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

Weight loss practices among Malaysian adults

The practice of losing weight is gaining popularity globally with an increase in health consciousness among the general public. A survey was conducted in seven shopping centres in Kuala Lumpur and its neighbouring towns to assess the weight-loss practices of the general public. Out of the 1032 people approached by the researcher, 389 (37.7%) admitted that they had tried to lose weight before. Of these respondents, 50.4% had the wrong perceptions about their weight with 39.1% of the respondents having BMI lower than what they had perceived. The most common weight-loss method used was dieting (89.5%), followed by exercise (81%) and the use of slimming teas (24.9%). Exercise (79.0%) was perceived as the most effective method for losing weight, followed by dieting (71.6%). Most respondents (60.6%) obtained their weight-loss products from the pharmacies but only 34.9% of these respondents had consulted the pharmacists on these products. Therefore, pharmacists should play a more active role in assisting the general public to lose weight successfully and safely.

Weight loss causes increased mortality: pros

There are many good reasons to expect that weight loss in overweight and obese subjects should lead to reduced mortality, not least because the general risk factor profile of several diseases responsible for the excess mortality associated with overweight and obesity improves with weight loss. However, observational long-term population studies have shown that weight loss in overweight subjects leads to increased long-term mortality, even if the studies are well controlled with regard to known confounding factors, including hazardous behaviour and underlying diseases that may lead to both weight loss and increased mortality. It seems unfeasible to wait for the multiple randomized clinical trials of sufficient quality, size and duration that may resolve this question. Therefore, the recommendations about weight loss must be based on the weaker evidence that can be obtained in short-term clinical trials and the observational population studies. Several studies have tried to address the problem by distinguishing intentional from unintentional weight loss, but only few do so by gathering information about the intention to lose weight before weight loss is observed. These studies suggest that intentional weight loss is associated with increased mortality. Recommendations to healthy overweight and obese subjects to lose weight must be based on an explicit weighing of the short-term well-documented benefits of weight loss, including improvement of quality of life, against the possible risk of an increased mortality in the long-term

The relationship between weight loss and all-cause mortality in older men and women with and without diabetes mellitus: the Rancho Bernardo study

OBJECTIVES

To examine the relationship between measured weight change over an approximate 10-year time period on all-cause mortality over the following 12 years in 1,801 community-dwelling men and women (mean age 71 at the beginning of mortality follow-up) with and without diabetes mellitus.

DESIGN

A longitudinal cohort study.

SETTING

A geographically defined community in southern California.

PARTICIPANTS

One thousand eight hundred one older men and women with and without diabetes mellitus.

MEASUREMENTS

Weight, body mass index (BMI), blood pressure, and fasting plasma glucose were measured in 1972-74 (Visit 1) when participants were aged 40 to 79 and again in 1984-87 (Visit 2). Lifetime weight history and dieting for weight control were ascertained in 1985 using a mailed questionnaire. Vital status was determined for the next 12 years, from Visit 2 (1984-87) through 1996. The Cox proportional hazards model was used to assess the age- and multiply adjusted effect of weight change on mortality.

RESULTS

At Visit 1, diabetic men (n = 140) and women (n = 90) were more overweight than nondiabetic men (n = 633) and women (n = 938). Weight gain between Visits 1 and 2 was not a significant predictor of mortality in this cohort. Men and women losing 10 or more pounds between visits had higher age-adjusted death rates during the following 12 years than those with stable weight or weight gain. Weight loss was associated with an increased hazard ratio (HR) for all-cause mortality in nondiabetic men (HR = 1.38, 95% confidence interval (CI) = 1.06-1.80) and women (HR = 1.76, 95% CI = 1.33-2.34) and diabetic men (HR = 3.66, 95% CI = 2.15-6.24) and women (HR = 1.65, 95% CI = 0.70-3.87) after adjustment for age, smoking, and sedentary lifestyle. Significant associations persisted in analyses excluding cigarette smokers and those with depressed mood and low baseline BMI. After excluding those who died within 5 years of the weight loss, the increased HR was statistically significant in men and women with and without diabetes mellitus. Stratified analyses comparing those who reported dieting for weight control with those not dieting showed similar trends, with a higher mortality risk for weight loss in those who lost weight without dieting.

CONCLUSION

In this population of older individuals, weight loss predicted increased all-cause mortality risk not explained by covariates.

Weight change among self-reported dieters and non-dieters in white and African American men and women

Few studies have examined the association between dieting and weight change in general population and results have been inconsistent. To the best of our knowledge, no such study has been done in middle-aged African Americans. We examined 10,554 white and African American men and women who were participants in the Atherosclerosis Risk in Communities (ARIC) Study and attended examinations between 1986 and 1994. We found that the prevalence of dieting in white women, white men, African American women, and African American men was 6.5, 2.3, 3.5, and 0.9%, respectively. After controlling for the covariates, the difference in the mean annual weight gain between dieters and nondieters was 0.61, 0.46, and 0.59 kg/year among white women, white men, and African American women, respectively. In conclusion, in this cohort of white men and women and African American women aged 45-64 years, self-reported dieting was associated with a larger mean annual weight gain than non-dieting over a period of 6 years.

Effects of moderate weight loss on anginal symptoms and indices of coagulation and fibrinolysis in overweight patients with angina pectoris

OBJECTIVE

To evaluate the effects of moderate weight loss, in overweight patients with angina, on plasma coagulation, fibrinolytic indicies and pain frequency.

DESIGN

Single-stranded 12-week dietary intervention, an individualised eating plan with quantitative advice delivered by a dietitian. Target weight loss of 0.5 kg per week.

SETTING

Outpatient research clinic.

SUBJECTS

Fifty-four volunteers with angina pectoris were recruited. Five subjects withdrew, so 27 males, 22 females, mean body mass index (BMI) 29.3 (s.d. 4.3) kg/m(2) and age 60.3 (s.d. 6.5) y completed the intervention.

MEASUREMENTS

Body weight and frequency of anginal pain. Plasma fibrinogen, red cell aggregation (RCA), viscosity, factor VII activity, plasminogen activator inhibitor (PAI) activity, tissue plasminogen activator antigen (t-PA), plasma cholesterol, triglyceride and insulin.

RESULTS

After the 12-week dietary intervention period, mean body weight fell by 3.5 (s.d. 2.6) kg or 4.3% (P=0.0001), range -11.7 to +1.7 kg. Mean angina frequency fell by 1.8 (s.d. 3.6) from 3.2 to 1.4 episodes/week (P=0.009) and plasma cholesterol by 0.4 (s.d. 0.7) from 6.3 to 5.9 mmol/l (P=0.0001). HDL cholesterol and triglyceride were unchanged. Of the coagulation and fibrinolytic factors, factor VII activity and RCA were significantly reduced by 5 (s.d. 20), IU/dl (P=0.04) and 1.3 (s.d. 1.3) arbitrary units (P=0.014), respectively.

CONCLUSIONS

A conventional dietetic intervention, resulting in 4% weight loss, offers the potential to reduce atherosclerotic and thrombotic risk, and to reduce pain frequency, in angina patients. Given the importance of this result in a public health context, these results indicate that this may be a fruitful area for future nutrition research.

Weight-loss attempts and reporting of foods and nutrients, and biomarkers in a national cohort

OBJECTIVE

This study examined the reported intake of foods and nutrients, and biomarkers of dietary exposure and cardiovascular disease in relation to history of trying to lose weight.

METHODS

Dietary, anthropometric and biochemical data were from the third National Health and Nutrition Examination Survey (1988-1994), n=13 092. The history of attempting weight loss variable was created as follows: trying to lose currently and tried in the past 12 months (Y/Y); trying to lose currently, but not tried in the past 12 months (Y/N), not trying currently, but tried in the past 12 months (N/Y); not trying now and not tried in the past 12 months (N/N). Multiple regression methods were used to examine the independent association of history of trying to lose weight with reported intakes of energy, nutrients, percentage energy from low-nutrient-dense foods (sweeteners, baked and dairy desserts, visible fats and salty snacks), and serum concentrations of vitamins, carotenoids and lipids.

RESULTS

Men and women in the Y/Y group reported lower energy intake relative to the N/N group (P<0.0000). However, the reported percentage energy from fat and carbohydrate by the Y/Y group did not differ from the N/N group. Percentage of energy from low-nutrient-dense foods was lower in men in the Y/Y group but not women. The relative odds of reporting the estimated average requirement (EAR) of folate, and vitamins A, B(6), B(12), C, E and iron and adequate intake (AI) of calcium were not adversely affected by history of trying to lose weight in men. In women, the odds of meeting the folate and vitamin E EAR were lower in the Y/Y group. Some history of weight loss categories were significant positive predictors of serum vitamin and carotenoid concentrations, or unrelated to cardiovascular disease risk biomarkers.

CONCLUSIONS

There was little evidence for increased nutritional risk in those reporting repeat attempts at weight loss.

Relationships between changes in weight and changes in cardiovascular risk factors in middle-aged French subjects: effect of dieting

OBJECTIVE

To investigate relationships between changes in weight and changes in cardiovascular risk factors in adults, taking intentionality of weight loss into account.

DESIGN

Longitudinal study in middle-aged French subjects from the SU.VI.MAX cohort.

SUBJECTS

A total of 1773 men (body mass index (BMI) 25.4+/-3.1 kg/m(2), mean+/-s.d) and 2316 women (BMI 23.3+/-3.8 kg/m(2)) aged 45 y and over at baseline.

MEASUREMENTS

Weight, height, blood pressure, serum total cholesterol and fasting blood glucose were measured at baseline and after a 2 y follow-up. Self-reported dieting in order to lose weight, smoking status, leisure-time physical activity, health events and current treatments were assessed through questionnaires.

RESULTS

In multivariate analyses, weight change was positively associated with changes in systolic and diastolic blood pressure (P=0.0002 in women, P=0.0001 in men) and with changes in serum total cholesterol (P=0.008 in women, P=0.02 in men), after adjustment for age, baseline level of each cardiovascular risk factor and current treatments. For example, in men, a weight loss of 5 kg was associated with a decrease of 2.5 mmHg in systolic blood pressure and of 1.5 mmHg in diastolic blood pressure. Taking into account self-reported dieting did not modify these associations.

CONCLUSIONS

In both genders, systolic and diastolic blood pressure and serum cholesterol increased with weight gain and decreased with weight loss, independently of the intentionality to lose weight. At the population level, modest weight loss may have a substantial impact on cardiovascular risk, and preventing even modest weight gain in adults is an important goal in terms of public health.

The enigma of increased non-cancer mortality after weight loss in healthy men who are overweight or obese

OBJECTIVE

To study effects on non-cancer mortality of observational weight loss in middle-aged men stratified for body mass index (BMI), taking a wide range of possible confounders into account.

DESIGN

Prospective, population based study.

SETTING

Male population of Malmö, Sweden.

PARTICIPANTS

In all 5722 men were screened twice with a mean time interval of 6 years in Malmö, southern Sweden. They were classified according to BMI category at baseline (<21, 22-25, overweight: 26-30, and obesity: 30+ kg m(-2)) and weight change category until second screening (weight stable men defined as having a baseline BMI +/- 0.1 kg m(-2) year-1 at follow-up re-screening).

MAIN OUTCOME MEASURES

Non-cancer mortality calculated from national registers during 16 years of follow-up after the second screening. Data from the first year of follow-up were excluded to avoid bias by mortality caused by subclinical disease at re-screening.

RESULTS

The relative risk (RR; 95% CI) for non-cancer mortality during follow-up was higher in men with decreasing BMI in all subgroups: RR 2.64 (1.46-4.71, baseline BMI <21 kg m(-2)), 1.39 (0.98-1.95, baseline BMI 22-25 kg m(-2)), and 1.71 (1.18-2.47, baseline BMI 26+ kg m(-2)), using BMI-stable men as reference group. Correspondingly, the non-cancer mortality was also higher in men with increasing BMI, but only in the obese group (baseline BMI 26+ kg m(-2)) with RR 1.86 (1.31-2.65). In a subanalysis, nonsmoking obese (30+ kg m(-2)) men with decreased BMI had an increased non-cancer mortality compared with BMI-stable obese men (Fischer's test: P=0.001). The mortality risk for nonsmoking overweight men who increased their BMI compared with BMI-stable men was also significant (P=0.006), but not in corresponding obese men (P=0.094). CONCLUSIONS. Weight loss in self-reported healthy but overweight middle-aged men, without serious disease, is associated with an increased non-cancer mortality, which seems even more pronounced in obese, nonsmoking men, as compared with corresponding but weight-stable men. The explanation for these observational findings is still enigmatic but could hypothetically be because of premature ageing effects causing so-called weight loss of involution.

The effect of participation in a weight loss programme on short-term health resource utilization

Obese people consume significantly greater amounts of health resources. This study set out to determine if health resource utilization by obese people decreases after losing weight in a comprehensive medically supervised weight management programme. Four hundred and fifty-six patients enrolled in a single-centred, multifaceted weight loss programme in a universal health care system were studied. Patient information was anonymously linked with administrative databases to measure health resource utilization for 1 year before and after the programme. Mean body mass index (BMI) decreased by more than 15%. The mean annual physician visits (pre = 9.6, post = 9.4) did not change significantly after the programme. However, patients saw a significantly fewer number of different physicians per year following the programme (pre = 4.5, post = 3.9; P < 0.001). Mean annual number of emergency visits (pre = 0.2; post = 0.2) and hospital admissions (pre = 0.05; post = 0.08) did not change. Neither baseline BMI, nor its change during the programme, influenced changes in health resource utilization. Our study suggests that weight loss in a supervised weight management programme does not necessarily decrease short-term health resource utilization. Further study is required to determine if patients who maintain their weight loss experience a decrease in health utilization.

Outcome success in obesity

Intentional weight loss improves many of the medical complications associated with obesity. Moreover, many of these beneficial effects have a dose-dependent relationship with the amount of weight lost and begin after only modest weight losses of 5% to 10% of initial body weight. There is no conclusive evidence that weight loss decreases mortality in obese people. The therapeutic effect of weight loss on risk factors for cardiovascular disease (insulin resistance and diabetes, dyslipidemia, and hypertension) has received the most attention in clinical trials. The hazard of developing coronary heart disease is directly related to the concomitant burden of risk factors. Modest weight loss can affect the entire cluster of risk factors simultaneously. Both negative energy balance and weight loss improve insulin sensitivity and glycemic control in obese patients with type 2 diabetes. Most studies have found that weight loss decreases serum triglyceride, total cholesterol, and low-density lipoprotein cholesterol concentrations and increases serum high-density lipoprotein cholesterol concentration. Regain of weight leads to relapse in triglyceride and cholesterol concentrations. Weight loss, independent of sodium restriction, decreases systolic and diastolic blood pressure. Dietary intervention is the cornerstone of weight-loss therapy. Most diets proposed for losing weight vary in two principal dimensions: energy content and macronutrient composition. Manipulation of food macronutrient content, energy density, and portion size can help decrease energy intake and facilitate weight loss.

Obesity in the elderly

In developed countries, there is a general increase in body weight and body mass index (BMI) with age, until approximately 60 years of age, when body weight and BMI begin to decline. The proportion of intra-abdominal fat, which is related to increased morbidity and mortality, progressively increases with age. There is also a progressive decline in energy intake and daily total energy expenditure (165 kcal/decade in men and 103 kcal/decade in women in developed countries), which is primarily due to a decrease in physical activity, and to a lesser extent, a decrease in basal metabolic rate. The decrease in physical activity is more pronounced in those with chronic disabilities and diseases. The BMI-mortality curves have been reported to move upward (greater overall mortality), become flatter (less effect of BMI on mortality), and in some cases shift to the right (minimum mortality occurs at a higher BMI), for a variety of possible reasons. Weight loss in the elderly has been reported to increase, decrease, or not alter mortality, but the studies are confounded by numerous methodological problems. It has been argued that there may be little benefit in encouraging weight loss in extreme old age (short life expectancy), especially when there are no obesity-related complications or biochemical risk factors and when strong resistance and distress arise from changes in lifelong habits of eating and exercise. In contrast, weight loss in the elderly can reduce morbidity from arthritis, diabetes and other conditions, reduce cardiovascular risk factors, and improve well-being. BMI also predicts morbidity in those without disease. Furthermore, increased physical activity in the elderly, which is an important component of weight management, can produce beneficial effects on muscle strength, endurance, and well-being.

Weight change in old age and its association with mortality

OBJECTIVES

Previous studies of weight change and mortality in older adults have relied on self-reported weight loss, have not evaluated weight gain, or have had limited information on health status. Our objective was to determine whether 5% weight gain or loss in 3 years was predictive of mortality in a large sample of older adults.

DESIGN

Longitudinal observational cohort study.

SETTING

Four U.S. communities.

PARTICIPANTS

Four thousand seven hundred fourteen community-dwelling older adults, age 65 and older.

MEASUREMENTS

Weight gain or loss of 5% in a 3-year period was examined in relationship to baseline health status and interim health events. Risk for subsequent mortality was estimated in those with weight loss or weight gain compared with the group whose weight was stable.

RESULTS

Weight changes occurred in 34.6% of women and 27.3% of men, with weight loss being more frequent than gain. Weight loss was associated with older age, black race, higher weight, lower waist circumference, current smoking, stroke, any hospitalization, death of a spouse, activities of daily living disability, lower grip strength, and slower gait speed. Weight loss but not weight gain of 5% or more was associated with an increased risk of mortality that persisted after multivariate adjustment (Hazard ratio (HR) = 1.67, 95% CI = 1.29-2.15) and was similar in those with no serious illness in the period of weight change. Those with weight loss and low baseline weight had the highest crude mortality rate, although the HR for weight loss was similar for all tertiles of baseline weight and for those with or without a special diet, compared with those whose weight was stable.

CONCLUSIONS

This study confirms that even modest decline in body weight is an important and independent marker of risk of mortality in older adults.

Temporal trends in BMI among adults with diabetes

OBJECTIVE

Increasing obesity within the general population has been accompanied by rising rates of diabetes. The extent to which obesity has increased among people with diabetes is unknown, as are the potential consequences for diabetes outcomes.

RESEARCH DESIGN AND METHODS

Community medical records (hospital and ambulatory) of all Rochester, Minnesota, residents aged > or =30 years who first met standardized research criteria for diabetes from 1970 to 1989 (n = 1,306) were reviewed to obtain data on BMI and related characteristics as of the diabetes identification date (+/-3 months). Vital status as of 31 December 1999 and date of death for those who died were obtained from medical records, State of Minnesota death tapes, and active follow-up.

RESULTS

As of the identification date, data on BMI were available for 1,290 cases. Of the 272 who first met diabetes criteria in 1970-1974, 33% were obese (BMI > or =30), including 5% who were extremely obese (BMI > or =40). These proportions increased to 49% (P < 0.001) and 9% (P = 0.012), respectively, for the 426 residents who first met diabetes criteria in 1985-1989. BMI increased significantly with increasing calendar year of diabetes identification in multivariable regression analysis. Analysis of survival revealed an increased hazard of mortality for BMI > or =41, relative to BMI of 23-25 (hazard ratio 1.60, 95% CI 1.09-2.34, P = 0.016).

CONCLUSIONS

The prevalence of obesity and extreme obesity among individuals at the time they first met criteria for diabetes has increased over time. This is disturbing in light of the finding that diabetic individuals who are extremely obese are at increased risk of mortality compared with their nonobese diabetic counterparts.

Human obesity: an evolutionary approach to understanding our bulging waistline

The unique worldwide spread of the human species and the remarkably long post-reproductive survival show that our genome permits excellent adaptation to vastly different environments. Moreover, the main scourges of later age, namely malignant growths and atherosclerosis, appear in humans later than in shorter-living animals. In recent years, excess weight and obesity have become mass phenomena with a pronounced upward trend in all developed countries. However, despite the detrimental effects of being overweight, these populations live longer than ever, which in part may be explained by the availability of better medical treatment. The prevalence and predicted further spread of obesity can be understood in the light of evolution. In all animal species energy metabolism is asymmetric with energy accumulation ('thrifty genotype') being the necessary condition of survival during hard times. For humans, which are no different to other animals in this respect, this genetic programming was necessary for survival because during the course of history, including the recorded history in the more developed Middle East, Europe or China, there was never a long period of uninterrupted food abundance, whereas famines were regular and frequent. Therefore fat accumulation, when food was available, meant survival at times of shortage, while the possible detrimental effects of overindulgence in food and being overweight expressed in unrealistically old age were irrelevant. It is the central, mostly intra-abdominal fat (in both humans and animals) that is more medically important than the subcutaneous truncal fat, and the accumulation of both types of fat is conditioned by high food consumption; therefore it is a historic novelty for human populations. In contrast, lower-body fat in human females is unique in the animal kingdom: it is much less metabolically active, it is of much lower pathologic significance than central fat, and it is programmed to be mobilized mostly during pregnancy and lactation. In view of all this, norms of desired weight should be based on hard mortality and morbidity statistics and not on theoretical, esthetic or fashion considerations. By this criterion, the upper limit of desirable weight is likely to be body mass index (BMI) 27 or 28, but specified for different populations (sex, race, ethnic origin); moreover, with aging, the detrimental effects of obesity diminish and finally disappear. Risks of other pathologies related to obesity (e.g. diabetes, hypertension and coronary disease) are also population-specific. However, total fatness, measured by BMI, is insufficiently sensitive as a risk factor, and fat distribution (upper-body versus low-body type, as reflected by waist circumference and waist:hip ratio) plays at least as prominent a role. Therefore the detailed norms, not yet available, should take into account both general obesity and fat distribution and be specific for different populations. Since long-term weight loss in adults is rarely achievable, public health measures should be aggressively directed at the prevention of obesity from childhood.

Long-live euthymic BALB/c-nu mice. I. Survival study suggests body weight as a life span predictor

This paper is the first of a series aimed to show the main physiological and pathological characteristics of male euthymic BALB/c-nu mice, a long-live strain of BALB/c mice bred in our own Institute. In particular, the first two paired papers are respectively devoted to general survival information and disease characteristics, also taking into account very old animals that are of high interest for studies on successful aging. In this paper we report the analysis of survival kinetics, the time course of body weight and the correlation between body weight and time-at-death. The longitudinal study has been performed on 88 male mice, checking individually their body weight and date of death and analyzing survival data by a model built by our own. Survival analysis shows quite higher longevity (median age: about 29 months) in this population when compared with other BALB/c strains. The most relevant finding on body weight is its correlation with longevity until the age of 22 months: thinner subjects live longer and lose weight at a lower rate than their heavier mates. Results have formed the basis on which to plan the cross-sectional experiment to study pathologies and biological parameters at different ages, including a group of mice at very advanced ages (34 months).

Factors affecting the use of dietetic services by patients with diabetes mellitus

AIMS

Dietary counselling is vital for patients with diabetes, yet many do not access professional advice. This study investigated the use of dietetic services by patients with diabetes within Sunderland Health District.

METHODS

Diabetic patients were identified from the laboratory module of the Hospital Information System (HIS). Eight thousand five hundred and ninety-seven patients were identified, and cross referenced to dietetic records, producing a comprehensive database for analysis.

RESULTS

Only 58.8% of the sample had dietetic records. Those with records were more likely to be: older (63.8 vs. 61.7 years, P < 0.01); male (52.6% vs. 46.8%, P < 0.05); accessing hospital diabetes services (P < 0.001); to have lipids and renal function checked (both P < 0.001); and to have poor blood glucose control (HbA(1c) > 7.5% to 58.7% vs. 29.9%, P < 0.001). Frequent attenders were most likely to be women, those with poor control, and those with shorter duration of diabetes (P < 0.001). In a logistic regression model, duration of diabetes, insulin treatment, obesity and hyperlipidaemia were the main determinants of increased use.

CONCLUSIONS

This study confirmed that many patients with diabetes do not make use of professional dietetic services, and has highlighted some of the routinely documented characteristics that are associated with use of dietetic services. There appears to be scope to improve uptake of dietetic services by patients with diabetes, and to investigate further individual factors that affect access and attendance.

Epidemiologic data on the relationships of caloric intake, energy balance, and weight gain over the life span with longevity and morbidity

Animal experiments have shown that calorically restricted (CR) animals weigh less and live longer than their ad libitum-fed peers. Are these observations applicable to human beings? This is an important question because the prevalence of obesity in America has increased markedly over recent years. We examine whether there are physiologic effects that occur with CR in humans that could plausibly explain the observed longevity of laboratory animals associated with CR. We also review epidemiologic data from observational and interventional studies on the relationships of caloric intake, energy balance, and weight gain with age-related diseases and longevity. Additionally, data on whether long-term, sustained maintenance of weight loss is feasible, as well as the degree of CR achieved in clinical trials, are summarized. Finally, we provide recommendations regarding further epidemiologic research that will help clarify unanswered questions in these areas.

Orlistat for the treatment of obesity: rapid review and cost-effectiveness model

The aim of this study is to clarify the potential benefits, disbenefits and costs of Orlistat for the treatment of obesity. The method was a search for relevant systematic reviews and randomized controlled trials, in Medline, Pre-Medline, Embase and the Cochrane Library, using Orlistat and its synonyms. Identified trials were appraised using a standard appraisal checklist and trial data were extracted for use in cost-effectiveness modelling. Three large multicentre, randomized placebo controlled trials were included in the rapid review. On average, Orlistat results in obese people losing an additional 3-4% of their initial body weight over diet alone during a 2 year period. There was no strong evidence that this short-term weight loss would have a longer-term impact on morbidity and mortality. The cost utility of Orlistat treatment was estimated at around 46,000 Pounds per Quality Adjusted Life Year gained (extreme values sensitivity analysis 14,000 Pounds to 132,000 Pounds). This rapid review raises some important questions about the potential value of Orlistat in the treatment of obesity. Further research is needed, not only to clarify the longer-term impact of Orlistat treatment, but also to uncover the longer-term impact on mortality and morbidity from short-term weight loss.

Pathophysiology of obesity

The rapidly rising prevalence of obesity, worldwide, has prompted re-evaluations of the definitions and diagnostic criteria, and of the extent of the burden it contributes to health care services. Although categorized arbitrarily for epidemiological purposes according to BMI > 25 kg/m2 ('overweight') and BMI > 30 kg/m2 ('obese'), the disease itself (ICD code E.66) is the process of excess fat accumulation. It leads to multiple organ-specific pathological consequences, particularly if there is a tendency to intra-abdominal fat accumulation. The simplest field method to identify obesity and risk of medical problems is the waist circumference, and this method has found a special role in health promotion. Risks begin with waist > 80 cm (women) or > 94 cm (men). As a broad generalization, obesity produces few symptoms below the age of 40 years, but then several symptoms often develop; tiredness, breathlessness, back pain, arthritis, sweatiness, poor sleeping, depression and menstrual disorders all being common. The symptoms are often attributed to diseases in other body systems. Metabolic diseases like diabetes, hyperlipidaemia and, hypertension develop later, but the mean BMI at diagnosis of diabetes is 28 kg/m2. Ultimately, obesity increases the likelihood of myocardial infarction, stroke and several major cancers, but its biggest impact on health, especially in the elderly, is probably the multiplicity of effects on other body systems. The greatest challenge for public health is to develop effective preventive measures, recognizing that BMI > 25 kg/m2 before the age of 20 years is a very strong predictor of obesity and ill health in adulthood.

Is long-term weight loss possible?

Any intervention which causes negative energy balance is guaranteed to be efficacious in producing weight loss, which will continue while there is negative energy balance or be maintained as long as the new energy balance is maintained. In clinical practice compliance is rarely 100% so the efficiency of even the most efficacious treatment is usually low. However, recent evidence-based guidelines have recognized the clinical benefits of moderate (5-10%) weight loss, which is achievable using a variety of interventions. Long-term studies of 'weight loss' are, in reality, combinations of weight loss (usually completed in 1-6 months) followed by variable weight maintenance, set in the context of progressive adult weight gain in an obesogenic environment. Few studies have adopted specific and separate strategies for weight loss and weight maintenance. Meta-analyses conducted by non-expert methodologists have failed to recognize these distinctions, and have criticized the available research without understanding the different needs of studies with weight change as the outcome variable, which require randomized controlled trials (RCT), and those with weight loss as the treatment, intended to improve metabolic or biomedical outcome measures. An RCT design is inapplicable to studies of biomedical end points (e.g. cardiac risk factors) when weight loss is the treatment. Because fixed weight loss cannot be prescribed there is always a range of weight changes in any study, and single-sample studies with regression analysis provide the best design. An RCT study design does not give useful information about clinical value as the control group is always 'treated' to some extent. Placebo- (or control)-subtracted differences are misleading because in an RCT all subjects recruited to active treatment, including non-responders, are continued on treatment for the full duration of the study. In routine clinical practice, treatments are changed in the light of early experience as a therapeutic trial to optimize the results for each individual, and audit is required to evaluate 'long term weight loss'.

New NHLBI clinical guidelines for obesity and overweight: will they promote health?

OBJECTIVES

The purpose of this study was to assess the justification, on the basis of mortality, of the new National Heart, Lung, and Blood Institute (NHLBI) guidelines on obesity and overweight and to discuss the health implications of declaring all adults with a body mass index of 25 through 29 "overweight."

METHODS

The relationships between NHLBI body mass index categories and mortality for individuals older than 31 years were analyzed for 6253 Alameda County Study respondents aged 21 through 75 years. Time-dependent proportional hazards models were used to adjust for changes in risk factors and weight during follow-up.

RESULTS

Adjusted relative risks of mortality for 4 NHLBI categories compared with the category "normal" indicated that only being underweight or moderately/extremely obese were associated with higher mortality. Specific risk varied significantly by sex.

CONCLUSIONS

Our results are consistent with other studies and fail to justify lowering the overweight threshold on the basis of mortality. Current interpretations of the revised guidelines stigmatize too many people as overweight; fail to account for sex, race/ethnicity, age, and other differences; and ignore the serious health risks associated with low weight and efforts to maintain an unrealistically lean body mass.

Obesity in North America. An overview

The terms "obesity" and "overweight" mean different things to different people. This article discusses such issues as prevalence, morbidity, mortality, and psychosocial effects. Definitions and various classifications of obesity are discussed also.

One-year treatment of obesity: a randomized, double-blind, placebo-controlled, multicentre study of orlistat, a gastrointestinal lipase inhibitor

OBJECTIVE

To assess the efficacy and tolerability of orlistat (Xenical) in producing and maintaining weight loss over a 12-month period.

DESIGN

Patients were randomized to double-blind treatment with either orlistat 120 mg or placebo three times daily, in conjunction with a low-energy diet, for 12 months.

SETTING

Five centres in the UK.

SUBJECTS

228 obese adult patients with body mass index between 30 and 43 kg/m2 and mean weight 97 kg (range 74-144 kg).

INTERVENTIONS

All patients were prescribed a low-energy diet, providing 30% of energy from fat, designed to produce an individually tailored energy deficit of approximately 600 kcal/day, for a run-in period of 4 weeks and then 12 months, plus orlistat 120 mg or placebo three times daily.

MAIN OUTCOME MEASURES

Change in body weight (the primary efficacy parameter), waist circumference and adverse events were reviewed regularly, together with serum lipids, insulin, glucose and plasma levels of fat-soluble vitamins and beta carotene.

RESULTS

Based on an intent-to-treat analysis, after 1 y of treatment patients receiving orlistat had lost an average of 8.5% of their initial body weight compared with 5.4% for placebo-treated patients; 35% of the orlistat group lost at least 5% of body weight compared with 21% of the placebo group (P < 0.05), and 28% and 17%, respectively (P = 0.04) lost at least 10% of body weight. Orlistat-treated patients showed significant decreases (P < 0.05) in serum levels of total cholesterol, low density lipoprotein cholesterol, and in the low density lipoprotein: high density lipoprotein ratio in comparison with placebo. Both groups had similar adverse-event profiles, except for gastrointestinal events, which were 26% more frequent in the orlistat group but were mostly mild and transient. To maintain normal plasma levels of fat-soluble vitamins, supplements of vitamins A, D and E were given to 1.8%, 8.0% and 3.6%, respectively, of orlistat-treated patients, compared with 0.9% of placebo-treated patients for each vitamin type. After 1 y, the decrease in vitamin E and beta carotene was significantly greater in orlistat-treated patients compared with those receiving placebo (P < 0.001). No significant change was found in the mean vitamin E:total cholesterol ratio in either group after 52 weeks.

CONCLUSIONS

Orlistat, in conjunction with a low-energy diet, produced greater and more frequent significant weight loss than placebo during 1 y of treatment. One-third of orlistat-treated patients achieved clinically relevant weight loss (> or = 5% initial body weight). There was also an improvement in relevant serum lipid parameters. Fat-soluble vitamin supplements may be required during chronic therapy. Orlistat was well tolerated and offers a promising new approach to the long-term management of obesity.

A descriptive study of weight loss maintenance: 6 and 15 year follow-up of initially overweight adults

OBJECTIVE

To describe factors associated with long-term maintenance of weight loss.

DESIGN AND SUBJECTS

We identified initially overweight individuals (body mass index >27 kg/m2, n=911) from the nationwide Finnish Twin Cohort and studied those who lost at least 5% of their body weight between 1975 and 1981. Subjects who had maintained weight loss until 1990 (38 men, 17 women) were compared to both regainers (28 men, 26 women) and the other overweight subjects in the cohort.

MEASUREMENTS

Self-report data on weight, height, health behaviours and perceived well-being; self-report and register-based data on health status and use of medication.

RESULTS

Only 6% of all overweight individuals lost and maintained at least 5% weight loss. In men weight loss maintenance was associated with a low level of stress and health-promoting behaviours but also with medical problems. Failure to maintain weight loss seemed to be associated with stressful life and past high alcohol intake. In women weight loss maintenance was associated with low initial well-being and health-compromising behaviours that improved after weight loss.

CONCLUSION

Long-term weight loss maintenance is rare. Predictors of weight loss maintenance are different between women and men. International Journal of Obesity (2000)24, 116-125

The behavioral characteristics of individuals who lose weight unintentionally

OBJECTIVE

To determine whether individuals who unintentionally lost weight differ from individuals who intentionally lost weight in behavioral characteristics related to chronic disease risk factors.

DESIGN

A random-digit dial telephone survey was conducted among a representative sample of American adults (n = 500).

SUBJECTS

Of the 500 individuals sampled, 139 were currently > or = 10% below their lifetime maximum weight. These individuals were asked whether their weight loss was unintentional or intentional. Unintentional (n =49) and intentional (n = 89) weight losers were compared on measures of dietary intake, physical activity, smoking, drinking, and self-reported health status.

RESULTS

Unintentional weight losers had higher levels of smoking and drinking, were less physically active, and were less concerned about their diet and fat intake. Unintentional weight losers did not report having higher levels of disease such as high blood pressure or diabetes. However, unintentional weight losers who reported having such diseases were more likely to report that their weight loss had no effect or had worsened their disorder.

DISCUSSION

Compared to intentional weight losers, those who lost their weight unintentionally reported engaging in more negative health behaviors that are related to disease morbidity and mortality. These data suggest that unintentional weight loss may be part of a cluster of behaviors that have a negative health impact.