Swedish Case-control Study Research Articles

Exposure to antibiotics and risk of latent autoimmune diabetes in adults and type 2 diabetes: results from a Swedish case-control study (ESTRID) and the Norwegian HUNT study.

Some studies find an increased risk of type 1 diabetes in children exposed to antibiotics. We investigated if exposure to antibiotics increases the risk of latent autoimmune diabetes in adults (LADA) and type 2 diabetes. We used data from a Swedish case-control study (Epidemiological Study of Risk Factors for LADA and Type 2 Diabetes [ESTRID]: LADA, n=597; type 2 diabetes, n=2065; control participants matched on participation time, n=2386) and a case-control study nested within the Norwegian Trøndelag Health Study (HUNT) (n=82/1279/2050). Anatomical Therapeutic Chemical (ATC) codes indicating antibiotic dispensations were retrieved from the Swedish National Prescribed Drug Register and Norwegian Prescription Database. Multivariable adjusted ORs with 95% CIs were estimated by conditional logistic regression and pooled using fixed-effects inverse-variance weighting. We observed no increased risk of LADA with exposure to antibiotics up to 1 year (ORpooled 1.15, 95% CI 0.93, 1.41) or 1-5 years (ORpooled 0.98, 95% CI 0.80, 1.20) prior to diagnosis/matching for one or more vs no dispensation of any type of antibiotic. An increased risk was observed for one or more vs no dispensations of narrow-spectrum antibiotics, but not broad-spectrum antibiotics, 6-10 years prior to LADA diagnosis (ORpooled 1.39, 95% CI 1.01, 1.91), which was driven by the Swedish data. There was little evidence of an increased risk of type 2 diabetes associated with antibiotic exposure 1-10 years prior to diagnosis. We found no evidence that exposure to broad-spectrum antibiotics up to 10 years prior to diagnosis increases the risk of LADA. There was some indication of increased LADA risk with exposure to narrow-spectrum antibiotics, which warrants further investigation.

Inflammatory plasma protein levels are elevated years before sarcoidosis diagnosis: a nested case-control study in Sweden.

Sarcoidosis is an immune-mediated inflammatory disease whose natural development is not well understood. We aimed to determine if inflammatory plasma protein levels are elevated before sarcoidosis diagnosis compared to controls. Furthermore, we investigated which proteins are increased and how long before diagnosis they are increased. Cases with sarcoidosis and controls matched 2:1 on sex, birthdate, subcohort and sample date were identified in the Northern Sweden Health and Disease Study to perform a nested case-control study. Cases were validated and included if they provided ≥1 plasma sample ≥2 years before sarcoidosis diagnosis. Plasma protein levels were measured using the Olink Inflammation panel and expressed in Normalized Protein eXpression values. Unconditional logistic regression models adjusted for age, sex, subcohort and time since sampling were used to estimate log odds ratios with 95% confidence intervals for each protein overall and by time to diagnosis. p-values were adjusted for multiple comparisons using the Benjamini-Hochberg method. We included 152 cases and 341 controls. Mean time between sample and sarcoidosis diagnosis was 13.4 years. Forty-four proteins were significantly elevated prior to sarcoidosis compared to controls in multivariable-adjusted analyses. The ten proteins with the lowest p-values were CCL3, CCL19, CDCP1, CXCL9, CXCL10, IFNγ, IL-12B, MCP-3, TNF, and TNFRSF9. Fewer proteins were associated with sarcoidosis in samples taken longer before diagnosis. Restricting to samples taken ≥10 years prior to sarcoidosis diagnosis, 27 proteins remained statistically significant. Several inflammatory proteins were elevated in plasma many years before sarcoidosis onset compared to controls, revealing a preclinical phase characterised by inflammation.

Pelvic inflammatory disease and risk of borderline ovarian tumors: A national population-based case-control study in Sweden.

The resemblance between fallopian tube cells and serous borderline ovarian tumors (BOTs) suggests a potential origin link, with salpingitis proposed as a contributing factor in the pathogenesis of BOT. This study aimed to explore the potential association between pelvic inflammatory disease (PID) and the risk of developing BOT. A national population-based case-control study in Sweden included women with BOT between 1999 and 2020 and 10 matched controls. Data from nationwide registers were analyzed using conditional logistic regression, adjusting for age, residential district, educational level and parity. Among 4782 cases and 45,167 controls, 2.0% of cases and 1.3% of controls had a history of PID. Previous PID was associated with an increased risk of BOT overall (aOR, 1.48; 95% CI, 1.19-1.85). Significant association was observed with serous tumors (aOR, 1.76; 95% CI, 1.36-2.29), while not with mucinous tumors (aOR, 0.95; 95% CI, 0.60-1.49). A dose-response relationship between number of PID episodes and serous BOT risk was noted (Ptrend < .001). This study demonstrates that PID is associated with increased risk of serous BOT, with a dose response relationship. The study highlights the potential serious implications of upper reproductive tract infections and inflammation. This underscores the need for further investigation of biological mechanisms and possible impact of PID on serous BOT development.

Inflammatory eye disease is a risk factor for future microscopic colitis: A nationwide population-based matched case control study.

Microscopic colitis (MC) is an inflammatory disorder of the colon. To date, the relationship between inflammatory eye diseases and MC is unclear. To assess whether inflammatory eye disease (iridocyclitis and episcleritis) is a risk factor for MC. We conducted a nationwide matched case control study in Sweden leveraging the ESPRESSO-study (a Swedish database containing data on all biopsies from the gastrointestinal tract from 1965 to 2017). In total, we identified 14,338 patients with biopsy-verified MC (diagnosed from 1981 to 2017). Patients with MC were matched (by age, sex, county and year of birth) with 68,753 controls from the general population and the occurrence of preceding inflammatory eye diseases (defined as diagnosis of episcleritis or iridocyclitis) in the two groups was compared. Multivariable adjusted odds ratios (aORs) were calculated using conditional logistic regression conditioned on the matching variables. A majority of patients with MC were women (71.9%) and the median age at MC diagnosis was 63.3years (interquartile range (IQR)=50.7-72.6). Some 225 (1.6%) MC patients had an earlier record of inflammatory eye disease compared with 614 (0.9%) in controls. These figures corresponded to an aOR of 1.77 (95% CI=1.52-2.07) for inflammatory eye diseases in patients with MC. Compared to siblings, the aOR for previous inflammatory eye diseases in MC was 1.52 (95% CI=1.17-1.98) and patients treated with budesonide, as a proxy for clinically significant disease, had a somewhat higher aOR for previous inflammatory eye diseases. Inflammatory eye diseases are more common in patients subsequently being diagnosed with MC. Our findings highlight that these conditions may have shared causes and inflammatory pathways and are of clinical interest to gastroenterologists, ophthalmologists and general practitioners.

Environmental risk factors for schizophrenia and bipolar disorder from childhood to diagnosis: a Swedish nested case-control study.

Shared genetic risk between schizophrenia (SCZ) and bipolar disorder (BD) is well-established, yet the extent to which they share environmental risk factors remains unclear. We compare the associations between environmental exposures during childhood/prior to disorder onset with the risk of developing SCZ and BD. We conducted a Swedish register-based nested case-control study using 4184 SCZ cases and 18 681 BD cases diagnosed 1988-2013. Cases were matched to five controls by birth year, birth region, and sex. Conditional logistic regression was used to estimate incidence rate ratios (IRR) for SCZ and BD for each exposure (severe childhood infections, adverse childhood experiences (ACEs), substance use disorders (SUDs), urban birth/longest residence). All SUD types were associated with very high risk (IRR 4.9-25.5), and all forms of ACEs with higher risk (IRR 1.5-4.3) for both disorders. In the mutually adjusted models, ACEs demonstrated slightly higher risk for BD (SCZ IRR 1.30, 1.19-1.42; BD IRR 1.49, 1.44-1.55), while for SUD, risk was higher for SCZ (SCZ IRR 9.43, 8.15-10.92; BD IRR 5.50, 5.15-5.88). Infections were associated with increased risk of BD (IRR 1.21, 1.17-1.26) but not SCZ. Urban birth and urban longest residence were associated with higher risk of SCZ (IRR 1.19, 1.03-1.37), while only the combination of urban birth and rural longest residence showed higher risk for BD (IRR 1.24, 1.13-1.35). There were both shared and unique environmental risk factors: SUDs and ACEs were risk factors for both disorders, while infections were more strongly associated with BD and urbanicity with SCZ.

Brain MRI microbleeds and risk of intracranial hemorrhage in atrial fibrillation patients: A Swedish case-control study

ObjectivesOur goal was to quantify the independent association of brain microbleeds with future intracranial hemorrhage (ICrH). Microbleed findings on brain magnetic resonance imaging (MRI) may identify distinctive risk factors for ICrH which could inform the anticoagulant therapy decision for atrial fibrillation (AF) patients. Our study design includes patients with MRIs for numerous reasons, not limited to evaluation of stroke. Materials and methodsThe source population was all patients with AF from a nationwide Swedish health care register. Case patients had an ICrH between 2006 and 2013 and ≥1 brain MRI for an unrelated condition before the ICrH. Each case was matched to four controls who had a brain MRI without a subsequent ICrH. The MRIs were re-reviewed by neuroradiologists. Associations between MRI findings and subsequent ICrH were assessed using logistic regression, adjusting for comorbidities and antithrombotic medications. ResultsA total of 78 cases and 312 matched controls were identified; 29 cases and 79 controls had MRI sequences suitable for analysis of microbleeds. Patients with ≥10 microbleeds had a markedly increased risk of ICrH (adjusted odds ratio 14.56; 95 % confidence interval: 2.86–74.16, p < 0.001). All patients with ≥10 microbleeds had microbleeds in the lobar region and ≥10 lobar microbleeds was associated with intracerebral hemorrhages, univariable OR 8.54 (2.01–36.33), p = 0.004. ConclusionsLeveraging a nationwide database with brain imaging obtained prior to ICrH, we identified a strong association between ≥10 microbleeds on brain MRI and subsequent ICrH among AF patients. Lobar brain regions were involved whenever there were ≥10 microbleeds. Brain MRIs may help optimize the anticoagulation decision in selected AF patients.

Does a prior diagnosis of infectious disease confer an increased risk of latent autoimmune diabetes in adults?

Infections are proposed risk factors for type 1 diabetes in children. We examined whether a diagnosis of infectious disease also confers an increased risk of latent autoimmune diabetes in adults (LADA). We used data from a population-based Swedish case-control study with incident cases of LADA (n=597) and matched controls (n=2386). The history of infectious disease was ascertained through national and regional patient registers. We estimated adjusted odds ratios (OR) with 95% confidence intervals for ≥1 respiratory (any/upper/lower), gastrointestinal, herpetic, other or any infectious disease episode, or separately, for 1 and ≥2 infectious disease episodes, within 0-1, 1-3, 3-5 and 5-10years before LADA diagnosis/matching. Stratified analyses were performed on the basis of HLA risk genotypes and Glutamic acid decarboxylase antibodies (GADA) levels. Individuals who developed LADA did not have a higher prevalence of infectious disease 1-10years before diabetes diagnosis. For example, OR was estimated at 0.87 (0.66, 1.14) for any versus no respiratory infectious disease within 1-3years. Similar results were seen for LADA with high-risk HLA genotypes (OR 0.95 [0.64, 1.42]) or high GADA levels (OR 1.10 [0.79, 1.55]), ≥2 episodes (OR 0.89 [0.56, 1.40]), and in infections treated using antibiotics (OR 1.03 [0.73, 1.45]). The only significant association was observed with lower respiratory disease the year preceding LADA diagnosis (OR 1.67 [1.06, 2.64]). Our findings do not support the idea that exposure to infections increases the risk of LADA. A higher prevalence of respiratory infection in the year before LADA diagnosis could reflect increased susceptibility to infections due to hyperglycemia.

Change in incidence of ischemic stroke and mortality among patients with atrial fibrillation over a period of 30 years, a nationwide, register-based cohort study

Abstract Background During the last decades we have faced large changes in lifestyle and cardiovascular risk factor patterns, as well as screening and treatment advances of patients with atrial fibrillation (AF). Aim To investigate trends in ischemic stroke (IS) and mortality in Sweden over a period of 30 years among patients with AF and compare it to matched controls without AF. Methods This is a Swedish nationwide registry-based retrospective case-control study of patients diagnosed with AF combining data from National Patient Register (NPR) and Cause of Death Register between 1987 and 2018. Controls were defined as Swedish inhabitants without AF and matched by age, sex and county. With the use of international classification of diseases (ICD) 9- and 10- codes we identified all patients diagnosed with AF, and comorbidities at baseline from NPR. Results In total, we identified 739,388 patients with AF and 1,386,448 matched controls. The mean age of the study population was 78.8 (12.6); and (46.2%) were female. Cochran-Armitage test showed a significant increase of all comorbidities over time, except for myocardial infarction for patients and PAH för controls. The Incidence rate for IS per 1000 person-year within one year declined from 40.9 (95% C.I.: 30.1-55.6) in 1987 to 16.2 (95% C.I.: 9.9-26.4) in 2017 (p &amp;lt;.0001) for patients with AF and from 12.2 (95% CI: 7.0-21.4) in 1987 to 6.2 (95% CI: 2.8-13.7) in 2017 (p &amp;lt;.0001) in controls. The prescription of oral anticoagulant therapy (OAK) increased from 40% in 2006 to almost 80% in 2018. The total 1-year mortality rate of IS was at 175.4 (151.3-203.4) for AF cases and 58.3 (45.1-75.4) for controls (p&amp;lt;0001). Compared to controls and adjusted for age, sex and comorbidities patients had HR for IS at 3.01 (95% CI: 2.89-3.13) between 1987 and 1999 that decreased to HR 2.75 (95% CI: 2.63-2.88) between 2010 and 2017 in patients with AF. After adjustment for baseline comorbidities and OAK the one-year risk for IS decreased from HR 1.01 (95% CI: 0.95-1.08) in 2012 to 0.41 (95% CI: 0.36-0.47) in patients and HR 0.50 (95% CI: 0.43-0.58) in 2012 to 0.37 (95% CI: 0.31-0.43) in controls, respectively (both p&amp;lt;0.0001). Conclusions This study revealed significant prognostic improvement of patients with AF showing decrease in the incidence rate and relative risk for IS, as well as all-cause mortality within one year of AF diagnose. The prescription of OACs almost doubled between 2006 and 2018 in patients with AF and was associated with a significant decrease of the relative risk for IS to almost same level as in controls without AF.

Type, Etiology, and Duration of Epilepsy as Risk Factors for SUDEP: Further Analyses of a Population-Based Case-Control Study.

We conducted a nationwide case-control study in Sweden to investigate the risk of sudden unexpected death in epilepsy (SUDEP) in relation to epilepsy duration, epilepsy type, and etiology in combination with occurrence and frequency of tonic-clonic seizures (TCS) and nocturnal TCS. The study comprised 255 SUDEP cases and 1,148 epilepsy controls. Clinical information was obtained from medical records. The association between SUDEP and risk factors was estimated by odds ratios (ORs) with 95% CIs calculated by conditional logistic regression to account for matching by sex and calendar time. The risk of SUDEP was elevated in people with focal (OR 1.48, 95% CI 1.00-2.20), generalized and focal (OR 3.51, 95% CI 1.55-7.96), or unknown (OR 2.43, 95% CI 1.29-4.57) vs generalized epilepsy type. Increased risk of SUDEP was also observed in relation to epilepsy with traumatic causes (OR 2.27, 95% CI 1.33-3.89 vs genetic etiology) or short duration (OR 1.71, 95% CI 1.01-2.87 for 0-5 vs 6-15 years duration). Among those with 1-3 TCS during the preceding year, structural epilepsy etiology was associated with a more than 10-fold increase 10.84 (4.85-24.27) in SUDEP risk compared with people with genetic epilepsy without TCS. The risk with ≥4 TCS the preceding year was similar among those with generalized and focal epilepsies. Those with ≥4 TCS had an OR of 210.73 (95% CI 28.40-∞) during years 0-5 compared with those free from TCS and an epilepsy duration of 6-15 years. The combination of short epilepsy duration (0-5 years) and nocturnal TCS conferred an OR of 45.99 (95% CI 12.19-173.61) compared with having longer duration (6-15 years) and being free from nocturnal TCS. Although certain etiologies, such as post-traumatic epilepsy, seem to entail a higher SUDEP risk, our data indicate that frequent and nocturnal TCS carry a similar level of risk whether focal or generalized from onset. The tonic-clonic part of the seizure seems to be decisive for the fatal outcome. SUDEP risk associated with TCS is highest during the first years after the epilepsy diagnosis which calls for effective TCS treatment and vigilance from the onset of diagnosis.

Pelvic inflammatory disease and risk of epithelial ovarian cancer: a national population-based case-control study in Sweden

Epithelial ovarian cancer is an insidious disease, and women are often diagnosed when the disease is beyond curative treatment. Accordingly, identifying modifiable risk factors is of paramount importance. Inflammation predisposes an individual to cancer in various organs, but whether pelvic inflammatory disease is associated with an increased risk of epithelial ovarian cancer has not been fully determined. This study aimed to investigate a possible association between clinically verified pelvic inflammatory disease and the risk of epithelial ovarian cancer. In this national population-based case-control study, all women in Sweden diagnosed with epithelial ovarian cancer between 1999 and 2020 and 10 controls for each were identified, matched for age and residential district. Using several Swedish nationwide registers, data on previous pelvic inflammatory disease and potential confounding factors (age, parity, educational level, and previous gynecologic surgery) were retrieved. Adjusted odds ratios and 95% confidence intervals were estimated using conditional logistic regression. Histotype-specific analyses were performed for the subgroup of women diagnosed with epithelial ovarian cancer between 2015 and 2020. Moreover, hormonal contraceptives and menopausal hormone therapy were adjusted in addition to the aforementioned confounders. This study included 15,072 women with epithelial ovarian cancer and 141,322 controls. Most women (9102 [60.4%]) had serous carcinoma. In a subgroup of cases diagnosed between 2015 and 2020, high-grade serous carcinoma (2319 [60.0%]) was identified. A total of 168 cases (1.1%) and 1270 controls (0.9%) were diagnosed with pelvic inflammatory disease. Previous pelvic inflammatory disease was associated with an increased risk of epithelial ovarian cancer (adjusted odds ratio, 1.39; 95% confidence interval, 1.17-1.66) and serous carcinoma (adjusted odds ratio, 1.46; 95% confidence interval, 1.18-1.80) for the entire study population. For the subgroup of women diagnosed in 2015-2020, pelvic inflammatory disease was associated with high-grade serous carcinoma (adjusted odds ratio, 1.43; 95% confidence interval, 1.01-2.04). The odds ratios of the other histotypes were as follows: endometrioid (adjusted odds ratio, 0.13; 95% confidence interval, 0.02-1.06), mucinous (adjusted odds ratio, 1.55; 95% confidence interval, 0.56-4.29), and clear cell carcinoma (adjusted odds ratio, 2.30; 95% confidence interval, 0.90-5.86). A dose-response relationship was observed between the number of pelvic inflammatory disease episodes and the risk of epithelial ovarian cancer (Ptrend<.001). A history of pelvic inflammatory disease is associated with an increased risk of epithelial ovarian cancer and a dose-response relationship is evident. Histotype-specific analyses show an association with increased risk of serous epithelial ovarian cancer and high-grade serous carcinoma and potentially also with clear cell carcinoma, but there is no significant association with other histotypes. Infection and inflammation of the upper reproductive tract might have serious long-term consequences, including epithelial ovarian cancer.

Occupational risks associated with severe COVID-19 disease and SARS-CoV-2 infection - a Swedish national case-control study conducted from October 2020 to December 2021.

This study aimed to investigate whether workplace factors and occupations are associated with SARS-CoV-2 infection or severe COVID-19 in the later waves of the pandemic. We studied 552 562 cases with a positive test for SARS-CoV-2 in the Swedish registry of communicable diseases, and 5985 cases with severe COVID-19 based on hospital admissions from October 2020 to December 2021. Four population controls were assigned the index dates of their corresponding cases. We linked job histories to job-exposure matrices to assess the odds for different transmission dimensions and different occupations. We used adjusted conditional logistic analyses to estimate odds ratios (OR) for severe COVID-19 and SARS-CoV-2 with 95% confidence intervals (CI). The highest OR for severe COVID-19 were for: regular contact with infected patients, (OR 1.37, 95% CI 1.23-1.54), close physical proximity (OR 1.47, 95% CI 1.34-1.61), and high exposure to diseases or infections (OR 1.72, 95% CI 1.52-1.96). Mostly working outside had lower OR (OR 0.77, 95% CI 0.57-1.06). The odds for SARS-CoV-2 when mostly working outside were similar (OR 0.83, 95% CI 0.80-0.86). The occupation with the highest OR for severe COVID-19 (compared with low-exposure occupations) was certified specialist physician (OR 2.05, 95% CI 1.31-3.21) among women and bus and tram drivers (OR 2.04, 95% CI 1.49-2.79) among men. Contact with infected patients, close proximity and crowded workplaces increase the risks for severe COVID-19 and SARS-CoV-2 infection. Outdoor work is associated with decreased odds for SARS-CoV-2 infection and severe COVID-19.

Serum levels of soluble urokinase plasminogen activator receptor in juvenile idiopathic arthritis: a single-center Swedish case-control study

ObjectivesReliable biomarkers in the early stages of idiopathic arthritis (JIA) are scarce and the disease heterogeneity makes it clinically challenging to predict the risk of joint damage. Biomarkers with prognostic potential are warranted in order to individualize treatment and follow-up in JIA. The soluble urokinase plasminogen activator receptor (suPAR) has been reported as an easily measurable biomarker for prognosis and severity in several rheumatic diseases but it has never been studied in JIA.MethodsSera from 51 well-characterized patients with JIA and 50 age- and sex-matched control subjects were collected and stored for later analysis of suPAR. Patients were carefully followed clinically over 3 years and analysis of erythrocyte sedimentation rate, C-reactive protein, rheumatoid factor (RF) and antibodies against cyclic citrullinated peptides (anti-CCP) were analyzed as part of clinical routine. Signs of joint erosions were evaluated by radiography.ResultsOverall, the levels of suPAR did not differ significantly between JIA patients and controls but those with polyarticular involvement showed higher suPAR (p = 0.013). In addition, elevated suPAR were associated with joint erosions (p = 0.026). Two RF/anti-CCP negative individuals with erosions showed high levels of suPAR.ConclusionsWe present new data on the biomarker suPAR in JIA. Our results indicate that, apart from RF and anti-CCP, analysis of suPAR could be of additional value in assessing the risk of erosions. Analysis of suPAR early could potentially guide treatment decision-making in JIA, but our observations should be confirmed in prospective studies.

Predominant Antibody Deficiency and Risk of Microscopic Colitis: A Nationwide Case-Control Study in Sweden

ObjectivePredominant antibody deficiency (PAD) disorders, including common variable immunodeficiency (CVID), have been linked to increased risk of gastrointestinal infections and inflammatory bowel diseases. However, there are limited data on the relationship between predominant antibody deficiency disorders, specifically CVID, and the risk of microscopic colitis (MC). DesignWe performed a nationwide case-control study of Swedish adults with MC diagnosed between 1997 and 2017 (n = 13,651). Data on biopsyverified MC were retrieved from Sweden's all 28-pathology departments through the Epidemiology Strengthened by histoPathology Reports in Sweden (ESPRESSO) study. We defined predominant antibody deficiency using International Union of Immunologic Societies (IUIS) phenotypic classification. Individuals with MC were matched to population controls by age, sex, calendar year, and county. We used logistic regression to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). ResultsThe prevalence of PAD in MC was 0.4% as compared to 0.05% in controls. After adjustment for potential confounders, this corresponded to an aOR of 7.29 (95%CI 4.64–11.63). The association was higher for CVID (aOR 21.01, 95% 5.48–137.44) compared to other antibody deficiencies (aOR 6.16, 95% CI 3.79–10.14). In exploratory analyses, the association between PAD and MC was particularly strong among males (aOR 31.73, 95% CI 10.82–135.04). ConclusionIn this population-based study, predominant antibody deficiency was associated with risk of MC, particularly among males. Clinicians who encounter these patients should consider a detailed infectious history and screening for antibody deficiency.

Evaluation of Birth by Cesarean Delivery and Development of Early-Onset Colorectal Cancer

The incidence of early-onset colorectal cancer (CRC), diagnosed younger than 50 years of age, has increased worldwide. Gut dysbiosis throughout the life course is hypothesized as a leading mechanism, yet epidemiologic data are limited. To prospectively examine the association between birth by cesarean delivery and early-onset CRC among offspring. In this population-based, nationwide case-control study in Sweden, adults diagnosed with CRC between 18 and 49 years of age from 1991 to 2017 were identified through the Epidemiology Strengthened by Histopathology Reports in Sweden (ESPRESSO) cohort. Up to 5 general population control individuals without CRC were matched with each case on age, sex, calendar year, and county of residence. Pathology-confirmed end points were linked with the Swedish Medical Birth Register and other national registers. Analyses were conducted from March 2022 through March 2023. Birth by cesarean delivery. The primary outcome was development of early-onset CRC in the overall population and by sex. We identified 564 case patients with incident early-onset CRC (mean [SD] age, 32.9 [6.2] years; 284 [50.4%] male) and 2180 matched controls (mean [SD] age, 32.7 [6.3] years; 1104 [50.6%] male). Compared with vaginal delivery, birth by cesarean delivery was not associated with early-onset CRC in the overall population (adjusted odds ratio [aOR], 1.28; 95% CI, 0.91-1.79) after multivariable adjustment for matching and maternal and pregnancy-related factors. A positive association was found for females (aOR, 1.62; 95% CI, 1.01-2.60), but there was no association for males (aOR, 1.05; 95% CI, 0.64-1.72). In this nationwide, population-based case-control study, birth by cesarean delivery was not associated with early-onset CRC compared with birth by vaginal delivery in the overall population in Sweden. However, females born by cesarean delivery had greater odds of early-onset CRC compared with individuals born through vaginal delivery. This finding suggests that early-life gut dysbiosis may contribute to early-onset CRC in females.

Previous pre-eclampsia, gestational diabetes mellitus and the risk of cardiovascular disease: A nested case-control study in Sweden.

Pre-eclampsia and gestational diabetes mellitus (GDM) are two common pregnancy complications that affect birth outcomes and are associated with a long-term risk of cardiovascular disease (CVD). The aims of this study were to investigate if the pre-eclampsia association with CVD is independent of GDM and modified by body mass index (BMI) or GDM. Case-control study. Sweden. Cases were women with a first CVD event between 1991 and 2008 and a previous pregnancy who were matched with controls without CVD (1:5) by year of birth, age and region of birth. Conditional logistic regression was used to evaluate the associations of GDM, pre-eclampsia and maternal BMI with CVD adjusted for potential confounders and effect modifications with interaction tests. CVD. There were 2639 cases and 13 310 controls with complete data. Pre-eclampsia and GDM were independent risk factors for CVD (adjusted odds ratio [aOR] 2.59, 95% CI 2.12-3.17 and aOR 1.47, 95% CI 1.04-2.09, respectively). After stratifying by maternal BMI, the adjusted association of pre-eclampsia with CVD did not differ notably between BMI groups: normal weight (aOR 2.65, 95% CI 1.90-3.69), overweight (aOR 2.67, 95% CI 1.52-4.68) and obesity (aOR 3.03, 95% CI 0.74-12.4). Similar findings were seen when stratifying on GDM/non-GDM. Pre-eclampsia and GDM are independent risk factors for later CVD and having both during pregnancy is a major risk factor for later CVD. The association between pre-eclampsia and CVD is not modified by BMI. Effective CVD preventive programs for high-risk women are urgently needed in order to improve women's long-term health.

Type 1 diabetes and microscopic colitis: A nationwide matched case-control study in Sweden.

Microscopic colitis (MC) is a colonic inflammatory condition associated with autoimmune dysfunction. Type 1 diabetes (T1D) is a chronic disease induced by autoimmune destruction of pancreatic β-cells. We aimed to examine the association between T1D and MC. A matched case-control study was conducted using the nationwide ESPRESSO cohort as study base. All biopsy-confirmed MC patients born after 1940 were identified and compared to biopsy-free individuals matched from the general population for T1D diagnosis using the Swedish National Patient Register. The T1D-MC association was estimated as odds ratios (ORs) and 95% confidence intervals (CIs) by conditional logistic models, considering differences by sex and MC subtype. Full sibling comparison and adjustment for MC-associated medications were also performed. We identified 352 (3.7%) and 945 (2.0%) T1D diagnoses from 9,600 MC cases and 47,870 matched population controls, respectively, which corresponded to an overall OR of 1.79 (95% CI: 1.56-2.05). The association was stronger for collagenous colitis (OR, 2.15; 95% CI: 1.70-2.71) than lymphocytic colitis (OR, 1.62; 95% CI: 1.37-1.92) and remained statistically significant in full sibling comparison (OR, 1.46; 95%: 1.18-1.81). Medication adjustment attenuated the association to null among females (OR: 1.02; 95% CI: 0.82-1.27) but not among males (OR: 1.45; 95% CI: 1.11-1.90). T1D diagnosis was almost 80% more prevalent in MC patients compared to general population. This positive association did not seem to be spurious due to residual confounding shared by full siblings but may relate to consumption of medications associated with MC onset.

Exposure to phenoxyacetic acids and glyphosate as risk factors for non-Hodgkin lymphoma– pooled analysis of three Swedish case-control studies including the sub-type hairy cell leukemia

The association between pesticide exposure and non-Hodgkin lymphoma (NHL) including hairy cell leukemia (HCL) was analyzed in a pooled study of three case-control studies. Results on exposure to pesticides were based on 1,425 cases and 2,157 controls participating in the studies. Exposures were assessed by self-administered questionnaires completed as needed by phone. In the pooled univariate analyses adjusted by age, gender and year of diagnosis, exposure to herbicides of the phenoxyacetic acid type yielded statistically significant increased risk with odds ratio (OR) = 1.9, 95% confidence interval CI) = 1.4–2.5. The herbicide glyphosate gave OR = 2.2, 95% CI = 1.3–3.8. Impregnating agents increased the risk. No clear dose-response effect was seen. OR was highest in the >10–20 years latency group for herbicides and impregnating agents. In the multivariate analysis including main pesticide groups, statistically significant increased risk was found for herbicides, OR = 1.6, 95% CI = 1.2–2.1 and impregnating agents with OR = 1.4, 95% CI = 1.1–1.8. This analysis confirmed an association between NHL including HCL and exposure to certain herbicides.

The Risk of Cholesteatoma in Individuals With First-degree Relatives Surgically Treated for the Disease

Cholesteatoma in the middle ear is not regarded as a hereditary disease, but case reports of familial clustering exist in the literature, as well as observed familial cases in the clinical work. However, the knowledge regarding cholesteatoma as a hereditary disease is lacking in the literature. To assess the risk of cholesteatoma in individuals with a first-degree relative surgically treated for the same disease. In this nested case-control study in the Swedish population between 1987 and 2018 of first-time cholesteatoma surgery identified from the Swedish National Patient Register, 2 controls per case were randomly selected from the population register through incidence density sampling, and all first-degree relatives for cases and controls were identified. Data were received in April 2022, and analyses were conducted between April and September 2022. Cholesteatoma surgery in a first-degree relative. The main outcome was first-time cholesteatoma surgery. The association between having a first-degree relative with cholesteatoma and the risk of cholesteatoma surgery in the index persons was estimated by odds ratios (ORs) and 95% CIs through conditional logistic regression analysis. Between 1987 and 2018, 10 618 individuals with a first-time cholesteatoma surgery (mean [SD] age at surgery, 35.6 [21.5] years; 6302 [59.4%] men) were identified in the Swedish National Patient Register. The risk of having a cholesteatoma surgery was almost 4 times higher in individuals having a first-degree relative surgically treated for the disease (OR, 3.9; 95% CI, 3.1-4.8), but few cases were exposed overall. Among the 10 105 cases with at least 1 control included in the main analysis, 227 (2.2%) had at least 1 first-degree relative treated for cholesteatoma, while the corresponding numbers for controls were 118 of 19 553 control patients (0.6%). The association was stronger for individuals under the age of 20 years at first surgery (OR, 5.2; 95% CI, 3.6-7.6) and for a surgery involving the atticus and/or mastoid region (OR, 4.8; 95% CI, 3.4-6.2). There was no difference in the prevalence of having a partner with cholesteatoma between cases and controls (10 cases [0.3%] and 16 controls [0.3%]; OR, 0.92; 95% CI, 0.41-2.05), which implies that increased awareness does not explain the association. In this Swedish case-control study using nationwide register data with high coverage and completeness, the findings suggest that the risk of cholesteatoma in the middle ear is strongly associated with a family history of the condition. Family history was nevertheless quite rare and can therefore only explain a limited number of all cases; these families could be an important source for information regarding the genetic background for cholesteatoma disease.

Incidence of LADA and Type 2 Diabetes in Relation to Tobacco Use and Genetic Susceptibility to Type 2 Diabetes and Related Traits: Findings From a Swedish Case-Control Study and the Norwegian HUNT Study.

Smoking and Swedish smokeless tobacco (snus) are associated with latent autoimmune diabetes in adults (LADA) and type 2 diabetes (T2D). Our aim was to investigate whether genetic susceptibility to T2D, insulin resistance (IR), and insulin secretion (IS) aggravate these associations. We used data from two population-based Scandinavian studies with case subjects with LADA (n = 839) and T2D (n = 5,771), matched control subjects (n = 3,068), and 1,696,503 person-years at risk. Pooled, multivariate relative risks (RR) with 95% CI were estimated for smoking/genetic risk scores (T2D-GRS, IS-GRS, and IR-GRS), and ORs for snus or tobacco/GRS (case-control data). We estimated additive (proportion attributable to interaction [AP]) and multiplicative interaction between tobacco use and GRS. The RR of LADA was elevated in high IR-GRS heavy smokers (≥15 pack-years; RR 2.01 [CI 1.30, 3.10]) and tobacco users (≥15 box/pack-years; RR 2.59 [CI 1.54, 4.35]) compared with low IR-GRS individuals without heavy use, with evidence of additive (AP 0.67 [CI 0.46, 0.89]; AP 0.52 [CI 0.21, 0.83]) and multiplicative (p = 0.003; p = 0.034) interaction. In heavy users, there was additive interaction between T2D-GRS and smoking, snus, and total tobacco use. The excess risk conferred by tobacco use did not differ across GRS categories in T2D. Tobacco use may confer a higher risk of LADA in individuals with genetic susceptibility to T2D and insulin resistance, whereas genetic susceptibility does not seem to influence the increased T2D incidence associated with tobacco use.

Association of inflammatory bowel disease in first-degree relatives with risk of colorectal cancer: A nationwide case-control study in Sweden.

This study aims to assess the association between inflammatory bowel disease (IBD) history in first-degree relatives (FDRs) and colorectal cancer (CRC) risk. We conducted a nationwide case-control study in Sweden among 69 659 CRC cases and 343 032 non-CRC controls matched on age, sex, birth year and residence county. Through linkage of multi-generation register and the nationwide ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) cohort, we ascertained IBD diagnoses among parents, full siblings and offspring of the index individuals. Odds ratios (ORs) of CRC associated with IBD family history were calculated using conditional logistic regression. 2.2% of both CRC cases (1566/69659) and controls (7676/343027) had ≥1 FDR with IBD history. After adjusting for family history of CRC, we observed no increased risk of CRC in FDRs of IBD patients (OR, 0.96; 95%CI, 0.91-1.02). The null association was consistent according to IBD subtype (Crohn's disease or ulcerative colitis), number of FDRs with IBD (1 or ≥ 2), age at first IBD diagnosis in FDRs (<18, 18-39, 40-59 or ≥60 years), maximum location/extent of IBD or FDR relation (parent, sibling or offspring). The null association remained for early-onset CRC (diagnosed at age <50 years). In conclusion, IBD history in FDRs was not associated with an increased risk of CRC. Our findings suggest that extra screening for CRC may not be needed in the offspring, siblings or parents of IBD patients, and strengthen the theory that it is the actual inflammation or atypia of the colon in IBD patients that confers the increased CRC risk.