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Abstract Background While individuals with normal gastrointestinal (GI) mucosa on endoscopy have a lower risk of colorectal cancer, risks of other cancers remain unexplored. Methods Through Sweden’s 28 pathology departments, we identified 415,092 individuals with a first GI biopsy with histologically normal mucosa during 1965–2016 and no prior cancer. These individuals were compared to 1,939,215 matched reference individuals from the general population. Follow-up began 6 months after biopsy, and incident cancer data were retrieved from the Swedish Cancer Register. Flexible parametric model was applied to estimate cumulative incidences and hazard ratios (HRs) for cancers. We also used full siblings (n = 441,534) as a secondary comparison group. Results During a median follow-up of 10.9 years, 40,935 individuals with normal mucosa (incidence rate: 82.74 per 10,000 person-years) and 177,350 reference individuals (incidence rate: 75.26) developed cancer. Restricting the data to individuals where follow-up revealed no cancer in the first 6 months, we still observed an increased risk of any cancer in those with a histologically normal mucosa (average HR = 1.07; 95%CI = 1.06–1.09). Although the HR for any and specific cancers decreased shortly after biopsy, we observed a long-term excess risk of any cancer, with an HR of 1.08 (95%CI = 1.05–1.12) and a cumulative incidence difference of 0.93% (95%CI = 0.61%-1.25%) at 30 years after biopsy. An elevated risk of gastric cancer, lung cancer, and hematological malignancy (including lymphoproliferative malignancy) was also observed at 20 or 30 years since biopsy. Sibling analyses confirmed the above findings. Conclusion Individuals with a histologically normal mucosa at biopsy and where follow-up revealed no cancer in the first 6 months, may still be at increased risk of cancer, although excess risks are small.

Abstract Background Studies on allergy-related diseases in relation to abdominal pain-related functional gastrointestinal disorders (AP-FGIDs) in children are few and results are contradictory. We examined the associations between childhood allergy-related diseases and adolescent AP-FGIDs in general and irritable bowel syndrome (IBS) in particular. Method Prospective population-based birth cohort study of 4089 children born in Sweden 1994-1996. We analysed data from 2949 children with complete follow-up at 16 years (y) and no diagnosis of inflammatory bowel disease or coeliac disease at 12y or 16y. Asthma, rhinitis, eczema, and food hypersensitivity (FH) were assessed through questionnaires at 1–2y, 4y, 8y, 12y, and 16y. AP-FGIDs and IBS were assessed through questionnaires at 16y and defined according to the Rome III criteria. Associations between childhood allergy-related diseases and any AP-FGID and IBS and 16y respectively were examined using binomial generalized linear models with a log link function and described as relative risk with 95% confidence intervals. Results The prevalence of any AP-FGID and IBS at 16y were 12.0% and 6.0% respectively. Eczema at 1–2y, 4y, and 8y, and FH at 12y and 16y were associated with an increased risk for any AP-FGID at 16y. Asthma and FH at 12y and 16y were associated with an increased risk for IBS at 16y. The relative risk for IBS at 16y increased with increasing number of concurrent allergy-related diseases at 16y, but linear trend for relative risk was only borderline statistically significant (P for trend = 0.05). Conclusions This prospective population-based study demonstrated positive associations between childhood allergy-related diseases and adolescent AP-FGIDs, including IBS, implicating shared pathophysiology among these disorders.

Abstract Background About 50% of patients with Crohn’s disease (CD) and about 20% of those with ulcerative colitis (UC) undergo surgery at some point during the course of the disease. The diagnostic validity of the Swedish National Patient Register (NPR) has previously been shown to be high for inflammatory bowel disease (IBD), but there are little data on the validity of IBD-related surgical procedure codes. Methods Using patient chart data as the gold standard, surgical procedure codes registered between 1966 and 2014 in the NPR were abstracted and validated in 262 randomly selected patients with a medical diagnosis of IBD. Of these, 53 patients had reliable data about IBD-related surgery. The positive predictive value (PPV), sensitivity and specificity of the surgical procedure codes were calculated. Results In total, 158 surgical procedure codes were registered in the NPR. One hundred fifty-five of these, representing 60 different procedure codes, were also present in the patient charts and validated using a standardized form. Of the validated codes 153/155 were concordant with the patient charts, corresponding to a PPV of 96.8% (95%CI = 93.9–99.1). Stratified in abdominal, perianal and other surgery, the corresponding PPVs were 94.1% (95%CI = 88.7–98.6), 100% (95%CI = 100–100) and 98.1% (95%CI = 93.1–100), respectively. Of 164 surgical procedure codes in the validated patient charts, 155 were registered in the NPR, corresponding to a sensitivity of the surgical procedure codes of 94.5% (95%CI = 89.6–99.3). The specificity of the NPR was 98.5% (95%CI = 97.6–100). Conclusions Data on IBD-related surgical procedure codes are reliable, with the Swedish National Patient Register showing a high sensitivity and specificity for such surgery.