The study tracks lung cancer rates in 111 countries. Lung cancer rates were lower in countries along the equator than in countries far from the equator.
The pattern held regardless of the countries' smoking statistics, note the researchers, who included Sharif Mohr, MPH, of the University of California, San Diego's department of family and preventive medicine.
But the findings don't mean that moving to the tropics (or ditching your sunscreen) will prevent lung cancer.
Mohr and colleagues looked at the big picture -- national and international trends -- but not at individual risk. They didn't test sunshine, ultraviolet light, or vitamin D for lung cancer prevention -- and they couldn't control for all possible influences on the data.
Their report appears in January's edition of the Journal of Epidemiology and Community Health.