Effect of Regain of Body Weight on Regional Body Fat Distribution: Comparison Between Pre- and Postmenopausal Obese Women

The aim of our study was to determine if regain of body weight increases visceral fat in obese women and if regain of weight has a different effect upon pre- and postmenopausal women. Twenty obese women (11 pre- and 9 postmenopausal) underwent a very low energy diet (VLED) for 2 weeks to lose weight. They then regained body weight in spite of the recommended hypocaloric diet. No significant modifications in body fat distribution indexes were found by computed tomography between VLED and after regain of weight. No significant changes were found in metabolic variables. No interactions between menopausal status and regain of body weight were observed. In conclusion, regain of weight does not seem to cause an increase in visceral fat; both pre- and postmenopausal women showed the same body fat distribution before weight loss and after regain of weight.     

Relationship among Habitual Tea Consumption,Percent Body Fat,and Body Fat Distribution

Objective: To disclose the possible relationship between habitual tea consumption and changes in total body fat and fat distribution in humans. Research Methods and Procedures: A cross‐sectional survey of 1210 epidemiologically sampled adults (569 men and 641 women) were enrolled in our study. Tea consumption and other lifestyle characteristics were obtained by structured questionnaires. Percent body fat (BF%) was measured using bioelectrical impedance analysis. Body fat distribution was assessed using waist‐to‐hip ratio (WHR). Results: Among the 1103 analyzed subjects, 473 adults (42.9%) consumed tea once or more per week for at least 6 months. The habitual tea drinkers were male‐dominant, more frequently current smokers, and alcohol or coffee drinkers than the nonhabitual tea drinkers. Habitual tea drinkers for more than 10 years showed a 19.6% reduction in BF% and a 2.1% reduction in WHR compared with nonhabitual tea drinkers. The multiple stepwise regression models revealed that men, older age, higher BMI, and current smokers were positive factors for BF% and WHR. In contrast, longer duration of habitual tea consumption and higher total physical activity were negative factors for BF%. Longer duration of habitual tea consumption, higher socioeconomic status, and premenopausal status were negative factors for WHR. Discussion: An inverse relationship may exist among habitual tea consumption, BF%, and body fat distribution, especially for subjects who have maintained the habit of tea consumption for more than 10 years.     

Associations of Body Mass and Body Fat Distribution with Parity Among African-American and Caucasian Women: The CARDIA Study

Associations of parity with body fat and its distribution are poorly understood; therefore, we examined the relationships between parity and obesity in young adult women. Body mass index (BMI), skin folds, and waist-hip ratio were compared in 1452 African-American and 1268 Caucasian nonpregnant women aged 18 to 30, adjusting for age (where no age-parity interactions were present), education, physical activity (assessed by questionnaire) and fitness (assessed by graded exercise test), dietary fat intake, alcohol and smoking. Adjusted mean BMI was significantly higher in African-American women aged 25–30 years with three or more children (28.5 kg/m²) than in those with two (27.0 kg/m²), one (26.2 kg/m²), or no children (26.3 kg/m²). Similar trends were found in Caucasians (BMI = 23.3, 23.4, 23.7, 25.0 kg/m² for parity = 0,1, 2, ≥ 3, respectively), but the mean BMI was significantly higher in African Americans in each parity group. The association between BMI and parity was not present among women 18–24 years of age. Skinfolds were directly associated with parity in African Americans only. Waist-hip ratios were generally lower among nulliparous than parous women in both ethnic groups; race differences were present only among nulliparas. In conclusion, parity was associated with BMI in women aged 25 to 30 years but did not explain ethnicity-related differences in body mass.     

Birth weight is inversely associated with central adipose tissue in healthy children and adolescents

Objective: Previous studies have explored the association between birth weight and excess childhood body fat, but few have used precise measures of body composition, leading to equivocal and sometimes contradictory results. Research Methods and Procedures: Subjects included 101 children who underwent DXA measurements between 1995 and 2000. Birth weight and gestational age were assessed using maternal recall. Multiple linear regression analysis was used to determine the relationship between birth weight and the following four outcome variables: total fat mass (FM), truncal fat mass (TrFM), percentage body fat (%BF), and TrFM adjusted for FM (TrFMadj), controlling for current weight and Tanner stage. Results: The mean age of the children studied was 12.9 ± 2.4 years, and the mean birth weight reported by subjects’ mothers was 3.3 ± 0.5 kg. The FM and TrFM were 12.8 ± 8.7 kg and 5.1 ± 4.1 kg, respectively, and the mean %BF was 22.9 ± 10.3%. Birth weight was a significant predictor of FM (p = 0.02) and %BF (p = 0.038). However, birth weight adjusted for gestational age (BWTadj) was a significant (p = 0.03) negative predictor of TrFMadj, independently of race, sex, Tanner stage, and current weight. Discussion: These results provide evidence that, even in childhood and adolescence, a higher birth weight is associated with higher FM and %BF, while a low birth weight is associated with TrFM, adjusted for FM.     

Relationships between Dietary Fat,Body Fat,and Serum Lipid Profile in Prepubertal Children

KU, CHING YI, BARBARA A. GOWER, TIM R. NAGY, MICHAEL I. GORAN. Relationships between dietary fat, body fat, and serum lipid profile in prepubertal children. Obes Res. 1998;6:400–407. Objective : The purpose of the study was to test the hypothesis that dietary fat components were associated with the serum lipid profile independent of ethnicity, body fat, and fat distribution in prepubertal children. Research Methods and Procedures : Sixty-six children (45 African American and 21 Caucasian), aged from 4 to 10 years, were recruited into the study. Dietary total fat, saturated fat, monounsaturated fat, and polyunsaturated fat were estimated by averaging two 24-hour diet recalls. Fasting serum triacylglycerol, total cholesterol, and high-density lipoprotein cholesterol were analyzed, and low-density lipoprotein cholesterol (LDL-C) was calculated by the method of Friedewald. Body composition and fat distribution were measured by dual energy X-ray absorptiometry and computed tomography. Results : Children in both ethnic groups tended to overreport their dietary intake relative to total energy expenditure by 18%. African American children consumed more energy from total fat (35.3% vs. 31.5%, p<0.05), saturated fat (13.7% vs 12.2%, p<0.05), protein (16.4% vs. 13.2%, p = 0.02), and less from carbohydrate (48% vs. 57.1%, p<0.01) than Caucasian children. There was no significant correlation between dietary fat and either serum lipids or body fat indices after adjusting for nonfat energy intake and total lean tissue mass. Total body fat (r = 0.32), subcutaneous abdominal adipose tissue (r = 0.39), and intraabdominal adipose tissue (r = 0.42) were positively related to serum triacylglycerol; these associations remained significant in a multiple linear regression model in which body fat indices were adjusted for ethnicity, total lean tissue, dietary total fat, and nonfat intake. Discussion : Our results do not support a link between dietary fat and serum lipids; instead, our data suggest that body fat may play a more important role than dietary fat in the course of cardiovascular disease development in prepubertal children.     

Genetic and Environmental Influences on the Tracking of Body Size from Birth to Early Adulthood

Objective: This study identified genetic and environmental influences on the tracking of body size from birth to 16 to 18.5 years of age. Research Methods and Procedures: Longitudinal information was collected from a nationally representative sample of Finnish twin adolescents (birth cohorts 1975 to 1979) and their parents through questionnaires mailed when the twins were ages 16 and 18.5 years old. The sample included 702 monozygotic, 724 same‐sex dizygotic, and 762 opposite‐sex dizygotic sets of twins. The measures used were length, weight, ponderal index (kilograms per cubic meters), and gestational age at birth, and height, weight, and body mass index (kilograms per square meters) at 16 to 18.5 years of age. The changes in genetic and environmental influences on body size from birth to early adulthood were analyzed by quantitative genetic modeling. Results: The twins who had a higher weight or ponderal index at birth were taller and heavier in early adulthood, whereas those who were longer at birth were taller, but not heavier, later in life. Adult height was affected more by the birth size than body mass index. In the genetic modeling analyses, the genetic factors accounting for the variation of body size became more apparent with age, and both genetic and environmental influences on stature had a sizable carry‐over effect from birth to late adolescence, whereas for relative weight, the influences were more age‐specific. Discussion: The genetic and environmental architecture of body size changes from birth to adulthood. Even in monozygotic twins who share their genetic background, the initially larger twin tended to remain larger, demonstrating the long‐lasting effects of fetal environment on final body size.     

Human Body Composition and the Epidemiology of Chronic Disease

Obesity and body fat distribution (FD) are established risk factors for chronic diseases. The body mass index (BMI) and the waist/hip circumference ratio (WHR) are used conventionally as indices of obesity and FD in epidemiological studies. Although some general limitations of these indices are recognized, others that affect their use in relative risks for disease are not well recognized. These include effects of sex, ethnicity, and especially age on the relationships between these indices and body composition, which can result in substantial misclassification of obesity and FD. There is considerable variability in body composition for any BMI, and some individuals with low BMIs have as much fat as those with high BMIs. This results in poor sensitivity for classifying levels of body fatness (e.g., too many “false negatives,” or overweight individuals classified as not overweight), and relative risks are attenuated across all categories of BMI. A more serious problem, however, is that at different ages the same levels of BMI correspond to different amounts of fat and fat-free mass. Data from the Rosetta Study and the New Mexico Aging Process Study show that older adults have, on average, more fat than younger adults at any BMI, due to the loss of muscle mass with age. As a result, the sensitivity of BMI cutpoints with respect to body fatness decreases with age, and the use of a fixed cutpoint for all ages results in “differential mis-classification bias.” Taken together, these issues sug- gest that the increases with age in the prevalences of overweight and obesity, and in the risks for chronic diseases, may be mis-estimated using BMI. Similar issues may affect the use of WHR for estimating prevalences and associated risks of FD. New field methods for estimating body composition are available that can be applied in large, epidemiologic follow-up studies of chronic diseases. These methods will allow epidemiologists to consider, for example, whether it is increased fat, or the replacement of fat-free mass with fat, with age that is associated with risk for chronic disease.     

Birth Weight,Adulthood BMI,and Subsequent Weight Gain in Relation to Leptin Levels in Swedish Women

LISSNER, LAUREN, CECILIA KARLSSON, ANNA KARIN LINDROOS, LARS SJOSTROM, BJORN CARLSSON, LENA CARLSSON, AND CALLE BENGTSSON. Birth weight, adulthood BMI, and subsequent weight gain in relation to leptin levels in Swedish women. Obes Res. Objective Leptin seems to be involved in the regulation of energy balance, although little is known about the epidemiology of leptin with respect to prediction of weight gain and incidence of obesity-related diseases. The dual aim of this study is to document characteristics of leptin after long-term storage, and to describe its relation to body weight, from birth to old age, in an ongoing prospective study. Research Methods and Procedures A population-based sample of Swedish women was first examined at the ages of 38 to 60 and re-examined 24 years later. This study used 1358 frozen serum samples that had been stored 29 years for analysis of leptin concentrations and their relation to body weight history. Results Leptin values obtained from stored samples showed the same correlation with relative weight as that seen in a contemporary sample with similar demographic characteristics. Lower self-reported birth weight was associated with higher leptin levels in adulthood (p = 0.01), controlling for age and adult BMI. Prospective analyses revealed that high leptin in 38 to 46-year-olds predicted subsequent long-term weight gain (p = 0.003), although no significant associations were seen in women initially aged 50 or older. Discussion: It is feasible to use frozen serum for studying leptin in relation to obesity and related developments many years later. High leptin level was a risk factor for subsequent weight gain in 38- and 46-year-old women. Retrospective analyses involving birth weight suggest that leptin resistance in adulthood might have fetal origins.     

Visceral Adipose Tissue in Women: Longitudinal Study of the Effects of Fat Gain,Time, and Race

Objective: To determine the effects of fat gain, time, and race on the accumulation of visceral adipose tissue (VAT) in a group of normal‐weight premenopausal women. Research Methods and Procedures: Sixty‐five women participated in the study (32 African American and 33 white). The mean age of subjects was 34 ± 6 years (range, 22 to 47 years). Eligible subjects were women who had body mass indices <25 kg/m² at baseline and who had completed evaluations at baseline and at follow‐up year 1, without intervention. A subset of subjects was reevaluated annually for up to 4 years. Body composition was assessed by DXA, and VAT was determined from a single computed tomography scan. A linear mixed model was used to examine changes in VAT over time, with total body fat as a covariate Results: Total fat mass was not significantly different between races at baseline and increased significantly in both groups over time (p < 0.001). Time‐related increases in total body fat were greater in African‐American women (p < 0.01). VAT was significantly higher in white women at baseline (p < 0.01) and increased significantly over time in both races (p < 0.01), but remained higher in white women (p < 0.001). Increases in VAT, relative to total body fat, were greater than the increases in total body fat over time, independent of age and race (p < 0.001). Discussion: Gaining total body‐fat mass results in a higher increase in VAT, relative to total body fat, regardless of race and age, although African‐American women maintain a lower VAT levels across time.     

Growth of Visceral Fat,Subcutaneous Abdominal Fat,and Total Body Fat in Children

Objective: To examine the patterns of growth of visceral fat, subcutaneous abdominal fat, and total body fat over a 3‐ to 5‐year period in white and African American children. Research Methods and Procedures: Children (mean age: 8.1 ± 1.6 years at baseline) were recruited from Birmingham, Alabama, and those with three or more repeated annual measurements were included in the analysis (N = 138 children and 601 observations). Abdominal adipose tissue (visceral and subcutaneous) was measured using computed tomography. Total body fat and lean tissue mass were measured by DXA. Random growth curve modeling was performed to estimate growth rates of the different body fat compartments. Results: Visceral fat and total body fat both exhibited significant growth effects before and after adjusting for subcutaneous abdominal fat and lean tissue mass, respectively, and for gender, race, and baseline age (5.2 ± 2.2 cm²/yr and 1.9 ± 0.8 kg/yr, respectively). After adjusting for total body fat, the growth of subcutaneous abdominal fat was not significant. Whites showed a higher visceral fat growth than did African Americans (difference: 1.9 ± 0.8 cm²/yr), but there was no ethnic difference for growth of subcutaneous abdominal fat or total body fat. There were no gender differences found for any of the growth rates. Discussion: Growth of visceral fat remained significant after adjusting for growth of subcutaneous abdominal fat, implying that the acquisition of the two abdominal fat compartments may involve different physiologic mechanisms. In contrast, growth of subcutaneous abdominal fat was explained by growth in total body fat, suggesting that subcutaneous fat may not be preferentially deposited in the abdominal area during this phase of growth. Finally, significantly higher growth of visceral fat in white compared with African American children is consistent with cross‐sectional findings.     

Gender Differences in Changes in Subcutaneous and Intra-abdominal Fat during Weight Reduction: An Ultrasound Study

WIRTH, ALFRED, AND BERIT STEINMETZ. Gender differences in changes in subcutaneous and intra-abdominal fat during weight reduction: an ultrasound study. Obes Res. 1998;6:393–399. Objective : In weight-reducing programs, men usually display greater improvement in metabolic risk factors than women. This gender difference may be related to enhanced weight and fat loss due to a greater energy deficit in men. To clarify the relationship between changes in metabolic profile, body fat composition, and weight loss, both sexes were studied under a regimen in which similar amounts of weight were lost. Research Methods and Procedures : A cross-sectional study using anthropometric (body mass index and waist-to-hip ratio), impedance (bioelectrical impedance analysis) and ultrasound measurement methods (thickness of subcutaneous fat layers, intra-abdominal sagittal diameter) were conducted. The metabolic risk profile was determined by measuring lipids, lipoproteins, and blood pressure. The weight loss program lasted 15 weeks: 3 weeks under controlled conditions in the hospital and 12 weeks on an ambulatory basis. Patients were instructed to follow a mixed diet. Calorie intake was restricted to 1500 kcal/day for the men and 1200 kcal/day for the women. Thirty-two subjects with obesity (16 men and 16 women), with a mean body mass index of 35 kg/m²—matched with regard to age, height, and body weight—took part in the study. Results : As expected, weight loss was similar for both sexes (?13.4 kg vs. ?12.8 kg). Also, body fat mass changed to the same extent in absolute and relative terms. The waist-to-hip ratio was identical before and after treatment in both sexes. The men lost more visceral fat than the women. This result is based on changes in intra-abdominal diameter as well as abdominal subcutaneous fat in relation to waist circumference. Changes in abdominal diameter were paralleled by reductions in triglycerides and increases in high-density lipoprotein-cholesterol. Subcutaneous fat loss was more pronounced in women than in men. Discussion : Where absolute and relative reductions in body weight and body fat are similar, men mobilize more intraabdominal fat than women, whereas women lose more subcutaneous fat. The greater reduction in intra-abdominal fat seen in men is accompanied by a more pronounced improvement in the metabolic risk profile. Therefore, greater improvement of risk factors in men is not only related to a greater negative energy balance, as shown in most studies, but is also sex-specific.     

Predicting Total Body Fat from Anthropometry in Latino Children

Objective: To develop prediction equations for total body fat specific to Latino children, using demographic and anthropometric measures. Research Methods and Procedures: Ninety‐six Latino children (7 to 13 years old) were studied. Two‐thirds of the sample was randomized into the equation development group; the remainder served as the cross‐validation group. Total body fat was measured by DXA. Measures included weight, height, waist and hip circumferences, and skinfolds (suprailiac, triceps, abdomen, subscapula, thigh, and calf). Results: The previously published equation from Dezenberg et al. did not accurately predict total body fat in Latino children. However, newly developed equations with either body weight alone (intercept ± SE = 1.78 ± 1.53 kg, p > 0.05; slope ± SE = 0.90 ± 0.07, p > 0.05 against slope = 1.0; R² = 0.86), weight plus age and gender (intercept ± SE = 2.28 ± 1.20 kg, p > 0.05; slope ± SE = 0.91 ± 0.05, p > 0.05; against slope = 1.0; R² = 0.92), or weight plus height, gender, Tanner stage, and abdominal skinfold (intercept ± SE = 1.47 ± 1.01 kg, p > 0.05; slope ± SE = 0.93 ± 0.04, p > 0.05; against slope = 1.0, R² = 0.97) predicted total body fat without bias. Discussion: Unique prediction equations of total body fat may be needed for Latino children. Weight, as the single most significant predictor, can be used easily to estimate total body fat in the absence of any additional measures. Including age and gender with weight produces an equally stable prediction equation with increasing precision. Using a combination of demographic and anthropometric measures, we were able to capture 97% of the variance in measured total body fat.     

Effect of Changes in Fat Distribution on the Rates of Change of Insulin Response in Children

Objective: To develop mixed models for examining longitudinal associations between rates of change in visceral, subcutaneous abdominal, and total body fat with rates of change in fasting insulin (FI) and insulin sensitivity (SI) over 3 years in children. Research Methods and Procedures: Seventy-seven children (mean age, 8.3 years at baseline) from Birmingham, Alabama, with three or more annual measures of FI and SI were included. Abdominal fat was measured by computed tomography, and total body fat and lean tissue mass were measured by DXA. Mixed models examined the longitudinal associations between the baseline level/rate of change of different fat compartments and the rate of change in FI or SI. Results: An annual increase of ∼5% in FI was associated with 1 cm²/yr of visceral fat gain per year (p < 0.05), independent of subcutaneous abdominal fat. A 1-cm² difference in initial subcutaneous abdominal fat was associated with an ∼0.2% increase per year in FI (p < 0.02), independent of visceral fat. None of the rates of change in any of the fat measures was associated with the rate of change of SI. Discussion: The rate of change in visceral fat was positively associated with the rate of change in FI, independent of increasing subcutaneous abdominal fat; however, subcutaneous abdominal fat may be more predictive of the rate of change of FI than visceral or total fat. Therefore, growth-related increases in abdominal fat, particularly subcutaneous abdominal fat, may contribute to accelerating increases in FI, but have no effect on SI.     

The Influence of Anatomical Boundaries,Age, and Sex on the Assessment of Abdominal Visceral Fat

CLASEY, JODY L, CLAUDE BOUCHARD, LAURIE WIDEMAN, JILL KANALEY, C DAVID TEATES, MICHAEL O THORNER, MARK L HARTMAN, ARTHUR WELTMAN. The influence of anatomical boundaries, age, and sex on the assessment of abdominal visceral fat. Single-slice abdominal computed tomography (CT) scanning has been used extensively for the measurement of abdominal visceral fat (AYF). Optimal anatomical scan location and pixel density ranges have been proposed and are specifically reported to allow for the replication and standardization of AVF measurements. Standardization of the anatomical boundaries for CT measurement of AVF and the influence of age and gender on results obtained with different boundary locations have received much less attention. To determine the influence of three boundary analysis methods (AVF-1, AVF-2, and AVF-3) on the measurement of AVF by CT, 54 older (60 years to 79 years) and 37 younger (20 years to 29 years) healthy men and women were examined. The measurement boundary for AVF-1 was the internal most aspect of the abdominal and oblique muscle walls, and the posterior aspect of the vertebral body. AVF-2 used fat measurements enclosed in a boundary formed by the midpoint of the abdominal and oblique muscle walls, and the most posterior aspect of the spinous process. AVF-3 used fat measurements enclosed in a boundary formed by the external border of the abdominal and oblique muscle walls, and the external border of the erector spinae. Greater AVF measures were obtained with AVF-2 and AVF-3 compared with AVF-1 (p<0.0001). These differences were greater in older compared with younger subjects (p<0.0001) and greater in women compared with men (p<0.02). The significantly greater AVF measurements obtained with AVF-2 and AVF-3 resulted from the inclusion of larger amounts of fat that are not drained by the portal circulation. This included retroperitoneal, intermuscular, and intramuscular lipid droplets, which increase with aging. On the basis of these results, we recommend the AVF-1 anatomical boundaries for the measurement of AVF in clinical investigations, particularly with older subjects. These data demonstrate the importance of precise and reproducible anatomical boundaries for the measurement of AVF, particularly in longitudinal studies.     

A Low Sympathoadrenal Activity is Associated with Body Weight Gain and Development of Central Adiposity in Pima Indian Men

TATARANNI P ANTONIO JAMES B YOUNG, CLIFTON BOGARDUS, ERIC RAVUSSIN. A low sympathoadrenal activity is associated with body weight gain and development of central adiposity in Pima Indian men. To investigate the possible role of impaired sympathetic nervous system and/or adrenal medullary function in the etiology of human obesity, we studied 64 Pima Indian men (28 ± 6 years, 101 ± 25 kg, 34 ± 9% body fat, mean ± SD) in whom sympathoadrenal function was estimated at baseline by measurements of 24-hour urinary norepinephrine (NE) and epinephrine (Epi) excretion rates under weight-maintenance conditions. Body weight, body composition (hydrodensitometry), and body fat distribution (waist-to-thigh circumference ratio, W/T) were measured at baseline and follow-up. Follow-up data were available on 44 subjects who gained on average 8.4 ± 9.5 kg over 3.3 ± 2.1 years. In these subjects, baseline NE excretion rate, adjusted for its determinants (i.e., fat free mass, fat mass, and W/T), correlated negatively with bodyweight gain (r=?0.38; p=0.009). Baseline Epi excretion rate correlated negatively with changes in W/T (r=?0.44; p=0.003). In conclusion, our data show for the first time that a low sympathetic nervous system activity is associated with body weight gain in humans. Also, a low activity of the adrenal medulla is associated with the development of central adiposity.     

Low Birth Weight and Normal Birth Weight Newborns of Kolkata, India: Comparison of Some Maternal Risk Factors

This study compared several maternal risk factors of low birth weight (LBW) between 204 normal birth weight (NBW) and 133 LBW newborns from Kolkata, India. Based on their birth weight (BW), newborns were classified as LBW (BW < 2.5 kg) and NBW (BW ≥ 2.5 kg). Results revealed that means for maternal age (MA, p < 0.05), gestational age (GA, p < 0.01), hemoglobin (Hb) concentration (p < 0.05), and per capita daily income (PCDI, p < 0.05) were significantly higher among mothers of NBW. Correlation analyses revealed that MA (r = 0.119, p < 0.05), GA (r = 0.583, p < 0.01), PCDI (r = 0.118, p < 0.05), and Hb (r = 0.138, p < 0.05) were significantly positively correlated with BW; PCDI was also significantly positively correlated (r = 0.142, p < 0.01) with Hb. Stepwise regression analyses with BW as the dependent variable revealed that GA (t = 7.915, p < 0.001) and Hb (t = 2.057, p < 0.05) were the most important predictive variables. The effect of Hb, independent of GA, was statistically significant (change in F = 4.231, p < 0.05). Because GA is not modifiable in pregnant women, there is a need to increase Hb levels among pregnant mothers. Most importantly, appropriately targeted preventive strategies, including iron supplementation, need to be implemented for health promotion.     

Influence of Leptin on Changes in Body Fat during Growth in African American and White Children

Objective: The aim of this study was to determine whether initial levels or temporal changes in fasting leptin were associated with longitudinal changes in body‐fat mass in children. Research Methods and Procedures: The study group consisted of 85 children (42 white and 43 African American) with a mean initial age of 8.1 ± 0.1 years. The children had between three and six annual visits for repeated measurements of body composition by DXA and fasting leptin level. Fat mass and fasting leptin level were not normally distributed and were log‐transformed. Data were analyzed using SAS Proc mixed growth models, with log fat as the dependent variable. Results: Initial leptin level was a significant predictor of the change in fat mass over time (p < 0.0001), with high initial leptin levels resulting in increased fat gain, independent of initial fat levels. This relationship remained significant when the data were analyzed separately by race (whites, p < 0.0001; African Americans, p = 0.008). The relationship between the initial level of leptin and the change in fat mass was not modified by race, sex, or Tanner Stage. The rate of change in leptin during the study was significantly related to the rate of change in fat mass in African Americans (p = 0.008) but not in whites (p = 0.490). Discussion: In conclusion, high fasting leptin level at the start of the study was significantly associated with increasing fat mass in this cohort, indicating that the children may be developing resistance to the effects of leptin.     

Weight and BMI over 6 years in Korean Children: Relationships to Body Image and Weight Loss Efforts

Objective: To investigate the relationships among longitudinal weight status, body dissatisfaction, and attitude to weight loss among Korean children from the age of 7‐8 to 13‐14 years old. Research Methods and Procedures: 351 Korean school children's heights and weights were measured at the ages of 7‐8 and 13‐14 years old; at the age of 13‐14, they completed a questionnaire about body dissatisfaction and weight loss efforts. Results: At the age of 7‐8, 15.7% of children were overweight by International Obesity Task Force standards, as compared with 26.2% at the age of 13‐14. Of the 55 7‐ to 8‐year‐old overweight children, 85.5% were still overweight at the age of 13‐14 years old. Greater concerns about body image and stronger desires to be thinner were observed among stable overweight children and among those in whom there had been a rapid increase in BMI over the 6‐year study period. Girls favored thinner shapes than did boys, regardless of their weight status or BMI changes. In girls, the level of body dissatisfaction was related only to weight loss desire, regardless of weight status or changes in BMI. In boys, however, weight loss desire was related only to weight loss attempts and was independent of weight status, BMI changes, and level of body dissatisfaction. Discussion: Regardless of weight status, changes in BMI should be considered when dealing with body dissatisfaction and attitudes to weight loss in children.     

参考家系鸡黑素皮质素受体3基因多态性与体重关系研究

鼠遗传学研究显示黑素皮质素受体3（melanocortin-3 receptor,MC3R）和MC4R在能量平衡控制中具有互补作用。敲除MC3R基因鼠表现为独有的代谢综合征和增加脂肪重量。以8周龄高体重或低体重独立选择的高体重系（high weight,HW）和低体重系（low weight,LW）白洛克鸡3代参考家系群体作为实验材料,发现了5个新的MC3R基因单核苷酸多态性（single nucleotide polymorphisms,SNPs）;建立了基于限制性内切酶Dde I的MC3R基因型的PCR-RFLP分子检测方法。方差分析结果显示MC3R基因型显著影响公鸡和母鸡的体重,以及公鸡腹脂含量。该结果建议MC3R基因可以作为侯选基因解释杂交鸡体重显著差异的原因。     

The Implications of Body Fat Mass and Fat Distribution for Cognitive Function in Elderly Women

Objective: To investigate how body fat mass, an established source of endogenous estrogen after menopause, influences cognitive impairment in elderly women. Research Methods and Procedures: Study participants were 5607 generally healthy postmenopausal women with mean age of 63.8 years at baseline followed for an average of 7.3 years. Cognitive function assessed at follow‐up using the short Blessed test was related to baseline body weight, the yearly change in weight, and follow‐up measures of body fat depots assessed by DXA. Cognitive function was also related to various surrogates of lifetime estrogen exposure. Results: Women with the worst cognitive performance (score ≥ 9) at follow‐up were the ones who lost the most body weight and revealed the lowest central fat mass (CFM). The association of weight loss with worse cognitive performance was apparent across all age groups except for those more than 80 years old. In the multivariate logistic model, the risk of cognitive impairment was 18% lower in women in the second quartile of CFM (p = 0.14), 32% lower in the third (p = 0.01), and 48% lower in the fourth (p < 0.001) compared with those in the first quartile. CFM showed significant correlation with the simultaneously measured serum estradiol (r = 0.25; p < 0.001). Cognitive score showed an inverse linear relationship with the duration of reproductive period and bone mineral density assessed at follow‐up. Discussion: These findings argue for a protective association of body fat mass with cognitive impairment in elderly women. This association seems to involve a more prominent exposure to endogenous estrogens.