Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population

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Background:

Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.

Methods:

We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease (ie, no previous myocardial infarctions or cardiac procedures) and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment (defined as no atherosclerosis, 1% to 49% stenosis, or ≥50% stenosis). External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.

Results:

In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.

Conclusions:

Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk.

Maternal mood disorders and lithium exposure in utero were not associated with poor cognitive development during childhood

AIM

This study evaluated whether maternal mood disorders (MMD), particularly bipolar disorder, and lithium treatment during pregnancy influenced the neonatal health and cognition of children born from 2006 to 2010.

METHODS

Our study at Karolinska University Hospital, Stockholm, Sweden, focused on women with and without mood disorders and their children. Information on pharmacotherapy, mental health, delivery and neonatal complications was retrospectively collected from electronic patient records. Children were tested in a blinded manner at four to five years of age with the Wechsler Preschool and Primary Scale of Intelligence, 3rd edition. Maternal health, child health and social situations were evaluated.

RESULTS

Of the 39 children, 20 were exposed to lithium and MMD during pregnancy, eight were exposed to MMD but not lithium and 11 were not exposed to MMD or lithium. The children's full scale intelligence quotient (IQ), performance IQ and verbal IQ results did not differ significantly between the groups. The processing speed quotient was significantly lower in children exposed to mood disorders, but there was a high level of missing data for this subtest.

CONCLUSION

This small, clinical cohort showed no significant association between mothers' prenatal exposure to lithium or mood disorders and their offspring's IQ.

Socioeconomic differences in smoking cessation: the role of social participation

Objectives: The aim of this study was to investigate whether psychosocial resources explain socioeconomic differences in smoking cessation and its maintenance. Methods: A subpopulation of 11,837 individuals from the Malmö Diet and Cancer Study interviewed in 1992-94, age range 45-64 years, was investigated in this cross-sectional study. A multivariate logistic regression model was used to assess relative risks of having stopped smoking, adjusting for age, country of origin, previous/ current diseases, and marital status. Results: An odds ratio of 1.9 (1.4-2.5; 95% CI) for men and 2.0 (1.4-2.7; 95% CI) for women of having stopped smoking was found for higher non-manual employees when compared with unskilled manual workers. A decrease in these odds ratios was found when social participation was introduced into the model. The other three social network and social support variables were non-significant. Conclusion: High social participation is a predictor of maintenance of smoking cessation. It seems possible to interpret parts of the socioeconomic differences in smoking cessation and its maintenance as a consequence of differing social network resources and social capital between socioeconomic groups.

Incidence of cardiovascular disease, cancer and death in postmenopausal women affirming use of hormone replacement therapy

Aim: The goal of this study was to evaluate the incidence of myocardial infarction, cancer and death in relation to use of hormone replacement therapy (HRT). Methods : Nine years' follow up of an urban cohort of peri-/postmenopausal women was undertaken. Local and national registers were used for retrieval of events. Results: The incidence of myocardial infarction per 1,000 person-years in users and non-users was 0.61 (5/962) and 2.20 (92/4759) respectively, adjusted relative risk (RR) 0.37; 95% confi dence interval 0.15-0.90. Rates of mortality from cardiovascular disease and cancer were 0.36 and 1.10, p= 0.058, and 2.60 and 2.09, p=0.360, respectively. In terms of all-cause mortality the adjusted RR was 1.02; 0.69- 1.52, incidence of cancer 1.28; 1.01-1.64, breast cancer 1.52; 1.01-2.28 and endometrial cancer 3.61; 1.54-8.46 . Conclusions: Women affirming use of HRT had a lower incidence of myocardial infarction. Further studies are needed to assess whether the absence of effect on total mortality may be accounted for by an increased cancer risk.

COHb% as a marker of cardiovascular risk in never smokers: Results from a population-based cohort study

Aim: Carbon monoxide (CO) in blood as assessed by the COHb% is a marker of the cardiovascular (CV) risk in smokers. Non-smokers exposed to tobacco smoke similarly inhale and absorb CO. The objective in this population-based cohort study has been to describe inter-individual differences in COHb% in never smokers and to estimate the associated cardiovascular risk. Methods: Of the 8,333 men, aged 34—49 years, from the city of Malmö, Sweden, 4,111 were smokers, 1,229 ex-smokers, and 2,893 were never smokers. Incidence of CV disease was monitored over 19 years of follow up. Results: COHb% in never smokers ranged from 0.13% to 5.47%. Never smokers with COHb% in the top quartile (above 0.67%) had a significantly higher incidence of cardiac events and deaths; relative risk 3.7 (95% CI 2.0—7.0) and 2.2 (1.4—3.5), respectively, compared with those with COHb% in the lowest quartile (below 0.50%). This risk remained after adjustment for confounding factors. Conclusion: COHb% varied widely between never-smoking men in this urban population. Incidence of CV disease and death in non-smokers was related to COHb%. It is suggested that measurement of COHb% could be part of the risk assessment in non-smoking patients considered at risk of cardiac disease. In random samples from the general population COHb% could be used to assess the size of the population exposed to second-hand smoke.

Collaborative meta-analysis of individual participant data from observational studies of Lp-PLA2 and cardiovascular diseases

BACKGROUND

A large number of observational epidemiological studies have reported generally positive associations between circulating mass and activity levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and the risk of cardiovascular diseases. Few studies have been large enough to provide reliable estimates in different circumstances, such as in different subgroups (e.g., by age group, sex, or smoking status) or at different Lp-PLA2 levels. Moreover, most published studies have related disease risk only to baseline values of Lp-PLA2 markers (which can lead to substantial underestimation of any risk relationships because of within-person variability over time) and have used different approaches to adjustment for possible confounding factors.

OBJECTIVES

By combination of data from individual participants from all relevant observational studies in a systematic 'meta-analysis', with correction for regression dilution (using available data on serial measurements of Lp-PLA2), the Lp-PLA2 Studies Collaboration will aim to characterize more precisely than has previously been possible the strength and shape of the age and sex-specific associations of plasma Lp-PLA2 with coronary heart disease (and, where data are sufficient, with other vascular diseases, such as ischaemic stroke). It will also help to determine to what extent such associations are independent of possible confounding factors and to explore potential sources of heterogeneity among studies, such as those related to assay methods and study design. It is anticipated that the present collaboration will serve as a framework to investigate related questions on Lp-PLA2 and cardiovascular outcomes.

METHODS

A central database is being established containing data on circulating Lp-PLA2 values, sex and other potential confounding factors, age at baseline Lp-PLA2 measurement, age at event or at last follow-up, major vascular morbidity and cause-specific mortality. Information about any repeat measurements of Lp-PLA2 and potential confounding factors has been sought to allow adjustment for possible confounding and correction for regression dilution. The analyses will involve age-specific regression models. Synthesis of the available observational studies of Lp-PLA2 will yield information on a total of about 15 000 cardiovascular disease endpoints.

Social mobility, marital status, and mortality risk in an adult life course perspective: The Malmö Preventive Project

Aims: Adverse social factors predict increased mortality. This study aimed to assess the influence of social class and marital status on mortality, adding an adult life course perspective. Methods: In total, 32,907 males and 20,204 females were evaluated based on census data in Malmö, Sweden. Of these subjects, 22,444 males and 10,902 females also took part in health screening. The main outcomes were all-cause and cause-specific mortality rates in subgroups based on social class and marital status, either measured once or repeatedly in adult life. Results were based on a total of 522,807 years of follow-up in men (5,761 deaths) and 239,815 in women (1,354 deaths). Results: Total and cardiovascular mortality were significantly higher in manual male employees with age-adjusted risk ratios (RR) of 1.7 (95% CI 1.5—1.9) and 1.6 (1.3—2.0) in skilled manual workers, and 2.0 (1.7—2.2) and 1.9 (1.6—2.3) in unskilled manual workers, compared with high-level non-manual employees. The differences remained after adjustment for baseline risk factors and prevalent cardiovascular disease, and were similar for women. Increased mortality risk was also documented for subjects who were divorced or unmarried (adjusted for social class), as well as being downward socially mobile or in a permanent low social class (manual) position. Conclusions: Social class based on occupation, either measured once or repeatedly in adult life, is associated with marked differences in mortality risk in middle-aged subjects. People who remain married/cohabiting or remarry are at lower risk of early death than people who remain unmarried or divorced.

The Swedish CArdioPulmonary BioImage Study: objectives and design

Cardiopulmonary diseases are major causes of death worldwide, but currently recommended strategies for diagnosis and prevention may be outdated because of recent changes in risk factor patterns. The Swedish CArdioPulmonarybioImage Study (SCAPIS) combines the use of new imaging technologies, advances in large-scale 'omics' and epidemiological analyses to extensively characterize a Swedish cohort of 30 000 men and women aged between 50 and 64 years. The information obtained will be used to improve risk prediction of cardiopulmonary diseases and optimize the ability to study disease mechanisms. A comprehensive pilot study in 1111 individuals, which was completed in 2012, demonstrated the feasibility and financial and ethical consequences of SCAPIS. Recruitment to the national, multicentre study has recently started.

Sodium excretion and sympathetic activity in relation to severity of hypertension

The relationship between the severity of hypertensive disease and sodium excretion and sympathetic activity has been studied in normotensive (n = 19) and hypertensive (n = 19) men of the same derived from screening a total population. Sympathetic activity was determined from noradrenaline excretion and the severity of hypertension was assessed by measuring resting diastolic BP, left ventricular hypertrophy on orthogonal ECG and the glomerular filtration rate. In the hypertensive group the resting BP correlated well both with signs of left ventricular hypertrophy, i.e. with the degree of severity of the hypertensive disease. Up to the level of 90 mm Hg resting diastolic BP, sodium excretion rose in agreement with theory of pressure diuresis. Above 90 mm Hg, however, both sodium and noradrenaline excretion fell with increasing BP. This indicated that in more advanced hypertension the sodium balance overrides the sympathetic activity in the long-term relation of BP. In another series of 49-year-old-men noradrenaline excretion fell with increasing renal vascular resistance indicating that the increase in the latter variable could not be explained by increased sympathetic tone. On the basis of the results a hypothesis on the sequence of events leading to development of hypertension, is presented.

Effects of long-term averaging of quantitative blood pressure traits on the detection of genetic associations

Blood pressure (BP) is a heritable, quantitative trait with intraindividual variability and susceptibility to measurement error. Genetic studies of BP generally use single-visit measurements and thus cannot remove variability occurring over months or years. We leveraged the idea that averaging BP measured across time would improve phenotypic accuracy and thereby increase statistical power to detect genetic associations. We studied systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP) averaged over multiple years in 46,629 individuals of European ancestry. We identified 39 trait-variant associations across 19 independent loci (p < 5 × 10(-8)); five associations (in four loci) uniquely identified by our LTA analyses included those of SBP and MAP at 2p23 (rs1275988, near KCNK3), DBP at 2q11.2 (rs7599598, in FER1L5), and PP at 6p21 (rs10948071, near CRIP3) and 7p13 (rs2949837, near IGFBP3). Replication analyses conducted in cohorts with single-visit BP data showed positive replication of associations and a nominal association (p < 0.05). We estimated a 20% gain in statistical power with long-term average (LTA) as compared to single-visit BP association studies. Using LTA analysis, we identified genetic loci influencing BP. LTA might be one way of increasing the power of genetic associations for continuous traits in extant samples for other phenotypes that are measured serially over time.

A common missense variant in the ATP receptor P2X7 is associated with reduced risk of cardiovascular events

Background and Purpose

Extracellular adenosine triphosphate (ATP) regulates inflammatory cells by activation of the P2X₇ receptor. We hypothesized that polymorphisms in P2RX7 influence the risk of ischemic heart disease (IHD), ischemic stroke (IS) and cardiovascular risk factors and tested this hypothesis using genetic association studies.

Methods

Two loss-of-function SNPs in P2RX7 were genotyped in 1244 IHD cases and 2488 controls as well as 5969 individuals with cardiovascular risk factors. Eleven SNPs in a 250 kb region on chromosome 12 spanning P2RX7 as well as neighboring genes OASL, P2RX4 and CAMKK2 were genotyped in 4138 individuals with IS and 2528 controls. Association was examined using linear and logistic regression models with an additive genetic model.

Results

The common loss-of-function variant rs3751143 was significantly associated with a decreased risk of IHD in smokers (P = 0.03) as well as decreased risk of IS (OR 0.89; 95% CI = 0.81–0.97; P = 0.012). In addition, an intronic SNP in CAMKK2, rs2686342, were associated with a decreased risk of IS (OR 0.89; 95% CI = 0.82–0.97; P = 0.011). In subgroup analyses, both SNPs were associated with decreased risk of IS in individuals with hypertension (P = 0.045 and 0.015, respectively).

Conclusions

A common loss-of-function missense variant in the gene encoding the P2X₇ receptor is associated with reduced risk of IS and with IHD in smokers. These findings might implicate a role of purinergic signaling in atherogenesis or atherothrombosis.

Long-term treatment with low-dose metoprolol CR/XL is associated with increased plaque echogenicity: the Beta-blocker Cholesterol-lowering Asymptomatic Plaque Study (BCAPS)

OBJECTIVES

To examine whether the decrease in IMT progression rate in the carotid bulb induced by metoprolol CR/XL treatment (25mg once daily) observed in the β-blocker Cholesterol-lowering Asymptomatic Plaque Study (BCAPS) was accompanied by an effect on carotid plaque echogenicity.

METHODS

Gray scale median (GSM) in carotid plaques, used as a score of echogenicity, was measured at baseline and after 36 months in those 341 subjects (aged 49-69 years) with an asymptomatic moderate- to large-sized carotid plaque present at baseline and at follow-up. Participants were in a factorial design assigned to treatment with metoprolol CR/XL (25mg once daily), fluvastatin (40 mg once daily) or corresponding placebo.

RESULTS

After 36 months plaques were more echogenic in participants treated compared to those not treated with metoprolol CR/XL (57.3 ± 16.8 versus 51.8 ± 20.0, p=0.006). GSM had increased more from baseline in the metoprolol CR/XL treated subjects (25 ± 15 versus 18 ± 20, p<0.001), and plaques that had become more echolucent were less frequent in the metoprolol CR/XL treated subjects (3.6% versus 17.0%, p<0.001).

CONCLUSIONS

Long-term treatment with low dose metoprolol CR/XL in clinically healthy subjects with moderate-sized carotid plaques was associated with increase in plaque echogenicity, suggesting a potential beneficial effect of the β-blocker treatment on plaque stability.

Increased cartilage turnover and circulating autoantibodies in different subsets before the clinical onset of rheumatoid arthritis

Background

Previous studies have indicated that autoantibodies may be detected years before the clinical onset of rheumatoid arthritis (RA). Cartilage biomarkers, such as cartilage oligomeric matrix protein (COMP), have not been studied previously in samples collected before the diagnosis of RA.

Methods

Between 1991 and 1996, 30 447 subjects were included in the Malmö Diet Cancer Study (MDCS). People who developed RA after inclusion were identified by linking the MDCS database to different Swedish registers. One matched control for each validated case was selected from the MDCS. IgG antibodies against cyclic citrullinated peptide (anti-CCP) and mutated citrullinated vimentin (anti-MCV) and IgM rheumatoid factor (IgM RF) were determined by ELISA. Serum COMP was measured with a sandwich ELISA.

Results

172 incident cases of RA (median time from inclusion to diagnosis 5 years; range 1–13) were identified. Pre-RA cases were significantly more likely than controls to be positive for anti-CCP (21.9% vs 0.6%), anti-MCV (29.6% vs 3.0%) and IgM RF (18.9% vs 2.4%) (all p<0.001). Overall, mean serum COMP levels did not differ between cases and controls. Among pre-RA cases included 1–3 years before diagnosis, raised COMP (>12 U/l) was seen in a greater proportion of anti-CCP-negative than anti-CCP-positive subjects (50% vs 15%; p=0.04).

Conclusions

Increased cartilage turnover, measured by COMP, and circulating RA-specific antibodies may be distinct processes in the preclinical phase of RA.

Occupation and risk of lymphoma: a multicentre prospective cohort study (EPIC)

OBJECTIVES

Evidence suggests that certain occupations and related exposures may increase the risk of malignant lymphoma. Farming, printing and paper industry, wood processing, meat handling and processing, welding, shoe and leather manufacturing and teaching profession are among the categories that have been implicated in previous studies. The relationship between occupation and malignant lymphoma has been investigated in a large European prospective study.

METHODS

We investigated occupational risks for lymphomas in the European Prospective Investigation into Cancer and Nutrition (EPIC). The mean follow-up time for 348,555 subjects was 9 years (SD: 2 years). The analysis was based on 866 and 48 newly diagnosed cases of non-Hodgkin's lymphoma (NHL) and Hodgkin's lymphoma (HL). These were identified in the EPIC subcohorts with occupational data. Data on 52 occupations were collected through standardised questionnaires. Cox proportional hazard models were used to explore the association between occupation and risk of malignant lymphoma.

RESULTS

The following occupations were positively associated with malignant NHL after adjustment for study centre, age, sex, socioeconomic status (SES), smoking and alcohol: butchers (HR=1.53, 95% CI 1.05 to 2.48, including multiple myeloma/plasmacytoma; HR=1.30, 95% CI 1.00 to 2.66, excluding multiple myeloma/plasmacytoma) and car repair workers (HR=1.50, 95% CI 1.01 to 2.00, including multiple myeloma/plasmacytoma; HR=1.51, 95% CI 1.01 to 2.31, excluding multiple myeloma/plasmacytoma). HL was associated with gasoline station occupation (HR=4.59, 95% CI 1.08 to 19.6).

CONCLUSION

The findings in this current study of a higher risk of NHL among car repair workers and butchers and a higher risk of HL among gasoline station workers suggest a possible role from occupationally related exposures, such as solvents and zoonotic viruses, as risk factors for malignant lymphoma.

Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables

Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context of multiple genetic markers measured in multiple studies, based on the analysis of individual participant data. First, for a single genetic marker in one study, we show that the usual ratio of coefficients approach can be reformulated as a regression with heterogeneous error in the explanatory variable. This can be implemented using a Bayesian approach, which is next extended to include multiple genetic markers. We then propose a hierarchical model for undertaking a meta-analysis of multiple studies, in which it is not necessary that the same genetic markers are measured in each study. This provides an overall estimate of the causal relationship between the phenotype and the outcome, and an assessment of its heterogeneity across studies. As an example, we estimate the causal relationship of blood concentrations of C-reactive protein on fibrinogen levels using data from 11 studies. These methods provide a flexible framework for efficient estimation of causal relationships derived from multiple studies. Issues discussed include weak instrument bias, analysis of binary outcome data such as disease risk, missing genetic data, and the use of haplotypes.

Weak associations between human leucocyte antigen genotype and acute myocardial infarction

OBJECTIVES

Human leucocyte antigens (HLAs) are polymorphic molecules involved in antigen presentation. Associations between HLA type and autoimmune diseases, such as type 1 diabetes and rheumatoid arthritis, are well established but the potential association of genetic variation affecting antigen presentation with cardiovascular disease has not been systematically investigated in large cohorts. The importance of such studies is stressed by recent experimental findings of an involvement of autoimmunity in the atherosclerotic disease process.

RESULTS

An SSP-PCR method was used for HLA genotyping to determine associations of HLA-DRB1, -DQA1 and -DQB1 with cardiovascular disease in a population-based cohort of 1188 acute myocardial infarction (AMI) patients and 1191 matched healthy controls. The HLA-DRB1*0101 allele, as well as the HLA-DRB1*0101-DQA1*01-DQB1*05 haplotype, was found to be associated with increased risk for AMI (OR 1.24; 95% CI 1.00-1.54 for both). In contrast, the DRB1*07 and DQA*02 alleles (OR 0.78; 95% CI 0.65-0.95 for both), as well as the DRB1*07-DQA*02-DQB*02 haplotype, conferred protection (OR 0.79; 95% CI 0.63-0.98). An HLA risk score taking each individual's both haplotypes into account was higher amongst cases (2.43 +/- 0.92 vs. 2.29 +/- 0.95, P = 0.001). The association between HLA risk score and AMI was independent of other cardiovascular risk factors assessed.

CONCLUSIONS

This study demonstrates that the associations between HLA-DRB1 and DQA1 loci and cardiovascular disease exists but that they are considerably weaker than those previously reported for other diseases with an established autoimmune aetiology such as type 1 diabetes, systemic lupus erythematosus and rheumatoid arthritis.

Plasma copeptin and the risk of diabetes mellitus

BACKGROUND

Animal studies suggest that the arginine vasopressin system may play a role in glucose metabolism, but data from humans are limited.

METHODS AND RESULTS

We analyzed plasma copeptin (copeptin), a stable C-terminal fragment of the arginine vasopressin prohormone. Using baseline and longitudinal data from a Swedish population-based sample (n=4742; mean age, 58 years; 60% women) and multivariable logistic regression, we examined the association of increasing quartiles of copeptin (lowest quartile as reference) with prevalent diabetes mellitus at baseline, insulin resistance (top quartile of fasting plasma insulin among nondiabetic subjects), and incident diabetes mellitus on long-term follow-up. New-onset diabetes mellitus was ascertained through 3 national and regional registers. All models were adjusted for clinical and anthropometric risk factors, cystatin C, and C-reactive protein. In cross-sectional analyses, increasing copeptin was associated with prevalent diabetes mellitus (P=0.04) and insulin resistance (P<0.001). During 12.6 years of follow-up, 174 subjects (4%) developed new-onset diabetes mellitus. The odds of developing diabetes mellitus increased across increasing quartiles of copeptin, even after additional adjustment for baseline fasting glucose and insulin (adjusted odds ratios, 1.0, 1.37, 1.79, and 2.09; P for trend=0.004). The association with incident diabetes mellitus remained significant in analyses restricted to subjects with fasting whole blood glucose <5.4 mmol/L at baseline (adjusted odds ratios, 1.0, 1.80, 1.92, and 3.48; P=0.001).

CONCLUSIONS

Elevated copeptin predicts increased risk for diabetes mellitus independently of established clinical risk factors, including fasting glucose and insulin. These findings could have implications for risk assessment, novel antidiabetic treatments, and metabolic side effects from arginine vasopressin system modulation.

Vitamins B2 and B6 and genetic polymorphisms related to one-carbon metabolism as risk factors for gastric adenocarcinoma in the European prospective investigation into cancer and nutrition

B vitamins and polymorphisms in genes coding for enzymes involved in one-carbon metabolism may affect DNA synthesis and methylation and thereby be implicated in carcinogenesis. Previous data on vitamins B2 and B6 and genetic polymorphisms other than those involving MTHFR as risk factors for gastric cancer (GC) are sparse and inconsistent. In this case-control study nested within the European Prospective Investigation into Cancer and Nutrition cohort, cases (n = 235) and controls (n = 601) were matched for study center, age, sex, and time of blood sampling. B2 and B6 species were measured in plasma, and the sum of riboflavin and flavin mononucleotide was used as the main exposure variable for vitamin B2 status, whereas the sum of pyridoxal 5'-phosphate, pyridoxal, and 4-pyridoxic acid was used to define vitamin B6 status. In addition, we determined eight polymorphisms related to one-carbon metabolism. Relative risks for GC risk were calculated with conditional logistic regression, adjusted for Helicobacter pylori infection status and smoking status. Adjusted relative risks per quartile (95% confidence interval, P(trend)) were 0.85 (0.72-1.01, 0.06) for vitamin B2 and 0.78 (0.65-0.93, <0.01) for vitamin B6. Both relations were stronger in individuals with severe chronic atrophic gastritis. The polymorphisms were not associated with GC risk and did not modify the observed vitamin-cancer associations. In summary, results from this large European cohort study showed an inverse association between vitamin B2 and GC risk, which is borderline significant, and a significant inverse association between vitamin B6 and GC risk.

Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study

OBJECTIVE

Dietary linoleic acid, an n-6 polyunsaturated fatty acid, is metabolised to arachidonic acid, a component of colonocyte membranes. Metabolites of arachidonic acid have pro-inflammatory properties and are increased in the mucosa of patients with ulcerative colitis. The aim of this investigation was to conduct the first prospective cohort study investigating if a high dietary intake of linoleic acid increases the risk of developing incident ulcerative colitis.

DESIGN AND SETTING

Dietary data from food frequency questionnaires were available for 203 193 men and women aged 30-74 years, resident in the UK, Sweden, Denmark, Germany or Italy and participating in a prospective cohort study, the European Prospective Investigation into Cancer and Nutrition (EPIC). These participants were followed up for the diagnosis of ulcerative colitis. Each case was matched with four controls and the risk of disease calculated by quartile of intake of linoleic acid adjusted for gender, age, smoking, total energy intake and centre.

RESULTS

A total of 126 participants developed ulcerative colitis (47% women) after a median follow-up of 4.0 years (range, 1.7-11.3 years). The highest quartile of intake of linoleic acid was associated with an increased risk of ulcerative colitis (odds ratio (OR) = 2.49, 95% confidence interval (CI) = 1.23 to 5.07, p = 0.01) with a significant trend across quartiles (OR = 1.32 per quartile increase, 95% CI = 1.04 to 1.66, p = 0.02 for trend).

CONCLUSIONS

The data support a role for dietary linoleic acid in the aetiology of ulcerative colitis. An estimated 30% of cases could be attributed to having dietary intakes higher than the lowest quartile of linoleic acid intake.

A gene score of nine LDL and HDL regulating genes is associated with fluvastatin-induced cholesterol changes in women

While conventional pharmacogenetic studies have considered single gene effects, we tested if a genetic score of nine LDL- and HDL-associated single nucleotide polymorphisms, previously shown to predict cardiovascular disease, is related to fluvastatin-induced lipid change. In patients with asymptomatic plaque in the right carotid artery, thus candidates for statin therapy, we related score LDL [APOB(rs693), APOE(rs4420638), HMGCR(rs12654264), LDLR(rs1529729), and PCSK9(rs11591147)] and score HDL [ABCA1(rs3890182), CETP(rs1800775), LIPC(rs1800588), and LPL(rs328)] as well as the combined score LDL+HDL to fluvastatin-induced LDL reduction (+/- metoprolol) (n = 395) and HDL increase (n = 187) following 1 year of fluvastatin treatment. In women, an increasing number of unfavorable alleles (i.e., alleles conferring higher LDL and lower HDL) of score LDL+HDL (P = 0.037) and of score LDL (P = 0.023) was associated with less pronounced fluvastatin-induced LDL reduction. Furthermore, in women, both score LDL+HDL (P = 0.001) and score HDL (P = 0.022) were directly correlated with more pronounced fluvastatin-induced HDL increase, explaining 5.9-11.6% of the variance in treatment response in women. There were no such associations in men. This suggests that a gene score based on variation in nine different LDL- and HDL-associated genes is of importance for the magnitude of fluvastatin HDL increase in women with asymptomatic plaque in the carotid artery.

Ion mobility analysis of lipoprotein subfractions identifies three independent axes of cardiovascular risk

OBJECTIVE

Whereas epidemiological studies show that levels of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) predict incident cardiovascular disease (CVD), there is limited evidence relating lipoprotein subfractions and composite measures of subfractions to risk for CVD in prospective cohort studies.

METHODS AND RESULTS

We tested whether combinations of lipoprotein subfractions independently predict CVD in a prospective cohort of 4594 initially healthy men and women (the Malmö Diet and Cancer Study, mean follow-up 12.2 years, 377 incident cardiovascular events). Plasma lipoproteins and lipoprotein subfractions were measured at baseline with a novel high-resolution ion mobility technique. Principal component analysis (PCA) of subfraction concentrations identified 3 major independent (ie, zero correlation) components of CVD risk, one representing LDL-associated risk, a second representing HDL-associated protection, and the third representing a pattern of decreased large HDL, increased small/medium LDL, and increased triglycerides. The last corresponds to the previously described "atherogenic lipoprotein phenotype." Several genes that may underlie this phenotype-CETP, LIPC, GALNT2, MLXIPL, APOA1/A5, LPL-are suggested by SNPs associated with the combination of small/medium LDL and large HDL.

CONCLUSIONS

PCA on lipoprotein subfractions yielded three independent components of CVD risk. Genetic analyses suggest these components represent independent mechanistic pathways for development of CVD.

Orthostatic hypotension predicts all-cause mortality and coronary events in middle-aged individuals (The Malmo Preventive Project)

Aims

Orthostatic hypotension (OH) has been linked to increased mortality and incidence of cardiovascular disease in various risk groups, but determinants and consequences of OH in the general population are poorly studied.

Methods and results

Prospective data of the Swedish ‘Malmö Preventive Project’ (n = 33 346, 67.3% men, mean age 45.7 ± 7.4 years, mean follow-up 22.7 ± 6.0 years) were analysed. Orthostatic hypotension was found in 6.2% of study participants and was associated with age, female gender, hypertension, antihypertensive treatment, increased heart rate, diabetes, low BMI, and current smoking. In Cox regression analysis, individuals with OH had significantly increased all-cause mortality (in particular those aged less than 42 years) and coronary event (CE) risk. Mortality and CE risk were distinctly higher in those with systolic blood pressure (BP) fall ≥30 mmHg [hazard ratio (HR): 1.6, 95% CI 1.3–1.9, P < 0.0001 and 1.6, 95% CI 1.2–2.1, P = 0.001] and diastolic BP fall ≥15 mmHg (HR: 1.4, 95% CI 1.1–1.9, P = 0.024 and 1.7, 95% CI 1.1–2.5, P = 0.01). In addition, impaired diastolic BP response had relatively greater impact (per mmHg) on CE incidence than systolic reaction.

Conclusion

Orthostatic hypotension can be detected in ∼6% of middle-aged individuals and is often associated with such comorbidities as hypertension or diabetes. Presence of OH increases mortality and CE risk, independently of traditional risk factors. Although both impaired systolic and diastolic responses predict adverse events, the diastolic impairment shows stronger association with coronary disease.

Assessing the effect of interaction between an FTO variant (rs9939609) and physical activity on obesity in 15,925 Swedish and 2,511 Finnish adults

AIMS/HYPOTHESIS

Recent reports have suggested that genotypes at the FTO locus interact with physical activity to modify levels of obesity-related traits. We tested this hypothesis in two non-diabetic population-based cohorts, the first from southern Sweden and the second from the Botnia region of western Finland.

METHODS

In total 2,511 Finnish and 15,925 Swedish non-diabetic middle-aged adults were genotyped for the FTO rs9939609 variant. Physical activity was assessed by questionnaires and standard clinical procedures were conducted, including measures of height and weight and glucose regulation. Tests of gene x physical activity interaction were performed using linear interaction effects to determine whether the effect of this variant on BMI is modified by physical activity.

RESULTS

The minor A allele at rs9939609 was associated with higher BMI in both cohorts, with the per allele difference in BMI being about 0.13 and 0.43 kg/m(2) in the Swedish and Finnish cohorts, respectively (p < 0.0001). The test of interaction between physical activity and the rs9939609 variant on BMI was not statistically significant after controlling for age and sex in either cohort (Sweden: p = 0.71, Finland: p = 0.18).

CONCLUSIONS/INTERPRETATION

The present report does not support the notion that physical activity modifies the effects of the FTO rs9939609 variant on obesity risk in the non-diabetic Swedish or Finnish adults studied here.

Novel and conventional biomarkers for prediction of incident cardiovascular events in the community

CONTEXT

Prior studies have demonstrated conflicting results regarding how much information novel biomarkers add to cardiovascular risk assessment.

OBJECTIVE

To evaluate the utility of contemporary biomarkers for predicting cardiovascular risk when added to conventional risk factors.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study of 5067 participants (mean age, 58 years; 60% women) without cardiovascular disease from Malmö, Sweden, who attended a baseline examination between 1991 and 1994. Participants underwent measurement of C-reactive protein (CRP), cystatin C, lipoprotein-associated phospholipase 2, midregional proadrenomedullin (MR-proADM), midregional proatrial natriuretic peptide, and N-terminal pro-B-type natriuretic peptide (N-BNP) and underwent follow-up until 2006 using the Swedish national hospital discharge and cause-of-death registers and the Stroke in Malmö register for first cardiovascular events (myocardial infarction, stroke, coronary death).

MAIN OUTCOME MEASURES

Incident cardiovascular and coronary events.

RESULTS

During median follow-up of 12.8 years, there were 418 cardiovascular and 230 coronary events. Models with conventional risk factors had C statistics of 0.758 (95% confidence interval [CI], 0.734 to 0.781) and 0.760 (0.730 to 0.789) for cardiovascular and coronary events, respectively. Biomarkers retained in backward-elimination models were CRP and N-BNP for cardiovascular events and MR-proADM and N-BNP for coronary events, which increased the C statistic by 0.007 (P = .04) and 0.009 (P = .08), respectively. The proportion of participants reclassified was modest (8% for cardiovascular risk, 5% for coronary risk). Net reclassification improvement was nonsignificant for cardiovascular events (0.0%; 95% CI, -4.3% to 4.3%) and coronary events (4.7%; 95% CI, -0.76% to 10.1%). Greater improvements were observed in analyses restricted to intermediate-risk individuals (cardiovascular events: 7.4%; 95% CI, 0.7% to 14.1%; P = .03; coronary events: 14.6%; 95% CI, 5.0% to 24.2%; P = .003). However, correct reclassification was almost entirely confined to down-classification of individuals without events rather than up-classification of those with events.

CONCLUSIONS

Selected biomarkers may be used to predict future cardiovascular events, but the gains over conventional risk factors are minimal. Risk classification improved in intermediate-risk individuals, mainly through the identification of those unlikely to develop events.

Previously associated type 2 diabetes variants may interact with physical activity to modify the risk of impaired glucose regulation and type 2 diabetes: a study of 16,003 Swedish adults

OBJECTIVE

Recent advances in type 2 diabetes genetics have culminated in the discovery and confirmation of multiple risk variants. Two important and largely unanswered questions are whether this information can be used to identify individuals most susceptible to the adverse consequences of sedentary behavior and to predict their response to lifestyle intervention; such evidence would be mechanistically informative and provide a rationale for targeting genetically susceptible subgroups of the population.

RESEARCH DESIGN AND METHODS

Gene x physical activity interactions were assessed for 17 polymorphisms in a prospective population-based cohort of initially nondiabetic middle-aged adults. Outcomes were 1) impaired glucose regulation (IGR) versus normal glucose regulation determined with either fasting or 2-h plasma glucose concentrations (n = 16,003), 2) glucose intolerance (in mmol/l, n = 8,860), or 3) incident type 2 diabetes (n = 2,063 events).

RESULTS

Tests of gene x physical activity interactions on IGR risk for 3 of the 17 polymorphisms were nominally statistically significant:CDKN2A/B rs10811661 (P(interaction) = 0.015), HNF1B rs4430796 (P(interaction) = 0.026), and PPARG rs1801282 (P(interaction) = 0.04). Consistent interactions were observed for the CDKN2A/B (P(interaction) = 0.013) and HNF1B (P(interaction) = 0.0009) variants on 2-h glucose concentrations. Where type 2 diabetes was the outcome, only one statistically significant interaction effect was observed, and this was for the HNF1B rs4430796 variant (P(interaction) = 0.0004). The interaction effects for HNF1B on IGR risk and incident diabetes remained significant after correction for multiple testing (P(interaction) = 0.015 and 0.0068, respectively).

CONCLUSIONS

Our observations suggest that the genetic predisposition to hyperglycemia is partially dependent on a person's lifestyle.

Systematically missing confounders in individual participant data meta-analysis of observational cohort studies

One difficulty in performing meta-analyses of observational cohort studies is that the availability of confounders may vary between cohorts, so that some cohorts provide fully adjusted analyses while others only provide partially adjusted analyses. Commonly, analyses of the association between an exposure and disease either are restricted to cohorts with full confounder information, or use all cohorts but do not fully adjust for confounding. We propose using a bivariate random-effects meta-analysis model to use information from all available cohorts while still adjusting for all the potential confounders. Our method uses both the fully adjusted and the partially adjusted estimated effects in the cohorts with full confounder information, together with an estimate of their within-cohort correlation. The method is applied to estimate the association between fibrinogen level and coronary heart disease incidence using data from 154 012 participants in 31 cohorts.† Copyright © 2009 John Wiley & Sons, Ltd.

Genome-wide association study identifies eight loci associated with blood pressure

Elevated blood pressure is a common, heritable cause of cardiovascular disease worldwide. To date, identification of common genetic variants influencing blood pressure has proven challenging. We tested 2.5m genotyped and imputed SNPs for association with systolic and diastolic blood pressure in 34,433 subjects of European ancestry from the Global BPgen consortium and followed up findings with direct genotyping (N≤71,225 European ancestry, N=12,889 Indian Asian ancestry) and in silico comparison (CHARGE consortium, N=29,136). We identified association between systolic or diastolic blood pressure and common variants in 8 regions near the CYP17A1 (P=7×10⁻²⁴), CYP1A2 (P=1×10⁻²³), FGF5 (P=1×10⁻²¹), SH2B3 (P=3×10⁻¹⁸), MTHFR (P=2×10⁻¹³), c10orf107 (P=1×10⁻⁹), ZNF652 (P=5×10⁻⁹) and PLCD3 (P=1×10⁻⁸) genes. All variants associated with continuous blood pressure were associated with dichotomous hypertension. These associations between common variants and blood pressure and hypertension offer mechanistic insights into the regulation of blood pressure and may point to novel targets for interventions to prevent cardiovascular disease.

Immune responses against fibronectin modified by lipoprotein oxidation and their association with cardiovascular disease

OBJECTIVES

Accumulation and subsequent oxidation of LDL in the arterial wall are considered as key events in the development of atherosclerosis. We have investigated the possibility that LDL oxidation results in release of aldehydes that modify surrounding matrix proteins and that this may target immune responses against the plaque extracellular matrix and modulate the disease progression.

RESULTS

Using custom-made ELISAs we demonstrate that human plasma contains autoantibodies against aldehyde-modified fibronectin (FN) and to a lesser extent also other extracellular matrix proteins including collagen type I, type III, and tenascin-C. Immunohistochemistry and western blot analysis showed that aldehyde-modified FN is present in human atherosclerotic plaques and that aldehydes generated by oxidation of LDL formed adducts with FN in vitro. We also demonstrate that aldehyde-modification of FN results in a loss of its ability to promote basal secretion of cytokines and growth factors from cultured macrophages without affecting the ability of the cells to respond to stimulation with LPS. A prospective clinical study demonstrated that subjects that subsequently developed acute myocardial infarction or sudden cardiac death had lower baseline levels of autoantibodies against aldehyde-modified FN than matched controls.

CONCLUSIONS

These observations demonstrate that oxidation of LDL in the arterial wall may lead to aldehyde-modification of surrounding extracellular matrix proteins and that these modifications may affect macrophage function and activate autoimmune responses of pathophysiological importance for the development of atherosclerosis.

Fruit, vegetables, and colorectal cancer risk: the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

A high consumption of fruit and vegetables is possibly associated with a decreased risk of colorectal cancer (CRC). However, the findings to date are inconsistent.

OBJECTIVE

We examined the relation between self-reported usual consumption of fruit and vegetables and the incidence of CRC.

DESIGN

In the European Prospective Investigation into Cancer and Nutrition (EPIC), 452,755 subjects (131,985 men and 320,770 women) completed a dietary questionnaire in 1992-2000 and were followed up for cancer incidence and mortality until 2006. A multivariate Cox proportional hazard model was used to estimate adjusted hazard ratios (HRs) and 95% CIs.

RESULTS

After an average follow-up of 8.8 y, 2,819 incident CRC cases were reported. Consumption of fruit and vegetables was inversely associated with CRC in a comparison of the highest with the lowest EPIC-wide quintile of consumption (HR: 0.86; 95% CI: 0.75, 1.00; P for trend = 0.04), particularly with colon cancer risk (HR: 0.76; 95% CI: 0.63, 0.91; P for trend < 0.01). Only after exclusion of the first 2 y of follow-up were these findings corroborated by calibrated continuous analyses for a 100-g increase in consumption: HRs of 0.95 (95% CI: 0.91, 1.00; P = 0.04) and 0.94 (95% CI: 0.89, 0.99; P = 0.02), respectively. The association between fruit and vegetable consumption and CRC risk was inverse in never and former smokers, but positive in current smokers. This modifying effect was found for fruit and vegetables combined and for vegetables alone (P for interaction < 0.01 for both).

CONCLUSIONS

These findings suggest that a high consumption of fruit and vegetables is associated with a reduced risk of CRC, especially of colon cancer. This effect may depend on smoking status.

Renal function in normo- and hypertensive 50-year-old males

Renal function, measure as glomerular filtration rate (GFR), sodium excretion and osmolality after thirst, has been determined in untreated (n=35) and treated (n=22) hypertensives and in a reference group (n=80), all derived from a random population sample of 50-year-old men. Renal function was related to casual and resting BP and to relative body weight. Hypertension was defined as SBP greater than 175 or DBP greater than 115 mmHg on two separate occasions or current antihypertensive treatment. Mean GFR was 100 +/- 11.7 ml/min in the reference group and significantly lower, 94 +/- 15.7 ml/min, in the hypertension group. In the hypertension group, 20% had a reduced GFR, although the standard diagnostic procedure, serum creatinine, demonstrated only 4%. Hypertensives with reduced GFR were characterized by higher BP, lower urinary sodium excretion, reversed diurnal rhythm of salt and water excretion and a higher relative body weight, which was, however, explained by the correlation of BP to relative body weight. GFR was negatively correlated to DBP at rest and positively correlated to urinary sodium excretion. Untreated hypertensives with persistent high BP after rest and lower GFR, lower urinary sodium excretion and reversed diurnal rhythm of salt and water excretion, indicating high renal resistance. The results suggest that subjects with relatively severe hypertension as judged by BP and renal function have an increased renal vascular resistance.

Blood pressure in relation to the renin-angiotensin-aldosterone system

The relationship between blood pressure (BP) and the renin-angiotensin-aldosterone system was studied in a stratified random sample (n=120) of 49-year-old men selected from a BP screening and covering a wide range of BPs. Only subjects not on antihypertensive treatment were included. None had malignant or secondary hypertension. Plasma renin activity, plasma concentrations of angiotensin II, aldosterone, sodium, potassium and noradrenaline and the 24-hour urinary excretions of sodium, cortisol and noradrenaline were determined. Of these variables, only p-aldosterone was significantly correlated wtih BP, both in the whole study group (R=0.22, p less than 0.02, n=119) and in the subjects with the highest BP range (R=0.36, p less than 0.02, n=30). Of the clinical groups compared, the hypertensive subjects had significantly higher mean p-aldosterone than the borderline and normotensive subjects. Multiple regression analysis showed that the 24-hour urinary excretion of noradrenaline was the factor most strongly correlated to p-aldosterone, suggesting that the sympathetic nervous system might stimulate aldosterone secretion. Our findings indicate that aldosterone may be of importance for the development and maintenance of essential hypertension.

The Skaraborg hypertension project. I. The prevalence of hypertension

The prevalence of hypertension in the age group 40-69 in the County of Skaraborg, Sweden (265000 inhabitants) was estimated using diagnostic criteria commonly accepted in Sweden in recent years. The prevalence was higher than expected (16%) and most of the patients (80%) were previously identified and undergoing treatment. The quantitative aspect of hypertension was even more impressive in the ages above 69 years. Eighteen per cent of the men and 33% of the women aged 75 years were on antihypertensive medication. An unexpectedly large proportion of the population had a borderline pressure requiring further follow-up (16%). It is concluded that quantitative aspects must be taken into consideration when planning hypertension care and deciding diagnostic criteria.

Changes in intraerythrocyte content and transmembrane fluxes of sodium during salt loading in subjects with and without family history of hypertension

We studied 17 young normotensive men with family history of hypertension (H) in two generations (father and grandfather) and 17 age matched control subjects (C) with respect to intraerythrocyte sodium (IeNa), sodium influx, and rate of sodium efflux. The investigation was done during ordinary salt intake and after four week's salt load. H had a significantly higher IeNa (9.5 +/- 0.4 mmol/l) compared to C (8.2 +/- 0.3 mmol/l), p less than 0.01. After salt loading H decreased significantly to 8.1 +/- 0.3 mmol/l while C did not change significantly (7.6 +/- 0.3 mmol/l). There was no significant difference between H and C in Na influx either on normal or on high salt intake. The rate constant for Na efflux was significantly lower on normal salt intake in H (0.0038 +/- 0.0003 vs 0.0050 +/- 0.0004 min-1, p less than 0.05). High salt intake increased the efflux rate constant significantly in H (0.0048 +/- 0.0003 min-1, p less than 0.05), while control subjects showed no difference (0.0053 +/- 0.0004 min-1) compared to pre-salt conditions. Our results suggest that young men with heredity for hypertension have a higher intraerythrocyte Na-content secondary to a lower rate of Na efflux. The Na influx did not differ between the two groups probably indicating an unchanged permeability for sodium in subjects with a family history of hypertension.

Effects of labetalol and propranolol on the peripheral circulation in hypertensive patients

Eleven patients with essential hypertension participated in a double-blind cross-over comparison of labetalol (L) and propranolol (P). Each drug was given for 5--8 weeks. The dose reducing the supine diastolic blood pressure when given b.d. to or below 90 mm Hg was titrated out. At the end of each period, isometric exercise (sustained handgrip) and calf plethysmography were performed. L (mean daily dose 636 mg) was slightly more effective in lowering supine and standing blood pressure than P (mean dose 276 mg). There was no significant difference between the drugs in their effect on the blood-pressure response to handgrip. However, compared with no treatment, L attenuated the blood-pressure rise at near-maximal handgrip; this has not been reported with other beta-blockers. Resting vascular resistance and basal vascular tone were significantly lower (20%, p less than 0.05) during treatment with labetalol than when the patients were taking propranolol. - The differences may be explained by the alpha-receptorblocking action of labetalol.

Alcoholic intemperance, coronary heart disease and mortality in middle-aged Swedish men

High alcohol consumption is one of the major risk indicators for premature death in middle-aged men. An indicator of alcohol abuse--registration with the social authorities for alcoholic problems--was used to evaluate the role of alcohol in relation to general and cause-specific mortality in a general population sample. Altogether 1,116 men (11%) out of a total population of 10,004 men were registered for alcoholic problems. Total mortality during 11.8 years' follow-up was 10.4% among the non-registered men, compared to 20.5% among men with occasional convictions for drunkenness and 29.6% among heavy abusers. Fatal cancer as a whole was not independently associated with alcohol abuse, but oropharyngeal and oesophageal cancers together were seven times more common in the alcohol-registered groups. Total coronary heart disease (CHD) was significantly and independently associated with alcohol abuse, but nearly all the excess CHD mortality among the alcohol-registered men could be attributed to sudden coronary death. Cases with definite recent myocardial infarction were not more common in the alcoholic population. A combined effect of coronary arteriosclerosis and heart muscle damage secondary to alcohol abuse is suggested. Other causes of death strongly associated with registration for alcohol abuse include pulmonary embolism, pneumonia and peptic ulcer, as well as death from liver cirrhosis and alcoholism. Of the excess mortality among alcohol-registered subjects, 20.1% could be attributed to CHD, 18.1% to violent death, 13.6% to alcoholism without another diagnosis and 11.1% to liver cirrhosis.

Significant relationship between renin suppression and atrial natriuretic peptide (alpha-hANP) during volume loading in hypertensive men

We have studied eight men with moderate hypertension to determine the atrial natriuretic peptide (alpha-hANP) response to acute volume expansion. Rapid infusion of 1,000 ml 0.9% saline (10-20 min) caused an increase in central venous pressure (4.7 +/- 1.6 cmH2O) while blood pressure and pulse pressure (arterial baroreceptor load) did not change. Stroke volume and heart rate were not affected by the volume load but plasma renin activity (PRA) was significantly suppressed (from 0.83 +/- 0.14 to 0.68 +/- 0.34 microgram AI I/ml-h; p less than 0.01). A significant hemodilution was also observed. Renal sodium excretion was significantly increased. Arterial alpha-hANP increased significantly from 21.1 +/- 6.1 to 30.5 +/- 4.0 pmol/l (p less than 0.02) during volume expansion. There was a significant correlation between corrected plasma volume increase (urine volume subtracted from the infused volume) and alpha-hANP plasma elevation (r = 0.78; p less than 0.05). There was also a significant negative correlation between changes alpha-hANP and PRA (r = -0.78, p less than 0.05). We conclude that only moderate volume loading in human hypertensives is a mechanism for increase in plasma alpha-hANP levels. The significant negative correlation between changes in alpha-hANP and PRA suggests that alpha-hANP may be the humoral factor at least partly responsible for suppression of renin in hypertensive man. Since increased fluid volume also affects sympathetic renal efferents as well as vasopressin secretion, our observed relationship between volume load and renin may well be related also to such mechanisms.

The role of salt in hypertension

Epidemiological data indicate a weak but significant positive correlation between the level of salt intake and blood pressure. It is unclear how this relationship is mediated but some studies indicate that heredity for hypertension is associated with an increased sensitivity to salt. Decrease of the salt intake decreases blood pressure in established hypertension and should be used as a therapeutic adjuvant in mild uncomplicated hypertension much more often than is now the case. Increased salt intake in young subjects with or without heredity for hypertension does not seem to increase the blood pressure during a 4-12 week load. Increased salt intake in middle-aged men, on the other hand, seem to induce a blood pressure increase irrespective of the presence or absence of a positive family history. The sensitivity to a high salt intake might thus be associated with aging. Increase of the salt intake from the normal level seems to induce an increase in sympathetic nervous activity. The interplay between the level of salt intake and sympathetic nervous activity should be studied in more detail.