Clinical and Epidemiological Characteristics of Vitiligo at Different Ages: An Analysis of 571 Patients in Northwest China

Jing-Zhan Zhang, Dong Luo, Cai-Xia An, Chen Xu, Ya-Nan Zhao, Jin-Xi Li,Shi-Rong Yu, De-Zhi Zhang, Xiao-Jing Kang?

Department of Dermatology, People’s Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China.

Abstract Objective:This study was performed to elucidate the clinical and epidemiological characteristics of vitiligo patients of different ages in Northwest China.Methods:We retrospectively reviewed the case records and questionnaires of all patients diagnosed with vitiligo,who visited People’s Hospital of Xinjiang Uygur Autonomous Region from May 2016 to December 2017.The clinical and epidemiological characteristics of these patients were analyzed by Pearson’s x2 test and Fisher’s exact test.Results:In total,we collected data of 571 vitiligo patients with age of 32.9±16.4 years.The prevalence of segmental vitiligo in children and adolescents ≤19 years old(24/175[13.7%])was higher than that in adults aged from 20-59 years(23/370[6.2%])and advanced patients aged ≥60 years(1/26[3.8%])(P=0.020).The prevalence of progressive vitiligo was higher in children and adolescents ≤19 years(72/175[41.1%])and adults from 20-59 years(141/370[38.1%)than in patients ≥60 years(5/26[19.2%])(P=0.063).Children and adolescents ≤19 years with vitiligo had a higher rate of a family history of vitiligo (20/175[11.4%]) than adults (20/370[5.4%]) and advanced age (1/26[3.8%]) (P=0.031).Conclusions:This study provides clinical evidence that vitiligo at different ages has different characteristics,mainly regarding an increased incidence of segmental vitiligo,a higher prevalence of atopic dermatitis and halo nevus,and a more common positive family history among children and adolescent patients.

Keywords: vitiligo, age grouping, epidemiology, prevalence

Introduction

Vitiligo is a common acquired pigmented skin disease,not only places economic pressure on patients, but also seriously affects patients’ mental health and social activities.1-2Many studies have focused on the clinical features of vitiligo.3-6However, the clinical and epidemiological characteristics of vitiligo at different ages are limitedly studied especially in Northwest China.

In the present study, we analyzed the general situation,clinical manifestations, and associated diseases of 571 patients with vitiligo, to further study the clinical and epidemiological characteristics of vitiligo in different age groups and provide a possible basis for early treatment of vitiligo.

Materials and methods

Study population

Electronic and paper medical records were collected to identify patients diagnosed with vitiligo in the Department of Dermatology of the People’s Hospital of Xinjiang Uygur Autonomous Region from May 2016 to December 2017.Vitiligo was diagnosed according to family history,clinical manifestations,and Wood lamp or pathological examination of the skin by experienced dermatologists. Vitiligo was broadly classified into segmental, nonsegmental,mixed, and unclassified disease according to the 2013 European guidelines for the management of vitiligo.7Unclassified vitiligo was diagnosed after a sufficient observation time(and,if necessary,further investigations,for example, history of trauma).

The patients were divided into three age groups:children and adolescents(≤19 years old),adults(20-59 years old),and advanced age (≥60 years old).

Data collection

Vitiligo questionnaires of unified formulation were conducted by trained investigators in the outpatient clinic or wards. The clinical and epidemiological profiles of the patients were based on careful analysis of the following variables: sex, age, race, educational status, occupational status, underlying associated diseases, precipitating factors, clinical type, site/distribution of vitiligo lesions,disease activity, duration of the disease, smoking status,drinking status, and family history of vitiligo.

The age at onset was defined as the age at which the patient first discovered the disease and was diagnosed as vitiligo by a physician.The patients’age was calculated in 1-year increments. Mental factors were defined as being present for at least 3 days a week prior to onset with the presence of tension, anxiety, depression, stress, and sadness for ＞3 hours per day. Sun exposure for ≥3 days per week for 1 month prior to onset and ≥3 hours per day was defined as positive. Overwork was defined as work performed for ≥3 days a week within 1 month prior to onset and ＞10 hours per day.Physical trauma was defined as positive in the presence of bruises,burns,cuts,surgery,corrosion, or similar lesions on the skin before the occurrence of lesions. A family history of vitiligo was defined as the presence of disease in first-or second-degree relatives. The study protocol was approved by the ethics committee of the hospital and all participants signed the informed consent.

Statistical analysis

Descriptive statistics were used to summarize the demographics and clinical characteristics of the patients.Pearson’s x2test and Fisher’s exact test were used to compare the distribution of qualitative variables.APvalue of ＜0.05 was considered statistically significant.

Results

In total, 571 patients with vitiligo were included in this study. The sociodemographic characteristics of the study subjects are shown in Table 1. Race, educational status,and occupational status were also examined.

Table 2 shows the clinical profiles of all patients with vitiligo. Significant differences were found among age groups. Nonsegmental vitiligo was the main type among all age groups.The proportion of segmental vitiligo in the children and adolescents groups (24/175[13.7%]) was higher than that in the adults (23/370[6.2%]) and the advanced age group (1/26[3.8%]) (P=0.020). With respect to disease duration, most respondents indicated that they had a vitiligo course from 1 to 10 years,and theproportion was (116/175[66.3%]) of children and adolescents, (238/370[64.3%]) of adults, and (14/26[53.8%]) of advanced age, respectively (P＜0.001).

Table 1 Sociodemographic characteristics of 571 patients with vitiligo (n, %)

Psychological stress was associated with the occurrence of disease in (118/370[31.9%]) of patients in the adult group, (34/175[19.4%]) of the children and adolescents,and (3/26[11.5%]) of the patients of advanced age,respectively (P=0.002). The number of cases of vitiligo induced by sunlight was higher in the adults than that in the children and adolescents and in the patients of advanced age (P=0.022). The incidence of trauma in children and adolescents, adults, and advanced age was(28/175[16.0%]), (34/370[9.2%]), and(2/26[7.7%]), respectively (P=0.053). Significant differences were also found in the diseases associated with vitiligo among different age groups (Table 2). Children and adolescents with vitiligo had a higher positive rate of a family history of vitiligo (20/175[11.4%]) than did adults (20/370[5.4%])and patients of advanced age (1/26[3.8%]) (P=0.031).

Table 2 Clinical characteristics of 571 patients with vitiligo (n, %)

Discussion

In this study, the incidence rate of vitiligo was higher among female than male patients. This is similar to the study results reported by Konget al.3and Matz and Tur,8while other studies showed no difference between male and female patients.This difference in the sex ratio may be caused by resource of subjects.

Children and adolescents have a higher prevalence of segmental vitiligo. This finding is consistent with that reported by de Barroset al.4Most cases of vitiligo are sporadic, and the face and neck are the most commonly affected parts. This may be because these regions are directly exposed to ultraviolet rays, which result in the depletion and premature aging of the local melanocytes with a high density.9

Negative life events may stimulate or induce the onset of vitiligo. Because children are active with poor safety awareness, they are more likely to sustain trauma. That may explain that the children have a higher risk of traumatic factors associated with vitiligo than the adults and advanced age. Most adolescents and adults are experiencing academic stress or a career start-up and emotional life. The probability of exhaustion, tension,stress, and other such emotions is generally higher in this age group, which also promotes the onset of vitiligo to a certain extent.

Vitiligo has been found to be associated with autoimmune and non-autoimmune disorders. Clinicians should have a certain understanding of the common complications of vitiligo and screen patients for relevant diseases in order to obtain better therapeutic effects.Previous studies have shown that the incidence of atopic dermatitis in earlyonset vitiligo is higher than that in late-onset vitiligo.5,10A common pathway such as that involving thymic stromal lymphopoietin may explain these correlations.A common cell-mediated immune pathogenesis of vitiligo and psoriasis,such as the Th17 pathway,may contribute to a similar pattern of hyperactive cellular responses in the both diseases.11

According to previous reports,the incidence of vitiligo in patients with alopecia is 3%to 8%.12-13Increased levels of reactive oxygen species and high cellular stress have been proposed as triggers for the innate immune response in both diseases.The specific mechanism is still unclear.The incidence of adult alopecia areata in this study is low and remains to be confirmed by further large sample studies.Some studies have shown that vitiligo in patients with autoimmune thyroid disease is mainly non-segmental,and in the segmental type is rare.14-15In this study, the incidence of non-segmental vitiligo was high in the adults(322/370[87.0%])and advanced age(25/26[96.2%])with a high incidence of thyroid dysfunction. Similar to our results,hypertension and diabetes mellitus have also been reported as underlying associated diseases among patients with vitiligo in a previous study.6

This familial aggregation indicates the role of genetic mechanisms in the pathogenesis of vitiligo.Genome-wide linkage analyses have identified multiple linked genes associated with vitiligo.16-17In the present study, the children and adolescents had a higher positive rate of a family history of vitiligo than that of adults and advanced age. However, some scholars have found that a family history had no correlation with the location,distribution,or course of the disease.18So,the genetic factors are only considered as the background mechanism of vitiligo, not the dominant mechanism. Autoimmune and oxidative stress may play an indispensable role in the pathogenesis of vitiligo, similar to a trigger switch. However, the number of patients in this study was small,which may have been a bias in the results.

In conclusion,this study has shown that the clinical and epidemiological profiles differ among vitiligo patients of various ages. Compared to the adults and advanced age groups, the children and adolescents have an increased incidence of segmental vitiligo, associated with a higher prevalence of atopic dermatitis and halo nevus, and a family history.The most precipitating factors of the adult patients with vitiligo are mental factors and overwork.The advanced age vitiligo patients have a longer duration of disease compared to other ages.