Prospective study of intentional weight loss and mortality in overweight white men aged 40-64 years

Weight science: evaluating the evidence for a paradigm shift

Current guidelines recommend that "overweight" and "obese" individuals lose weight through engaging in lifestyle modification involving diet, exercise and other behavior change. This approach reliably induces short term weight loss, but the majority of individuals are unable to maintain weight loss over the long term and do not achieve the putative benefits of improved morbidity and mortality. Concern has arisen that this weight focus is not only ineffective at producing thinner, healthier bodies, but may also have unintended consequences, contributing to food and body preoccupation, repeated cycles of weight loss and regain, distraction from other personal health goals and wider health determinants, reduced self-esteem, eating disorders, other health decrement, and weight stigmatization and discrimination. This concern has drawn increased attention to the ethical implications of recommending treatment that may be ineffective or damaging. A growing trans-disciplinary movement called Health at Every Size (HAES) challenges the value of promoting weight loss and dieting behavior and argues for a shift in focus to weight-neutral outcomes. Randomized controlled clinical trials indicate that a HAES approach is associated with statistically and clinically relevant improvements in physiological measures (e.g., blood pressure, blood lipids), health behaviors (e.g., eating and activity habits, dietary quality), and psychosocial outcomes (such as self-esteem and body image), and that HAES achieves these health outcomes more successfully than weight loss treatment and without the contraindications associated with a weight focus. This paper evaluates the evidence and rationale that justifies shifting the health care paradigm from a conventional weight focus to HAES.

Interpreting the epidemiological evidence linking obesity and cancer: A framework for population-attributable risk estimations in Europe

Standard approaches to estimating population-attributable risk (PAR) include modelling estimates of exposure prevalence and relative risk. Here, we examine the associations between body mass index (BMI) and cancer risk and how effect modifications of these associations impact on PAR estimates. In 2008, sex- and population-specific risk estimates were determined for associations with BMI in a standardised meta-analysis for 20 cancer types. Since then, refinements of these estimates have emerged: (i) absence of menopausal hormonal therapy (MHT) is associated with elevated BMI associations in post-menopausal breast, endometrial and ovarian cancers; (ii) current smoking attenuates the BMI associations in oesophageal squamous cell carcinoma, lung and pancreatic cancers; (iii) prostate screening attenuates BMI associations when all prostate cancers are considered together; and (iv) BMI is differentially associated with different histological subtypes within the same cancer group. Using secondary analyses of the aforementioned meta-analysis, we show 2-3-fold shifts in PAR estimations for breast and endometrial cancers depending on the MHT usage in European countries. We also critically examine how to best handle exposures (in this example, BMI distributions) and relative risk estimates in PAR models, and argue in favour of a counterfactual approach based around BMI means. From these observations, we develop a research framework in which to optimally evaluate future trends in numbers of new cancers attributable to excess BMI. Overall, this framework gives conservative estimates for PAR - nonetheless, the numbers of avoidable cancers across Europe through avoidance of excess weight are substantial.

Metabolic surgery and cancer: protective effects of bariatric procedures

The worldwide epidemic of obesity and the global incidence of cancer are both increasing. There is now epidemiological evidence to support a correlation between obesity, weight gain, and some cancers. Metabolic or bariatric surgery can provide sustained weight loss and reduced obesity-related mortality. These procedures can also improve the metabolic profile to decrease cardiovascular risk and resolve diabetes in morbidly obese patients. The operations offer several physiological steps, the so-called BRAVE effects: 1) bile flow alteration, 2) reduction of gastric size, 3) anatomical gut rearrangement and altered flow of nutrients, 4) vagal manipulation and 5) enteric gut hormone modulation. Metabolic operations are also associated with a significant reduction of cancer incidence and mortality. The cancer-protective role of metabolic surgery is strongest for female obesity-related tumors; however, the underlying mechanisms may involve both weight-dependent and weight-independent effects. These include the improvement of insulin resistance with attenuation of the metabolic syndrome as well as decreased oxidative stress and inflammation in addition to the beneficial modulation of sex steroids, gut hormones, cellular energetics, immune system, and adipokines. Elucidating the precise metabolic mechanisms of cancer prevention by metabolic surgery can increase our understanding of how obesity, diabetes, and metabolic syndrome are associated with cancer. It may also offer novel treatment strategies in the management of tumor generation and growth.

Weight change in later life and risk of death amongst the elderly: the European Prospective Investigation into Cancer and Nutrition-Elderly Network on Ageing and Health study

OBJECTIVE

Later life weight change and mortality amongst elders.

DESIGN

Nested case-control study.

SETTING

Six countries from the European Investigation into Cancer and nutrition-Elderly, Network on Ageing and Health.

SUBJECTS

A total of 1712 deceased (cases) and 4942 alive (controls) were selected from 34,239 participants, > or = 60 years at enrolment (1992-2000) who were followed-up until March 2007. Annual weight change was estimated as the weight difference from recruitment to the most distant from-date-of-death re-assessment, divided by the respective time.

OUTCOME MEASURES

Mortality in relation to weight change was examined using conditional logistic regression.

RESULTS

Weight loss > 1 kg year(-1) was associated with statistically significant increased death risk (OR = 1.65; 95% CI: 1.41-1.92) compared to minimal weight change (+/-1 kg year(-1)). Weight gain > 1 kg year(-1) was also associated with increased risk of death (OR = 1.15; 95% CI: 0.98-1.37), but this was evident and statistically significant only amongst overweight/obese (OR = 1.55; 95% CI: 1.17-2.05). In analyses by time interval since weight re-assessment, the association of mortality with weight loss was stronger for the interval proximal (< 1 year) to death (OR = 3.10; 95% CI: 2.03-4.72). The association of mortality with weight gain was stronger at the interval of more than 3 years and statistically significant only amongst overweight/obese (OR = 1.58; 95% CI: 1.07-2.33). Similar patterns were observed regarding death from circulatory diseases and cancer.

CONCLUSIONS

In elderly, stable body weight is a predictor of lower subsequent mortality. Weight loss is associated with increased mortality, particularly short-term, probably reflecting underlying nosology. Weight gain, especially amongst overweight/obese elders, is also associated with increased mortality, particularly longer term.

Clinical and economic considerations of antiobesity treatment: a review of orlistat

The objective of this study was to review the current knowledge about the use of orlistat from clinical and economic perspectives, and to assess this drug's public health impact. Weight reduction by current antiobesity drugs, compared to placebo, is at most around 5 kg. Orlistat, the most studied antiobesity drug, is associated with the least-severe adverse effects, but compared with other drugs in its class it also delivers the most modest weight loss versus placebo (less than 3 kg). Orlistat appears to have a favorable risk/benefit profile, and cost-effectiveness ratios seem to be within a range that is generally considered acceptable. In the short-term, orlistat is related to reduced diabetes incidence and to slightly improved blood pressure and lipid profiles. Long-term clinical effects have been largely unstudied, however, and this study did not find reports that considered mortality as an endpoint. Given a very low continuation with orlistat treatment in the population and very modest and, apparently, only short-term clinical effects, orlistat is not likely to have a significant impact on the population health. Public health approaches of improving environmental and social factors to foster healthier food choices and increase physical activity remain essential for addressing the obesity epidemic.

Obesity and gastrointestinal cancer

BACKGROUND

There is emerging evidence of a strong association between obesity and gastrointestinal cancer. This review summarizes the evidence from an epidemiological and pathophysiological perspective.

METHODS

Relevant medical literature was identified from searches of PubMed and references cited in appropriate articles were identified. Selection of articles was based on peer review, journal and relevance.

RESULTS

Numerous epidemiological studies consistently identified an increased risk of developing oesophageal adenocarcinoma and colorectal carcinoma in the obese. The association between obesity and other gastrointestinal malignancies was less robust. Sex seems important with respect to cancer risk. Adipose tissue, particularly viscerally located fat, is metabolically active and exerts systemic endocrine effects. Putative pathophysiological mechanisms linking obesity and carcinogenesis include the insulin-like growth factor axis, adipocytokines and sex steroids.

CONCLUSION

A better understanding of the mechanisms that link obesity and cancer may uncover targets for intervention. Tackling obesity may result in a reduction in the incidence in addition to mortality of certain cancers in future.

Weight loss from maximum body weight and mortality: the Third National Health and Nutrition Examination Survey Linked Mortality File

OBJECTIVE

The aim of this longitudinal study is to examine the relationship between weight loss from maximum body weight, body mass index (BMI), and mortality in a nationally representative sample of men and women.

DESIGN

Longitudinal cohort study.

SUBJECTS

In all, 6117 whites, blacks, and Mexican-Americans 50 years and over at baseline who survived at least 3 years of follow-up, from the Third National Health and Nutrition Examination Survey Linked Mortality Files (1988-1994 with passive mortality follow-up through 2000), were included.

MEASUREMENTS

Measured body weight and self-reported maximum body weight obtained at baseline. Weight loss (maximum body weight minus baseline weight) was categorized as <5%, 5-<15%, and >or=15%. Maximum BMI (reported maximum weight (kg)/measured baseline height (m)(2)) was categorized as healthy weight (18.5-24.9), overweight (25.0-29.9), and obese (>or=30.0).

RESULTS

In all, 1602 deaths were identified. After adjusting for age, race, smoking, health status, and preexisting illness, overweight men with weight loss of 15% or more, overweight women with weight loss of 5-<15%, and women in all BMI categories with weight loss of 15% or more were at increased risk of death from all causes compared with those in the same BMI category who lost <5%; hazard ratios ranged from 1.46 to 2.70. Weight loss of 5-<15% reduced risk of death from cardiovascular diseases among obese men.

CONCLUSIONS

Weight loss of 15% or more from maximum body weight is associated with increased risk of death from all causes among overweight men and among women regardless of maximum BMI.

Physical activity at midlife in relation to successful survival in women at age 70 years or older

BACKGROUND

Physical activity is associated with reduced risks of chronic diseases and premature death. Whether physical activity is also associated with improved overall health among those who survive to older ages is unclear.

METHODS

A total of 13,535 Nurses' Health Study participants who were free of major chronic diseases at baseline in 1986 and had survived to age 70 years or older as of the 1995-2001 period made up the study population. We defined successful survival as no history of 10 major chronic diseases or coronary artery bypass graft surgery and no cognitive impairment, physical impairment, or mental health limitations.

RESULTS

After multivariate adjustment for covariates, higher physical activity levels at midlife, as measured by metabolic-equivalent tasks, were significantly associated with better odds of successful survival. Significant increases in successful survival were observed beginning at the third quintile of activity: odds ratios (ORs) (95% confidence intervals [CIs]) in the lowest to highest quintiles were 1 [Reference], 0.98 (0.80-1.20), 1.37 (1.13-1.65), 1.34 (1.11-1.61), and 1.99 (1.66-2.38) (P < .001 for trend). Increasing energy expenditure from walking was associated with a similar elevation in odds of successful survival: the ORs (95% CIs) of successful survival across quintiles of walking were 1 [Reference], 0.99 (0.80-1.21), 1.19 (0.97-1.45), 1.50 (1.24-1.82), and 1.47 (1.22-1.79) (P < .001 for trend).

CONCLUSION

These data provide evidence that higher levels of midlife physical activity are associated with exceptional health status among women who survive to older ages and corroborate the potential role of physical activity in improving overall health.

The effect of randomization to weight loss on total mortality in older overweight and obese adults: the ADAPT Study

BACKGROUND

Although weight loss reduces risk for comorbid diseases, many observational studies suggest that weight loss is associated with increased mortality risk, leading to reluctance by clinicians to consider weight reduction as a strategy to maintain health and independence in older adults. However, whether the observed weight loss is intentional is difficult to determine and may not accurately represent the mortality risk associated with intentional weight reduction. Data from the Arthritis, Diet, and Activity Promotion Trial (ADAPT) were used to determine whether randomization to a weight reduction program was associated with total mortality in overweight/obese older adults.

METHODS

ADAPT (n = 318; mean age 69 +/- 6 years, body mass index 34 +/- 5 kg/m2, 72% female) assessed the influence of weight loss (achieved through dietary counseling and lifestyle modification) and/or exercise on function in overweight/obese older adults with knee osteoarthritis. ADAPT ended in December 1999. Participant vital was ascertained status through December 2006 using the National Death and Social Security Indexes.

RESULTS

The mortality rate for those randomized to the 18-month weight loss intervention (n = 159, mean weight loss = -4.8 kg, 15 deaths) was lower than that for those not randomized to the weight loss intervention (n = 159, mean weight loss = -1.4 kg, 30 deaths; hazard rate ratio = 0.5, 95% confidence interval 0.3-1.0). Results were not appreciably changed when analyses were stratified by age, gender, baseline weight status, or magnitude of weight loss.

CONCLUSIONS

In older adults, intentional weight loss was not associated with increased total mortality and may reduce mortality risk. Observational studies of weight loss, especially when intentionality cannot be rigorously established, may be misleading with respect to the effect of weight loss on mortality.

Modulating human aging and age-associated diseases

Population aging is progressing rapidly in many industrialized countries. The United States population aged 65 and over is expected to double in size within the next 25 years. In sedentary people eating Western diets aging is associated with the development of serious chronic diseases, including type 2 diabetes mellitus, cancer and cardiovascular diseases. About 80% of adults over 65 years of age have at least one chronic disease, and 50% have at least two chronic diseases. These chronic diseases are the most important cause of illness and mortality burden, and they have become the leading driver of healthcare costs, constituting an important burden for our society. Data from epidemiological studies and clinical trials indicate that many age-associated chronic diseases can be prevented, and even reversed, with the implementation of healthy lifestyle interventions. Several recent studies suggest that more drastic interventions (i.e. calorie restriction without malnutrition and moderate protein restriction with adequate nutrition) may have additional beneficial effects on several metabolic and hormonal factors that are implicated in the biology of aging itself. Additional studies are needed to understand the complex interactions of factors that regulate aging and age-associated chronic disease.

A review and meta-analysis of the effect of weight loss on all-cause mortality risk

Overweight and obesity are associated with increased morbidity and mortality, although the range of body weights that is optimal for health is controversial. It is less clear whether weight loss benefits longevity and hence whether weight reduction is justified as a prime goal for all individuals who are overweight (normally defined as BMI>25 kg/m2). The purpose of the present review was to examine the evidence base for recommending weight loss by diet and lifestyle change as a means of prolonging life. An electronic search identified twenty-six eligible prospective studies that monitored subsequent mortality risk following weight loss by lifestyle change, published up to 2008. Data were extracted and further analysed by meta-analysis, giving particular attention to the influence of confounders. Moderator variables such as reason for weight loss (intentional, unintentional), baseline health status (healthy, unhealthy), baseline BMI (normal, overweight, obese), method used to estimate weight loss (measured weight loss, reported weight loss) and whether models adjusted for physical activity (adjusted data, unadjusted data) were used to classify subgroups for separate analysis. Intentional weight loss per se had a neutral effect on all-cause mortality (relative risk (RR) 1·01; P = 0·89), while weight loss which was unintentional or ill-defined was associated with excess risk of 22 to 39 %. Intentional weight loss had a small benefit for individuals classified as unhealthy (with obesity-related risk factors) (RR 0·87 (95 % CI 0·77, 0·99); P = 0·028), especially unhealthy obese (RR 0·84 (95 % CI 0·73, 0·97); P = 0·018), but appeared to be associated with slightly increased mortality for healthy individuals (RR 1·11 (95 % CI 1·00, 1·22); P = 0·05), and for those who were overweight but not obese (RR 1·09 (95 % CI 1·02, 1·17); P = 0·008). There was no evidence for weight loss conferring either benefit or risk among healthy obese. In conclusion, the available evidence does not support solely advising overweight or obese individuals who are otherwise healthy to lose weight as a means of prolonging life. Other aspects of a healthy lifestyle, especially exercise and dietary quality, should be considered. However, well-designed intervention studies are needed clearly to disentangle the influence of physical activity, diet strategy and body composition, in order to define appropriate advice to those populations that might be expected to benefit.

Effects of bariatric surgery on cancer incidence in obese patients in Sweden (Swedish Obese Subjects Study): a prospective, controlled intervention trial

BACKGROUND

Obesity is a risk factor for cancer. Intentional weight loss in the obese might protect against malignancy, but evidence is limited. To our knowledge, the Swedish Obese Subjects (SOS) study is the first intervention trial in the obese population to provide prospective, controlled cancer-incidence data.

METHODS

The SOS study started in 1987 and involved 2010 obese patients (body-mass index [BMI] >or=34 kg/m(2) in men, and >or=38 kg/m(2) in women) who underwent bariatric surgery and 2037 contemporaneously matched obese controls, who received conventional treatment. While the main endpoint of SOS was overall mortality, the main outcome of this exploratory report was cancer incidence until Dec 31, 2005. Cancer follow-up rate was 99.9% and the median follow-up time was 10.9 years (range 0-18.1 years).

FINDINGS

Bariatric surgery resulted in a sustained mean weight reduction of 19.9 kg (SD 15.6 kg) over 10 years, whereas the mean weight change in controls was a gain of 1.3 kg (SD 13.7 kg). The number of first-time cancers after inclusion was lower in the surgery group (n=117) than in the control group (n=169; HR 0.67, 95% CI 0.53-0.85, p=0.0009). The sex-treatment interaction p value was 0.054. In women, the number of first-time cancers after inclusion was lower in the surgery group (n=79) than in the control group (n=130; HR 0.58, 0.44-0.77; p=0.0001), whereas there was no effect of surgery in men (38 in the surgery group vs 39 in the control group; HR 0.97, 0.62-1.52; p=0.90). Similar results were obtained after exclusion of all cancer cases during the first 3 years of the intervention.

INTERPRETATION

Bariatric surgery was associated with reduced cancer incidence in obese women but not in obese men.

FUNDING

Swedish Research Council, Swedish Foundation for Strategic Research, Swedish Federal Government under the LUA/ALF agreement, Hoffmann La Roche, Cederoths, AstraZeneca, Sanofi-Aventis, Ethicon Endosurgery.

Weight cycling and mortality among middle-aged or older women

BACKGROUND

Controversy exists about whether weight cycling increases morbidity and mortality.

METHODS

To assess the independent association of weight cycling with mortality, we conducted a prospective study of 44 882 middle-aged or older women in the Nurses' Health Study who provided information on intentional weight losses between 1972 and 1992, survived until at least 1994, had a body mass index (calculated as weight in kilograms divided by height in meters squared) of at least 17, and had no history of cancer (other than nonmelanoma skin cancer) or heart disease. Women who reported they had intentionally lost at least 9.1 kg at least 3 times were classified as severe weight cyclers. Women who had intentionally lost at least 4.5 kg at least 3 times but did not meet the criteria for severe weight cycling were classified as mild weight cyclers. All-cause mortality and cardiovascular mortality were assessed.

RESULTS

Between 1972 and 1992, approximately 18.8% of the women were mild weight cyclers, and 8.0% were severe weight cyclers. During 12 years of follow-up, 2884 women died; of their deaths, 425 were due to cardiovascular events. Weight cyclers gained more weight during follow-up than noncyclers (P < .001). After adjusting for BMI at age 18 years, physical activity, smoking, postmenopausal hormone replacement therapy, alcohol intake, net weight change from age 18 years, and change in physical activity, there was no increase in risk of all-cause mortality among mild (relative risk [RR], 0.83; 95% confidence interval [CI], 0.75-0.93) or severe cyclers (RR, 0.89; 95% CI, 0.77-1.04). Similar results were observed for cardiovascular mortality and among women 70 years or younger.

CONCLUSION

Repeated intentional weight losses were not predictive of greater all-cause or cardiovascular mortality.

Cancer incidence and mortality after gastric bypass surgery

Despite weight loss recommendations to prevent cancer, cancer outcome studies after intentional weight loss are limited. Recently, reduced cancer mortality following bariatric surgery has been reported. This study tested whether reduced cancer mortality following gastric bypass was due to decreased incidence. Cancer incidence and mortality data through 2007 from the Utah Cancer Registry (UCR) were compared between 6,596 Utah patients who had gastric bypass (1984-2002) and 9,442 severely obese persons who had applied for Utah Driver's Licenses (1984-2002). Study outcomes included incidence, case-fatality, and mortality for cancer by site and stage at diagnosis of all gastric bypass patients, compared to nonoperated severely obese controls. Follow-up was over a 24-year period (mean 12.5 years). Total cancer incidence was significantly lower in the surgical group compared to controls (hazard ratio (HR) = 0.76; confidence interval (CI) 95%, 0.65-0.89; P = 0.0006). Lower incidence in surgery patients vs. controls was primarily due to decreased incidence of cancer diagnosed at regional or distant stages. Cancer mortality was 46% lower in the surgery group compared to controls (HR = 0.54; CI 95%, 0.37-0.78; P = 0.001). Although the apparent protective effect of surgery on risk of developing cancer was limited to cancers likely known to be obesity related, the inverse association for mortality was seen for all cancers. Significant reduction in total cancer mortality in gastric bypass patients compared with severely obese controls was associated with decreased incidence, primarily among subjects with advanced cancers. These findings suggest gastric bypass results in lower cancer risk, presumably related to weight loss, supporting recommendations for reducing weight to lower cancer risk.

Intentional weight loss and mortality among initially healthy men and women

Most prospective observational studies suggest that weight loss increases the risk of premature death among obese individuals. This is surprising because clinical studies show that weight loss generally leads to overall improvements in cardiovascular risk factors. It is sometimes argued that the increased mortality observed with weight loss must depend on confounding or poor study designs. This review was conducted to summarize results from studies on intentional weight loss and mortality among healthy individuals, while carefully considering the designs and problems in these studies. Evaluation criteria with a rating scale were developed. Of the studies evaluated, two found decreased mortality with intentional weight loss, three found increased mortality, and four found no significant associations between intentional weight loss and total mortality. Thus, it is still not possible for health authorities to make secure recommendations on intentional weight loss. More studies designed to specifically address this issue are warranted.

Chitosan for overweight or obesity

BACKGROUND

Chitosan, a deacetylated chitin, is a dietary supplement reported to decrease body weight. It is widely available over the counter worldwide and although evaluated in a number of trials its efficacy remains in dispute.

OBJECTIVES

To assess the effects of chitosan as a treatment for overweight and obesity.

SEARCH STRATEGY

We searched electronic databases (MEDLINE, EMBASE, BIOSIS, CINAHL, The Cochrane Library), specialised web sites (Controlled Trials, IBIDS, SIGLE, Reuter's Health Service, Natural Alternatives International, Pharmanutrients), bibliographies of relevant journal articles, and contacted relevant authors and manufacturers.

SELECTION CRITERIA

Trials were included in the review if they were randomised controlled trials of chitosan for a minimum of four weeks duration in adults who were overweight or obese. Authors of included studies were contacted for additional information where appropriate.

DATA COLLECTION AND ANALYSIS

Details from eligible trials were extracted independently by two reviewers using a standardised data extraction form. Differences in data extraction were resolved by consensus. Continuous data were expressed as weighted mean differences and standard deviations. The pooled effect size was computed by using the inverse variance weighted method.

MAIN RESULTS

Fifteen trials including a total of 1219 participants met the inclusion criteria. No trial to date has measured the effect of chitosan on mortality or morbidity. Analyses indicated that chitosan preparations result in a significantly greater weight loss (weighted mean difference -1.7 kg; 95% confidence interval (CI) -2.1 to -1.3 kg, P < 0.00001), decrease in total cholesterol (-0.2 mmol/L [95% CI -0.3 to -0.1], P < 0.00001), and a decrease in systolic and diastolic blood pressure compared with placebo. There were no clear differences between intervention and control groups in terms of frequency of adverse events or in faecal fat excretion. However, the quality of many studies was sub-optimal and analyses restricted to studies that met allocation concealment criteria, were larger, or of longer duration showed that such trials produced substantially smaller decreases in weight and total cholesterol.

AUTHORS' CONCLUSIONS

There is some evidence that chitosan is more effective than placebo in the short-term treatment of overweight and obesity. However, many trials to date have been of poor quality and results have been variable. Results obtained from high quality trials indicate that the effect of chitosan on body weight is minimal and unlikely to be of clinical significance.

Weight change and cancer risk in a cohort of more than 65,000 adults in Austria

BACKGROUND

To investigate relations between weight loss or weight gain and the incidence of cancer.

PATIENTS AND METHODS

Weight change was assessed in a population-based cohort of >65 000 Austrian adults (28 711 men and 36 938 women) for a period of 7 years, after which participants were followed for incident cancers over 8 years on average. Incident cancers (other than nonmelanoma skin cancers) were ascertained by a population-based cancer registry (n = 3128). Cox proportional hazards models were used to estimate hazard rate ratios (HRs) stratified by age and adjusted for smoking, occupational group, blood glucose and body mass index at baseline.

RESULTS

In both men and women, neither weight loss nor weight gain was clearly associated with the incidence of all cancers combined. Weight loss (>0.10 kg/m(2)/year) was inversely associated with colon cancer in men [HR 0.50; 95% confidence interval (CI) 0.29-0.87], while high weight gain (> or =0.50 kg/m(2)/year) was inversely associated with prostate cancer (HR 0.43; 95% CI 0.24-0.76). Among women, high weight gain was positively associated with ovarian cancer (HR 2.48; 95% CI 1.05-5.85).

CONCLUSION

These findings indicate that recent weight change may influence the incidence of several types of cancer.

Eight-year change in body mass index and subsequent risk of cardiovascular disease among healthy non-smoking men

OBJECTIVE

To determine how change in BMI over 8 years is associated with risk of subsequent cardiovascular disease (CVD) among middle aged men.

METHODS

Prospective cohort study among 13,230 healthy men (aged 51.6+/-8.7 years) in the Physicians' Health Study. BMI was collected at baseline in 1982 and after 8 years, at which time follow-up began. Subsequent CVD events were collected and confirmed through March 31, 2005. Cox proportional hazards models evaluated BMI at 8 years and risk of CVD, 8-year change in BMI and risk of CVD, and whether change in BMI added prognostic information after the consideration of BMI at 8 years.

RESULTS

1308 major CVD events occurred over 13.5 years. A higher BMI at year 8 was associated with an increased risk of CVD. Compared to a stable BMI (+/-0.5 kg/m(2)), a 0.5-2.0 kg/m(2) increase had a multivariable-adjusted RR of 1.00 (0.86-1.16). A >/=2.0 kg/m(2) increase had a multivariable-adjusted RR of 1.39 (1.16-1.68), however further adjustment for BMI reduced the RR to 1.00 (0.81-1.23). A decrease in BMI had a multivariable RR of 1.23 (1.07-1.42) which was unaffected by adjustment for BMI at 8 years.

CONCLUSION

A higher BMI and a rising BMI were both associated with an increased risk of CVD, however an increasing BMI did not add prognostic information once current BMI was considered. In contrast, a declining BMI was associated with an increased risk of CVD independent of current BMI.

Long-term weight loss effects on all cause mortality in overweight/obese populations

This systematic review assesses the long-term effectiveness of weight loss on all cause mortality in overweight/obese people. Medline, Embase and Cinahl were searched (1966-2005). Cohort studies and trials on participants with body mass index > or =25 kg m(-2), with weight change and mortality with > or =2-year follow-up, were included finally identifying 11 papers based on eight studies. There may be gender differences in the benefits for all cause mortality. The impact of weight loss in men on mortality was not clear with some studies indicating weight loss to be detrimental, while a recent cohort study showed benefits, if it were a personal decision. Other studies with no gender separation had similarly mixed results. However, one study indicated that overweight/obese women with obesity-related illness, who lost weight intentionally within 1 year, had significantly reduced mortality rates of 19-25%. In contrast, studies of overweight/obese diabetics irrespective of gender showed significant benefit of intentional weight loss on mortality in a meta-analysis, hazard ratios = 0.75 (0.67-0.83). There is some evidence that intentional weight loss has long-term benefits on all cause mortality for women and more so for diabetics. Long-term effects especially for men are not clear and need further investigation.

Selective 5-HT6 receptor ligands: progress in the development of a novel pharmacological approach to the treatment of obesity and related metabolic disorders

The increasing global prevalence of obesity unequivocally demonstrates that neither behavioural (diet and exercise) nor pharmacological approaches to this health problem are working. In this area of high unmet clinical need, the 5-HT6 receptor has generated enormous interest amongst academic and pharmaceutical industry scientists as a molecular target for the development of a new generation of safe and more effective anti-obesity drugs. In this review, we have described the major developments that have occurred in the fields of the medicinal chemistry and pharmacology of 5-HT6 ligands, with particular emphasis on their potential application as novel anti-obesity drugs. The last 5 years have witnessed an increasing understanding of the 5-HT6 receptor and its structural requirements that has produced an explosion in the number and diversity of novel, highly selective 5-HT6 receptor agonists, partial agonists and antagonists that have been designed and synthesized. In animal models, 5-HT6 receptor ligands of all functional types have been shown to decrease food intake when given acutely and chronically, to evoke profound and sustained weight-loss in obese animals, and concomitantly to improve a number of cardio-metabolic risk factors. Comparator studies in obese animal models, which are highly predictive of clinical outcomes, indicate that 5-HT6 ligands may have the potential to be more efficacious in the treatment of obesity than the current generation of anti-obesity drugs.

Effects of bariatric surgery on mortality in Swedish obese subjects

BACKGROUND

Obesity is associated with increased mortality. Weight loss improves cardiovascular risk factors, but no prospective interventional studies have reported whether weight loss decreases overall mortality. In fact, many observational studies suggest that weight reduction is associated with increased mortality.

METHODS

The prospective, controlled Swedish Obese Subjects study involved 4047 obese subjects. Of these subjects, 2010 underwent bariatric surgery (surgery group) and 2037 received conventional treatment (matched control group). We report on overall mortality during an average of 10.9 years of follow-up. At the time of the analysis (November 1, 2005), vital status was known for all but three subjects (follow-up rate, 99.9%).

RESULTS

The average weight change in control subjects was less than +/-2% during the period of up to 15 years during which weights were recorded. Maximum weight losses in the surgical subgroups were observed after 1 to 2 years: gastric bypass, 32%; vertical-banded gastroplasty, 25%; and banding, 20%. After 10 years, the weight losses from baseline were stabilized at 25%, 16%, and 14%, respectively. There were 129 deaths in the control group and 101 deaths in the surgery group. The unadjusted overall hazard ratio was 0.76 in the surgery group (P=0.04), as compared with the control group, and the hazard ratio adjusted for sex, age, and risk factors was 0.71 (P=0.01). The most common causes of death were myocardial infarction (control group, 25 subjects; surgery group, 13 subjects) and cancer (control group, 47; surgery group, 29).

CONCLUSIONS

Bariatric surgery for severe obesity is associated with long-term weight loss and decreased overall mortality.

A food pattern predicting prospective weight change is associated with risk of fatal but not with nonfatal cardiovascular disease

Recently, a food pattern predictive for prospective weight change was identified within the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort. Given the possible impact of weight change on cardiovascular disease (CVD) risk, we examined the association between the above mentioned food pattern and risk of CVD. The analyzed food pattern was defined by a high consumption of whole-grain bread, fruits, fruit juices, grain flakes and/or cereals, and raw vegetables, and a low consumption of processed meat, butter, high-fat cheese, margarine, and meat other than poultry. The associations between quartiles of the food pattern score and CVD morbidity and mortality were examined in 26,238 subjects of the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort using a Cox's Proportional Hazards model for competing risks. During 6.4 y of follow-up, 379 incident cases of CVD were identified, of which 68 were fatal events. The food pattern was not associated with risk of nonfatal CVD. After adjusting for cardiovascular risk factors, the hazard ratios for fatal CVD across increasing quartiles of the score were 1.00, 0.85, 0.31, and 0.47, respectively (P for trend = 0.016). The association of the food pattern with CVD risk differed between fatal and nonfatal events (P for difference = 0.05). These findings from a large German cohort indicate that a food pattern predicting prospective weight change may be associated with the risk of fatal CVD.

Effect of weight loss on predicted cardiovascular risk: change in cardiac risk after bariatric surgery

OBJECTIVE

Our goal was to assess the effect of bariatric surgery on cardiovascular risk estimations of preventable, long-term adverse outcomes.

RESEARCH METHODS AND PROCEDURES

We performed a population-based, historical cohort study between 1990 and 2003 of 197 consecutive patients from Olmsted County, MN, with Class II to III obesity (defined as BMI > or = 35 kg/m2) treated with Roux-en-Y gastric bypass and 163 non-operative patients assessed in a weight-reduction program. We used the observed change in cardiovascular risk factors and risk models derived from data from the National Health and Nutrition Examination Survey (NHANES) I and the NHANES I Epidemiological Follow-up Study (NHEFS) to calculate the predicted impact on cardiovascular events and mortality for the operative and non-operative groups.

RESULTS

Mean follow-up was 3.3 years. Hypertension, diabetes, and dyslipidemia all improved after bariatric surgery. The estimated 10-year risk for cardiovascular events for the operative group decreased from 37% at baseline to 18% at follow-up, while the estimated risk for the non-operative group did not change from 30% at baseline to 30% at follow-up. Risk modeling to predict 10-year outcomes estimated 4 overall deaths and 16 cardiovascular events prevented by bariatric surgery per 100 patients compared with the non-operative group.

CONCLUSIONS

Bariatric surgery induces an improvement in cardiovascular risk factors in patients with Class II to III obesity. Weight loss predicts a major, 10-year reduction in cardiovascular events and deaths. Bariatric surgery should be considered as an alternative approach to reduce cardiovascular risk in patients with Class II to III obesity.

The use of orlistat in the treatment of obesity, dyslipidaemia and Type 2 diabetes

Orlistat (tetrahydrolipstatin) is an inhibitor of gastrointestinal lipases, especially pancreatic lipase. It is used as an adjunct to diet and exercise in order to achieve weight loss in obese individuals (body mass index > 30 kg/m2) or in overweight individuals (body mass index > 27 kg/m2) with other risk factors for atherosclerotic vascular disease, such as hypertension, dyslipidaemia or diabetes. Short- and long-term studies of up to 4 years duration have shown the drug to have significant benefits in weight loss, as well as in the reduction in lipids, glucose and haemoglobin A1c, and in time to onset of Type 2 diabetes compared with diet alone or placebo groups. The incremental amount of weight loss that orlistat produces is modest, but sufficient to result in improvement in obesity comorbidities such as elevated blood pressure, dyslipidaemia and hyperglycaemia compared with diet and exercise alone. Orlistat should only be prescribed for individuals who are motivated to adhere to lifestyle modifications, especially dietary fat restriction.

[Does bariatric surgery cure the metabolic syndrome?]

Metabolic syndrome (MS) is a risk condition for the development of systemic atherosclerotic disease. Morbid obesity is a state of insulin resistance (IR) associated with visceral fat accumulation, which is involved in the development of MS. In severe obesity, conservative therapies promote an improvement of MS, but weight regain is frequent, whereas bariatric surgery promotes a more significant and sustained weight loss. Bariatric surgery is recommended for patients with unsatisfactory response to clinical treatment and with IMC > 40 kg/m(2) or > 35 in case of co-morbidities. In those cases, surgical risk must be acceptable and patients submitted to surgery must be informed about complications and postoperative care. Prevention, improvement and reversion of diabetes (DM2) (70 to 90% of cases) are seen in several bariatric surgery modalities. Disabsorptive are more efficient than restrictive procedures in terms of weight reduction and insulin sensitivity improvement, but chronic complications, such as malnutrition, are also more frequent. Vertical gastroplasty with jejunoileal derivation is a mixed surgery in which the restrictive component predominates. In this modality, reversion of DM2 is due to an increase in insulin sensitivity associated with improved beta cell function. Reversion of MS and its manifestations after bariatric surgery are associated with reduction of cardiovascular mortality and, thus, in severe obesity cases, MS can be considered a surgical condition.

Prediction of cardiovascular and total mortality in Chinese type 2 diabetic patients by the WHO definition for the metabolic syndrome

AIM

The aim of this study is to investigate the prevalence of metabolic syndrome (MES) in type 2 diabetic patients and the predictive values of the World Health Organization (WHO) and National Cholesterol Education Programme (NCEP) definitions and the individual components of the MES on total and cardiovascular mortality.

METHODS

A prospective analysis of a consecutive cohort of 5202 Chinese type 2 diabetic patients recruited between July 1994 and April 2001.

RESULTS

The prevalence of the MES was 49.2-58.1% depending on the use of various criteria. There were 189 deaths (men: 100 and women: 89) in these 5205 patients during a median (interquartile range) follow-up period of 2.1 (0.3-3.6 years). Of these, 164 (87%) were classified as cardiovascular deaths. Using the NCEP criterion, patients with MES had a death rate similar to those without (3.51 vs. 3.85%). By contrast, based on the WHO criteria, patients with MES had a higher mortality rate than those without (4.3 vs. 2.4%, p = 0.002). Compared to patients with neither NCEP- nor WHO-defined MES, only the group with MES defined by the WHO, but not NCEP, criterion had significantly higher mortality rate (2.6 vs. 6.8%, p < 0.001). Using Cox regression analysis, only age, duration of diabetes and smoking were identified as independent factors for cardiovascular or total death. Among the various components of MES, hypertension, low BMI and albuminuria were the key predictors for these adverse events.

CONCLUSIONS

In Chinese type 2 diabetic patients, the WHO criterion has a better discriminative power over the NCEP criterion for predicting death. Among the various components of the MES defined either by WHO or NCEP, hypertension, albuminuria and low BMI were the main predictors of cardiovascular and total mortality.

Associations with weight loss and subsequent mortality risk

PURPOSE

Studies have shown a high prevalence of weight loss in older adults is associated with an increased risk of death. We investigated this in a population-based study.

METHODS

Persons living in Beaver Dam, Wisconsin, participated in a baseline examination between 1988 and 1990 (n=4926). A medical examination and standardized questionnaire were administered. Weight loss was defined as percent loss in body weight from highest lifetime weight to measured weight at baseline.

RESULTS

Weight loss was associated with older age, higher rates of diseases such as diabetes, and lower baseline levels of blood pressure and serum total cholesterol. After controlling for age, medical, and lifestyle factors, both men and women had higher mortality rates over a 10+ year period for increasing categories of weight loss (hazard ratio [ 95% CI]: 1.16 [1.06, 1.27] for men and 1.23 [1.13, 1.34] for women). Increased mortality rates with increasing weight loss was shown in stratified analyses of age, body mass index (BMI) at highest weight, smoking, and disease status, but did not always reach statistical significance. Persons on weight loss diets within the year prior to baseline did not have increased mortality with increasing weight loss.

CONCLUSION

The strong association between weight loss (likely involuntary) and mortality may be a useful way of estimating overall risks to longevity in populations.

Mortality attributable to higher-than-optimal body mass index in New Zealand

OBJECTIVES

To estimate the burden of mortality in New Zealand due to higher-than-optimal body mass index (BMI) in 1997, as well as mortality that could be avoided in 2011 with feasible changes in mean population BMI.

SETTING

New Zealand.

DESIGN

Comparative risk assessment methodology was used to estimate the attributable and avoidable mortality due to high BMI. Outcomes assessed were ischaemic heart disease (IHD), ischaemic stroke, type 2 diabetes mellitus, colorectal cancer and postmenopausal breast cancer.

RESULTS

In 1997, 3154 deaths (11% of all deaths) in New Zealand were due to higher-than-optimal BMI (>21 kg m(-2)). This amounted to 83% of diabetes deaths, 24% of IHD deaths, 15% of ischaemic stroke deaths and 4% of all cancer deaths. If the projected increase in mean population BMI by 2011 was limited to 1.0 kg m(-2) rather than 1.3 kg m(-2), approximately 385 deaths could be prevented annually, mainly from diabetes.

CONCLUSIONS

These results quantify the importance of higher-than-optimal BMI as a major modifiable cause of premature death in New Zealand. Intervention policies that would have only modest effects on slowing the rate of increase in mean population BMI by 2011 could still prevent hundreds of deaths annually.

Obesity in older adults: technical review and position statement of the American Society for Nutrition and NAASO, The Obesity Society

Obesity causes serious medical complications and impairs quality of life. Moreover, in older persons, obesity can exacerbate the age-related decline in physical function and lead to frailty. However, appropriate treatment for obesity in older persons is controversial because of the reduction in relative health risks associated with increasing body mass index and the concern that weight loss could have potential harmful effects in the older population. This joint position statement from the American Society for Nutrition and the NAASO, The Obesity Society reviews the clinical issues related to obesity in older persons and provides health professionals with appropriate weight-management guidelines for obese older patients. The current data show that weight-loss therapy improves physical function, quality of life, and the medical complications associated with obesity in older persons. Therefore, weight-loss therapy that minimizes muscle and bone losses is recommended for older persons who are obese and who have functional impairments or medical complications that can benefit from weight loss.

Weight Change, Weight Change Intention, and the Incidence of Mobility Limitation in Well-Functioning Community-Dwelling Older Adults

BACKGROUND

Obesity increases the risk for functional decline in later years, but the functional consequences of weight change in older adults are currently unclear. The aim of this study was to determine whether weight, weight change, and weight change intention are associated with risk for mobility limitation in elderly persons.

METHODS

This study included 2,932 well-functioning black and white men and women aged 70 to 79 years, participating in the Health, Aging and Body Composition (Health ABC) Study, who were followed for 30 months. At baseline, reported weight change of 5 or more pounds during the previous year and weight change intention were assessed. Mobility limitation was defined as reported difficulty or inability to walk one-quarter mile or to climb 10 steps during two consecutive semiannual assessments during a period of 30 months.

RESULTS

Approximately 30% of participants developed mobility limitation. Higher body mass index (BMI) was associated with increased risk for mobility limitation. Unintentional weight loss in the previous year was associated with increased risk for mobility limitation in the extremely obese, which was defined as BMI >or= 35 (hazard ratios [HR], =3.79; 95% confidence interval [CI], 1.84--7.79), and the normal BMI, which was defined as BMI<25 (HR, 2.55; 95% CI, 1.80--3.60). In persons with BMI 25 to 29.9, intentional weight loss (HR, 1.59; 95% CI, 1.12--2.25) and weight fluctuation with any intention (HR, 1.59; 95% CI, 1.10--2.28) increased the risk for mobility limitation. Unintentional weight gain or fluctuation did not confer additional risk for mobility limitation compared with weight stability, regardless of the level of body weight.

CONCLUSION

In this cohort of well-functioning elderly persons, functional consequences of past weight change depended on the type of weight change, intentionality, and current measured body weight.

Chitosan for overweight or obesity

BACKGROUND

Chitosan, a deacetylated chitin, is a dietary supplement reported to decrease body weight. It is widely available over the counter worldwide and although evaluated in a number of trials its efficacy remains in dispute.

OBJECTIVES

To assess the effects of chitosan as a treatment for overweight and obesity.

SEARCH STRATEGY

We searched electronic databases (MEDLINE, EMBASE, BIOSIS, CINAHL, The Cochrane Library), specialised web sites (Controlled Trials, IBIDS, SIGLE, Reuter's Health Service, Natural Alternatives International, Pharmanutrients), bibliographies of relevant journal articles, and contacted relevant authors and manufacturers. Last searches were completed in March 2004.

SELECTION CRITERIA

Trials were included in the review if they were randomised controlled trials of chitosan a minimum of four weeks duration in adults who were overweight or obese. Authors of included studies were contacted for additional information where appropriate.

DATA COLLECTION AND ANALYSIS

Details from eligible trials were extracted independently by two reviewers using a standardised data extraction form. Differences in data extraction were resolved by consensus. Continuous data were expressed as weighted mean differences and standard deviations. The pooled effect size was computed by using the inverse variance weighted method.

MAIN RESULTS

Fourteen trials including a total of 1131 participants met the inclusion criteria. No trial to date has measured the effect of chitosan on mortality or morbidity. Analyses including all trials indicated that chitosan preparations result in a significantly greater weight loss (weighted mean difference -1.7 kg; 95% confidence interval (CI) -2.1 to -1.3 kg; P < 0.00001), decrease in total cholesterol (-0.2 mmol/L; 95% CI -0.3 to -0.1; P < 0.00001), decrease in systolic (-5.9 mmHg; 95% CI -7.3 to -4.6; P < 0.0001) and diastolic (-3.4 mmHg; 95% CI -4.4 to -2.4; P < 0.00001) blood pressure compared with placebo. There were no clear differences between intervention and control groups in terms of frequency of adverse events or in faecal fat excretion. However, the quality of many studies was sub-optimal and analyses restricted to studies that met allocation concealment criteria, were larger, or of longer duration showed that such trials produced substantially smaller decreases in weight and total cholesterol.

AUTHORS' CONCLUSIONS

There is some evidence that chitosan is more effective than placebo in the short-term treatment of overweight and obesity. However, many trials to date have been of poor quality and results have been variable. Results obtained from high quality trials indicate that the effect of chitosan on body weight is minimal and unlikely to be of clinical significance.

Systematic review of long-term weight loss studies in obese adults: clinical significance and applicability to clinical practice

BACKGROUND

Obesity is a common health problem that requires a long-term care approach. We systematically reviewed long-term (> or =2 y) studies investigating dietary/lifestyle, pharmacologic, and surgical weight loss methods to assess (1) weight loss efficacy, defined by absolute weight loss and the proportion of subjects with > or =5% weight loss, (2) effects of weight loss on cardiovascular risk factors, and (3) applicability of findings from studies to everyday clinical practice.

METHODS

The MEDLINE, HealthSTAR, and the Cochrane Controlled Trials databases were searched for studies investigating the long-term efficacy of weight loss methods in overweight and obese adults. Data were extracted for (i) weight loss after 1 y (pharmacologic studies only), 2 y, 3 y, and 4 y, (ii) proportion of subjects with > or =5% weight loss at the end of follow-up, and (iii) changes (end-of follow-up minus baseline values) in blood lipids, fasting blood glucose, and systolic and diastolic blood pressure.

RESULTS

Dietary/lifestyle therapy provides <5 kg weight loss after 2-4 y, pharmacologic therapy provides 5-10 kg weight loss after 1-2 y, and surgical therapy provides 25-75 kg weight loss after 2-4 y. Weight loss of > or =5% baseline weight is not consistently associated with improvements in cardiovascular risk factors and these benefits appear to be intervention specific and occur mainly in people with concomitant cardiovascular risk factors. Weight loss studies have methodologic limitations that restrict the applicability of findings to unselected obese people assessed in everyday clinical practice. These limitations include an inadequate study duration, large proportions of subjects lost to follow-up, a lack of an appropriate usual care group, and a lack of reporting of outcomes in high-risk subgroups.

CONCLUSIONS

Dietary/lifestyle and pharmacologic weight loss interventions provide modest weight loss, and may improve markers of cardiovascular risk factors although these benefits occur mainly in patients with cardiovascular risks. Studies investigating weight loss have methodologic limitations that restrict the applicability of findings to obese patients assessed in clinical practice.

Intention to lose weight, weight changes, and 18-y mortality in overweight individuals without co-morbidities

BACKGROUND

Weight loss in the obese improves risk factors for cardiovascular diseases and diabetes. However, several studies have shown inconsistent long-term effects of weight loss on mortality. We investigated the influence on mortality of intention to lose weight and subsequent weight changes among overweight individuals without known co-morbidities.

METHODS AND FINDINGS

In 1975, a cohort of individuals reported height, weight, and current attempts (defined as "intention") to lose weight, and in 1981, they reported current weight. Mortality of the 2,957 participants with body mass index > or = 25 kg/m2 in 1975 and without pre-existing or current diseases was followed from 1982 through 1999, and 268 participants died. The association of intention to lose weight in 1975 and actual weight change until 1981 with mortality was analysed while controlling for behavioural and psychosocial risk factors and hypertension as possible confounders. Compared with the group not intending to lose and able to maintain stable weight, the hazard ratios (with 95% confidence intervals) in the group intending to lose weight were 0.84 (0.49-1.48) for those with stable weight, 1.86 (1.22-2.87) for those losing weight, and 0.93 (0.55-1.56) for those gaining weight. In the group not intending to lose weight, hazard ratios were 1.17 (0.82-1.66) for those who did lose weight, and 1.57 (1.08-2.30) for those gaining weight.

CONCLUSION

Deliberate weight loss in overweight individuals without known co-morbidities may be hazardous in the long term. The health effects of weight loss are complex, possibly composed of oppositely acting processes, and need more research.

Overweight and obesity and weight change in middle aged men: impact on cardiovascular disease and diabetes

CONTEXT

The benefit of weight reduction for cardiovascular disease (CVD) outcomes remains uncertain.

OBJECTIVE

To examine the effects of baseline body mass index on major CVD outcomes and diabetes over a 20 year follow up, and of weight change in the first five years over the subsequent 15 years.

DESIGN AND SETTING

A prospective study of British men followed up for 20 years.

PARTICIPANTS

Men aged 40-59 years with no diagnosis of CVD or diabetes (n = 7176) of whom 6798 provided full information on weight change five years later.

OUTCOME MEASURES

Major CVD events (fatal and non-fatal myocardial infarction and stroke, angina, "other" CVD deaths) and diabetes.

RESULTS

During the 20 year follow up there were 1989 major CVD events and 449 incident cases of diabetes in the 7176 men. Risk of major CVD and diabetes increased significantly with increasing overweight and obesity. During the 15 year follow up, weight gain was associated with increased risk of CVD and diabetes. Weight loss was associated with lower risk of diabetes than the stable group irrespective of initial weight. No significant cardiovascular benefit was seen for weight loss in any men, except possibly in considerably overweight (BMI 27.5-29.9 kg/m(2)) younger middle aged men (RR = 0.42; 95% CI 0.22 to 0.81).

CONCLUSION

Long term risk of CVD and diabetes increased significantly with increasing overweight and obesity. Weight loss was associated with significant reduction in risk of diabetes but not CVD, except possibly in considerably overweight younger men. Duration and severity of obesity seem to limit the cardiovascular benefits of weight reduction in older men.

Tratamiento farmacológico de la obesidad

In this clinical observation, we make a small summary of the current state of pharmacological treatment of obesity. The interest in the use of drugs in the treatment of obesity has grown in recent years, upon our knowledge of the biological basis of obesity having increased, and also because non-pharmacological treatments have not succeeded stopping the constant increase of obesity incidence in western countries. Only two drugs are currently approved by the European Agency of the Drug and the FDA (Food and Drug Administration, United States) for the treatment of long-term obesity: sibutramine and orlistat. Pharmacological treatment of obesity should be considered in obese patients (BMI > 30) or overweight (BMI > 27) in presence of comorbidities as diabetes mellitus, hypertension, dyslipemias (7.8); this must not be used as an isolated treatment but together with other basic therapies: diet, physical exercise and psychological support.

Lipid peroxides in obese patients and effects of weight loss with orlistat on lipid peroxides levels

OBJECTIVE

Obesity is a well-known risk factor of atherosclerosis. Recent studies showed that obesity is associated with enhanced lipid peroxidation. The aim of this study is to investigate the effect of weight reduction with orlistat treatment on lipid peroxidation levels. We assessed lipid peroxidation by measuring the concentration of plasma malondialdehyde (MDA).

DESIGN

A randomized, controlled, open-label 6-month study.

SUBJECTS

In total, 36 obese (body mass index (BMI) >30 kg/m2) and 11 healthy age-matched control subjects were enrolled in the study.

MEASUREMENTS

Fasting glucose, triglyceride, total cholesterol, HDL cholesterol and LDL cholesterol and MDA levels were measured in both groups. Obese subjects received orlistat, 120 mg three times daily together with hypocaloric diet. After 6 months of treatment laboratory tests were repeated.

RESULTS

MDA levels were significantly higher in obese patients than the control group (P<0.0001). After 6 months of treatment in obese subjects, the mean weight of the patients decreased by 6.8 kg, the BMI by 3.2 kg/m2. Plasma MDA levels were significantly reduced by weight loss from 2+/-0.77 to 0.89+/-0.41 nmol/ml (P<0.001). BMI correlated with MDA levels at baseline (r=0.6, P<0.0001). Changes in BMI was positively associated with plasma MDA level reduction (r=0.36, P<0.05).

CONCLUSION

These results indicate that obesity is associated with increases in endogenous lipid peroxides. Our data show that the indicator of lipid peroxidation-MDA-falls markedly in association with weight loss with orlistat. The demonstration of decreased free radical generation has important implications for oxidative mechanism underlying obesity-associated disorders.

Intentional weight loss, blood lipids and coronary morbidity and mortality

PURPOSE OF REVIEW

Although weight reduction has been recommended to reduce cardiovascular risk, studies on the association between weight loss and coronary morbidity and mortality show conflicting results. This review summarizes findings from large studies examining this issue and accentuates the importance of carrying out additional well-designed research.

RECENT FINDINGS

Many observational studies report that weight loss in older men and women is associated with increased cardiovascular morbidity and mortality. Recent studies suggest that this association may arise from the confounding effect of preexisting disease. Many studies do not report whether weight loss is intentional or unintentional. Unintentional weight loss may mask beneficial changes in cardiovascular risk due to intentional weight loss. In addition to issues related to the cause of weight loss, use of reported rather than measured weight may bias the results of large studies. However, one recent observational study with a methodology aimed at overcoming these limitations found that individuals who intentionally lost weight experienced a decreased coronary risk.

SUMMARY

Weight reduction in overweight individuals is not universally associated with good health. This is true even if the weight loss results in normal body mass index. Reports of increased coronary risk associated with intentional weight loss may be explained by comorbidities that are also associated with weight loss. Individuals who are overweight and at high coronary risk may benefit from professionally supervised dieting and avoiding regain of lost weight. Clinical trials on cardiovascular outcomes in individuals who lose weight under supervised dieting are needed to assess this recommendation definitively.

The effects of intentional weight loss as a latent variable problem

Although obesity is associated with increased mortality rate and short-term weight loss improves risk factors for mortality, it has not been convincingly shown that weight loss among obese people results in reduced mortality rate. When considering the human literature, it has been pointed out that weight loss is often a sign of illness and that investigators therefore need to separate intentional from unintentional weight loss. It has generally been assumed that among people who state that they do not intend to lose weight, weight change subsequently observed is unintentional. Among such people, weight loss has been consistently associated with increased mortality rate. Complementarily, it has generally been assumed that among people who state that they do intend to lose weight, weight change subsequently observed is intentional. In these people who are intending to lose weight, some studies show apparent benefits of weight loss, some are neutral, and some show deleterious effects. The overall conclusion that some reviewers have drawn from this literature is that intentional weight loss (IWL) is at best not beneficial and may even be harmful with respect to mortality rate. We believe that this conclusion is drawn by inappropriately conflating weight loss (or more generally weight change) among people intending to lose weight with IWL (or change). Herein, under certain assumptions, we: (1) show that the association between mortality rate and weight loss among people intending to lose weight and between mortality rate and IWL are two different things; (2) show that the association between IWL and mortality rate is an inherently unobservable entity; (3) derive a method for estimating the plausible range of true effect of IWL on mortality rate if one is willing to make a number of restrictive, but perhaps reasonable assumptions; and (4) illustrate the method by application to a data set involving middle-age onset calorie restriction in mice.

Effects of orlistat on obesity-related diseases - a six-month randomized trial

AIM

To assess the effect of orlistat on body weight and concomitant diseases in patients with body mass index (BMI) of > 28 kg/m2 and poorly controlled type 2 diabetes, hypertension or hypercholesterolaemia.

METHODS

This trial was a six-month, randomized, double-blind, placebo-controlled study of orlistat 120 mg three times daily plus a mildly reduced-calorie diet. 1004 obese patients (BMI 28-40 kg/m2) were included by 253 private endocrinologists and received orlistat (n = 499) or placebo (n = 505). Patients were stratified by concomitant disorder (type 2 diabetes, n = 193; hypertension, n = 614; hypercholesterolaemia, n = 197). Body weight, anthropometry, lipid and glycaemic control parameters and blood pressure.

RESULTS

After six months, orlistat produced a significantly greater weight loss than placebo in type 2 diabetes (-4.2% vs. -1.4%), hypertension (-6.2% vs. -1.9%) and hypercholesterolaemia (-5.5% vs. -2.3%) groups (p < 0.0001 for all). There was a greater decrease in HbA(1c) in the type 2 diabetes group (-0.54 vs. -0.18%; p = 0.002) and low-density lipoprotein (LDL)-cholesterol in the hypercholesterolaemia group (-11.7% vs. -4.5%; p = 0.004) with orlistat vs. placebo. Early weight loss (> or = 5% at 12 weeks) was associated with the highest weight loss in each group, and the highest decreases in HbA1c, LDL-cholesterol and diastolic blood pressure in patients with type 2 diabetes, hypercholesterolaemia and hypertension, respectively, at six months. The incidence of adverse events was similar for orlistat and placebo, except for certain generally well-tolerated gastrointestinal events that were more common with orlistat.

CONCLUSION

Orlistat plus a mildly reduced-calorie diet produced clinically meaningful weight loss and improvements in risk factors in overweight and obese patients with poorly controlled type 2 diabetes, hypertension or hypercholesterolaemia.

The relationship among physical activity, obesity, and physical function in community-dwelling older women

BACKGROUND

The relationship between obesity and physical function is not well understood. Physical activity may be a key factor impacting on the relationship between obesity and physical function.

METHODS

Subjects included 171 community-dwelling women (mean age = 74.3, SD = 4.3) participating in a 14-year follow-up study to a walking intervention trial. Measures of obesity [body mass index (BMI)] and physical activity (Modified Paffenbarger Questionnaire) were collected in 1982, 1985, 1995, and 1999. Physical function was assessed in 1999 using the Functional Status Questionnaire (FSQ) and gait speed.

RESULTS

Measures of obesity from 1982 to 1995 and measures of physical activity from 1982 to 1995 were related to physical function in 1999. However, hierarchical regression analysis to predict physical function in 1999 controlling for the presence of chronic conditions indicated that physical activity from 1982 to 1995, and not obesity from 1982 to 1995, was an independent predictor of physical function (FSQ: adjusted R2 = 0.09, F = 4.68, P < 0.001; gait speed: adjusted R2 = 18.0, F = 9.41, P < 0.0001.

CONCLUSION

Physical activity appears to be as important if not more important than body weight in predicting future physical function.

Body mass index and short-term weight change in relation to mortality in Dutch women after age 50 y

BACKGROUND

The question of whether weight loss increases a person's longevity is important given the high prevalence of obesity and the large number of people trying to lose weight in industrialized countries.

OBJECTIVE

This study assessed the effect of body mass index (BMI) and weight change (within 1 y of baseline) on subsequent mortality.

DESIGN

This prospective cohort study had a median follow-up of 17 y. Subjects were 8100 women aged 50-66 y who participated in a population-based breast cancer-screening project in the Netherlands between 1974 and 1977. Weight and height were measured during the first and second screening visits. All women were followed until 1996 for causes of death. Cox proportional hazard analyses were conducted for mortality from all causes (n = 1269), cardiovascular disease (CVD; n = 402), and cancer (n = 492).

RESULTS

During follow-up we observed a statistically significant increased risk of mortality from all causes (hazard ratio: 1.4; 95% CI: 1.2, 1.6), cardiovascular disease, and cancer for women in the highest quartile of BMI (in kg/m(2)), > or =27.77. Mortality from all causes, CVD, and cancer did not increase significantly in women with a weight gain of > or =15%. Weight loss was also not significantly related to mortality from all causes, CVD, and cancer.

CONCLUSIONS

Mortality was highest for women in the highest BMI quartile (> or =27.77). Extreme weight gain or weight loss within 1 y was not statistically significantly associated with subsequent higher mortality.

Does intentional weight loss affect mortality rate?

Short-term studies indicate that intentional weight loss among obese persons significantly improves physiologic variables. Hence, it is logical to conjecture that intentional weight loss would lead to long-term benefits and increased longevity. Herein, we review recent epidemiologic studies that investigate the weight loss-mortality association using a conservative analytic approach that included distinguishing between intentional and unintentional weight loss, adjusting for potential confounders, and excluding unhealthy subjects. On balance, results indicate that intentional weight loss appears to neither increase nor decrease mortality rate. Discussion focuses on the problems of addressing this important public health question with observational data.

The effect of weight change on nursing care facility admission in the NHANES I Epidemiologic Followup Survey

Data from the first National Health and Nutrition Examination Survey Epidemiologic Followup Survey were used to examine whether weight change was associated with an increased relative risk of nursing care facility admission. Hazard ratios were calculated with Cox proportional hazards models and stratified by overweight status at baseline. Moderate and large weight loss was associated with an increased risk of nursing care facility admission in overweight and non-overweight subjects. Large weight gain was associated with an increased relative risk in only overweight subjects. In the process of functional decline that results in nursing care facility admission, weight loss may be a sign of acute illness, starvation, or aging. Preventing weight loss may help delay this process of decline. In overweight subjects, preventing weight gain may also be important in delaying this process of decline.