BackgroundThe aim of the current study was to estimate sex- and age-specific incidence rates of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) using population-based registry data. CFS/ME is a debilitating condition with large impact on patients and their families. The etiology is unknown, and the distribution of the disease in the general population has not been well described.MethodsCases of CFS/ME were identified in the Norwegian Patient Register (NPR) for the years 2008 to 2012. The NPR is nationwide and contains diagnoses assigned by specialist health care services (hospitals and outpatient clinics). We estimated sex- and age-specific incidence rates by dividing the number of new cases of CFS/ME in each category by the number of person years at risk. Incidence rate ratios were estimated by Poisson regression with sex, age categories, and year of diagnosis as covariates.ResultsA total of 5,809 patients were registered with CFS/ME during 2008 to 2012. The overall incidence rate was 25.8 per 100,000 person years (95% confidence interval (CI): 25.2 to 26.5). The female to male incidence rate ratio of CFS/ME was 3.2 (95% CI: 3.0 to 3.4). The incidence rate varied strongly with age for both sexes, with a first peak in the age group 10 to 19 years and a second peak in the age group 30 to 39 years.ConclusionsEarly etiological clues can sometimes be gained from examination of disease patterns. The strong female preponderance and the two age peaks suggest that sex- and age-specific factors may modulate the risk of CFS/ME.

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Background:Increased survival after cancer in young age has made long-term follow-up studies of high external validity important. In this national cohort study, we explored the impact of cancer in young age on reproduction and marital status in male survivors.Methods:Hazard ratios (HRs) and relative risks (RRs) of reproductive and marital outcomes were studied for male survivors of cancer in young age (<25 years) and cancer-free male comparisons, born during 1965–1985, by linking compulsory national registries in Norway.Results:Male cancer survivors (n=2687) had reduced paternity (HR: 0.72, 95% confidence interval (CI): 0.68–0.76). This was most apparent in survivors of testicular cancer, brain tumours, lymphoma, leukemia and bone tumours, and when diagnosed with cancer before 15 years of age. Male cancer survivors were more likely to avail of assisted reproduction (RR: 3.32, 95% CI: 2.68–4.11). There was no increased risk of perinatal death, congenital malformations, being small for gestational age, of low birth weight or preterm birth in their first offspring. Male cancer survivors were less likely to marry (HR: 0.93, 95% CI: 0.86–1.00), in particular brain tumour survivors.Conclusions:In this national cohort study, we demonstrated reduced paternity and increased use of assisted reproduction among male cancer survivors, but no adverse outcome for their first offspring at birth.

Suicide risk in adult cancer patients is found to be elevated, but limited information exists regarding risks of suicide and non-suicidal violent deaths when diagnosed with cancer in young age. We investigate suicide and violent deaths in a national cohort including individuals diagnosed with cancer before age 25. Through the linkage of different national registries (Cancer Registry of Norway, Norwegian Causes of Death Registry and the National Registry) a cohort of all live births in Norway during 1965-1985 was defined and followed up through 2008. Individuals diagnosed with cancer before age 25 and the cancer-free references were compared using an extended Cox proportional hazard regression model. The cohort comprised 1,218,013 individuals, including 5,440 diagnosed with cancer before age 25. We identified 24 suicides and 14 non-suicidal violent deaths in the cancer group. The hazard ratio (HR) of suicide in the cancer group was 2.5 (95% confidence interval (CI) 1.7-3.8), and was increased both when diagnosed with cancer in childhood (0-14 years of age); HR = 2.3 (95% CI: 1.2-4.6), and during adolescence/young adulthood (15-24 years); HR = 2.6 (95% CI: 1.5-4.2). Survivors of bone/soft tissue sarcomas, CNS tumors and testicular cancer were at particular risk. The risk of non-suicidal violent death was not increased in the cancer survivors (HR = 1.0; 95% CI: 0.6-1.7). Although based on small numbers and the absolute risk of suicide being low, these are novel findings with important implications for establishing adequate follow-up including suicide prevention strategies for young cancer survivors.

Previous studies on metabolic factors and bladder cancer (BC) risk have shown inconsistent results and have commonly not investigated associations separately by sex, smoking, and tumor invasiveness. Among 811,633 participants in six European cohorts, we investigated sex-specific associations between body mass index (BMI), mid-blood pressure (BP, [systolic + diastolic]/2), plasma glucose, triglycerides, total cholesterol and risk of BC overall, non-muscle invasive BC (NMIBC) and muscle invasive BC (MIBC). Among men, we additionally assessed additive interactions between metabolic factors and smoking on BC risk. During follow-up, 2,983 men and 754 women were diagnosed with BC. Among men, triglycerides and BP were positively associated with BC risk overall (hazard ratio [HR] per standard deviation [SD]: 1.17 [95% confidence interval (CI) 1.06-1.27] and 1.09 [1.02-1.17], respectively), and among women, BMI was inversely associated with risk (HR: 0.90 [0.82-0.99]). The associations for BMI and BP differed between men and women (p ≤ 0.005). Among men, BMI, cholesterol and triglycerides were positively associated with risk for NMIBC (HRs: 1.09 [95% CI 1.01-1.18], 1.14 [1.02-1.25], and 1.30 [1.12-1.48] respectively), and BP was positively associated with MIBC (HR: 1.23 [1.02-1.49]). Among women, glucose was positively associated with MIBC (HR: 1.99 [1.04-3.81]). Apart from cholesterol, HRs for metabolic factors did not significantly differ between MIBC and NMIBC, and there were no interactions between smoking and metabolic factors on BC. Our study supports an involvement of metabolic aberrations in BC risk. Whilst some associations were significant only in certain sub-groups, there were generally no significant differences in associations by smoking or tumor invasiveness.