Risk factors and prognosis for heart failure in atrial fibrillation subtypes in women and men

Background

Atrial fibrillation (AF) and heart failure (HF) are common diseases that often co-exist and substantially impact both morbidity, mortality, and quality of life. Although there has been an increasing amount of research on HF in AF patients, there is limited knowledge on the association of AF subtypes (paroxysmal/persistent, permanent) with HF in women and men.

Purpose

To explore the sex-specific association between incident AF subtypes and HF risk factors and mortality in AF participants in a general population.

Methods

A total of 14,798 women and 13,197 men aged 25 years and older were enrolled from 1994 to 2008 and followed up for incident AF and HF through 2016. Cox proportional hazards regression analysis was conducted to provide sex- and AF subtype-specific hazard ratios (HRs) for the risk of HF, risk factors for HF and joint influence on mortality when AF precedes HF. Participants without AF and HF were used as reference. In the analysis of risk factors for HF we included only those who developed AF, and the follow-up period started at the date of first detected AF. Models were adjusted for systolic blood pressure, body mass index (BMI), total cholesterol, current smoking, physical activity, and history of myocardial infarction, angina pectoris, stroke, and diabetes mellitus, as well as age, with age as the time scale in the regression models.

Results

Over a median follow-up of 21.6 years, incident AF occurred in 856 women (471 with paroxysmal/persistent AF and 385 with permanent AF) and 1,036 men (587 with paroxysmal/persistent AF and 449 with permanent AF). Incident HF occurred in 761 women and 930 men. In both sexes, there was an increased risk of HF when AF was present. For permanent AF, women had a significantly higher risk of HF than men (HR 10.50, 95% CI 8.72–12.66 vs. HR 8.11, 95% CI 6.81–9.67). Permanent AF, current smoking, and prevalent myocardial infarction were significant risk factors for HF in AF participants in both sexes, while hypertension was only associated with increased risk of HF in women and BMI and prevalent stroke in men. Higher physical activity level was associated with reduced risk of AF in both sexes. The risk of death increased when HF succeeded AF. For women the risk of mortality was higher for permanent AF (HR 3.83, 95% CI 3.19–4.61 vs. HR 2.98, 95% CI 2.34–3.80), while in men it was highest for paroxysmal/persistent AF (HR 3.67, 95% CI 2.94–4.58 vs. HR 2.91, 95% CI 2.37–3.57), but there was no significant difference between sexes.

Conclusions

All AF subtypes were associated with an increased risk of HF in both sexes. For permanent AF, women had a significantly higher risk than men. Several risk factors for HF in AF participants were similar between sexes. However, hypertension was only a risk factor in women, whereas BMI and prevalent stroke were only risk factors in men. In AF participants, subsequent development of HF was associated with increased mortality in both sexes.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): UiT The Arctic University of Norway

Macular Layer Thickness and Effect of BMI, Body Fat, and Traditional Cardiovascular Risk Factors: The Tromsø Study

Purpose

The purpose of this study was to investigate associations between cardiovascular risk factors and the thickness of retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), and outer retina layers (ORL).

Methods

In this population-based study, we included participants from the Tromsø Study: Tromsø6 (2007 to 2008) and Tromsø7 (2015 to 2016). Persons with diabetes and/or diagnosed glaucoma were excluded from this study. Retinal thickness was measured on optical coherence tomography (Cirrus HD-OCT) macula-scans, segmented on RNFL, GCIPL, and ORL and associations were analyzed cross-sectionally (N = 8288) and longitudinally (N = 2595). We used directed acyclic graphs (DAGs) for model selection, and linear regression to adjust for confounders and mediators in models assessing direct effects. Factors examined were age, sex, blood pressure, daily smoking, serum lipids, glycated hemoglobin, body mass index (BMI), total body fat percentage (BFP), and the adjustment variables refraction and height.

Results

The explained variance of cardiovascular risk factors was highest in GCIPL (0.126). GCIPL had a strong negative association with age. Women had thicker GCIPL than men at higher age and thinner ORL at all ages (P < 0.001). Systolic blood pressure was negatively associated with RNFL/GCIPL (P = 0.001/0.004), with indication of a U-shaped relationship with GCIPL in women. The negative association with BMI was strongest in men, with significant effect for RNFL/GCIPL/ORL (P = 0.001/<0.001/0.019) and in women for GCIPL/ORL (P = 0.030/0.037). BFP was negatively associated with GCIPL (P = 0.01). Higher baseline BMI was associated with a reduction in GCIPL over 8 years (P = 0.03).

Conclusions

Cardiovascular risk factors explained 12.6% of the variance in GCIPL, with weight and blood pressure the most important modifiable factors.

Association of glycated hemoglobin A1c levels with cardiovascular outcomes in the general population: results from the BiomarCaRE (Biomarker for Cardiovascular Risk Assessment in Europe) consortium

BACKGROUND

Biomarkers may contribute to improved cardiovascular risk estimation. Glycated hemoglobin A1c (HbA1c) is used to monitor the quality of diabetes treatment. Its strength of association with cardiovascular outcomes in the general population remains uncertain. This study aims to assess the association of HbA1c with cardiovascular outcomes in the general population.

METHODS

Data from six prospective population-based cohort studies across Europe comprising 36,180 participants were analyzed. HbA1c was evaluated in conjunction with classical cardiovascular risk factors (CVRFs) for association with cardiovascular mortality, cardiovascular disease (CVD) incidence, and overall mortality in subjects without diabetes (N = 32,496) and with diabetes (N = 3684).

RESULTS

Kaplan-Meier curves showed higher event rates with increasing HbA1c levels (log-rank-test: p < 0.001). Cox regression analysis revealed significant associations between HbA1c (in mmol/mol) in the total study population and the examined outcomes. Thus, a hazard ratio (HR) of 1.16 (95% confidence interval (CI) 1.02-1.31, p = 0.02) for cardiovascular mortality, 1.13 (95% CI 1.03-1.24, p = 0.01) for CVD incidence, and 1.09 (95% CI 1.02-1.17, p = 0.01) for overall mortality was observed per 10 mmol/mol increase in HbA1c. The association with CVD incidence and overall mortality was also observed in study participants without diabetes with increased HbA1c levels (HR 1.12; 95% CI 1.01-1.25, p = 0.04) and HR 1.10; 95% CI 1.01-1.20, p = 0.02) respectively. HbA1c cut-off values of 39.9 mmol/mol (5.8%), 36.6 mmol/mol (5.5%), and 38.8 mmol/mol (5.7%) for cardiovascular mortality, CVD incidence, and overall mortality, showed also an increased risk.

CONCLUSIONS

HbA1c is independently associated with cardiovascular mortality, overall mortality and cardiovascular disease in the general European population. A mostly monotonically increasing relationship was observed between HbA1c levels and outcomes. Elevated HbA1c levels were associated with cardiovascular disease incidence and overall mortality in participants without diabetes underlining the importance of HbA1c levels in the overall population.

Treatment target achievement after myocardial infarction: cardiovascular risk factors, medication use and lifestyle in Norwegian women and men

Funding Acknowledgements

Type of funding sources: None.

Background

Although the use of guidelines in clinical practice is emphasised, large multi-center studies of patients with cardiovascular disease have shown secondary prevention to be suboptimal, which increase the risk of recurrent events.

Purpose

To examine ESC guideline treatment target achievement after myocardial infarction for cardiovascular risk factors, medication use and a broad range of lifestyle factors in women and men from a Norwegian general population.

Methods

In a population-based study conducted 2015-2016 (65% attendance), 637 participants 40-95 years (23% women, 70% ≥65 years) had validated myocardial infarction. Cross-sectionally, we investigated target achievement for blood pressure (&lt;140/90 mmHg, &lt;130/80 mmHg if diabetes), LDL cholesterol (&lt;1.8 mmol/L), HbA1c (&lt;7.0% if diabetes), weight (body mass index (BMI) &lt;25 kg/m2, waist circumference (women &lt;80 cm, men &lt;94 cm)), smoking (non-smoking), physical activity (self-reported &gt;sedentary, accelerometer-measured moderate-to-vigorous ≥150 min/week), diet (intake of fruits ≥200 g/day, vegetables ≥200 g/day, fish ≥200 g/week, saturated fat &lt;10E%, fiber ≥30g/day,  and alcohol (women ≤10 g/day, men ≤20 g/day)), and medication use (antihypertensives, lipid-lowering drugs, antithrombotics, antidiabetics) using regression models.

Results

Proportion of target achievement was for blood pressure 55.8%, LDL cholesterol 9.3%, HbA1c 42.7%, BMI 19.5%, waist circumference 15.6%, non-smoking 86.2%, self-reported physical activity 79.5%, objectively measured physical activity 9.1%, intake of fruits 66.7%, vegetables 38.4%, fish 96.8%, saturated fat 25.4%, fiber 29.5%, and alcohol 78.5%, use of antidiabetics 84.3%, lipid-lowering drugs 86.8%, antihypertensives 78.5% and antithrombotics 77.9%. In total, 0.8% achieved all cardiovascular risk factor targets (blood pressure, LDL cholesterol, BMI and waist circumference combined). Compared to men, a lower proportion of women achieved the target for waist circumference (6.9% vs 18.1%, p = 0.002). Compared to participants 65 years or older, a higher proportion of those 40-64 years achieved the target for blood pressure (71.2% vs 49.0%, p &lt; 0.001), and a lower proportion achieved the target for BMI (15.3 vs 21.4, p = 0.007).

Conclusion

Secondary prevention after myocardial infarction was suboptimal in both women and men. A negligible proportion achieved the treatment target for all risk factors. Improvement in follow-up care after myocardial infarction is needed.

Neuropsychological functions of verbal recall and psychomotor speed significantly affect pain tolerance

Background

Effects from cognitive performance on pain tolerance have been documented, however, sample sizes are small and confounders often overlooked. We aimed to establish that performance on neuropsychological tests was associated with pain tolerance, controlling for salient confounders.

Methods

This was a cross‐sectional study nested within the Tromsø‐6 survey. Neuropsychological test performance and the cold pressor test were investigated in 4,623 participants. Due to significant interaction with age, participants were divided into three age groups (<60, ≥60 to <70 and ≥70 years). Cox proportional hazard models assessed the relationship between neuropsychological tests and cold pressure pain tolerance, using hand‐withdrawal as event. The fully adjusted models controlled for sex, education, BMI, smoking status, exercise, systolic blood pressure, sleep problems and mental distress.

Results

In the adjusted models, participants aged ≥70 years showed a decreased hazard of hand withdrawal of 18% (HR 0.82, 95% CI (0.73, 0.92) per standard deviation on immediate verbal recall, and a decreased hazard of 23% (HR 0.77, 95% CI (0.65, 0.08) per standard deviation on psychomotor speed. Participants aged ≥60 to <70 years had a significant decreased hazard of 11% (HR 0.89, 95% CI (0.80, 0.98) per standard deviation on immediate word recall. In participants aged <60 years, there was a decreased hazard of 14% (HR 0.86 95% CI: 0.76, 0.98), per standard deviation on psychomotor speed.

Conclusion

Better performance on neuropsychological tests increased pain tolerance on the cold pressor test. These exposure effects were present in all age groups.

Significance

This paper describes substantial associations between cognitive functioning and cold pressor tolerance in 4,623 participants. Reduced psychomotor speed and poor verbal recall gave greater odds for hand‐withdrawal on the cold pressor task. The associations were stronger in older participants, indicating an interaction with age.

The impact of risk factor trends on intracerebral hemorrhage incidence over the last two decades—The Tromsø Study

Background

Studies on the relationship between temporal trends in risk factors and incidence rates of intracerebral hemorrhage are scarce.

Aims

To analyze temporal trends in risk factors and incidence rates of intracerebral hemorrhage using individual data from a population-based study.

Methods

We included 28,167 participants of the Tromsø Study enrolled between 1994 and 2008. First-ever intracerebral hemorrhages were registered through 31 December 2013. Hazard ratios (HRs) for intracerebral hemorrhage were analyzed by Cox proportional hazards models, risk factor levels over time by generalized estimating equations, and incidence rate ratios (IRR) by Poisson regression.

Results

We registered 219 intracerebral hemorrhages. Age, male sex, systolic blood pressure (BP), diastolic BP, and hypertension were associated with intracerebral hemorrhage. Hypertension was more strongly associated with non-lobar intracerebral hemorrhage (HR 5.08, 95% CI 2.86–9.01) than lobar intracerebral hemorrhage (HR 1.91, 95% CI 1.12–3.25). In women, incidence decreased significantly (IRR 0.46, 95% CI 0.23–0.90), driven by a decrease in non-lobar intracerebral hemorrhage. Incidence rates in men remained stable (IRR 1.27, 95% CI 0.69–2.31). BP levels were lower and decreased more steeply in women than in men. The majority with hypertension were untreated, and a high proportion of those treated did not reach treatment goals.

Conclusions

We observed a significant decrease in intracerebral hemorrhage incidence in women, but not in men. A steeper BP decrease in women may have contributed to the diverging trends. The high proportion of untreated and sub-optimally treated hypertension calls for improved strategies for prevention of intracerebral hemorrhage.

Repeated measurements of carotid atherosclerosis and future risk of venous thromboembolism: the Tromsø Study

Essentials The relationship between atherosclerosis and venous thromboembolism (VTE) is controversial. In total, 10 426 participants recruited from the general population were included. Carotid intima media thickness and total plaque area was not associated with VTE. There was no association between plaque initiation or plaque progression and subsequent VTE.

SUMMARY

Background Whether a relationship between atherosclerosis and subsequent venous thromboembolism (VTE) exists is controversial. Objective To investigate the association between carotid atherosclerosis and VTE by using repeated measurements of intima media thickness (IMT) and total plaque area (TPA) in participants recruited from the general population. Methods Participants were recruited from the fourth (1994-1995), fifth (2001-2002) and sixth (2007-2008) surveys of the Tromsø Study. In total, 10 426 participants attended, for whom measurements of carotid IMT and TPA and potential confounders were updated at each available survey. Time-varying Cox regression models were used to calculate hazard ratios (HRs) of VTE across various levels of IMT and TPA adjusted for age, sex, and body mass index. Results There were 368 incident VTE events during a median follow-up of 10.8 years. Participants with increasing IMT were, on average, older and had a less favorable cardiovascular risk profile. There was no association between tertiles of increasing TPA and the risk of VTE in the time-varying model, and increasing IMT was not associated with an increased risk of VTE (HR 0.96, 95% confidence interval [CI] 0.86-1.07). Neither plaque formation nor plaque progression was associated with the risk of VTE (respectively: HR 1.00, 95% CI 0.98-1.02; and HR 0.96, 95% CI 0.84-1.11). Conclusion Carotid IMT and TPA were not associated with an increased risk of VTE in time-varying analyses. Furthermore, there was no association between plaque initiation or plaque progression and subsequent VTE.

Impact of Venous Thromboembolism on the Formation and Progression of Carotid Atherosclerosis: The Tromsø Study

Venous thromboembolism (VTE) is associated with increased risk of arterial cardiovascular diseases (CVD), and development of atherosclerosis secondary to VTE may be an intermediate between VTE and CVD. Therefore, we aimed to investigate whether incident VTE was associated with subsequent carotid atherosclerosis formation and progression in a population-based observational study. Subjects attending two or more ultrasound examinations of the right carotid artery, with measurement of total plaque area (TPA), in the Tromsø Study in 1994–1995, 2001–2002, and/or 2007–2008 were eligible. We identified 150 subjects diagnosed with first-lifetime VTE between the initial and follow-up visit, and randomly selected 600 age- and sex-matched subjects without VTE between the visits. Subjects with VTE and carotid plaque(s) at the first visit had 4.1 mm ² (β: 4.13, 95% CI: −1.72 to 9.98) larger change in TPA between the first and second visit compared with subjects without VTE after adjustment for change in high-sensitivity C-reactive protein (hs-CRP) and traditional atherosclerotic risk factors. The association remained after restricting the analyses to VTE events diagnosed in the first half of the time interval between the carotid ultrasounds (β: 4.02, 95% CI: −3.66 to 11.70), supporting that the change in TPA occurred subsequent to the VTE. No association was found between VTE and novel carotid plaque formation. In conclusion, we found a possible association between VTE and atherosclerosis progression in those with already established carotid plaques, but not between VTE and novel plaque formation. The association between VTE and carotid plaque progression was not mediated by low-grade inflammation assessed by hs-CRP.

Temporal Trends in Incidence and Case Fatality of Intracerebral Hemorrhage: The Tromsø Study 1995-2012

Background

The aim of this study was to explore temporal trends in incidence and case fatality rates of intracerebral hemorrhage (ICH) over the last two decades in a Norwegian municipality.

Methods

Incident cases of primary ICH were registered in the period from 1995 through 2012 in 32,530 participants of the longitudinal population-based Tromsø Study. Poisson regression models were used to obtain incidence rates over time in age- and sex-adjusted and age- and sex-specific models. Case fatality rates were calculated and age- and sex-adjusted trends over time were estimated using logistic regression.

Results

A total of 226 ICHs were registered. The age- and sex-adjusted incidence rate [95% confidence interval (CI)] in the overall population was 0.42 (0.37-0.48) per 1,000 person-years. Age-adjusted incidence rates were 0.53 (0.43-0.62) in men and 0.33 (0.26-0.39) in women. In individuals aged <75 years, the age- and sex-adjusted incidence rate was 0.27 (0.22-0.32) and in individuals aged ≥75 years, it was 2.42 (1.95-2.89) per 1,000 person-years. There was no significant change in incidence rates over time. The incidence rate ratio (95% CI) in the overall population was 0.73 (0.47-1.12) in 2012 compared with 1995. The overall 30-day case fatality (95% CI) was 23.9% (18.3-29.5) and did not change substantially over time [odds ratio in 2012 vs. 1995 = 0.83 (95% CI 0.27-2.52)].

Conclusion

No significant changes in incidence and case fatality rates of ICH were observed during the last two decades.

C-reactive protein, obesity, and the risk of arterial and venous thrombosis

Essentials We performed repeated measurements of C-reactive protein (CRP) and obesity in a cohort study. CRP was associated with risk of myocardial infarction and venous thromboembolism. CRP was a mediator for risk of myocardial infarction in obese men and women. CRP was a partial mediator for risk of venous thromboembolism in obese women, but not in men.

SUMMARY

Background Low-grade inflammation in obesity may be a shared pathway for the risk of venous thromboembolism (VTE) and myocardial infarction (MI). Objectives To investigate the associations between repeated measurements of C-reactive protein (CRP) and the risks of MI and VTE, and to explore whether CRP mediated these risks in obese subjects. Methods CRP and obesity measures were collected from 15 134 subjects who participated in one or more surveys of the Tromsø study in 1994-1995, 2001-2002, or 2007-2008. Incident VTEs and MIs were registered until 1 January 2011. Time-varying Cox regression models were used to calculate hazard ratios of MI and VTE according to categories of CRP and obesity measures. Results There were 291 VTEs and 920 MIs during follow-up. High levels of CRP (≥ 3 mg L(-1) versus < 1 mg L(-1) ) were associated with increased risks of MI (hazard ratio [HR] 1.73; 95% confidence interval [CI] 1.32-2.26) and VTE (HR 1.84; 95% CI 1.22-2.78) in women, but only with MI in men (HR 1.93; 95% CI 1.53-2.44). All obesity measures showed stronger associations with CRP in women than in men. In obese women (body mass index [BMI] of ≥ 30 kg m(-2) versus < 25 kg m(-2) ), adjustment for CRP attenuated the risk estimate for VTE by 22%, whereas the incidence rates of VTE increased with combined categories of higher BMI and CRP. No association was found in men. Conclusions Our findings suggest that low-grade inflammation, assessed by measurement of CRP, is associated with the risks of MI and VTE, and may be a shared pathway for MI and VTE in obesity.

Impact of incident myocardial infarction on the risk of venous thromboembolism: the Tromsø Study

Essentials Registry-based studies indicate a link between arterial- and venous thromboembolism (VTE). We studied this association in a cohort with confounder information and validated outcomes. Myocardial infarction (MI) was associated with a 4.8-fold increased short-term risk of VTE. MI was associated with a transient increased risk of VTE, and pulmonary embolism in particular.

SUMMARY

Background Recent studies have demonstrated an association between venous thromboembolism (VTE) and arterial thrombotic diseases. Objectives To study the association between incident myocardial infarction (MI) and VTE in a prospective population-based cohort. Methods Study participants (n = 29 506) were recruited from three surveys of the Tromsø Study (conducted in 1994-1995, 2001-2002, and 2007-2008) and followed up to 2010. All incident MI and VTE events during follow-up were recorded. Cox regression models with age as the time scale and MI as a time-dependent variable were used to calculate hazard ratios (HRs) of VTE adjusted for sex, body mass index, blood pressure, diabetes mellitus, HDL cholesterol, smoking, physical activity, and education level. Results During a median follow-up of 15.7 years, 1853 participants experienced an MI and 699 experienced a VTE. MI was associated with a 51% increased risk of VTE (HR 1.51; 95% confidence interval [CI] 1.08-2.10) and a 72% increased risk of pulmonary embolism (PE) (HR 1.72; 95% CI 1.07-2.75), but not significantly associated with the risk of deep vein thrombosis (DVT) (HR 1.36; 95% CI 0.86-2.15). The highest risk estimates for PE were observed during the first 6 months after the MI (HR 8.49; 95% CI 4.00-18.77). MI explained 6.2% of the PEs in the population (population attributable risk) and 78.5% of the PE risk in MI patients (attributable risk). Conclusions Our findings indicate that MI is associated with a transient increased VTE risk, independently of traditional atherosclerotic risk factors. The risk estimates were particularly high for PE.

HbA1c levels in non-diabetic older adults - No J-shaped associations with primary cardiovascular events, cardiovascular and all-cause mortality after adjustment for confounders in a meta-analysis of individual participant data from six cohort studies

BACKGROUND

To determine the shape of the associations of HbA1c with mortality and cardiovascular outcomes in non-diabetic individuals and explore potential explanations.

METHODS

The associations of HbA1c with all-cause mortality, cardiovascular mortality and primary cardiovascular events (myocardial infarction or stroke) were assessed in non-diabetic subjects ≥50 years from six population-based cohort studies from Europe and the USA and meta-analyzed. Very low, low, intermediate and increased HbA1c were defined as <5.0, 5.0 to <5.5, 5.5 to <6.0 and 6.0 to <6.5% (equals <31, 31 to <37, 37 to <42 and 42 to <48 mmol/mol), respectively, and low HbA1c was used as reference in Cox proportional hazards models.

RESULTS

Overall, 6,769 of 28,681 study participants died during a mean follow-up of 10.7 years, of whom 2,648 died of cardiovascular disease. Furthermore, 2,493 experienced a primary cardiovascular event. A linear association with primary cardiovascular events was observed. Adjustment for cardiovascular risk factors explained about 50% of the excess risk and attenuated hazard ratios (95 confidence interval) for increased HbA1c to 1.14 (1.03-1.27), 1.17 (1.00-1.37) and 1.19 (1.04-1.37) for all-cause mortality, cardiovascular mortality and cardiovascular events, respectively. The six cohorts yielded inconsistent results for the association of very low HbA1c levels with the mortality outcomes and the pooled effect estimates were not statistically significant. In one cohort with a pronounced J-shaped association of HbA1c levels with all-cause and cardiovascular mortality (NHANES), the following confounders of the association of very low HbA1c levels with mortality outcomes were identified: race/ethnicity; alcohol consumption; BMI; as well as biomarkers of iron deficiency anemia and liver function. Associations for very low HbA1c levels lost statistical significance in this cohort after adjusting for these confounders.

CONCLUSIONS

A linear association of HbA1c levels with primary cardiovascular events was observed. For cardiovascular and all-cause mortality, the observed small effect sizes at both the lower and upper end of HbA1c distribution do not support the notion of a J-shaped association of HbA1c levels because a certain degree of residual confounding needs to be considered in the interpretation of the results.

Genetic Variations in the Vitamin D Receptor Predict Type 2 Diabetes and Myocardial Infarction in a Community-Based Population: The Tromsø Study

BACKGROUND

Though the associations between low serum 25-hydroxyvitamin D (25(OH)D) levels and health outcomes such as type 2 diabetes (T2D), myocardial infarction (MI), cancer, and mortality are well-studied, the effect of supplementation with vitamin D is uncertain. This may be related to genetic differences. Thus, rs7968585, a single nucleotide polymorphism (SNP) of the vitamin D receptor (VDR), has recently been reported as a predictor of composite health outcome. We therefore aimed to evaluate whether rs7968585 predicts separate clinical outcomes such as T2D, MI, cancer, and mortality in a community-based Norwegian population.

METHODS AND FINDINGS

Measurements and DNA were obtained from the participants in the Tromsø Study in 1994-1995, registered with the outcomes of interest and a randomly selected control group. The impact of the rs7968585 genotypes was evaluated with Cox proportional hazards. A total of 8,461 subjects were included among whom 1,054 subjects were registered with T2D, 2,287 with MI, 3,166 with cancer, and 4,336 with death. Mean follow-up time from birth was 60.8 years for T2D and MI, 61.2 years for cancer, while mean follow-up time from examination date was 16.5 years for survival. Mean serum 25(OH)D levels did not differ across the rs7968585 genotypes. With the major homozygote genotype as reference, the minor homozygote subjects had hazard ratios of 1.25 (95% CI 1.05-1.49) for T2D and 1.14 (1.02-1.28) for MI (P = 0.011 and 0.023, respectively, without the Bonferroni correction). No significant interaction between serum 25(OH)D status and the rs7968585 genotype was found for any of the endpoints.

CONCLUSIONS

The VDR-related SNP rs7968585 minor allele is a significant and positive predictor for T2D and possibly for MI. Since the functional mechanism of this SNP is not yet understood, and the association with T2D is reported for the first time, confirmatory studies are needed.

Clinically significant novel biomarkers for prediction of first ever myocardial infarction: the Tromsø Study

BACKGROUND

Identification of individuals with high risk for first-ever myocardial infarction (MI) can be improved. The objectives of the study were to survey multiple protein biomarkers for association with the 10-year risk of incident MI and identify a clinically significant risk model that adds information to current common risk models.

METHODS AND RESULTS

We used an immunoassay platform that uses a sensitive, sample-efficient molecular counting technology to measure 51 proteins in samples from the fourth survey (1994) in the Tromsø Study, a longitudinal study of men and women in Tromsø, Norway. A case control design was used with 419 first-ever MI cases (169 females/250 males) and 398 controls (244 females/154 males). Of the proteins measured, 17 were predictors of MI when considered individually after adjustment for traditional risk factors either in men, women, or both. The 6 biomarkers adjusted for traditional risk factors that were selected in a multivariable model (odds ratios [OR] per standard deviation) using a stepwise procedure were apolipoprotein B/apolipoprotein A1 ratio (1.40), kallikrein (0.73), lipoprotein a (1.29), matrix metalloproteinase 9 (1.30), the interaction term IP-10/CXCL10×women (0.69), and the interaction term thrombospondin 4×men (1.38). The composite risk of these biomarkers added significantly to the traditional risk factor model with a net reclassification improvement of 14% (P=0.0002), whereas the receiver operating characteristic area increased from 0.757 to 0.791, P=0.0004.

CONCLUSIONS

Novel protein biomarker models improve identification of 10-year MI risk above and beyond traditional risk factors with 14% better allocation to either high or low risk group.

Atrial fibrillation and future risk of venous thromboembolism:the Tromsø study

AIMS

Whether atrial fibrillation is related to risk of venous thromboembolism (VTE) has not been extensively studied. Therefore, we investigated the association between atrial fibrillation and future risk of VTE in a population-based cohort.

METHODS

In total, 29,975 subjects were recruited from three surveys of the Tromsø study and followed from enrollment (1994-1995, 2001-2002 and 2007-2008) up to 2010. Incident events of atrial fibrillation and VTE during follow-up were recorded. Information on potential confounders was obtained at baseline. Cox-regression models with atrial fibrillation as time-dependent variable were used to calculate hazard ratios (HRs) for VTE with 95% confidence intervals (CIs).

RESULTS

During 16 years of median follow-up, 1604 subjects were diagnosed with atrial fibrillation and 614 with incident VTE. The risk of VTE was substantially increased during the first 6 months after diagnosis of atrial fibrillation (HR, 8.44; 95% CI, 5.61-12.69), and remained increased throughout the study period (HR, 1.43; 95% CI, 1.43-1.99) compared with those without atrial fibrillation. Atrial fibrillation displayed higher risk estimates for pulmonary embolism (HR, 11.84; 95% CI, 6.80-20.63) than for deep vein thrombosis (HR, 6.20; 95% CI, 3.37-11.39) during the first 6 months, and was still associated with pulmonary embolism (HR, 1.96; 95% CI, 1.24-3.10) but not with deep vein thrombosis (HR, 1.08; 95% CI, 0.66-1.75) more than 6 months after diagnosis.

CONCLUSION

Atrial fibrillation was associated with increased risk of VTE, and pulmonary embolism in particular. Our findings support the concept that isolated pulmonary embolism may originate from right atrial thrombi due to atrial fibrillation.

Vitamin D and mortality: meta-analysis of individual participant data from a large consortium of cohort studies from Europe and the United States

OBJECTIVE

To investigate the association between serum 25-hydroxyvitamin D concentrations (25(OH)D) and mortality in a large consortium of cohort studies paying particular attention to potential age, sex, season, and country differences.

DESIGN

Meta-analysis of individual participant data of eight prospective cohort studies from Europe and the US.

SETTING

General population.

PARTICIPANTS

26,018 men and women aged 50-79 years.

MAIN OUTCOME MEASURES

All-cause, cardiovascular, and cancer mortality.

RESULTS

25(OH)D concentrations varied strongly by season (higher in summer), country (higher in US and northern Europe) and sex (higher in men), but no consistent trend with age was observed. During follow-up, 6695 study participants died, among whom 2624 died of cardiovascular diseases and 2227 died of cancer. For each cohort and analysis, 25(OH)D quintiles were defined with cohort and subgroup specific cut-off values. Comparing bottom versus top quintiles resulted in a pooled risk ratio of 1.57 (95% CI 1.36 to 1.81) for all-cause mortality. Risk ratios for cardiovascular mortality were similar in magnitude to that for all-cause mortality in subjects both with and without a history of cardiovascular disease at baseline. With respect to cancer mortality, an association was only observed among subjects with a history of cancer (risk ratio, 1.70 (1.00 to 2.88)). Analyses using all quintiles suggest curvilinear, inverse, dose-response curves for the aforementioned relationships. No strong age, sex, season, or country specific differences were detected. Heterogeneity was low in most meta-analyses.

CONCLUSIONS

Despite levels of 25(OH)D strongly varying with country, sex, and season, the association between 25(OH)D level and all-cause and cause-specific mortality was remarkably consistent. Results from a long term randomised controlled trial addressing longevity are being awaited before vitamin D supplementation can be recommended in most individuals with low 25(OH)D levels.

The phosphodiesterase 8B gene rs4704397 is associated with thyroid function, risk of myocardial infarction, and body height: the Tromsø study

OBJECTIVE

High serum thyrotropin (TSH) levels predict cardiovascular disease (CVD). Recently several single nucleotide polymorphisms (SNPs) associated with TSH levels have been identified, one of them being the rs4704397 SNP in the phosphodiesterase 8B (PDE8B) gene. If the relation between thyroid function and CVD is causal, one could also expect rs4704397 genotypes to predict CVD and possibly health in general.

METHODS

DNA was prepared and genotyping performed for rs4704397 in subjects who participated in the fourth survey of the Tromsø Study in 1994-1995 and who were registered with the endpoints myocardial infarction (MI), type 2 diabetes (T2DM), cancer, or death, as well as a randomly selected control group. Similarly, genotyping was performed in subjects who had participated in clinical trials where serum TSH, free T4 (fT4), and free T3 (fT3) were measured.

RESULTS

From the Tromsø Study, 8938 subjects without thyroid disease or thyroid medication were successfully genotyped for rs4704397. Among these, 2098 were registered with MI, 1025 with T2DM, 2748 with cancer, and 3592 had died. The minor homozygote genotype (A:A) had a median serum TSH level that was 0.29 mIU/L higher than in the major homozygote genotype (G:G). The A:A genotype had a significantly increased risk of MI as compared to the G:G genotype (1.14 [1.00-1.29], hazard ratio [confidence interval], Cox regression with adjustment for age, sex, and body mass index). No significant associations were seen with the other endpoints or CVD risk factors. Furthermore, subjects with the G:G genotype were significantly taller than subjects with the A:A genotype (mean difference 1.5 cm). In 584 subjects with serum TSH, fT4, and fT3 measurements, the subjects with the A:A genotype had significantly higher serum TSH and nonsignificantly lower serum fT3 (mean difference 0.15 pmol/L) levels than subjects with the G:G genotype.

CONCLUSION

rs4704397 is associated with thyroid function, risk of MI, and body height. However, confirmation in other cohorts is needed before firm conclusions can be drawn.

Single-nucleotide polymorphism, rs1799941 in the Sex Hormone-Binding Globulin (SHBG) gene, related to both serum testosterone and SHBG levels and the risk of myocardial infarction, type 2 diabetes, cancer and mortality in men: the Tromsø Study

Low testosterone levels are associated with metabolic and cardiovascular disease risk factor, and have been shown to predict type 2 diabetes mellitus (T2DM), myocardial infarction (MI) and all-cause mortality. It is not known if these associations are causal or not. Recently, it has been shown that the serum testosterone levels are associated with single-nucleotide polymorphisms (SNPs), and we therefore studied the associations between one of these SNPs, rs1799941 on the Sex Hormone-Binding Globulin (SHBG) gene, and MI, T2DM, cancer and death. DNA was prepared from men who participated in the fourth survey of the Tromsø Study in 1994-1995 and who were registered with the endpoints MI, T2DM, cancer or death and a randomly selected control group. For mortality, the observation time was set from 1994, and for the other endpoints from birth. The endpoint data were completed up to 2010-2013. Genetic analyses were successfully performed in 5309 men, of whom 1454 were registered with MI, 638 with T2DM, 1534 with cancer and in 2226 who had died. Men with the minor homozygote genotype had significantly higher levels of total testosterone (14.7%) and SHBG (24.7%) compared with men with the major homozygote genotype, whereas free testosterone levels did not differ significantly between the genotypes. The SNP rs1799941 was not significantly associated with MI, T2DM, cancer or mortality. Thus, our result does not support a causal relationship between total testosterone and SHBG and MI, T2DM, cancer or mortality, suggesting that low testosterone more likely is a marker of poor health.

Cognitive function, drusen, and age-related macular degeneration: a cross-sectional study

PURPOSE

To examine the cross-sectional relationship between drusen, late age-related macular degeneration (AMD), and cognitive function. METHODS; We included 2149 stroke-free participants from the population-based Tromsø Study in Norway. Retinal photographs were graded for presence of drusen and AMD. Cognitive function was assessed using the verbal memory test (short verbal memory), digit-symbol coding test (processing speed), and the tapping test (psychomotor tempo). We assessed the relationship between drusen, late AMD, and cognitive test scores, adjusted for potential confounders.

RESULTS

Late AMD was associated with decreased performance in the verbal memory test (standardized β=-0.23, 95% confidence interval (CI): -0.51 to -0.01). Intermediate and large drusen were associated with decreased performance in the digit-symbol coding test (standardized β=-0.14 and -0.19, 95% CIs: -0.23 to -0.05 and -0.29 to -0.09, respectively). Participants with large drusen were more likely to have test scores in the lowest quartile of the digit-symbol coding test (odds ratio (OR)=1.9, 95% CI: 1.1-3.5) and the tapping test (OR=1.6, 95% CI: 1.0-2.6), but not in the verbal memory test (OR=1.0, 95% CI: 0.6-1.6).

CONCLUSIONS

The findings suggest a relationship between drusen deposition and reduced cognitive function. Although the relationships between drusen, late AMD, and the cognitive test results varied in strength and significance across the types of cognitive test, and may partly have been caused by residual confounding, it is not unlikely that a genuine but weaker relationship exists between drusen deposition and cognitive decline.

Common carotid intima-media thickness does not add to Framingham risk score in individuals with diabetes mellitus: the USE-IMT initiative

AIMS/HYPOTHESIS

The aim of this work was to investigate whether measurement of the mean common carotid intima-media thickness (CIMT) improves cardiovascular risk prediction in individuals with diabetes.

METHODS

We performed a subanalysis among 4,220 individuals with diabetes in a large ongoing individual participant data meta-analysis involving 56,194 subjects from 17 population-based cohorts worldwide. We first refitted the risk factors of the Framingham heart risk score on the individuals without previous cardiovascular disease (baseline model) and then expanded this model with the mean common CIMT (CIMT model). The absolute 10 year risk for developing a myocardial infarction or stroke was estimated from both models. In individuals with diabetes we compared discrimination and calibration of the two models. Reclassification of individuals with diabetes was based on allocation to another cardiovascular risk category when mean common CIMT was added.

RESULTS

During a median follow-up of 8.7 years, 684 first-time cardiovascular events occurred among the population with diabetes. The C statistic was 0.67 for the Framingham model and 0.68 for the CIMT model. The absolute 10 year risk for developing a myocardial infarction or stroke was 16% in both models. There was no net reclassification improvement with the addition of mean common CIMT (1.7%; 95% CI -1.8, 3.8). There were no differences in the results between men and women.

CONCLUSIONS/INTERPRETATION

There is no improvement in risk prediction in individuals with diabetes when measurement of the mean common CIMT is added to the Framingham risk score. Therefore, this measurement is not recommended for improving individual cardiovascular risk stratification in individuals with diabetes.

Risk factors for aneurysmal subarachnoid hemorrhage - BMI and serum lipids: 11-year follow-up of the HUNT and the Tromsø Study in Norway

OBJECTIVES

Life-style factors have been associated with the risk for aneurysmal subarachnoid hemorrhage (aSAH), but it is not clear whether body mass index (BMI) and serum lipids are associated with risk. We prospectively assessed these associations in two large population studies.

METHODS

A total of 65,526 participants in the Nord-Trøndelag Health Study (1995-1997) and 26,882 participants in the Tromsø Study (1994-1995) were included. Studies included measurements of body weight and height, serum lipids, and self-administered questionnaires. Participants who experienced aSAH were identified, and hazard ratios (HRs) were estimated using Cox regression analysis.

RESULTS

During 11 years of follow-up, aSAH was diagnosed in 122 participants. Overweight (BMI 25-29.9) was negatively associated with the risk of aSAH (HR 0.7, 95% CI 0.4-1.0). There was no over all association of total serum cholesterol, HDL cholesterol, or triglycerides with the risk of aSAH, but in participants younger than 50 years, HDL cholesterol was inversely associated with the risk (HR per standard deviation increase 0.6, 95% CI 0.4-0.9).

CONCLUSIONS

Overweight may be associated with reduced risk of aSAH, but there was no over all association of total serum cholesterol, HDL cholesterol, or triglycerides with the risk of aSAH in this prospective study.

Polymorphisms related to the serum 25-hydroxyvitamin D level and risk of myocardial infarction, diabetes, cancer and mortality. The Tromsø Study

OBJECTIVE

Low serum 25(OH)D levels are associated with cardiovascular risk factors, and also predict future myocardial infarction (MI), type 2 diabetes (T2DM), cancer and all-cause mortality. Recently several single nucleotide polymorphisms (SNPs) associated with serum 25-hydroxyvitamin D (25(OH)D) level have been identified. If these relations are causal one would expect a similar association between these SNPs and health.

METHODS

DNA was prepared from subjects who participated in the fourth survey of the Tromsø Study in 1994-1995 and who were registered with the endpoints MI, T2DM, cancer or death as well as a randomly selected control group. The endpoint registers were complete up to 2007-2010. Genotyping was performed for 17 SNPs related to the serum 25(OH)D level.

RESULTS

A total of 9528 subjects were selected for genetic analyses which were successfully performed for at least one SNP in 9471 subjects. Among these, 2025 were registered with MI, 1092 with T2DM, 2924 with cancer and 3828 had died. The mean differences in serum 25(OH)D levels between SNP genotypes with the lowest and highest serum 25(OH)D levels varied from 0.1 to 7.8 nmol/L. A genotype score based on weighted risk alleles regarding low serum 25(OH)D levels was established. There was no consistent association between the genotype score or individuals SNPs and MI, T2DM, cancer, mortality or risk factors for disease. However, for rs6013897 genotypes (located at the 24-hydroxylase gene (CYP24A1)) there was a significant association with breast cancer (P<0.05).

CONCLUSION

Our results do not support nor exclude a causal relationship between serum 25(OH)D levels and MI, T2DM, cancer or mortality, and our observation on breast cancer needs confirmation. Further genetic studies are warranted, particularly in populations with vitamin D deficiency.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01395303.

Carotid artery plaque progression and cognitive decline: the Tromsø Study 1994-2008

BACKGROUND

Carotid atherosclerosis is a risk factor for stroke and cognitive decline, but knowledge on how progression of carotid atherosclerosis affects cognitive function in stroke-free individuals is scarce.

METHODS

In the population-based Tromsø study, we calculated the change in ultrasound-assessed carotid plaque number and total plaque area from baseline (survey 4) to follow-up 7 years later (survey 5) in 4274 middle-aged stroke-free subjects. Cognitive function was assessed at follow-up by the verbal memory test, the digit-symbol coding test, and the tapping test and repeated after an additional 6 years in a subgroup of 2042 subjects (survey 6). Associations between the average of survey 4 and survey 5 plaque scores and the progression of plaque scores and cognitive test scores were assessed in regression analyses adjusted for baseline age, sex, education, depression, and cardiovascular risk factors.

RESULTS

Progression of total plaque area was associated with lower scores in the digit-symbol coding test (multivariable adjusted standardized β, -0.03; 95% CI, -0.05 to -0.00; P = 0.04) and the tapping test (β, -0.03; 95% CI, -0.06 to -0.00; P = 0.03). Similar results were seen for progression of plaque number. The average plaque scores were associated with lower scores in all cognitive tests (P-values ≤ 0.01). No association was found between plaque scores and cognitive decline.

CONCLUSIONS

The average plaque scores were associated with lower scores in all cognitive tests. Progression of plaque scores was associated with lower scores in the digit-symbol coding test and the tapping test, but not with the verbal memory test or with cognitive decline.

Subclinical carotid atherosclerosis and cognitive function

Carotid artery atherosclerosis is a major risk factor for stroke and subsequent cognitive impairment. Recent studies indicate that carotid atherosclerosis without clinical stroke may also be an independent risk factor for cognitive decline and dementia. Ultrasonography is an easily assessable and non-invasive method to measure different stages of the carotid artery atherosclerotic process and is widely used in clinical assessment as well as in epidemiological and clinical research. We give a brief review of studies that have investigated degrees of the subclinical atherosclerosis in the carotid arteries in relation to cognitive function and dementia, and we discuss several possible mechanisms that could explain the association between atherosclerosis and cognitive impairment.

Incidence and mortality of aneurysmal subarachnoid hemorrhage in two Norwegian cohorts, 1984-2007

OBJECTIVE

The incidence of aneurysmal subarachnoid hemorrhage (aSAH) ranges from 4 to 10 per 100,000 person-years in most countries, and 30-day case fatality is high. The aim of this study was to estimate the incidence and case fatality of aSAH and to assess preictal predictors of survival in 2 large Norwegian population-based cohort studies.

METHODS

A total of 94,976 adults (≥20 years) in the Nord-Trøndelag Health Study and 31,753 participants (aged ≥20 years) in the Tromsø Study were included. During follow-up, aSAHs were identified, incidence rates were estimated, and predictors of survival were assessed using Cox and Poisson regression analysis.

RESULTS

A total of 214 patients with aSAH were identified during 2,077,927 person-years of follow-up from 1984 to 2007. The incidence rate was 10.3 per 100,000 person-years: 13.3 for women and 7.1 for men. The incidence increased by 2% (95% confidence interval [CI] 0-4) per 5-year time period. Case fatality at 3, 7, and 30 days was 20%, 24%, and 36%. Thirty-day case fatality remained stable during follow-up (odds ratio 1.01, 95% CI 0.97-1.06 per year). Never smokers had poorer survival after aSAH than current and former smokers combined (hazard ratio 1.6, 95% CI 0.9-2.9).

CONCLUSIONS

The slight increase in incidence of aSAH over time may be explained by differences in diagnostic procedures. Case fatality remained stable during 23 years of follow-up.

Serum osteoprotegerin is a predictor for incident cardiovascular disease and mortality in a general population: the Tromsø Study

BACKGROUND

Osteoprotegerin (OPG) concentration in serum is associated with the presence and severity of atherosclerosis.

OBJECTIVE

To investigate the association between serum osteoprotegerin and the risk of a future myocardial infarction, ischemic stroke and mortality in a general population.

PATIENTS/METHODS

OPG was measured in serum collected from 6265 subjects recruited from a general population without a prior myocardial infarction and ischemic stroke (the Tromsø Study). Incident myocardial infarction, ischemic stroke and mortality were registered during follow-up. Cox regression models were used to estimate crude and adjusted hazard ratios and 95% confidence intervals (HR; 95% CI).

RESULTS

There were 575 myocardial infarctions, 284 ischemic strokes and 824 deaths (146 deaths as a result of ischemic heart disease, 78 deaths because of stroke and 600 deaths due to other causes) in the cohort during a median of 10.6 years of follow-up. Serum OPG (per SD [1.13 ng mL(-1)] increase in OPG) was associated with an increased risk of a myocardial infarction (1.20; 1.11-1.31), ischemic stroke (1.32; 1.18-1.47), total mortality (1.34; 1.26-1.42), death because of ischemic heart disease, (1.35; 1.18-1.54), stroke (1.44; 1.19-1.75) and non-vascular causes (1.31; 1.22-1.41) after adjustment for age, gender, current smoking, systolic blood pressure, body mass index, high density lipoprotein cholesterol, total cholesterol, creatinine, high sensitivity C-reactive protein (CRP) and diabetes mellitus or HbA1c > 6.1%. No association was detected between OPG and incident hemorrhagic stroke (1.02; 0.73-1.43).

CONCLUSIONS

Serum OPG was associated with future risk of myocardial infarction, ischemic stroke, total mortality, mortality of ischemic heart disease, stroke and of non-vascular causes independent of traditional cardiovascular risk factors.

Moderate wine consumption is associated with better cognitive test results: a 7 year follow up of 5033 subjects in the Tromsø Study

BACKGROUND

The impact of moderate alcohol consumption on cognitive function and dementia is unclear. We examined the relationship between consumption of different alcoholic beverages and cognitive function in a large population-based study.

METHODS

Subjects were 5033 stroke-free men and women who participated in a longitudinal population-based study in Tromsø, Norway. Alcohol consumption and other cardiovascular risk factors were measured at baseline and cognitive function was assessed after 7 years follow up with verbal memory test, digit-symbol coding test and tapping test.

RESULTS

Moderate wine consumption was independently associated with better performance on all cognitive tests in both men and women. There was no consistent association between consumption of beer and spirits and cognitive test results. Alcohol abstention was associated with lower cognitive performance in women.

CONCLUSIONS

Light-to-moderate wine consumption was associated with better performance on cognitive tests after 7 years follow up.

Incidence of aneurysmal subarachnoid hemorrhage in Norway, 1999-2007

OBJECTIVE

To investigate changes and regional variations in annual incidence rates of aneurysmal subarachnoid hemorrhage (SAH) in Norway between 1999 and 2007.

METHODS

The authors retrospectively reviewed data from the Norwegian Patient Register for the period 1999-2007.

RESULTS

Crude incidence of aneurysmal SAH was 10.0/100,000 person years [95% CI (confidence interval): 9.7-10.3] and was higher in women (12.0/100,000 person years; 95% CI: 11.5-12.5) than men (8.1/100,000 person years; 95% CI: 7.7-8.4). Decreasing annual incidence rates were observed from 11.1/100,000 person years (95% CI: 10.5-11.6) in the period 1999-2001 to 8.9/100,000 person years (95% CI: 8.4-9.4) in the period 2005-2007 (P for trend <0.001). Regional variations were observed, from 8.4/100,000 person years (95% CI: 7.7-9.00) in the southern region, 10.4/100,000 person years (95% CI: 9.5-11.2) in the central region and 11.9/100,000 person years (95% CI: 10.8-12.9) in the northern region.

CONCLUSIONS

Incidence of aneurysmal SAH in Norway decreased from 1999 to 2007, with significant regional variations indicating an increasing gradient from south to north.

Impact of cardiovascular risk factors on cognitive function: the Tromsø study

BACKGROUND AND PURPOSE

The role of cardiovascular risk factors in the pathogenesis of cognitive impairment and dementia remains still unclear. We examined the impact of cardiovascular risk factors on cognitive function in a large longitudinal population study.

METHODS

Subjects were 5033 stroke-free men and women who participated in a longitudinal population-based study. Cardiovascular risk factors were measured at baseline, and cognitive function was assessed after 7 years of follow-up with verbal memory test, digit-symbol coding test, and tapping test.

RESULTS

Diabetes, systolic blood pressure, and current smoking were independently associated with lower cognitive test results in men and women. Low physical activity was independently associated with lower scores in women. We found no consistent association between total-cholesterol, HDL-cholesterol, coronary heart disease or BMI, and cognitive test results.

CONCLUSIONS

Diabetes, smoking, hypertension, and low physical activity were associated with lower cognitive test results. The study suggests that these modifiable risk factors should be emphasized in the prevention of cognitive decline.

Relation between serum osteoprotegerin and carotid intima media thickness in a general population - the Tromsø Study

BACKGROUND

 Previous studies have reported conflicting results on the relation between serum osteoprotegerin (OPG) concentration and carotid intima media thickness (CIMT).

PATIENTS/METHODS

 The present study was conducted to investigate the relations between OPG, risk factors for cardiovascular diseases (CVD) and carotid intima media thickness (CIMT) in a large cross-sectional study including 6516 subjects aged 25-85years who participated in a population-based health survey.

RESULTS

 CIMT increased significantly across tertiles of OPG after adjustment for traditional cardiovascular risk factors such as age, gender, smoking, total cholesterol, high-density lipoprotein (HDL) cholesterol, C-reactive protein (CRP), body mass index (BMI), systolic blood pressure, CVD and diabetes mellitus (P<0.0001). There was a significant interaction between age and OPG (P=0.026). The risk of being in the uppermost quartile of CIMT was reduced (OR 0.52, 95% CI 0.30-0.88) with each standard deviation (SD) higher level of OPG in subjects <45years (n=444), whereas subjects ≥55years of age (n=4884) had an increased risk of being in the uppermost quartile of CIMT (OR 1.19, 95% CI 1.10-1.29) after adjustment for traditional CVD risk factors.

CONCLUSIONS

Age has a differential impact on the association between OPG and CIMT in a general population. The present findings may suggest that increased serum OPG does not promote early atherosclerosis in younger subjects.

Serum osteoprotegerin, sRANKL and carotid plaque formation and growth in a general population--the Tromsø study

SUMMARY BACKGROUND

Intervention studies in animal models suggest that osteoprotegerin (OPG) functions as an inhibitor or marker of atherosclerosis, whereas one prospective epidemiological study in humans indicated that OPG was an independent risk factor for progression of atherosclerosis.

OBJECTIVE

To study the association between serum levels of OPG, soluble RANK ligand (sRANKL) and carotid artery plaque formation and plaque growth.

PATIENTS/METHODS

The prevalence of carotid plaque and plaque area were assessed by ultrasonographic imaging at baseline and after 7 years follow-up in 2191 men and 2329 women who participated in a population-based study.

RESULTS

OPG was significantly associated with atherosclerotic plaque burden and cardiovascular risk factors such as age, body mass index, blood pressure, total cholesterol, HDL cholesterol, HbA1c and fibrinogen at baseline, but not with sRANKL. In subjects without plaque at baseline, OPG predicted plaque formation in crude analysis in both women and men, but not after adjustment for age and other atherosclerotic risk factors. OPG predicted plaque growth in women (+1.8 mm(2), 0.6-3.0) (mean, 95% CI) per 1 SD increase in OPG (P = 0.003), whereas no associations were demonstrated in men (0.1 mm(2) (-1.3-1.4), P = 0.93). Soluble RANKL did not predict plaque formation or plaque growth.

CONCLUSIONS

OPG was an independent predictor of plaque growth in women, but not in men, suggesting gender-specific actions of OPG in plaque growth. OPG was not associated with novel plaque formation.

Mean platelet volume is a risk factor for venous thromboembolism: the Tromsø Study, Tromsø, Norway

BACKGROUND

Platelet size, measured as mean platelet volume (MPV), is associated with platelet reactivity. MPV is increased in acute myocardial infarction, and has been identified as an independent risk factor for future myocardial infarction and stroke.

OBJECTIVES

The purpose of the study was to determine the impact of platelet count and MPV on the incidence of venous thromboembolism (VTE) in a prospective, population-based study.

METHODS

Platelet count, MPV and baseline characteristics were registered in 25 923 subjects aged 25-96 years who participated in the Tromsø Study in 1994-1995. Incident VTE events were registered to the end of follow-up (1 September 2007).

RESULTS

There were 445 validated incident VTE events (1.6 per 1000 person-years), of which 186 (42%) were unprovoked, during a mean of 10.8 years of follow-up. Subjects with MPV >or= 9.5 fL had a 1.3-fold [95% confidence interval (CI) 1.0-1.7] higher risk of total VTE and a 1.5-fold (95% CI 1.1-2.3) higher risk of unprovoked VTE than subjects with MPV < 8.5 fL in analyses adjusted for age, sex, smoking, body mass index, and platelet count. Increasing MPV was associated with increased risk of total VTE (P for trend = 0.09) and unprovoked VTE (P for trend = 0.03) in analyses adjusted for age and sex. There was no significant association between increasing platelet count and risk of VTE.

CONCLUSIONS

An increasing MPV was identified as a predictor for VTE, in particular VTE of unprovoked origin. The present findings support the concept that platelet reactivity is important in the pathogenesis of VTE.

Ultrasonographic measurements of subclinical carotid atherosclerosis in prediction of ischemic stroke

Carotid intima-media thickness (IMT) and plaque measurements are widely used to quantify atherosclerosis and assess the risk of future stroke, and are used as surrogate endpoints for clinical disease. In recent years, it has become clear that carotid IMT and plaque reflect biologically and genetically different aspects of the atherosclerotic process, and are differentially related to risk factors and cardiovascular disease. Plaques are focal manifestations of atherosclerosis while increased IMT represents mainly hypertensive medial hypertrophy. Several prospective studies have showed that IMT and plaque measurements, such as total plaque area and plaque number, are predictive of future stroke. Plaque echogenicity predicts future stroke independent of plaque size. The contribution of IMT and plaque measurements in individual stroke risk prediction in the general population seems to be limited, but may be useful as a tool for individual stratification of high-risk patients.

Abdominal obesity is essential for the risk of venous thromboembolism in the metabolic syndrome: the Tromsø study

SUMMARY BACKGROUND

The metabolic syndrome is a cluster of cardiovascular risk factors, including abdominal obesity, hypertension, dyslipidemia and insulin resistance, associated with increased risk of cardiovascular diseases and all cause mortality.

OBJECTIVES

The purpose of the study was to assess the impact of the metabolic syndrome, and its individual components, on the risk of venous thromboembolism (VTE) in a prospective population-based study.

METHODS

Individual components of the metabolic syndrome were registered in 6170 subjects aged 25-84 years in the Tromsø Study in 1994-1995, and first ever VTE events were registered until 1 September 2007.

RESULTS

The metabolic syndrome was present in 21.9% (1350 subjects) of the population. There were 194 validated first VTE events (2.92 per 1000 person-years) during a mean of 10.8 years of follow-up. Presence of metabolic syndrome was associated with increased risk of VTE (HR, 1.65; 95% CI, 1.22-2.23) in age- and gender-adjusted analysis. The risk of VTE increased with the number of components in the metabolic syndrome (P < 0.001). Abdominal obesity was the only component significantly associated with VTE in multivariable analysis including age, gender, and the individual components of the syndrome (HR, 2.03; 95% CI, 1.49-2.75). When abdominal obesity was omitted as a diagnostic criterion, none of the other components, alone or in cluster, was associated with increased risk of VTE.

CONCLUSIONS

Our study provides evidence for the metabolic syndrome as a risk factor for TE. Abdominal obesity appeared to be the pivotal risk factor among the individual components of the syndrome.

Family history of myocardial infarction is an independent risk factor for venous thromboembolism: the Tromsø study

BACKGROUND

Recent studies indicate that arterial cardiovascular diseases and venous thromboembolism (VTE) share common risk factors. A family history of myocardial infarction (MI) is a strong and independent risk factor for future MI.

OBJECTIVES

The purpose of the present study was to determine the impact of cardiovascular risk factors, including family history of MI, on the incidence of VTE in a prospective, population-based study.

PATIENTS AND METHODS

Traditional cardiovascular risk factors and family history of MI were registered in 21,330 subjects, aged 25-96 years, enrolled in the Tromsø study in 1994-95. First-lifetime VTE events during follow-up were registered up to 1 September 2007.

RESULTS

There were 327 VTE events (1.40 per 1000 person-years), 138 (42%) unprovoked, during a mean of 10.9 years of follow-up. In age- and gender-adjusted analysis, age [hazard ratio (HR) per decade, 1.97; 95% confidence interval (CI), 1.82-2.12], gender (men vs. women; HR, 1.25; 95% CI, 1.01-1.55), body mass index (BMI; HR per 3 kg m(-2), 1.21; 95% CI, 1.13-1.31), and family history of MI (HR, 1.31; 95% CI, 1.04-1.65) were significantly associated with VTE. Family history of MI remained a significant risk factor for total VTE (HR, 1.27; 95% CI, 1.01-1.60) and unprovoked VTE (HR, 1.46; 95% CI, 1.03-2.07) in multivariable analysis. Blood pressure, total cholesterol, HDL-cholesterol, triglycerides, and smoking were not independently associated with total VTE.

CONCLUSIONS

Family history of MI is a risk factor for both MI and VTE, and provides further evidence of a link between venous and arterial thrombosis.

[Risk factors for cerebral stroke]

BACKGROUND

Stroke is a heterogenic group of disorders. Cerebral infarction is the largest group (80-85%) and is followed by primary intracerebral hemorrhage and subarachnoid hemorrhage. This article gives a review of risk factors for cerebral stroke, with an emphasis on cerebral infarction.

MATERIAL AND METHODS

The article is based on literature identified through Medline, with emphasis on prospective, population-based studies.

RESULTS AND INTERPRETATION

Genetic studies of the Icelandic population have shown associations between single genes and common types of stroke, but it remains to be seen whether the results can be replicated in other populations. High blood pressure and cigarette smoking are the most important modifiable risk factors for stroke. Serum cholesterol is positively associated with cerebral infarction, but not with intracerebral hemorrhage. Diabetes, atrial fibrillation and carotid stenosis are important predictors of cerebral infarcts, especially in the elderly. Cohort studies and randomized trials have shown that hormone replacement therapy in women increases the risk of stroke, while modern oral contraceptives do not represent a risk factor for stroke in young women. There is a clear social gradient in stroke occurrence, with a higher incidence in lower social classes.

Endothelial dysfunction and systemic inflammation in persons with echolucent carotid plaques

Echolucent carotid plaques are associated with high risk for future ischemic cerebrovascular events independent of the degree of stenosis. Elevated levels of markers of systemic inflammation and endothelial dysfunction are predictors for future myocardial infarction and stroke. The present study was undertaken to investigate the relations between plaque morphology, endothelial dysfunction assessed by tissue-plasminogen activator antigen (t-PA ag) and vonWillebrand factor (vWF), and systemic inflammation in persons with carotid stenosis. We conducted a crosssectional study including 133 persons with carotid stenosis and 138 controls without stenosis recruited from the populationbased Tromsø Study. High-resolution B-mode and colour Doppler/pulsed-wave Doppler ultrasonography of both carotid arteries was performed, and plaque morphology in terms of echogenicity was assessed. Persons with carotid stenosis had significantly higher plasma t-PA and vWF concentrations than controls. There was a significant inverse relationship between t-PA ag and plaque echogenicity (p = 0.034). The increased plasma t-PA ag in persons with carotid stenosis was not associated with increased plasminogen activator inhibitor-I (PAI-1). Persons with echolucent carotid plaques had higher degree of systemic inflammation, and plasma t-PA and vWF concentration increased significantly across quartiles of WBC, fibrinogen, and hs-CRP. Our findings may suggest that plasma t-PA may be superior to vWF as a marker for endothelial dysfunction due to its ability to discriminate between various plaque echogenicity, and that the predictive role of t-PA ag in cardiovascular disease is independent of inhibited fibrinolysis.

Carotid plaque echogenicity and risk of nonvertebral fractures in women: a longitudinal population-based study

Atherosclerosis and osteoporosis appear to be related, but prospective studies on the relationship are sparse. In order to examine whether carotid artery plaques with different morphology predict nonvertebral fractures, we followed 2,733 women, aged 55-74 years (75% of the eligible population in Tromsø, Norway), for 6 years. At baseline, plaque morphology in terms of ultrasound echogenicity was categorized into three groups, ranging from low echogenicity (echolucent plaques with a high content of soft tissue) to strong echogenicity (echogenic plaques with a high content of dense fibrous tissue and calcified material). We found that the age-adjusted relative risk (RR) of fracture was significantly higher among women with echogenic plaques than among women without plaques: 1.7 (95% confidence interval [CI] 1.0-2.7). After adjustment for bone mineral density at baseline in addition to age, the RR was 1.6 (95% CI 1.0-2.6), and further adjustments for body mass index, body height, high-density lipoprotein cholesterol, smoking status, and muscle strength did not influence the association. Subjects with other plaque types were not at an increased risk compared to subjects without plaques: RR < or = 1.1, after multiple adjustments. We conclude that in the general population elderly women with echogenic carotid plaques are at higher risk of nonvertebral fractures than women without plaques.

Reduced neuropsychological test performance in asymptomatic carotid stenosis: The Tromso Study

OBJECTIVE

To assess the relationship between asymptomatic carotid stenosis, neuropsychological test performance, and silent MRI lesions.

METHODS

Performance on several neuropsychological tests was compared in 189 subjects with ultrasound-assessed carotid stenosis and 201 control subjects without carotid stenosis, recruited from a population health study. Subjects with a previous history of stroke were excluded. The test battery included tests of attention, psychomotor speed, memory, language, speed of information processing, motor functioning, intelligence, and depression. Sagittal T1-weighted and axial and coronal T2-weighted spin echo MRI was performed, and presence of MRI lesions (white matter hyperintensities, lacunar and cortical infarcts) was recorded.

RESULTS

Subjects with carotid stenosis had significantly lower levels of performance in tests of attention, psychomotor speed, memory, and motor functioning, independent of MRI lesions. There were no significant differences in tests of speed of information processing, word association, or depression. Cortical infarcts and white matter hyperintensities were equally distributed among persons with and without carotid stenosis. Lacunar infarcts were more frequent in the stenosis group (p = 0.03).

CONCLUSIONS

Carotid stenosis was associated with poorer neuropsychological performance. This could not be explained by a higher proportion of silent MRI lesions in persons with asymptomatic carotid stenosis, making it less likely that the cognitive impairment was caused by silent emboli.

Prevalence of and risk factors associated with carotid artery stenosis: the Tromsø Study

BACKGROUND AND PURPOSE

To assess prevalence, distribution, ultrasound characteristics and determinants of carotid artery stenosis in a large, population-based study of both women and men.

METHODS

A total of 6,727 persons aged 25-84 years were screened for extracranial stenosis with Duplex ultrasound of the right carotid artery. Risk factors were compared in 225 persons with stenosis and 5,514 persons without.

RESULTS

The prevalence of carotid stenosis was higher in men than in women, where 3.8% (95% CI, 3.2-4.6%) had carotid stenosis, compared to 2.7% (95% CI, 2.2-3.3%) in women (p = 0.001). The prevalence gradually increased by age in both genders. Cholesterol, HDL cholesterol, fibrinogen, systolic blood pressure levels and current smoking were independently associated with carotid artery stenosis in both women and men. The presence of carotid stenosis was significantly associated with a history of cerebrovascular disease, coronary heart disease and peripheral artery disease. For each 10% increase in the degree of carotid stenosis, the risk of having had a cerebrovascular event increased by 26%.

CONCLUSIONS

The prevalence of carotid stenosis in the general population, as measured by ultrasound, is low. Age, male gender, smoking, total cholesterol, HDL cholesterol (inverse), fibrinogen and systolic blood pressure are all independent predictors of carotid artery stenosis.

Low levels of high-density lipoprotein cholesterol are associated with echolucent carotid artery plaques: the tromsø study

BACKGROUND AND PURPOSE

Ultrasound-assessed plaque morphology is an independent predictor of ischemic stroke. The purpose of this population-based cross-sectional nested case-control study was to examine the risk factors associated with carotid plaque morphology.

METHODS

Ultrasonography of the right carotid artery was conducted on 6727 participants in a population health survey (response rate 79%). Plaque echogenicity, defined as reflectance of the emitted ultrasound signal, was scored as echolucent, predominantly echolucent, predominantly echogenic, or echogenic. Information on cardiovascular risk factors in all 216 participants who had carotid stenosis and in 223 control subjects matched by age and sex who did not have carotid stenosis was obtained from measurements of blood pressure, weight, height, and nonfasting blood samples and from a self-administered questionnaire.

RESULTS

In both univariate and multivariate analyses, low levels of HDL cholesterol and increasing degree of stenosis were independently associated with an increased risk of having an echolucent plaque. For 1-SD increase in HDL cholesterol, the adjusted odds of being in a lower plaque echogenicity category decreased by approximately 30% (OR 0.69, 95% CI 0.52 to 0.93).

CONCLUSIONS

These findings indicate that low levels of HDL cholesterol are associated with an increased risk of having echolucent, rupture-prone atherosclerotic plaques.

Echolucent plaques are associated with high risk of ischemic cerebrovascular events in carotid stenosis: the tromsø study

BACKGROUND

The purpose of the study was to assess in a prospective design whether plaque morphology is associated with risk of ischemic stroke and other cerebrovascular events in subjects with carotid stenosis.

METHODS AND RESULTS

A total of 223 subjects with carotid stenosis (123 with 35% to 49% degree of stenosis, 100 with 50% to 99% stenosis) and 215 control subjects matched by age and sex who participated in a population health survey at baseline were followed up for 3 years. Plaque echogenicity was assessed by ultrasound at baseline and scored as echolucent, predominantly echolucent, predominantly echogenic, or echogenic. Forty-four subjects experienced >/=1 ischemic cerebrovascular events in the follow-up period. Plaque echogenicity, degree of stenosis, and white blood cell count were independent predictors of cerebrovascular events. The unadjusted relative risk for cerebrovascular events was 13.0 (95% CI 4.5 to 37.4) in subjects with echolucent plaques and 3.7 (95% CI 0.7 to 18.2) in subjects with echogenic plaques when subjects without stenosis were used as the reference. The adjusted relative risk for cerebrovascular events in subjects with echolucent plaques was 4.6 (95% CI 1.1 to 18.9), and there was a significant linear trend (P=0.015) for higher risk with increasing plaque echolucency. The adjusted relative risk for a 10% increase in the degree of stenosis was 1.2 (95% CI 1.04 to 1.4).

CONCLUSIONS

Subjects with echolucent atherosclerotic plaques have increased risk of ischemic cerebrovascular events independent of degree of stenosis and cardiovascular risk factors. Subjects at high risk for ischemic vascular events may be identified by ultrasound assessment of plaque morphology.

The uncemented fully textured Lord hip prosthesis: a 10- to 15-year followup study

One hundred fourteen total hip arthroplasties in 110 patients performed between 1979 and 1983 using the Lord femoral component were analyzed. Nine femoral revisions were performed within 13 years after surgery (two because of infection). Excluding infections there was a 94% 13-year survival according to a Kaplan-Meier analysis. Subsidence was seen in five hips (five patients), but only one needed revision surgery. Seventy-six hips (73 patients) had a radiographic followup of 10 years or more and were analyzed in detail. Changes in cortical thickness, density, and formation of spotwelds continued beyond 5 years after surgery, meaning the remodeling of periprosthetic bone continued beyond that time. Osteolysis on the femoral side was seen in seven hips, always in the proximal part of the femur, apparently as a continuation of the joint space. No remote focal osteolysis was seen. Elderly patients, women, and patients with a pedestal were overrepresented among individuals with many spotwelds. For the clinical outcome the Merle d'Aubigne and Postel score as modified by Charnley was used. Among 69 hips (66 patients) with a mean followup of 153 months 96% (66 hips) had a pain score equal to or greater than 4 and 74% (51 hips) had a score of 5 or 6. The Lord femoral component gave surprisingly good clinical long term results despite the bone remodeling (stress shielding), which in some cases was pronounced. The most obvious disadvantage with this design appears to be the difficulties associated with its removal when indicated.

Prediction of mortality by ultrasound screening of a general population for carotid stenosis: the Tromsø Study

BACKGROUND AND PURPOSE

The extensive use of ultrasound examination of carotid arteries has revealed stenosis in many asymptomatic subjects, and clinical studies have shown that carotid stenosis is a risk factor for cardiovascular disease and death. However, information on stenosis as detected in a general population and its relation to mortality is scarce. The purpose of this population-based study was to assess whether carotid stenosis is a predictor of death.

METHODS

In 1994 to 1995, 248 subjects with suspected carotid stenosis were identified among 6727 men and women 25 to 84 years of age who were examined with ultrasound. These subjects and 496 age- and sex-matched control subjects were followed up for 4.2 years, and the number and causes of deaths were registered.

RESULTS

The unadjusted relative risk for death was 2.72 (95% CI, 1.57 to 4.75) for subjects with stenosis compared with control subjects. Adjusting for cardiovascular risk factors increased the relative risk to 3.47 (95% CI, 1.47 to 8.19). The adjusted relative risk in persons with stenosis and no cardiovascular disease or diabetes was 5.66 (95% CI, 1.53 to 20.90), which was higher than in subjects with stenosis and self-reported disease (1.79; 95% CI, 0.75 to 4.27). There was a dose-response relationship between degree of stenosis and risk of death (P=0.002 for linear trend). Carotid stenosis was a stronger predictor of death than self-reported cardiovascular disease or diabetes.

CONCLUSIONS

Carotid stenosis is a strong and independent predictor of death.