Key PointsQuestion
What are the global prevalence and incidence of oral lichen planus?
Findings
In this systematic review and meta-analysis of 46 studies, 15 included general population data (n = 462 993), and 31 included information from clinical patients (n = 191 963). The overall estimated pooled prevalence of oral lichen planus was 0.89% among the general population and 0.98% among clinical patients.
Meaning
This study identified the global prevalence and incidence of oral lichen planus in terms of its spatial, temporal, and population distribution.
Importance
Integrated information on the global prevalence and incidence of oral lichen planus (OLP) is lacking.
Objective
To examine the global prevalence and incidence of OLP in a systematic review and meta-analysis.
Data Sources
A systematic review of population-based studies and clinic-based studies reporting the prevalence and incidence of OLP was performed using 3 electronic medical databases (Cochrane Database of Systematic Reviews, Embase, and MEDLINE) from their inception to March 2019. The search terms included “(lichen planus or LP) and (prevalence or incidence or epidemiology).” No language restriction was applied.
Study Selection
Observational descriptive studies investigating the prevalence and incidence of OLP were included.
Data Extraction and Synthesis
Data were extracted by continent, sex, and other characteristics. The risk of bias was assessed by the Joanna Briggs Institute Critical Appraisal Instrument for Studies Reporting Prevalence Data using random-effects models to synthesize available evidence.
Main Outcomes and Measures
The primary outcome was the prevalence (with 95% CIs) of OLP among the overall population and among subgroups. Between-study heterogeneity was assessed using the I2 statistic.
Results
Among 46 studies, the overall pooled estimated prevalence of OLP was 0.89% (95% CI, 0.38%-2.05%) among the general population (n = 462 993) and 0.98% (95% CI, 0.67%-1.43%) among clinical patients (n = 191 963). Among the 15 population-based studies, the prevalence of OLP was 0.57% (95% CI, 0.15%-2.18%) in Asia, 1.68% (95% CI, 1.09%-2.58%) in Europe, and 1.39% (95% CI, 0.58%-3.28%) in South America. Among the 31 clinic-based studies, the prevalence was 1.43% (95% CI, 1.12%-1.83%) in Africa, 0.87% (95% CI, 0.61%-1.25%) in Asia, 1.03% (95% CI, 0.51%-2.09%) in Europe, 0.11% (95% CI, 0.07%-0.16%) in North America, and 3.18% (95% CI, 0.97%-9.95%) in South America. The pooled prevalence of OLP by sex was 1.55% (95% CI, 0.83%-2.89%) for women and 1.11% (95% CI, 0.57%-2.14%) for men in the population-based studies and 1.69% (95% CI, 1.05%-2.70%) for women and 1.09% (95% CI, 0.67%-1.77%) for men in the clinic-based studies. In 5 clinic-based studies providing the age distribution of patients with OLP, the prevalence by age was 0.62% (95% CI, 0.33%-1.13%) among patients younger than 40 years and 1.90% (95% CI, 1.16%-3.10%) among patients 40 years and older.
Conclusions and Relevance
This study identified the global prevalence and incidence of OLP in terms of its spatial, temporal, and population distribution. The overall estimated pooled prevalence of OLP was 0.89% among the general population and 0.98% among clinical patients. A higher prevalence of OLP was found in non-Asian countries, among women, and among people 40 years and older. The findings should be considered with caution because of the high heterogeneity of the included studies.
Quiz Ref IDOral lichen planus (OLP) is a T-cell–mediated and chronic inflammatory disorder affecting the oral mucosa,1 with an incidence that is higher in women than in men. The affected age range varies around the world,2 and the disease is rare in children.3 Smokers and patients who abuse alcohol have a higher prevalence of OLP.4
Oral lichen planus can be caused or triggered by a genetic malfunction or by environmental factors. Although the cause remains unknown, the immunological system plays a substantial role, and several factors are well known, such as psychological stress, drug intake, and anxiety.5-7 Oral lichen planus may be associated with some systemic diseases, including hepatitis C virus infection, hypertension, diabetes, graft-vs-host disease, and thyroid dysfunction.8-11 However, the precise role of most of these conditions in OLP remains unclear.
It is a challenge to diagnose OLP, particularly in the absence of the classic reticular pattern on oral mucosal surfaces.12 Therefore, an oral biopsy with histopathological examination is usually required to confirm the clinical diagnosis and exclude dysplasia and cancer.13 Furthermore, oral lichenoid lesions, such as lichenoid contact lesions, lichenoid drug reactions, and lichenoid lesions of graft-vs-host disease, may confuse the differential diagnosis. In 1978, the World Health Organization published a set of clinicopathological criteria to better define the criteria for diagnosis of OLP.14 However, these criteria lacked consensus regarding clinical and histological diagnosis of OLP. In 2003, modifications were proposed to the World Health Organization criteria,15 which identified an association between oral lichenoid lesions and OLP. Direct immunofluorescence, although not specific for OLP, is a key tool in differentiating some lichenoid lesions, including erythematous lupus, chronic ulcerative stomatitis, and lichen planus pemphigoid, especially when they have overlapping clinicopathological features.1,16 Therefore, combinations of clinical findings, histopathological examination results, and direct immunofluorescence can help achieve an accurate diagnosis.
Integrated information about the global prevalence and incidence of OLP is lacking. Therefore, we performed a systematic review and meta-analysis of the published literature (1) to examine the global prevalence and incidence of OLP both among the general population and among clinical patients and (2) to analyze the association between prevalence and possible related variables (eg, publication year, geographic location, sex and age distribution, and diagnostic methods).
In this systematic review and meta-analysis, a literature search was performed using 3 electronic medical databases (Cochrane Database of Systematic Reviews, Embase, and MEDLINE) from their inception to March 2019. Searches were conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search terms included “(lichen planus or LP) and (prevalence or incidence or epidemiology)” (the search strategy is provided in eAppendix 1 in the Supplement). No language restriction was applied. The final search was conducted on March 10, 2019.
Inclusion and Exclusion Criteria
We predefined the inclusion criteria for eligible studies as follows: (1) original investigations; (2) observational studies with a cross-sectional, case-control, or cohort design; and (3) reports of the point prevalence of OLP or sufficient data to calculate OLP among the general population or among clinical patients. There were no restrictions regarding publication year. If more than 1 study evaluated the same population, only the larger study was included. Studies were excluded if (1) they were review articles, case reports, protocols, short communications, personal opinions, letters, posters, conference abstracts, or laboratory research; (2) they did not report sufficient data, and efforts to contact the authors were unsuccessful; or (3) they did not involve patients with OLP.
The articles were screened for relevance in the title and abstract. The relevant abstracts and any articles without abstracts were selected for full-text review. Two of us (C.L. and X.T.) collected information from the included studies independently and cross-checked the information to ensure the integrity of the contents. Discrepancies were resolved by discussion with a third one of us (X.Z.). We inserted the data into 2 tables, with one listing the population-based studies (Table 1 and eTable 1 in the Supplement) and the other listing the clinic-based studies (Table 2 and eTable 2 in the Supplement). The gathered data included author, publication year, country, continent, sex and age, study period, diagnosis, interviewer, quality appraisal score, sample size, and estimated prevalence.
The risk of bias of the included studies was independently assessed using the Joanna Briggs Institute Critical Appraisal Instrument for Studies Reporting Prevalence Data63 by 2 of us (C.L. and X.T.). Another one of us (S.G.) was involved in the event of ambiguity (eTable 1 in the Supplement). There were 9 items in total: (1) Was the sample frame appropriate to address the target population? (2) Were study participants sampled in an appropriate way? (3) Was the sample size adequate? (4) Were the study participants and the setting described in detail? (5) Was the data analysis conducted with sufficient coverage of the identified sample? (6) Were valid methods used for identification of the condition? (7) Was the condition measured in a standard, reliable way for all of the participants? (8) Was there an appropriate statistical analysis? (9) Was the response rate adequate? If not, was the low response rate managed appropriately? Higher total scores indicated better quality and lower risk of a study. Studies were categorized based on the percentage of yes answers as high quality (≤49%), moderate quality (50%-69%), or low quality (≥70%).
Data analysis was performed using the metaprop module in the R statistical software package, version 3.5.3. We previously adopted the logit method to transform the prevalence reported in each study, followed by an inverse-variance–weighted random-effects meta-analysis using the method by DerSimonian and Laird.64 Next, we obtained the pooled prevalence (with 95% CIs) of OLP among the overall population and among subgroups. Between-study heterogeneity was assessed using the I2 statistic and the P value for heterogeneity (Cochrane Q statistic), which describe the percentage of variation across studies that is due to heterogeneity rather than pure chance. Forest plots were used to show the results graphically. Publication bias was assessed using the Egger test and was shown using funnel plots. The amount of true heterogeneity (the variance or the SD) was indicated by τ2. We also considered 2 different estimators of residual heterogeneity (I2 and τ2) in random-effects meta-regression using metafor in the R package.65 To test whether subgroup associations were credible or not, we developed 2 hypotheses (subgroup by continent and subgroup by diagnostic methods) to explain variability in effect estimates of the primary outcome, which was the prevalence of OLP among the overall population and among subgroups. Subgroup analysis was performed based on continent, sex and age, and diagnostic methods. The following 3 diagnostic methods are described in the present study: C, indicating clinical diagnosis; P, indicating pathological diagnosis; and C(P), indicating that after clinical diagnosis histopathological diagnostic procedures were performed if necessary. Two-sided P < .05 was considered statistically significant.
Literature Search and Included Studies
Using the search term “(lichen planus or LP) and (prevalence or incidence or epidemiology)” resulted in 7804 records from the 3 databases. The PRISMA flow diagram shows the search history (Figure 1). This search resulted in the inclusion of 46 studies17-62 (full citation details of the included studies are provided in eAppendix 2 in the Supplement), 15 of which were population-based studies17-31 (n = 462 993) and 31 of which were clinic-based studies32-62 (n = 191 963), with sample sizes ranging from 304 to 402 669.
The 15 population-based studies17-31 represented 13 different countries (Table 1). Two studies20,23 were conducted in South America, 5 studies24-26,29,30 in Europe, and 8 studies17-19,21,22,27,28,31 in Asia. Among these 15 studies, 2 reported the prevalence of OLP in Cambodia,17,28 and 2 reported the prevalence of OLP in China.19,21
The 31 clinic-based studies32-62 represented 17 different countries (Table 2). Seven studies32,34,43,50,53,55,56 were conducted in Europe, 19 in Asia,33,35,37-40,42,44,45,47-49,51,52,57,58,60-62 3 in South America,41,46,54 1 in Africa,36 and 1 in North America.59 Among these 31 studies, 9 reported the prevalence of OLP in India,35,37,40,42,44,45,49,61,62 3 in Saudi Arabia,47,58,60 2 in Yemen,33,38 2 in Italy,34,50 2 in Brazil,41,46 2 in Turkey,48,51 and 2 in Thailand.52,57
Only 3 studies reported on the incidence of OLP. For a study66 in South India, the incidence was 2.48 (95% CI, 2.12-2.83) per 1000 person-years, with rates of 2.14 (95% CI, 1.65-2.64) per 1000 person-years for men and 2.76 (95% CI, 2.25-3.27) per 1000 person-years for women. Based on a 10-year follow-up period, the highest incidence was in the group aged 55 to 64 years for men and in the group aged 45 to 54 years for women. However, a study67 in Japan reported that the age-adjusted incidence of OLP was 59.7 (95% CI, 7.4-112.1) per 100 000 person-years for men and 188.0 (95% CI, 96.0-280.1) per 100 000 person-years for women, rates that were somewhat lower than those reported from South India. A recent study68 in the United States showed that the incidence of OLP was 11.4 (95% CI, 10.1-12.7) per 100 000 person-years, with rates of 8.1 (95% CI, 6.5-9.6) per 100 000 person-years for men and 14.4 (95% CI, 12.3-16.4) per 100 000 person-years for women.
Overall Prevalence of OLP
Prevalence estimates for OLP derived by meta-analysis are shown in Figure 2 and Figure 3. Estimates for the population-based studies ranged from 0.02% to 3.25% (Figure 2), and the random-effects overall pooled estimated prevalence of OLP was 0.89% (95% CI, 0.38%-2.05%), with very high heterogeneity (I2 = 99%; P < .001). Estimates for the clinic-based studies (most patients visited the stomatology clinic) ranged from 0.08% to 6.04% (Figure 3), and the random-effects pooled overall estimated prevalence of OLP was 0.98% (95% CI, 0.67%-1.43%) (I2 = 99%; P < .001).
Prevalence of OLP by Diagnostic Methods
When the studies were categorized by different diagnostic methods of OLP, similar pooled proportions of OLP were found among different subgroups (eFigure 1 and eFigure 2 in the Supplement). Twelve17-19,21,23-29,31 of the 15 population-based studies17-31 diagnosing OLP were based on clinic visits (n = 439 907), and the combined prevalence estimate of OLP was 0.86% (95% CI, 0.30%-2.47%), with very high heterogeneity (I2 = 99%; P < .01). Only 1 study22 was based on both clinical diagnosis and pathological diagnosis (n = 1167), and the prevalence estimate of OLP was 0.51% (95% CI, 0.23%-1.14%).
Two studies20,30 were based on histopathological diagnostic procedures after clinical diagnosis (n = 21 919). The prevalence estimate of OLP was 1.39% (95% CI, 0.62%-3.09%). The prevalence estimate of OLP was 1.39% (95% CI, 0.62%-3.09%), with very high heterogeneity (I2 = 89%; P < .01).
Among the 31 clinic-based studies,32-62 8 studies32,38,42,47,52,60-62 reported the prevalence of OLP by clinical diagnosis (n = 27 291), with a combined prevalence estimate of OLP of 0.74% (95% CI, 0.43%-1.28%), and the random-effects overall pooled estimated prevalence of OLP was 0.89% (95% CI, 0.38%-2.05%), with very high heterogeneity (I2 = 91%; P < .01). Nine studies34,35,37,39,41,43,44,48,58diagnosed OLP based on both clinical diagnosis and pathological diagnosis (n = 99 201), and the combined prevalence estimate of OLP was 1.23% (95% CI, 0.61%-2.44%), with very high heterogeneity (I2 = 99%; P < .01). The remaining 14 studies33,36,40,45,46,49-51,53-57,59 with histopathological diagnostic procedures after clinical diagnosis (n = 65 471) showed that the prevalence estimate of OLP was 0.97% (95% CI, 0.52%-1.81%), with very high heterogeneity (I2 = 98%; P < .01).
Only 1 study40 diagnosed OLP with combined clinicopathological and direct immunofluorescence methods when there was suspicion of other diseases (n = 3500). The prevalence estimate of OLP was 0.34%.
Prevalence of OLP by Publication Year
To understand whether there was an association between time and the prevalence of OLP, we ran an association analysis on publication year (eFigure 3 in the Supplement). The graph shows that the prevalence of OLP fluctuated with publication year, ranging from 0.02% in 1965 to 3.25% in 2002 among the population-based studies17-31 and ranging from 0.08% in 1991 to 6.04% in 2010 among the clinic-based studies.32-62 According to the scatterplot, no statistically significant association was observed between a higher or lower prevalence of OLP and publication year.
Prevalence of OLP by Continent
Most of the 15 population-based studies17-31 were from Asia (n = 436 615), only 5 were from Europe (n = 23 903),24-26,29,30 and 2 were from South America (n = 2475).20,23 The 31 clinic-based studies32-62 were more widespread across the world, with 19 from Asia (n = 94 854),33,35,37-40,42,44,45,47-49,51,52,57,58,60-62 7 from Europe (n = 32 745),32,34,43,50,53,55,56 3 from South America (n = 36 278),41,46,54 1 from Africa (n = 4470),36 and 1 from North America (n = 23 616).59 Among the 15 population-based studies,17-31 the prevalence of OLP was 0.57% (95% CI, 0.15%-2.18%) in Asia (with very high heterogeneity [I2 = 99%; P < .01]), 1.68% (95% CI, 1.09%-2.58%) in Europe (with very high heterogeneity [I2 = 79%; P < .01]), and 1.39% (95% CI, 0.58%-3.28%) in South America (with very high heterogeneity [I2 = 84%; P = .01]) (eFigure 4 in the Supplement). Among the 31 clinic-based studies,32-62 the prevalence of OLP was 1.43% (95% CI, 1.12%-1.83%) in Africa, 0.87% (95% CI, 0.61%-1.25%) in Asia (with very high heterogeneity [I2 = 94%; P < .01]), 1.03% (95% CI, 0.51%-2.09%) in Europe (with very high heterogeneity [I2 = 99%; P < .01]), 0.11% (95% CI, 0.07%-0.16%) in North America, and 3.18% (95% CI, 0.97%-9.95%) in South America (with very high heterogeneity [I2 = 100%; P < .01]) (eFigure 5 in the Supplement).
A sex difference in the prevalence of OLP was observed between the 15 population-based studies17-31 and the 31 clinic-based studies.32-62 Among the 15 population-based studies,17-31 only 8 studies19-21,23,24,26-28 reported the number of men and women with and without OLP, and 1 study28 included only women. These 9 studies included a total of 16 295 women (57.2%) and 12 188 men (42.8%). The pooled prevalence of OLP was 1.55% (95% CI, 0.83%-2.89%) for women (with very high heterogeneity [I2 = 93%; P < .01]) and 1.11% (95% CI, 0.57%-2.14%) for men (with very high heterogeneity [I2 = 88%; P < .01]) (eFigure 6 in the Supplement). Among the 31 clinic-based studies,32-62 15 studies33,34,36,38,40,42,49,51-55,57,58,62 reported the prevalence of OLP by sex, with 22 055 women (50.6%) and 21 516 men (49.4%). The pooled proportions of OLP were 1.69% (95% CI, 1.05%-2.70%) for women (with very high heterogeneity [I2 = 95%; P < .01]) and 1.09% (95% CI, 0.67%-1.77%) for men (with very high heterogeneity [I2 = 93%; P < .01]) (eFigure 7 in the Supplement). The prevalence of OLP appeared to be lower among men than among women.
Most of the 46 studies included individuals older than 15 years. Two population-based studies23,29 and 1 clinic-based study52 examined geriatric patients 60 to 65 years and older, whereas 4 clinic-based studies37,43,57,61 did not report any data on age. Only 5 clinic-based studies33,44,49,50,53 provided the age distribution of patients with OLP. The results of these 5 studies indicated that the prevalence of OLP was 0.62% (95% CI, 0.33%-1.13%) among patients younger than 40 years (with very high heterogeneity [I2 = 78%; P < .01]) and 1.90% (95% CI, 1.16%-3.10%) among patients 40 years and older (with very high heterogeneity [I2 = 89%; P < .01]) (eFigure 8 in the Supplement).
Among the 15 population-based studies,17-31 Egger test indicated that there was no statistically significant publication bias (P > .05). However, among the 31 clinic-based studies,32-62 Egger test showed statistically significant publication bias (P < .05) (eAppendix 3 in the Supplement). Therefore, publication bias could be a source of heterogeneity.
Metaregression showed that neither continent nor diagnostic methods could be a source of heterogeneity (P > .05) (eTable 2 in the Supplement). Heterogeneity between the included studies was also accounted for (I2 = 0% and τ2 = 0).
To the best of our knowledge, this is the first systematic review and meta-analysis of the global prevalence and incidence estimates of OLP among both the general population and clinical patients. Quiz Ref IDThis analysis showed that the overall estimated prevalence of OLP is 0.89% among the general population and 0.98% among clinical patients. The present study also provided evidence that the prevalence of OLP is higher among women compared with men, predominantly affecting those aged 40 years and older. Moreover, the prevalence of OLP is lower in Asian countries than in non-Asian countries. No publication year–dependent gradient in the prevalence of OLP was observed. Our findings should be considered with caution because of the high heterogeneity of the included studies.
There was high heterogeneity among the studies addressing the prevalence and incidence of OLP for several possible reasons. Because of the insufficient understanding of diagnostic criteria for the clinical diagnosis of OLP resulting from the variety of clinical and pathological features that may be present, it was challenging for the OLP diagnosis to inevitably depend on physician experience, especially when clinical manifestations are atypical. Moreover, it is difficult to distinguish OLP from other oral mucosal disease, such as chronic ulcerative stomatitis and lichen planus pemphigoid, which may exhibit some lichenoid features clinically or histologically. In this context, direct immunofluorescence is of great value. Therefore, the lack of precise diagnosis in studies likely altered the reported prevalence of OLP. A more fundamental concern is that study participants were typically examined only once; therefore, the prevalence of OLP may be underestimated because of the fluctuating nature of the disease. In many patients, the onset of OLP was insidious, and they may have been unaware of their oral condition. Those with mild or moderate OLP might not have sought medical treatment, especially for the nonerosive type of OLP, which manifests no discomfort in approximately one-third of individuals, or they may have only roughness of the lining of the mouth, resulting in false low prevalence estimates in studies.13,69 In addition, methodological heterogeneity is important to consider. Prevalence and incidence data may be derived from various study designs with differing levels of methodological quality, such as different study populations, sampling methods, coverage of the identified sample, sample sizes, data collection, participant cooperation, and professional level of the examiner, resulting in differences among the studies.
Quiz Ref IDSubgroup analysis by continent confirmed a lower prevalence of OLP in Asian countries than in non-Asian countries. The highest prevalence (6.04%) was reported for a sample in Brazil,46 whereas the lowest prevalence (0.02%) was reported for a sample in India.18 A possible explanation for this variation might be socioeconomic and sociocultural differences between the populations. Another potential reason may be differences in the screening methods used as well as variations in the prevalence of OLP among the general population of the respective countries. Regional variation, seasonal and climate differences, lifestyle habits (eg, smoking and drinking), eating habits (eg, a spicy diet or the manner of chewing), and life stresses have important roles in the prevalence of OLP. Smokers and patients who abuse alcohol have a higher prevalence of OLP.4 This factor may explain why the highest prevalence of OLP (6.04%) was found in Brazil, where 18.18% of residents report being smokers and 29.09% report consumption of alcoholic beverages.46
Quiz Ref IDSubgroup analysis by sex showed that the prevalence of OLP was higher among women than among men. Possible reasons are that female hormone levels, such as estrogen and progesterone, tend to fluctuate, especially during menstruation or menopause, and that different social roles may lead to the body being in a state of stress. One study70 demonstrated that the incidence of OLP is higher in perimenopausal women than in the general population and increases statistically significantly with greater severity of depression. Oral lichen planus in perimenopausal women can be mediated by declining levels of estrogen and progesterone that directly or indirectly may cause depression, which can trigger OLP. An additional explanation may be that OLP is a T-cell–mediated immunological disease. Another study71 demonstrated that women are more susceptible to some immune-mediated inflammatory diseases than men (eg, systemic lupus erythematosus, rheumatoid arthritis, and dermatomyositis).
Quiz Ref IDSubgroup analysis by age indicated that the prevalence of OLP was higher among patients 40 years and older than among patients younger than 40 years. This difference could be attributed to long-standing oral habits. In addition, the oral mucosa undergoes age-related changes (eg, thinning of mucosa, decreased elasticity, less saliva secretion, and greater tissue permeability),72 increasing the risk of OLP. Furthermore, older individuals may not pay as much attention to their oral health. Finally, OLP may also be associated with metabolic changes during aging or with decreased immunity, nutritional deficiencies, medication use, or denture wear.
The high statistical heterogeneity in our study suggests that differences in prevalence estimates between the studies cannot be explained by random chance alone. Rather, the differences in prevalence estimates may be altered by factors like publication bias, difficulty in diagnosing OLP, different demographic characteristics, and regional disparity among the studies.
There are several limitations of our systematic review and meta-analysis. First, random error is always a concern, although our analysis was based on a total of 654 956 individuals. We did not have access to some databases (eg, the grey literature), which may have allowed us to obtain additional epidemiological information. Second, few studies have reported a detailed age stratification. Third, early studies31,60,61 in particular had 1 or more of the following defects with respect to the accuracy of diagnoses: lack of accepted clinical criteria, absence of or no criteria for histological verification, missing immunofluorescence examination, or omitted differential diagnosis.
This study identified the global prevalence and incidence of OLP in terms of its spatial, temporal, and population distribution. We estimated that the overall pooled prevalence of OLP was 0.89% among the general population and 0.98% among clinical patients. A higher prevalence of OLP was found in non-Asian countries, among women, and among people 40 years and older. Our findings should be considered with caution because of the high heterogeneity of the included studies.
Accepted for Publication: October 13, 2019.
Corresponding Author: Liming Lu, PhD, Clinical Research Center, South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, 232 Waihuan Dong Rd, Guangzhou 510006, China (lulimingleon@126.com); Zhiwei Chen, MD, Department of Dermatology, Wenzhou Hospital of Integrated Chinese and Western Medicine, Zhejiang University of Traditional Chinese Medicine, 75 Jin Xiu Rd, Wenzhou, Zhejiang 325000, China (wz75czw@163.com).
Published Online: January 2, 2020. doi:10.1001/jamadermatol.2019.3797
Author Contributions: Drs Chen and Lu had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Drs Li and Tang contributed equally to this work.
Concept and design: Li, Tang, Chen, Lu.
Acquisition, analysis, or interpretation of data: Li, Tang, Zheng, Wen, Ge, Lin, Lu.
Drafting of the manuscript: Li, Tang, Zheng, Wen.
Critical revision of the manuscript for important intellectual content: Li, Tang, Zheng, Ge, Lin, Chen, Lu.
Statistical analysis: Li, Tang, Zheng, Wen, Lu.
Obtained funding: Zheng, Lu.
Administrative, technical, or material support: Lu.
Supervision: Wen, Chen, Lu.
Conflict of Interest Disclosures: None reported.
Funding/Support: This work was funded by the First-Class Discipline Construction Foundation of Guangzhou University of Chinese Medicine (Chinese Medicine Department), the Young Top Talent Project of Scientific and Technological Innovation in Special Support Plan for Training High-level Talents in Guangdong (grant 2017TQ04R627), and the Youth Research and Cultivation Project of Guangzhou University of Chinese Medicine (grant A1-AFD018191A40).
Role of the Funder/Sponsor: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
2.Mozaffari
HR, Rahmani
M, Rezaei
F, Sadeghi
M, Sharifi
R, Ejtehadi
A. Evaluation of oral lichen planus frequency in patients referred to pathology centers of Kermanshah city, during 2008 to 2011.
Scholars Journal of Applied Medical Sciences. 2016;4(6):2200-2202. doi:
10.21276/sjams.2016.4.6.68Google ScholarCrossref 3.Gorouhi
F, Davari
P, Fazel
N. Cutaneous and mucosal lichen planus: a comprehensive review of clinical subtypes, risk factors, diagnosis, and prognosis.
ScientificWorldJournal. 2014;2014:742826. doi:
10.1155/2014/742826PubMedGoogle Scholar 5.Soto Araya
M, Rojas Alcayaga
G, Esguep
A. Association between psychological disorders and the presence of oral lichen planus, burning mouth syndrome and recurrent aphthous stomatitis.
Med Oral. 2004;9(1):1-7.
PubMedGoogle ScholarCrossref 10.Vučićević Boras
V, Savage
NW, Brailo
V,
et al. The significance of oral and systemic factors in Australian and Croatian patients with oral lichen planus.
Acta Dermatovenerol Croat. 2014;22(2):97-102.
PubMedGoogle Scholar 33.Al-Maweri
SA, Al-Jamaei
A, Saini
R, Laronde
DM, Sharhan
A. White oral mucosal lesions among the Yemeni population and their relation to local oral habits.
J Investig Clin Dent. 2018;9(2):e12305. doi:
10.1111/jicd.12305PubMedGoogle Scholar 34.Tortorici
S, Corrao
S, Natoli
G, Difalco
P. Prevalence and distribution of oral mucosal non-malignant lesions in the western Sicilian population.
Minerva Stomatol. 2016;65(4):191-206.
PubMedGoogle Scholar 37.Gupta
S, Singh
R, Gupta
OP, Tripathi
A. Prevalence of oral cancer and pre-cancerous lesions and the association with numerous risk factors in North India: a hospital based study.
Natl J Maxillofac Surg. 2014;5(2):142-148. doi:
10.4103/0975-5950.154816PubMedGoogle ScholarCrossref 41.do Carmo
MA, Gleber-Netto
FO, Romano
ML, Caldeira
PC, de Aguiar
MC. Clinical and demographic overlaps among immunologically mediated oral diseases: a challenge for clinicians.
Gen Dent. 2014;62(1):67-72.
PubMedGoogle Scholar 42.Bhatnagar
P, Rai
S, Bhatnagar
G, Kaur
M, Goel
S, Prabhat
M. Prevalence study of oral mucosal lesions, mucosal variants, and treatment required for patients reporting to a dental school in North India: in accordance with WHO guidelines.
J Family Community Med. 2013;20(1):41-48. doi:
10.4103/2230-8229.108183PubMedGoogle ScholarCrossref 43.Brzak
BL, Mravak-Stipetić
M, Canjuga
I,
et al. The frequency and malignant transformation rate of oral lichen planus and leukoplakia: a retrospective study.
Coll Antropol. 2012;36(3):773-777.
PubMedGoogle Scholar 48.Cebeci
I, Gülşahi
A, Kamburoğlu
K,
et al. Oral lichen planus in Turkish patients: prevalence and clinical and histopathologic characteristics.
Turkiye Klinikleri J Med Sci. 2009;29:1071-1075.
Google Scholar 51.Delilbaşi
C, Akman
H, Redzep
E, Akal
U. Prevalence of oral precancerous lesions in a selected Turkish population.
Turk J Med Sci. 2003;33(1):39-42.
Google Scholar 53.Bokor-Bratić
M, Picuric
I. The prevalence of precancerous oral lesions: oral lichen planus.
Arch Oncol. 2001;9(2):107-109.
Google Scholar 54.Femopase
FL, Binagui
MV, López de Blanc
S, Gandolfo
M, Lanfranchi
HE. A comparative study of oral lichen planus and leukoplakia in two Argentine populations.
Acta Odontol Latinoam. 1997;10(2):89-99.
PubMedGoogle Scholar 61.Pindborg
JJ, Chawla
TN, Misra
RK, Nagpaul
RK, Gupta
VK. Frequency of oral carcinoma, leukoplakia, leukokeratosis, leukoedema, submucous fibrosis, and lichen planus in 10,000 Indians in Lucknow, Uttar Pradesh, India: preliminary report.
J Dent Res. 1965;44(3):61. doi:
10.1177/00220345650440032901PubMedGoogle ScholarCrossref 62.Hegde
MN, Jain
R, Punja
A. Prevalence of oral mucosal lesions and their co-relation to habits in patients visiting a dental school of South Karnataka: a cross sectional survey: 2012.
Nitte University J Health Sci. 2014;4(4):69-72.
Google Scholar 63.Munn
Z, Moola
S, Lisy
K, Riitano
D, Tufanaru
C. Methodological guidance for systematic reviews of observational epidemiological studies reporting prevalence and cumulative incidence data.
Int J Evid Based Healthc. 2015;13(3):147-153. doi:
10.1097/XEB.0000000000000054PubMedGoogle ScholarCrossref 65.Cucchetti
A, Cappelli
A, Mosconi
C,
et al. Improving patient selection for selective internal radiation therapy of intra-hepatic cholangiocarcinoma: a meta-regression study.
Liver Int. 2017;37(7):1056-1064. doi:
10.1111/liv.13382PubMedGoogle ScholarCrossref 66.Bhonsle
RB, Pindborg
JJ, Gupta
PC, Murti
PR, Mehta
FS. Incidence rate of oral lichen planus among Indian villagers.
Acta Derm Venereol. 1979;59(3):255-257.
PubMedGoogle Scholar 70.Mohan
RPS, Gupta
A, Kamarthi
N, Malik
S, Goel
S, Gupta
S. Incidence of oral lichen planus in perimenopausal women: a cross-sectional study in Western Uttar Pradesh population.
J Midlife Health. 2017;8(2):70-74. doi:
10.4103/jmh.JMH_34_17PubMedGoogle Scholar