Obesity paradox does exist

Association of obesity and long-term mortality in patients with acute myocardial infarction with and without diabetes mellitus: results from the MONICA/KORA myocardial infarction registry

Background

Paradoxically, beneficial effects of overweight and obesity on survival have been found in patients after cardiovascular events such as acute myocardial infarction (AMI). This obesity paradox has not been analyzed in AMI patients with diabetes even though their cardiovascular morbidity and mortality is increased compared to their counterparts without diabetes. Therefore, the objective of this long-term study was to analyze the association between body mass index (BMI) and all-cause mortality in AMI patients with and without diabetes mellitus.

Methods

Included in the study were 1190 patients with and 2864 patients without diabetes, aged 28-74 years, recruited from a German population-based AMI registry. Patients were consecutively hospitalized between 1 January 2000 and 31 December 2008 with a first ever AMI and followed up until December 2011. Data collection comprised standardized interviews and chart reviews. To assess the association between BMI and long-term mortality from all causes, Cox proportional hazards models were calculated adjusted for risk factors, co-morbidities, clinical characteristics, in-hospital complications as well as medical and drug treatment.

Results

AMI patients of normal weight (BMI 18.5-24.9 kg/m²) had the highest long-term mortality rate both in patients with and without diabetes with 50 deaths per 1000 person years and 26 deaths per 1000 person years, respectively. After adjusting for a selection of covariates, a significant, protective effect of overweight and obesity on all-cause mortality was found in AMI patients without diabetes (overweight: hazard ratio (HR) 0.73, 95% confidence interval (CI) 0.58-0.93; p=0.009; obesity: HR 0.64, 95% CI 0.47-0.87; p=0.004). In contrast, an obesity paradox was not found in AMI patients with diabetes. However, stratified analyses showed survival benefits in overweight AMI patients with diabetes who had been prescribed statins prior to AMI (HR 0.51, 95% CI 0.29-0.89, p=0.018) or four evidence-based medications at hospital-discharge (HR 0.52, 95% CI 0.34-0.80, p=0.003).

Conclusion

In contrast to AMI patients without diabetes, AMI patients with diabetes do not experience a survival benefit from an elevated BMI. To investigate the underlying reasons for these findings, further studies stratifying their samples by diabetes status are needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0189-0) contains supplementary material, which is available to authorized users.

Counterintuitive relationship between visceral fat and all-cause mortality in an elderly Asian population

OBJECTIVE

Abdominal obesity is considered to be a risk factor for mortality. However, recent studies indicate that overweight may be negatively associated with mortality ("obesity paradox"). The relationships between mortality and various obesity markers in an elderly Asian cohort were evaluated.

METHODS

Subjects of the Korean Longitudinal Study on Health and Aging (KLoSHA) (n = 1000, age ≥65 years) were included. The visceral fat area (VFA) and subcutaneous fat area (SFA) were measured using computed tomography.

RESULTS

A total of 222 deaths occurred during the 6-year follow-up (median = 5.2 [range 0.1-6.3] years). Body mass index (BMI), VFA, SFA, and total fat mass were negatively associated with all-cause mortality in the univariable analyses (hazard ratio [HR] 0.67 per 1 SD [95% CI 0.57-0.77], 0.66 [0.55-0.79], 0.73 [0.61-0.86], and 0.74 [0.63-0.87], respectively). BMI and VFA were significantly associated with all-cause mortality in the multivariable analyses (HR 0.85 per 1 SD [95% CI 0.73-0.99] and 0.64 [0.47-0.87], respectively). When stratified by quartiles, the HR associated with VFA was the lowest in the third quartile.

CONCLUSIONS

In this observational study with a short follow-up of elderly Asian people, higher amounts of visceral fat, a marker for central obesity, were associated with decreased all-cause mortality.

A discursive look at large bodies--implications for discursive approaches in nursing and health research

This article illuminates discursive constructions of large bodies in contemporary society and discusses what discursive approaches might add to health care. Today, the World Health Organization describes a current "epidemic of obesity" and classifies large bodies as a medical condition. Texts on the obesity epidemic often draw upon alarming perspectives that involve associations of threat and catastrophe. The concern we see for body size in contemporary discourse is not new. Understandings of body size in Western societies are highly cultural and normative and could be different. The way we approach large bodies affects health care practice as well as subjects' self-perceptions.

Modern obesity pharmacotherapy: weighing cardiovascular risk and benefit

Obesity is a major correlate of cardiovascular disease. Weight loss improves cardiovascular risk factors and has the potential to improve outcomes. Two drugs, phentermine plus topiramate and lorcaserin, have recently been approved by the US Food and Drug Administration for the indication of obesity; a third, bupropion plus naltrexone, is under consideration for approval. In clinical trials, these drugs cause weight loss and improve glucose tolerance, lipid profile, and, with the exception of bupropion plus naltrexone, blood pressure. However, their effect on cardiovascular outcomes is unknown. In defining appropriate roles for these drugs in preventive cardiology, it is important to remember the checkered history of drugs for obesity. New weight-loss drugs share the serotonergic and sympathomimetic mechanisms that proved harmful in the cases of Fen-Phen and sibutramine, respectively, albeit with significant differences. Given these risks, randomized cardiovascular outcomes trials are needed to establish the safety, and potential benefit, of these drugs. This review will discuss the history of pharmacotherapy for obesity, existing efficacy and safety data for the novel weight-loss drugs, and issues in the design of postapproval clinical trials.

Epicardial adipose tissue volume as a marker of coronary artery disease severity in patients with diabetes independent of coronary artery calcium: findings from the CTRAD study

AIMS

The association between epicardial adipose tissue (EAT) volume and coronary artery disease (CAD) severity was evaluated, independent of traditional risk factors and coronary artery calcium (CAC) scores, in patients with diabetes type 2 (DM-2) using cardiac computed tomography angiography (CTA).

METHODS

A multivariate analysis was utilized to assess for an independent association after calculating EAT volume, CAD severity, and calcium scores in 92 patients with DM-II from the CTRAD study. We graded CAD severity as none (normal coronaries), mild-moderate (<70% stenosis), and severe (70% or greater stenosis).

RESULTS

A total of 39 (42.3%) asymptomatic patients with diabetes did not have CAD; 30.4% had mild/moderate CAD; and 27.1% had severe CAD. Mean EAT volume was highest in patients with severe CAD (143.14 cm(3)) as compared to mild/moderate CAD (112.7 cm(3)), and no CAD (107.5 cm(3)) (p = 0.003). After adjustment of clinical risk factors, notably, CAC score, multivariate regression analysis showed EAT volume was an independent predictor of CAD severity in this sample (odds ratio 11.2, 95% confidence interval 1.7-73.8, p = 0.01).

CONCLUSIONS

Increasing EAT volume in asymptomatic patients with DM-II is associated with presence of severe CAD, independent of BMI and CAC, as well as traditional risk factors.

Weight loss and physical activity for disease prevention in obese older adults: an important role for lifestyle management

Weight loss in older adults has been a controversial topic for more than a decade. An obesity paradox has been previously described and the issue of weight status on health outcomes remains a highly debated topic. However, there is little doubt that physical activity (PA) has a myriad of benefits in older adults, especially in obese individuals who are inactive and have a poor cardiometabolic profile. In this review, we offer a critical view to clarify misunderstandings regarding the obesity paradox, particularly as it relates to obese older adults. We also review the evidence on PA and lifestyle interventions for the improvement of cardiorespiratory fitness, which can prevent disease and provide benefits to obese older adults, independent of weight changes.

The anesthetic approach to operative delivery of the extremely obese parturient

Extreme obesity (BMI ≥ 40) is thought to complicate approximately 5% of deliveries in the United States. Extreme obesity puts a pregnant woman at an increased risk for cardiovascular disease, including hypertension, coronary artery disease, and congestive heart failure; respiratory disease, including obstructive sleep apnea and asthma; as well as pregnancy-specific diseases including pregnancy-induced hypertension and gestational diabetes. Extreme obesity also puts a parturient at a significantly increased risk of requiring cesarean delivery. For the anesthesiologist, the physiologic changes of obesity combined with the normal physiologic changes of pregnancy can make for a complex and challenging case. This review will focus on the anesthetic approach to the extremely obese parturient undergoing scheduled operative delivery. With proper planning and a detailed understanding of the patient's comorbidities, a safe and effective anesthetic can be achieved.

Changes in BMI before and during economic development and subsequent risk of cardiovascular disease and total mortality: a 35-year follow-up study in China

OBJECTIVE

It is unclear whether changes in BMI during rapid economic development influence subsequent mortality.

RESEARCH DESIGN AND METHODS

We analyzed whether BMI in 1976 and 1994 and changes in BMI during 1976-1994 predict cardiovascular disease (CVD) and all-cause mortality in a 35-year follow-up cohort of 1,696 Chinese (1,124 men and 572 women, aged 35-65 years) in Xi'an, China. Participants were categorized as underweight (<18.5 kg/m(2)), normal weight (18.5-24.9 kg/m(2)), and overweight (≥25.0 kg/m(2)).

RESULTS

During 51,611 person-years of follow-up, we identified 655 deaths from all causes and 234 from CVD. From 1976 to 1994, the prevalence of overweight rose from 9.2 to 27.8%. With each unit increment in 1976 BMI, multivariate hazard ratios (HRs) (95% CI) were 0.78 (0.72-0.84) for CVD and 0.91 (0.87-0.95) for all-cause mortality. In contrast, corresponding HRs were 1.14 (1.08-1.19) and 1.05 (1.01-1.08) in 1994 BMI. The HRs for each unit increment in BMI change from 1976 to 1994 were 1.35 (1.25-1.41) for CVD and 1.09 (1.05-1.13) for all-cause mortality. Compared with participants with stable normal weight in 1976 and 1994, HRs of all-cause mortality for those who had normal weight in 1976 but became overweight in 1994 and for those who were persistently overweight during 1976-1994 were 1.42 (1.12-1.80) and 1.80 (1.04-3.14), respectively.

CONCLUSIONS

Gaining weight with increased BMI at middle age in Chinese during economic development was associated with elevated risks of all-cause and CVD mortality. Higher BMI measured before economic development was associated with lower mortality risk, whereas BMI measured afterward was associated with increased mortality.

Visceral adiposity and skeletal muscle mass are independently and synergistically associated with left ventricular structure and function: the Korean Genome and Epidemiology Study

BACKGROUND

Obesity and low muscle mass may coexist as age-related changes in body composition. We aimed to investigate the effect of visceral adiposity and skeletal muscle mass on left ventricular (LV) structure and function in the general population.

METHODS

A total of 1941 participants without known cardiovascular disease were enrolled from the Korean Genome and Epidemiology Study. Visceral fat area (VFA) was assessed by computed tomography. Appendicular skeletal muscle mass (ASM) was estimated by dual-energy X-ray absorptiometry and was used as a percentage of body weight (ASM/Wt). LV structure and function were assessed by tissue Doppler imaging (TDI) echocardiography.

RESULTS

Across VFA tertiles, ASM increased, but ASM/Wt decreased (all P<0.001). In multivariate models adjusted for conventional cardiovascular risk factors, LV mass index and LV diastolic parameters, such as left atrial dimension, TDI Ea velocity, and E/Ea ratio, were significantly impaired as VFA increased. On the other hand, an increase in ASM/Wt was associated with a decrease in LV mass index and improvement of LV diastolic parameters. With regard to LV mass index and TDI Ea velocity, VFA and ASM/Wt showed synergistic effects (all P interaction<0.05). When both VFA and ASM/Wt were simultaneously included in the same model, both remained independent predictors of LV mass index and TDI Ea velocity.

CONCLUSIONS

More visceral fat and less muscle mass are independently and synergistically associated with an increase in LV mass index and impairment of LV diastolic parameters. Further research is needed to explore the complex mechanisms underlying these associations.

The obesity paradox in surgical intensive care patients with peritonitis

PURPOSE

Although obesity is usually regarded as a risk factor in surgical patients, various observations have revealed a better outcome in the obese. This finding is called the obesity paradox. To which group of patients the paradox applies and even whether it exists at all are matters of controversial discussion.

MATERIALS AND METHODS

We retrospectively analyzed 253 consecutive patients with surgical peritonitis and sepsis who needed intensive care for more than 2 days postoperative. Patients were assigned to groups according to body mass index (BMI), and groups were compared with respect to outcome parameters.

RESULTS

In the 4 BMI groups--less than 21, 21 to 25, 26 to 30, and more than 30 kg/m(2)--mortality rate at 28 days was 73%, 50%, 42%, and 31%, respectively. The relative risk of death at 28 days in the BMI greater than 30 kg/m(2) group compared to the normal weight group (BMI, 21-25.9 kg/m(2)) was 0.66 (95% confidence interval, 0.28-0.94). However, mortality rate at 5 years was 90%, 70%, 69%, and 75%, respectively. Patients in the lowest BMI range were less likely to be discharged home. Intensive care unit and hospital length of stay was longest in the group of highest BMI, and that group had the best mean survival (386 days for BMI >30 kg/m(2) vs 113 days for BMI <21 kg/m(2)).

CONCLUSIONS

The "obesity paradox" may exist in patients with surgical peritonitis. Short-term but not long-term outcomes were improved in the obese. Concerns about obesity as a special risk factor in patients with peritonitis are not warranted according to our findings.

Predictors of weight loss in obese older adults: findings from the USA and the UK

OBJECTIVE

To examine the prevalence and demographic predictors of clinically meaningful weight loss in community samples of obese older adults in the USA and the UK.

METHODS

Data were from obese older adults (BMI ≥ 30 kg/m(2); age ≥ 52 years), free of a cancer diagnosis, from the Health and Retirement Study (HRS; n = 3398) and the English Longitudinal Study of Ageing (ELSA; n = 998). Weight change was assessed from 2004 to 2008. Multivariable logistic regression tested whether age, sex, ethnicity, marital status, education, or BMI predicted ≥ 5% weight loss.

RESULTS

Over a quarter (28.7%) of obese participants from HRS and 16.6% from ELSA lost ≥ 5% weight. Being female (odds ratio (OR) = 1.31, 95% confidence interval (CI) = 1.11-1.54) and heavier (BMI ≥ 35 kg/m(2)) (OR = 1.60, 95% CI = 1.37-1.87) predicted weight loss in HRS. Trends were similar in ELSA (female: OR = 1.18, 95% CI = 0.83-1.69; BMI ≥ 35 kg/m(2): OR = 1.24, 95% CI = 0.85-1.82). ORs were increased in ≥ 65-year-olds in HRS (OR = 1.55, 95% CI = 1.33-1.81), and reduced in married people in ELSA (OR = 0.69, 95% CI = 0.48-1.00). Neither education nor ethnicity predicted weight loss in either cohort.

CONCLUSION

A high proportion of obese older adults experience clinically meaningful weight loss, but few demographic variables consistently predict weight loss in this population.

Modulation of adiponectin as a potential therapeutic strategy

Adiponectin is produced predominantly by adipocytes and plays an important role in metabolic and cardiovascular homeostasis through its insulin-sensitizing actions and anti-inflammatory and anti-atherogenic properties. Recently, it has been observed that lower levels of adiponectin can substantially increase the risk of developing type 2 diabetes, metabolic syndrome, atherosclerosis, and cardiovascular disease in patients who are obese. Circulating adiponectin levels are inversely related to the inflammatory process, oxidative stress, and metabolic dysregulation. Intensive lifestyle modifications and pharmacologic agents, including peroxisome proliferator-activated receptor-γ or α agonists, some statins, renin-angiotensin-aldosterone system blockers, some calcium channel blockers, mineralocorticoid receptor blockers, new β-blockers, and several natural compounds can increase adiponectin levels and suppress or prevent disease initiation or progression, respectively, in cardiovascular and metabolic disorders. Therefore, it is important for investigators to have a thorough understanding of the interventions that can modulate adiponectin. Such knowledge may lead to new therapeutic approaches for diseases such as type 2 diabetes, metabolic syndrome, cardiovascular disease, and obesity. This review focuses on recent updates regarding therapeutic interventions that might modulate adiponectin.

Mechanisms linking excess adiposity and carcinogenesis promotion

Obesity constitutes one of the most important metabolic diseases being associated to insulin resistance development and increased cardiovascular risk. Association between obesity and cancer has also been well established for several tumor types, such as breast cancer in post-menopausal women, colorectal, and prostate cancer. Cancer is the first death cause in developed countries and the second one in developing countries, with high incidence rates around the world. Furthermore, it has been estimated that 15-20% of all cancer deaths may be attributable to obesity. Tumor growth is regulated by interactions between tumor cells and their tissue microenvironment. In this sense, obesity may lead to cancer development through dysfunctional adipose tissue and altered signaling pathways. In this review, three main pathways relating obesity and cancer development are examined: (i) inflammatory changes leading to macrophage polarization and altered adipokine profile; (ii) insulin resistance development; and (iii) adipose tissue hypoxia. Since obesity and cancer present a high prevalence, the association between these conditions is of great public health significance and studies showing mechanisms by which obesity lead to cancer development and progression are needed to improve prevention and management of these diseases.