Journal of Clinical & Experimental Dermatology Research
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Letter to the Editor: Association between Vitamin D Deficiency and Psoriasis: Perspectives of Faculty of Community Medicine and Biochemistry

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Letter to the Editor

We were pleased to read the article entitled “Association between Vitamin D Deficiency and Psoriasis: A Case-Control Study” published in your journal “Journal of Clinical & Experimental Dermatology Research,” in the Volume 9 (Issue 2) of 2018 [1]. Vitamin D deficiency is one of the problems of modern era. It is many times quoted as associated with psoriasis and further contributing to its morbidity. The above mentioned article is quite relevant as per the regional and global need. Hence the objective of our writing this letter was to understand the salient findings of the article and discuss relevant concerns.

The objective of the study is clear and as mentioned in the study1 was to demonstrate the association between psoriasis and serum levels of vitamin D (25- hydroxycalciferol [25(OH)D]). The study was nicely designed. The socio-demographic characteristics of the study participants were similar and there was no statistically significant difference between the groups. This was one of the strengths of the study as the variable of interest could be well compared. No significant difference between the cases and controls was found in the study as regards body mass index (BMI) of the two groups. This was again a positive finding reflecting minimal selection bias. Data analysis was also explained nicely. Authors made good efforts in communicating detailed information regarding the various issues as in, the sun exposure and the medications used by the cases and controls.

Also, looking at table 4 of the article [1], it could be drawn that there was very less possibility of selection bias in the study. We would like to further mention that there was inadvertent printing error regarding cases of diabetes in the table 4. Although, chi statistic has been mentioned in the table. The various studies showing association of vitamin D deficiency and those showing no association of vitamin D deficiency with psoriasis has been discussed and the possible reasons of such variations have been nicely explained. Under the discussion, the study of Gisondi et al (2012) [2] was quoted which probably showed that in psoriasis patients, vitamin D deficiency was 2.5 times more common.

Additionally, the exclusion and inclusion criteria were well defined to take care of the possible selection bias. One of the criteria for exclusion was the previously diagnosed cases of vitamin D deficiency.
It was well considered by the investigators because such subjects might have been taking the respective treatments and could result in selection bias. From another point of view, we would like to add that we believe probably the criteria of vitamin D supplements intake could have been even a better exclusion criteria than the mere diagnosis. In case further studies on the topic are planned, for applying the findings in different setups, it would be helpful for the readers to know the technology used for estimation of vitamin D levels and the quantification units including the cut off levels. We appreciate and congratulate the authors for conducting a nice study and contributing on this important aspect. We hope further studies on the topic are conducted in various populations from different regions.

With due regards,

Authors

References

1. Allayali A, Niaz G, Hawsawi KA, Fatani M, Siddiqui I, Baghdadi R, et al. Association between Vitamin D Deficiency and Psoriasis: A Case- Control Study. J Clin Exp Dermatol Res. 2018;9:442.
2. Gisondi P, Rossini M, Di Cesare A, Idolazzi L, Farina S, Beltrami G, et al. Vitamin D status in patients with chronic plaque psoriasis. Br J Dermatol. 2012;166:505-510.