[Spartan79]

Surprisingly, this article and none of the commenters brought up the other profound benefit of getting vitamin D from moderate sun exposure: cholesterol reduction. The raw material utilized by the body in synthesizing vitamin d is cholesterol; in fact, some people with very low levels of cholesterol cannot adequately synthesize vitamin d (there have been some studies suggesting that people who take statins to reduce cholesterol often have vitamin d deficiencies).

To maximize the benefit of sun exposure, Americans need to modify their hygiene habits. If you get a good dose of sunshine and then promptly step into the shower and thoroughly scrub yourself with soap and water, most of the vitamin d is flushed down the drain. It takes up to 48 hours for the vitamin d produced in the oils on the skin to be absorbed into the body. Just soap up and scrub the "high points" (which probably weren't exposed to the sun anyway, unless you are of the naturalist persuasion) instead of the entire body.

[khnyny]

That’s actually quite interesting. I wonder if they have done studies taking hygiene habits into consideration. The West, especially starting in the 20th Century, has been increasingly meticulous in the pursuit of personal hygiene.

The following stats are very old (1985), but I’m curious as to why Gambia shows such low stats:

http://rex.nci.nih.gov/NCI_Pub_Interface/raterisk/rates25.html

Could it be a combination of: exposure to sunlight, hygiene habits and access to pure food, especially fish?

A lot of stats focus on survival rates, but don’t show number of incidences per population.