By Dr. Dave Hnida

DENVER (CBS4) – Cut the lawn, go for a hike, and head for a swim — most of us automatically smear on sunscreen without much thought.

But how about going for a ride in the car?

According to a new study in the journal JAMA Ophthalmology, our cars may be giving us the burn, and more importantly, and increased risk of skin cancer and cataracts.

It all has to do with the windows, and the amount of UVA rays that sneak in through them — particularly the side windows.

Researchers say windshields are generally protective, since they are made with two layers of glass with a UV protective blocking material in between. But that’s not the case with side windows. Those are single layered, with no UV protection.

The study looked at the UV penetration through windows of 29 makes of automobiles from 15 different manufacturers. Protection was pretty good from the front. The sides, uh, not so good.

So if you’re doing a lot of driving, or a lot of riding, you are getting nailed with potentially harmful UV rays, especially UVA — which is a major skin cancer player. How much does it take? We don’t know … but that’s the same answer we give for everyday sun exposure. We just know it’s a risk.

For example, we have known for some time now that long distance truck drivers tend to have higher rates of skin cancer than the general population because of those long hours of exposure behind the wheel.

How about you? You’ve got to think about it, too, even if you’re not a cross country long hauler. Especially when we look at stats which show more skin cancers on the left side of the face, and more cataracts in the left eye — so it kind of makes sense that years of sun exposure may be to blame.

But don’t forget, spend a lot of time on the passenger’s side, and that window won’t protect you either.

So if you’ve got a long trip (even on a cloudy day), or you spend a lot of time living in your vehicle as you fight traffic day in and day out, those UV rays will add up, and possibly cause some damage.

The answer according to researchers:  think sunscreen, UV protective sunglasses, and even a hat the next time you’re out for a spin.

Dr. Dave Hnida is CBS4’s Medical Editor. He blogs about the latest studies and trends in the health world. Read his latest blog entries, check out his bio or follow him on Twitter @drdavehnida


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