Lack of exposure to sunlight may increase the risk of lung cancer, a study of 111 countries shows. Smoking is the risk factor most closely associated with the disease, accounting for as many as 85% of cases, but limited access to UV rays is second, the Telegraph reports. Vitamin D, which is generated by exposure to the sun, can slow or even halt tumor growth, reports the BBC.
Countries closer to the equator exhibited lower rates of lung cancer than countries farther away, whose residents have fewer hours of sun exposure. Vitamin D stimulates the release of chemicals that, when combined with calcium, can bind cells more tightly and slow the explosion of cell division that results in cancer. But sun exposure is no panacaea: Too much boosts the risk of skin cancer.