Lack of Sunny Holidays in Northern Latitudes Linked to Low Vitamin D Interview with:
Ms Emily Weiss PhD student
Centre for Population Health Sciences
The University of Edinburgh What is the background for this study? What are the main findings? 

Response: Vitamin D deficiency, a marker of low ultraviolet (UV) exposure, is common in Scotland; both have been shown to work independently as risk factors for multiple sclerosis (MS). Orkney, situated to the north of mainland Scotland has a very high prevalence of MS. We therefore wanted to understand how vitamin D in Orkney compares to mainland Scotland’s vitamin D, and also what may be determining vitamin D levels in Orkney. What should clinicians and patients take away from your report? 

Response:  Whilst we have shown that the mean level of vitamin D is lower in mainland Scotland than Orkney, the reasons for this are that there are significantly more severely deficient people in mainland Scotland which lowers their mean level and raises Orkney’s mean level in comparison. In both groups of people, the vast majority were below what we considered to be ‘sufficient’ in vitamin D.

However, what was interesting to find was that while vitamin D levels in mainland Scotland decreased by decade of age as we would expect, in Orkney vitamin D levels actually increased as people age. The reasons for this are that people over 50 are taking more foreign holidays than people under 50, and that the farmers we had in our cohort had significantly higher vitamin D levels than non-farmers, likely because of greater-than-average time spent outside, and they also tended to be older.

What this means is that the younger population, at an age at which  multiple sclerosis is more often diagnosed, are more likely to be vitamin D deficient and less exposed to UV radiation from sunshine than the older population. What recommendations do you have for future research as a result of this study?

Response:  Further research will focus on Shetland, the most northerly UK county, which also has a very high prevalence of MS. Understanding what may determine individual UV exposure, and how that translates to vitamin D, would help us to understand how the sun, or lack thereof, in these high latitude islands may be affecting the population.


Emily Weiss, Lina Zgaga, Stephanie Read, Sarah Wild, Malcolm G. Dunlop, Harry Campbell, Ruth McQuillan, James F. Wilson. Farming, Foreign Holidays, and Vitamin D in Orkney. PLOS ONE, 2016; 11 (5): e0155633 DOI: 10.1371/journal.pone.0155633

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on May 19, 2016 by Marie Benz MD FAAD