Menopausal hormone therapy and risk of sarcoidosis: a population-based nested case-control study in Sweden.

Sarcoidosis incidence peaks in women between 50 and 60 years old, which coincides with menopause, suggesting that certain sex hormones, mainly estrogen, may play a role in disease development. We investigated whether menopausal hormone therapy (MHT) was associated with sarcoidosis risk in women and whether the risk varied by treatment type. We performed a nested case-control study (2007-2020) including incident sarcoidosis cases from the Swedish National Patient Register (n = 2593) and matched (1:10) to general population controls (n = 20,003) on birth year, county, and living in Sweden at the time of sarcoidosis diagnosis. Dispensations of MHT were obtained from the Swedish Prescribed Drug Register before sarcoidosis diagnosis/matching. Adjusted odds ratios (aOR) of sarcoidosis were estimated using conditional logistic regression. Ever MHT use was associated with a 25% higher risk of sarcoidosis compared with never use (aOR 1.25, 95% CI 1.13-1.38). When MHT type and route of administration were considered together, systemic estrogen was associated with the highest risk of sarcoidosis (aOR 1.51, 95% CI 1.23-1.85), followed by local estrogen (aOR 1.25, 95% CI 1.11-1.42), while systemic estrogen-progestogen combined was associated with the lowest risk compared to never users (aOR 1.12, 95% CI 0.96-1.31). The aOR of sarcoidosis did not differ greatly by duration of MHT use. Our findings suggest that a history of MHT use is associated with increased risk of sarcoidosis, with women receiving estrogen administered systemically having the highest risk.

Sarcoidosis: Epidemiology and clinical insights.

Sarcoidosis is characterized by noncaseating granulomas which form in almost any part of the body, primarily in the lungs and/or thoracic lymph nodes. Environmental exposures in genetically susceptible individuals are believed to cause sarcoidosis. There is variation in incidence and prevalence by region and race. Males and females are almost equally affected, although disease peaks at a later age in females than in males. The heterogeneity of presentation and disease course can make diagnosis and treatment challenging. Diagnosis is suggestive in a patient if one or more of the following is present: radiologic signs of sarcoidosis, evidence of systemic involvement, histologically confirmed noncaseating granulomas, sarcoidosis signs in bronchoalveolar lavage fluid (BALF), and low probability or exclusion of other causes of granulomatous inflammation. No sensitive or specific biomarkers for diagnosis and prognosis exist, but there are several that can be used to support clinical decisions, such as serum angiotensin-converting enzyme levels, human leukocyte antigen types, and CD4 Vα2.3+ T cells in BALF. Corticosteroids remain the mainstay of treatment for symptomatic patients with severely affected or declining organ function. Sarcoidosis is associated with a range of adverse long-term outcomes and complications, and with great variation in prognosis between populations. New data and technologies have moved sarcoidosis research forward, increasing our understanding of the disease. However, there is still much left to be discovered. The pervading challenge is how to account for patient variability. Future studies should focus on how to optimize current tools and develop new approaches so that treatment and follow-up can be targeted to individuals with more precision.

Peripheral blood lymphopenia in sarcoidosis associates with HLA-DRB1 alleles but not with lung immune cells and organ involvement.

Different human leukocyte antigen (HLA) alleles associate with disease phenotypes in sarcoidosis. Peripheral blood (PB) lymphopenia is reported as more common in sarcoidosis patients with worse prognosis. The mechanisms behind are unrecognized but a PB depletion due to lymphocytes migrating to lung and/or extra pulmonary organs has been suggested. Insights into associations between HLA alleles, lung immune cells, clinical phenotype including extra pulmonary manifestations (EPM), and PB lymphopenia may provide mechanistic clues and enable adequate intervention in this patient group. In this situdy,141 treatment naïve, newly diagnosed patients were retrospectively identified in a Swedish cohort of sarcoidosis patients. Data on HLA-DRB1 alleles, lung immune cells from bronchoalveolar lavage fluid (BALF), PB lymphocytes and clinical parameters including treatment and disease course (chronic vs. resolving) were collected. The patients were followed for 2 years. PB lymphopenia associated with male sex, development of non-resolving disease, a need for first- and second-line systemic immunosuppressant treatment and HLA- DRB1*07. No correlation between BALF and PB lymphocytes, and no difference in EPM was detected between patients with and without PB lymphopenia. In conclusion, PB lymphopenia is associated with a more severe disease phenotype and carriage of the HLA-DRB1*07 allele. The results do not lend support to the hypothesis about sarcoidosis PB lymphopenia being due to a migration of PB lymphocytes to other organs. Rather, they provide a basis for future studies on the connection between HLA-DRB1*07 and PB lymphopenia mechanisms.

Reproductive and hormonal risk factors for sarcoidosis: a nested case-control study.

BACKGROUND: Sarcoidosis incidence peaks in females around the fifth decade of life, which coincides with menopause, suggesting hormonal factors play a role in disease development. We investigated whether longer exposure to reproductive and hormonal factors is associated with reduced sarcoidosis risk. METHODS: We conducted a matched case-control study nested within the Mammography Screening Project. Incident sarcoidosis cases were identified via medical records and matched to controls on birth and questionnaire date (1:4). Information on hormonal factors was obtained through questionnaires prior to sarcoidosis diagnosis. Multilevel modelling was used to estimate adjusted odds ratios with 95% credible intervals (OR; 95% CI). RESULTS: In total, 32 sarcoidosis cases and 124 controls were included. Higher sarcoidosis odds were associated with older age at menarche (OR 1.19: 95% CI 0.92-1.55), natural menopause versus non-natural (OR 1.53: 95% CI 0.80-2.93), later age at first pregnancy (OR 1.11: 95% CI 0.76-1.63) and ever hormone replacement therapy (HRT) use (OR 1.40: 95% CI 0.76-2.59). Lower odds were associated with older age at menopause (OR 0.90: 95% CI 0.52-1.55), longer duration of oral contraceptive use (OR 0.70: 95% CI 0.45-1.07), longer duration of HRT use (OR 0.61: 95% CI 0.22-1.70), ever local estrogen therapy (LET) use (OR 0.83: 95% CI 0.34-2.04) and longer duration of LET use (OR 0.78: 95% CI 0.21-2.81). However, the CIs could not rule out null associations. CONCLUSION: Given the inconsistency and modest magnitude in our estimates, and that the 95% credible intervals included one, it still remains unclear whether longer estrogen exposure is associated with reduced sarcoidosis risk.

Monocytes in sarcoidosis are potent tumour necrosis factor producers and predict disease outcome.

BACKGROUND: Pulmonary sarcoidosis is an inflammatory disease characterised by granuloma formation and heterogeneous clinical outcome. Tumour necrosis factor (TNF) is a pro-inflammatory cytokine contributing to granuloma formation and high levels of TNF have been shown to associate with progressive disease. Mononuclear phagocytes (MNPs) are potent producers of TNF and highly responsive to inflammation. In sarcoidosis, alveolar macrophages have been well studied. However, MNPs also include monocytes/monocyte-derived cells and dendritic cells, which are poorly studied in sarcoidosis, despite their central role in inflammation. OBJECTIVE: To determine the role of pulmonary monocyte-derived cells and dendritic cells during sarcoidosis. METHODS: We performed in-depth phenotypic, functional and transcriptomic analysis of MNP subsets from blood and bronchoalveolar lavage (BAL) fluid from 108 sarcoidosis patients and 30 healthy controls. We followed the clinical development of patients and assessed how the repertoire and function of MNP subsets at diagnosis correlated with 2-year disease outcome. RESULTS: Monocytes/monocyte-derived cells were increased in blood and BAL of sarcoidosis patients compared to healthy controls. Interestingly, high frequencies of blood intermediate monocytes at time of diagnosis associated with chronic disease development. RNA sequencing analysis showed highly inflammatory MNPs in BAL of sarcoidosis patients. Furthermore, frequencies of BAL monocytes/monocyte-derived cells producing TNF without exogenous stimulation at time of diagnosis increased in patients that were followed longitudinally. In contrast to alveolar macrophages, the frequency of TNF-producing BAL monocytes/monocyte-derived cells at time of diagnosis was highest in sarcoidosis patients that developed progressive disease. CONCLUSION: Our data show that pulmonary monocytes/monocyte-derived cells are highly inflammatory and can be used as a predictor of disease outcome in sarcoidosis patients.

Positive Predictive Value of Sarcoidosis Identified in an Administrative Healthcare Registry: A Validation Study.

BACKGROUND: International classification of disease (ICD) codes used to study sarcoidosis has previously been validated in only 1 study. We aimed to determine the accuracy of ICD codes to identify true sarcoidosis diagnoses in Sweden. METHODS: We identified adults with at least 2 ICD codes for sarcoidosis (ICD-10 D86) at Karolinska University Hospital 2010-2013 from the National Patient Register. Of these, we randomly sampled 100 patients for validation. We collected clinical data and categorized the diagnosis of sarcoidosis as definite, probable, or unlikely. We estimated the positive predictive value for definite and probable sarcoidosis-identified with at least 2 ICD codes-with 95% confidence intervals. RESULTS: We deemed 77% of the cases to be definite and 17% to be probable. The positive predictive value was 0.94 (95% confidence intervals = 0.87 to 0.98). CONCLUSIONS: Using at least 2 visits listing an ICD-10 code for sarcoidosis accurately identified patients with sarcoidosis from administrative health data in Sweden.

Methylome and transcriptome signature of bronchoalveolar cells from multiple sclerosis patients in relation to smoking.

BACKGROUND: Despite compelling evidence that cigarette smoking impacts the risk of developing multiple sclerosis (MS), little is known about smoking-associated changes in the primary exposed lung cells of patients. OBJECTIVES: We aimed to examine molecular changes occurring in bronchoalveolar lavage (BAL) cells from MS patients in relation to smoking and in comparison to healthy controls (HCs). METHODS: We profiled DNA methylation in BAL cells from female MS (n = 17) and HC (n = 22) individuals, using Illumina Infinium EPIC and performed RNA-sequencing in non-smokers. RESULTS: The most prominent changes were found in relation to smoking, with 1376 CpG sites (adjusted P < 0.05) differing between MS smokers and non-smokers. Approximately 30% of the affected genes overlapped with smoking-associated changes in HC, leading to a strong common smoking signature in both MS and HC after gene ontology analysis. Smoking in MS patients resulted in additional discrete changes related to neuronal processes. Methylome and transcriptome analyses in non-smokers suggest that BAL cells from MS patients display very subtle (not reaching adjusted P < 0.05) but concordant changes in genes connected to reduced transcriptional/translational processes and enhanced cellular motility. CONCLUSIONS: Our study provides insights into the impact of smoking on lung inflammation and immunopathogenesis of MS.

Infection risk in sarcoidosis patients treated with methotrexate compared to azathioprine: A retrospective 'target trial' emulated with Swedish real-world data.

BACKGROUND AND OBJECTIVE: No clinical trial has examined the risk of infection associated methotrexate and azathioprine, two advocated treatments for sarcoidosis. We aimed to compare the 6-month risk of infection after the initiation of methotrexate or azathioprine. METHODS: We conducted a retrospective target trial emulation using Swedish pre-existing data. We searched for eligible participants who were dispensed methotrexate or azathioprine in the Prescribed Drug Register (PDR) every day between January 2007 and June 2013. Adults were eligible if they had ≥2 ICD-coded visits for sarcoidosis in the National Patient Register (NPR) and were dispensed ≥1 systemic corticosteroid but no methotrexate or azathioprine in the past 6 months (PDR). Within 6 months of methotrexate or azathioprine initiation, diagnosis of infectious disease was identified (visit in the NPR where infectious disease was the primary diagnosis). We estimated RR and risk differences comparing methotrexate (n = 667) to azathioprine initiations (n = 259) using targeted maximum likelihood estimation (TMLE) adjusting for demographic factors, comorbidity and sarcoidosis severity proxies. RESULTS: There were 43 infections in the methotrexate group (adjusted 6-month risk 6.8%) and 29 infections in the azathioprine group (12.0%). The RR for infectious disease at 6 months associated with methotrexate compared to azathioprine initiation was 0.57 (95% CI: 0.39, 0.82) and the risk difference was -5.2% (95% CI: -8.5%, -1.8%). The RR at 9 months was attenuated to 0.77 (95% CI: 0.52, 1.14). CONCLUSION: Methotrexate appears to be associated with a lower risk of infection in sarcoidosis than azathioprine, but randomized trials should confirm this finding.

Risk of first and recurrent serious infection in sarcoidosis: a Swedish register-based cohort study.

Serious infections impair quality of life and increase costs. Our aim was to determine if sarcoidosis is associated with a higher rate of serious infection and whether this varies by age, sex, time since diagnosis or treatment status around diagnosis.We compared individuals with sarcoidosis (at least two International Classification of Diseases codes in the Swedish National Patient Register 2003-2013; n=8737) and general population comparators matched 10:1 on age, sex and residential location (n=86 376). Patients diagnosed in 2006-2013 who were dispensed at least one immunosuppressant ±3 months from diagnosis (Swedish Prescribed Drug Register) were identified. Cases and comparators were followed in the National Patient Register for hospitalisations for infection. Using Cox and flexible parametric models, we estimated adjusted hazard ratios (aHR) and 95% confidence intervals for first and recurrent serious infections (new serious infection >30 days after previous).We identified 895 first serious infections in sarcoidosis patients and 3881 in comparators. The rate of serious infection was increased 1.8-fold in sarcoidosis compared to the general population (aHR 1.81, 95% CI 1.65-1.98). The aHR was higher in females than males and during the first 2 years of follow-up. Sarcoidosis cases treated with immunosuppressants around diagnosis had a three-fold increased risk, whereas nontreated patients had a 50% increased risk. The rate of serious infection recurrence was 2.8-fold higher in cases than in comparators.Serious infections are more common in sarcoidosis than in the general population, particularly during the first few years after diagnosis. Patients who need immunosuppressant treatment around diagnosis are twice as likely to develop a serious infection than those who do not.

Lung CD4+ Vα2.3+ T-cells in sarcoidosis cohorts with Löfgren's syndrome.

BACKGROUND: Sarcoidosis is diagnosed by a combination of typical clinical and radiological findings together with biopsy proof of non-caseating epithelioid cell granulomas in affected tissues and/or the cell distribution in bronchoalveolar lavage fluid (BALF). We aimed at investigating the usefulness of measuring the proportion of T-cell receptor (TCR) CD4+ Vα2.3+ T-cells in BALF as an additive marker to CD4/CD8-ratio to confirm the diagnosis. METHODS: From a register consisting of 749 sarcoidosis patients [Löfgren's syndrome (LS) n = 274, non-LS n = 475] with information on Vα2.3+ T-cells, an expansion of CD4+ Vα2.3+ T-cells (CD4+ Vα2.3+ T cells > 10.5% in BALF) was seen in 268 (36%). Controls were healthy volunteers (n = 69) and patients with other pulmonary conditions (n = 39), investigated because of suspicion of sarcoidosis. RESULTS: A proportion of CD4+ Vα2.3+ T-cells in BALF > 10.5% was highly specific for sarcoidosis, with a specificity of 97% and with a sensitivity of 36% (p < 0.0001). Receiver operating characteristic (ROC) curves show that testing for CD4+ Vα2.3+ T-cells in BALF was a more useable test in individuals with LS [area under the curve (AUC) 0.82, p < 0.0001] compared to the whole patient group (AUC 0.64, p < 0.0001). CONCLUSION: In this study, we show that an increased proportion of CD4+ Vα2.3+ T-cells in BALF is highly specific for sarcoidosis. This suggests that this T-cell subset could be used as an additional tool to the CD4/CD8-ratio to support the sarcoidosis diagnosis, particularly in patients with LS but also in patients with non-LS.

Maternal and infant outcomes in sarcoidosis pregnancy: a Swedish population-based cohort study of first births.

BACKGROUND: It is unclear whether sarcoidosis, a multisystem inflammatory disease, is associated with adverse pregnancy outcomes. We aimed to assess the risk of adverse maternal and infant outcomes in sarcoidosis pregnancies, focused on first births. METHODS: Using a population-based cohort study design and Swedish national registers (2002-2013), we identified 182 singleton first pregnancies in the Medical Birth Register with at least two maternal ICD-coded sarcoidosis visits prior to pregnancy in the National Patient Register. Modified Poisson regression models estimated relative risks (RR) of adverse outcomes in sarcoidosis pregnancies compared to the general population adjusted for maternal age at delivery, calendar year and educational level. Some models were additionally adjusted for maternal body mass index and smoking status. RESULTS: The prevalence of pre-existing diabetes and hypertension was higher in mothers with sarcoidosis than those without sarcoidosis. Mothers with sarcoidosis had an increased risk of preeclampsia/eclampsia (RR 1.6; 95%CI 1.0, 2.6) and cesarean delivery (RR 1.3; 95%CI 1.0, 1.6). There were < 5 stillbirths and cases of infection and no cases of placental abruption, venous thromboembolism, cardiac arrest or maternal death. Newborns of first-time mothers with sarcoidosis had a 70% increased risk of preterm birth (RR 1.7; 95%CI 1.1, 2.5). There was an increased risk of birth defects (RR 1.6; 95%CI 0.9, 2.8) the majority of which were non-cardiac. CONCLUSIONS: Sarcoidosis is associated with increased risks for preeclampsia/eclampsia, cesarean delivery, preterm birth and some birth defects. Awareness of these conditions may prevent possible pregnancy complications in mothers with sarcoidosis and their newborns.

Are infectious diseases risk factors for sarcoidosis or a result of reverse causation? Findings from a population-based nested case-control study.

Findings from molecular studies suggesting that several infectious agents cause sarcoidosis are intriguing yet conflicting and likely biased due to their cross-sectional design. As done in other inflammatory diseases to overcome this issue, prospectively-collected register data could be used, but reverse causation is a threat when the onset of disease is difficult to establish. We investigated the association between infectious diseases and sarcoidosis to understand if they are etiologically related. We conducted a nested case-control study (2009-2013) using incident sarcoidosis cases from the Swedish National Patient Register (n = 4075) and matched general population controls (n = 40,688). Infectious disease was defined using inpatient/outpatient visits and/or antimicrobial dispensations starting 3 years before diagnosis/matching. Adjusted odds ratios (aOR) of sarcoidosis were estimated using conditional logistic regression and tested for robustness assuming the presence of reverse causation bias. The aOR of sarcoidosis associated with history of infectious disease was 1.19 (95% confidence interval [CI] 1.09, 1.29; 21% vs. 16% exposed cases and controls, respectively). Upper respiratory and ocular infections conferred the highest OR. Findings were similar when we altered the infection definition or varied the infection-sarcoidosis latency period (1-7 years). In bias analyses assuming one in 10 infections occurred because of preclinical sarcoidosis, the observed association was completely attenuated (aOR 1.02; 95% CI 0.90, 1.15). Our findings, likely induced by reverse causation due to preclinical sarcoidosis, do not support the hypothesis that common symptomatic infectious diseases are etiologically linked to sarcoidosis. Caution for reverse causation bias is required when the real disease onset is unknown.

Sarcoidosis mortality in Sweden: a population-based cohort study.

We aimed to investigate sarcoidosis mortality in a large, population-based cohort, taking into account disease heterogeneity.Individuals with incident sarcoidosis (n=8207) were identified from the Swedish National Patient Register using International Classification of Disease codes (2003‒2013). In a subset, cases receiving treatment ±3 months from diagnosis were identified from the Prescribed Drug Register. Nonsarcoidosis comparators from the general population were matched to cases 10:1 on birth year, sex and county. Individuals were followed for all-cause death in the Cause of Death Register. Adjusted mortality rates, rate differences and hazard ratios (HRs) were estimated, stratifying by age, sex and treatment status.The mortality rate was 11.0 per 1000 person-years in sarcoidosis versus 6.7 in comparators (rate difference 2.7 per 1000 person-years). The HR for death was 1.61 (95% CI 1.47‒1.76), with no large variation by age or sex. For cases not receiving treatment within the first 3 months, the HR was 1.13 (95% CI 0.94‒1.35). The HR was 2.34 (95% CI 1.99‒2.75) for those receiving treatment.Individuals with sarcoidosis are at a higher risk of death compared to the general population. For the majority, the increased risk is small. However, patients whose disease leads to treatment around diagnosis have a two-fold increased risk of death. Future interventions should focus on this vulnerable group.

Familial aggregation and heritability of sarcoidosis: a Swedish nested case-control study.

Sarcoidosis is believed to be caused by both genetic and environmental risk factors, but the proportion of the susceptibility to sarcoidosis that is mediated by genetics remains unknown. We aimed to estimate the familial aggregation and heritability of sarcoidosis using a case-control-family study design and population-based Swedish registers.We identified 23 880 individuals with visits for sarcoidosis in the Swedish National Patient Register using International Classification of Diseases codes (1964‒2013). Information on Löfgren's syndrome was available for a subset diagnosed at Karolinska University Hospital (Stockholm, Sweden). General population controls were matched to cases (10:1). Relatives of cases and controls were identified from the Swedish Multi-Generation Register and ascertained for sarcoidosis in the National Patient Register. We estimated familial relative risks for sarcoidosis using conditional logistic regression and heritability using biometric models.Having at least one first-degree relative with sarcoidosis was associated with a 3.7-fold increase in the risk of sarcoidosis (95% CI 3.4-4.1). The relative risk increased in those with two or more relatives (relative risk 4.7) and in Löfgren's syndrome (relative risk 4.1). The heritability was 39% (95% CI 12-65%).This large investigation showed that having a relative with sarcoidosis is a very strong risk factor for the disease. Genetic variation is an important, albeit partial, contributing factor to the risk for sarcoidosis.

T-cell activation and HLA-regulated response to smoking in the deep airways of patients with multiple sclerosis.

Cigarette smoking is a risk factor for multiple sclerosis (MS), and the risk is further multiplied for HLA-DRB1*15(+) smokers. To define the smoke-induced immune responses in the lung we performed bronchoscopy with bronchoalveolar lavage (BAL) on smokers and non-smokers, both MS-patients and healthy volunteers. In the BAL, non-smokers with MS showed an increased preformed CD40L expression in CD4(+) T-cells while smokers displayed an increase in proliferating (Ki-67(+)) T-cells. In addition, our results confirm that smoking induces an increase of alveolar macrophages in BAL, and further defined a significant attenuation of this response in carriers of the HLA-DRB1*15 allele, in both MS patients and healthy controls. This first systematic investigation of the immune response in the lungs of smokers and non-smokers diagnosed with MS, thus suggests an MS-associated lung T-cell phenotype, involvement of a specific T-cell response to smoke, and a genetic regulation of the macrophage response.

Expanded lung T-bet+RORγT+ CD4+ T-cells in sarcoidosis patients with a favourable disease phenotype.

Disease phenotypes of pulmonary sarcoidosis are distinguished by clinical rather than immunological criteria. We aimed to characterise patterns of CD4(+) T-cell lineage plasticity underlying the differences in clinical presentation and disease course between the acute form, Löfgren's syndrome, and the heterogeneous, potentially progressive "non-Löfgren" form.33 pulmonary sarcoidosis patients and nine controls underwent bronchoscopy with bronchoalveolar lavage. CD4(+) T-cell transcription factor, chemokine receptor and T-cell receptor expression, proliferation and cytokine production were assessed in the lavage fluid and peripheral blood using flow cytometry and multicolour FluoroSpot.CD4(+) T-cells simultaneously expressing the T-helper cell (Th)1 and Th17 transcriptional regulators T-bet and RORγT (T-bet(+)RORγT(+)) were identified in the lavage, but not blood, of all subjects, and to a significantly higher degree in Löfgren's patients. T-bet(+)RORγT(+) cells proliferated actively, produced interferon (IFN)γ and interleukin (IL)-17A, co-expressed the chemokine receptors CXCR3 and CCR6, and correlated with nonchronic disease. T-cell receptor-restricted Vα2.3(+)Vß22(+) T-cells strongly co-expressed T-bet/RORγT and CXCR3/CCR6. Cytokine production was more heterogeneous in Löfgren's patients, with significantly higher IL-17A, IL-10, IL-22 and IL-2, but lower IFNγ.Here we demonstrate the presence of lung T-bet(+)RORγT(+)CXCR3(+)CCR6(+) CD4(+) T-cells and Th17-associated cytokines especially in sarcoidosis patients with a favourable prognosis, suggesting a Th1/Th17-permissive environment in the lung with implications for disease resolution.

Sarcoidosis incidence and prevalence: a nationwide register-based assessment in Sweden.

Our objective was to estimate the contemporary incidence and prevalence of sarcoidosis using Swedish population-based register data.Adults with any sarcoidosis-coded visit were identified from the National Patient Register (hospitalisations 1964-2013 and outpatient care 2001-2013). Demographic and medication dispensing data were retrieved from national registers. We estimated the prevalence of sarcoidosis in 2013 overall and by county of residence. The incidence of sarcoidosis during 2003-2012 was estimated by sex, age, education level and year of diagnosis. Case definitions were varied to test their robustness.More than 16 000 individuals had a history of sarcoidosis in 2013. When defined as two or more sarcoidosis-coded visits, the prevalence was 160 per 100 000. Using different definitions, the prevalence ranged from 152 (requiring a specialist visit) to 215 per 100 000 (only one visit required). The highest prevalence was observed in northern less densely populated counties. The incidence was 11.5 per 100 000 per year and varied by -10% to +30% depending on case definition. The incidence peaked in males aged 30-50 years and in females aged 50-60 years, but did not differ by education level and was stable over time.This study represents the largest epidemiological investigation of sarcoidosis using population-based individual-level data. Age at diagnosis in men was 10 years younger than in women and geographical variation was observed.

History and Familial Aggregation of Immune-Mediated Diseases in Sarcoidosis: A Register-Based Case-Control Family Study.

BACKGROUND: An autoimmune component in the cause of sarcoidosis long has been debated, but population-based data on the clustering of immune-mediated diseases (IMDs) and sarcoidosis in individuals and families suggestive of shared cause is limited. RESEARCH QUESTION: Do patients with a history of IMDs have a higher risk of sarcoidosis and do IMDs cluster in families with sarcoidosis? STUDY DESIGN AND METHODS: We conducted a case-control family study (2001-2020). Patients with sarcoidosis (N = 14,146) were identified in the Swedish National Patient Register using a previously validated definition (≥ 2 International Classification of Diseases [ICD]-coded inpatient or outpatient visits). At diagnosis, patients were matched to up to 10 control participants from the general population (N = 118,478) for birth year, sex, and residential location. Patients, control participants, and their first-degree relatives (FDRs; Multi-Generation Register) were ascertained for IMDs by means of ICD codes in the Patient Register (1968-2020). Conditional logistic regression was used to estimate ORs and 95% CIs of sarcoidosis associated with a history of IMDs in patients and control participants and in FDRs. RESULTS: Patients with sarcoidosis exhibited a higher prevalence of IMDs compared with control participants (7.7% vs 4.7%), especially connective tissue diseases, cytopenia, and celiac disease. Familial aggregation was observed across IMDs; the strongest association was with celiac disease (OR, 2.09; 95% CI, 1.22-3.58), followed by cytopenia (OR, 1.88; 95% CI, 0.97-3.65), thyroiditis (OR, 1.72; 95% CI, 1.14-2.60), skin psoriasis (OR, 1.70; 95% CI, 1.34-2.15), inflammatory bowel disease (OR, 1.53; 95% CI, 1.14-2.03), immune-mediated arthritis (OR, 1.49; 95% CI, 1.20-1.85), and connective tissue disease (OR, 1.39; 95% CI, 1.00-1.93). INTERPRETATION: IMDs confer a higher risk of sarcoidosis and they aggregate in families with sarcoidosis, signaling a shared cause between IMDs and sarcoidosis. Our findings warrant further evaluation of shared genetic mechanisms.

Corrigendum: Sex differences in the genetics of sarcoidosis across European and African ancestry populations.

[This corrects the article DOI: 10.3389/fmed.2023.1132799.].