Stiffening Our Resolve Against Adult Weight Gain

Effects of fitness and fatness on age-related arterial stiffening in people with type 2 diabetes

People with type 2 diabetes (T2D) are at a greater risk of cardiovascular disease than the general population. Both non-modifiable (age) and modifiable (low aerobic fitness, high body fatness) factors are separately predictive of cardiovascular risk, although they often occur concomitantly. This study aimed to examine the (1) association between age and arterial stiffness, a subclinical marker of cardiovascular risk; and (2) effects of body fatness and aerobic fitness on age-related increases in arterial stiffness in people with T2D. Data from 64 individuals with T2D (age 59.8 ± 8.7 years, 40% female, HbA1c 8.4 ± 1.6%) were included in this cross-sectional analysis. Carotid-femoral pulse wave velocity (cfPWV) was used to quantify arterial stiffness. Aerobic fitness (relative V̇O2peak ) was determined via indirect calorimetry during maximal exercise testing. Central body fatness was determined using waist circumference. Data were analysed using hierarchical multiple regressions. After adjustment for sex and duration of T2D, each one standard deviation (SD) increase in age (8.68 years) was associated with a 0.63 m·s-1 increase in cfPWV (β = 0.416, p = 0.001). Following adjustment for aerobic fitness and body fatness, the standardized β was unchanged (0.417). A one SD increase in waist circumference (13.9 cm) and relative V̇O2peak (5.3 ml·kg-1 ·min-1 ) were associated with a similar magnitude of difference in cfPWV (0.47 m·s-1 and -0.44 m·s-1 , respectively). Therefore, age is a significant correlate of increased arterial stiffness in T2D, with higher aerobic fitness attenuating, and higher body fatness exacerbating, this increase. Interventions aimed at improving cardiovascular outcomes in people with T2D should target both increased aerobic fitness and reduced body fatness.

Dynamic changes in aortic stiffness after substantial weight loss by laparoscopic sleeve gastrectomy in patients with obesity: a 1-year follow-up study

Arterial stiffness has been identified as a powerful and independent risk factor for cardiovascular disease. Obesity is associated with an increased risk of aortic stiffness (AS) and adverse cardiovascular events. Herein, we aimed to evaluate the effects of weight loss after laparoscopic sleeve gastrectomy (LSG) on AS in individuals with morbid obesity by using the transthoracic echocardiography (TTE).A total of 53 patients with obesity (17 males, 36 females) who underwent LSG and did not have any known heart disease were included in the study. The AS parameters were measured with TTE. The demographic and echocardiographic data of the patients were studied before, at 1 month and 12 months after surgery.The mean age of the study group was 34.41±11.62, 68% of whom were female. There were no significant differences in terms of the standard echocardiography and Doppler measurements as compared with preoperative values (all p>0.05). When the elastic parameters of the aorta were compared, no significant differences were detected regarding aortic strain (%) ((16.28±4.11) vs (16.68±4.56), p=(0.998)), distensibility (cm²/dyn) ((6.74±1.78) vs (7.03±2.31), p=(0.997)) and Aortic Stiffness Index values ((10.73±3.84) vs (10.63±3.34), p=0.998) between baseline and first month after surgery. In the 12-month follow-up, it was determined that the aortic strain ((16.28±4.11) vs (22.74±5.79), p≤0.001) and distensibility ((6.74±1.78) vs (10.34±3.059), p<0.001)) values increased at significant levels.Weight loss by LSG improves arterial stiffness parameters in patients with obesity over a 1-year follow-up.

Arterial wall shear rate response to reactive hyperaemia is markedly different between young and older humans

KEY POINTS

The vasodilatory response to reactive hyperaemia is impaired with advancing age, but it is unclear whether this is because of an altered wall shear rate (WSR) stimulus or an altered flow-mediated dilatation (FMD) response. Using new technology that allows detailed WSR measurement, we assessed the WSR-FMD response in healthy older people. Our data show that older people have a markedly altered and diminished WSR response to reactive hyperaemia compared to young people, but reduced WSR alone does not fully explain reduced FMD. In young people, WSR appears to be coupled to FMD but, by age ∼65 years, the arterial vasodilatory response has begun to uncouple from the WSR stimulus. These findings point to the importance and utility of comprehensively characterizing the WSR-FMD response when using reactive hyperaemia to assess vascular function, as well as giving new insight into the age-related alteration in vascular function.

ABSTRACT

The vasodilatory response to reactive hyperaemia is impaired with age, but it is unknown whether this is because of an altered wall shear rate (WSR) stimulus or an altered flow-mediated dilatation (FMD) response to the WSR stimulus. Inherent difficulties in measuring blood flow velocity close to the arterial wall have prevented detailed assessment of the WSR-FMD response. Using an enhanced multigate spectral Doppler ultrasound system (ultrasound advanced open platform), we aimed to produce new data on the WSR-FMD relationship in healthy older adults. Sixty healthy people, comprising 28 young (27.5 ± 5.5 years) and 32 older (64.9 ± 3.7 years) individuals, underwent FMD assessment. Raw data were post-processed using custom-designed software to obtain WSR and diameter parameters. The data revealed that older people have a much altered and diminished WSR response to reactive hyperaemia compared to younger people [e.g. WSR peak: 622 (571-673) vs. 443 (396-491) 1/s in young and older respectively; P < 0.05]. However, reduced WSR alone does not appear to fully explain the reduced FMD response in older people because associations between WSR and FMD were few and weak. This was in contrast to young adults, where associations were strong. We conclude that WSR during FMD is much altered and diminished in older people, and there appears to be an 'uncoupling' of WSR from FMD in older people that may reflect a loss of precision in the reactive hyperaemia stimulus-response relationship. These findings also point to the importance and utility of comprehensively characterizing the WSR-FMD response when using reactive hyperaemia to assess vascular function.

Does obesity attenuate the beneficial cardiovascular effects of cardiorespiratory fitness?

BACKGROUND AND AIMS

Higher cardiorespiratory fitness is associated with lower pulse wave velocity and arterial stiffness in normal weight individuals, and this has not been examined in obese individuals. It is unclear whether an altered body composition acts as a modifier of the association between cardiorespiratory fitness and arterial stiffness. We examined the association between peak oxygen uptake and brachial-ankle pulse wave velocity and analysed whether body composition attenuates this association in obese middle-aged individuals.

METHODS

Bio-impedance analysis-derived body composition assessment in 212 healthy and sedentary either overweight or obese individuals was followed by measurement of brachial-ankle pulse wave velocity and spiroergometric peak oxygen uptake. Multivariate analysis was performed to analyse the association between peak oxygen uptake and brachial-ankle pulse wave velocity and to assess the moderating effect of several body composition-related interaction terms (BMI, total body mass, body fat mass, waist circumference, waist-to-height ratio) on this association.

RESULTS

Peak oxygen uptake was inversely associated with brachial-ankle pulse wave velocity (β = -0.059, 95% CI = -0.099; -0.018, p = 0.005). Testing for the impact of different body composition-related interaction terms on this association showed no significance, 95% CI lateralized towards positivity.

CONCLUSIONS

This study shows an inverse association between cardiorespiratory fitness and arterial stiffness in middle-aged obese individuals. We also found a tendency towards an attenuating impact of an obese body composition on this association. Physical fitness seems to be a stronger modulator of cardiovascular risk than body composition but the success of training efforts may be compromised by obesity.

CARRISMA: a new tool to improve risk stratification and guidance of patients in cardiovascular risk management in primary prevention

AIMS

Risk stratification is important for decisions about the intensity of treatment in primary prevention. Risk factors and lifestyle factors are responsible for over 80% of cardiovascular morbidity and mortality. However, body mass index (BMI), physical activity and smoking (cigarettes/day) are not or not quantitatively represented in the risk stratification system.

METHODS AND RESULTS

CARdiovascular RISk MAnagement (CARRISMA) is a software program considering the prognostic impact of BMI, physical activity and cigarettes per day adjusted for age and sex based on multivariate regression analyses from the literature on top of one of the three major scores to improve risk stratification. The 10-year European Society of Cardiology Systematic COronary Risk Evaluation (SCORE) cardiovascular mortality risk for an intermediate risk region, e.g. increases from 3 to 6% by considering smoking of 30 cigarettes per day instead of just 'smoking' and by taking into account a BMI of 34. Whereas the 10-year ESC cardiovascular mortality risk of a 55-year-old active individual decreases from 5 to 3%, by considering a physical activity equivalent of 2100 kcal/week, the Framingham or PROspective CArdiovascular Münster (PROCAM) risks change accordingly.

CONCLUSION

CARRISMA facilitates the application of knowledge of the current literature in the individual patient in a user-friendly manner allowing a more detailed and yet time-efficient risk stratification and risk management in primary prevention, particularly in the intermediate risk range.

Reduced flow-and acetylcholine-induced dilations in visceral compared to subcutaneous adipose arterioles in human morbid obesity

BACKGROUND AND AIMS

The hypothesis of this study was that microvascular FID and AChID is impaired in visceral (VAT) compared to SAT arterioles in morbidly obese women. An Additional aim was to determine the mechanisms contributing to FID and AChID in VAT and SAT arterioles.

METHODS AND RESULTS

Arterioles were obtained from SAT and VAT biopsies from women (BMI > 35 kg/m(2) ) undergoing bariatric surgery. Microvessels were cannulated for reactivity measurements in response to flow (pressure gradients of 10-100 cmH2 O) and to ACh (10(-9) -10(-4 ) M) with and without l-NAME, INDO, and PEG-catalase. NO and H2 O2 generation were detected in arterioles by fluorescence microscopy. FID and AChID of arterioles from VAT were reduced compared to SAT arterioles. In SAT arterioles, l-NAME, INDO, and PEG-catalase significantly reduced FID and AChID but had no effect individually on VAT arterioles' vasodilator reactivity. INDO +l-NAME reduced FID in VAT arterioles. NO-fluorescence was greater in arterioles from SAT compared to VAT arterioles. Vascular H2 O2 generation during flow was similar in both VAT and SAT.

CONCLUSION

Our results suggest that VAT arterioles display reduced vasodilator reactivity to flow and ACh compared to SAT arterioles, mediated by different regulatory mechanisms in human obesity.

Abdominal obesity is associated with arterial stiffness in middle-aged adults

BACKGROUND AND AIMS

The relation between adiposity and arterial stiffness remains controversial. We determined whether abdominal and visceral adipose tissue may be a better predictor of arterial stiffness than general obesity in middle-aged adults.

METHODS AND RESULTS

A total of 146 participants (76 men, 70 women; 50 years) were studied. The automatic vascular screening device (Omron VP-1000plus) was used to measure blood pressure simultaneously in the arms and ankles and to determine arterial stiffness by pulse wave velocity (PWV). Using multiple linear regressions, the relations between indicators of obesity and arterial stiffness were examined after adjustment for confounders. Both carotid-femoral PWV and brachial-ankle PWV were significantly associated with BMI (both P < 0.05) but not with body fat percentage. Measures of abdominal obesity, including waist circumference and visceral fat mass (via DXA), were strongly associated with PWV and remained positively associated with arterial stiffness after adjustment for age and gender. Cardiovascular fitness as assessed by maximal oxygen consumption was related to body fat percentage but not with visceral fat. More favorable cardiovascular health profile was associated with both lower visceral fat mass and PWV (both P < 0.001).

CONCLUSION

Abdominal obesity and visceral fat are associated with large artery stiffness. These findings support the importance of adiposity measures as a risk factor for arterial stiffening in middle-aged adults.

Increases in central fat mass and decreases in peripheral fat mass are associated with accelerated arterial stiffening in healthy adults: the Amsterdam Growth and Health Longitudinal Study

BACKGROUND

Central fatness is associated with higher arterial stiffness, a mechanism that may explain adiposity-related increases in cardiovascular disease risk. In contrast, peripheral fat and lean masses may counteract such adverse effects, but evidence of this contention, as derived from longitudinal studies at the general population level, is lacking.

OBJECTIVE

The objective was to investigate the associations between changes in central (ie, trunk) fat mass, peripheral (ie, limbs) fat mass, and lean masses with changes in arterial stiffness.

DESIGN

A longitudinal study in 277 (145 women) healthy adults was conducted. Body composition (dual-energy X-ray absorptiometry) and arterial stiffness estimates (ultrasound imaging) were measured repeatedly at the ages of 36 and 42 y.

RESULTS

Changes (per 10 kg) in trunk fat mass were positively associated and changes in peripheral fat mass were inversely associated with carotid Young's elastic modulus (in 10(3) ⋅ kPa) [β = 0.14 (95% CI: 0.02, 0.25) and -0.16 (-0.30, -0.01), respectively] and carotid-femoral pulse wave velocity (in m/s) [β = 1.54 (0.02, 3.07) and -1.46 (-3.48, 0.56), respectively]. Individuals in whom trunk fat increased and peripheral fat decreased over the 6-y follow-up (33% of the study population) had the steepest increases in these stiffness estimates. Notably, these changes were accompanied by minor increases in body weight, which remained within the limits of the normal range throughout.

CONCLUSIONS

Increases in trunk mass and decreases in peripheral fat mass are associated with accelerated arterial stiffening. These findings emphasize the importance of assessing regional changes in body composition, because it may enable identification of individuals with an unrecognized increased cardiovascular disease risk.

Age-related change in endothelial and microvessel function and therapeutic consequences

As the absolute numbers and proportion of older adults increases across most of the developed world, a greater understanding of the aetiopathogenic mechanisms of the increased vascular risk and their therapeutic implications becomes essential to all clinicians assessing and managing the geriatric patient. The role of endothelial function and the microcirculation is increasingly recognized in the maintenance of adequate perfusion, and their dysfunction is thought to be an early and potentially reversible mechanism by which age acts to increase cardiovascular risk.

Here we review evidence that altered microvascular function appears before other recognized predictors of vascular disease, and progresses from childhood to late adult life, preceding fulminant atherosclerotic or arteriosclerotic disease. Low birth-weight babies have reduced endothelial function in skin microvessels at 3 months, and by age ten brachial artery endothelial function is reduced in comparison with normal birth-weight babies. In overweight/obese adolescent children with clustering of traditional cardiovascular disease risk factors, endothelial function is lower compared with normal weight children and this appears to persist into early adulthood. Adult ageing is associated with impaired microvessel endothelial function and an increase in capillary blood pressure, independent of brachial artery blood pressure. Biological and lifestyle factors that influence microvessel function include body fat and visceral adiposity, sex hormone status, diet and physical activity.

Exploration of the therapeutic implications for management of endothelial dysfunction remains in embryonic state. The use of ACE-inhibitors, angiotensin receptor blockers and direct renin inhibitors in patients with evidence of microvascular damage such as retinopathy and microalbuminuria has been established; however, in the general older population the benefit has yet to be established. Therefore current recommendations are to screen for microvascular damage and if present target treatments after control of other vascular risk factors such as hypertension.

Caloric restriction with or without exercise: the fitness versus fatness debate

There is a debate over the independent effects of aerobic fitness and body fatness on mortality and disease risks.

PURPOSE

To determine whether a 25% energy deficit that produces equal change in body fatness leads to greater cardiometabolic benefits when aerobic exercise is included.

METHODS

Thirty-six overweight participants (16 males/20 females) (39 +/- 1 yr; 82 +/- 2 kg; body mass index = 27.8 +/- 0.3 kg x m2, mean +/- SEM) were randomized to one of three groups (n = 12 for each) for a 6-month intervention: control (CO, weight-maintenance diet), caloric restriction (CR, 25% reduction in energy intake), or caloric restriction plus aerobic exercise (CR + EX, 12.5% reduction in energy intake plus 12.5% increase in exercise energy expenditure). Food was provided during weeks 1-12 and 22-24. Changes in fat mass, visceral fat, VO2peak (graded treadmill test), muscular strength (isokinetic knee extension/flexion), blood lipids, blood pressure, and insulin sensitivity/secretion were compared.

RESULTS

As expected, VO2peak was significantly improved after 6 months of intervention in CR + EX only (22 +/- 5% vs 7 +/- 5% in CR and -5 +/- 3% in CO), whereas isokinetic muscular strength did not change. There was no difference in the losses of weight, fat mass, or visceral fat and changes in systolic blood pressure (BP) between the intervention groups. However, only CR + EX had a significant decrease in diastolic BP (-5 +/- 3% vs -2 +/- 2% in CR and -1 +/- 2% in CO), in low-density lipoprotein (LDL) cholesterol (-13 +/- 4% vs -6 +/- 3% in CR and 2 +/- 4% in CO), and a significant increase in insulin sensitivity (66 +/- 22% vs 40 +/- 20% in CR and 1 +/- 11% in CO).

CONCLUSIONS

Despite similar effect on fat losses, combining CR with exercise increased aerobic fitness in parallel with improved insulin sensitivity, LDL cholesterol, and diastolic BP. The results lend support for inclusion of an exercise component in weight loss programs to improve metabolic fitness.

Cardiovascular prevention in clinical practice (ESC and German guidelines 2007)

Preventive efforts should be guided by the patient's global cardiovascular (CV) risk. A risk stratification should be done in every person > age 35 with more than a single risk factor. Recommendations for improved lifestyle are applicable to all persons with CV risk factors: smoking cessation, daily exercise, normal body mass index, Mediterranean diet, blood pressure < 140 mmHg systolic, and LDL cholesterol < 130 mg/dl are beneficial. If the 10-year risk is > or = 20% for CV events or > or = 5% for CV death, additional drug interventions are usually necessary: acetylsalicylic acid 100 mg daily, statins to lower LDL cholesterol to < 100 mg/dl or, in diabetics with coronary artery disease, to < 70 mg/dl, blood pressure should be < 130 mmHg systolic, e.g., in patients with diabetes or renal disease. After bare-metal stent implantation clopidogrel should be given for > or = 4 weeks and after drug-eluting stents for > or = 6 months. In patients after myocardial infarction with an ejection fraction of < 40%, ACE inhibitors and beta-blocker should be started. Influenza vaccination improves prognosis in high-risk patients.

Human endothelial function and microvascular ageing

Age is a primary risk factor for cardiovascular disease, and this is an increasingly important public health concern because of an increase in the absolute number and proportion of the population at an older age in many countries. A key component of cardiovascular ageing is reduced function of the vascular endothelium, and this probably contributes to the impaired microvessel function observed with ageing in multiple vascular beds. In turn, impaired microvessel function is thought to contribute to the pathophysiology of cardiovascular and metabolic diseases. Here we review evidence that the first signs of altered endothelial and microvessel function can appear in childhood and at all stages of the human lifespan; low-birth-weight babies have reduced endothelial function in skin microvessels at 3 months, and by age 10 years their brachial artery endothelial function is reduced in comparison with normal-birth-weight babies. In overweight/obese adolescent children with clustering of traditional cardiovascular disease risk factors, endothelial function is reduced compared with normal-weight children, and this appears to persist into early adulthood. Adult ageing is associated with impaired microvessel endothelial function and an increase in capillary blood pressure. Biological and lifestyle factors that influence microvessel function include body fat and visceral adiposity, sex hormone status, diet and physical activity. The mechanisms underlying age-associated changes in microvessel function are uncertain but may involve alterations in nitric oxide, prostanoid, endothelium-derived hyperpolarizing factor(s) and endothelin-1 pathways.

Overweight body mass index classification modifies arterial stiffening associated with weight gain in healthy middle-aged Japanese men

The present study was conducted to clarify whether body mass index (BMI [kg/m(2)]) classifications (i.e., without excess weight, overweight, and obese) modify the rate of progression of arterial stiffening, a cardiovascular risk factor associated with weight gain. A 3-year observational study was conducted in 2,080 healthy middle-aged Japanese men (aged 42+/-10 years). Brachial-ankle pulse wave velocity (baPWV) was measured at the beginning and end of the study period. In overweight subjects (30>BMI>or=25), the estimated annual rate of increase of baPWV (ARbaPWV) in subjects with weight gain (>or=5% weight gain; ARbaPWV, 21.8+/-4.4 cm/s/year) was significantly higher than in those without weight gain (<5% weight gain; ARbaPWV, 12.5+/-1.6 cm/s/year), after adjustments for changes in blood pressure and other variables (p<0.05). This change was not observed in subjects without excess weight (BMI<25) or in obese subjects (BMI>or=30). The increase in the ARbaPWV associated with weight gain in the overweight group was also higher than that in the without excess body weight or obese groups. Our study revealed that the BMI classifications modified the annual rate of increase in arterial stiffening associated with weight gain. Weight gain seemed to accelerate arterial stiffening in overweight subjects, but not in subjects without excess weight. The weight gain in overweight subjects seemed to worsen the cardiovascular risk related to arterial stiffness in middle-aged healthy Japanese men. Thus, the prevention of weight gain should be emphasized in overweight subjects.

Large artery stiffening with weight gain in humans: role of visceral fat accumulation

We tested the hypothesis that weight gain would increase arterial stiffness in healthy nonobese adults. To address this, we overfed 14 nonobese men (age: 23+/-1 years) approximately 1000 kcal/d for 6 to 8 weeks until a 5-kg weight gain was achieved. Carotid diameters (high-resolution ultrasound) and pressures (applanation tonometry), body composition (dual energy x-ray absorptiometry), and abdominal fat distribution (computed tomography) were measured at baseline and following 4 weeks of weight stability at each individual's elevated body weight. Overfeeding increased body weight 5.1+/-0.1 kg and body fat 3.4+/-0.4 kg (both P<0.001) in 45+/-7 days. Total abdominal fat increased 46+/-7 cm(2) with weight gain due to increases in both subcutaneous (30+/-6 cm(2)) and visceral fat (15+/-4 cm(2); all P<0.01). As hypothesized, weight gain increased arterial stiffness 13+/-6% and decreased arterial compliance 21+/-4% (both P<0.05). Furthermore, those individuals above the median increase in abdominal visceral fat demonstrated a significantly greater increase in arterial stiffness (0.97+/-0.29 versus 0.06+/-0.36 U; P<0.05) compared with those below the median. Consistent with these observations, the only correlates of the changes in arterial stiffness with weight gain were the increases in total abdominal fat (r=0.794), abdominal visceral fat (r=0.651), and waist circumference (r=0.470; all P<0.05). Taken together, these findings suggest that modest weight gain is associated with increases arterial stiffness in nonobese men. The degree of large artery stiffening with weight gain seems to be determined, in part, by the amount of abdominal visceral fat gain. Importantly, this relation is independent of the amount of total body fat gained.

Cardiovascular risk, obesity, and myocardial blood flow in postmenopausal women

BACKGROUND

This study was designed to determine whether overweight or obese status is independently associated with myocardial flow reserve (MFR), an established predictor of cardiovascular mortality, in a group of postmenopausal women with no previous cardiovascular disease. Postmenopausal women are the largest group of overweight and physically inactive individuals in the United States. Increased body mass index (BMI) is consistently associated with increased cardiovascular mortality in this population. Whether this is because of obesity itself or the accompanying increase in cardiovascular risk factors (CRFs) remains controversial.

METHODS

We examined the relationship of myocardial blood flow (MBF), coronary vascular resistance, and MFR to BMI in 60 postmenopausal women with no coronary heart disease. Subjects underwent dynamic N-13 ammonia positron emission tomography for the measurement of MBF and MFR. Baseline demographics, CRF, and hemodynamic parameters were recorded for each subject. Datasets were divided into 3 groups according to BMI: normal (18 to 24), overweight (25 to 29), and obese (>or=30).

RESULTS

The overweight and obese groups showed significantly higher resting MBF and lower MFR than the normal-weight group (both P < .001), even after adjusting for CRF. A further analysis of subjects without any CRF (n = 35) showed that the MFR remained significantly lower in the obese compared with normal-weight subjects (P = .05). Levels of known markers of vascular inflammation (high-sensitivity C-reactive protein and homocysteine) and high-density lipoprotein cholesterol levels correlated with declining MFR.

CONCLUSIONS

These findings provide a mechanistic link between obesity and coronary heart disease in this population.

Relationships of cardiovascular phenotypes with healthy weight, at risk of overweight, and overweight in US youths

OBJECTIVE

This study aimed to evaluate comprehensively the cardiovascular phenotypes of cardiovascular disease-free youths at risk of overweight, in comparison with healthy weight and overweight.

METHODS

Casual and ambulatory blood pressure measurements, noninvasive hemodynamic profiles, pulse wave velocity, left ventricular structure and function, and overnight sodium excretion were examined in a cohort of US black and white youths (n = 972; mean age: 17.6 +/- 3.3 years).

RESULTS

The occurrence of at risk of overweight was approximately 17% in either black youths or white youths. In white youths, there was a approximately 2-mmHg increase in casual systolic blood pressure for each increasing step in the 3 BMI categories (healthy weight, 109.5 +/- 0.5 mmHg; at risk of overweight, 111.5 +/- 0.6 mmHg; overweight, 113.5 +/- 1.1 mmHg). Ambulatory systolic blood pressure showed a similar increase with the increase in BMI. A blunted nocturnal decline in ambulatory diastolic blood pressure with the categorical BMI increase was observed in black youths. In both racial groups, cardiac output and stroke volume were significantly enhanced sequentially from healthy weight to at risk of overweight to overweight. In black youths, both casual and ambulatory heart rate increased significantly with the increase in BMI. Moreover, there was a linear increase of left ventricular mass index from the healthy-weight group to the at risk of overweight group, with the overweight group having the highest value. In white youths, carotid-dorsalis pedis pulse wave velocity increased significantly as the BMI increased. Regardless of race, overnight sodium excretion showed a significant increase from healthy-weight subjects to overweight subjects, with at risk of overweight subjects having intermediate values.

CONCLUSIONS

Youths at risk of overweight, compared with healthy-weight youths, seem to have increased cardiovascular risks. Our data suggest that the status of at risk of overweight already has clinical implications in youths.

Are we misunderstanding beta-blockers

In myocardial ischaemia and heart failure, beta-blockers with intrinsic sympathomimetic activity (ISA) e.g. pindolol, xamoterol, bucindolol, nebivolol, have performed poorly in reducing morbidity and mortality. In both indications beta-1 blockade is the vital active ingredient. Beta-1 blockade (bisoprolol) is now an alternative first-line choice to Ace-inhibition in the treatment of heart failure. The therapeutic role of beta-blockers in hypertension is less well understood, particularly since the new recommendations in the UK from the NICE committee stating that: 1. beta-blockers are no longer preferred as a routine initial therapy, 2. the combination with diuretics is discouraged due to the risk of induced diabetes, and 3. in younger patients first-choice initial therapy should be an ACE-inhibitor. Recent data from the Framingham Heart Study and other epidemiological studies have indicated that the development of diastolic hypertension in younger subjects is closely linked to weight-increase and an increase in peripheral resistance; such subjects have a high adrenergic drive and cardiac output. In contrast, elderly systolic hypertension mostly arises de novo via poor vascular compliance. Thus in younger, probably overweight, hypertensives (including diabetics) first-line beta-blockade has performed well in preventing myocardial infarction (a fact hidden by meta-analyses that do not take age into account). Conversely, in elderly hypertensives first-line beta-blockade (atenolol) has performed poorly in reducing cardiovascular risk (due to partial beta-2 blockade atenolol evokes metabolic disturbance and does not improve vascular compliance, or effectively lower central aortic pressure or reverse left ventricular hypertrophy). Thus beta-blockers like atenolol are ill-equipped for first-line therapy in elderly hypertension. Some beta-blockers, e.g. bisoprolol (up to 10 mg/day is highly beta-1 selective) and nebivolol (beta-2/3 intrinsic sympathomimetic activity), do improve vascular compliance and cause no metabolic disturbance. Beta-blockers as second-line to low-dose diuretics (which, by improving vascular compliance and increasing sympathetic nerve activity, create an optimal environment for beta-blockade) in elderly hypertension (including diabetics) have performed well in reducing cardiovascular events (this combination has the added bonus of reducing the risk of bone fracture by about 30%). Meta-analyses which include studies where it is unclear whether a diuretic or beta-blocker was a first-line therapy will dilute the benefit stemming from first-line diuretic/second-line beta-blockade. Hypertensives (of all ages) with ischaemia are well suited to beta-blockade.

Fatness is a better predictor of cardiovascular disease risk factor profile than aerobic fitness in healthy men

BACKGROUND

The prevalence of cardiovascular disease (CVD) is partly attributable to an inactive and/or overweight population. However, the independent association of body fatness and aerobic fitness with CVD risk factors is uncertain. We sought to determine whether fatness or fitness better predicted traditional CVD risk factors in men with broad fatness, aerobic fitness, and age ranges using 3 expressions of adiposity.

METHODS AND RESULTS

In 135 carefully screened healthy men, we measured 18 established CVD risk factors, body mass index, total percent body fat, waist circumference, and maximal aerobic capacity. Body mass index, percent body fat, and waist circumference were consistently associated with all metabolic risk factors (r=-0.44 to 0.51, P<0.05) after partialling out the effects of aerobic fitness and age. Body mass index and waist circumference were also independently associated with selective hemodynamic risk factors (r=0.20 to 0.30, P< or =0.01). In contrast, aerobic fitness was independently associated with only selective metabolic risk factors (r=-0.21 to 0.19, P<0.05) and was not associated with any hemodynamic risk factors (P>0.05). Both aerobic fitness and body fatness were independently associated with selective hemostatic risk factors (r=-0.22 to -0.26, P< or =0.01; r=-0.32 to 0.48, P<0.05, respectively). Overall, fatness was more strongly and consistently associated with CVD risk factors than aerobic fitness.

CONCLUSIONS

Body fatness is a better predictor of CVD risk factor profile than aerobic fitness in healthy men. Although habitual physical activity is an effective strategy for preventing CVD, elevated body fatness is associated with an adverse CVD risk factor profile independently of aerobic fitness.

Aortic Input Impedance Increases With Age in Healthy Men and Women

Aortic input impedance represents the hydraulic load presented by the systemic circulation to the left ventricle of the heart and is increased in patients with cardiovascular disease. Aging is a strong independent risk factor for cardiovascular disease and could exert this effect partly through an increase in modulus of aortic input impedance. We used a novel noninvasive technique to determine aortic input impedance in 71 healthy men and women aged 20 to 69 years. We found that the aortic input impedance spectrum was shifted rightward with advancing age, characterized by a 37% increase in the frequency of the minimum modulus between the third and seventh decade (P<0.0001). The frequency of the minimum modulus correlated with age in all subjects (r=0.48; P<0.0001), in men (r=0.43; P<0.005), and in women (r=0.53; P=0.001). Although several physical characteristics were associated with the frequency of the minimum modulus (bivariate correlation), a regression model that included age and these physical characteristics showed that age was the only independent predictor of the frequency of the minimum modulus. We conclude that aortic input impedance increases with advancing age in healthy men and women. This increase in aortic input impedance may be an important mechanism by which age increases the risk of cardiovascular disease in humans.