin D use and the severity of photoaging, facial photoaging, actinic keratoses, nevus count, basal cell carcinoma, and squamous cell carcinoma. Serum calcidiol levels weren’t linked with skin changes either.
 
Earlier studies have also established a link between vitamin D and melanoma.
 
“These earlier studies back our new findings from the North Savo region here in Finland. However, the question about the optimal dose of oral vitamin D in order for it to have beneficial effects remains to be answered. Until we know more, national intake recommendations should be followed,” said Ilkka Harvima, professor of dermatology and allergology at the University of Finland.
 
Melanoma rates are particularly high in the North Savo region where the study took place, noted Harvima. “For this reason, too, it is worth paying attention to sufficient intake of vitamin D in the population in this region.”