Low vitamin D in high latitude Minnesota  2009
Minn Med. 2009 Nov;92(11):43-6.
Weather or not: the importance of vitamin D status monitoring and supplementation.
Plotnikoff GA.
Penny George Institute for Health and Healing, Abbott Northwestern Hospital, USA.
The Centers for Disease Control and Prevention's latest data show markedly high prevalence rates of severe vitamin D deficiency among Americans of all ages. Because of the numerous negative health consequences associated with vitamin D deficiency, we must consider all potential causes including insufficient exposure to the sun's ultraviolet B radiation. This article presents data from the National Weather Service that documents how few days in Minnesota offer the opportunity to make vitamin D. Thus, even Minnesotans who spend a significant amount of time outdoors and consider themselves to have sufficient sun exposure may still be at risk for vitamin D deficiency. This is especially true for the elderly, those with high melanin content in their skin, and those with a higher body mass index, all of whom require significantly more sun to achieve adequate levels of vitamin D. Given the lack of sufficient ultraviolet B radiation people in Minnesota get from the sun between October and April, measurement of vitamin D status is required for rational replenishment and maintenance dosing. The goal of replenishment should be at least 32 ng/mL and, ideally, more than 50 ng/mL.
PMID: 20069998 [PubMed - in process]