Risk Factors for Lichen Sclerosus: A Case-Control Study of 43,000 Finnish Women.

OBJECTIVES: Lichen sclerosus (LS) is an inflammatory skin disease probably arising from an interplay of genetics, local irritation, and autoimmune processes. We identified potential risk factors for the disease using data from nationwide Finnish registries. METHODS: We identified all women diagnosed with LS within specialized health care during 1998-2016 (n = 10,692) and selected 3 age-matched population control women for each case. We calculated odds ratios (ORs) for possible risk factors using conditional logistic regression. RESULTS: Dermatological autoimmune conditions were strongly associated with LS (OR = 15.1, 95% confidence interval [CI] = 13.6-16.7 for morphea; OR = 10.3, 95% CI = 5.02-19.0 for lichen planus; OR = 6.86, 95% CI = 5.65-8.33 for alopecia; OR = 2.20, 95% CI = 1.88-2.56 for vitiligo). A diagnosis of Crohn or celiac disease increased the odds of LS (OR = 1.80, 95% CI = 1.71-1.89; OR = 1.49, 95% CI = 1.28-1.73, respectively) as did urge and stress incontinence (OR = 1.79, 95% CI = 1.71-1.87; OR = 1.28, 95% CI = 1.22-1.35, respectively).The odds of LS were lower in women after a diagnosis of type 1 diabetes (OR = 0.43, 95% CI = 0.41-0.45), coronary artery disease (OR = 0.41, 95% CI = 0.38-0.43), and rheumatoid arthritis (OR = 0.38, 95% CI = 0.36-0.41).Parous women had higher odds of LS (OR = 1.11, 95% CI = 1.04-1.17) than nulliparous ones, but increasing number of births decreased the risk. Lichen sclerosus was not associated with socioeconomic status nor the urbanicity level of the place of residence. CONCLUSIONS: Certain autoimmune diseases and urinary incontinence were associated with LS.

Incidence of Lichen Planus and Subsequent Mortality in Finnish Women.

The incidence pattern of lichen planus (LP) and LP-related mortality are unknown. The aim of this study was to assess these factors, based on Finnish nationwide registry data including 13,378 women with LP diagnosed during 1969 to 2012. The incidence rate for LP in 2003 to 2012 was 28 per 100,000 woman-years age-adjusted to the European Standard Population. Mortality was assessed using the standardized mortality ratio (SMR) with national mortality rates as the reference. All-cause mortality was increased (SMR 1.07, 95% confidence interval (95% CI) 1.02-1.11), with excess mortality from Hodgkin lymphoma (SMR 6.73, 95% CI 1.83-17.2), non-Hodgkin lymphoma (SMR 1.68, 95% CI 1.11-2.44), cancer of the oral cavity (SMR 10.5, 95% CI 5.99-17.0), cancer of the tongue (SMR 7.25, 95% CI 3.13-14.3), infections (SMR 1.78, 95% CI 1.14-2.64), respiratory diseases (SMR 1.31, 95% CI 1.07-1.57), and diseases of the digestive system (SMR 1.39, 95% CI 1.09-1.75). In conclusion, LP is a common disease and patients seem to have an impaired long-term prognosis.

Cancer risk of Lichen planus: A cohort study of 13,100 women in Finland.

The association between Lichen planus (LP) and cancer has been under debate for decades. We studied the connection via population-based Finnish register data. All women with the diagnosis of LP (n = 13,100) were identified from the Finnish Hospital Discharge Registry from 1969-2012. These patients were linked with subsequent cancer diagnoses from the Finnish Cancer Registry until 2014. Standardized incidence ratios (SIRs) were counted for different cancers by dividing the observed numbers of cancers by expected numbers, which were based on national cancer incidence rates. In total, 1,520 women with LP were diagnosed with cancer (SIR 1.15, 95% confidence interval [CI] 1.09-1.20). LP was associated with an increased risk of cancer of lip (SIR 5.17, 95% CI 3.06-8.16), cancer of tongue (SIR 12.4, 95% CI 9.45-16.0), cancer of oral cavity (SIR 7.97, 95% CI 6.79-9.24), cancer of esophagus (SIR 1.95, 95% CI 1.17-3.04), cancer of larynx (SIR of 3.47, 95% CI 1.13-8.10) and cancer of vulva (SIR 1.99, 95% CI 1.18-3.13). The risk of cancer was not increased in other locations where LP manifests (pharynx and skin). Patients with diagnosed LP have an increased risk of developing cancer of lip, tongue, oral cavity, esophagus, larynx and vulva. These data are important when considering treatment and follow-up of patients with LP diagnosis.

Lichen sclerosus and risk of cancer.

Malignant potential of lichen sclerosus (LS) has been suspected, but evidence is sparse. We used the population-based Finnish Cancer Registry data to further study this connection. We identified all women with the diagnosis of LS (n = 7,616) listed in the Finnish Hospital Discharge Registry from 1970 to 2012. The cohort was followed through the Finnish Cancer Registry for subsequent cancer diagnoses until 2014. Standardized incidence ratios (SIRs) were calculated for different cancers by dividing the observed numbers of cancers by expected ones. The expected numbers were based on national cancer incidence rates. During the follow-up period, we found 812 cancers among patients with LS (SIR: 1.13, 95% CI 1.05-1.21). LS was associated with an increased risk of vulvar (182 cases, SIR: 33.6, 95% CI 28.9-38.6) and vaginal cancer (4 cases, SIR: 3.69, 95% CI 1.01-9.44). The risk of cancers of the uterine cervix and lung was significantly decreased. LS is associated with an increased risk for vulvar and vaginal cancer. These data are important when designing the care of women diagnosed with LS.