Burden of respiratory syncytial virus and influenza in adults - a Danish nationwide cohort study.

ADHD medication has proven effective for treating ADHD in adults. Large registry-based studies have generally reported high discontinuation rates over time and focused on different risk factors, including comorbidity, gender, and socioeconomic status. The present mixed-model study examines self-reported factors related to the discontinuation of ADHD medication in Danish adults. It specifically focuses on themes such as the perception of ADHD and the perceived beneficial and adverse effects of the medication, with the aim of identifying patients' reasons either for continuing or discontinuing the prescribed medication overall and in relation to gender. The present study explores patients' self-reported reasons for continuing or discontinuing ADHD medication, as well as the factors that influence their decision to live with or without medication despite having ADHD. The present study employed a mixed-model design and consisted of 1050 Danish adults who redeemed a prescription for ADHD medication for the first time between 2017 and 2019. Questionnaires were distributed by Statistics Denmark to 4748 adults, a representative sample of the 16,284 Danish adults who redeemed a prescription within that period. Discontinuation was defined as a gap of 12 months between redemptions, and questionnaires were sent to an equal number of patients who continued or discontinued ADHD medication. A series of 2 (continuation vs. discontinuation) × 2 (male vs. female) two-way ANOVA was conducted for different main themes, all of which were derived from six patient interviews. The patients who continued medical treatment were more likely to perceive ADHD as a biological illness, whereas those who discontinued treatment were more likely to perceive ADHD as an illness constructed by society. Furthermore, patients who continued medical treatment reported that the medication had a more positive influence on their lives, whereas those who discontinued the medication reported experiencing more negative feelings. Finally, males were more likely than females to perceive ADHD as a socially created illness, while females reported higher scores than males for taking ADHD medication for themselves, being able to work or attend school, being social, and being able to enjoy peaceful alone. The present findings suggest that the perception of ADHD as either a biological or a social construct is central to patients' decisions to continue or discontinue ADHD medication. Moreover, interesting gender differences were found regarding the perception of ADHD and the reasons for taking ADHD medication. From a clinical perspective, these findings underscore the importance of understanding the individual patient's perception of ADHD and highlight the need for relatively close clinical monitoring of patients with ADHD due to their high risk of discontinuing medication.

Distal radius fractures (DRFs) are common in older adults and are associated with osteoporosis and underlying frailty. While hip and spine fractures are associated with increased mortality, the association between DRFs and all-cause mortality remains less clear. We aimed to assess all-cause mortality risk following DRF in Denmark compared with age- and sex-matched controls. We conducted a nationwide, register-based matched cohort study using data from the Danish National Patient Register and Civil Registration System (1998-2018). Adults (≥ 18 years) with a DRF were matched 1:5 to controls by sex and birthdate ± 30 days. Mortality rates per 103persons and mortality rate ratios with 95% confidence intervals (CIs) were calculated at 30, 90, 365, and 730 days after the fracture. We included 190,513 patients with DRF and 952,565 controls (70% female, mean age 59 years). Mortality rates were higher for patients with DRF compared with controls across all age categories, particularly in men and within the first 30 days. Among men, mortality rates ranged from 0.36 to 52.9 per 1,000 persons in patients with DRF and from 0.07 to 20.0 per 1,000 persons in controls. Among women, mortality ranged from 0.16 to 26.3 per 1,000 persons in patients with DRF and from 0.04 to 15.9 per 1,000 persons in controls. Mortality rate ratios were highest for the 50-59 age category (male: 4.60, CI 3.95-5.35, female 3.08, CI 2.80-3.39), decreasing with higher age. Mortality rate ratios stabilized after 365 and 730 days. This nationwide study shows increased all-cause mortality among patients with DRF compared with sex and age-matched controls, with the highest mortality rate within the first 30 days after the fracture. The mortality rate ratio was consistently higher in the age-group 50-59 and among males.

Purpose Severe mental illness (SMI) accounts for over a third of all mental disorders globally, significantly reducing life expectancy and quality of life. Trends in SMI vary, with recent Danish studies reporting both stable and rising rates in the 2000s. This study examines the prevalence (1996–2018) and incidence (2000–2018) of SMI in Denmark, analyzing age- and sex-specific trends using nationwide health registry data. Material and methods The study included individuals aged ≥18 years with a psychiatric hospital diagnosis of SMI, recorded in the Danish National Patient Registry (1995–2018). SMI was defined as moderate to severe depression, bipolar disorder, or psychotic disorder based on ICD-10 classifications. We estimated five-year prevalence (2000–2018) and one-year incidence (1996–2018), stratified by age and sex. Results Between 2000 and 2018, the crude prevalence of depression more than doubled, while bipolar and psychotic disorders increased by 89.6% and 35.0%, respectively. All SMIs increased among individuals aged 18–29. From 1996 to 2018, depression and bipolar disorder incidence rose by 137.5% and 45.1%, respectively, while psychotic disorder incidence declined by 9.5%. The largest incidence increase occurred in the 18–29 age group. Bipolar and psychotic disorder prevalence declined in those ≥70 years. Depression was the most prevalent disorder among individuals ≥90 years. Conclusion SMI prevalence and incidence in Denmark have risen over the past two decades, particularly among younger adults. However, professional, cultural, administrative, and societal factors must be considered before concluding an actual increase in SMI cases.

Ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) have been evaluated as an alternative to S100 calcium binding protein B (S100B), which is mentioned in the Scandinavian guideline for managing mild traumatic brain injury (mTBI). Preanalytical, analytical and diagnostic performance of GFAP/UCH-L1 must be assessed before clinical use. GFAP/UCH-L1 were quantified using the TBI assay on Abbott Alinity. Precision was estimated using internal quality controls, and matrix effects were evaluated using serum and plasma from 30 outpatients. Repeatability and stability at different conditions (25, 4, -20, and -80°C) were evaluated on serum and plasma. GFAP and UCH-L1 serum levels in 30 healthy individuals were determined and compared to S100B levels. Inter-instrumental precision was ≤4.2% for both biomarkers. Random outliers were observed for UCH-L1 in plasma, where 5 measurements deviated >25%. Acceptable storage stability was found for GFAP and UCH-L1. All healthy individuals had GFAP values within the manufacturer's reference interval (6.6 to 70.9 ng/L) and two exceeded the upper limit for UCH-L1 (44.7 to 226.8 ng/L). Four healthy individuals (13%) had GFAP results above cutoff without S100B exceeding its cutoff, while one individual had values of S100B above cutoff but GFAP below cutoff. The analytical precision and storage conditions of GFAP/UCH-L1 were satisfactory. Serum and plasma can be used for measurement of GFAP, whereas UCH-L1 measurement in plasma is not advised until further evaluations are conducted. The manufacturer's upper reference limits may not be suitable for our population. Thorough research on cutoff values is necessary.

CD20 expression is a hallmark of B-cell lymphomas and the target of anti-CD20 monoclonal antibodies. Although CD20 negativity at second-line therapy initiation has been reported, its prevalence and prognostic impact in diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and mantle cell lymphoma (MCL) remain uncertain. We assessed the prevalence of CD20 negativity at second-line initiation and its association with overall survival (OS) in a nationwide cohort. We included consecutive Danish adults with DLBCL, FL, or MCL who received rituximab-based first-line therapy and were diagnosed between 2005 and 2023, for whom CD20 expression was evaluated at second-line initiation. The primary endpoint was OS from second-line therapy, stratified by CD20 status. Multivariable Cox regression analysis was adjusted for age, sex, and subtype-specific international prognostic indices. Among 1375 patients (814 with DLBCL, 339 with FL, 222 with MCL), 168 (12.2%) were CD20- at second-line initiation. Patients who were CD20- had lower complete remission rates to first-line therapy (61.5% vs 72.9%; P < .001) and shorter time to second-line therapy compared with patients who were CD20+ (25.4 vs 35.2 months, respectively; P < .001). Median OS from second-line therapy was 0.9 years for patients who were CD20- and 3.1 years for patients who were CD20+. CD20 negativity was independently associated with shorter OS from second-line therapy in multivariable analysis (hazard ratio, 1.44; 95% confidence interval, 1.18-1.74; P < .001). In conclusion, CD20 negativity is observed in 1 in 8 patients with B-cell lymphomas at second-line initiation and is independently associated with poorer OS from second-line therapy. This underscores an unmet need for therapies targeting non-CD20-dependent antigens.

Patients with chronic kidney disease (CKD) have an increased risk of bone fracture. We aimed to examine the association between parathyroid hormone (PTH), alkaline phosphatase (ALP), and fracture risk in non-dialysis-dependent CKDG3-5. Danish adults with eGFR < 60ml/min/1.73 m2 and measured PTH were identified from nationwide healthcare registers between 2010 and 2022. PTH was standardized to the assay-specified upper normal limit (UNL) and stratified as normal, slightly elevated (1.1-2.0 × UNL), high (2.1-4.0 × UNL), and very high (≥ 4.0 × UNL). ALP was stratified as low to low-normal (< 70 U/L), upper-normal (70-105 U/L), slightly elevated (106-125 U/L), and high (> 125 U/L). Rates of major osteoporotic fracture (MOF; hip, vertebra, wrist, and humerus fracture) and any fracture were estimated in multiple Cox regression models adjusted for relevant confounders. Among 45,611 included individuals adjusted rates of MOF were increased in patients with high PTH (hazard ratio (HR) 1.15, 95% confidence interval (CI) 1.04-1.26, p = 0.005) and very high PTH (HR 1.23, 95% CI 1.04-1.46, p = 0.012), compared to patients with normal PTH. Patients with ALP levels in the upper-normal (HR 1.11, CI 1.02-1.20, p = 0.01), slightly elevated (HR 1.29 CI 1.13-1.47, p < 0.001), and high (HR 1.59, CI 1.39-1.75, p < 0.001) categories showed significantly higher rates of MOF compared to low to low-normal ALP. We found similar HRs of any fracture event stratified by ALP- and PTH levels. Our nationwide observational cohort study demonstrates that PTH and ALP were positively associated with fracture risk in non-dialysis-dependent CKDG3-5.

Five-year inhaled, systemic, and total corticosteroid exposure reduction during anti‒interleukin-5 receptor alpha treatment for severe asthma.

Abstract Objective The COVID-19 pandemic raised concerns about how lockdowns affected health-related behaviours. This study aimed to identify patterns of health-related risk behaviours in Danish adults during the first pandemic wave. Methods We used data from the Danish part of the Collaborative Outcomes study on Health and Functioning during Infection Times (COH-FIT), collected in May 2020 with recruitment through social media and newsletters. Responses were weighed against a Danish representative 2021 sample. Self-reported health-related behaviours were dichotomised into high-risk or not, and Latent Class Analysis was used to identify behavioural subgroups based on sedentary behaviour, media use, substance use, and harmful behaviours. We also examined pre- to during-pandemic changes in behaviour and subgroup demographics. Results Five behavioural subgroups were identified. The largest group (53%) reported low to modest levels of high-risk behaviours. Two medium-sized groups included one (23%) with high media use, tobacco use, and aggression/self-harm, and another (18%) with low levels of most high-risk behaviours but moderate cannabis use and relatively high aggression. Two smaller high-risk groups included one (3%) with aggression, alcohol use, and physical inactivity, and another (2%) with smoking, cannabis, and gaming. Increases from pre-pandemic levels were most common in social media use (47%), TV viewing (46%), and internet use (41%). Conclusions These findings suggest the pandemic intensified pre-existing risk behaviours rather than introducing new ones. Public health strategies should consider behaviour clustering to better support vulnerable subgroups. While limited by a cross-sectional, retrospective design, the study contributes valuable insight into behaviour patterns during societal disruptions.

Objective Asthma is a common chronic respiratory disease affecting people of all ages, but little is known about age-related differences in treatment strategies. The present study aims to explore age-related differences in inhaled corticosteroid (ICS) use and place of asthma management. Methods All Danish adults with a registered secondary care asthma diagnosis or active treatment (>1 redemption of ICS within 365 days) in 2021 were included. Individuals with chronic obstructive pulmonary disease and individuals who migrated or died during the observation period were excluded. Danish national registries provided all treatment data. Results A total of 184,565 patients with asthma (median age 57 [IQR 43–69], 59% female) were included. Overall, 15.7% of the asthma population was treated with high (>800–1600 budesonide-equivalent ug/day) or supratherapeutic (>1600 budesonide-equivalent ug/day) doses of ICS, and the proportion increased with age before reaching a plateau from age 56 onwards (lowest: 18–45 years, 9.7%; highest: 66–75 years, 18.9%; p < .001). Significantly fewer of the patients in the oldest age group were seen in specialist care (highest: 56–65 years, 18.9%; lowest: >86 years, 11.4%; p < .001), and 77.3% of patients exposed to high or supratherapeutic doses of ICS were managed only in primary care. Conclusion The prevalence of high- and supratherapeutic ICS exposure was higher among patients ≥56 years, and when exceeding 76 years of age, a smaller proportion were managed in secondary care. With an increased focus on adverse effects of high-dose ICS treatment and earlier initiation of other treatments, our findings will, hopefully, facilitate less age inequity in asthma management.

Sleep problems constitute a significant public health issue. Previous studies have found that regular leisure-time physical activity has the potential to improve sleep quality. However, stress may influence both physical activity and sleep, acting as a potential moderator in this association. The aim was to examine cross-sectional associations between self-reported leisure-time physical activity and sleep problems, as well as the potential moderating role of stress. The study population consists of 11346 Danish adults (age ≥16 years) from the national representative Danish Health and Morbidity Survey conducted in 2021. Associations between leisure-time physical activity and sleep problems were analysed using multiple adjusted logistic regression, which included an investigation of effect modification by level of self-perceived stress. Adjusted odds ratios (ORs) for experiencing sleep problems were 1.37 [95% confidence interval (CI): 1.20-1.56] among participants who were mainly sedentary during leisure time, and 0.81 (95% CI: 0.72-0.91) among those with moderate to vigorous physical activity level compared to those with light physical activity level. Within all strata of stress levels, higher physical activity was positively associated with lower odds of sleep problems. For example, in the high stress level stratum, ORs were 0.80 (95% CI: 0.63-1.03) and 1.64 (95% CI: 1.28-2.11) in participants who were moderately to vigorously physically active and sedentary, respectively, compared to those who were lightly physically active. Higher levels of leisure-time physical activity appear to be associated with a lower prevalence of sleep problems, even among individuals who experience high levels of stress.

Medical advances have markedly improved survival among patients with cardiovascular disease (CVD). Psychosocial and behavioral factors, including stress and physical activity, are increasingly recognized as key determinants of outcomes in this population. We investigated the association between existing CVD and perceived stress and examined how this association was modulated by physical activity levels in a Danish cohort, accounting for physiological and psychosocial conditions. We analyzed data on 102,650 Danish residents aged 50-65 yr by linking self-reported questionnaire data from the Better Health in Late Life cohort with national health registry data. CVD was identified using hospital discharge diagnoses. Stress was measured with the 10-item Perceived Stress Scale. Physical activity was assessed with a pilot-tested questionnaire. Seven percent of participants had CVD. Compared with those without CVD, they had a higher prevalence of moderate-to-high perceived stress (42% vs. 33%) and a slightly lower prevalence of meeting guideline-recommended physical activity (42% vs. 45%). High stress was associated with physical activity not meeting the recommended level in both groups; however, this association was stronger among those with versus without CVD {prevalence ratio 2.01 [95% confidence interval (CI): 1.89-2.14] vs. 1.52 (95% CI: 1.48-1.56)}. We observed similar associations between stress and cardiovascular risk factors, comorbidity, psychosocial factors, and socioeconomic status. The association between stress and low physical activity persisted after stratification by these conditions. In conclusion, high stress was most strongly associated with low physical activity among adults with CVD. The underlying mechanisms seem to extend beyond physiological pathways and need further investigation.NEW & NOTEWORTHY In this population-based study of over 100,000 Danish adults, participants with cardiovascular disease reported higher perceived stress than those without. Elevated stress was associated with low physical activity across all participants, particularly among those with cardiovascular disease, but also with medical, psychosocial, and behavioral factors. These findings highlight the complex interplay between physiological and nonphysiological determinants of stress, underscoring the importance of integrating stress management and physical activity promotion into cardiovascular prevention and management strategies.

Severe asthma incurs a financial burden on both patients and societies. However, little is known about the long-term financial burden and impact of biologic therapy. All Danish adults initiating biologic therapy for severe asthma between 2016 and 2020 were included and followed retrospectively between 2002 and 2022, both prior to and during biologic therapy. Excess healthcare costs, foregone income and welfare transfers were calculated on an annual basis using a level of education-adjusted, zero-inflated generalised linear model with a gamma distribution and a log-link compared with age, sex, residence and civil status matched comparators. In total, 562 patients and 2207 comparators (median age 56 years, 51% female) were included. Excess healthcare costs during the year prior to biologic therapy were €10 590 and foregone income was €5389 per patient. The excess welfare transfers for patients aged 18-64 were €3335.Prior to biologic therapy, pooling of crude annual costs resulted in an accumulation of €59 364 and €44 155 in excess healthcare costs and foregone income per patient, respectively. Patients aged 18-64 had accumulated €32 021 in excess welfare transfers.Biologic therapy was associated with an increase in excess outpatient care costs (€25 938,+398.6%) compared with the year prior to biologic therapy. Outpatient care costs declined to (€14 486,+78.5%) during treatment year 4. Furthermore, at year 4, reductions in hospitalisations (€-2270, -67.7%) and patient-facing medication costs (€-557, -29.7%) compared with the year prior to biologic therapy were observed. Welfare transfers and foregone income were unaffected. In the present study, patients with severe asthma initiating biologic therapy accumulated a substantial financial burden for both healthcare and welfare institutions, as well as a significant loss of personal income over time. Biologic therapy was associated with increased healthcare costs overall, but did not affect welfare transfers or foregone income.

Background Incidental diagnosis of small renal masses is placing increasing pressure on health care systems. While surgical resection remains standard, ablation has emerged as a less invasive alternative, potentially reducing complications, hospital stays, and costs. However, knowledge about outcomes following ablation remains limited. Purpose To compare the long-term outcomes of ablation, surgical resection, and nephrectomy in patients with T1a renal cell carcinoma (RCC). Materials and Methods This retrospective nationwide-registry cohort study included Danish adults diagnosed with T1a RCC between January 2013 and December 2021. Patients were treated with tumor ablation, surgical resection, or nephrectomy. The primary outcome was progression, defined as distant metastasis or local recurrence. Secondary outcomes included hospital length of stay and 30-day posttreatment hospital contacts, excluding routine scheduled follow-up visits. Progression was analyzed using competing risk regression, and hazard ratios with P values are reported. The χ2 test and Wilcoxon rank sum test were used for other group comparisons. Results A total of 1862 patients (median age, 64 years [IQR, 55-71 years]; 1305 male patients) were included. There was no evidence of a difference in progression risk between the ablation and resection groups after adjusting for confounders (hazard ratio, 1.46 [95% CI: 0.60, 3.56]; P = .40). Local recurrence was most frequent following ablation (ablation: 13 of 540 patients [2.41%]; resection: 12 of 1002 [1.20%]; nephrectomy: zero of 320 [0%]; P = .007), but was treatable with additional procedures. Distant metastasis was most frequent following nephrectomy (ablation: nine of 540 patients [1.67%]; resection: 19 of 1002 [1.90%]; nephrectomy: 14 of 320 [4.38%]; P = .02). Hospital stays were shortest for ablation (median hospitalization time: 0 days for ablation, 2 days for resection, 2 days for nephrectomy; P < .001). Ablation resulted in the fewest 30-day posttreatment hospital contacts (median number of contacts: one [IQR, 0-2] for ablation, one [IQR, 1-2] for resection, one [IQR, 1-2] for nephrectomy; P = .001), suggesting fewer complications with ablation. Conclusion In patients with T1a RCC, treatment with ablation demonstrated comparable progression risk but with fewer complications and shorter hospital stays. © The Author(s) 2026. Published by the Radiological Society of North America under a CC BY 4.0 license. Supplemental material is available for this article.

Epidemiology of Adult Atopic Dermatitis in High-Burden Skin Areas: Results From a Cross-Sectional Patient Survey.

Bone health after 3 years of ETI therapy: a real-world study from the Danish cystic fibrosis cohort.

The prevalence of diabetic retinopathy (DR) is low in Greenland. Factors underlying the low prevalence may potentially protect against the development of DR. Comparing Greenlandic and Danish populations, this register-based study explored differences in risk factors that may explain differences in DR prevalence. Data on DR and risk factors from Greenlandic (n = 1941) and Danish (n = 110343) patients with diabetes were collected from 2019 to 2023 through the Greenlandic electronic medical health records system Cosmic, the Danish Adult Diabetes Registry and the Danish Registry of Diabetic Retinopathy, respectively. Logistic regression models were used to estimate odds and odds ratio (OR) of selected risk factors by cohort (Greenlandic or Danish). Furthermore, the ethnic difference in age and diabetes duration at DR screening was modelled using natural splines. The prevalence of DR was 10.2% in the Greenlandic cohort and 20.9% in the Danish cohort. In multivariate analysis, longer DM duration and higher HbA1c were the most important risk factors of prevalent DR in both cohorts. DM duration longer than 15 years was associated with higher OR in the Danish cohort than in the Greenlandic. In the Danish cohort, overweight and obesity were associated with higher OR of DR (OR = 1.20, 95% CI = 1.02; 1.41 and OR = 1.24, 95% CI = 1.04; 1.48, respectively) while lower ORs were observed for overweight (OR 0.57 95% CI = 0.28; 1.15) or obesity (OR 0.56, 95% CI = 0.30; 1.07) in the Greenlandic cohort. High systolic blood pressure was also associated with prevalent DR in the Danish cohort. Long DM duration was a more prominent risk factor for prevalent DR in the Danish population than in the Greenlandic population. Future studies may address the potentially lower sensitivity to DM duration in the Greenlandic population.

Abstract This study contributes to the sociology of volunteering and crisis research by analyzing the little studied relationship between crisis volunteering (addressing societal crises) and ordinary volunteering (unrelated to crises). This is achieved by examining sector level resilience of ordinary volunteering during crises, possible spill-over between ordinary and crisis volunteering, and the persistence of individual crisis volunteers across the COVID-19 pandemic in 2020–2022 and the reception of Ukrainian refugees fleeing Russia’s invasion in 2022. Using cross-sectional data from random samples of Danish adults before (n2020 = 3,519), during (n2021 = 1,700) and after (n2024 = 1,548) the pandemic, the results show that ordinary volunteering was highly resilient to the pandemic despite a significant reduction during the crisis. A five-round panel (n = 694) further shows that, while ordinary volunteering prior to the crisis correlated with crisis volunteering, crisis volunteering did not spill over into ordinary volunteering after the pandemic. Rather, crisis volunteers persisted engaging in crisis volunteering when Ukrainian refugees arrived. These findings have important implications for civil society studies because the absence of spill-over between ordinary and crisis volunteering suggests that the two types of volunteering operate according to distinct logics and the persistence of crisis volunteers across crisis challenges notions of crisis volunteering being spontaneous and emergent.

Type 2 diabetes (T2D) is increasingly prevalent globally and in Denmark. T2D diagnosed between 18 and 45 years often runs a more aggressive course with heightened morbidity. Diagnosis occurs at glycated haemoglobin (HbA1c) levels exceeding 48 mmol/mol, while prediabetes (HbA1c 39-47 mmol/mol) also predicts excess mortality and 20-40% progress to T2D within a few years. Stress is proposed to contribute to T2D development through lifestyle adaptations or psycho-endocrine pathways. This study explores whether perceived stress and psychosocial stressors (e.g., poor family functioning, limited social contact, adverse life events) in young adulthood correlate with HbA1c levels among Danish young adults. Data were from the West Jutland Cohort Study and included 355 participants who completed a questionnaire at age 32 or 38 and had HbA1c blood samples taken approximately one year later. Perceived stress and psychosocial stressors were categorised at the 25th and 75th percentiles. The outcome was HbA1c (mmol/mol) at age 33 or 39. Multivariable linear regression models, using inverse probability weights to reduce socioeconomic bias, analysed associations between exposure variables and HbA1c, adjusting for sociodemographic characteristics and physical activity. HbA1c tended to vary modestly with perceived stress and psychosocial stressors, with patterns differing by exposure type and estimates lacking statistical significance. Social contact displayed the most pronounced tendency, with low contact corresponding to a 0.31 mmol/mol higher HbA1c [-0.73; 1.35] compared to high social contact. The observed tendencies between some of the psychosocial stressors and HbA1c levels in young adults may indicate potential negative impacts on metabolic health. However, the small effect sizes and the study's small sample size should be considered when interpreting the findings. Further research is warranted to clarify these potential effects and guide future public health strategies.

BackgroundThe HEAD-WINd® study was designed to examine the burden, characteristics and lived experiences of headache disorders in the Danish adult population. By integrating data from surveys, a smartphone application, and national health and social registries, the study addresses limitations of prior epidemiological research.MethodsA random sample of Danish residents aged 18-75years were invited to participate ("base population"). Two nested cohorts were recruited using a population-based approach: (i) a survey cohort consisting of individuals reporting active headache disorders ("headache population") and (ii) a smartphone application cohort, derived from the headache population, which was followed longitudinally for 12weeks. Data from these cohorts were enriched with data from national health and social registries, including information on medication use, hospital records, socioeconomic status and healthcare utilization. An adapted version of the Headache-Attributed Restriction, Disability, Social Handicap and Impaired Participation (HARDSHIP) questionnaire was used to classify multiple headache disorders and assess headache-attributed burden.ResultsOf the 100,030 invited individuals, 28,617 (28.6%) completed the general survey. Among them, 15,571 (54.4%) reported experiencing headache in the preceding year; 14,074 (90.4%) completed the headache-specific survey. In total, 663 individuals (4.7%) participated in the app-based longitudinal study. The mean±SD participant age was 53.2±15.5years, 57.4% were women and the mean±SD body mass index was 26.8±7.4 kg/m².ConclusionsHEAD-WINd® has established a comprehensive, population-based cohort of Danish residents, including individuals both with and without headache disorders. This resource provides a framework for generating population-level insights into the burden and management of headache disorders.