Implication of Serum Zinc level . with duration and clinical type of Vitiligo

Background: Vitiligo is a common dermatological disorder characlerized by acquired, idiopathic, progressive, hypomelanobis of the skin and hair, with total absence of melanocytes microscopically. Objective: The study was conducted to find out the relationship between serum zinc level and clinical spectrum of vitiligo. Methods: A cross sectional study conducted in the department of Dermatology and Venereology and department of Biochemistry, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh and the period of study was from May 2010 to October 2011. Results: The mean difference of serum zinc level in male and female of both groups were significant (p<0.05) but the mean serum zinc level was not significantly different (P0.05) among various clinical types of vitiligo. In case of localized vitiligo mean serum zinc level was 755.3 + 288.6, in case of acrofacial vitiligo mean serum zinc level was 821.4 +259.6 and in case of generalized vitiligo mean semm zinc level was 771.6 + 222.2. The difference of mean serum zinc level observed between family history positive and negative group were not statistically significant (p>0.05). The difference of mean serum zinc level was also not statistically significant (p>0.05) among <1 year, 1-10 years and 1 1-20 years duration groups of vitiligo patients. A negative correlation (r : 0.227) was observed between duration of symptom with serum zinc level in this study. Conclusion: This study showed low level of serum ztnc rnvitiligo patients. Large-scale studies are needed to confirm these findings and multicenter study should be carried out to reveal the accurate pattern of z;nc status in vitiligo.


Introduction:
Vitiligo is an acquired, often disfigurirg, pigmentary anomaly of the skin manifested by depigmented white patches sulrounded by a noffnal or a hyperpigmented border.lVitiligo usually begins in childhood or adulthood with about half of the cases begin before age 20.The prevalence of the disease ranges from 0.5% to lyo.2,3 The aetiology of the disease is still unknown.Traditionally, there have been three hypothesis to explain vitiligo: neural, immune and self-destruct hypothesis.o Despite the fTct that the aetiology and pathogenesis of vitiligo is not completely known yet, many factors may be responsible for the' disease.Many possible causes, including stress, Address for Correspondence: Dr. Sohail Mkza, Student of MD (Dermatology)   BSMMU, Dhaka.
zinc catalyze the reaffangement of dopachrome to form 5, 6-dihydroxy indole-2 carboxylic acid (DICA) in the process of melanogenesis.e There are differe nt treatment options but none is appropriate for every patient with vitiligo.So, investigations are attempted worldwide for more suitable solutions.In some studies variable degree of correlation between serum zinc level and vitiligo were observed.Serum zinc level was found signific arfiIy low in vitiligo patients than norrnal populations in some sfudies .10'rt't2These previous studies recommended for further studies to be carried out revealing pattern of zrnc status in vitiligo.Variable informations from above sfudies have provided a rationale to conduct the current study.The present sfudy was conducted to measure the serum ztrrc level across clinical spectrum of vitiligo and to compare it with age and sex-matched controls.The sfudy result will provide benefit to the society by providing information regarding vitiligo patients in our country.

Methods:
A cross sectional study conducted in the department Dermatology and Venereology; in collaboration with department of Biochemistry Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh.The period of study was from May 2010 to October 20ll and putposive type of non probability sampling technique was followed in this study.Adatacollection sheet was used for submission of data.Sixty patients with vitiligo attending out-patient department of Dermatology and Vereneology as case and 50 age and sex matched individual without vitiligo as control were enrolled .Cases were grouped into Group A and controls were grouped into Group B. Inclusion criteria's for cases were patients of any age and both sexes, patients not on any treatment with zinc or drugs affecting zlrrc level in the four weeks prior to diagnosis and patient who gave informed consent to be included in the study.Inclusion criterias for control were age and sex matched individual without vitiligo and without the family history of vitiligo, individuals who were willing to give consent to be included in the study and patients not on any form of zinc medication or drugs affectin g zlnc level.Exclusion criterias were patient with leukodenna secondary to other causes and other skin 100 diseases (eg; exfoliative dermatitis,extensive skin burn), patient on any treatment with Zinc or drugs affecting zinc level, patient with other systemic diseases such as liver disease, neoplastic condition, intestinal disease, psycho- logical disease and renal disease, patients having history of alcohol intake, pregnancy and patients with gastrointes- tinal surgery intercurrent illness or other stressful condi- tions or on prolong parenteral nutrition.
A11 patients were explained about the potential risks and obtainable benefits of the study and they were included in the trtal after taking their informed consent.The researcher explained them that they have the right to refuse or accept to participate in the study.A11 patients were ensured that all data obtained during study period from them will be remained confidential.Controls were also included in the trral after taking their informed consent.
This cross sectional study was conducted in the depart- ment of Dermatology and venereology, BSMMU, Dhaka.
Total sixty vitiligo patients were taken as case and 50 age and sex matched individuals without vitiligo from a selected community were taken as control.They were approached for the study.The aims and objectives of the sfudy along with its procedure, risks and benefits were explained to the patients in easily understandable local language and then informed written consent were taken from the interested patients and controls.Socio- demographic datawere taken from the patients or reliable informants.Vitiligo patients were selected clinically from patients with whitish depigmented patches excluding patients with leukodenna second ary to other causes such as pityriasis aba, sarcoidosis, sclerodeffna, pityriasis versicolor, post inflammatory hypomelanosis etc.The diagnosis was confirmed by Wood's lamp examination for sfudy purpose and all other selection criteria's also were fulfilled for each case and control.Then 5 ml of venous blood was collected in special a sterile tube from both cases and control and was centrifuged for 15  After collection, data were checked for inadequdcy, irrelev ancy, and incons i stency.Irrelevant and inc ons i stent data were discarded.Analysis of data was performed by chi square test and unpaired t test and ANOVA TEST by using SPSS (The  The main objective of the study was to find out the relationship between serum zinc level with vitiligo.Mean age of the group A patients was 29.9 years with a standard deviation of +13.9 years and in group B 31.5 years with a standard deviation of t9.0 years.The mean difference was not significant (prO.05) between these two groups.Male was found 27 (45.0%) in group A and 28(56.0%) in group B. Female was found 33(55 .0%)and 22(44.0%) in group A and group B respectively.The difference was not statis- tically significant (p>0.05) between these two groups.The mean serum ztfic levels observed in male were 768.5*233.8ppb and 939.3+218.7 ppb in group A and group B respectively.In female the mean serum zinc level were 71,9.1*258.9ppb in group A and 975+334.1 ppb in group B. The mean difference of serum zinc level in male and fernale of both groups were significant (p<0.05).
There was no significant difference of mean serum zinc level between male and female in each group (Table I).
Serum zinc level was signific arrtly lower in group-A (case) than that of group-B (control).But, serum zinc level was noffinal and higher respectively in group B (control) than that of group-A (case) which were statisti- cally significant (Table  II).
The mean serum zinc level was not signific antly different (p>0.05)among various clinical types of vitiligo.In case of localized vitiligo mean serum zinc level was 755.3 + 288 .6, in case of acrofacialvitilig, mean serum zinc level was 821.4 + 259.6 and in case of generalized vitiligo mean serum zinc level was 77I.6 *222.2.(Tab1e III).The difference of mean serum zinc level observed between family history positive group and in family history negative group was not statistically significant (p>0.05) between these two groups.The mean serum zinc level of family history positive group was 756.9+242.7 and the mean serum zinc level of family history negative group was 662(Table IV).The difference of mean serum zinc level was not statistically significant (p>0.05)among <1 yaffi, 1-10 years and Il-20 years duration groups of vitiligo patients.The mean serum zinc level among the duration (1 year was 734.6 + 243.6, the mean serum zinc level among the duration 1-10 years was 723.6 + 238 and the mean serum zinc level among the duration lI-20 years was 780.0 + 288.9. (Table V).A negative correlation (r --0.227) was observed between duration of symptom with serum zinc level in this study (Figure 1).  the current sfudy where male female ratio was almost 0.8:1 in vitiligo patients.This may be due to the religious and social patterns of our country for which women may less frequently get chances to come to the physicians.Our study findings was similar with Shameer et aI.regarding clinical type of vitiligo observed in their study.Shameer et al. reported that vitiligo vulgaris (85.0%) was the cofitmonest morphological pattern followed by mucosa vitiligo Q\.a%), segmental vitiligo (3.3%) and acrofacial vitiligo (1.6%).10 In the present study, most of vitiligo patients had a positive family history similar with Shameer et al.

Conclusion:
This study has shown an important association between zinc level and vitiligo .Large-scale studies are needed to confirm these findings and multicenter study should be carried out to reveal the aceurate pattern of zinc stafus in vitiligo.
minutes at 2000 rpm (Rotations per minute).The supernatant serum was transferred to a separate sterile tube (Appendor| and kept at-35oc in the deep freezer till the analysis.The serum zinc levels were measured by Atomic absorption spectrophotometer (AAS) fGrapphyte Method] at l Zinclevel with duration and clinical Biochemistry Dept. of BSMMU.Then serum zinc"level of the vitiligo patients were compared with both age and sex matched controls and internationally accepted normal serum zinc level (700-1200 ppb).
Statistical Package for the Social Science for the Windows 16.0) software.Statistical significance has been set at 5% level and confidence interval at 95o/o level.This case control study conducted in the department of Dermatology and Venereology of Bangabanddhu Sheikh Mujib Medical University, Dhaka.Cases were grouped into Group A and controls were grouped into Group B.

Table - I
Distribution of the study of the subjects by age and sex Range (min-max) (350-1200) (100-1700) s-Significant; ns-not significant 97 5+334.tSerum zinc level (ppb) table-II Distribution of the subjects by serum zinc level (n-il0)

Table - V
Mean Zinc level according to duration of vitiligo.In this study the mean age was almost similar in both groups.Shameer et al. shown the mean age 33.8 years in vitiligo patients and 29.2 years in control, which is consistent with the current study.lOShameer et al. found male female ratio was 4.5:1. 10Male female ratio observed by Arora et al. was 2:1. 11These do not coffespond with 10They

Table - IV
11an serum zinc level according to family history in Implication of Serum Zinc level with duration and clinical Wpe of Vitilieo.Sohail Mirza et al They found 33.0% of the patients with positive .familyhistory.However, Shameer et aL.found low levels of serum zinc in the majoriff of the patients with duration of disease ranging from 2 to 5 years, which coffesponds with the current sfudy.10Themeanduration of disease was 5.4*0.66 years in this study.Shameer et al. found the mean duration of the disease was 2 years, which is a little lesser than the present study.'0Thismaybeduetopatients of our country usually come to health service centre in late stage of their disease.A case control sfudy by Shameer et al. showed low zinc level in 1 3(21.6%)out of the 60 patients.Only one patient showed an elevated level of zinc for the age and sex.The serum zinc levels in the control group were within the normal range.loThiscorrespondswiththecurrentsfudy.In this study serum zinc level was signific antly lower in group-Athan group-B.Serum zinc levels were studied by Arora et al in 7 5 patients of different cutaneous disorders and 24 healthy controls."Nosignificantcorrelationwasfoundinothercutaneousdisorders studied.Molokhia & Portnoy found mean serum zinc level 9.1 pCg and L0.4 pglgin vitiligo patients and control respec- tively.11Statisticallymeanserumzinclevel of vitiligo patients was significantly lower than that of control.This also coffesponds with the current study.Simllar observations of si$nificantly low serum zinc level in patients with vitiligo were made by Bruske & Salfeld ."Anegativecorrelationwasobserved between duration of symptom with serum zinc level in this study which was not statistically significant.It indicates that serum zinc declines with increased duration of symptoms.Aroraet al. found no significant alteration in serum zinc level in vitiligo.This possibly supports the autoimmune theory of vitiligo.t3Conversely,Helmyet al. showed that serum zinc and copper levels were significantly higher in active vitiligo patients compared to controls.While serum zinc and copper levels insignificantly higher in active vitiligo versus stable disease and in stable patients versus controls.It appears that increased apoptosis of peripheral blood mononuclear cells in active vitiligo will lead to release of zinc and copper in serum (as zinc is present maximally intracellular), resulting in increasing their serum levels significarfiLy in active vitiligo.toInamadaretal.reported appearance of vitiligo-like depigmented cutaneous lesions in two siblings with acrodermatitis entropathica who developed decreased serum zinc level due to discontinuation of zinc supplements.15