Steinar Krokstad

Cohort Profile: The HUNT Study, Norway

The HUNT Study includes large total population-based cohorts from the 1980ies, covering 125 000 Norwegian participants; HUNT1 (1984-86), HUNT2 (1995-97) and HUNT3 (2006-08). The study was primarily set up to address arterial hypertension, diabetes, screening of tuberculosis, and quality of life. However, the scope has expanded over time. In the latest survey a state of the art biobank was established, with availability of biomaterial for decades ahead. The three population based surveys now contribute to important knowledge regarding health related lifestyle, prevalence and incidence of somatic and mental illness and disease, health determinants, and associations between disease phenotypes and genotypes. Every citizen of Nord-Trøndelag County in Norway being 20 years or older, have been invited to all the surveys for adults. Participants may be linked in families and followed up longitudinally between the surveys and in several national health- and other registers covering the total population. The HUNT Study includes data from questionnaires, interviews, clinical measurements and biological samples (blood and urine). The questionnaires included questions on socioeconomic conditions, health related behaviours, symptoms, illnesses and diseases. Data from the HUNT Study are available for researchers who satisfy some basic requirements (www.ntnu.edu/hunt), whether affiliated in Norway or abroad.

Does a higher educational level protect against anxiety and depression? The HUNT study

The relationship of education to the experience of anxiety and depression throughout adult life is unclear. Our knowledge of this relationship is limited and inconclusive. The aim of this study was to examine (1) whether higher educational level protects against anxiety and/or depression, (2) whether this protection accumulates or attenuates with age or time, and (3) whether such a relationship appears to be mediated by other variables. In a sample from the Nord-Trøndelag Health Study 1995--1997 (HUNT 2) (N=50,918) of adults, the cross-sectional associations between educational level and symptom levels of anxiety and depression were examined, stratified by age. The long-term effects of educational level on anxiety/depression were studied in a cohort followed up from HUNT 1 (1984--1986) to HUNT 2 (N=33,774). Low educational levels were significantly associated with both anxiety and depression. The coefficients decreased with increasing age, except for the age group 65-74 years. In the longitudinal analysis, however, the protective effect of education accumulated somewhat with time. The discrepancy between these two analyses may be due to a cohort effect in the cross-sectional analysis. Among the mediators, somatic health exerted the strongest influence, followed by health behaviors and socio-demographic factors. Higher educational level seems to have a protective effect against anxiety and depression, which accumulates throughout life.

The HUNT study: participation is associated with survival and depends on socioeconomic status, diseases and symptoms

BackgroundPopulation based studies are important for prevalence, incidence and association studies, but their external validity might be threatened by decreasing participation rates. The 50 807 participants in the third survey of the HUNT Study (HUNT3, 2006-08), represented 54% of the invited, necessitating a nonparticipation study.MethodsQuestionnaire data from HUNT3 were compared with data collected from several sources: a short questionnaire to nonparticipants, anonymous data on specific diagnoses and prescribed medication extracted from randomly selected general practices, registry data from Statistics Norway on socioeconomic factors and mortality, and from the Norwegian Prescription Database on drug consumption.ResultsParticipation rates for HUNT3 depended on age, sex and type of symptoms and diseases, but only small changes were found in the overall prevalence estimates when including data from 6922 nonparticipants. Among nonparticipants, the prevalences of cardiovascular diseases, diabetes mellitus and psychiatric disorders were higher both in nonparticipant data and data extracted from general practice, compared to that reported by participants, whilst the opposite pattern was found, at least among persons younger than 80 years, for urine incontinence, musculoskeletal pain and headache. Registry data showed that the nonparticipants had lower socioeconomic status and a higher mortality than participants.ConclusionNonparticipants had lower socioeconomic status, higher mortality and showed higher prevalences of several chronic diseases, whilst opposite patterns were found for common problems like musculoskeletal pain, urine incontinence and headache. The impact on associations should be analyzed for each diagnosis, and data making such analyses possible are provided in the present paper.

Low Socio-Economic Status is Associated with Increased Risk of Frequent Headache: A Prospective Study of 22718 Adults in Norway

Prevalence studies exploring the relation between socio-economic status (SES) and headache have shown conflicting results. This is the first prospective study analysing the relation between SES and risk of headache. A total of 22 685 adults not likely to suffer from headache were classified by SES at baseline in 1984-1986, and responded to a headache questionnaire in a follow-up 11 years later (1995-1997). SES at baseline was defined by educational level, occupation, and income. The risk of frequent headache and chronic headache (> 6, and ≥ 15 days/month, respectively) at follow-up was estimated in relation to SES. When defining SES by educational level or type of occupation, low status was associated with increased risk of frequent and chronic headache at follow-up. The risk of frequent and chronic headache decreased with increasing individual income, but only among men. We conclude that individuals with low SES had higher risk of frequent and chronic headache than people with high SES.

The bidirectional association between depression and insomnia: the HUNT study.

Objective Depression and insomnia are closely linked, yet our understanding of their prospective relationships remains limited. The aim of the current study was to investigate the directionality of association between depression and insomnia. Methods Data were collected from a prospective population-based study comprising the most recent waves of the Nord-Trøndelag Health Study (HUNT) (the HUNT2 in 1995–1997 and the HUNT3 in 2006–2008). A total of 24,715 persons provided valid responses on the relevant questionnaires from both surveys. Study outcomes were onset of depression or insomnia at HUNT3 in persons not reporting the other disorder in HUNT2. Results Both insomnia and depression significantly predicted the onset of the other disorder. Participants who did not have depression in HUNT2 but who had insomnia in both HUNT2 and HUNT3 had an odds ratio (OR) of 6.2 of developing depression at HUNT3. Participants who did not have insomnia in HUNT2 but who had depression in both HUNT2 and HUNT3 had an OR of 6.7 of developing insomnia at HUNT3. ORs were only slightly attenuated when adjusting for potential confounding factors. Conclusions The results support a bidirectional relationship between insomnia and depression. This finding stands in contrast to the previous studies, which have mainly focused on insomnia as a risk factor for the onset of depression.

Patterns of receptive and creative cultural activities and their association with perceived health, anxiety, depression and satisfaction with life among adults: the HUNT study, Norway

Background Cultural participation has been used both in governmental health policies and as medical therapy, based on the assumption that cultural activities will improve health. Previous population studies and a human intervention study have shown that religious, social and cultural activities predict increased survival rate. The aim of this study was to analyse the association between cultural activity and perceived health, anxiety, depression and satisfaction with life in both genders. Methods The study is based on the third population-based Nord-Trøndelag Health Study (2006–2008), including 50 797 adult participants from Nord-Trøndelag County, Norway. Data on cultural activities, both receptive and creative, perceived health, anxiety, depression and satisfaction with life were collected by comprehensive questionnaires. Results The logistic regression models, adjusted for relevant cofactors, show that participation in receptive and creative cultural activities was significantly associated with good health, good satisfaction with life, low anxiety and depression scores in both genders. Especially in men, attending receptive, rather than creative, cultural activities was more strongly associated with all health-related outcomes. Statistically significant associations between several single receptive, creative cultural activities and the health-related outcome variables were revealed. Conclusion This population-based study suggests gender-dependent associations between cultural participation and perceived health, anxiety, depression and satisfaction with life. The results support hypotheses on the effect of cultural activities in health promotion and healthcare, but further longitudinal and experimental studies are warranted to establish a reliable cause–effect relationship.

Material, psychosocial, behavioural and biomedical factors in the explanation of relative socio-economic inequalities in mortality: evidence from the HUNT study

BACKGROUND Previous studies have assessed the relative importance of material, psychosocial and behavioural factors in the explanation of relative socio-economic inequalities in mortality, but research into the contribution of biomedical factors has been limited. Our study examines the relative contribution of (i) material, (ii) psychosocial, (iii) behavioural and (iv) biomedical factors in the explanation of relative socio-economic (educational and income) inequalities in mortality. METHODS Cohort study--baseline data from the Norwegian total county population-based HUNT 2 study linked to mortality data (1995/97 to 2003). In this analysis, 18 247 men and 18 278 women aged 24-80 without severe chronic disease at baseline were eligible. RESULTS No socio-economic inequalities in mortality among women were found. In men, educational- and income-related inequalities in mortality were found with a relative risk for the lowest educational group of 1.67 (1.29-2.15) and the lowest income quartile of 2.03 (1.57-2.70). Together, the four explanatory factors reduced the relative risk of mortality of the lowest educational group to 1.18 (0.90-1.55) and the relative risk of mortality in the lowest income quartile was attenuated to 1.17 (0.83-1.63). Known biomedical factors contributed least to both educational and income inequalities in mortality. CONCLUSIONS Material factors were the most important in explaining income inequalities in mortality amongst men, whereas psychosocial and behavioural factors were the most important in explaining educational inequalities. This suggests that improving the material, psychosocial and behavioural circumstances of men might bring more substantial reductions in relative socio-economic inequalities in mortality.

Trends in health inequalities by educational level in a Norwegian total population study

Objective: To describe levels of inequality and trends in self reported morbidity by educational level in a total Norwegian county population in the mid-1980s and mid-1990s. Design: Two cross sectional health surveys at an interval of 10 years in the Nord-Trøndelag Health Study, HUNT I (1984–86) and HUNT II (1995–97). Setting: Primary health care, total county population study. Participants: Men and women, 25–69 years. Main results: There was a consistent pattern of increasing self reported health problems with decreasing educational level for three health variables: perceived health, any longstanding health problem, and having a chronic condition. A stable or slight decrease in inequalities over time was found. The prevalence odds ratio for perceived health less than good were 2.71 for men (95% confidence intervals (CI): 2.39 to 3.09) and 2.13 for women (95% CI: 1.85 to 2.46) in the first survey, 2.51 for men (95% CI: 2.27 to 2.78) and 2.06 for women (95% CI: 1.88 to 2.26) 10 years later. Conclusions: The magnitude of the socioeconomic gradients in health in this population seemed somewhat lower than in Norway as a whole and close to the average in studies from other European countries. There was a slight trend towards smaller differences despite rapid structural changes in working life, turbulence in economy, and more people experiencing unemployment.

Disability in society—medical and non-medical determinants for disability pension in a Norwegian total county population study

The objective of this study was to describe sociomedical determinants and developments for the medically based disability pension in Norway by linking individual based data from a county health survey to data on disability from the National Insurance Administration. Two cross-sectional total population health surveys with an approximate 10-year interval were conducted in Nord-Trøndelag county, HUNT I (1984-86) and HUNT II (1995-97), which allows for analyses of changes over time, supplied with official incidence data on disability pension. The large-scale variations and overall increasing incidence rates of disability pension in Norway during the last 20 years also applied to the county of Nord-Trøndelag. The prevalence of disability pension generally increased in the population from the mid-1980s to the mid-1990s. A striking finding was a consistent pattern of increasing prevalence of disability pension with decreasing socio-economic status and education. A geographic pattern for disability pension prevalence on a municipality level suggested that structural and cultural factors were important in determining the level of disability in society. Medical determinants alone cannot explain either the dramatic variations or the overall increased incidence rates of disability pension in the last two decades in Norway. The results demonstrate the importance of social, non-medical and contextual determinants for disability pension, how these determinants result in important prevalence differences by socio-economic status, and their impact on the level of disability in society.

Trends in overweight and obesity over 22 years in a large adult population: the HUNT Study, Norway

Some reports indicate that the obesity epidemic may be slowing down or halting. We followed body mass index (BMI) and waist circumference (WC) in a large adult population in Norway (n = 90 000) from 1984–1986 (HUNT1) through 1995–1997 (HUNT2) to 2006–2008 (HUNT3) to study whether this is occurring in Norway. Height and weight were measured with standardized and identical methods in all three surveys; WC was also measured in HUNT2 and HUNT3. In the three surveys, mean BMI increased from 25.3 to 26.5 and 27.5 kg m−2 in men and from 25.1 to 26.2 and 26.9 kg m−2 in women. Increase in prevalence of obesity (BMI ≥ 30 kg m−2) was greater in men (from 7.7 to 14.4 and 22.1%) compared with women (from 13.3 to 18.3 and 23.1%). In contrast, women had a greater increase in abdominal obesity (WC ≥ 102 cm for men and WC ≥ 88 cm for women). There was a continuous shift in the distribution curve of BMI and WC to the right, demonstrating that the increase in body weight was occurring in all weight groups, but the increase of obesity was greatest in the youngest age groups. Our data showed no signs of a halt in the increase of obesity in this representative Norwegian population.