Prevalence and trends in obesity among US adults, 1999-2000

Adipokines, inflammation, and the endothelium in diabetes

Cytokines are biologically active low molecular weight proteins that possess several endocrine and metabolic functions and are known products of the immune system and inflammation. Several of these cytokines were shown to be independent risk factors for cerebrovascular and coronary artery disease. Because visceral and subcutaneous adipose tissues are the major sources of cytokines (adipokines), increased adipose tissue mass is associated with alteration in adipokine production (eg, overexpression of tumor necrosis factor-a, interleukin-6, plasminogen activator inhibitor-1, and underexpression of adiponectin in adipose tissue). The proinflammatory status associated with these changes provides a potential link between insulin resistance and endothelial dysfunction, the early stage in the atherosclerotic process, in obese individuals, and in type 2 diabetic patients. Reduction of adipose tissue mass through weight reduction in association with exercise reduces TNF-a, IL-6, and PAI-1, increases adiponectin, and is associated with improved insulin sensitivity and endothelial function.

Depot-medroxyprogesterone acetate injection (Depo-Provera): a highly effective contraceptive option with proven long-term safety

Depot-medroxyprogesterone acetate (Depo-Provera(R)) is a highly effective, nondaily hormonal contraceptive option that has been available in the United States for a decade, and worldwide for 40 years. Benefits and risks of hormonal therapy are often under scrutiny; however, long-term clinical experience has established the safety of this long-acting contraceptive. This article reviews the contraceptive efficacy, potential noncontraceptive health benefits and long-term safety of with regard to risk of cardiovascular events, breast and gynecologic malignancy and osteopenia. Comparisons with other hormonal contraceptives are made as clinically appropriate. Common patient management issues, including effects on menstrual cycle, body weight and mood, are also addressed. Finally, this review provides recommendations for appropriate patient selection.

Therapies for Preventing Heart Failure

Heart failure is an increasingly common syndrome. Despite numerous advances in the treatment of patients with established heart failure, the prevalence and economic burden of the disease will continue to escalate as long as the number of patients with heart failure continues to increase. Much effort has been directed at developing and refining expensive therapies for the small number of patients with advanced heart failure; these efforts will offer little benefit to public health. Simple preventive strategies have been shown to reduce the likelihood of heart failure. Widespread use of these strategies would result in substantial improvement in community health and reduction in societal cost for a disease that will otherwise prove increasingly burdensome.

Serum ghrelin levels in response to glucose load in obese subjects post-gastric bypass surgery

OBJECTIVE

We sought to elucidate further the mechanisms leading to weight loss after gastric bypass (GBP) surgery in morbidly obese individuals. Ghrelin is a gastroenteric appetite-stimulating peptide hormone, fasting levels of which decrease with increasing adiposity and increase with diet-induced weight loss. In addition, ghrelin levels rapidly decline postprandially.

RESEARCH METHODS AND PROCEDURES

We measured serum ghrelin responses to a 75-g oral glucose tolerance test (OGTT) in 6 subjects who had undergone GBP surgery 1.5 +/- 0.7 years before testing and compared these responses with 6 obese subjects about to undergo GBP surgery, 6 obese nonsurgical subjects (matched for BMI to the post-GBP surgical group), and 5 lean subjects.

RESULTS

Despite weight loss induced by the GBP surgery, fasting serum ghrelin levels were significantly lower in the post-GBP surgery group than in the lean subject (by 57%) or pre-GBP surgery (by 45%) group. Serum ghrelin levels during the OGTT were significantly lower in postoperative than in lean, obese pre-GBP surgical, or obese nonsurgical subjects. The magnitude of the decline in serum ghrelin levels between 0 and 120 minutes post-OGTT was significantly smaller in postoperative (by 62%), obese pre-GBP surgical (by 80%), or obese nonsurgical (by 69%) subjects in comparison with lean subjects.

DISCUSSION

Serum ghrelin levels in response to OGTT are lower in subjects post-GBP surgery than in either lean or obese subjects. Tonically low serum ghrelin levels may be involved in the mechanisms inducing sustained weight loss after GBP surgery.

Portrayals of overweight and obese individuals on commercial television

OBJECTIVES

This study examined the distribution and individual characteristics of body types on prime-time television.

METHODS

Five episodes of each of the 10 top-rated prime-time fictional programs on 6 broadcast networks during the 1999-2000 season were quantitatively analyzed.

RESULTS

Of 1018 major television characters, 14% of females and 24% of males were overweight or obese, less than half their percentages in the general population. Overweight and obese females were less likely to be considered attractive, to interact with romantic partners, or to display physical affection. Overweight and obese males were less likely to interact with romantic partners and friends or to talk about dating and were more likely to be shown eating.

CONCLUSIONS

Overweight and obese television characters are associated with specific negative characteristics.

Impact of objective and subjective social status on obesity in a biracial cohort of adolescents

OBJECTIVE

To characterize the associations between socioeconomic status (SES), two levels of subjective social status (SSS), and adolescent obesity.

RESEARCH METHODS AND PROCEDURES

Cross-sectional study of 1491 black and white adolescents attending public school in a suburban school district in Greater Cincinnati, Ohio. BMI > or =95th percentile derived from measured height and weight defined overweight. Students rated SSS on separate 10-point scales for society and school. A parent provided information on parent education and household income for SES.

RESULTS

Although there were no sex differences in SES, black students were more likely to come from families with less well-educated parents and lower incomes (p < 0.001). Black girls had the lowest societal SSS (p = 0.003), lowest school SSS (p = 0.046), and highest BMI (p < 0.001). Prevalence of overweight was highest among black girls (26.0%) and boys (26.2%), intermediate for white boys (17.2%), and least for white girls (11.6%). Logistic regression modeling revealed that parent education, household income, and school SSS were each associated with overweight. In a fully adjusted model, school SSS retained its association to overweight (odds ratio, 1.16; 95% CI, 1.06,1.26) independent of SES. The association of school SSS was strongest among white girls, intermediate for white and black boys, and absent for black girls.

DISCUSSION

Perceptions of social stratification are independently associated with overweight. There were important racial and sex differences in the social status-overweight association. SSS in the more immediate, local reference group, the school, had the strongest association to overweight.

Obesity and cardiovascular risk

In most industrialized countries, 40-60% of the population is now overweight or obese. Obesity has recently been recognized as a major modifiable risk factor for cardiovascular disease, second only to cigarette smoking. Excess weight and obesity markedly increase the risk for hypertension, diabetes, coronary artery disease and congestive heart failure in both men and women. Populations most severely affected include the poor, the uneducated and certain racial and ethnic groups. Obesity is currently classified based on body mass index (BMI), but measurement of waist circumference as an important determinant of cardiovascular and metabolic risk is receiving increasing acceptance. For moderate overweight and obesity, interventions include dietary modification, increasing physical activity, behavior therapy and pharmacotherapy. Surgery is currently the only viable approach to morbid obesity.

Cardiovascular pharmacogenetics in the SNP era

In the past pharmacological agents have contributed to a significant reduction in age-adjusted incidence of cardiovascular events. However, not all patients treated with these agents respond favorably, and some individuals may develop side-effects. With aging of the population and the growing prevalence of cardiovascular risk factors worldwide, it is expected that the demand for cardiovascular drugs will increase in the future. Accordingly, there is a growing need to identify the 'good' responders as well as the persons at risk for developing adverse events. Evidence is accumulating to indicate that responses to drugs are at least partly under genetic control. As such, pharmacogenetics - the study of variability in drug responses attributed to hereditary factors in different populations - may significantly assist in providing answers toward meeting this challenge. Pharmacogenetics mostly relies on associations between a specific genetic marker like single nucleotide polymorphisms (SNPs), either alone or arranged in a specific linear order on a certain chromosomal region (haplotypes), and a particular response to drugs. Numerous associations have been reported between selected genotypes and specific responses to cardiovascular drugs. Recently, for instance, associations have been reported between specific alleles of the apoE gene and the lipid-lowering response to statins, or the lipid-elevating effect of isotretinoin. Thus far, these types of studies have been mostly limited to a priori selected candidate genes due to restricted genotyping and analytical capacities. Thanks to the large number of SNPs now available in the public domain through the SNP Consortium and the newly developed technologies (high throughput genotyping, bioinformatics software), it is now possible to interrogate more than 200,000 SNPs distributed over the entire human genome. One pharmacogenetic study using this approach has been launched by GlaxoSmithKline to identify the approximately 4% of patients who are predisposed to developing a hypersensitivity reaction to abacavir, an anti-HIV agent. Data collected thus far on the HLA locus on chromosome 6 indicate that this approach is feasible. Extended linkage disequilibrium can be detected readily, even across several haplotype blocks, thus potentially reducing the number of SNPs for future whole-genome scans. Finally, a modest number of cases and controls appears to be sufficient to detect genetic associations. There is little doubt that this type of approach will have an impact on the way cardiovascular drugs will be developed and prescribed in the future.

Secular trends in leisure-time physical activity in men and women across four decades

BACKGROUND

We examined secular trends in leisure-time physical activities (LTPA) in health-conscious men (n = 1359) from 1958 to 1998 and in women (n = 839) from 1978 to 1998, who were participants of the Baltimore Longitudinal Study of Aging (BLSA).

METHODS

LTPA was the self-reported time spent performing 97 activities, and was converted to metabolic equivalent of oxygen uptake (MET) minutes per day. Evaluations of LTPA were averaged for each decade. The prevalence of a sedentary lifestyle in each decade was assessed based on compliance with widely publicized recommendations for participation in physical activity. All analyses were adjusted for age, education, and race differences across decades.

RESULTS

Median high-intensity LTPA, defined as activities >/=6 METs, increased from 30 to 80 MET min/day from the 1960s to the 1990s for men (P < 0.01) but did not change between the 1970s and the 1990s in women. Moderate-intensity LTPA, defined as 4-5.9 METs, did not change significantly over these periods in either sex. The percentage of sedentary men, defined as those performing <40 MET min/day of high-intensity LTPA, declined across the four decades, whereas for women it did not change significantly.

CONCLUSIONS

In a health-conscious sample across a broad age range, national recommendations appear to have made modest progress in decreasing the proportion of sedentary adults.

Nonalcoholic Fatty liver disease

Nonalcoholic fatty liver disease is a condition gaining increasing recognition as a cause of cirrhosis and end-stage liver disease. The condition appears identical to alcoholic liver disease histologically, yet occurs in patients with negligible alcohol intake. Nonalcoholic fatty liver disease covers a spectrum of diseases ranging from simple fatty deposition in the liver to fat and inflammation and finally to fibrosis and cirrhosis. Conditions most frequently found in association with nonalcoholic fatty liver disease include obesity, Type 2 diabetes, and hyperlipidemia. Although the exact etiology of nonalcoholic fatty liver disease is not clear, insulin resistance is thought to play an important factor. Patients typically present with asymptomatic serum aminotransferase elevations of 2-3 times normal. Symptoms may include fatigue and abdominal pain. The clinical course is difficult to predict due to a lack of research in the natural history of the disease. It is known a percentage of patients progress to end-stage liver disease and may require liver transplantation. No medical treatment has been found to be totally effective. Patients who are overweight or obese should be encouraged in gradual weight reduction that has been associated with improvement in liver test abnormalities.

Adiponectin expression from human adipose tissue: relation to obesity, insulin resistance, and tumor necrosis factor-alpha expression

Adiponectin is a 29-kDa adipocyte protein that has been linked to the insulin resistance of obesity and lipodystrophy. To better understand the regulation of adiponectin expression, we measured plasma adiponectin and adipose tissue adiponectin mRNA levels in nondiabetic subjects with varying degrees of obesity and insulin resistance. Plasma adiponectin and adiponectin mRNA levels were highly correlated with each other (r = 0.80, P < 0.001), and obese subjects expressed significantly lower levels of adiponectin. However, a significant sex difference in adiponectin expression was observed, especially in relatively lean subjects. When men and women with a BMI <30 kg/m(2) were compared, women had a twofold higher percent body fat, yet their plasma adiponectin levels were 65% higher (8.6 +/- 1.1 and 14.2 +/- 1.6 micro g/ml in men and women, respectively; P < 0.02). Plasma adiponectin had a strong association with insulin sensitivity index (S(I)) (r = 0.67, P < 0.0001, n = 51) that was not affected by sex, but no relation with insulin secretion. To separate the effects of obesity (BMI) from S(I), subjects who were discordant for S(I) were matched for BMI, age, and sex. Using this approach, insulin-sensitive subjects demonstrated a twofold higher plasma level of adiponectin (5.6 +/- 0.6 and 11.2 +/- 1.1 micro g/ml in insulin-resistant and insulin-sensitive subjects, respectively; P < 0.0005). Adiponectin expression was not related to plasma levels of leptin or interleukin-6. However, there was a significant inverse correlation between plasma adiponectin and tumor necrosis factor (TNF)-alpha mRNA expression (r = -0.47, P < 0.005), and subjects with the highest levels of adiponectin mRNA expression secreted the lowest levels of TNF-alpha from their adipose tissue in vitro. Thus, adiponectin expression from adipose tissue is higher in lean subjects and women, and is associated with higher degrees of insulin sensitivity and lower TNF-alpha expression.

Gallbladder motility in agouti-yellow and leptin-resistant obese mice

BACKGROUND

Obesity is a polygenic disorder that is associated with gallstone disease. We have previously shown that leptin deficiency in obese mice correlates with decreased gallbladder motility, suggesting that leptin plays a role in the link between gallstone disease and obesity. However, most obese humans are leptin-resistant, and relatively few are leptin-deficient. To confirm that leptin dysfunction is responsible for impaired gallbladder motility in obese mice, we hypothesized that leptin-resistant obese mice (Lep(db)) would have abnormal gallbladder motility while obese mice with intact leptin function (Agouti Yellow, A(y)) would have normal gallbladder motility.

MATERIALS AND METHODS

Eighteen lean control (C57BL/6J), 10 A(y) and 12 Lep(db) female mice were fasted overnight, weighed, and livers and gallbladders were harvested. Liver weights and gallbladder volumes were measured. Gallbladder contractile responses (N/cm(2)) to acetylcholine (10(-5)M), neuropeptide Y (10(-8,-7,-6) M) and cholecystokinin (10(-10,-9,-8,-7)M) were determined in muscle bath chambers. Results were analyzed by analysis of various (ANOVA) and with the Mann-Whitney Rank Sum Test.

RESULTS

Both Agouti yellow (A(y)) and leptin-resistant (Lep(db)) obese mice had body weights, liver weights and gallbladder volumes that were significantly greater (P < 0.01) than lean control mice. Leptin-resistant obese mice had gallbladder responses to acetylcholine, neuropeptide Y and cholecystokinin that were significantly less (P < 0.01) than both lean control and Agouti yellow obese mice.

CONCLUSIONS

These data suggest that (1). leptin-resistant obese mice (Lep(db)) have abnormal gallbladder motility and (2). obese mice with normal leptin metabolism (A(y)) have normal gallbladder response to neurotransmitters. We conclude that leptin represents a link between obesity, gallbladder motility and gallstone formation.

Characteristics of patients with type 2 diabetes in México: Results from a large population-based nationwide survey

OBJECTIVE

To describe the clinical characteristics of the diabetic population that formed part of a population-based survey conducted in México.

RESEARCH DESIGN AND METHODS

In 2000, information was obtained from 42,886 subjects aged > or =20 years using a multistage sampling procedure. Standardized questionnaires were used. Anthropometric measurements, blood pressure, and capillary glucose concentrations were taken.

RESULTS

Type 2 diabetes was found in 3,597 subjects (age-adjusted prevalence 8.18%), of which 2,878 (80%) had previously been diagnosed. The average age of the diabetic participants was 55.2 +/- 13.5 years; 13% were <40 years of age. Nine percent had been diagnosed for >10 years. The average BMI was 29.2 +/- 5.7 kg/m(2); three-quarters of the cases had BMI >25 kg/m(2). The average waist circumference was 102 +/- 13.4 cm, and increased waist circumference was more common among women. Arterial hypertension was found in half of the cases and, of those on treatment, only one-third had a blood pressure <140/90 mmHg. Smoking was reported in 34% of the diabetic group, a higher rate than in the nondiabetic subjects. There was at least one modifiable coronary risk factor in 67.6% of the cases. Very few followed an exercise or dietary regimen and a small percentage used insulin.

CONCLUSIONS

Diabetes affects a large proportion of Mexican adults (8.18%). This figure may be underestimated. The majority of the subjects had modifiable risk factors for the chronic complications of diabetes. Only a few achieved adequate blood pressure control and other treatment goals.

Improving the nutritional resource environment for healthy living through community-based participatory research

OBJECTIVES

To build health promotion capacity among community residents through a community-based participatory model, and to apply this model to study the nutritional environment of an urban area to better understand the role of such resources in residents' efforts to live a healthy life.

DESIGN

A multiphase collaborative study that inventoried selected markets in targeted areas of high African-American concentration in comparison with markets in a contrasting wealthier area with fewer African Americans.

SETTING

A community study set in the Los Angeles metropolitan area.

PARTICIPANTS

African-American community organizations and community residents in the target areas.

INTERVENTIONS

Two surveys of market inventories were conducted. The first was a single-sheet form profiling store conditions and the availability of a small selection of healthy foods. The second provided detailed information on whether the store offered fruit, vegetables, low-fat dairy products, dried goods and other items necessary for residents to consume a nutritious diet.

RESULTS

The targeted areas were significantly less likely to have important items for living a healthier life. The variety and quality of fresh fruit and vegetable produce was significantly lower in the target areas. Such products as 1% milk, skim milk, low-fat and nonfat cheese, soy milk, tofu, whole grain pasta and breads, and low-fat meat and poultry items were significantly less available.

CONCLUSIONS

Healthy food products were significantly less available in the target areas. The authors conclude from these results that the health disparities experienced by African-American communities have origins that extend beyond the health delivery system and individual behaviors inasmuch as adherence to the healthy lifestyle associated with low chronic disease risk is more difficult in resource-poor neighborhoods than in resource-rich ones.

Idiopathic intracranial hypertension: associations with coagulation disorders and polycystic-ovary syndrome

To better understand potentially reversible causes of idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, and an apparent association of IIH with polycystic-ovary syndrome (PCOS), we assessed associations of IIH with coagulation disorders and with PCOS in 38 women with well-documented IIH. Fifteen women were found to have PCOS; 14 of them were obese, with a body-mass index (BMI) greater than 30 kg/m(2), and 10 were extremely obese (BMI > or = 40). Factor VIII concentration was high (>150%) in 9 of 38 (24%) IIH cases, compared with 0 of 40 healthy adults controls (P(f) =.0009). Familial aggregation of high concentrations of factor VIII, associated with thrombophilia, was documented in all 5 of the 9 high-level factor VIII probands' families who were sampled. Activated partial thromboplastin time (APTT) was prolonged (> or =31.5 seconds) in 10 of 38 (26%) IIH cases, compared with 1 of 32 (3%) controls (P(f) =.009) and, in 4 of these cases, was accompanied by the lupus anticoagulant. Plasminogen activator inhibitor activity (PAI-Fx) was high (>21.1 U/mL) in 9 of 38 cases (24%), compared with 1 of 40 controls (3%) (P(f) =.006). Lipoprotein A was high (> or =35 mg/dL) in 13 of 37 cases (35%), compared with 5 of 40 controls (13%) (P(f) =.03). IIH cases did not differ (P >.05) from controls for homocysteine, proteins C and S, free S, antithrombin III, ACLAs IgG and IgM, dilute Russell's viper venom time, Factor XI, factor V Leiden G1691A, G20210A prothrombin, C677T MTHFR, plasminogen activator inhibitor 4G/5G, or platelet glycoprotein PL A1A2 mutations. Exogenous estrogens (n = 23), clomiphene (n = 1), or pregnancy (n = 4) accompanied the first appearance of IIH in 28 women. PCOS and coagulation disorders, often augmented by exogenous estrogens or pregnancy, are associated with IIH.

Long-term changes in energy expenditure and body composition after massive weight loss induced by gastric bypass surgery

BACKGROUND

Little is known about the determinants of individual variability in body weight and fat loss after gastric bypass surgery or about the effects of massive weight loss induced by this surgery on energy requirements.

OBJECTIVES

The objectives were to determine changes in energy expenditure and body composition with weight loss induced by gastric bypass surgery and to identify presurgery predictors of weight loss.

DESIGN

Thirty extremely obese women and men with a mean (+/- SD) age of 39.0 +/- 9.6 y and a body mass index (BMI; in kg/m(2)) of 50.1 +/- 9.3 were tested longitudinally under weight-stable conditions before surgery and after weight loss and stabilization (14 +/- 2 mo). Total energy expenditure (TEE), resting energy expenditure (REE), body composition, and fasting leptin were measured.

RESULTS

Subjects lost 53.2 +/- 22.2 kg body weight and had significant decreases in REE (-2.4 +/- 1.0 MJ/d; P < 0.001) and TEE (-3.6 +/- 2.5 MJ/d; P < 0.001). Changes in REE were predicted by changes in fat-free mass and fat mass. The average physical activity level (TEE/REE) was 1.61 at both baseline and follow-up (P = 0.98). Weight loss was predicted by baseline fat mass and BMI but not by any energy expenditure variable or leptin. Measured REE at follow-up was not significantly different from predicted REE.

CONCLUSIONS

TEE and REE decreased by 25% on average after massive weight loss induced by gastric bypass surgery. REE changes were predicted by loss of body tissue; thus, there was no significant long-term change in energy efficiency that would independently promote weight regain.

Impact of obesity in the setting of high-dose chemotherapy

Obesity is a common and increasing problem affecting the developed world. Chemotherapy pharmacokinetics in the context of obesity demonstrate prolonged elimination time for several agents, but there is no consensus regarding optimal dosing schemes. Retrospective studies suggest differences in toxicity for obese adult patients but these data may be greatly impacted by chemotherapy dose adjustments. Outcome data from several studies have suggested that obese adult patients suffer poorer disease-free survival and overall survival, although this is not a uniform conclusion in all studies. Prospective studies of chemotherapy pharmacokinetics are needed to address the issue of optimal chemotherapy dosing in the obese population.

Correlates of overweight and obesity among lesbian and bisexual women

BACKGROUND

Recent studies find lesbians at greater risk for overweight and obesity than heterosexual women. While this may reflect differences in attitudes concerning weight and body shape, little is actually known about risk factors within this group. This study examines correlates of obesity and exercise frequency among lesbians and bisexual women.

METHODS

Data from a snowball sample (n = 1209) of lesbians/bisexual women living in Los Angeles Country were utilized. Overweight was defined as BMI >/= 25 kg/m(2); obesity as BMI >/= 30. Associations between sociodemographic characteristics, exercise frequency, health indicators, and weight-related measures were evaluated to identify independent predictors of BMI and exercise frequency.

RESULTS

Prevalence of overweight and obesity among lesbians varied by racial/ethnic background. Higher BMI was associated with older age, poorer health status, lower educational attainment, relationship cohabitation, and lower exercise frequency. Higher BMI, perceptions of being overweight, and reporting a limiting health condition were identified as independent predictors of infrequent exercise. Women were generally quite accurate in self-perceptions of weight status.

CONCLUSIONS

Correlates of overweight and obesity among lesbians and bisexual women are generally comparable to those observed in studies of heterosexual women. Evidence that lesbians' higher BMI is associated with higher levels of fitness is not supported.

Prevalence of overweight, obesity, and associated diseases among outpatients in a public hospital

BACKGROUND

The prevalence of obesity is increasing and may be particularly high among indigent public hospital patients. The purpose of this study was to determine the prevalence of obesity and its associated chronic medical conditions among outpatients at Louisiana State University Health Sciences Center-Shreveport, an urban tertiary health center that serves a mostly black, indigent population.

METHODS

A cross-sectional survey was conducted on 1,507 primary care patients. Age, sex, weight, height, and diagnoses were recorded, and body mass index (BMI) was calculated.

RESULTS

Eighty-one percent of patients were overweight or obese and 75% had one or more obesity-associated conditions. Higher BMI was significantly associated with increased prevalence of obesity-related diseases (P < 0.001) even when adjusted for age and sex.

CONCLUSION

Overweight and obesity rates at this public hospital are alarming and may indicate a problem in public hospitals across the United States. The process and structure of care for overweight and obese patients need to be evaluated, and training for residents needs to address this problem.

The changing face of esophageal malignancy

Concern has been expressed about the rapid increase in the incidence of esophageal carcinoma in the United States. This rise is due to an increase in the number of cases of adenocarcinoma of the esophagus. Because of the relatively small number of cases of esophageal carcinoma, the absolute risk of developing this cancer in the United States remains small. Potential origins for this increase in esophageal adenocarcinoma are examined in this review, including the risk induced by obesity, low dietary antioxidants, high dietary fat, family history of breast cancer, smoking, gastroesophageal reflux, and Barrett's esophagus. The risk of esophageal adenocarcinoma is inversely associated with infection by Helicobacter pylori organisms. A better understanding of risk factors involved in the increased incidence of esophageal adenocarcinoma is important for development of new preventive strategies for this serious disorder.

Rapid increase in the use of oral antidiabetic drugs in the United States, 1990-2001

OBJECTIVE

To describe the use of oral antidiabetic drugs for management of type 2 diabetes in the U.S. from 1990 through 2001.

RESEARCH DESIGN AND METHODS

Data on oral antidiabetic drugs were derived from two pharmaceutical marketing databases from IMS Health, the National Prescription Audit Plus and the National Disease and Therapeutic Index.

RESULTS

In 1990, 23.4 million outpatient prescriptions of oral antidiabetic agents were dispensed. By 2001, this number had increased 3.9-fold, to 91.8 million prescriptions. Glipizide and glyburide, two sulfonylurea medications, accounted for approximately 77% of prescriptions of oral antidiabetic drugs in 1990 and 35.5% of prescriptions in 2001. By 2001, the biguanide metformin (approved in 1995) had captured approximately 33% of prescriptions, and the thiazolidinedione insulin sensitizers (rosiglitazone and pioglitazone marketed beginning in 1999) accounted for approximately 17% of market share. Compared with patients treated in 1990, those in 2001 were proportionately younger and they more often used oral antidiabetic drugs and insulin in combination. Internists and general and family practitioners were the primary prescribers of this class of drugs.

CONCLUSIONS

Consistent with the reported increase in the prevalence of type 2 diabetes, the number of dispensed outpatient prescriptions of oral antidiabetic drugs increased rapidly between 1990 and 2001. This period was marked by an increase in the treatment of younger people and the use of oral antidiabetic drugs in combination. With the approval in the last decade of several new types of oral antidiabetic medications with different mechanisms of action, options for management of type 2 diabetes have expanded.

A 6-month randomized, placebo-controlled, dose-ranging trial of topiramate for weight loss in obesity

OBJECTIVE

To evaluate the efficacy and safety of topiramate (TPM) for weight loss in healthy obese subjects.

RESEARCH METHODS AND PROCEDURES

A randomized, double-blind, placebo-controlled, dose-ranging trial was conducted. Three hundred eighty-five subjects, 18 and 75 years of age, were randomized to receive either placebo or TPM at 64, 96, 192, or 384 mg daily. Dosing began at 16 mg once daily. In week 2, the dose was increased to 16 mg twice daily. Thereafter, the dose was raised every week by 32 mg/d (16 mg twice daily) until subjects reached their target dose. Twenty-four weeks after beginning treatment, all subjects were tapered off treatment by a dose reduction of 50% per week. All participants received the same lifestyle program.

RESULTS

Mean percent weight loss from baseline to week 24 was -2.6% in placebo-treated patients vs. -5.0%, -4.8%, -6.3%, and -6.3% in the 64, 96, 192, and 384 mg/d TPM groups, respectively. Greater percentages of TPM-treated patients lost at least 5% or 10% of body weight compared with placebo. The most frequent adverse events were related to the central or peripheral nervous system, including paresthesia, somnolence, and difficulty with memory, concentration, and attention. Most events were dose-related, occurred early in treatment, and usually resolved spontaneously; only 21% receiving TPM withdrew due to adverse events compared with 11% on placebo.

DISCUSSION

TPM produced significantly greater weight loss than placebo at all doses.

Ontogeny of the hypothalamic neuropeptide Y system

Early onset obesity and type II diabetes is rapidly becoming an epidemic, especially within the United States. This dramatic increase is likely due to many factors including both prenatal and postnatal environmental cues. The purpose of this review is to highlight some of the recent advances in our knowledge of the development of the hypothalamic circuits involved in the regulation of energy balance, with a focus on the neuropeptide Y (NPY) system. Unlike the adult rat, during the postnatal period NPY is transiently expressed in several hypothalamic regions, along with the expected expression within the arcuate nucleus (ARH). These transient populations of NPY neurons during the postnatal period may provide local NPY production to sustain the necessary energy intake during this critical growth phase. This may be physiologically important since ARH-NPY projections do not fully develop until the 3rd postnatal week. The significance of this ontogeny is that many peripheral metabolic signals have little effect of feeding prior to the development of the ARH projections. The essential questions now are whether prenatal and/or postnatal exposure to high levels of insulin or leptin during development can cause permanent changes in the function of hypothalamic circuits. It is vital to understand not only the natural development of the hypothalamic circuits that regulate energy homeostasis, but also their abnormal development caused by maternal and postnatal environmental cues. This will be pivotal for designing intervention and therapeutics to treat early onset obesity/type II diabetes, which may very well need to be different from those designed to prevent/treat adult onset obesity/type II diabetes.

Managing cardiovascular risk reduction in elderly adults. By promoting and monitoring healthy lifestyle changes, health care providers can help older adults improve their cardiovascular health

Primary care practitioners must explore the most effective techniques for promoting cardiovascular risk reduction in older adults. Managing lifestyle modification risk factors, such as smoking cessation, obesity, sedentary lifestyle, and nutrition is discussed in this article. Other risk factor modification efforts, often not highlighted, include managing homocysteinemia, and sedentary behavior. These factors are presented as equally important modifiable coronary heart disease risks.

Insulin resistance and the sympathetic nervous system

The obesity epidemic is driving metabolic (insulin resistance) syndrome-related health problems including an approximately threefold increased coronary heart disease risk. Sympathetic hyperfunction may participate in the pathogenesis and complications of the metabolic syndrome including higher blood pressure, a more active renin-angiotensin system, insulin resistance, faster heart rates, and excess cardiovascular disease including sudden death. Possible factors augmenting sympathetic activation in the metabolic syndrome include alterations of insulin, leptin, nonesterified fatty acids (NEFAs), cytokines, tri-iodothyronine, eicosanoids, sleep apnea, nitric oxide, endorphins, and neuropeptide Y. Of note, high plasma NEFAs are a risk factor for hypertension and sudden death. In short-term human studies, NEFAs can raise blood pressure, heart rate, and a(1)-adrenoceptor vasoreactivity, while reducing baroreflex sensitivity, endothelium-dependent vasodilatation, and vascular compliance. Efforts to further identify the mechanisms and consequences of sympathetic dysfunction in the metabolic syndrome may provide insights for therapeutic advances to ameliorate the excess cardiovascular risk and adverse outcomes.

Update on pediatric nutrition: breastfeeding, infant nutrition, and growth

Recent studies continue to point out the critical nature of a patient's nutritional status in helping to determine important health outcomes in pediatrics. We review recent data concerning the composition of breast milk and its adequacy to support infant growth in the first six months of life, as well as trials that support breastfeeding as an important method to delay or reduce the incidence of atopic diseases such as eczema, allergies, and asthma. Studies have also been published that show how physician education and training about breastfeeding can be optimized. Studies showing how nutritional status is measured (using standard anthropometric techniques as well as more modern measures of basal metabolic rate) are highlighted, as well as the role of micronutrient supplementation of patients with the human immunodeficiency virus infection and diarrheal diseases.

Anaphylactic reaction to a dietary supplement containing willow bark

OBJECTIVE

To report a case of anaphylaxis resulting from the use of a willow bark-containing dietary supplement in a patient with a history of an aspirin allergy.

CASE SUMMARY

A 25-year-old white woman presented to the emergency department of a community teaching hospital with anaphylaxis requiring epinephrine, diphenhydramine, methylprednisolone, and volume resuscitation to which she responded favorably. Medication history revealed that she had ingested 2 capsules of Stacker 2 (NVE Pharmaceuticals, Newton, NJ), a dietary supplement promoted for weight loss, prior to experiencing her initial symptoms. Among other active ingredients, this product contains willow bark. Of significance is that this patient also reported a history of allergy to acetylsalicylic acid. No other causes for anaphylaxis were identified. She continued to receive routine supportive care and the remaining hospital course was uncomplicated.

DISCUSSION

Dietary supplements, including herbal products, are used by many individuals who consider them to be inherently safe despite limited regulatory oversight by the Food and Drug Administration. While there may be value to specific botanical ingredients, a potential for adverse effects also exists. The popular product consumed by our patient is used for weight loss and contains willow bark, a source of salicylates. Based on the Naranjo probability scale, it is probable that this case of anaphylaxis was due to this dietary supplement.

CONCLUSIONS

The use of any willow bark-containing dietary supplement may present a risk of anaphylactic reaction to patients with a history of allergy to salicylates. Clinicians need to recognize the potential for adverse effects from dietary supplements.

Dietary patterns and changes in body mass index and waist circumference in adults

BACKGROUND

Obesity has increased > 20% in the past decade in the United States, and more than one-half of US adults are overweight or obese.

OBJECTIVE

Our objective was to further elucidate the nutritional etiology of changes in body mass index (BMI; in kg/m(2)) and waist circumference by dietary intake pattern. We hypothesized that a healthy dietary pattern would lead to smaller changes in BMI and waist circumference than would other dietary patterns.

DESIGN

Subjects were 459 healthy men and women participating in the ongoing Baltimore Longitudinal Study of Aging. Diet was assessed with the use of 7-d dietary records, from which 41 food groups were created and entered into a cluster analysis.

RESULTS

Five dietary patterns were derived (healthy, white bread, alcohol, sweets, and meat and potatoes). The mean annual change in BMI was 0.30 +/- 0.06 for subjects in the meat-and-potatoes cluster and 0.05 +/- 0.06 for those in the healthy cluster (P < 0.01). The mean annual change in waist circumference was more than 3 times as great for subjects in the white-bread cluster (1.32 +/- 0.29 cm) as for those in the healthy cluster (0.43 +/- 0.27 cm) (P < 0.05).

CONCLUSIONS

Consuming a diet high in fruit, vegetables, reduced-fat dairy, and whole grains and low in red and processed meat, fast food, and soda was associated with smaller gains in BMI and waist circumference. Because foods are not consumed in isolation, dietary pattern research based on natural eating behavior may be useful in understanding dietary causes of obesity and in helping individuals trying to control their weight.

Body composition assessment in extreme obesity and after massive weight loss induced by gastric bypass surgery

Body composition methods were examined in 20 women [body mass index (BMI) 48.7 +/- 8.8 kg/m(2)] before and after weight loss [-44.8 +/- 14.6 (SD) kg] after gastric bypass (GBP) surgery. The reference method, a three-compartment (3C) model using body density by air displacement plethysmography and total body water (TBW) by H(2)18O dilution (3C-H(2)18O), showed a decrease in percent body fat (%BF) from 51.4 to 34.6%. Fat-free mass hydration was significantly higher than the reference value (0.738) in extreme obesity (0.756; P < 0.001) but not after weight reduction (0.747; P = 0.16). %BF by H(2)18O dilution and air displacement plethysmography differed significantly from %BF by 3C-H(2)18O in extreme obesity (P < 0.05) and 3C models using (2)H(2)O or bioelectrical impedance analysis (BIA) to determine TBW improved mean %BF estimates over most other methods at both time points. BIA results varied with the equation used, but BIA better predicted %BF than did BMI at both time points. All methods except BIA using the Segal equation were comparable to the reference method for determining changes over time. A simple 3C model utilizing air displacement plethysmography and BIA is useful for clinical evaluation in this population.

Nutritional issues for adolescents

This chapter provides background on the nutritional health of adolescents, focusing on a public health or population-level approach. We detail some specific nutritional issues and related health outcomes that are particularly relevant to adolescents, including overweight and obesity, type 2 diabetes, eating-related disorders and bone health as it relates to calcium intake. We discuss implications of the trends in adolescent dietary habits for practitioners and propose a research agenda for better understanding and positively influencing future adolescent nutritional health.

Eating behaviors and indexes of body composition in men and women from the Québec family study

OBJECTIVE

To put into relationship the dietary and anthropometric profile of men and women with their eating behaviors (cognitive dietary restraint, disinhibition, and susceptibility to hunger) and to assess whether gender and obesity status influence these associations.

RESEARCH METHODS AND PROCEDURES

Anthropometric measurements (including visceral adipose tissue accumulation), dietary profile (3-day food record), and eating behaviors (Three-Factor Eating Questionnaire) were determined in a sample of 244 men and 352 women.

RESULTS

Women had significantly higher cognitive dietary restraint and disinhibition scores than men (p < 0.0001). In both genders, scores for disinhibition and susceptibility to hunger, but not for cognitive dietary restraint, were higher in obese subjects than in overweight and nonobese subjects (p < 0.05). Positive correlations were observed between rigid restraint and most of the anthropometric variables studied (0.12 <or= r <or= 0.16). Moreover, in women, flexible restraint was negatively associated with body fat and waist circumference (r = -0.11). Cognitive dietary restraint and rigid restraint were positively related to BMI among nonobese women (0.19 <or= r <or= 0.20), whereas in obese men, cognitive dietary restraint and flexible restraint tended to be negatively correlated with BMI (-0.20 <or= r <or= -0.22; p = 0.10).

DISCUSSION

Gender could mediate associations observed between eating behaviors and anthropometric profile. It was also found that disinhibition and susceptibility to hunger are positively associated with the level of obesity. On the other hand, cognitive dietary restraint is not consistently related to body weight and adiposity, whereas rigid and flexible restraint are oppositely associated to obesity status, which suggests that it is important to differentiate the subscales of cognitive dietary restraint. Finally, counseling aimed at coping with disinhibition and susceptibility to hunger could be of benefit for the long-term treatment of obesity.

Rapid weight gain during infancy and obesity in young adulthood in a cohort of African Americans

BACKGROUND

Obesity is increasing in the United States. Evidence-based prevention is a public health priority and should target well-defined risk factors and critical periods.

OBJECTIVE

We tested the hypothesis that rapid weight gain during early infancy is associated with obesity in African American young adults, a group at increased risk of obesity.

DESIGN

A cohort of 300 African Americans born at full term was followed from birth to 20 y of age. A pattern of rapid weight gain was defined as an increase in weight-for-age > or = 1 SD between birth and 4 mo.

RESULTS

About 29% of subjects had a pattern of rapid weight gain during infancy; 8% were obese [body mass index (in kg/m(2)) > or = 30] at age 20 y. One-third of the obesity at age 20 y could be attributed to rapid weight gain in the first 4 mo of life. After adjustment for confounding factors, subjects with rapid weight gain during early infancy were more likely to become obese at age 20 y (odds ratio = 5.22; 95% CI: 1.55, 17.6; P = 0.008). The results were confirmed by using a combination of body mass index and skinfold thickness (odds ratio = 6.72; 95% CI: 1.93, 23.4; P = 0.003).

CONCLUSIONS

The results of the present study provide evidence that a pattern of rapid weight gain during early infancy is associated with obesity not only in childhood but also in young adulthood. We propose that early infancy constitutes a critical period for the development of obesity. Mechanisms of action and prevention strategies require further investigation.

Are physicians equipped to address the obesity epidemic? Knowledge and attitudes of internal medicine residents

BACKGROUND

To analyze whether internists are suited for their role in treating the growing numbers of obese patients, we surveyed residents about their knowledge and attitudes regarding obesity. Previous assessments have not analyzed familiarity with obesity measurement tools or the correlation between knowledge and attitudes.

METHODS

We administered a survey to 87 internal medicine residents in two urban, university-based residency programs.

RESULTS

Almost all respondents understood the medical consequences of obesity, but 60% did not know the minimum BMI for diagnosing obesity, 69% did not recognize waist circumference as a reasonable measure of obesity, and 39% incorrectly reported their own BMI. Although nearly all respondents agreed that treating obesity was important, only 30% reported treatment success. Forty-four percent felt qualified to treat obese patients, and 31% reported treatment to be futile. Knowledge and attitudes were not correlated. Rasch analysis of knowledge and attitude subscales showed satisfactory model fit and item reliability of at least 0.96.

CONCLUSIONS

Despite solid knowledge of the comorbid conditions associated with obesity, residents have a poor grasp of the tools necessary to identify obesity. They also have negative opinions about their skills for treating obese patients. Residency training not only must improve knowledge of obesity measurement tools but also must address physicians' negative attitudes toward obesity treatment.

The menopause and obesity

In summary, menopause tends to be associated with an increased risk of obesity and a shift to an abdominal fat distribution with associated increase in health risks. Changes in body composition at menopause may be caused by the decrease in circulating estrogen, and, for fat distribution shifts, the relative increase in the androgen-estrogen ratio is likely to be important. Clinicians need to be aware of the likelihood of weight gain during the perimenopausal and postmenopausal years because behavioral strategies for weight loss can be effectively used in this population. Weight loss or prevention of weight gain is likely to have significant health benefits for older women.

A randomized trial of a low-carbohydrate diet for obesity

BACKGROUND

Despite the popularity of the low-carbohydrate, high-protein, high-fat (Atkins) diet, no randomized, controlled trials have evaluated its efficacy.

METHODS

We conducted a one-year, multicenter, controlled trial involving 63 obese men and women who were randomly assigned to either a low-carbohydrate, high-protein, high-fat diet or a low-calorie, high-carbohydrate, low-fat (conventional) diet. Professional contact was minimal to replicate the approach used by most dieters.

RESULTS

Subjects on the low-carbohydrate diet had lost more weight than subjects on the conventional diet at 3 months (mean [+/-SD], -6.8+/-5.0 vs. -2.7+/-3.7 percent of body weight; P=0.001) and 6 months (-7.0+/-6.5 vs. -3.2+/-5.6 percent of body weight, P=0.02), but the difference at 12 months was not significant (-4.4+/-6.7 vs. -2.5+/-6.3 percent of body weight, P=0.26). After three months, no significant differences were found between the groups in total or low-density lipoprotein cholesterol concentrations. The increase in high-density lipoprotein cholesterol concentrations and the decrease in triglyceride concentrations were greater among subjects on the low-carbohydrate diet than among those on the conventional diet throughout most of the study. Both diets significantly decreased diastolic blood pressure and the insulin response to an oral glucose load.

CONCLUSIONS

The low-carbohydrate diet produced a greater weight loss (absolute difference, approximately 4 percent) than did the conventional diet for the first six months, but the differences were not significant at one year. The low-carbohydrate diet was associated with a greater improvement in some risk factors for coronary heart disease. Adherence was poor and attrition was high in both groups. Longer and larger studies are required to determine the long-term safety and efficacy of low-carbohydrate, high-protein, high-fat diets.

Diet-dependent obesity and hypercholesterolemia in the New Zealand obese mouse: identification of a quantitative trait locus for elevated serum cholesterol on the distal mouse chromosome 5

AIMS

New Zealand obese (NZO) mice exhibit a polygenic syndrome of obesity, insulin resistance, and hypercholesterolemia that resembles the human metabolic syndrome. This study was performed in order to locate genes responsible for elevated serum cholesterol and to compare their effects under a standard and high fat diet.

METHODS

A backcross population of NZO with SJL mice (NZO x F1(SJL x NZO)) was generated. Mice were raised on a normal or high fat diet and were monitored for 22 weeks (body weight, serum cholesterol, and blood glucose). A genome-wide scan was performed by genotyping of approximately 200 polymorphic microsatellite markers by PCR and linkage analysis was performed with the MAPMAKER program.

RESULTS

In the genome-wide scan, a single susceptibility locus for hypercholesterolemia (Chol1/NZO, maximum LOD score 14.5 in a combined population of 523 backcross mice) was identified on chromosome 5. Cholesterol levels were significantly elevated in both male and female homozygous carriers of the Chol1/NZO allele. The locus maps 40cM distal of the previously described obesity locus Nob1 in the vicinity of the marker D5Mit244 and in the vicinity of hypercholesterolemia QTL previously identified in the NZB, CAST, and C57BL/6J strains. Chol1/NZO was not associated with elevated body weight, serum insulin, or hyperglycemia. The high fat diet significantly increased serum cholesterol levels, but the fat content of the diet did not alter the absolute effect of Chol1/NZO.

CONCLUSIONS

Chol1/NZO is a major susceptibility locus on the distal mouse chromosome 5, which produces gender-independent hypercholesterolemia in NZO mice. The effect of Chol1/NZO was independent of the dietary fat content and was not associated with the other traits of the metabolic syndrome. Thus, it is suggested that the responsible gene might be involved in cholesterol metabolism.

Aerobic exercise and endurance: improving fitness for health benefits

Clinicians who understand how the body responds to exercise, how aerobic training improves cardiovascular fitness, and the benefits and principles of prescribing aerobic exercise can effectively encourage patients to become active and optimize programs for those already active. Patients who are active at an early age and who continue to enjoy active lifestyles as adults will attenuate the normal losses in cardiovascular endurance, strength, and flexibility that accompany aging and sedentary living, thereby maintaining greater independence throughout their life spans.

The relation of menarcheal age to obesity in childhood and adulthood: the Bogalusa heart study

BACKGROUND

Several studies have shown that girls who undergo menarche at a relatively young age tend to be more obese as adults. However, because childhood (pre-menarcheal) levels of weight and height are associated with an earlier menarche, the increased prevalence of adult obesity among early maturers may largely reflect the persistence of childhood obesity into adulthood.

METHODS

We examined these interrelationships among 1179 girls (65% white, 35% black) who were examined as children (mean age, 9 y), adolescents, and adults (mean age, 26 y) in the Bogalusa Heart Study.

RESULTS

Both white and black women who reported that they underwent menarche before age 12 y had, on average, higher adult levels of weight (+10 kg), body mass index (BMI, +4 kg/m2) and skinfold thicknesses (+6 mm) than did women who underwent menarche after age 13.5 y. However, relatively fat children tended to undergo menarche earlier than did thinner children, with each standard deviation increase in pre-menarcheal BMI increasing the odds of early menarche (<12 y) by approximately 2-fold. Stratified and regression analyses indicated that (1) adult obesity was more strongly associated with childhood obesity than with menarcheal age, and (2) about 60% to 75% of the apparent effect of menarcheal age was due to the influence of childhood obesity on both menarcheal age and adult obesity.

CONCLUSIONS

Although additional longitudinal studies are needed, it is likely that the importance of early menarche in adult obesity has been overestimated. Most of apparent influence of menarcheal age on adult obesity is attributable to the association of childhood obesity with both menarcheal age and adult obesity.

Fetal origins of obesity

The worldwide epidemic of obesity continues unabated. Obesity is notoriously difficult to treat, and, thus, prevention is critical. A new paradigm for prevention, which evolved from the notion that environmental factors in utero may influence lifelong health, has emerged in recent years. A large number of epidemiological studies have demonstrated a direct relationship between birth weight and BMI attained in later life. Although the data are limited by lack of information on potential confounders, these associations seem robust. Possible mechanisms include lasting changes in proportions of fat and lean body mass, central nervous system appetite control, and pancreatic structure and function. Additionally, lower birth weight seems to be associated with later risk for central obesity, which also confers increased cardiovascular risk. This association may be mediated through changes in the hypothalamic pituitary axis, insulin secretion and sensing, and vascular responsiveness. The combination of lower birth weight and higher attained BMI is most strongly associated with later disease risk. We are faced with the seeming paradox of increased adiposity at both ends of the birth weight spectrum-higher BMI with higher birth weight and increased central obesity with lower birth weight. Future research on molecular genetics, intrauterine growth, growth trajectories after birth, and relationships of fat and lean mass will elucidate relationships between early life experiences and later body proportions. Prevention of obesity starting in childhood is critical and can have lifelong, perhaps multigenerational, impact.

Exercise considerations for the sedentary, overweight adult

The significant rise in the prevalence of overweight and obesity has increased the importance of addressing this significant public health problem. Exercise appears to be an important factor for addressing the obesity epidemic. This review will focus on the role of exercise in the management of body weight and factors that should be considered when prescribing exercise to overweight adults.

Chromium picolinate for reducing body weight: meta-analysis of randomized trials

The aim of this meta-analysis was to assess the evidence of chromium picolinate for reducing body weight. Literature searches were conducted on Medline, Embase, The Cochrane Library, Amed and Ciscom. Nine experts and four manufacturers of commercial preparations containing chromium picolinate were asked to contribute published and unpublished studies. There were no restrictions regarding the language of publication. The screening of studies, selection, data extraction, validation and the assessment of methodological quality were performed independently by two reviewers. To be included, studies were required to state that they were randomized, double-blind and placebo-controlled, and report on body weight. Ten trials met all inclusion criteria and provided data, which were suitable for statistical pooling. For body weight a significant differential effect was found in favour of chromium picolinate (weighted mean difference: -1.1 kg; 95% confidence interval (CI): -1.8 to -0.4 kg, n=489). Sensitivity analysis suggests that this effect is largely dependent on the results of a single trial (weighted mean difference: -0.9 kg; 95% CI: -2.0 to 0.2 kg, n=335). Three of the reviewed trials reported on adverse events, indicating their absence in the treatment groups. In conclusion, our meta-analysis suggests a relatively small effect of chromium picolinate compared with placebo for reducing body weight. The clinical relevance of the effect is debatable and the lack of robustness means that the result has to be interpreted with caution.

Skeletal muscle lipid metabolism with obesity

The objectives of this study were to 1). examine skeletal muscle fatty acid oxidation in individuals with varying degrees of adiposity and 2). determine the relationship between skeletal muscle fatty acid oxidation and the accumulation of long-chain fatty acyl-CoAs. Muscle was obtained from normal-weight [n = 8; body mass index (BMI) 23.8 +/- 0.58 kg/m(2)], overweight/obese (n = 8; BMI 30.2 +/- 0.81 kg/m(2)), and extremely obese (n = 8; BMI 53.8 +/- 3.5 kg/m(2)) females undergoing abdominal surgery. Skeletal muscle fatty acid oxidation was assessed in intact muscle strips. Long-chain fatty acyl-CoA concentrations were measured in a separate portion of the same muscle tissue in which fatty acid oxidation was determined. Palmitate oxidation was 58 and 83% lower in skeletal muscle from extremely obese (44.9 +/- 5.2 nmol x g(-1) x h(-1)) patients compared with normal-weight (71.0 +/- 5.0 nmol x g(-1) x h(-1)) and overweight/obese (82.2 +/- 8.7 nmol x g(-1) x h(-1)) patients, respectively. Palmitate oxidation was negatively (R = -0.44, P = 0.003) associated with BMI. Long-chain fatty acyl-CoA content was higher in both the overweight/obese and extremely obese patients compared with normal-weight patients, despite significantly lower fatty acid oxidation only in the extremely obese. No associations were observed between long-chain fatty acyl-CoA content and palmitate oxidation. These data suggest that there is a defect in skeletal muscle fatty acid oxidation with extreme obesity but not overweight/obesity and that the accumulation of intramyocellular long-chain fatty acyl-CoAs is not solely a result of reduced fatty acid oxidation.

Overview of obesity

The purpose of this article is to provide a succinct overview of obesity. It will be useful to highlight some of the epidemiological issues associated with this disease. Obesity is intertwined between public health issues, increased risk of morbidity and mortality, rising health care costs and expensive treatment options, social stigma, and internal psychological challenges--clearly no easy answers as to how to treat this health dilemma. Even with all of the challenges, bariatric surgery certainly offers a viable option for patients to get their health back, and more important, their lives back.

Rhythmic, reciprocal ghrelin and leptin signaling: new insight in the development of obesity

The hypothalamus integrates metabolic, neural and hormonal signals to evoke an intermittent appetitive drive in the daily management of energy homeostasis. Three major players identified recently in the feedback communication between the periphery and hypothalamus are leptin, ghrelin and neuropeptide Y (NPY). We propose that reciprocal circadian and ultradian rhythmicities in the afferent humoral signals, anorexigenic leptin from adipocytes and orexigenic ghrelin from stomach, encode a corresponding discharge pattern in the appetite-stimulating neuropeptide Y network in the hypothalamus. An exquisitely intricate temporal relationship among these signaling modalities with varied sites of origin is paramount in sustenance of weight control on a daily basis. Our model envisages that subtle and progressive derangements in temporal communication, imposed by environmental shifts in energy intake, impel a positive energy balance culminating in excessive weight gain and obesity. This conceptual advance provides a new target for designing pharmacologic or gene transfer therapies that would normalize the rhythmic patterns of afferent hormonal and efferent neurochemical messages.

Obesity-associated hypertension and kidney disease

PURPOSE OF REVIEW

The worldwide prevalence of obesity and its associated metabolic and cardiovascular disorders has risen dramatically during the past two decades. Our objective is to review the mechanisms that link obesity with hypertension and altered kidney function.

RECENT FINDINGS

Current evidence suggests that excess weight gain may be responsible for 65-75% of the risk for essential hypertension. Abnormal renal pressure natriuresis, due initially to increased renal tubular sodium reabsorption, is a key factor linking obesity with hypertension. Obesity increases renal sodium reabsorption by activating the renin-angiotensin and sympathetic nervous systems, and by altering intrarenal physical forces. Adipose tissue functions as an endocrine organ, secreting hormones/cytokines (e.g. leptin) that may activate the sympathetic nervous system and alter kidney function. Excess visceral adipose tissue may physically compress the kidneys, increasing intrarenal pressures and tubular reabsorption. Sustained obesity eventually causes structural changes in the kidneys and loss of nephron function, further increasing arterial pressure and leading to severe renal disease in some cases.

SUMMARY

Despite considerable progress in understanding the pathophysiology of obesity, there are still no specific guidelines for the treatment of obesity hypertension other than weight reduction. Special considerations for obese hypertensive patients, in addition to controlling blood pressure, are correcting the metabolic abnormalities and protecting the kidneys from injury. This remains an important area for further research, especially in view of the current 'epidemic' of obesity in most industrialized countries.