Maximal oxygen uptake (VO2max) is an important, independent predictor of cardiovascular health and mortality. Despite this, it is rarely measured in clinical practice. The aim of this study was to ...create and evaluate a submaximal cycle ergometry test based on change in heart rate (HR) between a lower standard work rate and an individually chosen higher work rate. In a mixed population (n = 143) with regard to sex (55% women), age (21–65 years), and activity status (inactive to highly active), a model included change in HR per unit change in power, sex, and age for the best estimate of VO2max. The association between estimated and observed VO2max for the mixed sample was r = 0.91, standard error of estimate = 0.302 L/min, and mean measured VO2max = 3.23 L/min. The corresponding coefficient of variation was 9.3%, a significantly improved precision compared with one of the most commonly used submaximal exercise tests, the Åstrand test, which in the present study was estimated to be 18.1%. Test–retest reliability analysis over 1 week revealed no mean difference in the estimated VO2max (−0.02 L/min, 95% confidence interval: −0.07–0.03). The new test is low‐risk, easily administered, and valid for a wide capacity range, and is therefore suitable in situations as health evaluations in the general population.
Aims/hypothesis Fatty acid desaturases introduce double bonds into growing fatty acid chains. The key desaturases in humans are Δ⁵-desaturase (D5D), Δ⁶-desaturase (D6D) and stearoyl-CoA desaturase ...(SCD). Animal and human data implicate hepatic desaturase activities in insulin resistance, obesity and dyslipidaemia. However, the role of desaturase activity in adipose tissue is uncertain. We therefore evaluated relationships between adipose mRNA expression, estimated desaturase activities (fatty acid ratios) in adipose tissue and insulin resistance. Methods Subcutaneous adipose tissue mRNA expression of D5D (also known as FADS1), D6D (also known as FADS2) and SCD was determined in 75 individuals representative of the study population of 294 healthy 63-year-old men. Desaturation indexes (product/substrate fatty acid ratios) were generated from adipose tissue fatty acid composition in all individuals. Insulin resistance was defined as the upper quartile of the updated homeostasis model assessment (HOMA-2) index. Results The relevant desaturation indexes (16:1/16:0, 18:1/18:0, 20:4/20:3 and 18:3/18:2) reflected expression of SCD, but not of D5D or D6D in adipose tissue. Insulin-resistant individuals had a higher adipose tissue 18:1/18:0, but not 16:1/16:0 ratio than insulin-sensitive individuals. Individuals with a high adipose tissue 18:1/18:0 ratio were 4.4-fold (95% CI 1.8-11.8) more likely to be insulin resistant threefold (95% CI 1.1-8.6) after adjustment for waist circumference and plasma triacylglycerol. In a multiple regression model predicting HOMA-2, the independent effect of the 18:1/18:0 ratio was borderline (p = 0.086). Conclusions/interpretation Adipose tissue desaturation indexes of SCD reflect the expression of the gene encoding the enzyme in this tissue. Elevated SCD activity within adipose tissue is closely coupled to the development of insulin resistance.
. Mälarstig A, Silveira A, Wågsäter D, Öhrvik J, Bäcklund A, Samnegård A, Khademi M, Hellenius M‐L, Leander K, Olsson T, Uhlén M, de Faire U, Eriksson P, Hamsten A (Karolinska University Hospital; ...Institute of Environmental Medicine, Karolinska Institutet, Stockholm; KTH‐Royal Institute of Technology, Stockholm, Sweden). Plasma CD93 concentration is a potential novel biomarker for coronary artery disease. J Intern Med 2011; 270: 229–236.
Objectives. A common nonsynonymous single nucleotide polymorphism (SNP) in the CD93 gene (rs3746731, Pro541Ser) has been associated with risk of coronary artery disease (CAD). CD93 is a transmembrane glycoprotein, which is detectable in soluble form in human plasma. We investigated whether the concentration of soluble CD93 in plasma is related to risk of myocardial infarction (MI) and CAD, using a case–control study of premature MI (n = 764) and a nested case–control analysis of a longitudinal cohort study of 60‐year‐old subjects (analysis comprising 844 of 4232 subjects enrolled at baseline). In addition, SNPs in the CD93 gene were studied in relation to plasma CD93 concentration and CD93 mRNA expression.
Methods and Results. A sensitive and specific enzyme‐linked immunosorbent assay was established for determination of the plasma CD93 concentration. Subjects were divided into three groups according to tertiles of the distribution of CD93 concentration. Lower odds ratios for risk of MI and incidence of CAD were observed in the middle CD93 tertile (142–173 μg L−1): odds ratio (95% confidence interval), 0.69 (0.49–0.97) and 0.61 (0.40–0.94), respectively. These associations were independent of traditional CAD risk factors. The minor allele of a SNP in the 3′ untranslated region of CD93 (rs2749812) was associated with increased plasma CD93 concentrations (P = 0.03) and increased CD93 mRNA expression levels (P = 0.02).
Conclusion. The results of the present study suggest that the concentration of soluble CD93 in plasma is a potential novel biomarker for CAD, including MI.
The purpose of this study was to investigate the importance of enjoyment of exercise in a health care‐based intervention aimed at promoting physical exercise in primary health care patients. In a ...controlled study design, the intervention group was offered a wide range of group exercises over 3 months, followed by support in designing their own exercise program. The control group received usual care. Enjoyment of exercise and exercise level were measured. Associations between enjoyment and exercise level were analyzed using Spearman's rank correlation coefficients. Changes in enjoyment between and within study groups were analyzed by the independent and paired t‐test. Associations were found between enjoyment and exercise level (r=0.36, P<0.01), as well as between changes in enjoyment and changes in exercise level (r=0.34, P<0.01). At the 12‐month follow‐up, enjoyment of exercise was 25% higher in the intervention group than in the control group (P<0.01). In this group of primary health care patients, enjoyment of exercise was associated with exercise level. Enjoyment of exercise seems to be a mediator of exercise level. Furthermore, health care‐based interventions seem to be able to affect enjoyment of exercise. Enjoyment of exercise may be important for the long‐term effectiveness, of health care‐based interventions.
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Objectives. To examine the relationship between cardiovascular fitness (VO2max) and abdominal obesity (waist circumference) and individual cardiovascular disease (CVD) risk factors, as well as a ...clustered risk factor profile, and to study the impact of gender, age and smoking on these relationships.
Design. Cross‐sectional.
Setting. Astrand Laboratory of Work Physiology, Swedish School of Sport and Health Sciences, Stockholm, Sweden.
Subjects. Men (n = 781) and women (n = 890) from two random population‐based samples of Swedish women and men aged 20 to 65 years.
Main outcomes. Odds ratios.
Results. Each unit of higher fitness was associated with a decrease in all individual risk factors ranging from 2% to 4% independent of waist circumference, each unit of higher waist circumference was associated with an increased risk ranging from 2% to 5% independent of fitness. For clustering of three or more of the risk factors, each unit of fitness was associated with a 5% decrease in risk and each unit of waist circumference with a 5% increase in risk. The clustered risk was higher in unfit participants who were older or smoked daily, regardless of waist circumference. Obese participants were at higher risk if they were men or older, regardless of fitness level. However, neither a higher fitness level nor lean status reduced the risk associated with smoking.
Conclusions. Higher fitness and lower waist circumference are each independently associated to a similar extent with a lower CVD risk. Simultaneous evaluation of both fitness and abdominal obesity status in clinical practice is important.
Aims Prospective studies indicate that apolipoprotein measurements predict coronary heart disease (CHD) risk; however, evidence is conflicting, especially in the US. Our aim was to assess whether ...measurements of apolipoprotein B (apoB) and apolipoprotein A-I (apoA-I) can improve the ability to predict CHD death beyond what is possible based on traditional cardiovascular (CV) risk factors and clinical routine lipid measurements. Methods and results We analysed prospectively associations of apolipoprotein measurements, traditional CV risk factors, and clinical routine lipid measurements with CHD mortality in a multi-ethnic representative subset of 7594 US adults (mean age 45 years; 3881 men and 3713 women, median follow-up 124 person-months) from the Third National Health and Nutrition Examination Survey mortality study. Multiple Cox-proportional hazards regression was applied. There were 673 CV deaths of which 432 were from CHD. Concentrations of apoB hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.09–3.61, apoA-I (HR 0.48, 95% CI 0.27–0.85) and total cholesterol (TC) (HR 1.17, 95% CI 1.02–1.34) were significantly related to CHD death, whereas high density lipoprotein cholesterol (HDL-C) (HR 0.68, 95% CI 0.45–1.05) was borderline significant. Both the apoB/apoA-I ratio (HR 2.14, 95% CI 1.11–4.10) and the TC/HDL-C ratio (HR 1.10, 95% CI 1.04–1.16) were related to CHD death. Only apoB (HR 2.01, 95% CI 1.05–3.86) and the apoB/apoA-I ratio (HR 2.09, 95% CI 1.04–4.19) remained significantly associated with CHD death after adjusting for CV risk factors. Conclusion In the US population, apolipoprotein measurements significantly predict CHD death, independently of conventional lipids and other CV risk factors (smoking, dyslipidaemia, hypertension, obesity, diabetes and C-reactive protein). Furthermore, the predictive ability of apoB alone to detect CHD death was better than any of the routine clinical lipid measurements. Inclusion of apolipoprotein measurements in future clinical guidelines should not be discarded.
The purpose of this study was to analyse the association of leisure-time physical activity of different intensities at baseline, and cardiovascular disease incidence, cardiovascular disease mortality ...and all-cause mortality in a population-based sample of 60-year-old men and women with and without established metabolic syndrome, for more than 20 years of follow-up. A secondary aim was to study which cardiometabolic factors may mediate the association between physical activity and long-term outcomes.
A total of 3693 participants (53% women) underwent physical examination and laboratory tests, completed an extensive questionnaire at baseline 1997-1999 and were followed until their death or until 31 December 2017. First-time cardiovascular disease events and death from any cause were ascertained through regular examinations of national registers.
Metabolic syndrome prevalence was 23.0%. In metabolic syndrome participants, light physical activity attenuated cardiovascular disease incidence (hazard ratio = 0.71; 95% confidence interval 0.50-1.00) compared to sedentary (reference) after multi-adjustment. Moderate/high physical activity was inversely associated with both cardiovascular disease and all-cause mortality, but became non-significant after multi-adjustment. Sedentary non-metabolic syndrome participants had lower cardiovascular disease incidence (0.47; 0.31-0.72) but not significantly different cardiovascular disease (0.61; 0.31-1.19) and all-cause mortality (0.92; 0.64-1.34) compared to sedentary metabolic syndrome participants. Both light and moderate/high physical activity were inversely associated with cardiovascular disease and all-cause mortality in non-metabolic syndrome participants (p<0.05). There were significant variations in several central cardiometabolic risk factors with physical activity level in non-metabolic syndrome participants. Fibrinogen mediated the protective effects of physical activity in non-metabolic syndrome participants.
Physical activity of different intensities attenuated cardiovascular risk and mortality in 60-year old men and women with metabolic syndrome during a 20-year follow-up.
Alcohol consumption is considered to affect circulating fatty acids (FAs) but knowledge about specific associations is limited. We aimed to assess the relation between alcohol consumption and serum ...FAs in 60-year-old Swedish men and women.
In a random sample of 1917 men and 2058 women residing in Stockholm county, cross-sectional associations between different categories of alcohol consumption and FAs were assessed using linear regression; β1 coefficients with 95% confidence interval (CI) were calculated. Self-reported alcohol consumption was categorized as none, low (≤9.9 g/day) (reference), moderate (10−29.9 g/day) and high (≥30 g/day). Moderate alcohol consumption was further subdivided into consumption of beer, wine, liquor and their combinations. Thirteen serum cholesterol ester FAs were measured by gas chromatography and individual FAs were expressed as percentage of total FAs.
Increasing alcohol consumption was associated to linear increase of saturated myristic acid, monounsaturated FAs and n-6 polyunsaturated (PUFA) arachidonic acid, whereas linear decrease was noted for saturated pentadecanoic acid and for n-6 PUFA linoleic acid. With non-linear associations, increasing alcohol consumption also associated to decreased saturated stearic acid, n-6 PUFA dihomo-gamma-linolenic acid, and n-3 PUFA docosahexaenoic acid and increased saturated palmitic acid, n-6 PUFA gamma-linolenic acid and n-3 PUFA eicosapentaenoic acid. Among types of beverages, wine consumption was associated with n-6 PUFA arachidonic acid (β1 0.59; 95% CI: 0.30;0.88) and the n-3 PUFAs eicosapentaenoic acid (β1 0.54; 95% CI: 0.30;0.78), and docosahexaenoic acid (β1 0.06; 95% CI: 0.00;0.12).
These findings may give important basis for further investigations to better understand biological mechanisms behind the dose-dependent associations between alcohol consumption and health outcomes observed in many previous studies.
A diet rich in fruits and vegetables is associated with lowering of blood pressure (BP), but the nutrient(s) responsible for these effects remain unclear. Research suggests that inorganic nitrate ...present in leafy green vegetables is converted into NO in vivo to improve cardiovascular function.
In this study, we evaluated the effect of leafy green vegetables on BP in subjects with elevated BP, with the aim of elucidating if any such effect is related to their high nitrate content.
We enrolled 243 subjects, 50–70 y old, with a clinic systolic BP (SBP) of 130–159 mm Hg. After a 2-wk run-in period on a nitrate-restricted diet the subjects were randomly assigned to receive 1 of the following 3 interventions daily for 5 wk: low-nitrate vegetables + placebo pills, low-nitrate vegetables + nitrate pills (300 mg nitrate), or leafy green vegetables containing 300 mg nitrate + placebo pills. The primary end point measure was the difference in change in 24 h ambulatory SBP between the groups.
A total of 231 subjects (95%) completed the study. The insignificant change in ambulatory SBP (mean ± standard deviation) was −0.6 ± 6.2 mm Hg in the placebo group, −1.2 ± 6.8 mm Hg in the potassium nitrate group, and −0.5 ± 6.6 mm Hg in the leafy green vegetable group. There was no significant difference in change between the 3 groups.
A 5-wk dietary supplementation with leafy green vegetables or pills containing the same amount of inorganic nitrate does not decrease ambulatory SBP in subjects with elevated BP. This trial was registered at clinicaltrials.gov as NCT02916615.
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