Cohort Profile: The HUNT Study, Norway KROKSTAD, S; LANGHAMMER, A; HVEEM, K ...
International journal of epidemiology,
08/2013, Volume:
42, Issue:
4
Journal Article
Peer reviewed
Open access
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.
The aim of this study was to analyse changes in body weight and height, and the changes in the prevalence of overweight and obesity.
Prospective population based study with 11-year follow-up.
...Norwegian men (n=21565) and women (n=24337) aged 20 years or more who participated in two health surveys, the first in 1984-1986 and the other in 1995-1997.
Height and weight were measured by using standardised procedures at both surveys, and we computed body mass index (BMI) as weight in kilo divided by the squared value of height in meters.
Participants who were younger than 50 years at the first survey showed a large increase in body weight, and men and women aged 20-29 years increased their weight with an average of 7.9 kg and 7.3 kg, respectively. Contradictory, participants who were 70 years or older had on average a weight loss. The prevalence of overweight (BMI=25.0-29.9 kg/m(2)) and obesity (BMI>/=30 kg/m(2)) increased between the surveys, especially in the youngest age groups. Overall, the proportion classified as obese increased from 6.7 to 15.5% among men and from 11.0 to 21.0% among women. Some of this increase was due to a reduction in height, which was most pronounced in the oldest age groups.
During approximately 10 years, body weight increased in all age groups below 70 years, and the prevalence of overweight and obese persons was approximately 20% higher at the second survey compared with the first survey.
Summary
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.
The ballistic properties of the aluminium alloy AA6070 in different tempers are studied, using target plates of 20 mm thickness in tempers O (annealed), T4 (naturally aged), T6 (peak strength) and T7 ...(overaged). The stress–strain behaviour of the different tempers was characterised by quasi-static tension tests and was found to vary considerably with temper in regards to strength, strain hardening and ductility. Ballistic impact tests using 7.62 mm APM2 bullets were then carried out, and the ballistic limit velocities were obtained for all tempers. In the material tests it was shown that the O-temper was most ductile and almost no fragmentation took place during the ballistic impact tests. The T6-temper proved to be least ductile, and fragmentation was commonly seen. The experiments show that despite fragmentation, strength is a more important feature than ductility in ballistic impact for this alloy, at least for the given projectile and within the velocity range investigated. A thermoelastic–thermoviscoplastic constitutive relation and a ductile fracture criterion were determined for each temper, and finite element analyses were performed using the IMPETUS Afea Solver with fully integrated 3rd-order 64-node hexahedrons. The numerical simulations predicted the same variation in ballistic limit velocity with respect to temper condition as found in the experiments, but the results were consistently to the conservative side. In addition, analytical calculations using the cylindrical cavity expansion theory (CCET) were carried out. The ballistic limit velocities resulting from these calculations were found to be in good agreement with the experimental data.
► The ballistic properties of AA6070 in four different tempers have been studied. ► Based on the material tests, material models were identified for each temper. ► Ballistic tests show that material strength is more important than local ductility. ► FEM and CCET calculations are carried out and compared with experimental data. ► Aluminium alloys are found to have comparable perforation resistance to steels.
Low iron (Fe) stores may result in increased absorption of divalent metals, in particular cadmium (Cd). We have previously shown that in non-smoking women participating in the Norwegian HUNT2 cohort ...study this also included other divalent metals, e.g. manganese (Mn) and cobalt (Co). The diet is the main source of metals in non-smoking individuals, whereas in smoking individuals tobacco smoke contributes significant amounts of Cd and lead (Pb). The aim of the present study was to investigate the impact of smoking on the relationship between low iron status and divalent metals.
Blood concentrations of the divalent metals Cd, Mn, Co, Pb, copper (Cu) and zinc (Zn), determined using an Element 2 sector field mass spectrometer (ICP-MS), were investigated in smoking women of fertile age (range 21–55 years) (n=267) from the HUNT2 cohort. Among these, 82 were iron-deplete (serum ferritin<12μg/L) and 28 had iron deficiency anaemia (serum ferritin<12μg/L & Hb<120g/L). 150 (56%) women smoked 10 or more cigarettes daily, 101 (38%) had smoked for more than 20 years, and 107 (40%) had smoked for 11–20 years. Results from the smoking population were compared with results from our previous study in non-smoking women (n=448) of which 132 were previous smokers, all from the same cohort.
Increasing concentrations of Cd in blood were observed for previous smokers, low-to-moderate smokers and high intensity smokers in all subgroups compared to never smokers, and according to age groups, education level, BMI and serum ferritin. Smokers had higher Pb concentrations than non-smokers in all subgroups, but less pronounced than for Cd. Smoking was not associated with Mn and Co concentrations in blood.
In multiple regression models, low ferritin was associated with increased blood concentrations of Cd, Pb, Mn and Co. Ferritin was strongly associated with Cd at low smoking intensity, but was not a significant factor in heavy smokers, where intensity and duration of smoking emerged as main determinants. Ferritin associations with Co and Pb varied with tertiles of blood Cd. Ferritin emerged as the main determinant of blood Co and Mn, while for blood Pb, age and smoking intensity had higher impact. Cu and Zn remained within reference values and no significant associations with ferritin were found. Strong positive associations between blood concentrations of Pb, Mn, Cd and Co were observed, also when controlled for their common association with ferritin. Apart from these associations, the models showed no significant interactions between the divalent metals studied. Mild anaemia (110<Hb<120g/L) did not seem to have any effect independent of low ferritin.
The results indicate that low serum ferritin facilitates absorption of certain divalent metal ions in female smokers as well as the previously shown effect in non-smokers. Even if smoking provides Pb and Cd, the mutual associations between Cd and other divalent metals in blood persisted in medium and heavy smokers. This indicates that the interrelationship between Cd and divalent metals not only reflect effects on the absorption, but possibly also on kinetic processes such as transportation in blood and other compartments, including excretion.
Overweight and obesity increase the risk of elevated blood pressure, but the knowledge of the effect of weight change on blood pressure is sparse.
To investigate the association between change in ...body mass index (BMI) and change in diastolic blood pressure (DBP), systolic blood pressure (SBP), and hypertension status.
Two population-based cross-sectional studies, one in 1984-86 and the other in 1995-97.
The Nord-Trondelag Health Study (HUNT).
We included 15,971 women and 13,846 men who were 20 y or older at the first survey, without blood pressure medication at both surveys and without diabetes, cardiovascular disease or dysfunction in daily life at baseline.
Weight, height and blood pressure were measured standardised. Change in BMI was categorised as stable (initial BMI+/-0.1 kg/m2 each follow-up year), increased or decreased, and BMI was categorised by using World Health Organisation's categorisation (underweight BMI: <18.5 kg/m2, normal weight BMI: 18.5-24.9 kg/m2, overweight BMI: 25.0-29.9 kg/m2, obesity BMI> or =30 kg/m2).
An increase in BMI and a decrease in BMI were significantly associated with increased and decreased SBP and DBP, respectively, compared to a stable BMI in both genders and all age groups, although the strongest effect was found among those who were 50 y and older. The adjusted odds ratio for having hypertension at HUNT 2 was 1.8 (95% confidence interval (CI): 1.5, 2.2) among women and 1.6 (95% CI: 1.4,1.8) among men aged 20-49 y who increased their BMI compared to those who had stable BMI. A similar, but weaker association was found among women and men aged 50 y or more. The mean change in both SBP and DBP was higher for those who changed BMI category from first to the second survey than for those who were in the same BMI class at both surveys.
Our result supports an independent effect of change in BMI on change in SBP and DBP in both women and men, and that people who increase their BMI are at increased risk for hypertension.
In a previous paper, we presented a scaling law for the ballistic-limit velocity for the 7.62 mm APM2 bullet and aluminum armor plates. This scaling law predicts that the ballistic-limit velocity is ...proportional to the square root of the product of plate thickness and a material strength term. In this note, we present additional ballistic data from the US Army Research Laboratory (ARL) and the Norwegian University of Science and Technology (NTNU) to show that this scaling law is accurate for eight aluminum alloys, plate thicknesses from 10 to 60 mm, and yield strengths from 51 to 414 MPa.
Abstract Background and aims We sought to explore associations between serum 25-hydroxyvitamin D 25(OH)D levels and non-alcoholic fatty liver disease NAFLD in an integrated healthcare delivery system ...in the U.S. Methods and results Six hundred and seven NAFLD cases were randomly matched 1:1 with controls for age, sex, race and season of measurement. Conditional logistic regression was used to evaluate if serum 25(OH)D levels were associated with increased odds of NAFLD (diagnosed by ultrasound) after adjusting for body mass index and history of diabetes, renal, peripheral vascular and liver diseases (model 1) and also for hypertension (model 2). Mean (SD) serum 25(OH)D level was significantly lower in the group with NAFLD as compared with that in the matched control group (75 ± 17 vs. 85 ± 20 nmol/L 30 ± 7 vs. 34 ± 8 ng/mL, P < 0.001). Inadequate 25(OH)D status progressively increased the odds of NAFLD when classified categorically as sufficient (25(OH)D 75 nmol/L >30 ng/mL, reference group), insufficient (37–75 nmol/L 15–30 ng/mL; adjusted odds ratio OR: 2.40, 95% confidence interval CI: 0.90–6.34) or deficient (<37 nmol/L <15 ng/mL; adjusted OR: 2.56, 95% CI: 1.27–5.19). When modeled as a continuous variable, increased log10 25(OH)D was inversely associated with the risk of prevalent NAFLD (adjusted OR: 0.25, 95% CI: 0.064–0.96, P = 0.02). Conclusion Compared with matched controls, patients with NAFLD have significantly decreased serum 25(OH)D levels, suggesting that low 25(OH)D status might play a role in the development and progression of NAFLD.
Background: Migraine with aura (MA) has been found to be a risk factor for cardiovascular disease including ischaemic stroke and myocardial infarction. Studies have also reported a higher prevalence ...of unfavourable cardiovascular risk factors amongst migraineurs, but results have been conflicting as to whether this is restricted to MA or also holds true for migraine without aura (MO). This study aims to examine the relation between headache and cardiovascular risk factors in a large cross‐sectional population‐based study.
Methods: A total of 48 713 subjects (age ≥20 years) completed a headache questionnaire and were classified according to the headache status in the Nord‐Trøndelag Health Study in Norway 1995–1997 (HUNT 2). Framingham 10‐year risk for myocardial infarction and coronary death could be calculated for 44 098 (90.5%) of these. Parameters measured were blood pressure, body mass index, serum total and high‐density lipoprotein cholesterol.
Results: Compared to controls, Framingham risk score was elevated in non‐migraine headache sufferers (OR 1.17, 95% CI 1.10–1.26), migraineurs without aura (OR 1.17, 95% CI 1.04–1.32) and most pronounced amongst migraineurs with aura (OR 1.54, 95% CI 1.21–1.95). Framingham risk score consistently increased with headache frequency. For non‐migrainous headache and MO, the increased risk was accounted for by the lifestyle factors smoking, high BMI and low physical activity, whilst such factors did not explain the elevated risk associated with MA.
Conclusions: Both MA, MO and non‐migrainous headache are associated with an unfavourable cardiovascular risk profile, but different mechanisms seem to underlie the elevated risk in MA than in the other headache types.
To examine the prevalence of thyroid disease and dysfunction including thyroid autoimmunity in Norway.
All inhabitants 20 years and older (94009) in Nord-Trondelag were invited to participate in a ...health survey with a questionnaire and blood samples.
The prevalence of former diagnosed hyperthyroidism was 2.5% in females and 0.6% in males, hypothyroidism 4.8% and 0.9%, and goitre 2.9% and 0.4% respectively. In both sexes the prevalence increased with age. In individuals without a history of thyroid disease the median, 2.5 and 97.5 percentiles for TSH (mU/l) were 1.80 and 0.49-5.70 for females and 1. 50 and 0.56-4.60 for males. The TSH values increased with age. When excluding individuals with positive thyroid peroxidase antibodies (TPOAb) (>200U/ml), the 97.5 percentiles dropped to 3.60 mU/l and 3. 40 mU/l respectively. The prevalence of pathological TSH values in females and males were TSH >/=10mU/l 0.90% and 0.37%; TSH 4.1-9. 9mU/l 5.1% and 3.7%; and TSH</=0.05mU/l 0.45% and 0.20% respectively. The prevalence of positive TPOAb (>200U/ml) was 13.9% in females and 2.8% in males. In females the lowest percentage (7.9%) of positive TPOAb was seen with TSH 0.2-1.9mU/l and increased both with lower and higher levels of TSH. The percentage of males with positive TPOAb was lower than in females in all TSH groups except for those with TSH>10mU/l (85% TPOAb positive).
In spite of a high prevalence of recognised thyroid disease in the population a considerable number of inhabitants have undiagnosed thyroid dysfunction and also positive TPOAb.
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