Abstract: BACKGROUND: Raised blood pressure is an important risk factor for cardiovascular diseases and chronic kidney disease. We estimated worldwide trends in mean systolic and mean diastolic blood pressure, and the prevalence of, and number of people with, raised blood pressure, defined as systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher. METHODS: For this analysis, we pooled national, subnational, or community population-based studies that had measured blood pressure in adults aged 18 years and older. We used a Bayesian hierarchical model to estimate trends from 1975 to 2015 in mean systolic and mean diastolic blood pressure, and the prevalence of raised blood pressure for 200 countries. We calculated the contributions of changes in prevalence versus population growth and ageing to the increase in the number of adults with raised blood pressure. FINDINGS: We pooled 1479 studies that had measured the blood pressures of 19.1 million adults. Global age-standardised mean systolic blood pressure in 2015 was 127.0 mm Hg (95% credible interval 125.7-128.3) in men and 122.3 mm Hg (121.0-123.6) in women; age-standardised mean diastolic blood pressure was 78.7 mm Hg (77.9-79.5) for men and 76.7 mm Hg (75.9-77.6) for women. Global age-standardised prevalence of raised blood pressure was 24.1% (21.4-27.1) in men and 20.1% (17.8-22.5) in women in 2015. Mean systolic and mean diastolic blood pressure decreased substantially from 1975 to 2015 in high-income western and Asia Pacific countries, moving these countries from having some of the highest worldwide blood pressure in 1975 to the lowest in 2015. Mean blood pressure also decreased in women in central and eastern Europe, Latin America and the Caribbean, and, more recently, central Asia, Middle East, and north Africa, but the estimated trends in these super-regions had larger uncertainty than in high-income super-regions. By contrast, mean blood pressure might have increased in east and southeast Asia, south Asia, Oceania, and sub-Saharan Africa. In 2015, central and eastern Europe, sub-Saharan Africa, and south Asia had the highest blood pressure levels. Prevalence of raised blood pressure decreased in high-income and some middle-income countries; it remained unchanged elsewhere. The number of adults with raised blood pressure increased from 594 million in 1975 to 1.13 billion in 2015, with the increase largely in low-income and middle-income countries. The global increase in the number of adults with raised blood pressure is a net effect of increase due to population growth and ageing, and decrease due to declining age-specific prevalence. INTERPRETATION: During the past four decades, the highest worldwide blood pressure levels have shifted from high-income countries to low-income countries in south Asia and sub-Saharan Africa due to opposite trends, while blood pressure has been persistently high in central and eastern Europe. FUNDING: Wellcome Trust.

Abstract: OBJECTIVE: In addition to hepatocellular cancer, HFE C282Y homozygotes are reported to have increased risk of colorectal cancer and breast cancer. This study was done to further explore the cancer risk in C282Y homozygotes. MATERIAL AND METHODS: We studied cancer incidence in 292 homozygotes and 62,568 others that participated in the HUNT 2 population screening in 1995-1997. Using Cox proportional hazard models, we estimated cancer hazard ratio as a function of C282Y homozygosity and several screening variables including serum transferrin saturation, alcohol consumption and daily smoking. RESULTS: Cancer was diagnosed in 36 homozygotes, five of which had two cancer diagnoses. The overall cancer incidence was not increased in C282Y homozygotes (hazard ratio 1.10 [95% CI 0.60-2.03] in women and 0.94 [95% CI 0.53-1.66] in men). However, homozygous men had increased risk of colorectal cancer (hazard ratio 3.03 [95% CI 1.17-7.82], p = 0.022) and primary liver cancer (hazard ratio 54.0 [95% CI 2.68-1089], p = 0.009). The risk of breast cancer in homozygous women was not increased (hazard ratio 1.13 [95% CI 0.35-3.72]). Adjusted for other variables including C282Y homozygosity, very low and very high serum transferrin saturation were associated with increased overall cancer incidence. CONCLUSIONS: C282Y homozygosity is associated with increased risk of colorectal cancer and hepatocellular cancer in men. In the general population, individuals with a very low or a very high serum transferrin saturation may have increased cancer risk.

Abstract: CONTEXT: Serum TSH in the upper part of the reference range may sometimes be a response to autoimmune thyroiditis in early stage and may therefore predict future hypothyroidism. Conversely, relatively low serum TSH could predict future hyperthyroidism. OBJECTIVE: The objective of the study was to assess TSH within the reference range and subsequent risk of hypothyroidism and hyperthyroidism. DESIGN AND SETTING: This was a prospective population-based study with linkage to the Norwegian Prescription Database. SUBJECTS: A total of 10,083 women and 5,023 men without previous thyroid disease who had a baseline TSH of 0.20-4.5 mU/liter and who participated at a follow-up examination 11 yr later. MAIN OUTCOME MEASURES: Predicted probabilities of developing hypothyroidism or hyperthyroidism during follow-up, by categories of baseline TSH, were estimated. RESULTS: During 11 yr of follow-up, 3.5% of women and 1.3% of men developed hypothyroidism, and 1.1% of women and 0.6% of men developed hyperthyroidism. In both sexes, the baseline TSH was positively associated with the risk of subsequent hypothyroidism. The risk increased gradually from TSH of 0.50-1.4 mU/liter [women, 1.1%, 95% confidence interval (CI) 0.8-1.4; men, 0.3%, 95% CI 0.1-0.6] to a TSH of 4.0-4.5 mU/liter (women, 31.5%, 95% CI 24.6-39.3; men, 14.7%, 95% CI 7.7-26.2). The risk of hyperthyroidism was higher in women with a baseline TSH of 0.20-0.49 mU/liter (3.9%, 95% CI 1.8-8.4) than in women with a TSH of 0.50-0.99 mU/liter (1.4%, 95% CI 0.9-2.1) or higher ( approximately 1.0%). CONCLUSION: TSH within the reference range is positively and strongly associated with the risk of future hypothyroidism. TSH at the lower limit of the reference range may be associated with an increased risk of hyperthyroidism.

Abstract: BACKGROUND: There is little knowledge about how factors early in life affect the development of migraine and tension-type headache. We aimed to examine whether growth restriction in utero is associated with development of migraine and frequent tension-type headache in adults. METHODS: The population-based Nord-Trondelag Health Study (HUNT 3) contained a validated headache questionnaire, which differentiated between migraine and tension-type headache. These data were linked to information on weight and gestational age at birth from the Norwegian Medical Birth Registry. In total 4557 females and 2789 males, aged 19-41 years, were included in this registry-based study. Participants were categorized as appropriate for gestational age (AGA, 10th-90th percentile), small for gestational age (SGA, 3rd-10th percentile) or very small for gestational age (VSGA, < 3rd percentile). Logistic regression was used to calculate odds ratios (OR) with 95% confidence intervals (CI) for migraine and tension-type headache, with exposure being growth restriction at birth. RESULTS: The effect of growth restriction on migraine was modified by sex, with a significant association in males (p<0.001), but not in females (p = 0.20). In particular, males born VSGA were at increased risk of developing migraine (OR 2.73, 95% CI 1.63-4.58, p<0.001), with an intermediate risk among those born SGA (OR 1.50, 95% CI 0.96-2.35, p = 0.08) compared to those born AGA. There was no significant association between growth restriction and frequent TTH (p = 0.051). CONCLUSION: Growth restriction was associated with increased risk of migraine in adulthood among males, but not among females. This suggests that migraine might, in part, be influenced by early life events, and that males seem to be particularly vulnerable.

Abstract: Few studies have investigated the association between serum 25-hydroxyvitamin D (25[OH]D), vitamin D supplement and asthma control among adults. We aimed to examine whether low levels of serum 25(OH)D or not taking vitamin D supplement were associated with an increased risk of poorly controlled asthma among Norwegian adults with asthma. We used a definition of asthma control adapted from the Global Initiative for Asthma. We first examined cross-sectional associations between serum 25(OH)D (n=806) or vitamin D supplement (n=1179) and poorly controlled asthma. Next, among those with well controlled asthma at baseline, we examined prospective associations between serum 25(OH)D (n=147) or vitamin D supplement (n=208) and poorly controlled asthma at follow-up, approximately 11 years later. We estimated risk ratios (RR) and 95% confidence intervals (CI) with Poisson regression. The adjusted RR for poorly controlled asthma was 1.00 (95% CI, 0.89-1.13) for adults with serum 25(OH)D<50nmol/L in cross-sectional and 1.50 (95% CI, 0.46-4.95) in prospective analyses. The adjusted RR for poorly controlled asthma was 1.17 (95% CI 1.00-1.37) for non-users of vitamin D supplement in cross-sectional and 1.66 (95% CI 0.49-5.67) in prospective analyses. Our study did not show strong evidence that among adults with asthma, having a low serum 25(OH)D or being a non-user of vitamin D supplement was associated with an increased risk of poorly controlled asthma. Some point estimates indicated an increased risk, however our estimates were generally imprecise and further evidence is needed.

Abstract: BACKGROUND: Long-term illness and work incapacity in young adulthood has consequences for both the individual and for society. The purpose of the study was to investigate the association between adolescent health and receipt of long-term sickness and disability benefits for young adults in their twenties. MATERIAL AND METHOD: An adolescent population of 8949 school students (aged 13-21 years) assessed their own health in the Young-HUNT1 Study (1995-1997). Health was measured by means of a questionnaire enquiring about chronic somatic illnesses, somatic symptoms, symptoms of anxiety and depression, sleep disturbance, poor concentration, self-reported health and smoking, and by measuring height and weight. Information about receipt of long-term benefits was retrieved from the FD-Trygd registry for the period 1998-2008 and defined as receipt of sickness benefit (>180 days/year), medical/vocational rehabilitation benefit and disability pension in the age group 20-29 years. We investigated the relationship between adolescent health and long-term social insurance benefits with logistic regression, adjusted for sex, age, follow-up time, mother's education and family composition. Siblings with different exposure and outcome were investigated to adjust for all familial factors shared by siblings. RESULTS: Each of the health measures was associated with an increased risk of long-term benefit. For example, adolescents who reported one or more somatic illnesses or poor concentration had a 5.4 and 3.4 percentage point higher risk, respectively, of receiving long-term benefits at the age of 20-29 years than adolescents who did not report somatic illness or poor concentration. Moreover the risk increased with an increase in the number of health problems. Sibling analyses supported these associations. INTERPRETATION: Health in adolescence is an indicator of increased vulnerability in the transition to the labour market. Preventing health selection during this transition should be a priority for welfare policy.

Abstract: BACKGROUND: Recent studies have shown that high levels of free thyroxine (FT4), even without leading to hyperthyroidism, are associated with a procoagulant state. OBJECTIVES: The aim of our study was to determine whether high levels of thyroid hormones are associated with an increased risk of venous thrombosis. PATIENTS/METHODS: From a prospective nested case-cohort design within the second Nord-Trondelag Health Study (HUNT2) cohort (1995-1997; 66,140 subjects), all patients with venous thrombosis during follow-up (n=515) and 1476 randomly selected age-stratified and sex-stratified controls were included. Relative and absolute risks for venous thrombosis were calculated for different cut-off levels of thyroid hormones on the basis of percentiles in the controls and different times between blood sampling and thombosis. RESULTS: In subjects with an FT4 level above the 98th percentile (17.3 pmol L(-1)), the odds ratio (OR) was 2.5 (95% confidence interval [CI] 1.3-5.0) as compared with subjects with levels below this percentile. For venous thrombosis within 1 year from blood sampling, this relative risk was more pronounced, with an OR of 4.8 (95% CI 1.7-14.0). Within 0.5 years, the association was even stronger, with an OR of 9.9 (95% CI 2.9-34.0, adjusted for age, sex, and body mass index). For thyroid-stimulating hormone, the relationship was inverse and less pronounced. The absolute risk within 6 months in the population for FT4 levels above the 98th percentile was 6.1 per 1000 person-years (95% CI 1.7-15.7). CONCLUSIONS: Levels of FT4 at the upper end of the normal range are a strong risk factor for venous thrombosis. The risk increased with higher levels of thyroxine and shorter time between blood sampling and thrombosis. Further studies on the effect of clinical hyperthyroidism are warranted.

Abstract: BACKGROUND: There has been an overall decrease in incident ischaemic heart disease (IHD), but the reduction in IHD risk factors has been greater among those with higher social position. Increased social inequalities in IHD mortality in Scandinavian countries is often referred to as the Scandinavian “public health puzzle”. The objective of this study was to examine trends in absolute and relative educational inequalities in four modifiable ischaemic heart disease risk factors (smoking, diabetes, hypertension and high total cholesterol) over the last three decades among Norwegian middle-aged women and men. METHODS: Population-based, cross-sectional data from The Nord-Trondelag Health Study (HUNT): HUNT 1 (1984-1986), HUNT 2 (1995-1997) and HUNT 3 (2006-2008), women and men 40-59 years old. Educational inequalities were assessed using the Slope Index of Inequality (SII) and The Relative Index of Inequality (RII). RESULTS: Smoking prevalence increased for all education groups among women and decreased in men. Relative and absolute educational inequalities in smoking widened in both genders, with significantly higher absolute inequalities among women than men in the two last surveys. Diabetes prevalence increased in all groups. Relative inequalities in diabetes were stable, while absolute inequalities increased both among women (p = 0.05) and among men (p = 0.01). Hypertension prevalence decreased in all groups. Relative inequalities in hypertension widened over time in both genders. However, absolute inequalities in hypertension decreased among women (p = 0.05) and were stable among men (p = 0.33). For high total cholesterol relative and absolute inequalities remained stable in both genders. CONCLUSION: Widening absolute educational inequalities in smoking and diabetes over the last three decades gives rise to concern. The mechanisms behind these results are less clear, and future studies are needed to assess if educational inequalities in secondary prevention of IHD are larger compared to educational inequalities in primary prevention of IHD. Continued monitoring of IHD risk factors at the population level is therefore warranted. The results emphasise the need for public health efforts to prevent future burdens of life-style-related diseases and to avoid further widening in socioeconomic inequalities in IHD mortality in Norway, especially among women.

Abstract: Background: Circulating concentrations of B vitamins and factors related to one-carbon metabolism have been found to be strongly inversely associated with lung cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. The extent to which these associations are present in other study populations is unknown. Methods: Within 20 prospective cohorts from the National Cancer Institute Cohort Consortium, a nested case-control study was designed including 5364 incident lung cancer case patients and 5364 control subjects who were individually matched to case patients by age, sex, cohort, and smoking status. Centralized biochemical analyses were performed to measure circulating concentrations of vitamin B6, folate, and methionine, as well as cotinine as an indicator of recent tobacco exposure. The association between these biomarkers and lung cancer risk was evaluated using conditional logistic regression models. Results: Participants with higher circulating concentrations of vitamin B6 and folate had a modestly decreased risk of lung cancer risk overall, the odds ratios when comparing the top and bottom fourths (OR 4vs1 ) being 0.88 (95% confidence interval [CI] = 0.78 to 1.00) and 0.86 (95% CI = 0.74 to 0.99), respectively. We found stronger associations among men (vitamin B6: OR 4vs1 = 0.74, 95% CI = 0.62 to 0.89; folate: OR 4vs1 = 0.75, 95% CI = 0.61 to 0.93) and ever smokers (vitamin B6: OR 4vs1 = 0.78, 95% CI = 0.67 to 0.91; folate: OR 4vs1 = 0.87, 95% CI = 0.73 to 1.03). We further noted that the association of folate was restricted to Europe/Australia and Asia, whereas no clear association was observed for the United States. Circulating concentrations of methionine were not associated with lung cancer risk overall or in important subgroups. Conclusions: Although confounding by tobacco exposure or reverse causation cannot be ruled out, these study results are compatible with a small decrease in lung cancer risk in ever smokers who avoid low concentrations of circulating folate and vitamin B6.

Abstract: Asthma, hay fever (or allergic rhinitis) and eczema (or atopic dermatitis) often coexist in the same individuals, partly because of a shared genetic origin. To identify shared risk variants, we performed a genome-wide association study (GWAS; n = 360,838) of a broad allergic disease phenotype that considers the presence of any one of these three diseases. We identified 136 independent risk variants (P < 3 x 10(-8)), including 73 not previously reported, which implicate 132 nearby genes in allergic disease pathophysiology. Disease-specific effects were detected for only six variants, confirming that most represent shared risk factors. Tissue-specific heritability and biological process enrichment analyses suggest that shared risk variants influence lymphocyte-mediated immunity. Six target genes provide an opportunity for drug repositioning, while for 36 genes CpG methylation was found to influence transcription independently of genetic effects. Asthma, hay fever and eczema partly coexist because they share many genetic risk variants that dysregulate the expression of immune-related genes.

Abstract: In previous studies on prescription patterns of opioids, accurate data on pain are missing, and previous epidemiological studies of pain lack accurate data on opioid use. The present linkage study, which investigates the relationship between pain and opioid use, is based on accurate individual data from the complete national Norwegian prescription database and the Nord-Trondelag health study 3, which includes about 46,000 people. Baseline data were collected in 2006 to 2008, and the cohort was followed up for 3 years. Of 14,477 people who reported chronic nonmalignant pain, 85% did not use opioids at all, 3% used opioids persistently, and 12% used opioids occasionally. Even in the group reporting severe or very severe chronic pain, the number not using opioids (2680) was far higher than the number who used opioids persistently (304). However, three quarters of people using opioids persistently reported strong or very strong pain in spite of the medication. Risk factors for the people with chronic pain who were not persistent opioid users at baseline to use opioids persistently 3 years later were occasional use of opioids, prescription of >100 defined daily doses per year of benzodiazepines, physical inactivity, reports of strong pain intensity, and prescription of drugs from 8 or more Anatomical Therapeutic Chemical groups. The study showed that most people having chronic nonmalignant pain are not using opioids, even if the pain is strong or very strong. However, the vast majority of patients with persistent opioid use report strong or very strong pain in spite of opioid treatment.

Abstract: We wanted to study mortality after hip fractures among elderly women in Norway. We found that excess mortality was highest short time after hip fracture, but persisted for several years after the fracture. The excess mortality was not explained by pre-fracture medical conditions. INTRODUCTION: The purpose of the present study was to investigate short and long term mortality after hip fracture, and to evaluate how comorbidity, bone mineral density, and lifestyle factors affect the survival after hip fractures. METHODS: The study cohort emerges from a population-based health survey in the county of Nord-Trondelag, Norway. Women aged 65 or more at participation at the health survey who sustained a hip fracture after attending the health survey are cases in this study (n = 781). A comparison cohort was constructed based on participants at HUNT 2 with no history of hip fractures (n = 3, 142). Kaplan-Meier survival curves were used to evaluate crude survival, and Cox regression analyses were used to study age-adjusted hazard ratios for mortality and for multivariable analyses involving relevant covariates. RESULTS: Mean length of follow-up after fracture was 2.8 years. Within the first 3 months of follow-up, 78 (10.0%) of the hip fracture patients died, compared to only 39 (1.7%) in the control group. HR for mortality 3 months after hip fracture was 6.5 (95% CI 4.2-9.6). For the entire follow-up period women who sustained a hip fracture had an HR for mortality of 1.9 (95% CI 1.6-2.3), compared with women without a hip fracture. CONCLUSIONS: We found that elderly women who sustained a hip fracture had increased mortality risk. The excess mortality was highest short time after the fracture, but persisted for several years after the fracture, and was not explained by pre-fracture medical conditions.

Abstract: BACKGROUND: Lowered physical activity levels may partially explain changes in metabolic risk factors in women after menopause. OBJECTIVES: To evaluate the association between physical activity and metabolic risk factors at baseline and after 11 years, as well as the change in that association over time in women who were premenopausal and >/= 40 years at baseline. METHODS: Subjects in a Norwegian population-based health survey answered questionnaires and had body and serum measurements during 1995-1997 (HUNT 2) and in a follow-up study during 2006-2008 (HUNT 3). Repeated-measures analyses were used to estimate the association between physical activity and metabolic factors, adjusting for age, smoking status, education, alcohol intake, and parity. Adjustment for hormonal treatment and medication was made, as appropriate. RESULTS: In women remaining premenopausal, a higher physical activity score in HUNT 3 was associated with lower weight (p < 0.01) and waist-hip ratio (p < 0.01) and higher high density lipoprotein (HDL) cholesterol in HUNT 3 (p < 0.01). In women that were postmenopausal by the time of follow-up, a higher physical activity score in HUNT 3 was associated with lower weight (p < 0.01), waist-hip ratio (p < 0.01), triglycerides (p < 0.01), and higher total cholesterol (p < 0.05), HDL cholesterol (p < 0.01), and diastolic blood pressure (p < 0.05) in HUNT 3. The association of total physical activity score with weight and waist-hip ratio was stronger in HUNT 3 than in HUNT 2 (p < 0.01). CONCLUSION: Increased physical activity may reduce the risk of adverse outcomes and use of pharmacological management in women of menopausal age.