Abstract
Dear Editor,
I have read with interest the article “High Prevalence of Vitamin D Deficiency in Patients With Bone Marrow Edema Syndrome of the Foot and Ankle” concerning vitamin D concentrations in patients with bone marrow edema syndrome (BEMS). 2 The authors should be congratulated on being able to collect such a numerous group of patients with this rare entity. I agree with the authors that bone metabolism is an important factor in BEMS and vitamin D may play a role, but the issue of vitamin D concentration in this patient group requires a perspective.
The population living at European latitudes has a high prevalence of vitamin D insufficiency and deficiency. In such a case, any random sample of this population would present low vitamin D status. With no comparison group, it is impossible to know if the observed result indicates a real abnormality or only represents a sampling of the vitamin D–deficient population.
In our study (latitude 52.1°N), vitamin D concentration was compared between patients with non-unions and sex-, age-, and season-matched controls. 1 Observation that 86% of patients with nonunion were vitamin D deficient could have suggested the link between nonunion and vitamin D. What is of note, 86% of control group patients were also vitamin D deficient and the groups did not differ.
Authors should be complemented for trying to use artificial comparison groups, but in my opinion this is methodologically unsound. To give one example, Canada legally requires fortification of food with vitamin D whereas Germany actually prohibits it.
To summarize, observing high prevalence of vitamin D deficiency at our geographical latitude may represent a random sampling of population and does not imply any connection with BEMS.
With kind regards,