Excess mortality in Denmark, Finland, Norway and Sweden during the COVID-19 pandemic 2020-2022.

BACKGROUND: The Nordic countries represent a unique case study for the COVID-19 pandemic due to socioeconomic and cultural similarities, high-quality comparable administrative register data and notable differences in mitigation policies during the pandemic. We aimed to compare weekly excess mortality in the Nordic countries across the three full pandemic years 2020-2022. METHODS: Using data on weekly all-cause mortality from official administrative registers in Denmark, Finland, Norway and Sweden, we employed time series regression models to assess mortality developments within each pandemic year, with the period 2010-2019 used as reference period. We then compared excess mortality across the countries in 2020-2022, taking differences in population size and age- and sex-distribution into account. Results were age- and sex-standardized to the Danish population of 2020. Robustness was examined with a variety of sensitivity analyses. RESULTS: While Sweden experienced excess mortality in 2020 [75 excess deaths per 100 000 population (95% prediction interval 29-122)], Denmark, Finland and Norway experienced excess mortality in 2022 [52 (14-90), 130 (83-177) and 88 (48-128), respectively]. Weekly death data reveal how mortality started to increase in mid-2021 in Denmark, Finland and Norway, and continued above the expected level through 2022. CONCLUSION: Although the Nordic countries experienced relatively low pandemic excess mortality, the impact and timing of excess mortality differed substantially. These estimates-arguably the most accurate available for any region in capturing pandemic-related excess deaths-may inform future research and policy regarding the complex mortality dynamics in times of a health crisis such as the COVID-19 pandemic.

Disease-specific health spending by age, sex, and type of care in Norway: a national health registry study.

BACKGROUND: Norway is a high-income nation with universal tax-financed health care and among the highest per person health spending in the world. This study estimates Norwegian health expenditures by health condition, age, and sex, and compares it with disability-adjusted life-years (DALYs). METHODS: Government budgets, reimbursement databases, patient registries, and prescription databases were combined to estimate spending for 144 health conditions, 38 age and sex groups, and eight types of care (GPs; physiotherapists & chiropractors; specialized outpatient; day patient; inpatient; prescription drugs; home-based care; and nursing homes) totaling 174,157,766 encounters. Diagnoses were in accordance with the Global Burden of Disease study (GBD). The spending estimates were adjusted, by redistributing excess spending associated with each comorbidity. Disease-specific DALYs were gathered from GBD 2019. RESULTS: The top five aggregate causes of Norwegian health spending in 2019 were mental and substance use disorders (20.7%), neurological disorders (15.4%), cardiovascular diseases (10.1%), diabetes, kidney, and urinary diseases (9.0%), and neoplasms (7.2%). Spending increased sharply with age. Among 144 health conditions, dementias had the highest health spending, with 10.2% of total spending, and 78% of this spending was incurred at nursing homes. The second largest was falls estimated at 4.6% of total spending. Spending in those aged 15-49 was dominated by mental and substance use disorders, with 46.0% of total spending. Accounting for longevity, spending per female was greater than spending per male, particularly for musculoskeletal disorders, dementias, and falls. Spending correlated well with DALYs (Correlation r = 0.77, 95% CI 0.67-0.87), and the correlation of spending with non-fatal disease burden (r = 0.83, 0.76-0.90) was more pronounced than with mortality (r = 0.58, 0.43-0.72). CONCLUSIONS: Health spending was high for long-term disabilities in older age groups. Research and development into more effective interventions for the disabling high-cost diseases is urgently needed.

Agreement between survey- and register-based measures of depression in Denmark.

BACKGROUND: Register-based studies of major depressive disorder (MDD) do not capture all prevalent cases, as untreated cases and diagnoses made by general practitioners are not recorded in the registers. We examined the prevalence and agreement of survey- and register-based measures of depression, and explored sociodemographic and health-related factors that may have influenced this agreement. METHODS: All 32,407 participants in the 2017 Central Denmark Region How are you? survey were linked to hospital and prescription records. A checklist for depressive symptoms within the last 14 days (Major Depression Inventory; MDI) from the survey was compared with register-based assessment of hospital-diagnosed MDD and/or prescriptions for antidepressants. We estimated agreement between survey-based and register-based measures for depression and used logistic regression models to explore selected associated factors. RESULTS: In total, 5.9% of How are you? survey participants screened positive for current depression on the MDI. Of these, 51.3% (95% confidence interval (CI): 49.0-53.6) filled a prescription for an antidepressant medication during the 10 years prior or 2 years following the administration of the survey, and 14.5% (95% CI: 12.9-16.2) were treated for MDD in a psychiatric hospital-based setting. When using a higher threshold of the MDI indicating more severe current depression, 22.8% (95% CI: 19.6-26.1) of those who screened positive also received an MDD diagnosis and 63.4% (95% CI: 59.7-67.2) were prescribed antidepressants during this 12-year period. Among those with current depression, female sex, older age, chronic diseases, hospital-treated self-harm, and being permanently outside the workforce were associated with having a register-based MDD diagnosis or antidepressant prescription. Among those with a register-based depression record, female sex, younger age, hospital-treated self-harm, stress, and severe loneliness were associated with current depression. CONCLUSION: We found that as few as 15% of individuals with current depression in the general Danish population were captured by the psychiatric hospital register, while 51% of these individuals were identifiable in the prescription register. These findings demonstrate that register-based measures significantly underestimate the true prevalence of depression by identifying only the cases that are most severe.

Incidence rates of treated mental disorders before and during the COVID-19 pandemic-a nationwide study comparing trends in the period 2015 to 2021.

BACKGROUND: There is a concern that exposure to psychosocial stressors during the COVID-19 pandemic may have led to a higher incidence of mental disorders. Thus, this study aimed to compare trends in incidence rates of depressive disorder, anxiety disorders, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), and eating disorders in primary- and specialist health care before (2015-2019) and during the COVID-19 pandemic (2020-2021). METHODS: We used aggregated population registry data to calculate incidence rates of mental disorders from primary- (The Norwegian Control and Payment of Health Reimbursements Registry (KUHR)) and specialist (The Norwegian Patient Registry (NPR)) health care. The analyses included all Norwegian residents aged 18-65 during the study period. Incident cases were defined as having no previous registration with the same mental disorder in KUHR (from 2006) or NPR (from 2008). We used linear prediction models and mean models to compare incidence rates and test trends before and during the pandemic. RESULTS: During the pandemic, the incidence rates among women were higher or as predicted for OCD in specialist health care and for eating disorders in both primary- and specialist health care. These findings were strongest among women aged 18-24 years. Incidence rates for depression and phobia/OCD among both genders in primary health care and phobic anxiety disorders among both genders in specialist health care were lower or as predicted. CONCLUSION: The COVID-19 pandemic may have led to more women needing treatment for OCD and eating disorders in the Norwegian population. The decreased incidence rates for some disorders might indicate that some individuals either avoided seeking help or had improved mental health during the pandemic.

Production losses from morbidity and mortality by disease, age and sex in Norway.

AIM: The inclusion of production losses in health care priority setting is extensively debated. However, few studies allow for a comparison of these losses across relevant clinical and demographic categories. Our objective was to provide comprehensive estimates of Norwegian production losses from morbidity and mortality by age, sex and disease category. METHODS: National registries, tax records, labour force surveys, household and population statistics and data from the Global Burden of Disease were combined to estimate production losses for 12 disease categories, 38 age and sex groups and four causes of production loss. The production losses were estimated via lost wages in accordance with a human capital approach for 2019. RESULTS: The main causes of production losses in 2019 were mental and substance use disorders, totalling NOK121.6bn (32.7% of total production losses). This was followed by musculoskeletal disorders, neurological disorders, injuries, and neoplasms, which accounted for 25.2%, 7.4%, 7.4% and 6.5% of total production losses, respectively. Production losses due to sick leave, disability insurance and work assessment allowance were higher for females than for males, whereas production losses due to premature mortality were higher for males. The latter was related to neoplasms, cardiovascular disease and injuries. Across age categories, non-fatal conditions with a high prevalence among working populations caused the largest production losses. CONCLUSIONS: The inclusion of production losses in health care priority debates in Norway could result in an emphasis on chronic diseases that occur among younger populations at the expense of fatal diseases among older age groups.

Contact with primary care physicians among adults with pre-existing common mental health problems during the COVID-19 pandemic: a registry-based study from Norway.

BACKGROUND: During the COVID-19 pandemic, individuals with pre-existing mental health problems may have experienced additional stress, which could worsen symptoms or trigger relapse. Thus, this study aimed to investigate if the number of consultations with general practitioners (GPs) among individuals with a pre-existing common mental health problem during the pandemic differed from pre-pandemic years. METHODS: Data on consultations with GPs among 18-65-year-olds registered with common mental health problems in 2017-2021 were retrieved from the Norwegian Control and Payment of Health Reimbursements Database. Based on data from the pre-pandemic years (2017-2019), we predicted the number of consultations per week for depression, anxiety disorder, phobia/obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), and eating disorders during the pandemic (March 2020-December 2021) among individuals with pre-existing mental health problems. The forecasted and observed trends in GP consultations per week during the pandemic were stratified by diagnosis, gender, and age groups. RESULTS: The observed number of consultations for anxiety disorder, PTSD, and eating disorders were significantly higher than forecasted during extended periods of the two pandemic years. The differences were largest for PTSD (on average 37% higher in men and 47% higher in women during the pandemic), and for eating disorders among women (on average 87% higher during the pandemic). There were only minor differences between the predicted and observed number of consultations for depression and phobia/OCD. CONCLUSIONS: During the pandemic, individuals with a recent history of mental health problems were more likely to seek help for anxiety disorder, PTSD, and eating disorders, as compared to pre-pandemic years.

Impact of the COVID-19 pandemic on mental healthcare consultations among children and adolescents in Norway: a nationwide registry study.

The COVID-19 pandemic and its associated restrictions may have affected children and adolescent's mental health adversely. We cast light on this question using primary and specialist consultations data for the entire population of children of age 6-19 years in Norway (N = 908 272). Our outcomes are the monthly likelihood of having a consultation or hospitalization related to mental health problems and common mental health diagnoses. We compared a pandemic (2019-2021) to a pre-pandemic (2017-2019) cohort using event study and difference-in-difference designs that separate the shock of the pandemic from linear period trends and seasonal variation. We found temporary reductions in all mental health consultations during lockdown in spring 2020. In fall 2020 and winter 2021, consultation volumes in primary care increased, stabilizing at a higher level in 2021. Consultations in specialist care increased from spring 2021. Our findings could suggest a worsening of mental health among adolescents.

Methodological considerations in injury burden of disease studies across Europe: a systematic literature review.

BACKGROUND: Calculating the disease burden due to injury is complex, as it requires many methodological choices. Until now, an overview of the methodological design choices that have been made in burden of disease (BoD) studies in injury populations is not available. The aim of this systematic literature review was to identify existing injury BoD studies undertaken across Europe and to comprehensively review the methodological design choices and assumption parameters that have been made to calculate years of life lost (YLL) and years lived with disability (YLD) in these studies. METHODS: We searched EMBASE, MEDLINE, Cochrane Central, Google Scholar, and Web of Science, and the grey literature supplemented by handsearching, for BoD studies. We included injury BoD studies that quantified the BoD expressed in YLL, YLD, and disability-adjusted life years (DALY) in countries within the European Region between early-1990 and mid-2021. RESULTS: We retrieved 2,914 results of which 48 performed an injury-specific BoD assessment. Single-country independent and Global Burden of Disease (GBD)-linked injury BoD studies were performed in 11 European countries. Approximately 79% of injury BoD studies reported the BoD by external cause-of-injury. Most independent studies used the incidence-based approach to calculate YLDs. About half of the injury disease burden studies applied disability weights (DWs) developed by the GBD study. Almost all independent injury studies have determined YLL using national life tables. CONCLUSIONS: Considerable methodological variation across independent injury BoD assessments was observed; differences were mainly apparent in the design choices and assumption parameters towards injury YLD calculations, implementation of DWs, and the choice of life table for YLL calculations. Development and use of guidelines for performing and reporting of injury BoD studies is crucial to enhance transparency and comparability of injury BoD estimates across Europe and beyond.

Met and unmet need for mental health care before and during the COVID-19 pandemic.

There is a concern that the coronavirus disease 2019 (COVID-19) pandemic will generate large unmet needs for mental health care. Using data from an epidemiological psychiatric diagnostic interview survey (n = 2159) conducted on a probability sample from the general population, the proportions of met and unmet need for mental health care among individuals with and without mental disorders were compared before and during the COVID-19 pandemic. The results showed no statistical difference in met and unmet need for mental health care, but point estimates were suggestive of a higher unmet need for care among those with a current mental disorder after the lock-down period.

Trends in self-reported psychological distress among college and university students from 2010 to 2018.

BACKGROUND: An increase in reported psychological distress, particularly among adolescent girls, is observed across a range of countries. Whether a similar trend exists among students in higher education remains unknown. The aim of the current study was to describe trends in self-reported psychological distress among Norwegian college and university students from 2010 to 2018. METHODS: We employed data from the Students' Health and Wellbeing Study (SHoT), a nationwide survey for higher education in Norway including full-time students aged 18-34. Numbers of participants (participation rates) were n = 6065 (23%) in 2010, n = 13 663 (29%) in 2014 and n = 49 321 (31%) in 2018. Psychological distress was measured using the Hopkins Symptom Checklist-25 (HSCL-25). RESULTS: Overall, a statistically significant increase in self-reported psychological distress was observed over time across gender and age-groups. HSCL-25 scores were markedly higher for women than for men at all time-points. Effect-size of the mean change was also stronger for women (time-by-gender interaction: χ2 = 70.02, df = 2, p < 0.001): in women, mean HSCL-25 score increased from 1.62 in 2010 to 1.82 in 2018, yielding a mean change effect-size of 0.40. The corresponding change in men was from 1.42 in 2010 to 1.53 in 2018, giving an effect-size of 0.26. CONCLUSIONS: Both the level and increase in self-reported psychological distress among Norwegian students in higher education are potentially worrying. Several mechanisms may contribute to the observed trend, including changes in response style and actual increase in distress. The relative low response rates in SHoT warrant caution when interpreting and generalising the findings.

Association of Household Income With Life Expectancy and Cause-Specific Mortality in Norway, 2005-2015.

Importance: Examining causes of death and making comparisons across countries may increase understanding of the income-related differences in life expectancy. Objectives: To describe income-related differences in life expectancy and causes of death in Norway and to compare those differences with US estimates. Design and Setting: A registry-based study including all Norwegian residents aged at least 40 years from 2005 to 2015. Exposures: Household income adjusted for household size. Main Outcomes and Measures: Life expectancy at 40 years of age and cause-specific mortality. Results: In total, 3 041 828 persons contributed 25 805 277 person-years and 441 768 deaths during the study period (mean [SD] age, 59.3 years [13.6]; mean [SD] number of household members per person, 2.5 [1.3]). Life expectancy was highest for women with income in the top 1% (86.4 years [95% CI, 85.7-87.1]) which was 8.4 years (95% CI, 7.2-9.6) longer than women with income in the lowest 1%. Men with the lowest 1% income had the lowest life expectancy (70.6 years [95% CI, 69.6-71.6]), which was 13.8 years (95% CI, 12.3-15.2) less than men with the top 1% income. From 2005 to 2015, the differences in life expectancy by income increased, largely attributable to deaths from cardiovascular disease, cancers, chronic obstructive pulmonary disease, and dementia in older age groups and substance use deaths and suicides in younger age groups. Over the same period, life expectancy for women in the highest income quartile increased 3.2 years (95% CI, 2.7-3.7), while life expectancy for women in the lowest income quartile decreased 0.4 years (95% CI, -1.0 to 0.2). For men, life expectancy increased 3.1 years (95% CI, 2.5-3.7) in the highest income quartile and 0.9 years (95% CI, 0.2-1.6) in the lowest income quartile. Differences in life expectancy by income levels in Norway were similar to differences observed in the United States, except that life expectancy was higher in Norway in the lower to middle part of the income distribution in both men and women. Conclusions and Relevance: In Norway, there were substantial and increasing gaps in life expectancy by income level from 2005 to 2015. The largest differences in life expectancy between Norway and United States were for individuals in the lower to middle part of the income distribution.

Prevalence and stability of mental disorders among young adults: findings from a longitudinal study.

BACKGROUND: Mental disorders often have onset early in life, contribute substantially to the global disease burden, and may interfere with young people's ability to complete age-relevant tasks in important developmental periods. However, knowledge about prevalence and course of mental disorders in young adulthood is sparse. The aim of the current study was to estimate prevalence and stability of mental disorders from the twenties to the thirties/forties. METHODS: DSM-IV mental disorders were assessed with the Composite International Diagnostic Interview in two waves (1999-2004 and 2010-2011) in 1623 young adult Norwegian twins (63.2% women, aged 19-29 years in wave 1). RESULTS: In wave 1, the 12-month prevalence of any mental disorder among people in the twenties was 19.8% (men) and 32.4% (women), anxiety disorders: 9.6% (men) and 26.7% (women), anxiety disorders excluding specific phobias: 2.5% (men) and 6.9% (women), major depressive disorder (MDD): 4.4% (men) and 7.2% (women), and alcohol use disorder (AUD): 8.7% (men) and 4.4% (women). The prevalence of any mental disorder decreased from the twenties to the thirties/forties. This was due to a decrease in AUD and specific phobias. Anxiety disorders in the twenties predicted anxiety disorders and MDD ten years later, even when controlling for the association between these disorders in the twenties. MDD in the twenties predicted MDD ten years later. At both ages, two-week and 12-month prevalence estimates differed markedly for MDD - indicating an episodic course. CONCLUSIONS: Common mental disorders are highly prevalent among young adults in the twenties, and somewhat less prevalent in the thirties/forties. Those who suffer from one mental disorder in the twenties are at considerably increased risk for suffering from a disorder ten years later as well. This may have significant implications for young people's ability to attain education, establish a family, and participate in occupational life.

The gender gap in accrued pension rights - an indicator of women's accumulated disadvantage over the course of working life. The Hordaland Health Study (HUSK).

AIMS: Economic gender equality is one of the goals of the Nordic Welfare states. Despite this, there is a considerable gender gap in pensionable income in the European Union, and an unmet need for measures that absorb more of the complexity associated with accumulated (dis)advantages across gender and population groups. The aims of the present study were to examine the gender difference in association between average earned pension points and 1) education and 2) current occupational prestige, and to discuss pension points as a possible indicator of accumulated disadvantages. METHODS: We linked a community-based survey, the Hordaland Health study (HUSK), to the national register of insurance benefits (FD-trygd). This made it possible to trace gendered patterns of economic (dis)advantages associated with educational level, career development and gainful work over the life course for 17,275 individuals. RESULTS: We found profound differences in earned accrued pension rights between men and women across socioeconomic strata, and a significant interaction between pension rights and gender in the association with education and occupational prestige. Our findings indicate that men, as a group, may have lower educational attainment and occupational prestige than women, and still earn more pension points throughout their career. These differences place women at risk for future economic strain and deprivation over and above their similarly educated and positioned male counterparts. CONCLUSIONS: We suggest that accrued pension rights may be a relevant measure of accumulated (dis)advantages over the course of working life, and a useful indicator when gender equality is measured and discussed.

No gold standard for calculating excess mortality. / Ingen fasit for beregning av overdødelighet.

When observed mortality is higher than expected mortality, it is referred to as excess mortality. While observed mortality is easy to quantify, calculating expected mortality is challenging. Using different methods can sometimes lead to major differences in excess mortality estimates.

Disease burden in Norway in 2016. / Sykdomsbyrden i Norge i 2016.

BAKGRUNN: For å kunne møte helseutfordringer i befolkningen trenger vi oversikt over befolkningens helsetilstand. I Norge har vi tradisjonelt hatt god oversikt over dødsårsaker, men vi vet mindre om byrden fra tilstander som medfører sykelighet, såkalt ikke-dødelig helsetap. Vårt mål var å beskrive den totale sykdomsbyrden i Norge i 2016, utviklingen de siste ti årene samt kjønnsforskjeller i sykdomsbyrde. MATERIALE OG METODE: Vi brukte resultater fra det globale sykdomsbyrdeprosjektet Global Burden of Diseases, Injuries and Risk Factors Study (GBD), som kvantifiserer ikke-dødelig helsetap slik at det kan måles på samme skala som dødelighet i form av tapte leveår. Summen av tapte leveår og ikke-dødelig helsetap gir sykdomsbyrdemålet helsetapsjusterte leveår (DALY). RESULTATER: Ikke-smittsomme sykdommer som hjerte- og karsykdom, kreft, kronisk obstruktiv lungesykdom og demens var viktige årsaker til tapte leveår hos begge kjønn i Norge i 2016. Ikke-dødelig helsetap utgjorde 52 % av sykdomsbyrden målt i helsetapsjusterte leveår. Spesielt muskel- og skjelettsykdommer, psykiske lidelser og ruslidelser var viktige. De siste ti årene har sykdomsbyrden (i aldersjusterte rater) sunket for mange tilstander som medfører tapte leveår, men ikke for tilstander som gir ikke-dødelig helsetap. FORTOLKNING: Ikke-dødelig helsetap utgjør en stor og økende andel av sykdomsbyrden i den norske befolkningen, noe som vil gi nye utfordringer for helsevesenet.

Burden of musculoskeletal disorders in the Eastern Mediterranean Region, 1990-2013: findings from the Global Burden of Disease Study 2013.

OBJECTIVES: We used findings from the Global Burden of Disease Study 2013 to report the burden of musculoskeletal disorders in the Eastern Mediterranean Region (EMR). METHODS: The burden of musculoskeletal disorders was calculated for the EMR's 22 countries between 1990 and 2013. A systematic analysis was performed on mortality and morbidity data to estimate prevalence, death, years of live lost, years lived with disability and disability-adjusted life years (DALYs). RESULTS: For musculoskeletal disorders, the crude DALYs rate per 100 000 increased from 1297.1 (95% uncertainty interval (UI) 924.3-1703.4) in 1990 to 1606.0 (95% UI 1141.2-2130.4) in 2013. During 1990-2013, the total DALYs of musculoskeletal disorders increased by 105.2% in the EMR compared with a 58.0% increase in the rest of the world. The burden of musculoskeletal disorders as a proportion of total DALYs increased from 2.4% (95% UI 1.7-3.0) in 1990 to 4.7% (95% UI 3.6-5.8) in 2013. The range of point prevalence (per 1000) among the EMR countries was 28.2-136.0 for low back pain, 27.3-49.7 for neck pain, 9.7-37.3 for osteoarthritis (OA), 0.6-2.2 for rheumatoid arthritis and 0.1-0.8 for gout. Low back pain and neck pain had the highest burden in EMR countries. CONCLUSIONS: This study shows a high burden of musculoskeletal disorders, with a faster increase in EMR compared with the rest of the world. The reasons for this faster increase need to be explored. Our findings call for incorporating prevention and control programmes that should include improving health data, addressing risk factors, providing evidence-based care and community programmes to increase awareness.

Midlife mental distress and risk for dementia up to 27 years later: the Nord-Trøndelag Health Study (HUNT) in linkage with a dementia registry in Norway.

BACKGROUND: Dementia is an increasing public health challenge, and the number of individuals affected is growing rapidly. Mental disorders and symptoms of mental distress have been reported to be risk factors for dementia. The aim of this study was to examine whether midlife mental distress is a predictor for onset of dementia later in life. METHODS: Using data from a large population-based study (The Nord-Trøndelag Health Study; HUNT1) linked to a dementia registry (The Health and Memory study; HMS) enabling a maximum 27 years of follow-up, we ascertained mental distress and subsequent dementia status for 30,902 individuals aged 30-60 years at baseline. In HUNT1, self-reported mental distress was assessed using the four-item Anxiety and Depression Index (ADI-4). Dementia status was ascertained from HMS, which included patient and caregiver history, cognitive testing and clinical and physical examinations from the hospitals and nursing homes serving the catchment area of HUNT1. In the main analysis, unadjusted and adjusted logistic regression models were computed for the prospective association between mental distress and dementia. In secondary analyses, two-way age and gender interactions with mental distress on later dementia were examined. RESULTS: A 50% increased odds for dementia among HUNT1-participants reporting mental distress was found (crude odds ratio (OR): 1.52; 95% CI 1.15-2.01), and a 35% increase in the fully adjusted model (OR 1.35; 95% CI 1.01-1.80). In secondary analyses, we found evidence for a two-way interaction with age on the association between mental distress and dementia (p = 0.030): the age- and gender adjusted OR was 2.44 (95% CI 1.18-5.05) in those aged 30-44 years at baseline, and 1.24 (0.91-1.69) in 45-60 year olds. CONCLUSIONS: Our results indicate an association between midlife mental distress and increased risk of later dementia, an association that was stronger for distress measured in early compared to later midlife. Mental distress should be investigated further as a potentially modifiable risk factor for dementia.

Monthly variations in self-report of time-specified and typical alcohol use: the Nord-Trøndelag Health Study (HUNT3).

BACKGROUND: Aggregated measures are often employed when prevalence, risk factors and consequences of alcohol use in the population are monitored. In order to avoid time-dependent bias in aggregated measures, reference periods which assess alcohol use over longer time-periods or measures assessing typical alcohol use are considered superior to reference periods assessing recent or current alcohol consumption. Alcohol consumption in the population is found to vary through the months of the year, but it is not known whether monthly variations in actual alcohol use affects self-reports of long-term or typical alcohol consumption. Using data from a large, population-based study with data-collection over two years, the aim of the present study was to examine whether self-reported measures of alcohol use with different reference periods fluctuated across the months of the year. METHODS: Participants in the third wave of the Nord-Trøndelag Health Survey (HUNT3) answered questions regarding alcohol use in the last 4 weeks, weekly alcohol consumption last twelve months, typical weekly binge drinking and typical number of alcoholic drinks consumed in a 14 day period. For each of the alcohol measures, monthly variations in reporting were estimated and compared to the overall average. RESULTS: Monthly variations in self-reported alcohol use were found across all alcohol measures regardless of reference period. A general tendency was found for highest level of alcohol use being reported during the summer season, however, the highest number of individuals who reported alcohol use in the last 4 weeks was found in January. Women reported substantially larger increase in weekly binge drinking during the summer months than men. CONCLUSIONS: Self-reports of alcohol use over longer time and typical alcohol use varies according to the month the respondents are assessed. Monthly variations should therefore be taken into account when designing, analyzing and interpreting data from population-based studies aimed to examine descriptive and analytical characteristics of alcohol use in the population.