|Year : 2020 | Volume
| Issue : 3 | Page : 1016-1020
Correlation between vitamin D serum level and severity of psoriasis
Shawky M El-Farargy1, Naglaa M Ghanayem2, Aya M Elrashidy3
1 Department of Dermatology, Andrology and STDs, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
3 Department of Dermatology, Andrology and STDs, Kafr El-Zayat General Hospital, Gharbia, Egypt
|Date of Submission||09-Jan-2019|
|Date of Decision||05-Mar-2019|
|Date of Acceptance||10-Mar-2019|
|Date of Web Publication||30-Sep-2020|
Aya M Elrashidy
Source of Support: None, Conflict of Interest: None
To investigate serum levels of vitamin D in patients with psoriasis compared with healthy controls, and to consider their relation to disease severity.
Psoriasis is a chronic, recurrent, immune-mediated, inflammatory skin disease. Vitamin D is a fat-soluble vitamin that is obtained from food supplements and sun exposure. Vitamin D deficiency has been incriminated in a long panel of diseases including cancers, autoimmune diseases, and cardiovascular and neurological disorders. In psoriasis, vitamin D is involved in the maintenance of cutaneous barrier homeostasis. Several studies have identified an association between polymorphisms of vitamin D receptor and psoriasis susceptibility.
Patients and methods
This case–control study was conducted on 30 patients with chronic plaque psoriasis and 10 age-matched and sex-matched healthy controls during the period from March 2017 to March 2018. All patients were subjected to full history taking, clinical examination, and laboratory investigations. Serum vitamin D levels were measured by using enzyme-linked immunosorbent assay technique.
There is significant decrease in the level of serum vitamin D in moderate (mean ± SD, 27.57 ± 6.96) and severe (mean ± SD, 19.28 ± 6.35) patient groups compared with the control group (mean ± SD, 40.04 ± 11.12) whereas nonsignificant difference existed with the mild group (mean ± SD, 33.28 ± 5.34). There is significant negative correlation between serum vitamin D and each of age (r = −0.418, P = 0.022), disease duration (r = −0.572, P = 0.001), and psoriasis area and severity index score (r = −0.680, P < 0.001).
Decreased 25 OH vitamin D serum level was found in psoriatic patients. The 25 OH vitamin D serum level may be used as a marker of psoriasis severity and response to treatment.
Keywords: enzyme-linked immunosorbent assay, psoriasis, skin disease, vitamin D
|How to cite this article:|
El-Farargy SM, Ghanayem NM, Elrashidy AM. Correlation between vitamin D serum level and severity of psoriasis. Menoufia Med J 2020;33:1016-20
|How to cite this URL:|
El-Farargy SM, Ghanayem NM, Elrashidy AM. Correlation between vitamin D serum level and severity of psoriasis. Menoufia Med J [serial online] 2020 [cited 2020 Nov 26];33:1016-20. Available from: http://www.mmj.eg.net/text.asp?2020/33/3/1016/296705
| Introduction|| |
Psoriasis is a chronic, recurrent, immune-mediated disease of the skin and joints that may affect negatively the physical, emotional, and psychosocial well-being of affected patients . Indeed, nowadays psoriasis is considered a systemic pathology, including also other conditions, from psoriatic arthritis to obesity and metabolic disease, which increased cardiovascular risk in psoriatic patients . Psoriasis is a serious condition strongly affecting the way a person sees himself and the way he is seen by others. It has tremendous economic and financial ramifications. Psoriasis is linked with social stigmatization, pain, discomfort, physical disability, and psychological distress . Psoriasis is considered an autoimmune disorder mediated by T cells which, after priming by bacterial antigens, migrate to the skin where they are activated by self-antigens expressed by the epithelia and the key participation of dendritic cells that appear also increased in the skin . Vitamin D is a fat-soluble vitamin that is obtained from food supplements and sun exposure. Vitamin D3 is produced from 7-dehydrocholesterol and irradiation of 7-dehydrocholesterol that produces pre-D3, lumisterol, and tachysterol . Ultraviolet (UV) irradiation further converts pre-D3 to lumisterol and tachysterol; at 37°C pre-D3 is converted to D3 . Keratinocytes are the only cells in the body containing the previous pathway. Vitamin D is biologically inert and must undergo two hydroxylation processes in the body to be activated. Keratinocytes are not only capable of producing D3, but of metabolizing D3 via the vitamin D-25 hydroxylase (CYP27A) to 25-hydroxycholecalciferol in the liver and 25OHD-1α-hydroxylase (CYP27B1) to its active metabolite 1,25(OH)2D3 in the kidney . The main function of vitamin D is to keep normal calcium and phosphorus levels in the body to enable normal mineralization of the bone and maintains strong teeth and nail. Vitamin D protects against rickets in children and osteomalacia in adults. Together with calcium, vitamin D also helps to protect older adults from osteoporosis . Vitamin D was primarily acknowledged for its importance in bone formation; however, increasing evidence point to its interference with the proper function of nearly every tissue in our bodies including the brain, heart, muscles, immune system, and the skin. Thereby its deficiency has been incriminated in a long panel of diseases including cancers, autoimmune diseases, cardiovascular, and neurological disorders. Its involvement in the pathogenesis of different dermatological diseases is no exception and has been the subject of much research over the recent years . At least 60 cell types are known to express the vitamin D receptor and more than 200 genes appear to be modulated by vitamin D . The aim of this study is to investigate serum levels of vitamin D in patients with psoriasis compared with healthy controls, and to consider their relation to disease severity.
| Patients and Methods|| |
Study population and selection of patients
This case–control study was conducted at the Dermatology, Andrology and STDs and Medical Biochemistry Departments of Faculty of Medicine, Menoufia University during the period from March 2017 to March 2018; and informed consent was obtained from every patient and control. It included 30 patients with chronic plaque psoriasis and 10 age-matched and sex-matched healthy controls. The patients of this study were divided into four groups: group I (included 10 age-matched and sex-matched healthy controls); group II [included 10 chronic plaque psoriasis patients with mild activity with psoriasis area and severity index (PASI) score <10]; group III included 10 chronic plaque psoriasis patients with moderate activity with PASI score 10–20; and group IV included 10 chronic plaque psoriasis patients with severe activity with PASI score >20. Exclusion criteria included patients on topical or systemic therapy for psoriasis during the last 3 months prior to the study and other skin conditions precluding proper assessment of psoriasis severity. The patients were subjected to the following: (a) full history including personal, family, and clinical history of psoriasis (onset, course, duration, and presence of itching). (b) Clinical examination: general and dermatological examination which include distribution of lesion, presence of nail affection, scalp affection, joint affection, and severity of psoriatic lesions which is assessed according to the PASI score. (c) Laboratory investigations: Collection of blood samples such as the peripheral venous blood samples (5 ml) were withdrawn from every patient under complete aseptic condition into plain tube. After clot formation, centrifugation of samples at 2000g for 10 min was done and serum was separated and stored at −20°C until analysis of vitamin D. Determination of serum 25 hydroxy vitamin D: serum 25 hydroxy vitamin D was measured by enzyme-linked immunosorbent assay (ELISA) using human 25 hydroxy vitamin D ELISA kit. This ELISA kit uses competitive ELISA as the method. The microtiter plate provided in this kit has been precoated with 25 hydroxy vitamin D. During the reaction, 25 hydroxy vitamin D in the sample or standard competes with a fixed amount of 25 hydroxy vitamin D on the solid-phase supporter for sites on the biotinylated detection antibody specific to 25 hydroxy vitamin D. Excess conjugate and unbound sample or standard are washed from the plate, and HRP–streptavidin (SABC) is added to each microplate well and incubated. Then a TMB substrate solution is added to each well. The enzyme–substrate reaction is terminated by the addition of sulfuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm. The concentration of 25 hydroxy vitamin D in the samples is then determined by comparing the optical density of the samples to the standard curve.
The data collected were tabulated and analyzed by SPSS, version 17.0, on IBM compatible computer (IBM Corp., Armonk, New York, USA). Qualitative data were described using number and percent. The Kolmogorov–Smirnov test was used to verify the normality of distribution. Quantitative data were described using range (minimum and maximum), mean, SD, and median. Significance of the obtained results was judged at the 5% level. The tests used were χ2 test, Monte Carlo correction, F test (analysis of variance), Kruskal–Wallis test, and receiver operating characteristic curve. The protocol was approved by the ethical committee of the Menoufia medical school and an informed written consent was obtained from the participants.
| Results|| |
There was nonsignificant difference between the studied groups regarding age and sex [Table 1]. There is significant decrease in the level of serum vitamin D in moderate and severe patient groups compared with the control group whereas nonsignificant difference existed with group II [Figure 1]. There is significant decrease in the level of serum vitamin D in severe cases than in each of mild and moderate cases. Also, there was no nonsignificant difference existed between mild and moderate cases [Table 2]. There is significant negative correlation between serum vitamin D and each of age, disease duration, and PASI score, whereas nonsignificant positive correlation existed with the age of onset of disease [Table 3]. Regarding sensitivity and specificity for vitamin D to diagnosis patients versus control: at a cutoff value of less than or equal to 39.23 ng/ml, the sensitivity was 93.33, specificity 80.0%, positive predictive value (PPV) 93.3%, and negative predictive value (NPV) was 80.0% [Table 4].
|Table 1: Statistical comparison between the different studied groups regarding demographic data|
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|Figure 1: Comparison between the different studied groups regarding vitamin D level.|
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|Table 2: Comparison between the different studied groups regarding vitamin D level|
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|Table 3: Correlation coefficient between serum vitamin D level and different parameters in total patients (n=30)|
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|Table 4: Agreement (sensitivity, specificity) for vitamin D level to diagnosis cases versus control|
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| Discussion|| |
Psoriasis is a hyperproliferative disorder of the skin, and vitamin D3 analogs are widely used in its treatment . Among special properties of 1,25(OH)2D3 are both a prodifferentiating and an ant-iproliferative influence on normal and cancer cells, as well as some immunomodulatory effects . The aim of this study is to investigate serum levels of vitamin D in patients with psoriasis compared with healthy controls, and to consider their relation to disease severity. For this purpose, 30 patients with chronic plaque psoriasis and 10 age-matched and sex-matched healthy controls were included in this study. The patients of this study were divided into four groups: group I (included 10 age-matched and sex-matched healthy controls); group II (included 10 chronic plaque psoriasis patients with mild activity with PASI score <10); group III (included 10 chronic plaque psoriasis patients with moderate activity with a PASI score of 10–20, and group IV included 10 chronic plaque psoriasis patients with severe activity with PASI score >20.
One of the limitations of our study was the number of patients to control was 3:1 not 1:1 as many healthy controls refuse to take blood samples from them as it was painful.
In the current study, there was no significant difference between patients and controls regarding age and sex. This went with Orgaz-Molina et al. .
In the current study, there was no significant statistical difference between patients and controls regarding family history and sun exposure. This went with Maleki et al. . Allayali et al.  who showed that 14% of all participants of the study had a positive family history of psoriasis, while only 11 (16.2%) psoriatic patients had a positive family history of psoriasis with no significant difference between cases and control. Feldmeyer et al.  observed that phototherapy with UVBnb and UVA/UVBnb increased the 25-hydroxycholecalciferol serum level significantly, whereas UVA1 therapy alone induced a reduction in serum 25-hydroxycholecalciferol concentration. However, a considerable source of vitamin D that enables the limitation of sun exposure seems to be its additional food intake in the form of certain foods or dietary supplements. Most meals contain only a little vitamin D3 and those rich in vitamin D3 are eaten irregularly .
In the current study, there was significant decrease in the level of serum vitamin D in moderate and severe patient groups compared with the control group whereas nonsignificant difference existed between mild cases and control. There is also significant decrease in the level of serum vitamin D in severe cases compared with moderate cases, whereas nonsignificant difference existed between mild and moderate patient groups. This agrees with Abdalla and Abdrabo . The results of Filoni et al.  confirmed the reduced vitamin D level in psoriatic patients when compared with healthy controls. These provide new evidence regarding the association of vitamin D level and psoriasis. It was reported that deficiency of vitamin D has been implicated as an environmental trigger for immune-mediated disorders including psoriasis and PA . It was documented that vitamin D status has been associated with an increased risk for Th1 cytokine-mediated autoimmune diseases including insulin-dependent diabetes mellitus (IDDM), multiple sclerosis (MS), inflammatory bowel disease, and rheumatoid arthritis (RA) . The present study detected lower levels of circulating vitamin D in patients with severe psoriasis than in mild and moderate cases. This finding can be explained by the liposolubility of vitamin D and its reduced bioavailability in bodies with a high fat content. Obesity is associated with basic systemic inflammation, characterized by an increase in proinflammatory markers such as TNF-α and IL-6 .
The current study showed that there was significant negative correlation between serum vitamin D levels and each of age, duration of disease, and PASI score. Nonsignificant positive correlation existed with age of onset. This agrees with the results of Bergler-Czop and Brzezińska-Wcisło .
In the current study cause–effect relationship could not be determined whereas Schwalfenberg  reported that low levels of vitamin D may have important implication in the pathogenesis of psoriasis. Vitamin D regulates keratinocyte growth and differentiation. Topical vitamin D derivatives are extensively used as monotherapy or in combination with steroids for the topical treatment of psoriasis. The current study showed that vitamin D was an independent factor of psoriasis to differentiate between patients and controls. At a cutoff value of less than or equal to 39.23 ng/ml, the sensitivity was 93.33, specificity 80.0%, PPV 93.3%, and NPV was 80.0%. The current study found that PASI score and vitamin D serum level were independent factors to predict cases from controls, mild cases from moderate and severe cases, and severe cases from mild and moderate cases. PASI score has higher sensitivity, specificity, PPV, and NPV.
It was found that treatment with vitamin D (35.000 IU daily) resulted in a significant increase in serum level of 25-hydroxycholicalciferol, which correlated with a significant improvement in the PASI score of all patients . It was documented that patients with psoriasis may have lower vitamin D level than the ordinary population due to a series of factors. Low 25(OH)D level can either represent the cause or consequence of psoriasis, resulting from lack of sun exposure from frequent use of drugs that interfere with 25(OH)D metabolism such as gluco-corticoids and immunosuppressive agents or from low 25(OH)D intake .
Many studies have shown the association between serum level of vitamin D and psoriasis . Other studies have shown no association between serum level of vitamin D and psoriasis .
| Conclusion|| |
From this study we can conclude that: decreased 25 OH vitamin D serum level was found in psoriatic patients. The 25 OH vitamin D serum level may be used as a marker of psoriasis severity and response to treatment. But PASI has higher sensitivity, specificity, PPV, and NPV for differentiation of psoriatic patients from controls, mild cases from moderate and severe cases, and severe cases from mild and moderate cases.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]