The authors used death certificates to glean the numbers of deaths from 5 cancers between 1984 and 1995, across 24 US states.
They aimed to assess the impact of residential and occupational exposure to sunlight on the likelihood of dying from breast, ovarian, colon, prostate, and skin cancer.
As expected, the authors found that there were higher numbers of deaths from skin cancer, the sunnier the area of residence.
|Sunlight reduced deaths from following cancers:|
| Occupational and Environmental Medicine |
However, death from the other 4 cancers was significantly lower in very sunny climates.
Working outdoors in a very sunny environment was also associated with fewer deaths from breast and colon cancer. The geographical areas of greatest sunlight showed the strongest relationship.
This finding was independent of the amount of physical activity required for the job.
The risk of death from all cancers, except skin cancer, grew stronger with increasing socioeconomic status.
The authors cite research which has suggested a plausible explanation for the protective effect of sunlight.
Laboratory experiments show that vitamin D seems to retard the speed of cancer cell division, including breast and colon cancer cells.