Before you roll your car windows and set out on a summer road cruise, consider this: People in the US are more likely to get skin cancer on their left side, perhaps because of driving, new research shows. While driving, the left arm gets more UV. In cases where skin cancer occurred on only one side, 52% of melanomas and 53% of merkel cell carcinomas were on the left, USA Today reports.
The difference was even more marked on upper arm merkel cell carcinomas: 55% of those were on the left side. Other research has shown similar results; in Australia, where people drive on the opposite side of the road, precancerous growths were more common on the right side in a 1986 study. Fortunately, there’s an easy solution: Keep your window rolled up, as the glass will block most of the worst UV rays, or wear sunscreen. (Speaking of which: Click to find out why you can no longer call it sunblock.)