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Location and Vitamin D synthesis: Is the hypothesis validated by geophysical data?

Paper ID Volume ID Publish Year Pages File Format Full-Text
31032 44532 2007 6 PDF Available
Title
Location and Vitamin D synthesis: Is the hypothesis validated by geophysical data?
Abstract

The literature reports strong correlations between UV exposure and latitude gradients of diseases. Evidence is emerging about the protective effects of UV exposure for cancer (breast, colo-rectal, prostate), autoimmune diseases (multiple sclerosis, type II diabetes) and even mental disorders, such as schizophrenia. For the first time, the available levels of vitamin D producing UV or “vitamin D UV” (determined from the previtamin D action spectrum) and erythemal (sunburning) UV from throughout the USA are measured and compared, using measurements from seven locations in the USA are measured and compared, using measurements from seven locations in the US EPA’s high accuracy Brewer Spectrophotometer network. The data contest longstanding beliefs on the location-dependence and latitude gradients of vitamin D UV. During eight months of the year centered around summer (March–October), for all sites (from 18°N to 44°N latitude) the level of vitamin D UV relative to erythemal UV was equal (within the 95% confidence interval of the mean level). Therefore, there was no measured latitude gradient of vitamin D UV during the majority of the year across the USA. During the four cooler months (November–February), latitude strongly determines vitamin D UV. As latitude increases, the amount of vitamin D UV decreases dramatically, which may inhibit vitamin D synthesis in humans. Therefore, a larger dose of UV relative to erythemal UV is required to produce the same amount of vitamin D in a high latitude location. However, the data shows that at lower latitude locations (<25°N), wintertime vitamin D UV levels are equal to summertime levels, and the message of increasing UV exposure during winter is irrelevant and may lead to excessive exposure. All results were confirmed by computer modeling, which was also used to generalize the conclusions for latitudes from 0° to 70°N. The results of this paper will impact on research into latitudinal gradients of diseases. In particular, it may no longer be correct to assume vitamin D levels in populations follow significant latitude gradients for a large proportion of the year.

Keywords
Vitamin D; Ultraviolet radiation
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Location and Vitamin D synthesis: Is the hypothesis validated by geophysical data?
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 86, Issue 3, 1 March 2007, Pages 234–239
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us