Showing papers in "International Journal of Obesity in 1994"

Sexual dimorphism of age-related changes in whole-body fat distribution in the obese

Abstract: We performed a cross-sectional study using whole-body computerized tomographic (CT) scans in order to clarify age-related changes in whole-body fat distribution in both genders. The subjects were 66 men and 96 women, whose body mass index (BMI) was over 25 kg/m2. CT scans were performed at seven levels (head, fore-arms, upper arms, chest, abdomen, thighs and calves), and the fat volumes of the segments were calculated from the cross-sectional areas of the fat tissues. After calibrating to the total fat volumes, the relationship between age and the relative segmental fat volumes was analysed. In both genders, the relative intra-abdominal visceral fat volume increased and that of the legs decreased with age. The relative abdominal subcutaneous fat volume decreased with age only in male subjects. The increase in the relative visceral fat volume with age was about 2.6 times larger in males than in pre-menopausal females, while post-menopausal females showed the same increase as male subjects. These data suggest that there is a definite gender difference in the age-related changes in whole-body fat distribution, especially in the abdominal fat tissues. In addition, the accumulation of visceral fat is markedly accelerated by menopause in women.

Predictors of weight change over two years among a population of working adults - The Healthy Worker Project

Abstract: The present study examined behavioural predictors of body weight cross-sectionally and longitudinally in a cohort of 1639 male and 1913 female employees in 32 companies participating in a worksite intervention study for smoking cessation and weight control. Dietary intake, current and previous dieting behaviours, and physical activity were examined for their association with body weight over the two-year period. Cross-sectionally in both men and women, history of previous dieting, previous participation in a formal weight loss programme, current dieting and meat consumption were positively related to body weight while high intensity activity was negatively related to body weight. Prospectively, history of participation in a formal weight loss programme and dieting to lose weight at baseline, and increased consumption over time of french fries, dairy products, sweets and meat, independently predicted increases in body weight in women. Women who were dieting to lose weight or who had previously participated in a formal weight loss programme at baseline gained 1.99 lb and 1.74 lb more, respectively, than those who were not dieting to lose weight or who had not previously participated in a formal weight loss programme. Increased exercise, either walking or high intensity activity, predicted decreases in body weight in women (1.76 lb and 1.39 lb, respectively, for each session increase per week). In men, previous participation in a formal weight loss programme predicted increases in body weight over the two-year period. Men who had previously participated in a formal weight loss programme at baseline gained 4.83 lb more than those who had never previously participated in a formal weight loss programme. Increases in consumption of sweets and egg were prospectively related to increases in body weight, while increased walking and high intensity activity were related to decreases in body weight (0.86 lb and 3.54 lb, respectively, for each session increase per week). These results suggest the role that specific diet and exercise behaviours may play in body weight changes over time.

A multicompartment body composition technique based on computerized tomography.

Abstract: The objective of this study was to develop a body composition method based on computerized tomography (CT) which would make it possible to divide the body into multiple compartments at the tissue and organ level. Eight healthy males (21-42 years old) with BMIs ranging from 18.6 to 25.3 kg/m2 were used for the methodological development. Areas of tissues, organs and air/gas were measured in 28 cross-sectional scans having defined and identical positions in all examined subjects. The area determinations were performed with the following attenuation intervals (given in Hounsfield units, HU): air, gas and lungs: -1001 to -191 HU; adipose tissue (AT): -190 to -30 HU; all other soft tissues and organs: -29 to +151 HU; skeleton: 152 to 2500 HU. Various tissue and organ areas in the -29 to +151 HU interval were obtained by means of cursor circumscriptions, while area determinations in other intervals were based on the number of pixels fulfilling given attenuation criteria. Volumes of tissues, organs and gas were obtained from corresponding areas and the distances between the scans. The body was divided into 12 main volumes of tissues, organs and gas that could be further subdivided by region. The main volumes observed (in litres; mean +/- s.d.) were: skeleton (subdivisible into dense skeleton, red and yellow bone marrow): 8.7 +/- 0.9; skeletal muscle: 31.9 +/- 5.1; visceral AT (subdivisible into intra- and retroperitoneal, cardiac, other thoracic AT): 3.0 +/- 1.7; intra- and retroperitoneal organs other than AT: 4.6 +/- 0.8; gastrointestinal gas: 0.25 +/- 0.09; heart: 0.61 +/- 0.12; lungs and bronchial air: 5.1 +/- 1.1; other thoracic organs: 0.32 +/- 0.08; mammary glands: 0.001 +/- 0.004; CNS (subdivisible into brain and contents of spinal channel): 1.6 +/- 0.15; air in sinuses and trachea: 0.19 +/- 0.05; subcutaneous AT: 11.6 +/- 2.8; skin: 2.4 +/- 0.39. Precision errors as determined from double analyses of different tissue volumes ranged from 0.01 to 0.3 litres. For validation purposes, CT-estimated organ weights were obtained by multiplying organ volumes by their assumed densities. The sums of all organ weights were then compared with the measured body weights. The error calculated from the individual differences between these weights was 0.6 kg (0.85%). The multicompartmentation technique described has a high validity and reproducibility and is applicable over a wide range of medical fields which require body composition measurements at the tissue and organ level.

A weight on children's minds: body shape dissatisfactions at 9-years old.

Abstract: Although adolescent dieting is common, comparatively little is known about its developmental course. The present study investigated the self-perception and body shape satisfaction of 9-year old girls and boys in different weight categories. Two hundred and thirteen girls and 166 boys from three schools completed assessments of body-esteem, self-esteem, body shape preference and dietary restraint. The children's body weight and height were also measured. The heaviest children expressed the most discontent, having a low body-esteem, a desire for thinness and higher levels of dietary restraint. However, this desire for thinness and associated dieting motivation was apparent in some children in all weight categories. Furthermore, this pattern was more characteristic of girls than boys. By the age of nine, girls and boys already differ in their body shape satisfaction and differ in their body shape aspirations. Initiatives to reduce obesity should acknowledge these early and strongly-held gender differences or risk promoting the unwarranted pursuit of thinness by girls.

A 40-year history of overweight children in Stockholm: life-time overweight, morbidity, and mortality.

Abstract: We describe the 40-year weight history and adult morbidity and mortality in a cohort of 504 overweight children, aged 2 months to 16 years, who were admitted for investigation of their overweight to four children's hospitals in Stockholm between 1921 and 1947. Follow-up information was gathered by questionnaire at 10-year intervals, most recently in 1980-1983 (n = 458), on weight history (based on the body mass index (BMI = kg/m2)), as well as prevalence of cardiovascular disease (n = 143), diabetes (n = 39), and cancer (all types (n = 20)), reported during the 40 years of follow-up, and mortality from all causes (n = 55), determined from death certificate. The sample of overweight children remained overweight as adults; after age 55 years, the BMI began to decline for both genders. Female subjects were heavier than their male counterparts from postpuberty onward. Subjects who died by the 40-year follow-up and those reporting cardiovascular disease were significantly (P < or = 0.05) heavier at puberty and in adulthood than were healthier subjects. There was a marked increase in the BMI between postpuberty and age 25 among those who subsequently died, those who developed cardiovascular disease, and particularly among those who developed diabetes (P < or = 0.001). In contrast, those reporting cancer had a lower BMI throughout adulthood than those who did not. We conclude that overweight in adolescence may continue into adulthood and may be associated with subsequent adverse health outcomes.

Dietary composition and fat to sugar ratios in relation to obesity.

Abstract: The aim of this work was to investigate the relationship between dietary composition and prevalent overweight and obesity in a middle-aged Scottish population. An age and sex stratified cross-sectional study was carried out of coronary risk factors and diet. This was based on a personal health and food frequency questionnaire with a clinic attendance for body measurements which included weight and height. The subjects were 11,626 men and women aged 25-64 who participated in the baseline Scottish Heart Health and MONICA studies. Those reporting to be on slimming diets were excluded. The subjects were contacted via ten general practitioners surgeries from each of 22 Scottish districts (12 Mainland Health Boards) surveyed during 1984-1986. The following were measured: (1) the prevalence of overweight (BMI 25-28.6 for women and 25-30 for men) and obesity (BMI > 28.6 for women, and > 30 for men) according to intake fifths of carbohydrates (starch, total, extrinsic, intrinsic and milk sugars) and fat to carbohydrate ratios; (2) the percentage of the variance in BMI explained by multivariate analysis models which included each of the sugar variables and total energy intake. The overall prevalence of overweight and obesity in the Scottish population were 43 and 11% for men and 38 and 14% for women respectively. Their prevalence increased from the lowest to the highest fifth of Fat:ES intake, respectively for men and women, from 5 to 18.5% and from 13 to 26%. The prevalence of overweight and obesity declined from the lowest to the highest fifth of total carbohydrate, total (TS) and extrinsic (ES) sugar intake.(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective study of childbearing and 10-year weight gain in US white women 25 to 45 years of age.

Abstract: Although birth rates to US women aged 25 and older have increased markedly over the last two decades, accurate estimates of the long-term weight gain associated with childbearing are not available for older mothers in the general population. We examined the effect of childbearing on weight change in 2547 white women aged 25-45 years who were initially weighed in the First National Health and Nutrition Examination Survey (1971-75) and who were reweighed an average of 10 years later. Linear and logistic regression estimates were adjusted for duration of follow-up, age, body mass index, initial parity, education, smoking, drinking, employment status, marital status, illness, physical activity, and dieting to lose weight. Compared to parous women who did not give birth during the study period, the mean excess weight gain was 1.6 kg (95% Confidence Limits, +/- 2.3 kg) for nulliparous women, and was 1.7 kg (+/- 1.1 kg), 1.7 kg (+/- 2.0 kg), and 2.2 kg (+/- 4.3 kg), for women having one, two and three live births, respectively. Among women who were nulliparous at baseline, those that had their live births during the study period gained similar amounts of weight to that of women who began childbearing before the beginning of the study. The risk of gaining more than 13 kg was increased by 40%-60%, and the risk of becoming overweight was increased by 60%-110% in women having live births during the study. We conclude that the average weight gain associated with childbearing after the age of 25 is quite modest in US white women. However, for some women who give birth after the age of 25 the risks of major weight gain and becoming overweight are increased in association wtih childbearing.

Overweight cats: prevalence and risk factors

Abstract: Body condition was assessed by owners and veterinarians for over 2000 cats presented to 31 private veterinary hospitals in the Northeastern United States. Each owner completed a questionnaire querying potential factors associated with his/her cat's body condition. Veterinarians reported twenty-five percent of cats were overweight (heavy or obese), while owners estimated 29% of their pets were overweight. Apartment dwelling, inactivity, middle age, being male, neutered, of mixed breeding, and certain dietary factors were associated with being overweight.

DNA polymorphism in the uncoupling protein (UCP) gene and human body fat.

Abstract: The objective of this study was to identify DNA sequence variation in the UCP gene and to investigate its relationship with some obesity phenotypes. Two studies were carried out: (1) association study in unrelated subjects, and (2) sib-pair linkage analysis study in brothers and sisters. The subjects were 261 individuals from the Quebec Family Study (123 parents and 138 offsprings from 64 families). The following were measured: Body mass index, percent body fat (measured by hydrostatic weighing), and subcutaneous fat (estimated by the sum of 6 skinfolds) were measured in 1978-81 and again 12 years later. Resting metabolic rate (RMR) was measured only in 1989-93. Genetic analyses were performed using Southern blotting technique and a human UCP genomic probe. (1) A BcII restriction fragment length polymorphism was identified with two alleles of 8.3 and 4.5 kb in length, and respective frequencies of 0.28 and 0.72. (2) In unrelated adults from the parental generation, a cross-sectional analysis of the 1989-93 data showed no difference in body fat and RMR between the UCP genotypes. No significant difference for the absolute changes in body fat over the 12-year period among the UCP genotypes was observed. However, a higher frequency (P < 0.05) of the 8.3-kb allele was found in high gainers compared to low gainers (i.e., above and below the median value) for percent body fat over the 12-year period. (3) No evidence of linkage between any of the obesity phenotypes and the UCP BcII marker was found. For the first time, the presence of DNA polymorphism in the human UCP gene is reported. Although, no significant association and linkage were found between the UCP BcII gene marker and body fat in the cohort of the Quebec Family Study, a higher frequency of the 8.3-kb allele was found in individuals who gained more body fat over time.

Exercise-training enhances fat-free mass preservation during diet-induced weight loss: a meta-analytical finding.

Abstract: A meta-analysis was performed to examine how exercise training and gender influence the composition of diet-induced weight loss. The groups did not differ with respect to either the amount of body weight lost (mean = -10 +/- 1.4 kg) or fat mass lost (mean = -8 +/- 1.1 kg). However, exercise training significantly (P < 0.05) reduced the amount of body weight lost as fat-free mass compared to dietary restriction only (DO) for the same sex. The percentage of weight lost as fat-free mass for diet-plus-exercise (DPE) subjects was approximately half (P < 0.05) of that for DO subjects of the same sex (DO males = 28 +/- 4% of weight lost as fat-free mass; DPE males = 13 +/- 6%, DO females = 24 +/- 2%, DPE females = 11 +/- 3%). These data provide evidence that exercise training reduces the amount of body weight lost as fat-free mass during diet-induced weight loss. In addition, sex differences do not seem to exist with respect to the composition of diet-induced weight loss.

Fluoxetine : a randomized clinical trial in the treatment of obesity

Abstract: Fluoxetine hydrochloride (Lovan, Eli Lilly and Company, Indianapolis, Indiana, USA), a specific serotonin uptake inhibitor, was compared with placebo in 458 obese outpatients in a 52-week double-blind randomized ten-site trial to study its effect on weight reduction. Patients in the fluoxetine and placebo groups were predominantly Caucasian (81% and 85%, respectively) and female (81% and 79%, respectively), with a mean body mass index (BMI) of 36.2 and 35.8 kg/m2, respectively, and a mean age of 43 years (both groups). Fluoxetine therapy (60 mg/day) resulted in statistically significantly (P 40 kg/m2) attained and maintained a greater weight loss than patients with lower baseline BMIs (< 40 kg/m2). Two sites demonstrated greater efficacy than the study as a whole. The use of nutrition counselling at one site and behaviour modification at the other, or other site-to-site differences, may account for the improved efficacy. Fluoxetine was well tolerated and appeared to be safe therapy for the treatment of obesity with efficacy demonstrated for 28 weeks.

Peripheral and abdominal adiposity in childhood obesity.

Abstract: The aim of this work was to evaluate peripheral and abdominal adipose tissue (AT) content detected by MRI in normal weight and obese children, to compare MRI data with simple anthropometric indexes and to estimate intrabdominal adipose tissue (IAT) influence on cardiovascular risk factors. The subjects were 23 obese and 21 normal weight children aged 10 to 15 years. The following measurements were carried out: MRI analysis at lumbar level with definition of subcutaneous adipose tissue (SAT) area and IAT area; arm fat area (AFA); thigh fat area (TFA) and waist/hip ratio from anthropometry

Adipose tissue density, estimated adipose lipid fraction and whole body adiposity in male cadavers.

Abstract: Lipid and water together typically make up more than 90% of the body's adipose tissue mass. Although some reports have shown that the fraction of lipid in adipose tissue is greater in obese people than in lean ones, the quantitative relationship between adipose lipid fraction and overall adiposity of the body has never been investigated. We dissected six male unembalmed cadavers and weighed all adipose tissue (range 9.7-25.7 kg), allowing the calculation of percentage adiposity as 100 x total adipose mass/body mass (range 17.8-43.9%). Adipose tissue volume was determined by hydrostatic weighing of all portions of the dissected adipose tissue. For the six cadavers, whole body adipose tissue density ranged from 0.925-0.970 g/ml. Based on a three-component model of adipose tissue (lipid, water and dry fat-free solids), an expression for lipid fraction, F, was derived. After assuming densities for adipose lipid (0.905 g/ml), water at 36 degrees C (0.997 g/ml) and the dry fat-free component (1.38 g/ml), the equation simplified to F = 6.256/D-5.912, where D is adipose tissue density (g/ml). Lipid fraction was then calculated for each of the six cadavers: the range (0.54-0.85) was in excellent agreement with published data. There was a significant correlation (r = 0.95, P < 0.005) between calculated lipid fraction and percentage adiposity. The regression equation predicting lipid fraction from percentage adiposity was y = 0.327 + 0.0124x. We conclude that the estimated fraction of lipid in human adipose tissue shows both a wide range and a strong positive linear relationship with overall body fatness.

Body weight, fat distribution and the menopausal status in women. The VMH Collaborative Group.

Abstract: Since sex hormones are involved in the regulation of body composition and adipose tissue metabolism, in this study we investigated whether menopause may alter body weight and fat distribution in women. Data were obtained from the Virgilio-Menopause-Health Study, which is a longitudinal epidemiological project aimed at investigating the relationship between menopause and related plasma hormonal concentrations, body weight, fat distribution and health. Only data from the first cross-sectional examination are presented. Out of the 952 women living in the town of Virgilio, Mantua (Italy) and born between January 1st, 1932 and December 31st, 1946, 596 (62.6%) participated in the study. Since incomplete data were present in 19 women, 577 was the final sample size available for statistical analysis. The protocol included a collection of blood for hormones and biochemistry, a full clinical history with socioeconomic and personal information, drug use, smoking, dietary and physical activity habits, and several anthropometric measurements. According to the clinical and hormonal status, 160 women were classified as pre-menopausal, 124 as peri-menopausal and 293 as post-menopausal. After adjusting for age, we found that body mass index (BMI) was significantly higher in peri-menopausal than in pre-menopausal women and remained slightly, but again significantly, higher in post-menopausal women. Although waist-to-hip and waist-to-thigh ratios increased significantly and progressively from pre- to post-menopause, any difference was not significant after adjusting for age. Diet, physical activity and smoking habits did not explain the difference in BMI values. No difference was found in the use of estro-progestagen compounds between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Anthropometric or ultrasonic measurements in assessment of visceral fat? A comparative study.

Abstract: The main aim of the study (study 1) was to compare the accuracy of anthropometric and ultrasonic measurements in assessing the amount of visceral adipose tissue. An additional aim (study 2) was to verify ultrasound technique precision. Study 1: using computed tomography (CT) L4-L5 adipose tissue area as a gold standard we compared the accuracy of waist/hip circumference ratio, sagittal diameter and ultrasonic measurements of intra-abdominal depth in assessing the amount of visceral adipose tissue. Study 2: ultrasonic measurements of the intra-abdominal muscle-vertebra distance were made in triplicate by three different operators. In study 1, 24 volunteers were used; body mass index (BMI): 19-43. In study 2, 22 volunteers were used; BMI 20-42. In study 1, ultrasonic measurements of the abdominal depth correlated best with CT visceral adipose tissue area (r = 0.89 - 0.91). In study 2, inter-operator and intra-operator mean variation coefficients were about 7% and 5% respectively. We concluded that using a well standardized technique and properly trained operators, ultrasonic measurement of intra-abdominal depth is a valid method in assessing the amount of visceral adipose tissue.

Parental and perinatal factors associated with childhood obesity in north-east Italy.

Abstract: The association between obesity and perinatal, constitutional and social factors was studied in 1363 children (676 males, 687 females) living in six areas of north-east Italy. The children were randomly selected from four age categories (4,8,10 and 12 years of age). After adjustment for age, significant associations between the risk of obesity in the child and their body weight at birth (P < 0.01) and the father's or mother's body mass index (P < 0.001) were found in both genders. When these parental and perinatal variables were included as independent variables in a multiple logistic regression model controlling for the effect of age, parental body mass index and children's birth-weight remained independently associated with childhood obesity. In females, an interaction between birthweight and the mother's body mass index on the prevalence of obesity in childhood was found. In conclusion, parental obesity and birthweight represent major risk factors for obesity among children in north-east Italy.

A new technique for biopsy of human abdominal fat under local anaesthesia with Lidocaine.

Abstract: The objectives of this study were to develop a new technique to safety, reliably, and in a cosmetically acceptable way, obtain more than 5.0 g of abdominal subcutaneous fat in out-patients, and to investigate whether inhibitory effects of a local anaesthetic on adipose tissue function in vitro are sufficient argument against the use of infiltrative local anaesthesia during fat biopsy to obtain samples for metabolic studies. Measurements were obtained to compare glucose transport and lipolysis response to insulin in adipocytes isolated from subcutaneous abdominal fat obtained: (i) during elective surgery in eight women and four men (BMI 25.8 +/- 3.1 kg/m2); and (ii) from five male and three female out-patients (BMI 25.8 +/- 3.1 kg/m2) by the described novel technique performed under local anaesthesia with Lidocaine. The effects of acute and 11-day exposure to Lidocaine in vitro on adipocyte lipolysis and glucose transport response to insulin, and the growth potential were determined. In vivo exposure of the tissue samples to local anaesthetic by the novel technique had no apparent effect on isolated adipocyte responses to insulin by stimulation of glucose transport or by inhibitor- or adrenaline-stimulated lipolysis; the results were not different to those for adipocytes isolated from fat obtained during elective abdominal surgeries. Lidocaine added in vitro potently inhibited glucose transport and lipolysis in adipocytes, and cell attachment and growth in primary 'ceiling' culture; this effect persisted only as long as Lidocaine was present. After washing, adipocytes fully regained their function and growth regardless of the exposure period, as short as 30 min or as long as 11 days.(ABSTRACT TRUNCATED AT 250 WORDS)

The sagittal waist diameter and mortality in men: the Baltimore Longitudinal Study on Aging.

Abstract: The study objective was to determine the relationship between the abdominal sagittal diameter (waist depth) and subsequent mortality. This was a prospective study carried out in 981 male participants of the Baltimore Longitudinal Study on Aging which is a prospective study at the National Institute on Aging in Baltimore. The main outcome measures of the study were total and cause-specific mortality occurring during 17,529 person-years. The men were divided by age (cut-off point 55 years) at the start of follow-up. All-cause and coronary heart disease mortality rates (adjusted for age, height and body mass index) increased with increasing sagittal diameter in the younger group but not in the older group. No significant relationship was observed between the sagittal diameter and cancer mortality. Body mass index, skinfolds and waist/hip ratio were not significantly related to any of the endpoints studied. The increased risk of mortality with increasing sagittal diameter was somewhat stronger when the first ten years of follow-up were excluded and was more pronounced at lower levels of risk factors such as serum cholesterol, serum triglycerides, plasma glucose and diastolic blood pressure and in never plus ex-smokers compared to smokers. The study indicates that the abdominal sagittal diameter is a strong predictor of mortality in younger adult men independently of age, height, body mass index and conventional risk factors for mortality such as smoking, serum lipids and blood pressure. Regional adiposity may be a less strong risk factor for mortality in older men.

Dramatic increase in the prevalence of obesity in western Samoa over the 13 year period 1978-1991.

Abstract: Obesity and an increasing prevalence of associated conditions such as diabetes and cardiovascular disease are frequently observed in Pacific populations as lifestyles become more modernized. In 1978, a survey conducted in three geographically defined populations in Western Samoa showed large differences in the prevalence of obesity (body mass index (BMI) > or = 30 kg/m2) between rural and urban populations. A follow-up survey using similar methods was performed in 1991 to examine the current level of obesity in these three locations and to assess changes over time. Cross-sectional differences in the prevalence of obesity, mean BMI and waist-hip circumference ratio (WHR) between urban Apia and rural Poutasi and Tuasivi were examined after adjusting for age. There were higher levels of obesity in urban vs rural areas: 74% of women in Apia were obese compared with 62% in Poutasi and 56% in Tuasivi. In men, comparable figures were 57%, 44% and 36% for Apia, Poutasi and Tuasivi respectively. Mean BMIs followed the same pattern. By contrast, WHR varied little between locations. Even in subjects aged 25-34 years, more than 50% of women in all locations, and 45% of urban men were obese. Increasing physical activity in men, but not women, was associated with lower mean BMI. Increasing education level and job status were associated with increasing BMI but these relationships were significant only in men. Multivariate analysis showed age, location (urban), occupation (high status, women), and in men, physical inactivity, to be independently associated with increased risk of obesity. Prevalence of obesity increased dramatically between 1978 and 1991 in all locations, but especially in Tuasivi, where in males the increase was 297% and in females 115%. There was a rightward shift in the distribution of body mass index in both sexes and all locations. These extreme increases in the prevalence of obesity, even in young adults, over the relatively short 13-year study period suggest an increasing burden of chronic diseases facing Western Samoa in the future, and emphasize the need for effective intervention to bring about lifestyle modification.

Predictors of weight change in a bi-ethnic population. The San Antonio Heart Study.

Abstract: To study demographic, anthropometric and metabolic determinants of weight change, we divided a random sample of 1493 Mexican Americans and non-Hispanic whites into two groups: weight gainers and weight losers. This classification was based on the weight change during the eight-year follow-up of participants of the San Antonio Heart Study, a population-based longitudinal study of diabetes and cardiovascular disease. Men gained significantly less weight and lost more weight than women. The average gains for weight gainers were 6.1 kg and 6.8 kg for men and women respectively; and the average losses for weight losers were 4.4 and 3.4 kg for men and women respectively. There was no ethnic difference in either category of weight change. Weight gainers were significantly younger and leaner than weight losers. Fasting insulin was the only independent metabolic predictor of weight change and only among the most obese tertile of the population: the higher the baseline levels of fasting insulin, the less the likelihood of gaining and the greater the likelihood of losing weight. Our results support the hypothesis that insulin resistance is part of a negative feedback mechanism that attenuates further weight gain among the obese.

Transforming growth factor beta (TGF-beta) inhibits the differentiation of human adipocyte precursor cells in primary culture.

Abstract: In order to improve our understanding of the control of adipose tissue development in man by adipogenic and antiadipogenic factors we studied the effect of transforming growth factor beta (TGF beta) on the differentiation of human adipocyte precursor cells cultured in a serum-free medium. Addition of TGF beta at concentrations ranging from 5 to 100 pmol/l for 24 h at the beginning of the differentiation process resulted in a dose-dependent reduced expression of glycero-3-phosphate dehydrogenase (GPDH) activity. Continuous exposure of cells to TGF beta completely blocked differentiation even at a concentration of 5 pmol/l. Under these conditions cells were not able to accumulate lipid droplets. This inhibitory effect of TGF beta was not mediated by stimulation of cell proliferation. Exposure of newly developed fat cells to TGF beta was also associated with a significant suppression of GPDH activity. A 10-day incubation of cells with TGF beta reduced GPDH activity by more than 80% compared to controls. Despite this suppressive effect cells retained the typical fat cell-like morphology. In conclusion, these data clearly suggest that TGF beta exerts an inhibitory action on human adipose tissue development and reduces the activity of a lipogenic key enzyme in newly formed fat cells.

Concentrations of adipsin in blood and rates of adipsin secretion by adipose tissue in humans with normal, elevated and diminished adipose tissue mass

Abstract: Adipsin, which is identical to complement factor D, is synthesized by fat cells, circulates in the bloodstream and is profoundly deficient in mice with genetic and hypothalamic obesity. With the recent cloning of human adipsin, a quantitative human immunoassay has been developed. In the present study, we measured adipsin blood concentrations in humans with increased and decreased adipose stores as well as adipsin secretion by adipose tissue obtained from lean and obese individuals. The results demonstrate that adipsin is released by human adipose tissue fragments as has previously been shown in mice, and that, in contrast to obese mice, blood adipsin concentrations were not reduced in the obese humans tested in this study. We also observed that blood adipsin concentrations can vary as a function of feeding or adiposity, in that they tend to be mildly elevated in obese individuals or mildly reduced in individuals with total lipo-atrophy, cachexia related to AIDS and anorexia nervosa. Thus, the circulating concentration of adipsin tends to correlate positively with degree of adiposity. Clearly, no deficiency in blood adipsin concentrations or adipsin secretion by adipose tissue was observed in the obese individuals studied.

Prevalence of obesity among patients admitted for elective orthopaedic surgery.

Abstract: The aim of this work was to test the hypothesis that obesity is more common among patients requiring elective orthopaedic surgery than in the general population. A cross-sectional survey was carried out on 2673 consecutive patients admitted from the waiting list for four common types of operation: removal of lumbar intevertebral disc herniation, total hip replacement, elective knee arthroscopy or total knee replacement. Patients with primarily inflammatory joint disease were excluded. The immediate preoperative relative body weight, calculated as body mass index (BMI), of the patients was compared with data available on a general population sample of 44,034 people. Obesity was defined as BMI greater than the BMI + one standard deviation of the corresponding age and sex category of the general population. By these criteria, 256 patients (27%) with lumbar intervertebral disc herniation, 192 (24%) with total hip replacement, 135 (22%) with knee arthroscopy and 80 (27%) with knee replacement were obese, whereas the proportion in the general population was 16%. A major difference with the general population emerged in young patients of both sexes operated on for lumbar disc herniation and in women admitted for knee arthroscopy. The mean BMI of men aged 20 to 49 years subjected to knee arthroscopy did not differ from the general population. It was concluded that overweight people seem to be strongly over-represented among the patients requiring common orthopaedic surgical procedures.

The prevalence of obstructive sleep apnoea in an obese female population.

Abstract: Obstructive sleep apnoea (OSA) has been estimated to affect between 1 and 4% of the total population. OSA may be more frequent among women than studies based on subjects presenting for treatment would indicate. The aim of this study was to determine the prevalence of OSA in an obese female population (BMI > 30 kg/m2, age > 18 years) who presented to a hospital-based obesity clinic. The women were screened by an overnight ambulatory sleep study (MESAM) to detect OSA. Subjective sleep quality and sleep disturbance were assessed by a 19-item questionnaire, the Pittsburg sleep quality index (PSQI). From a population of 108 women, 29 were screened by MESAM. OSA was determined on the basis of respiratory disturbance index (RDI). The prevalence of OSA, defined as five or more respiratory disturbances per hour, was 37.9%. The mean age of the women was 43.6 +/- 2.57 years (mean +/- s.e.m.) and they had a mean BMI of 40.7 +/- 1.40 kg/m2. There was a significant positive correlation for RDI and BMI (r = 0.71; P < 0.001). Our findings indicate that over one third of women had OSA, yet they did not complain of symptoms even though the PSQI questionnaire indicated that they were poor sleepers. Non-specific symptomatology of OSA may be important diagnostically, particularly in women, and obese women should be considered at risk of OSA.

Physical activity training for weight loss in Latinas: a controlled trial

Abstract: This study tested the effects of an exercise and diet modification training program for weight loss among Latinas. Forty four obese women were assigned to an experimental training group (n = 22) or a control (n = 22), at random. One session per week for eight weeks included instruction for diet modification and walking for exercise, and all women were led in 20 min of walking during each session. Instruction was provided by a bi-cultural Spanish-speaking physician. Statistically significant (P < 0.05) decreases, relative to controls, were obtained for Body Mass Index, waist to hip ratio, and serum cholesterol. Significant increases were obtained for fitness, exercise rate and frequency, and diet/exercise knowledge. Results suggest that the training was effective for decreasing obesity and increasing fitness among Low SES, Mexican-American women. Implications for weight control and disease prevention among under-served populations are discussed.

Determinants of body mass index: a study from northern Italy.

Abstract: Overweight and obesity are associated with increased mortality and morbidity, and human weight is influenced by multiple factors, both genetically and environmentally determined. We investigated the influence of some socioeconomic, behavioral, dietary and reproductive factors on body mass index (BMI). Data were obtained from a comparison group of a case-control study of gastrointestinal cancers from the four largest teaching and general hospitals in Milan, northern Italy. The subjects were 1,188 men and 832 women admitted between January 1985 and June 1992 to the hospitals under study for diseases other than malignant or digestive and not known or suspected to be related to alcohol or tobacco. The following were measured: BMI (Quetelet's index, weight, kg/height, m2) and the corresponding standard errors (s.e.) in strata of selected variables, linear regression coefficients (beta) and correlation coefficients between BMI and each variable. Mean BMI increased with age until 35-44 years in men and 45-54 years in women. In both sexes BMI was inversely associated with education and social class. Smokers tended to be leaner than non-smokers, but no consistent trend was observed with increasing numbers of cigarettes. Alcohol drinkers had mean BMI similar to non-drinkers, except heavy drinking women who were lighter. BMI was not significantly associated with coffee, decaffeinated coffee, tea, bread, vegetable and fruit consumption. No relation was observed between total estimated caloric intake and BMI. In women BMI was directly associated with marriage and number of children, and inversely with oral contraceptive use.(ABSTRACT TRUNCATED AT 250 WORDS)

Obesity, school performance and behaviour of black, urban elementary school children

Abstract: Nutritional status, school performance and behaviour were assessed in a group of black, inner-city school children. Thirty-five per cent of the children were obese by triceps skinfold thickness criteria. The primary care taker's responses to the Child Behavior Checklist (CBCL) and the hyperactivity subscale of the Conners' Parent's Questionnaire indicated that the obese children were more likely to have abnormal scores. On the CBCL subscale scores, obese girls had a significantly higher 'sex problems' score. Although the other subscale scores were not significantly different, there was a significant trend for obese boys and girls to score higher on the CBCL subscale scores. In addition, the proportion of obese children placed in special education or remedial class settings was twice that for non-obese children. These results add to the limited information available concerning obese black children, and are consistent with previous findings suggesting subtle behaviour differences in obese children.

The relationships of abdominal obesity, hyperinsulinemia and saturated fat intake to serum lipid levels: the Normative Aging Study.

Abstract: Abdominal obesity and hyperinsulinemia are associated with abnormalities in lipid metabolism and are important risk factors for coronary artery disease. Because hyperinsulinemia frequently accompanies abdominal obesity, it is unclear whether each is independently related to lipid abnormalities. Dietary saturated fat may influence these associations since it is associated with elevated lipid levels, obesity and hyperinsulinemia. Abdominal obesity (indexed as abdomen-to-hip circumference ratio), serum insulin level and dietary saturated fat intake were examined in relation to serum levels of lipids and lipoproteins in 878 male participants of the Normative Aging Study. Abdomen-to-hip ratio and insulin level were inversely related to high density lipoprotein cholesterol (HDL-C) (r = -0.17 and -0.21, respectively), and positively related to triglycerides (r = 0.25 and 0.36, respectively). Saturated fat intake was positively related to body mass index (r = 0.20), abdomen-to-hip ratio (r = 0.13), and insulin level (r = 0.10). In multiple linear regression models, abdomen-to-hip ratio was positively related to triglycerides and low density lipoprotein cholesterol (LDL-C) after adjusting for the effects of body mass index, alcohol intake, age, cigarette smoking and physical activity level, but was not significantly related to HDL-C. When serum insulin level was included as a covariate, abdomen-to-hip ratio remained significantly related to LDL-C and triglycerides, although its relationship with triglycerides was attenuated. Insulin level remained inversely related to HDL-C and triglycerides in multivariate models which adjusted for the effects of abdomen-to-hip ratio and BMI.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of an ephedrine/caffeine combination and dexfenfluramine in the treatment of obesity. A double-blind multi-centre trial in general practice.

Abstract: In previous separate studies, dexfenfluramine (DF) and ephedrine/caffeine (EC) have been shown to promote weight loss in obese patients as compared with placebo. In order to compare the efficacy and safety of these two anorectic drugs, 103 patients with 20-80% overweight were included in a 15-week double-blind study in general practice. Patients were randomized to either 15 mg DF twice daily (n = 53), or 20 mg/200 mg ephedrine/caffeine three times a day (n = 50), supplementary to a 5 MJ/day diet. Forty-three patients from the DF group and 38 from the EC group completed the study. After 15 weeks of treatment, the DF group (n = 43) had lost 6.9 +/- 4.3 kg and the EC group (n = 38) had lost 8.3 +/- 5.2 kg (mean +/- s.d., P = 0.12). In the subgroup of patients with BMI > or = 30 kg/m2 (n = 59), the mean weight loss was 7.0 +/- 4.2 kg in the DF group (n = 29) and 9.0 +/- 5.3 kg in the EC group (n = 30), P < 0.05. Both systolic and diastolic blood pressures were reduced similarly during both treatments. Twenty-three patients in the DF group (43%) and 27 in the EC group (54%) complained of side-effects. Central nervous system side-effects, especially agitation, were more pronounced in the EC group (P < 0.05), whereas gastro-intestinal symptoms were more frequent in the DF group (P < 0.05). The side-effects declined markedly during the first month of treatment in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Can the increasing weight of Australians be explained by the decreasing prevalence of cigarette smoking

Abstract: In Australia there has been a recent increase in the body mass index (BMI) of the population and a decrease in smoking prevalence. Data from the three risk factor prevalence surveys conducted by the National Heart Foundation of Australia in 1980, 1983 and 1989 were analysed to determine if the increase in BMI could be explained by the decrease in smoking. For men in all age groups and for women aged 50 years or over, there were parallel increases in mean BMI for current smokers, ex-smokers and never smokers. For women under 50 years, the pattern of increasing BMI over time was less clear. Mean BMI increased over time within each five-year age group and in age 'cohorts' and the pattern was independent of smoking status. For men and for both groups of women there were similar changes in mean BMI over time for most categories of employment status, education and physical activity. Thus the increase in body weight cannot be explained by the decrease in smoking rate, or by the other factors investigated in this paper.