A longitudinal study of serum insulin and insulin resistance as predictors of weight and body fat gain in African American and Caucasian children

BACKGROUND

The influence of insulin and insulin resistance (IR) on children's weight and fat gain is unclear.

OBJECTIVE

To evaluate insulin and IR as predictors of weight and body fat gain in children at high risk for adult obesity. We hypothesized that baseline IR would be positively associated with follow-up body mass index (BMI) and fat mass.

SUBJECTS/METHODS

Two hundred and forty-nine healthy African American and Caucasian children aged 6-12 years at high risk for adult obesity because of early-onset childhood overweight and/or parental overweight were followed for up to 15 years with repeated BMI and fat mass measurements. We examined baseline serum insulin and homeostasis model of assessment-IR (HOMA-IR) as predictors of follow-up BMI Z-score and fat mass by dual-energy X-ray absorptiometry in mixed model longitudinal analyses accounting for baseline body composition, pubertal stage, sociodemographic factors and follow-up interval.

RESULTS

At baseline, 39% were obese (BMI⩾95th percentile for age/sex). Data from 1335 annual visits were examined. Children were followed for an average of 7.2±4.3 years, with a maximum follow-up of 15 years. After accounting for covariates, neither baseline insulin nor HOMA-IR was significantly associated with follow-up BMI (Ps>0.26), BMIz score (Ps>0.22), fat mass (Ps>0.78) or fat mass percentage (Ps>0.71). In all models, baseline BMI (P<0.0001), body fat mass (P<0.0001) and percentage of fat (P<0.001) were strong positive predictors for change in BMI and fat mass. In models restricted to children without obesity at baseline, some but not all models had significant interaction terms between body adiposity and insulinemia/HOMA-IR that suggested less gain in mass among those with greater insulin or IR. The opposite was found in some models restricted to children with obesity at baseline.

CONCLUSIONS

In middle childhood, BMI and fat mass, but not insulin or IR, are strong predictors of children's gains in BMI and fat mass during adolescence.

Binge Eating Disorder Affects Outcome of Comprehensive Very-Low-Calorie Diet Treatment

To determine the effects of binge eating disorder (BED) on weight loss and maintenance in women undergoing treatment for obesity, we studied the weight changes of 38 women (body mass index > 30 kg/m2), 21 of whom met proposed criteria for BED and 17 of whom reported few problems with binge eating, during and after a 26-week comprehensive very-low-calorie diet (VLCD) treatment program. All 17 subjects without and 16/21 subjects with BED returned for four follow-up visits over 12 months (p = 0.05). While a similar proportion of subjects with and without BED reported absolute adherence to both the modified fast and refeeding, those with BED showed a significantly different distribution in energy intake from those without BED, with fewer small and more large lapses among those who deviated from the diet (p < 0.05). There was no significant difference in mean weight loss over the 26 weeks of treatment, but subjects with BED showed significantly diminished weight loss during the middle third of treatment (p < 0.05). Black subjects, regardless of the presence of BED, lost significantly less weight during treatment than white subjects (p < 0.005). Although there was no significant difference in mean weight loss at any of the four follow-up visits between subjects with and without BED, 25% of subjects with BED had regained > 50% of their lost weight by three-month follow-up, vs. no subjects without the disorder (p < 0.05). One year after completing treatment, approximately half of BED (+) and BED (-) subjects had a good outcome, maintaining a weight loss > or = 10% of initial body weight. However, 35% of subjects with BED, and none of the subjects without BED, had a poor outcome (p < 0.05). We conclude that many individuals with BED will respond well to a medically supervised comprehensive VLCD program, attaining medically significant weight loss. However, this subgroup appears to be at risk for early major regain of lost weight and for poor outcome one year following weight-loss treatment.

Binge Eating Disorder: Current Knowledge and Future Directions

Binge eating disorder (BED) is a newly characterized eating disorder that encompasses individuals who have severe distress and dysfunction due to binge eating, but who do not regularly engage in inappropriate compensatory behaviors. While relatively uncommon in the general community, BED becomes more prevalent with increasing severity of obesity. BED is associated with early onset of obesity, frequent weight cycling, body shape disparagement, and psychiatric disorders. These associations occur independent of the degree of obesity. Although many individuals with BED have good short-term weight loss regardless of treatment modality, as a group they may be prone to greater attrition during weight-loss treatment and more rapid regain of lost weight. Current treatments geared toward binge eating behaviors include antidepressant medications, cognitive behavioral psychotherapy, and interpersonal psychotherapy; however, these treatments have little efficacy in promoting weight loss, and only modest success in long-term reduction of binge eating. As a significant proportion of obese individuals entering weight-loss treatment and research programs are likely to meet criteria for BED, those conducting clinical research should be aware of this distinct subgroup and determine the contribution of BED to outcome measures.

Construct validity of the emotional eating scale adapted for children and adolescents

BACKGROUND

Emotional eating, defined as eating in response to a range of negative emotions, is common in youths. Yet, there are few easily administered and well-validated methods to assess emotional eating in pediatric populations.

OBJECTIVE

The current study tested the construct validity of the Emotional Eating Scale (EES) Adapted for Children and Adolescents (EES-C) by examining its relationship to observed emotional eating at laboratory test meals.

METHOD

A total of 151 youths (8-18 years) participated in two multi-item lunch buffet meals on separate days. They ate ad libitum after being instructed to 'eat as much as you would at a normal meal' or to 'let yourself go and eat as much as you want'. State negative affect was assessed immediately before each meal. The EES-C was completed 3 months, on average, before the first test meal.

RESULTS

Among youths with high EES-C total scores, but not low EES-C scores, higher pre-meal state negative affect was related to greater total energy intake at both meals, with and without the inclusion of age, race, sex and body mass index (BMI) standard deviation as covariates (ps<0.03).

DISCUSSION

The EES-C demonstrates good construct validity for children and adolescents' observed energy intake across laboratory test meals designed to capture both normal and disinhibited eating. Future research is required to evaluate the construct validity of the EES-C in the natural environment and the predictive validity of the EES-C longitudinally.

Assessing the body composition of 6-17-year-old Black and White girls in field studies

The purpose of the study was to develop ethnic-specific equations for fat-free mass (FFM) from selected anthropometric dimensions and bioelectrical impedance measures of resistance (R) and reactance (Xc) for use in the NHLBI Growth and Heath Study. Using dual-energy X-ray absorptiometry measures of body composition as the dependent variable and field measures of body composition by anthropometry and bioelectrical impedance as the explanatory variables, ethnic-specific prediction equations were developed on a sample of girls representing a wide range of ages and BMI. The equations were cross-validated using (1) the Prediction of Sum of Squares (PRESS) statistic and (2) an independent sample of 20 girls of each race from a study conducted at the National Institute of Child Health and Human Development (NICHD). Subjects were 65 White and 61 Black girls 6-17 years of age. The best race-specific equations for FFM each explained 99% and 97% of the variance in the White and Black girls, respectively. Root mean square errors (RMSE) ranged from 1.14 to 1.95 kg. The equation for Black girls used Stature2/Resistance (R), weight, and reactance (Xc) as predictor variables; the equation for White girls used Stature2/R, weight, and triceps skinfold thickness. The results indicate that (1) equations to predict FFM in girls should be ethnic-specific and that (2) accurate values for TBF and %BF can be calculated from the predicted FFM.

Osteoarthritis: new insights. Part 1: the disease and its risk factors

Osteoarthritis is the most common form of arthritis, affecting millions of people in the United States. It is a complex disease whose etiology bridges biomechanics and biochemistry. Evidence is growing for the role of systemic factors (such as genetics, dietary intake, estrogen use, and bone density) and of local biomechanical factors (such as muscle weakness, obesity, and joint laxity). These risk factors are particularly important in weight-bearing joints, and modifying them may present opportunities for prevention of osteoarthritis-related pain and disability. Major advances in management to reduce pain and disability are yielding a panoply of available treatments ranging from nutriceuticals to chondrocyte transplantation, new oral anti-inflammatory medications, and health education. This article is part 1 of a two-part summary of a National Institutes of Health conference. The conference brought together experts on osteoarthritis from diverse backgrounds and provided a multidisciplinary and comprehensive summary of recent advances in the prevention of osteoarthritis onset, progression, and disability. Part 1 focuses on a new understanding of what osteoarthritis is and on risk factors that predispose to disease occurrence. It concludes with a discussion of the impact of osteoarthritis on disability.

Hypothalamic-pituitary-adrenal axis activity during exercise in African American and Caucasian women

African American women have a greater prevalence of obesity than Caucasian women, but the reasons for this difference are not known. We have investigated whether activity of the hypothalamic-pituitary adrenal axis plays a role in this phenomenon. Previous studies have shown that plasma ACTH immunoreactivity (ACTH-IR) of African American women, measured after ovine CRH (oCRH) stimulation, is significantly greater than ACTH-IR of Caucasian women, but is not accompanied by greater plasma cortisol concentrations. Analysis by high pressure liquid chromatography has demonstrated that after oCRH stimulation, the plasma ACTH-IR of African American women contains many nonintact ACTH fragments not found in Caucasians. To determine whether these racial differences in ACTH-IR secretion are an artifact of exogenous oCRH administration or are also found after a physiological stimulus for ACTH secretion, we measured hormones of the hypothalamic-pituitary adrenal axis before and after a standardized, maximal exercise treadmill test in 16 African American and 19 Caucasian healthy women matched for age, socioeconomic status, and body mass index. The intensity of exercise performed was similar in the two groups, as determined by duration of exercise, perceived intensity of exertion, plasma lactate, maximal heart rate, and maximum oxygen uptake. Basal ACTH-IR measured by RIA or immunoradiometric assay and cortisol were similar in African Americans and Caucasians. Plasma ACTH-IR, measured 10 min after completion of exercise, was significantly greater in African Americans than in Caucasians [by RIA: mean +/- SD ACTH-IR, 47.1 +/- 30.9 vs. 25.4 +/- 16.7 pmol/L (P < 0.01); by immunoradiometric assay: ACTH-IR, 45.9 +/- 43.2 vs. 21.1 +/- 14.6 pmol/L (P < 0.05)]. However, plasma cortisol after exercise was not different (450.2 +/- 157.7 vs. 483.6 +/- 180.4 nmol/L; P = 0.57). We conclude that ACTH-IR is significantly greater in African American than in Caucasian women after intense exercise. The ACTH-IR of African Americans and Caucasians does not appear to be equipotent at adrenal melanocortin-2 receptors, because the greater ACTH-IR of African Americans does not lead to greater cortisol secretion. Whether some components of the ACTH-IR detected in African Americans affect signal transduction of the hypothalamic melanocortin-4 receptors implicated in body weight regulation and thus predispose African American women to weight gain without altering plasma cortisol remains to be determined.

Obesity: what mental health professionals need to know

OBJECTIVE

Obesity is a highly prevalent condition with significant health implications. This report summarizes recent clinically relevant findings concerning the pathogenesis and treatment of obesity and considers their implications for psychiatric diagnosis and management.

METHOD

The authors conducted selective reviews of the literature from the last 10 years. Topics included the biological and behavioral factors that contribute to the onset and maintenance of obesity, the relationship between obesity and psychiatric illness and treatment, and the questions of whether and how obesity should be treated.

RESULTS

Genetic effects, some mediated by eating behavior, contribute importantly to the potential for obesity, the expression of which is promoted by environmental factors that increase the availability of calorically dense foods and discourage activity. There appear to be behaviorally distinct subsets of obese persons who display particular patterns of disordered eating and elevated rates of psychopathology. Treatment with psychotropic medications may contribute to obesity in ways that are only partly understood. Although successful obesity treatment is associated with clear health benefits and available treatments offer benefit to some, relapse remains the rule.

CONCLUSIONS

Although the presence or development of obesity is a daunting problem, it should not be ignored by mental health professionals. Treatment should address not only obesity per se, but also its effects on self-esteem in a hostile cultural climate. Ongoing developments in basic and clinical research are likely to increase the range, efficacy, and acceptability of treatment options in the years ahead.

A prospective study of holiday weight gain

BACKGROUND

It is commonly asserted that the average American gains 5 lb (2.3 kg) or more over the holiday period between Thanksgiving and New Year's Day, yet few data support this statement.

METHODS

To estimate actual holiday-related weight variation, we measured body weight in a convenience sample of 195 adults. The subjects were weighed four times at intervals of six to eight weeks, so that weight change was determined for three periods: preholiday (from late September or early October to mid-November), holiday (from mid-November to early or mid-January), and postholiday (from early or mid-January to late February or early March). A final measurement of body weight was obtained in 165 subjects the following September or October. Data on other vital signs and self-reported health measures were obtained from the patients in order to mask the main outcome of interest.

RESULTS

The mean (+/-SD) weight increased significantly during the holiday period (gain, 0.37+/-1.52 kg; P<0.001), but not during the preholiday period (gain, 0.18+/-1.49 kg; P=0.09) or the postholiday period (loss, 0.07+/-1.14 kg; P=0.36). As compared with their weight in late September or early October, the study subjects had an average net weight gain of 0.48+/-2.22 kg in late February or March (P=0.003). Between February or March and the next September or early October, there was no significant additional change in weight (gain, 0.21 kg+/-2.3 kg; P=0.13) for the 165 participants who returned for follow-up.

CONCLUSIONS

The average holiday weight gain is less than commonly asserted. Since this gain is not reversed during the spring or summer months, the net 0.48-kg weight gain in the fall and winter probably contributes to the increase in body weight that frequently occurs during adulthood.

Report of a National Institutes of Health--Centers for Disease Control and Prevention workshop on the feasibility of conducting a randomized clinical trial to estimate the long-term health effects of intentional weight loss in obese persons

A workshop was convened in 1997 by the National Institutes of Health and the Centers for Disease Control and Prevention to consider the need for and feasibility of conducting a randomized clinical trial to estimate the long-term health effects of intentional weight loss in obese persons. Although the benefits of weight loss in obese individuals may seem obvious, little information is available showing that intentional weight loss improves long-term health outcomes. Observational studies may be unable to provide convincing answers about the magnitude and direction of the health effects of intentional weight loss. Workshop participants agreed that a well-designed randomized clinical trial could answer several questions necessary for developing a rational clinical and public health policy for treating obesity. Such information will ultimately provide needed guidance on the risks and benefits of weight loss to health care providers and payers, as well as to millions of obese Americans.

Report of the National Institutes of Health (NIH) Workshop on the Development of Research Priorities in Eating Disorders

The National Institutes of Health (NIH) Workshop on the Development of Research Priorities in Eating Disorders was convened in New York on April 24 and 25, 1996. The goals of the workshop were (1) to identify important unanswered questions in the study and treatment of eating disorders, (2) to discuss potentially fruitful approaches to answering these questions through basic and clinical research, and (3) to assist the NIH and other funding agencies in assigning priorities for research on eating disorders. The program consisted of a series of brief presentations by moderators, each followed by facilitated discussion of the topic with members of the audience. Three reporters (CMG, MJD, FMC) took detailed notes of the proceedings, which have been incorporated into this article. A summary of this workshop is presented, along with recommendations for future research that were identified by workshop participants.

Resting metabolic rate in African-American and Caucasian girls

Recent studies have found a lower resting metabolic rate (RMR) in African-American (AA) women with obesity as compared with Caucasian (C) women with obesity. It is unknown if this difference in RMR is seen in prepubertal girls or in those of average body weight. Therefore, we studied RMR in 21 AA and 24 C girls, ages 7-10, who were well matched for age, weight, body mass index (BMI), and pubertal status. All had BMI between 15% and 85% for age and race, based on data from the First National Health and Nutrition Examination Survey. Fat free mass (FFM) was measured by dual-energy X-ray absorptiometry. RMR was measured with a Deltatrac indirect calorimeter under controlled conditions after the subjects underwent an overnight fast. The slopes of the regression equations were similar for both groups (p = 0.7). After adjustment for FEM, the AA girls had a significantly lower RMR than did the C girls (-92 +/- 32 kcal/d, p = 0.007 by analysis of covariance). This significance was maintained after exclusion of total body bone mineral content. These data suggest that normal-weight prepubertal AA girls may have reduced resting energy expenditure compared with C girls.

Differences in corticotropin-releasing hormone-stimulated adrenocorticotropin and cortisol before and after weight loss

Little is known about the effects of intentional weight loss on the function of the hypothalamic-pituitary-adrenal (HPA) axis of obese individuals. We studied the HPA axis of 34 healthy obese women (body mass index, 40.2 +/- 7.9 kg/m2) before and after a 21.0 +/- 7.9-kg weight loss induced by a 26-week weight loss program that included 12 weeks of a 3350 kJ/day (800 Cal/day) liquid formula diet, 6 weeks of gradual refeeding, and 6 weeks of caloric stabilization at 5020-6280 kJ/day (1200-1500 Cal/day). Obese subjects were evaluated twice: before caloric restriction and during the last 3 weeks of caloric stabilization with a 3-h evening 1 microg/kg ovine CRH (oCRH) stimulation test. CRH-stimulated ACTH and cortisol values were compared to those of a control group of 12 normal weight women. Before caloric restriction, both ACTH and cortisol responses to oCRH were similar in obese women and normal weight controls. Weight loss did not significantly alter the ACTH response to oCRH; however, the total plasma cortisol response to oCRH decreased significantly with weight loss (area under the curve, 96,320 +/- 21,040 nmol/L x min before weight loss; 82,450 +/- 22,460 nmol/L x min after weight loss; P < 0.001). Cortisol-binding globulin also decreased significantly after weight loss (2,270 +/- 1,050 nmol/L) compared either to values obtained before weight loss (3,590 +/- 1,360 nmol/L; P < 0.001) or to those of normal weight controls (3,910 +/- 1,400 nmol/L; P < 0.001). Assay for plasma free cortisol, either before or 180 min after oCRH treatment, showed no significant changes in cortisol responses resulting from weight loss. As plasma free cortisol was not altered by weight reduction, the decrease in the total cortisol response to oCRH after weight loss appears to be secondary to significant decreases in cortisol-binding globulin. We conclude that when obese women lose large amounts of weight with a 3350 kJ/day, very low energy diet, such weight reduction does not significantly affect the HPA axis.

Differences in body composition of black and white girls

Adults have racial differences in body composition that may modulate risks resulting from obesity. Although black and white children have been shown previously to have differences in bone mineral density and subcutaneous body fat, differences in visceral adipose tissue have not been evaluated. We studied 20 black and 20 white normal-weight girls aged 7-10 y, who were matched for weight, body mass index (BMI), bone age, chronological age, Tanner breast stage, and socioeconomic status. Each underwent anthropometric measurements, bioelectrical impedance analysis, dual-energy X-ray absorptiometry (DXA), and abdominal magnetic resonance imaging (MRI) for determination of total (TAT), visceral (VAT), and subcutaneous (SAT) adipose tissue. Serum lipids and fasting and 2-h oral-glucose-tolerance test (OGTT) glucose and insulin concentrations were also measured. There were no differences between groups in absolute waist circumference or waist-to-hip ratio, but waist-to-thigh ratio was smaller in black than in white girls. Black girls had greater bone mineral density and less TAT, VAT, and SAT than whites. VAT was not significantly correlated with any measure of insulin, or with serum lipids. However, both basal and 2-h OGTT serum insulin were significantly correlated with SAT as assessed by MRI in black girls (r2 = 0.46 for basal insulin, P = 0.001: r2 = 0.31 for 2-h insulin, P = 0.01) but not in white girls (r2 < 0.05, for basal and 2-h insulin, NS). We conclude that there are significant racial differences in body composition and differences in the strength of association between abdominal adipose tissue depots and insulin sensitivity in black and white girls.

Etiology of the differences in corticotropin-releasing hormone-induced adrenocorticotropin secretion of black and white women

After i.v. oCRH, plasma immunoreactive ACTH (ACTH-IR) is significantly greater in blacks than in whites; however, there is no corresponding increase in cortisol secretion. To test the hypothesis that there are black-white differences in adrenal responsiveness to ACTH that underlie this phenomenon, weight-, age-, and education-matched black (n = 10) and white (n = 10) women were i.v. infused with 5 differing doses of ACTH1-24 (0, 0.003, 0.01, 0.1, and 1 microgram/kg) with measured plasma cortisol and DHEA. To test the alternative hypothesis that greater post-CRH plasma ACTH-IR in blacks is caused by qualitative differences in circulating ACTH-immunoreactive peptides, we collected pre- and post-CRH plasma from 5 black and 5 white women and measured ACTH-IR after sample fractionation, using high-pressure liquid chromatography. There were no racial differences in adrenal responsiveness to differing doses of ACTH1-24 and no differences in the distribution of the forms of ACTH-IR before CRH. After CRH, whites had predominant ACTH-IR peaks at the retention times of ACTH1-39 and ACTH1-39-sulfoxide, whereas blacks had prominent peaks at several additional retention times. The post-CRH ratio of intact to total ACTH was significantly lower in blacks than in whites (0.27 +/- 0.17 vs. 0.71 +/- 0.17, P < 0.003). We conclude that there are qualitative differences in post-CRH circulating ACTH-IR in blacks and whites, leading to a greater immunoreactive to bioactive ACTH ratio in blacks. Such differences in the circulating forms of ACTH can account for greater CRH-stimulated ACTH-IR in blacks.

Differences in the hypothalamic-pituitary-adrenal axis of black girls and white girls

After intravenous administration of ovine corticotropin-releasing hormone (CRH), the plasma corticotropin (ACTH) concentrations of adult black women and men are approximately twice as high as those of adult white women and men; however, there are no corresponding differences in cortisol response. To determine whether these differences in ACTH secretion are also present in prepubertal and early pubertal girls, we studied the hypothalamic-pituitary-adrenal axis of 19 black and 19 white girls of normal weight (age 7 to 10 years) who were matched for body mass index, age, and socioeconomic status. Measures of cortisol's effects, including waist circumference, waist/hip ratio, and fasting insulin and glucose levels, were obtained and related to the ACTH and cortisol responses to 1 micrograms/kg CRH. There were no racial differences in waist circumference, waist/hip ratio, fasting glucose or insulin levels, baseline free or total plasma cortisol levels, baseline ACTH concentrations, or the plasma cortisol response to CRH. However, CRH-stimulated plasma ACTH concentrations, measured in a polyclonal radio-immunoassay, were significantly greater in prepubertal and early pubertal black girls than in white girls at all time points between 15 and 90 minutes after administration of CRH (area under curve (AUC 1754 +/- 121 pmol/L/min in black girls vs 1304 +/- 124 pmol/L/min in white girls, p < 0.001). This difference was confirmed by an immunoradiometric assay believed to be specific for intact ACTH (AUC 1634 +/- 139 pmol/L/min in black girls vs 1224 +/- 104 pmol/L/min in white girls, p < 0.001). Neither ACTH AUC nor cortisol AUC was significantly correlated with body mass index in either black or white girls. We conclude that there are differences in the hypothalamic-pituitary-adrenal axis of prepubertal and early pubertal black and white girls similar to those found previously in adult women. The cause of these differences remains to be elucidated.

Biological correlates of binge eating

Eating disorders are associated with numerous biological perturbations; however, sorting out cause from effect is difficult. Neuroendocrine and metabolic abnormalities are seen in both anorexia nervosa and bulimia nervosa, but they have not been described in binge eating disorder, in which neither starvation nor compensatory behaviors are present. Although these findings may reflect biologic differences among subgroups of binge eaters, an alternative explanation is that many of the biological correlates of binge eating are the result of metabolic derangement secondary to starvation and/or purging. The identification of binge eating disorder provides an opportunity to study the causes and concomitants of binge eating in the absence of compensatory behaviors.

Role of Behavioral Therapy in the Management of Obesity

Behavioral therapy for obesity that is, the application of learning theory to obesity treatment is now a standard component of weight-loss programs. The hallmark of behavioral therapy for obesity is self-monitoring of eating behavior, but techniques of stimulus control, self-reward, cognitive restructuring, nutrition education, and physical activity are also emphasized. Although behavioral treatment programs that incorporate lengthier and more intensive regimens are often successful in producing short-term weight loss, most patients have regained much or all of their lost weight at long-term follow-up. One approach to this problem has been to supplement behavioral treatment with other modalities such as very-low-calorie diets, surgical procedures, and medication. Whatever the initial treatment, obesity clearly must be approached as a chronic disorder that necessitates long-term intervention, and relapse prevention and weight maintenance strategies are crucial for long-term success. Another important development in behavioral treatment of obesity has been the attempt to identify subgroups of obese persons, such as those with uncontrolled binge eating, who might benefit from specific management approaches. Treatment programs for binge eating are strongly influenced by techniques developed for other types of eating disorders such as bulimia. Although use of only behavioral therapy is insufficient, it has an important adjunctive role for many patients particularly as we improve our abilities to tailor treatment to the individual subject and to promote long-term weight maintenance.

Pyroglutamyl peptidase-II ("thyroliberinase") activity in human serum: influence of weight and thyroid status

The tripeptide hormone, TRH, is metabolized by three enzymes, the most specific of which is pyroglutamyl peptide hydrolase-II (also termed thyroliberinase), a metalloenzyme present in serum and brain. Because pyroglutamyl peptidase-II activity in rat serum is regulated by thyroid hormone levels, we tested the hypothesis that this activity is similarly altered in humans. We studied serum pyroglutamyl peptidase-II activity in 6 patients with hyperthyroidism, 18 patients with hypothyroidism, and 31 euthyroid, normal weight volunteers. Because TRH [or its metabolite cyclo(His-Pro)] is believed to be an important hormone regulating appetite and metabolism, we also evaluated pyroglutamyl peptidase-II activity in 27 euthyroid patients with obesity. Serum pyroglutamyl peptidase-II activity was elevated in patients with hypothyroidism (mean +/- SEM, 33.9 +/- 3.7 nmol/mL.h) compared to that in euthyroid, normal weight volunteers (24.5 +/- 2.8 nmol/mL.h; P < 0.05), but not that in patients with hyperthyroidism (28.3 +/- 4.1 nmol/mL.h; P = NS). Euthyroid obese patients had the highest pyroglutamyl peptidase-II activity (43.6 +/- 2.8 nmol/mL.h; P < 0.0001 vs. normal weight volunteers). Pyroglutamyl peptidase-II activity was positively correlated with body mass index (r2 = 0.30; P < 0.0001). After correction for body mass index, there were no difference in pyroglutamyl peptidase-II activity in hypothyroid, hyperthyroid, and euthyroid individuals. We conclude that serum pyroglutamyl peptidase-II activity is regulated by, or regulates, body weight.

Visceral adipose tissue differences in black and white women

Fat distribution and metabolic variables were studied in 8 black and 10 white age- and weight-matched obese women undergoing a 6-mo weight-reducing regimen. Fat patterning was determined by using anthropometry and computed tomography to quantitate total, subcutaneous, and visceral adipose tissue (VAT) areas at the L2-L3 and L4-L5 levels of the lumbar spine, before, during, and after a modified fast. Black women had smaller depots of VAT than white women at both the L2-L3 (P = 0.004) and L4-L5 (P = 0.054) sites. Differences persisted after an average 17.2-kg weight loss. Although waist-hip ratio was similar in both groups, black women had 23% less VAT than white women (P = 0.007). Black women had significantly lower plasma glucose (P = 0.031) and triglycerides (P = 0.006) with significantly higher plasma high-density-lipoprotein concentrations (P < 0.001). Data from this study suggest that racial differences exist in VAT and metabolic risk factors for obesity-related illness.

Differences in the hypothalamic-pituitary-adrenal axis of black and white men

We previously found that, following intravenous administration of ovine corticotropin-releasing hormone (CRH), the plasma ACTH concentrations of Black women were approximately twice as high as those of White women; however, there were no corresponding differences in cortisol response. To determine whether this difference in ACTH secretion is also present in men, we studied the hypothalamic-pituitary-adrenal axis of 10 Black and 10 White weight-, age-, and education-matched men. Waist-to-hip ratio, 24-hour urine free cortisol excretion, and ACTH and cortisol responses to 1 microgram/kg ovine CRH were determined. There were no racial differences in waist-to-hip ratio, 24-hour urine free cortisol excretion, baseline free or total plasma cortisol and ACTH concentrations, or plasma cortisol response to CRH. However, CRH-stimulated plasma ACTH concentrations, measured in an extraction polyclonal radioimmunoassay, were significantly greater in Blacks than in Whites at all time points between 30 and 180 min after administration of CRH (area under curve (AUC) 1,796 +/- 245 pmol/l.min in Blacks vs. 1,278 +/- 121 pmol/l.min in Whites, p < 0.001). Neither cortisol nor ACTH AUCs were significantly correlated with Body Mass Index in Black or White men. We conclude that there are differences in the HPA axis of Black and White men similar to those found previously in women. The physiology underlying these differences remains to be understood.

Recorded food intake of obese women with binge eating disorder before and after weight loss

Because binge eating in obese individuals has been postulated to be a reaction to dietary restriction, we examined the recorded food intake of 17 obese women with and 16 obese women without binge eating disorder (BED) during 1-week periods before and 3 months after a very low calorie diet program in order to determine the effects of dietary restriction on binge eating frequency and severity. Before weight loss, rather than reporting severe caloric restriction, women with BED reported greater average energy intake than nonbinge eaters on both a total (2707 vs. 1869 k cal/day, p < .01) and weight-adjusted (25.1 vs. 18.1 kcal/kg, p < .01) basis, with both higher intake on nonbinge days and an increased frequency of binge days. After weight loss, there was no significant difference in energy intake, on either a total or weight-adjusted basis, between subjects with and without BED. Although average daily energy intake fell for both groups after weight loss, only subjects with BED reported significantly decreased energy intake when adjusted for change in body weight. This resulted from decreased intake on nonbinge days and a decreased frequency of binge days. Before weight loss, subjects with BED reported an average energy intake equivalent to 94% of their predicted energy expenditure. Whereas subjects without BED reported intake only 64% of predicted (p = .002). After weight loss, there was no significant difference between subjects with and without BED in the percentage of predicted energy expenditure reported as intake (64% vs. 58%). Restraint was similar in both groups before weight loss, but those with BED reported greater hunger and disinhibition. After weight loss treatment, restraint increased significantly, whereas disinhibition and hunger remained elevated in subjects with BED. Disinhibition, rather than restraint, appears to be a major contributor to the disordered eating of these individuals. Unlike normal-weight women with bulimia nervosa, dietary restriction does not appear to worsen symptoms of binge eating in obese women with BED. Over the short term, subjects with BED may respond to a standard weight loss treatment program with improvements in binge eating behaviors.

Association of binge eating disorder and psychiatric comorbidity in obese subjects

OBJECTIVE

The authors determined the prevalence of binge eating disorder in a self-referred study group of moderately and severely obese subjects and investigated whether binge eating disorder was associated with psychiatric disorders, a history of psychotherapy, a family history of psychiatric illness, or a history of sexual abuse.

METHOD

They interviewed 89 obese women and 39 obese men (body mass index > 30 kg/m2) who were not currently in weight loss treatment, using the Binge Eating Disorder Clinical Interview, the Structured Clinical Interview for DSM-III-R, and the Structured Clinical Interview for DSM-III-R Personality Disorders.

RESULTS

Forty-three (34%) of the subjects met criteria for binge eating disorder--33 women and 10 men. Black and white subjects had similar rates of binge eating disorder. Subjects with binge eating disorder were significantly more likely than those without the disorder to have a lifetime prevalence of a DSM-III-R axis I or axis II diagnosis and to have undergone psychotherapy or counseling. The lifetime rates of major depression, panic disorder, bulimia nervosa, borderline personality disorder, and avoidant personality disorder were all significantly higher in subjects with binge eating disorder. The rate of reported sexual abuse was not higher among subjects with binge eating disorder; however, they were significantly more likely to have a family history of substance abuse. The relative risks for psychiatric disorders were higher in both moderately and severely obese subjects with binge eating disorder than in those without the disorder.

CONCLUSIONS

Among both moderately and severely obese subjects, binge eating disorder is associated with higher rates of axis I and axis II psychiatric disorders.

Differences in the hypothalamic-pituitary-adrenal axis of black and white women

Alterations in the activity of the hypothalamic-pituitary-adrenal (HPA) axis have been associated with obesity in humans and animals. To explore possible mechanisms responsible for the higher prevalence of obesity and its associated comorbid conditions in the black population, we studied the HPA axis of 18 black and 30 white weight- and age-matched nonobese and obese women. Waist to hip ratio, 24-h urinary free cortisol excretion, plasma cortisol responses to dexamethasone, and plasma ACTH and cortisol responses to 1 micrograms/kg ovine CRH were determined. There were no racial differences in waist to hip ratio, 24-h urinary free cortisol excretion, dexamethasone suppressibility of plasma cortisol, baseline plasma cortisol and ACTH concentrations, or plasma cortisol response to CRH. However, CRH-stimulated plasma ACTH concentrations, measured in an extraction polyclonal RIA, were significantly greater in blacks than in whites at all time points, beginning 5 min after the administration of CRH [area under the curve (AUC), 2463 +/- 288 pmol/L.min in blacks vs. 1185 +/- 78 in whites; P < 0.001]. These differences persisted when ACTH was measured by a 2-site direct immunoradiometric assay measuring the intact ACTH-(1-39) molecule (AUC, 1292 +/- 177 pmol/L.min in blacks vs. 504 +/- 95 in whites; P < 0.002). There was no significant correlation between body mass index and either cortisol or ACTH AUCs for either race, with blacks showing persistently elevated AUC for ACTH compared to whites, regardless of weight. We conclude that there are differences in the HPA axis of black and white women. How these differences may relate to the increased prevalence of obesity in the black population remains to be determined.

Normal dexamethasone suppression in obese binge and nonbinge eaters with rapid weight loss

Natural or experimental starvation is frequently associated with hypercortisolism, reflected as incomplete suppression of serum cortisol after dexamethasone. To determine whether rapid weight loss per se or some other aspect of starvation induces disruption of the hypothalamic-pituitary-adrenal (HPA) axis, we evaluated 2 categories of obese women (body mass index > 30 kg/m2) undergoing rapid weight loss: binge eaters (n = 12) and nonbinge eaters (n = 8). We performed psychometric evaluation and 1 mg overnight dexamethasone suppression tests in the obese subjects, as well as in 12 race- and age-matched normal-weight women. The obese women were tested before and after 12 weeks of a 3349 kJ/day (800 kcal/day) liquid formula diet, and lost an average of 19.3 kg, which represented 17.3% of their total body weight. Binge eaters, who were initially more depressed than either nonbinge eaters or normal-weight controls, had a significant amelioration of their symptoms with weight loss. Neither group had evidence of disruption of the HPA axis before or after weight loss. Thus, the rate of failure to suppress cortisol after dexamethasone was approximately 10% in each of the obese and control groups, and did not differ between the pre- and postweight loss condition or between binge eaters and nonbinge eaters. Serum free T4 was unchanged, whereas T3 fell significantly with weight loss. We conclude that weight loss may improve affect in the obese without altering HPA axis activity, and postulate that one of the concomitants of restricted energy intake, perhaps in combination with a threshold body weight, may be of greater importance in causing abnormalities of dexamethasone suppression testing than rapid weight loss per se.

A practical approach to treatment of the obese patient

Obesity is one of the most common conditions encountered by primary care physicians, yet both physicians and patients are often frustrated by current approaches to its management. Recent advances in our understanding of obesity enable the physician to evaluate the contributions of biologic and environmental factors to the patient's obesity, to determine the degree of medical risk posed by the obesity, and to establish realistic goals for treatment. The chronic and relapsing nature of obesity requires ongoing support and vigilance. An individualized approach to obesity management, based on careful evaluation of biologic, psychologic, and social factors, can be successfully developed and implemented by the office-based primary care physician.

Food selection and intake of obese women with binge-eating disorder

We studied food selection and intake of 19 women [body mass index (in kg/m2) > 30] [corrected], 10 of whom met proposed DSM-IV criteria for binge-eating disorder (BED). All subjects ate two multicourse meals in the laboratory, and were given tape-recorded instructions at each meal either to binge or eat in a normal fashion. Subjects with BED consumed significantly more energy than did subjects without BED at both the binge [12,400 vs 8440 kJ (2963 vs 2017 kcal), P < 0.005] and normal [9810 vs 6870 kJ (2343 vs 1640 kcal), P < 0.02] meals. During the binge meal subjects with BED consumed a greater percentage of energy as fat (38.9% vs 33.5%, P < 0.002) and a lesser percentage as protein (11.4% vs 15.4%, P < 0.01) than did subjects without BED. There were no differences in macronutrient composition of food choices between groups in the normal meal. Obese women who meet criteria for BED show differences in both intake and macronutrient composition of food choices from obese women who do not meet these criteria when asked to eat in a laboratory setting, supporting the validity of this new diagnosis.

Telephone triage by primary care physicians

To determine if experienced primary care physicians are more likely to reach correct decisions on the telephone than their less experienced colleagues, we asked 31 first-year and 29 third-year residents, 21 faculty, and 36 private practitioners in pediatrics and family practice to evaluate three pediatric patients via a telephone interview with a simulated mother and to decide whether each patient needed to be seen that evening. Compared with first-year residents, the third-year residents, faculty and private practitioners decided less frequently to see children who were not severely ill (P less than .05) or injured (P less than .01); however, less than half obtained histories considered adequate to rule out potential serious illnesses. Faculty did better than either residents or private practitioners in managing a severely dehydrated child; 100% of the faculty, but less than 60% of the residents or private practitioners, chose to see the patient promptly (P less than .001). More than one third of all residents and private practitioners reached inappropriate management decisions despite obtaining information that should have altered their decisions. In these simulations, experience in private practice was not associated with improved telephone management of very sick children. Faculty physicians appeared to be better able to identify severely ill children without inappropriately evaluating those who were less ill. In all three simulations, attainment of the correct decision appeared to be determined not by the number or type of questions asked, but rather by the physician's interpretation of the information collected.

Bulimia nervosa: the role of the family physician

Bulimia nervosa is an eating disorder characterized by binge eating and purging. The disorder is estimated to occur in up to 5 percent of young women. Despite severe psychosocial impairment and potentially serious medical complications, patients do not usually reveal their bulimic behavior to a physician unless directly asked. Promising treatments include cognitive-behavioral psychotherapy and antidepressant medications.