Background Prevalence of migraine is high during the reproductive age. Although migraine often improves during pregnancy, the risk of adverse pregnancy, birth, neonatal, and neurological outcomes in mother and offspring remains poorly understood. Objective To investigate the associations between maternal migraine and risks of adverse pregnancy outcomes in the mother, and birth, neonatal and postnatal outcomes in the offspring. Methods We used Danish population registries to assemble a cohort of pregnancies among women with migraine and an age‐ and conception year‐matched comparison cohort of pregnancies among women without migraine. The study period was 2005‐2012. We computed adjusted prevalence ratios (aPRs) for pregnancy and birth outcomes and adjusted risk ratios (aRRs) for neonatal and postnatal outcomes, adjusting for age, preconception medical history, and preconception reproductive history. Results We identified 22,841 pregnancies among women with migraine and 228,324 matched pregnancies among women without migraine. Migraine was associated with an increased risk of pregnancy‐associated hypertension disorders (aPR: 1.50 [95% confidence interval (CI): 1.39‐1.61]) and miscarriage (aPR: 1.10 [95% CI: 1.05‐1.15]). Migraine was associated with an increased prevalence of low birth weight (aPR: 1.14 [95% CI: 1.06‐1.23]), preterm birth (aPR: 1.21 [95% CI: 1.13‐1.30]) and cesarean delivery (aPR: 1.20 [95% CI: 1.15‐1.25]), but not of small for gestational age offspring (aPR: 0.94 [95% CI: 0.88‐0.99]) and birth defects (aPR: 1.01 [95% CI: 0.93‐1.09]). Offspring prenatally exposed to maternal migraine had elevated risks of several outcomes in the neonatal and postnatal period, including intensive care unit admission (aRR: 1.22 [95% CI: 1.03‐1.45]), hospitalization (aRR: 1.12 [95% CI: 1.06‐1.18]), dispensed prescriptions (aRR: 1.34 [95% CI: 1.24‐1.45]), respiratory distress syndrome (aRR: 1.20 [95% CI: 1.02‐1.42]), and febrile seizures (aRR: 1.27 [95% CI: 1.03‐1.57), but not of death (aRR: 0.67 [95% CI: 0.43‐1.04]) and cerebral palsy (aRR: 1.00 [95% CI: 0.51‐1.94]). Conclusions Women with migraine and their offspring have greater risks of several adverse pregnancy outcomes than women without migraine.

Background and Objectives:To examine risks of stroke recurrence and mortality after first and recurrent stroke.Methods:Using Danish nationwide health registries, we included patients (age ≥18 years) with first-time ischemic stroke (N = 105,397) or intracerebral hemorrhage (N = 13,350) during 2004–2018. Accounting for the competing risk of death, absolute risks of stroke recurrence were computed separately for each stroke subtype and within strata of age groups, sex, stroke severity, body mass index, smoking, alcohol, the Essen stroke risk score, and atrial fibrillation. Mortality risks were computed after first and recurrent stroke.Results:After adjusting for competing risks, the overall 1-year and 10-year risks of recurrence were 4% and 13% following first-time ischemic stroke and 3% and 12% following first-time intracerebral hemorrhage. For ischemic stroke, the risk of recurrence increased with age, was higher for men and following mild than more severe stroke. The most marked differences were across Essen risk scores, for which recurrence risks increased with increasing scores. For intracerebral hemorrhage, risks were similar for both sexes and did not increase with Essen risk score. For ischemic stroke, the 1-year and 10-year risks of all-cause mortality were 17% and 56% after a first-time stroke and 25% and 70% after a recurrent stroke; corresponding estimates for intracerebral hemorrhage were 37% and 70% after a first-time event and 31% and 75% after a recurrent event.Conclusion:The risk of stroke recurrence was substantial following both subtypes, but risks differed markedly among patient subgroups. The risk of mortality was higher after a recurrent than first-time stroke.

ObjectiveTo investigate the extent to which the incidence and mortality of a first-time stroke among younger and older adults changed from 2005 to 2018 in Denmark using nationwide registries.MethodsWe used the Danish Stroke Registry and the Danish National Patient Registry to identify patients 18 to 49 years of age (younger adults) and those ≥50 years of age (older adults) with a first-time ischemic stroke, intracerebral hemorrhage, or subarachnoid hemorrhage. We computed age-standardized incidence rates and 30-day and 1-year mortality risks separately for younger and older adults and according to smaller age groups, stroke subtype, sex, and severity (Scandinavian Stroke Scale score). Average annual percentage changes (AAPCs) were computed to assess temporal trends.ResultsWe identified 8,680 younger adults and 105,240 older adults with an ischemic stroke or intracerebral hemorrhage. The incidence rate per 100,000 person-years of ischemic stroke (20.8 in 2005 and 21.9 in 2018, AAPC −0.6 [95% confidence interval (CI) −1.5 to 0.3]) and intracerebral hemorrhage (2.2 in 2005 and 2.5 in 2018, AAPC 0.6 [95% CI −1.0 to 2.3]) remained steady in younger adults. In older adults, rates of ischemic stroke and intracerebral hemorrhage declined, particularly in those ≥70 years of age. Rates of subarachnoid hemorrhage declined, but more so in younger than older adults. Stroke mortality declined over time in both age groups, attributable largely to declines in the mortality after severe strokes. Most trends were similar for men and women.ConclusionThe incidence of ischemic stroke and intracerebral hemorrhage was steady in younger adults from 2005 to 2018, while it dropped in adults >70 years of age. Stroke mortality declined during this time.

We found no substantial seasonality for MI, ischemic stroke, or hemorrhagic stroke occurrence during 1977-2016. Modest peak-to-trough ratios should be interpreted after considering bias induced by random variation.

Background: Accurate estimates of risks of poststroke outcomes from large population–based studies can provide a basis for public health policy decisions. We examined the absolute and relative risks of a spectrum of incident mental disorders following ischemic stroke and intracerebral hemorrhage. Methods: During 2004 to 2018, we used Danish registries to identify patients (≥18 years and with no hospital history of mental disorders), with a first-time ischemic stroke (n=76767) or intracerebral hemorrhage (n=9344), as well as age-,sex-, and calendar year–matched general population (n=464 840) and myocardial infarction (n=92 968) comparators. We computed risk differences, considering death a competing event, and hazard ratios adjusted for income, occupation, education, and history of cardiovascular and noncardiovascular comorbidity. Results: Compared with the general population, following ischemic stroke, the 1-year risk difference was 7.3% (95% CI, 7.0–7.5) for mood disorders (driven by depression), 1.4% (95% CI, 1.3–1.5) for organic brain disorders (driven by dementia and delirium), 0.8% (95% CI, 0.7–0.8) for substance abuse disorders (driven by alcohol and tobacco abuse), and 0.5% (95% CI, 0.4–0.5) for neurotic disorders (driven by anxiety and stress disorders). For suicide, risk differences were near null. Hazard ratios were particularly elevated in the first year of follow-up, ranging from a 2- to a 4-fold increased hazard, decreasing thereafter. Compared with myocardial infarction patients, the 1-year risk difference was 4.9% (95% CI, 4.6 to 5.3) for mood disorders, 1.0% (95% CI, 0.8 to 1.1) for organic brain disorders, 0.1% (95% CI, 0.0 to 0.2) for substance abuse disorders, but −0.2% (95% CI, −0.2 to −0.1) for neurotic disorders. Hazard ratios during the first year of follow-up were elevated 1.1- to 1.8-fold for mood, organic brain, and neurotic disorders, while decreased 0.8-fold for neurotic disorders. Conclusions: The considerably greater risks of mental disorders following a stroke, particularly mood disorders, underline the importance of mental health evaluation after stroke.

Objective:The purpose of this study was to examine overall and site-specific cancer risk among individuals diagnosed with migraine compared with the general population.Background: Current evidence regarding migraine and risk of cancer is sparse and inconclusive.Methods: We conducted a nationwide population-based cohort study with data collected routinely and prospectively from Danish population-based registries from 1995 to 2017.We computed the age-and sex-standardized incidence ratio (SIR) as the ratio of observed to expected cancers among patients diagnosed with migraine in the study population overall, and by encounter type of first diagnosis (inpatient, outpatient specialty clinic, and emergency department). Site-specific cancers were grouped according to etiology. Results:We identified 72,826 patients with a first-time hospital migraine diagnosis. There were 3090 observed overall cancer cases among individuals diagnosed with migraine as compared with 3108 expected cases (SIR 0.99, 95% confidence interval[CI]: 0.96-1.03). The cumulative incidence of all cancers combined from 1995 to 2017 among those with a first-time migraine diagnosis was 9.47% (95% CI: 9.08-9.87). The SIRs for most cancers were consistent with absence of an association: 1.00 (95% CI: 0.94-1.06) for hormone-related cancers, 0.96 (95% CI: 0.88-1.03) for smoking-related cancers, 1.10 (95% CI: 0.98-1.24) for hematologic cancers, and 0.95 (95% CI: 0.85-1.06) for immune-related cancers. Exceptions were SIRs for gastrointestinal cancers (0.78, 95% CI: 0.70-0.87) and for cancers of neurological origin (1.57, 95% CI: 1.40-1.76). Conclusions:For most cancer groups, our results did not support an association with migraine. The exceptions were an increased risk for cancers of neurological origin and a decreased risk for gastrointestinal cancers. These findings may reflect a true difference in risk among individuals with migraine, or more plausibly they reflect other forces, such as differences in medication use, detection bias and reverse causation, or shared risk factors.

Cerebral venous thrombosis (CVT) predominantly affects young to middle-aged women. Scarce data exist on the long-term prognosis. We examined the clinical course of patients with CVT overall and according to age and sex. Using Danish registries, we identified all patients with a first-time primary inpatient diagnosis of CVT from 1996 to 2018 (N = 653, median age 41 years, 67% women) and individuals from the general population, matched on age, sex, and calendar year (N = 65,300). Patients with CVT were at increased risk of venous thromboembolism (VTE) in other sites, ischemic stroke, major bleeding, and mortality. For both sexes, the increased risks of VTE in other sites were most prominent among the young (18-54 years), while the increased risks of ischemic stroke, major bleeding, and mortality were most prominent among the older (≥55 years). Among young women, the 10-year risks of VTE in other sites for CVT patients compared with members of the matched cohort were 2.2% vs. 0.4% (risk difference: 1.8% [95% confidence interval (CI): 0.0, 3.6]). Among older women, compared with members of the matched cohort, the 10-year risks were 12.8% vs. 3.1% (risk difference: 9.7% [95% CI: 1.6, 17.9]) for ischemic stroke, 11.1 vs. 4.6% (risk difference: 6.5% [95% CI: -1.0, 14.1]) for major bleeding, and 43.1% vs. 26.7% (risk difference: 16.4% [95% CI: 3.7, 29.1]) for all-cause mortality. Risks were not elevated for myocardial infarction. Clinicians should be aware of the importance of age and sex heterogeneity in the prognosis of CVT.

To the Editor, Atopic dermatitis is a common and disabling inflammatory skin disease. 1 Compared with those born vaginally, cesarean-delivered children acquire an altered gut microflora owing to delayed gut colonization. 2 The diverged bacteria colonization may disrupt the Th1/ Th2 lymphocyte balance and delay adequate immune system development. Children born by elective cesarean delivery lack the stress response that vaginal delivery induces, which may affect hypothalamic-pituitary-adrenal axis activation, ultimately delaying immune system maturation. As the role of the gut microbiota in the development of atopic dermatitis seems plausible, 3 cesarean delivery may impact the risk of atopic diseases. 4 Thus, we examined whether cesarean delivery increases the risk of atopic dermatitis compared with vaginal delivery. The present study was nested within The Danish Calmette Study, a randomized clinical multicenter trial. 5 A total of 4262 newborns received bacillus Calmette-Guérin (BCG) or no BCG within 7 days of birth and were followed until 13 months of age.Through structured telephone interviews conducted before randomization by trained study staff, we obtained information on baseline characteristics and covariates. Data on delivery method were obtained during randomization. We considered vaginal and vaginal-assisted de-