For instance, the average sun worshipper applies less than half of the amount of sunscreen used in SPF rating tests and spreads it unevenly, missing the full benefit of the lotion. Paradoxically, many people who use sunscreen don’t reduce, but actually increase their exposure, lulled by a false sense of invulnerability into staying out longer in the sun or during midday hours when cancer-causing UV radiation is at its highest.

One European study comparing the SPF 10 with SPF 30 sunscreen found that subjects using the more protective formula went out in the sun earlier in the day and stayed out longer, resulting in no overall decrease in sunburns.

“The important message is that the total ultraviolet burden is the key, since the same dose over a longer time is more damaging,” said Antony R. Young, Ph.D., of King’s College in London. He recommended using a broad spectrum sunscreen to block both UVB and UVA radiation, and reapplying sunscreen more frequently in the course of the day.

Marianne Berwick, Ph.D., M.P.H., of Memorial Sloan-Kettering Cancer Center in New York agreed, advising people to use sunscreen but not rely on it. “We ought to find more ways as a society to make shade for people to work and play in,” she said.

For Webcast audio and video of some of the meeting’s presentations, go to here.

— Aaron Levin, Health Behavior News Service