Obesity and the elderly

The prevalence of obesity is rising progressively, even among older age groups. By the year 2030 to 2035 over 20% of the adult US population and over 25% of the Europeans will be aged 65 years or older. The predicted prevalence of obesity in Americans, 60 years and older was 37% in 2010. The predicted prevalence of obesity in Europe in 2015 varies between 20% and 30% dependent on the model used. This means 20.9 million obese 60 years or older people in the United States in 2010 and 32 million obese elders in 2015 in EU. Although cutoff values of body mass index, waist circumference, and percentages of fat mass have not been defined for the elderly, it is clear from several meta-analyses that mortality and morbidity associated with overweight and obesity only increases at a body mass index >30 kg/m(2). Thus, treatment should only be offered to patients who are obese rather than overweight and who have functional impairments, metabolic complications, or obesity-related diseases, that can benefit from weight loss. The weight loss therapy should minimize muscle and bone loss and vigilance as regards the development of sarcopenic obesity--a combination of an unhealthy excess of body fat with a detrimental loss of muscle and fat-free mass including bone--is important. Lifestyle intervention should be the first step and consists of a diet with a 500 kcal energy deficit and an adequate intake of protein of high biological quality, together with calcium and vitamin D, behavioral therapy, and multicomponent exercise. Multicomponent exercise includes flexibility training, balance training, aerobic exercise, and resistance training. The adherence rate in most studies is around 75%. Knowledge of constraints and modulators of physical inactivity should be of help to engage the elderly in physical activity. The role of pharmacotherapy and bariatric surgery in the elderly is largely unknown as in most studies people aged 65 years and older were excluded.     

Does physical activity reduce the risk of cardiovascular disease in overweight and obese individuals?

For individuals considered overweight or obese, physical activity or more structured exercise is recommended to facilitate weight loss and reduce risk of long-term disease. Physical activity and structured exercise programs, however, rarely result in significant loss of body weight or body fat, especially in women. Despite the minimal effect of exercise on weight loss, exercise has multiple health benefits for overweight and obese individuals, including skeletal muscle adaptations that improve fat and glucose metabolism and insulin action; enhanced endothelial function; favorable changes in blood lipids, lipoproteins, and hemostatic factors; and reductions in blood pressures, postprandial lipemia, and proinflammatory markers. These exercise-induced adaptations occur independently of changes in body weight or body fat. Thus, physically inactive individuals considered at increased risk for cardiovascular disease due to both sedentary lifestyle and a high body mass index should be encouraged to engage in regular physical activity, regardless of whether a more active lifestyle leads to weight loss.     

Exercise, insulin resistance, and hypertension: a complex relationship

More than 300,000 deaths occur annually in the United States alone as a result of obesity, poor dietary habits, or physical inactivity. Obesity is now an increasingly recognized independent risk factor for cardiovascular disease and leads to numerous other comorbidities. The causal relationships between obesity and both insulin resistance and hypertension have been consistently demonstrated in numerous studies. The relationships consist of cascading events involving insulin, leptin, adiponectin, and other hormones that often precipitate the development of metabolic syndrome. As we learn more about the metabolic activity of the adipose tissue, we can better identify the mechanisms that associate weight reduction with a decrease in health risks. Evidence suggests that exercise produces a positive effect on weight reduction, insulin sensitivity, and blood pressure. Therefore, weight reduction and therapeutic changes in lifestyle should be encouraged in all overweight and obese patients. It is imperative to increase the awareness of the obesity epidemic and to emphasize the importance of exercise as both treatment and prevention of metabolic disease.     

The DASH Diet and Insulin Sensitivity

Lifestyle modifications, including adoption of the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, weight loss in individuals who are overweight or obese, and physical activity, are effective in the prevention and treatment of hypertension. A healthy lifestyle may also have beneficial effects on metabolic abnormalities, such as insulin resistance, that are associated with high blood pressure. This review examines the independent and combined effects of the DASH diet and weight loss plus exercise on blood pressure and insulin sensitivity, with a focus on recently published results from the ENCORE study. Our data suggest that the DASH eating plan alone lowers blood pressure in overweight individuals with higher than optimal blood pressure, but significant improvements in insulin sensitivity are observed only when the DASH diet is implemented as part of a more comprehensive lifestyle modification program that includes exercise and weight loss.     

Genetic effects in the response of adipose tissue lipoprotein lipase activity to prolonged exercise. A twin study

Our laboratory has reported large inter-individual differences in the metabolic response of adipose tissue to prolonged exercise in humans. The present study investigated the contribution of heredity in the metabolic changes of adipose tissue to prolonged exercise in 11 monozygotic and 10 dizygotic pairs of male twins, 18 to 27 years of age, studied immediately before and after a 90 min bout of exercise. The sum of 7 skinfold thicknesses and percent of fat from underwater weighing were used as body fat indicators (BFI). Subcutaneous adipose tissue was excised and fat cell weight (FCW) determined. The activity of adipose tissue lipoprotein lipase (LPL) released with heparin was also measured. BFI and FCW were identical in both types of twins. As previously reported, LPL activity was increased by exercise (P less than 0.01) in both type of twins. The changes observed for LPL activity were more similar in monozygotic twins than in dizygotic twins resulting in a significant level of inheritance (P less than 0.05). A genetic component for LPL activity supports the hypothesis that adipose tissue LPL could be genetically determined not only in its basal activity but also in response to stresses such as exercise.     

Exercise for prevention and treatment of cardiovascular disease,type 2 diabetes,and metabolic syndrome

A considerable number of observational and intervention studies support the role of exercise as a cornerstone in prevention and treatment of cardiovascular disease (CVD), type 2 diabetes (T2D), and the metabolic syndrome. Physical activity and cardiorespiratory fitness are also associated with reduced mortality rates among persons with CVD, T2D, and metabolic syndrome. Exercise has definite acute effects on a number of risk markers for CVD and T2D, in addition to more substantial benefits with chronic training. Both aerobic and resistance exercise have therapeutic value, largely independent of weight loss, and should be included in exercise programs.     

Physical activity and obesity.

The regular practice of physical activity promotes metabolic adaptations that facilitate the regulation of energy and fat balance. These effects are important for a better control of body weight in the obese individual and should enable him or her to involve adipose tissue to a lesser extent in this regulation. Physical activity favours a negative energy and fat balance, particularly if activities are prolonged and vigorous. The achievement of a negative energy and fat balance with physical activity also strongly depends on the nutritional context in which it is performed. In the long term, an active lifestyle and low-fat food habits are expected to induce a substantial body weight loss in the obese. This weight loss is progressively attenuated over time, presumably because of the decreased impact of a reduced adipose tissue mass on the regulation of energy and fat balance. For the obese individual complying with an activity programme and healthy food habits, a body weight loss of 10% is a realistic goal before the occurrence of resistance to further loss of body fat.     

Exercise and obesity

The prevalence of obesity has increased dramatically during the past decade in the USA. This is despite an estimated 50 million Americans who try to lose weight each year. The increasing prevalence of obesity is particularly alarming due to the numerous health implications associated with this condition, including coronary artery disease, hypertension, diabetes, hyperlipidemia, cancer, and various musculoskeletal conditions. The economic impact of treating illnesses associated with obesity has been estimated to be US$40 billion in the USA. Dieting is largely ineffective in maintaining initial weight loss as numerous studies suggest the majority of dieters regain all lost weight with 3-5 years. On, the other hand, regular exercise has been shown to be one of the best predictors of successful weight maintenance. Moreover, studies indicate that improved fitness through regular physical activity reduces cardiovascular morbidity and mortality for overweight individuals even if they remain overweight. Providing advice about exercise to overweight or obese individuals requires explicit information about the frequency, intensity, duration, and type of physical activity that should be performed. The ultimate goal for the exercising obese patient is to make a life-long commitment to achieving reasonable energy expenditure through routine physical activity.     

Cardiorespiratory fitness and body mass index as predictors of cardiovascular disease mortality among men with diabetes

BACKGROUND: Questions remain as to whether higher levels of cardiorespiratory fitness, a measure of regular physical activity, are associated with lower risk of cardiovascular disease (CVD) mortality in overweight and obese individuals with diabetes. Our objective was to quantify the independent and joint relations of cardiorespiratory fitness (hereafter, fitness) and body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters) with CVD mortality in men with diabetes. METHODS: This study was conducted using prospective observational data from the Aerobics Center Longitudinal Study. Study participants comprised 2316 men with no history of stroke or myocardial infarction and who were diagnosed as having diabetes (mean [SD] age, 50 [10] years); had a medical examination, including a maximal exercise test during 1970 to 1997 with mortality surveillance to December 31, 1998; and had a BMI of 18.5 or greater and less than 35.0. The main outcome measure was CVD mortality across levels of fitness with stratification by BMI. RESULTS: We identified 179 CVD deaths during a mean (SD) follow-up of 15.9 (7.9) years and 36,710 man-years of exposure. In a model containing age, examination year, fasting glucose level, systolic blood pressure, parental history of premature CVD, total cholesterol level, cigarette smoking, abnormal resting, and exercise electrocardiograms, a significantly higher adjusted risk of mortality was observed in men with a low fitness level who were normal weight (hazard ratio, 2.7 [95% confidence interval, 1.3-5.7]), overweight (hazard ratio, 2.7 [95% confidence interval, 1.4-5.1]), and class 1 obese (hazard ratio, 2.8 [95% confidence interval, 1.4-5.1]) compared with normal weight men with a high fitness level. CONCLUSION: In this cohort of men with diabetes, low fitness level was associated with increased risk of CVD mortality within normal weight, overweight, and class 1 obese weight categories.     

Leptin increases skeletal muscle lipoprotein lipase and postprandial lipid metabolism in mice

The ability of leptin to preserve lean tissue during weight loss may be in part due to differences in nutrient partitioning. Because lipoprotein lipase (LPL) plays a key role in partitioning lipid nutrients, this study was conducted to test the hypothesis that leptin would modify the tissue-specific regulation of LPL and result in increased lipid oxidation and decreased storage. The effects of daily intraperitoneal leptin injections (2 mg/kg body weight) over 2 weeks on LPL activity and postprandial lipid metabolism were tested in both wild-type (WT), leptin-deficient ob/ob obese mice and mice pair fed to the leptin-treated mice. On the experimental day, mice were given food by gavage, blood was drawn periodically, and adipose tissue and skeletal muscle were harvested for measurements of LPL activity at 240 minutes. After 2 weeks of leptin administration, skeletal muscle LPL (SMLPL) activity was increased in leptin-treated compared with pair-fed (P = .012) and WT (P = .002) mice. There was no effect of leptin or pair feeding on postprandial adipose tissue LPL activity. In ob/ob mice, leptin treatment normalized the decrease in postprandial free fatty acid concentration (P = .066). Leptin had no effect on either the area under the triglyceride (TG) excursion or the integrated area under the TG excursion in WT mice. In ob/ob mice, however, the TG excursion was lower in the leptin-treated than the pair-fed mice by area under the TG excursion (P = .012) and was lower than in the WT mice by integrated area under the TG excursion (P = .027). As expected, 2 weeks of leptin treatment decreased body weight in both the WT and ob/ob mice (−2.6% and −10.4%, respectively). Leptin treatment increased SMLPL, an effect that may have contributed to the leptin-induced weight loss. The leptin-induced decreased postprandial TG excursion in ob/ob mice suggests that leptin acts to augment clearance of postprandial TG-rich lipoprotein lipid and that this increase may in part be secondary to the increased activity of SMLPL. The trend for decreased postprandial free fatty acid may indicate that leptin decreases adipose tissue lipid stores without increasing lipolysis.     

Exercise in the treatment of obesity.

Exercise is an important component of behavioral weight control interventions, and exercise may be most effective for weight control when combined with modifications to energy intake. Clinicians should initially encourage overweight and obese adults to adopt at least 150 minutes of moderate-intensity exercise per week (30 min x 5 d/wk), because this level of exercise has been shown to improve health-related outcomes. Higher levels of exercise, however, may be necessary to enhance long-term weight loss and to facilitate weight loss maintenance. It is now recommended that exercise be progressively increased to approximately 300 minutes per week (60 min x 5 d/wk) to optimize the impact of exercise on body weight regulation. Adoption of this high level of exercise may be challenging, however, and therefore clinicians should counsel patients to incorporate intermittent and lifestyle approaches for exercise to maximize adherence. Moreover, devices such as pedometers may facilitate goal-setting and self-monitoring of exercise, and these are critical components of effective behavioral interventions. Incorporation of these recommendations may increase the likelihood of clinicians' prescribing exercise for overweight and obese adults to effectively manage their body weight.     

Decrease in visceral fat following diet-induced weight loss in upper body compared to lower body obese premenopausal women

BACKGROUND: Obesity is associated with numerous metabolic disturbances, such as insulin resistance, diabetes mellitus type 2, dyslipidemia, and hypertension. An excess of fat within the abdomen, so-called visceral adiposity, confers a greater and independent health risk of metabolic and cardiovascular complications than does adipose tissue accumulation elsewhere. The present study aimed to investigate a possible differential effect of diet-induced weight loss in visceral fat mass and metabolic parameters in obese individuals with the upper body (UBO) and lower body (LBO) obese phenotype. METHODS: The obese subjects were prescribed a liquid, very-low calorie diet to reduce 50% of their overweight (15% body weight loss). Specific body fat measurements (MRI, BIA), anthropometrics, and fasting metabolic parameters were obtained in control subjects and two groups of obese subjects (UBO and LBO) before and after weight loss. RESULTS: Weight loss was accompanied by significant decreases in total, subcutaneous, and visceral fat in both UBO and LBO women. The largest reduction in visceral fat mass was found in the UBO women (absolute decrease 223+/-32 cm(2) vs 122+/-91 cm(2) in LBO women; P=0.01), while the amount of visceral fat was reduced to normal levels in LBO women (155+/-25 cm(2) after weight loss vs 143+/-17 cm(2) in controls; P=NS). Furthermore, weight loss significantly lowered fasting glucose, total cholesterol, and LDL cholesterol concentrations in UBO women. CONCLUSION: The obese phenotype is preserved after body weight loss. UBO women have to lose a larger amount of overweight in order to bring the amount of fat in the visceral depot down to normal levels and to obtain normalization of their cardiovascular risk profile.     

Körperliches Training in der Behandlung von KHK und Adipositas

Endothelial dysfunction has been identified as a major predictor of future cardiovascular events and precedes the development of coronary artery disease (CAD). Regular physical exercise training--as part of a multifactorial intervention--corrects endothelial dysfunction, improves symptoms in patients with CAD, augments myocardial perfusion, and reduces mortality of these patients. This review discusses potential mechanisms, which might be responsible for the exercise training-mediated reduction of mortality in secondary prevention. The activation of stem cells, which are known to regenerate damaged endothelium and promote the development of new vessels by vasculogenesis, the regression of atherosclerosis, the formation of collaterals, and the partial correction of endothelial dysfunction as a consequence of molecular adaptations will be evaluated in this context. However, the positive effects of exercise training in primary and secondary prevention of cardiovascular diseases are not restricted to the correction of endothelial dysfunction. Regular physical activity, either alone or as part of a multifactorial intervention consisting of diet and exercise training, is known to promote effective weight loss. Especially in patients with metabolic syndrome, weight reduction beneficially effects blood glucose control. It increases the levels of vasculoprotective high-density lipoprotein and augments the physical exercise capacity of these individuals. Additionally, regular physical activity attenuates the diet-induced loss in fat-free body mass by 50%, improves body composition and counteracts the reduction in basal energy expenditure, which is another big advantage compared to diet alone in the treatment of obesity. Moreover, physical exercise training is essential to maintain a body weight that has been achieved by caloric restriction. It is important to look for exercise interventions that can easily be integrated in daily life and are not associated with an increased risk of trauma, even in severely obese individuals. Most importantly, patients should enjoy the proposed kind of physical exercise.     

Obesity and cardiovascular disease: pathophysiology, evaluation, and effect of weight loss: an update of the 1997 American Heart Association Scientific Statement on Obesity and Heart Disease from the Obesity Committee of the Council on Nutrition, Physical Activity, and Metabolism

Obesity is becoming a global epidemic in both children and adults. It is associated with numerous comorbidities such as cardiovascular diseases (CVD), type 2 diabetes, hypertension, certain cancers, and sleep apnea/sleep-disordered breathing. In fact, obesity is an independent risk factor for CVD, and CVD risks have also been documented in obese children. Obesity is associated with an increased risk of morbidity and mortality as well as reduced life expectancy. Health service use and medical costs associated with obesity and related diseases have risen dramatically and are expected to continue to rise. Besides an altered metabolic profile, a variety of adaptations/alterations in cardiac structure and function occur in the individual as adipose tissue accumulates in excess amounts, even in the absence of comorbidities. Hence, obesity may affect the heart through its influence on known risk factors such as dyslipidemia, hypertension, glucose intolerance, inflammatory markers, obstructive sleep apnea/hypoventilation, and the prothrombotic state, in addition to as-yet-unrecognized mechanisms. On the whole, overweight and obesity predispose to or are associated with numerous cardiac complications such as coronary heart disease, heart failure, and sudden death because of their impact on the cardiovascular system. The pathophysiology of these entities that are linked to obesity will be discussed. However, the cardiovascular clinical evaluation of obese patients may be limited because of the morphology of the individual. In this statement, we review the available evidence of the impact of obesity on CVD with emphasis on the evaluation of cardiac structure and function in obese patients and the effect of weight loss on the cardiovascular system.     

Is serum leptin related to physical function and is it modifiable through weight loss and exercise in older adults with knee osteoarthritis?

OBJECTIVE: To determine the effect of weight loss and exercise interventions on serum leptin and to investigate the relationship of physical function and osteoarthritis (OA) severity with serum leptin in older overweight and obese adults with knee OA. In addition, the study examined if serum leptin predicts weight loss. DESIGN: Longitudinal, controlled clinical trial of weight loss and exercise interventions. SUBJECTS: Community dwelling, older, overweight and obese adults (n=316; >60 years of age; body mass index >/=28.0 kg m(-2)) with symptomatic knee OA and self-reported difficulty in performing selected physical activities were recruited. INTERVENTIONS: Participants were randomized into one of four groups for the 18-month study duration: Healthy Lifestyle Controls, Dietary Weight Loss (Diet), Exercise Training (Exercise), and a combination of Dietary Weight Loss and Exercise Training (Diet+Exercise). The weight loss goal for the two Diet groups was 5% from baseline at 18 months. Participants in the Exercise groups were trained for 3 days week(-1), 60 min day(-1). MEASUREMENTS: Body weight, body mass index, serum leptin, physical function, and OA severity were measured at baseline, 6 months, and 18 months. RESULTS: Diet and Diet+Exercise groups lost 5.3 and 6.1% of their weight, respectively, at 18 months with the Exercise group losing 2.9%. There was a significant main effect of weight loss on serum leptin with a decrease in serum leptin averaged across the 6- and 18-month time points for the Diet and Diet+Exercise groups compared to the other two groups (beta=0.245; P<0.01). No main effect for exercise training was observed. Serum leptin was related to self-reported physical function. In all participants, a mixed model analysis demonstrated that lower levels of baseline serum leptin predict larger weight loss (beta=-2.779; P=0.048). CONCLUSION: Decreases in serum leptin may be one mechanism by which weight loss improves physical function and symptoms in OA patients.     

Randomized trial of exercise effect on intrahepatic triglyceride content and lipid kinetics in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) and alterations in hepatic lipoprotein kinetics are common metabolic complications associated with obesity. Lifestyle modification involving diet-induced weight loss and regular exercise decreases intrahepatic triglyceride (IHTG) content and very low density lipoprotein (VLDL) triglyceride (TG) secretion rate. The aim of this study was to evaluate the weight loss-independent effect of following the physical activity guidelines recommended by the Department of Health and Human Services on IHTG content and VLDL kinetics in obese persons with NAFLD. Eighteen obese people (body mass index [BMI]: 38.1 ± 4.6 kg/m(2)) with NAFLD were randomized to 16 weeks of exercise training (45%-55% VO(2peak) , 30-60 minutes × 5 days/week; n = 12) or observation (control; n = 6). Magnetic resonance spectroscopy and stable isotope tracer infusions in conjunction with compartmental modeling were used to evaluate IHTG content and hepatic VLDL-TG and apolipoprotein B-100 (apoB-100) secretion rates. Exercise training resulted in a 10.3% ± 4.6% decrease in IHTG content (P < 0.05), but did not change total body weight (103.1 ± 4.2 kg before and 102.9 ± 4.2 kg after training) or percent body fat (38.9% ± 2.1% before and 39.2% ± 2.1% after training). Exercise training did not change the hepatic VLDL-TG secretion rate (17.7 ± 3.9 μmol/min before and 16.8 ± 5.4 μmol/min after training) or VLDL-apoB-100 secretion rate (1.5 ± 0.5 nmol/min before and 1.6 ± 0.6 nmol/min after training). CONCLUSION: Following the Department of Health and Human Services recommended physical activity guidelines has small but beneficial effects on IHTG content, but does not improve hepatic lipoprotein kinetics in obese persons with NAFLD.     

Obesity, regional body fat distribution, and the metabolic syndrome in older men and women

BACKGROUND: The metabolic syndrome is a disorder that includes dyslipidemia, insulin resistance, and hypertension and is associated with an increased risk of diabetes and cardiovascular disease. We determined whether patterns of regional fat deposition are associated with metabolic syndrome in older adults. METHODS: A cross-sectional study was performed that included a random, population-based, volunteer sample of Medicare-eligible adults within the general communities of Pittsburgh, Pa, and Memphis, Tenn. The subjects consisted of 3035 men and women aged 70 to 79 years, of whom 41.7% were black. Metabolic syndrome was defined by Adult Treatment Panel III criteria, including serum triglyceride level, high-density lipoprotein cholesterol level, glucose level, blood pressure, and waist circumference. Visceral, subcutaneous abdominal, intermuscular, and subcutaneous thigh adipose tissue was measured by computed tomography. RESULTS: Visceral adipose tissue was associated with the metabolic syndrome in men who were of normal weight (odds ratio, 95% confidence interval: 2.1, 1.6-2.9), overweight (1.8, 1.5-2.1), and obese (1.2, 1.0-1.5), and in women who were of normal weight (3.3, 2.4-4.6), overweight (2.4, 2.0-3.0), and obese (1.7, 1.4-2.1), adjusting for race. Subcutaneous abdominal adipose tissue was associated with the metabolic syndrome only in normal-weight men (1.3, 1.1-1.7). Intermuscular adipose tissue was associated with the metabolic syndrome in normal-weight (2.3, 1.6-3.5) and overweight (1.2, 1.1-1.4) men. In contrast, subcutaneous thigh adipose tissue was inversely associated with the metabolic syndrome in obese men (0.9, 0.8-1.0) and women (0.9, 0.9-1.0). CONCLUSION: In addition to general obesity, the distribution of body fat is independently associated with the metabolic syndrome in older men and women, particularly among those of normal body weight.