Taking calcium supplements reduces risk of squamous cell carcinoma

Treatment with calcium supplementation with or without vitamin D appears to lower the risk of invasive cutaneous squamous cell carcinoma (SCC) but not basal cell carcinoma (BCC), a study has shown.

The investigators sought to determine whether daily vitamin D or calcium supplementation modifies the risk of BCC or SCC in this multicentre, double-blind, placebo-controlled, partial two-by-two factorial, randomized clinical trial of vitamin D, calcium, or both for the prevention of colorectal adenomas.

A total of 2,259 men and women aged 45–75 years, who were diagnosed with a colorectal adenoma from 2004 to 2008 were randomized to receive 1,000 IU/d of vitamin D₃ or placebo and 1,200 mg/d of calcium carbonate or placebo for 3 or 5 years. Participants were followed when treatment ended. Pathology records were used to confirm reports of incident BCC or SCC.

Of the participants, 200 (9 percent) were diagnosed with BCC and 68 (3 percent) with SCC during a median follow-up of 8 years.

BCC incidence was not associated with vitamin D treatment compared with no vitamin D (hazard ratio [HR], 0.96, 95 percent confidence interval [CI], 0.73–1.26), calcium compared with no calcium (HR, 1.01, 95 percent CI, 0.74–1.39), and both agents compared with neither (HR, 0.99, 95 percent CI, 0.65–1.51).

SCC incidence, on the other hand, was not associated with vitamin D treatment compared with no vitamin D (HR, 0.79, 95 percent CI, 0.49–1.27), but there appeared to be beneficial effects for calcium compared with no calcium (HR, 0.60, 95 percent CI, 0.36–1.01) and both agents compared with neither (HR, 0.42, 95 percent CI, 0.19–0.91).