Adolescent body mass indices and self-perception

This study examined the relationship between body mass index (BMI) of adolescents and their perceived-weight status and self-concept, controlling for confounding factors. The data base was drawn from the High School and Beyond (HSB) study, which included 17,318 females and 15,878 males. BMI was calculated using self-reported weights and heights. Response variables included a self-concept index and evaluation of the statement "I am overweight." While respondents' perception of overweight status was accompanied by higher mean BMI values, there were discrepancies in perceived-weight and BMI-weight status. Logistic regression of explanatory variables on perception of overweight status revealed that BMI was the strongest predictor, gender was the second strongest, and the odds of perception of overweight status were higher for females than males by a factor of more than eight. Ordinary least squares regression of explanatory variables on the self-concept index revealed that perception of normal weight status, lower BMI, and male gender were strong predictors of positive self-concept. The findings indicate that substantial numbers of teenage females perceive themselves as overweight when BMI values suggest they are not, while males have a reasonably accurate weight perception.     

Fraction of carbon-free body mass as oxygen is a constant body composition ratio in men

Although elements are the foundation of the human body, information concerning the atomic level of body composition is still limited. The aim of this study was to explore potentially constant relationships among elements found in vivo. Based on the known stoichiometries of relevant chemical components, a theoretical model was derived, suggesting the existence of a relatively constant ratio of total body oxygen to carbon-free body mass (TBO/CFM) in men. Eight elements (C, H, N, Ca, P, K, Na and Cl ) were measured in 22 healthy male subjects by using in vivo neutron activation-40K whole-body counting, and TBO was calculated as the difference between body mass and the sum of the eight measured elements. TBO (in kg) was significantly correlated with CFM (in kg): TBO = 0.829 x CFM - 1.8; r = 0.998, P < 0.001, standard error of estimate = 0.4 kg. The ratio of TBO to CFM was relatively constant, mean +/- SD at 0. 800 +/- 0.009 with a CV of 1.1%. Oxygen and carbon are the two most abundant elements in the human body. The discovery of a constant relationship between oxygen and carbon is not only helpful for understanding the atomic level of body composition, but also provides the possibility of estimating the content of specific elements in vivo.     

Urinary creatinine excretion and lean body mass

In a group of 34 adult and child subjects a high correlation (r = 0.988) was found between lean body mass, as determined by potassium-40 counting, and urinary creatinine excretion. The effect of technical errors was reduced by averaging the results of two or three 40K assays on each subject, and by making consecutive 3-day collections of urine. It appears that one can make a reasonable estimate of lean body mass from urinary creatinine excretion.     

Inflammatory breast cancer and body mass index

PURPOSE: No studies have investigated the etiology of inflammatory breast cancer (IBC), the most lethal form of breast cancer. Because high body mass index (BMI) is associated with decreased risk of premenopausal breast cancer but increased risk of postmenopausal breast cancer, we evaluated whether high BMI was a risk factor for IBC. PATIENTS AND METHODS: In a case-comparison study, we matched by ethnicity and registration date 68 IBC patients treated at The University of Texas M.D. Anderson Cancer Center from 1985 to 1996 with 143 patients with non-IBC and 134 patients with cancer at sites other than the breast or reproductive tract (non-breast cancer). The non-breast cancer group was used in lieu of a population-based, healthy control group, which was not available. RESULTS: IBC patients were younger at menarche and the time of their first live birth than non-IBC and non-breast cancer patients. The proportion of premenopausal IBC patients was higher than the proportion of premenopausal women in the comparison groups, although differences were not significant. There were no differences in height, but IBC patients were heavier (77.6 kg) than non-IBC (70.0 kg) and non-breast cancer patients (68.0 kg). After adjusting for other factors, women in the highest BMI tertile (BMI > 26.65 kg/m2) relative to the lowest tertile (BMI < 22.27) had significantly increased IBC risk (IBC v non-IBC, odds ratio [OR] = 2.45, 95% confidence interval [CI] = 1.05 to 5.73; IBC v non-breast cancer, OR = 4.52, 95% CI = 1.85 to 11.04). This association was not significantly modified by menopausal status and was independent of age at menarche, family history of breast cancer, gravidity, smoking status, and alcohol use. CONCLUSION: Our investigation showed that high BMI was significantly associated with an increased risk of IBC. This association did not vary by menopausal status, although IBC patients were more likely to be premenopausal. Confirming our findings and identifying other IBC risk factors may provide directions for future research on the aggressive nature of IBC.     

Running economy: comparison of body mass adjustment methods

Iodine plays a central role in thyroid physiology, being both a major constituent of thyroid hormones (THS) and a regulator of thyroid gland function. This review concerns those aspects of thyroid physiology in which significant advances have been made in recent years. We have known for decades that the thyroid gland concentrates iodine (I-) against an electrochemical gradient by a carrier-mediated mechanism driven by ATP. A similar I- uptake mechanism is found in other organs, including salivary glands, stomach, choroid plexus, and mammary glands, but only in the thyroid does TSH regulate the process. This past year saw a major advance with the cloning of the thyroid I- transporter. This development opens the way to an elucidation of the regulation of I- transport in the normal gland and in thyroid neoplasms that lack this property ("cold" nodules). All of the subsequent steps in TH biosynthesis, from oxidation and organification of iodide to the secretion of T4 and T3 into the circulation, are stimulated by TSH and inhibited by excess iodine. Recently, some of the regulatory mechanisms have been clarified. The function of the major TH-binding proteins in plasma is to maintain an equilibrium between extracellular and cellular hormone pools. Transthyretin, the principal T4-binding protein in cerebrospinal fluid, may play a similar role in the central nervous system. Although it generally is agreed that cellular uptake of TH is a function of the unbound (free) form of the hormone, there is evidence that certain TH-binding plasma proteins (i.e., apolipoproteins) may serve specific transport functions. The intracellular concentration of T3, the active TH, is determined by the rates of cellular uptake of T4 and T3, the rates of metabolic transformation, including conversion of T4 to T3, and the rate of T3 efflux. The latter has been assumed to be a passive process. However, recent studies by our group in San Francisco have shown that T3 is transported out of cells by a specific, saturable, verapamil-inhibitable mechanism. This T3 efflux system is widespread among cells from many tissues, and, at least in liver, modulates intracellular and nuclear concentration of the hormone and thereby influences TH action.     

The Troms? Study: body height, body mass index and fractures

Tall persons suffer more hip fractures than shorter persons, and high body mass index is associated with fewer hip and forearm fractures. We have studied the association between body height, body mass index and all non-vertebral fractures in a large, prospective, population-based study. The middle-aged population of Troms?, Norway, was invited to surveys in 1979/80, 1986/87 and 1994/95 (The Troms? Study). Of 16,676 invited to the first two surveys, 12,270 attended both times (74%). Height and weight were measured without shoes at the surveys, and all non-vertebral fractures in the period 1988-1995 were registered (922 persons with fractures) and verified by radiography. The risk of a low-energy fracture was found to be positively associated with increasing body height and with decreasing body mass index. Furthermore, men who had gained weight had a lower risk of hip fractures, and women who had gained weight had a lower risk of fractures in the lower extremities. High body height is thus a risk factor for fractures, and 1 in 4 low-energy fractures among women today might be ascribed to the increase in average stature since the turn of the century. Low body mass index is associated with a higher risk of fractures, but the association is probably too weak to have any clinical relevance in this age category.     

Lean body mass as a determinant of thyroid size

A controlled study was performed in 18 viral cirrhosis patients to evaluate whether immune function, as indicated by natural killer (NK) cell activity, was improved by a branched-chain amino acid-enriched nutrient mixture (nutrient-mixture), Aminoleban EN. Five patients received the nutrient-mixture (100 g/day) for 2 to 6 weeks preceded by control periods. Five additional patients received the nutrient-mixture for 2 to 4 weeks, and the remaining 8 patients did not receive the nutrient-mixture. NK cell activity, CD16, CD8, CD11b, and amino acids were assayed before and after the administration of the drug in the nutrient-mixture-supplemented group, and two times with 1 to 6 month intervals in the control group. In the nutrient-mixture-supplemented group (n = 10), increasing NK cell activity, expressed as the ratio of values of post-treatment to that of baseline (ratio > 1.25) was detected in 7 (70%) patients, whereas in the control group (n = 13), it was detected in only 1 (7.7%) (p < 0.01). While in the affected group (NK cell activity ratio > 1.25, n = 7), all patients had compensated liver cirrhosis, in the unaffected group (NK cell activity ratio < 1.25, n = 3), 2 of 3 patients had decompensated liver cirrhosis (p < 0.02). Laboratory data, indicating severity of liver cirrhosis, such as total bilirubin and albumin, showed better values (p < 0.01, p < 0.05 respectively), and baseline NK cell activity was low (8.7 +/- 7.2% vs 33.3 +/- 13.0%, p < 0.05) in the affected group than unaffected group. NK cell subpopulations such as CD16 (%), CD11b (%) and one of the populations of T cell such as CD8 (%) showed no significant change throughout the study. As for amino acids analysis, Fischer's ratio was increased in the nutrient-mixture-supplemented group compared to the control group (p < 0.05), but none of the amino acids showed significant change. Thus the changes in NK cell activity were not explained by increase in NK cell subpopulations nor changes of amino acids. These results suggest that the branched-chain amino acid-enriched nutrient mixture increases NK cell activity moderately in patients who have compensated liver cirrhosis and shows lower values of baseline NK cell activity.     

Scaling of submaximal oxygen uptake with body mass and combined mass during uphill treadmill bicycling

This study examined the scaling relationships of net O2 uptake [V(O2)(net) = V(O2) - resting V(O2)] to body mass (MB) and combined mass (MC = MB + bicycle) during uphill treadmill bicycling. It was hypothesized that V(O2)(net) (l/min) would scale proportionally with MC [i.e., VO2(net) approximately M1.0C] and less than proportionally with MB [i.e., V(O2)(net) approximately MB]. Twenty-five competitive cyclists [73.9 +/- 8.8 and 85.0 +/- 9.0 (SD) kg for MB and MC, respectively] rode their bicycles on a treadmill at 3.46 m/s and grades of 1.7, 3.5, 5.2, and 7.0% while V(O2) was measured. Multiple log-linear regression procedures were applied to the pooled V(O2)(net) data to determine the exponents for MC and MB after statistically controlling for differences in treadmill grade and dynamic friction. The regression models were highly significant (R2 = 0.95, P < 0.001). Exponents for MC (0.99, 95% confidence interval = 0.80-1.18) and MB (0.89, 95% confidence interval = 0.72-1. 07) did not differ significantly from each other or 1.0. It was concluded that the 0.99 MC exponent was due to gravitational resistance, whereas the MB exponent was <1.0 because the bicycles were relatively lighter for heavier cyclists.     

Scaling of the limb long bones to body mass in terrestrial mammals

In their normal state, RPE cell are strongly adherent to Bruch's membrane. Certain pathological conditions such as retinal detachment cause an injury-type response (probably augmented or induced by the local accumulation of a variety of substances which modulate cell behaviour) in which RPE begin to dissociate from the membrane. This RPE-Bruch's membrane separation may be mediated by proteins with counter-adhesive properties and proteolytic enzymes, partly derived from the RPE themselves. Concomitant with the RPE disassociation, the cells begin to lose tertiary differentiation characteristics and gain macrophage-like features. When the "free" RPE arrive at the surface of the neuroretina, they may attach to or create a provisional matrix. Some of the cells adopt a fibroblast-like phenotype. This phenotype is similar to that of the dermal fibroblast during cutaneous wound repair and the fibroblastic RPE synthesise the types of matrix components found in healing skin wounds. Many of these molecules in turn further modulate the activities of the cells via several families of cell surface receptors, while the RPE continue to remodel the new matrix with a range of proteolytic enzymes. The resulting tissue (or membrane) has many of the features of a contractile scar and is the hallmark of the condition known as proliferative vitreoretinopathy (PVR). Thus the development of PVR, and the resulting tractional distortion of the neuroretina, appears to be dependent on RPE-matrix interactions. The interactions present a number of potential therapeutic targets for the management of the disorder.     

The economic costs associated with body mass index in a workplace

This study was undertaken to determine if a progressive correlation exists between body mass index (BMI), health care costs, and absenteeism and to identify an economically optimal BMI. We studied 3,066 First Chicago NBD employees by using health risk appraisals and personnel data. Analysis was completed for those employees with and without a risk for BMI. People at risk for BMI are more likely to have additional health risks, short-term disability and illness absence, and higher health care costs than those not at risk for BMI. A "J-shaped" curve between health care costs and BMI exists, with the low point occurring at about 25 to 27 kg/m2. We concluded that indirect and direct costs to an employer increase with increasing BMI. Employers may benefit from helping employees achieve a healthy weight. The initial target population should be those who are at highest risk of complications from obesity.     

Time perspective in socioeconomic inequalities in smoking and body mass index.

Objective: To determine if time perspective plays a mediating role in the relationship between socio-economic position (SEP) and both smoking and body mass index (BMI). Design: 2000 adults aged 18 years and over were randomly selected from the edited electoral register for the city of Newcastle upon Tyne, England and sent a postal questionnaire. Two reminders were sent. Main outcome measures: Socio-economic position was measured using the Index of Multiple Deprivation (IMD) of the area of residence. Time perspective was measured using the Consideration of Future Consequences Scale (CFCS). Smoking and BMI were self-reported. Results: Full data was available for 804 individuals (response rate: 40.2%). After controlling for age, gender and health status, IMD was significantly associated with BMI, smoking status and CFCS score (p     

Spine and spinal cord war injuries during the war in Croatia

OBJECTIVE: The present report summarizes the experience of an evacuation hospital in southern Croatia in treating 96 patients with spine and spinal cord war injuries. METHODS: A retrospective review was done for 96 wounded persons (86 soldiers, 10 civilians) with spinal cord injuries from August 1991 through December 1995. The ages ranged from 15 to 59 years (mean, 28.3 years for soldiers, 38.5 years for civilians). Diagnostic procedures were plain radiography, computed tomography, and computed tomographic myelography. However, in most cases a more conservative surgical approach was used. RESULTS: The highest rates of admittance were recorded in 1992 (N = 38) and 1993 (N = 47). The lumbar spine was injured in 55% of the patients, the cervical and thoracic spines in 17.7%. All injuries were caused by projectiles from automatic rifles and sniper fire (51%) and from fragments of explosive devices (49%). Blast injury of the spinal cord was found in 10 patients. The most frequent complications caused by the fragments were wound infection, urinary tract infection, decubitus, and pneumonia. Four patients (4.2%) died in the hospital, and 43.0% of patients survived but were severely handicapped. CONCLUSION: Careful clinical examination combined with modern diagnostic imaging and use of broad-spectrum antibiotics reduced the need for surgical intervention in patients with spinal cord injuries.     

Induction of Galphaq-specific antisense RNA in vivo causes increased body mass and hyperadiposity

Transgenic BDF-1 mice harboring an inducible, tissue-specific transgene for RNA antisense to Galphaq provide a model in which to study a loss-of-function mutant of Galphaq in vivo. Galphaq deficiency induced in liver and white adipose tissue at birth produced increased body mass and hyperadiposity within 5 weeks of birth that persisted throughout adult life. Galphaq-deficient adipocytes display reduced lipolytic responses, shown to reflect a newly discovered, alpha1-adrenergic regulation of lipolysis. This alpha1-adrenergic response via phosphoinositide hydrolysis and activation of protein kinase C is lacking in the Galphaq loss-of-function mutants in vivo and provides a basis for the increased fat accumulation.     

Anabolic agents in trauma and sepsis: repleting body mass and function

Both growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are potent anabolic agents. Exogenous GH improves nitrogen metabolism in patients undergoing surgery; however, the anabolic effects of GH in cases of multiple injury, burn, and sepsis are equivocal. Moreover, few data are available concerning the effects of GH in organ failures. Exogenous IGF-1 attenuates catabolism in animal trauma models. A clinical trial, however, did not confirm the anabolic actions of IGF-1. Further knowledge of the interaction between the GH/IGF-1 axis in critical illness is essential for GH and IGF-1 therapy. Theoretically, the improved nitrogen metabolism achieved with exogenous anabolic agents may provide functional benefits. However, only a few studies have confirmed the beneficial effects of GH on body function in trauma and sepsis. GH treatment decreases the postoperative depression of hand grip strength. GH also stimulates wound healing. Both GH and IGF-1 exert their effects on immune system, suggesting that these anabolic agents are potentially beneficial for the prevention and treatment of sepsis. On the contrary, inhibition of polymorphonuclear neutrophil apoptosis and the potentiation of PMNs by GH may have harmful effects on the systemic responses. Further studies are required to determine the safety and clinical benefits of GH administration in critical illness.     

Leg mass and lower body negative pressure tolerance in men and women

To explore the hypothesis that lower body muscle mass correlates with orthostatic tolerance, 18 healthy volunteers (age 18-48 yr; 10 men, 8 women) underwent a graded lower body negative pressure (LBNP) protocol consisting of six, 5-min stages of suction up to 60 mmHg in 10-mmHg increments. Forearm blood flow, heart rate, and blood pressure were measured, and forearm vascular resistance was calculated. Leg muscle mass was assessed by dual-energy X-ray absorptiometry. All subjects received standard intravenous hydration for at least 8 h before the study. Six men and four women completed all stages of LBNP. Four men and four women developed presyncopal symptoms, including marked bradycardia and/or hypotension, at LBNP levels of 30 mmHg (n = 2;1 man, 1 woman), 40 mmHg (n = 2;1 man, 1 woman), and 50 mmHg (n = 4;2 men, 2 women). The presyncopal subjects had leg muscle masses ranging from 19.5 to 25.2 kg in men and from 11.7 to 16.6 kg in women. In subjects who completed all stages of LBNP, leg muscle mass ranged from 17.5 to 24.1 kg in men and from 10.4 to 18.0 kg in women. Leg muscle mass did not differ between presyncopal subjects and those who completed the protocol. Furthermore, there were no differences in the hemodynamic responses to LBNP between subjects with low vs. high leg mass. These data suggest that leg muscle mass is not a critical determinant of LBNP tolerance in otherwise healthy men and women.     

Evaluation by bioelectric impedance of body fluid compartments and body mass in cardiosurgical patients before and after total cardiopulmonary bypass

BACKGROUND: To evaluate the influence of extracorporeal circulation (ECC) on fluid compartments and body mass using impedance measurements. METHODS: A prospective study was performed in 20 consecutive patients undergoing ECC during heart surgery at the Department of Heart Surgery of Verona Hospital. Resistance or reactance measurements at 1-5-10-50-100 KHz were performed in 20 patients undergoing heart surgery for valvular or coronary pathologies in class NYHA I or II, preoperatively and on day 1, 3 and 6 in order to evaluate total body water (TBW), intracellular water (ICW), extracellular water (ECW), thin and fat body mass. Weight, fluid-electrolytic balance and hematochemical parameters relating to electrochemical phenomena and the distribution of volumes in the various compartments, namely sodium, potassium and plasmatic osmolarity, were measured at the same times. Comparisons were made both between the data and during ECC. RESULTS: It was found that there was a mean postoperative weight gain of 2 kg in terms of total body water. Subsequently, this finding tended to decrease to basal values by day 6. Immediately after ECC, the water gain appeared to be predominantly extracellular, whereas the intracellular increase peaked on day 1. The change in total body water was correlated with the weight and fluid balance, but electrical measurements showed values above the corresponding weight gain. The duration of ECC was significantly correlated with bioelectric parameters, but not with absolute weight values. CONCLUSIONS: The method proved useful for the purpose, especially with regard to the overall population examined rather than individual patients. The dual-compartment electric model appears to be more suitable than the single-compartment model for exploring the different compartments. The trend of weight and total body water, which were correlated in pattern but not in absolute values, may be interpreted as a redistribution of fluids, also suggested by changes in electric parameters relating to compartmental distribution.