Question about Vitamin D Serum Levels

[Guide]

A new report concluded "that increased vitamin D levels may lead to the development of rosacea." Here is a link to the report:

http://www.ncbi.nlm....8?dopt=Abstract

The report is odd in that it shows that both the rosacea patients and the control group both showed Vitamin D deficiencies. The rosacea patients showed higher levels of Vitamin D than the control group.

The report states:

"Deficiency of vitamin D is defined as the level of 25(OH)D being less than 20 ng/ml."

And this statement:

"The mean levels of vitamin D levels were found as 21.4 ± 9.9 and 17.1 ± 7.9 in patients and controls, respectively."

And this statement:

"The prevalence of vitamin D deficiency in patients with rosacea was 38.6% and 28.1% in healthy controls (p = 0.34)."

So if I am reading this correctly, the last statement shows that 38% of the rosacea group were deficient in Vitamin D while only 28% of the control group were deficient. 61% of the rosacea group have no deficiency of Vitamin D while 71% of the control group have no deficiency of Vitamin D Serum levels.

Why does the report conclude that "increased vitamin D levels may lead to the development of rosacea?"

Also, increasing Vitamin D in both groups was never studied to see if the rosacea gets worse or better. Would increasing Vitamin D in the serum be a good idea to see if rosacea gets better or worse?

Can any of the MAC members please comment on this study?

http://www.ncbi.nlm....8?dopt=Abstract

[Guest]

Received one reply from Husein Husein-ElAhmed MD by email who wrote the following:

Dear members,

Here there are the comments on the study:

First of all this is a preliminary and very simple study comparing the serum levels of vitamin D levels between rosacea patients and controls, therefore any valid conclusion should be taken very carefully.

As the authors stated, vitamin D deficiency has been associated with other immune-mediated cutaneous diseases such as psoriasis, vitiligo and atopic dermatitis. While in rosacea, immune system as a role, this is not the basis of the disease, so that, the plausibility of the study should be, again, taken carefully.

FIRST CONCLUSION: The biological plausibility of the study is questionable.

The report states that: "The difference was statistically significant (p = 0.04). The prevalence of vitamin D deficiency in patients with rosacea was 38.6% and 28.1% in healthy controls (p = 0.34)". In medical statistics, the difference between two groups (e.g. patients with rosacea versus controls) is considered significant (which means not the difference is realiable, and not due to random fluctuations) when the "P" value is < 0.05. The authors in this study have performed two statistical tests: the significance was obtained only in one of them, but not confirmed in the other. Furthermore, no multivariable analysis was performed.

SECOND CONCLUSION: The statistic test used in this study is not conclusive and are incomplete.

The sample size in this study is too short ( 44 patients and 32 controls) to make any strong conclusion to be generalized.

THIRD CONCLUSION: The power of this study is weak.

As you can see, this study has too many deficiences, so that, the results obtained should be considered carefully.

Responding to the answer of the poster,

1. The conclusion of the report regarding that: "... increased vitamin D levels may lead to the development of rosacea..." is wrong, or at least, it can't be obtained from the findings of this study.

2. I don't think increased levels of vitamin D may have any effect on rosacea ( worsening or improving). However, this question can only be answered with the ongoing medical researches.

Hope you find my comments useful.

Regards,

Husein Husein-ElAhmed MD