Higher Rates of Lung Cancer in Lower UVB Light Areas
Cigarettes strongest risk factor but lack of vitamin D from sunlight may also play a role
TUESDAY, Dec. 18 (HealthDay News) -- In a survey of 111 countries, places with lower levels of ultraviolet B (UVB) irradiance have higher incidence of lung cancer, according to research published in the January issue of the Journal of Epidemiology and Community Health.
Sharif B. Mohr, of the University of California San Diego in La Jolla, Calif., and colleagues looked at age-adjusted rates of lung cancer to see if there was an independent association with latitude and UVB irradiance, taking into account smoking as well as factors affecting UVB exposure such as cloud cover and anthropogenic aerosols.
There was a positive association between latitude and lung cancer incidence for both men and women. There was an inverse association between lung cancer risk and UVB irradiance and a positive association with smoking. Cloud cover and aerosol optical depth, both UVB absorbers, were positively associated with lung cancer incidence.
"This analysis investigated the role that vitamin D status may play in the remaining 15 to 25 percent of lung cancer incidence not accounted for by cigarette smoking," the authors write. "The principal source of vitamin D is from solar UVB irradiance, which increases with increasing proximity to the equator. Lung cancer incidence rates in men and women were highest in countries at the latitudes most distant from the equator."