PATHOLOGY

Detailed explanation-1: -Skin pigmentation, i.e., melanin, absorbs the UVR that initiates vitamin D synthesis, and hence decreases the vitamin D that is made for a given exposure compared to less pigmented skin. This has been observed in UVR intervention studies [7] and more generally.

Detailed explanation-2: -Scientists have found that differences in skin color are most highly related to geographic latitude and average dose of UV radiation (UV-R), allowing for selection of dark skin in equatorial regions of the world and light skin at the poles.

Detailed explanation-3: -Indigenous populations in low-UV environments tend to have lighter skin tones. One hypothesis is that, in low-UV environments, the selective pressure for dark skin is low. Instead, there is selective pressure for lighter skin, which absorbs more UV radiation, since UV is needed for vitamin D production.