Investigation of obesity

Analysis of the Relationship between Obesity Factors and Health-Related Physical Fitness Factors among People with Intellectual Disabilities in South Korea

Little is known about the relationship between health-related physical fitness factors and obesity-related factors in individuals with intellectual disabilities. We investigated the prevalence of obesity and the relationship between obesity-related factors and health-related physical fitness factors among people with intellectual disabilities in South Korea to identify the physical fitness factors that influence the degree of obesity. For obesity-related factors, we measured body composition (height, weight, body mass index—BMI, and body fat percentage) of 108 subjects with intellectual disabilities (mean ± standard deviation; age = 24.4 ± 8.45 years). For health-related physical fitness factors, we measured muscular strength, muscular endurance, and flexibility. There was a significant negative correlation between muscular endurance and obesity factors (BMI, r = −0.306, p < 0.01; body fat percentage, r = −0.402, p < 0.01). Further, the prevalence of obesity (34.3%) and being overweight (17.6%) among people with intellectual disabilities was high in South Korea. In addition, muscular endurance was found to have a significant effect on the obesity level (β = −0.239, p < 0.000). This suggests that a program that considers muscular endurance should be prioritized when implementing an exercise intervention strategy for the treatment of overweight and obesity among people with intellectual disabilities.

Association Between Body Mass Index and Complications in Acoustic Neuroma Surgery

Objectives

Elevated body mass index (BMI) is a risk factor for surgical complications, but data in acoustic neuroma surgery are conflicting and limited to small single-institution studies. This work evaluates associations between BMI and complications in surgery for acoustic neuroma (AN).

Study Design

Retrospective review.

Setting:

Two tertiary otology referral institutions.

Subjects and Methods

Patients undergoing surgery for AN. Univariate and multivariate analysis of association between BMI and complications was performed using two-tailed t tests and binary logistic regression.

Results

BMI ranged from 18.0 kg/m2 to 63.9 kg/m2 with mean of 29.2 kg/m2 among 362 included patients. High BMI was associated with increased risk of cerebrospinal fluid (CSF) leak ( p = 0.003) and need for revision surgery within 6 months ( p = 0.03). CSF leak occurred in 11.6% of obese patients (BMI ≥ 30.0) and 5.1% of patients with BMI < 30.0. There was no association between BMI and post-operative intracranial hemorrhage, wound infection, or incomplete resection ( p > 0.05). Multivariate analysis revealed BMI was associated with CSF leak (odds ratio 1.11 per BMI point, p = 0.002) and need for revision surgery (odds ratio 1.07 per BMI point, p = 0.02) independent of age, gender, tumor size, or surgical approach.

Conclusions

The largest series to date investigating BMI in acoustic surgery is presented. Elevated BMI is strongly associated with CSF leak and need for revision surgery but not with other complications. Obese or overweight patients undergoing acoustic neuroma resection should be counseled of their increased risk of CSF leak.

Overview of human obesity and central mechanisms regulating energy homeostasis

Obesity is now regarded as a global epidemic affecting both adults and children, and is associated with significant morbidity and mortality. Thus the effective management of obesity has become an important clinical focus. Therefore, an understanding of the pathways controlling appetite, satiety and food intake is critical for gaining an insight into the pathogenesis of obesity and also for the development of diagnostic tests and therapeutic agents for use in the clinical management of this condition. Over the last decade or more research using both mouse and human genetic models has elucidated the critical role of the leptin-melanocortin pathway in the hypothalamus, in regulating mammalian energy balance. In tandem with this, a clearer understanding of the regulation of gut-derived hormones and their interaction with the central nervous system has further illuminated the complex interplay between central and peripheral aspects of energy regulation. The obesity epidemic and the expanded knowledge base relating to its aetiopathogenesis have specific implications for clinical biochemistry. In particular, an increase in workload may be expected due to biochemical investigation of obesity and its co-morbidities. Moreover, advice on the in-depth investigation of complex cases of obesity may be sought, including information on newer diagnostic tests, such as serum leptin or molecular genetic analysis. There may also be a substantive role for chemical pathologists in establishing and running clinical obesity services. Finally, clinical biochemistry has a role in research pertaining to obesity and cardiometabolic risk.

Adiposity associated rise in leptin impairs ovarian activity during winter dormancy in Vespertilionid bat, Scotophilus heathi

The aim of the study was to evaluate the seasonal variation in serum leptin levels in a natural population of the female bat,Scotophilus heathiand their relationship to the changes in the body mass, serum insulin level, and ovarian activity. Circulating leptin level varied significantly over the season and correlated positively with the changes in body mass, and circulating insulin and androstenedione (A4) levels. Circulating leptin concentrations showed two peaks; one coincides with the maximum fat accumulation prior to winter dormancy, whereas the second shorter peak coincides with late pregnancy. Thein vivostudy inS. heathishowed that the increased circulating leptin level during winter dormancy coincides with the decreased expression of ovarian steroidogenic acute regulatory (StAR) protein, and low circulating estradiol (E2) level. At the same time, increased circulating leptin level coincides with increased expression of ovarian insulin receptor and high circulating A4 level. The low circulating leptin level during preovulatory period coincides with the increase in StAR protein but decrease in insulin receptor protein. Thein vitrostudy confirmed thein vivoobservations of inhibitory effect of leptin on LH induced StAR expression and E2production, whereas the stimulatory effect of leptin (high dose) on LH induced expression of insulin receptor protein and A4 production. However, pharmacological dose of leptin produced inhibitory effect on the expression of insulin receptor protein. The results of the present study thus suggest that high circulating leptin level during winter dormancy promotes adiposity and impairs ovarian activity by suppressing StAR-mediated E2production as well as by enhancing insulin receptor-mediated A4 synthesis thereby contributing anovulatory condition of delayed ovulation inS. heathi.

Assessment of cortisol and ACTH responses to the desmopressin test in patients with Cushing's syndrome and simple obesity

OBJECTIVE

The desmopressin test has recently been introduced in clinical practice as an adjunctive tool in the differential diagnosis of ACTH-dependent Cushing's syndrome (CS). It has been reported that the majority of patients with pituitary-dependent CS (Cushing's disease, CD) respond to desmopressin, while no such response is usually observed in other forms of this syndrome. In the present study, the responsiveness of the HPA axis to desmopressin was studied in a group of obese subjects. In addition, the ability of desmopressin administration to differentiate between patients with obesity and the various forms of Cushing's syndrome was investigated.

DESIGN AND SUBJECTS

Cortisol and ACTH responses to the administration of desmopressin (10 microg bolus i.v.) were examined in 20 consecutive patients with obesity (14 women and six men; BMI range: 34.5-66.7 kg/m2). Obese subjects had no clinical stigmata of CS. In all obese patients, either an overnight (dex 1 mg at 2300 h) (n = 8) or a formal low-dose (dex 0.5 mg 6-hourly for 2 days) (n = 12) dexamethasone suppression test was performed for the exclusion of Cushing's syndrome. Three of eight subjects showed failure of cortisol suppression (i.e. F > 28 nmol/l) to the overnight dexamethasone suppression test, but they had undetectable cortisol levels (< 28 nmol/l) on further testing with the formal 2-day test. All but two of the remaining subjects had undetectable cortisol levels (< 28 nmol/l) following the formal 2-day, low-dose, dexamethasone suppression test. For comparison, desmopressin responses were also tested in 33 patients with CS of varied aetiologies (25 patients with pituitary-dependent CS, three patients with occult ectopic ACTH secretion and five patients with primary adrenal CS). A positive response was considered to be an increment greater than 20% and 50% from baseline levels of cortisol and ACTH, respectively.

RESULTS

Mean cortisol (F) and ACTH levels did not differ from the baseline at any time point following desmopressin administration in the obese group (basal F: 417 +/- 41, peak F: 389 +/- 32 nmol/l, P > 0.05; basal ACTH: 33.5 +/- 4.3, peak ACTH: 50.6 +/- 16.6 ng/l, P > 0.05), or in patients with occult ectopic or primary adrenal CS. In contrast, in the group of patients with CD, there was a significant rise in the mean ACTH and F levels from baseline (basal F: 725 +/- 50, peak F: 1010 +/- 64 nmol/l, P < 0.01; basal ACTH: 88.6 +/- 11.8, peak ACTH: 351 +/- 64 ng/l, P < 0.01). Cortisol responses greater than 20% from baseline were observed in 21/25 (84%) patients with CD, but in only 3/20 (15%) of the obese patients. With regard to ACTH, increments greater than 50% over baseline were observed in 23/25 (92%) of patients with CD, and in only 3/20 (15%) of the obese patients. As previously reported, none of the patients with occult ectopic ACTH secretion or primary adrenal CS had a positive response.

CONCLUSIONS

The prevalence of subjects who met the criteria adopted to define positive cortisol and ACTH responses to the desmopressin test was significantly higher in the group of patients with Cushing's disease than in the group of patients with obesity. It is therefore suggested that this test may be occasionally useful in the differentiation between simple obesity and the pituitary-dependent form (but not other forms) of Cushing's syndrome.