Skin cancer is one of the most common cancers in the U.S. Over a million cases get diagnosed with the disease each year. Researchers from the St. Louis University investigated the correlation between more time spent driving and a higher incidence of left-sided skin cancers and realized that it would be wise to slather on the sunscreen before getting behind the wheel.

The researchers looked at 1,047 skin cancer patients and found that 53% had skin cancer on the left side of the body. They put a special accent on the left arm, left hand, and the left side of the head and neck-places most likely to be exposed while driving.
The higher incidence of the left-sided cancers is thought to be due to ultraviolet (UV) exposure.

The incidence was only reported in men, while the left-sided pattern wasn't seen in women.

The highest chances of developing left-sided skin cancers had light-skin male drivers who spent a lot of time behind the wheel as well as those driving with the window open.

Although most cars have their front windshields blocking the sun's ultraviolet A (UVA) and ultraviolet B (UVB) rays, side and rear windows usually block only UVB rays.

A good prevention would be using UV filters on auto glass as well as having protective clothing and a broad-spectrum sunscreen.