The agony of evidence

Can Fam Physician. 2011 January; 57(1): 16–20.
PMCID: PMC3024150

N.J. Bosomworth, MD CCFP FCFP
Clinical Instructor in the Department of Family Practice at the University of British Columbia in Vancouver
Correspondence: Dr N.J. Bosomworth, 3413 Forsyth Dr, Penticton, BC V2A 8Z2; e-mail john.bosomworth at interiorhealth.ca

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Neither set of recommendations account for Obesity, skin color, time of year, vegetarian eating, lactose intolerant, different dose/responses between individuals, etc.

Comment by Dr. N. John Bosomworth, MD, CCFP, FCFP Jan 2011:

The article was a commentary in the Canadian Family Physician. This category is often more of an editorial or opinion piece and always carries a disclaimer by the journal that the content is not necessarily the opinion of the editorial board. At the same time, the content is carefully peer reviewed before publication, and the information is meant to be presented to the average GP as sound science garnished with a bit of opinion. This particular article is more evidence-based than most commentaries, and does reflect the opinion of most docs working in the field. The only official buy-in so far is from the Pediatricians, who still see rickets in our northern populations. The average doc is starting to take note of these recommendations, but it comes only with repeated exposure to opinions like mine, backed up with some science.

These recommendations can be safely made for individual patients.The Institute of Medicine recommendations are made on a population, rather than an individual basis. Such recommendations tend to be conservative, and rigidly evidence-based. As you know, the evidence is often lacking because there is no money to be made in marketing Vit D. Since there is very little toxicity, there is no down side to recommending what most of us regard as adequate doses, but that seems to be the way the system works with the IOM. I was particularly troubled that Canada adopted the same recommendations, given our additional latitude handicap. Still - a small improvement in the right direction. Unlikely that we will notice any benefit on a population basis - or that anyone will undertake a decent study to measure that benefit.

See also Vitamin D Life

• Overview of How Much Vitamin D chart shows what diseases decrease vitamin D
• All items HOW MUCH D
• All items in Deficiency of D
• 90% of Canadian youth less than 30 ng vitamin D – Oct 2010
• Canadians losing yet another free medical test - vitamin D Nov 2010
• 6th Canadian province may stop paying for vitamin D testing – Sept 2010 Ontario - and summarize others
• Many vitamin D articles by Schwalfenberg in Canada - 2010 good charts and tables
• All items in category Far from Equator 100 items Jan 2012
• Half of Quebec kids had less than 20 ng of vitamin D – Milk and movement did not help – Mar 2011
• Canadian Vitamin D deficiency – May 2011
• Vitamin D insufficiency in UK youths – 37X more likely if dark skin – July 2011 most likely dark skin in Canada as well
• Dark Skinned youths and vitamin D in Southern Canada - Dissertation 2011
• Economic burden of premature deaths due to vitamin D de?ciency in Canada PDF
• Overview of Vitamin D Wiki for Fraser Health (Canada) - Nov 2011 giving 20,000 IU of vitamin D weekly in senior facility