Serum leptin levels and their association with several factors related to arteriosclerosis among medical students in Japan

The association between serum leptin levels and several factors related to arteriosclerosis were studied in subjects who were Japanese medical students taking no medications. The group was comprised of 75 males and 35 females. The age distribution in males was 21.4 to 29.8 years (median age, 24.0 years) and in females was 21.3 to 29.9 years (median age, 22.9 years). Statistical analyses were performed using the Wilcoxon rank sum test and Spearman correlation. Median levels of serum leptin were 3.3 ng/ml in males and 7.6 ng/ml in females. The largest correlation observed was widi percent body fat irrespective of sex [males; r=0.775, p<0.001, females; r=0.553, p<0.001]. However, body mass index (BMI) was similarly well correlated with serum leptin [r=0.631, p<0.001] in males but not in females [r=0.305, p=0.075]. A negative correlation was observed between high density lipoprotein cholesterol (HDL-C) and leptin in both sexes [males; r=-0.298, p<0.01, females; r=-0.363, p<0.05] .respectively. Percent body fat, BMI, diastolic blood pressure, apolipoprotein B, and HDL-C were the most significant factors in males. Percentage of body fat and HDL-C were the most important factors in females.     

Trends in body fat, body mass index and physical fitness among male and female college students

There have been many publications in recent years reporting on the quantity of physical activity among college students using indirect indicators such as steps walked per day or time spent on physical activities. The purpose of this study was to describe the trends of physical fitness related to BMI and body fat among university students between 1996 and 2008. The results showed a significant decline in the average fitness levels measured as an estimation of VO(2max) for male and female students (p < 0.001 for both sexes). The linear trend for BMI by years was not significant for both sexes (p for males = 0.772, p for females = 0.253). On average, in the last 13 years, % body fat was increasing 0.513%/year for males and 0.654%/year for females. There is a significant indirect correlation between the student's VO(2max) levels and % body fat, r = -0.489; p < 0.001 for males; and r = -0.416, p < 0.001 for females. Approximately 23.9% of the variance in the VO(2max) levels in males and 17.3% in females can be explained by the variance in % body fat. The results support recent findings that physical fitness among college students is declining and body fatness is increasing.     

Body fat content can be predicted in vivo in mice using a modified dual-energy X-ray absorptiometry technique.

The introduction of transgenic mice as animal models in medical research has increased the need for methods to study the phenotype of mice. The aim of the present study was to develop and evaluate a method for in vivo prediction of fat content in living mice. We combined a modified dual-energy X-ray technique with an image analysis procedure. This combined procedure calculates the percentage of fat area, defined as the percentage of the total area of the mice consisting of >50% fat. A high correlation between the percentage of fat area and dissected adipose tissue was seen in both male and female mice (males, r = 0.92, P < 0.001; females, r = 0.88, P < 0.001). A high correlation was also seen between the percentage of fat area and serum levels of leptin (males, r = 0.95, P < 0.001; females, r = 0.86, P < 0.001). An additional experiment demonstrated a very strong correlation between the percentage of fat area and total body fat as determined by chemical extraction (r = 0.97, P < 0.001). In summary, the percentage of fat area, as measured with the dual-energy X-ray/image combined procedure, provides a good in vivo estimation of total body fat content in mice.     

抗阻训练对肥胖儿童身体成分血脂及血清瘦素的影响

了解8周抗阻训练对肥胖儿童身体成分、血脂及血清瘦素的影响,为改善肥胖儿童的健康水平以及寻求更好的减肥方法提供理论依据.方法 根据WHO推荐的身高标准体重法,选取晋中市18名肥胖儿童(男、女各9名)进行8周抗阻训练,然后对运动前后身体成分[体重、体质量指数(BMI)、肌肉量及躯干肌肉量、身体脂肪量、身体各部位脂肪量及身体脂肪比率]、血脂[总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白(LDL)、高密度脂蛋白(HDL)]及血清瘦素水平进行比较.结果 肥胖儿童抗阻训练后血清瘦素、TG、LDL水平均下降(P值均<0.05),HDL水平上升(P<0.01);男性肥胖儿童抗阻训练后体重,BMI,身体脂肪量,左右上肢及躯干脂肪量均下降(P值均<0.05),肌肉量及躯干肌肉量均增加(P值均<0.05);女性肥胖儿童抗阻训练后BMI,身体脂肪量,右下肢、右上肢及躯干脂肪量均下降(P值均<0.05),肌肉量及躯干肌肉量增加(P值均<0.01).结论 8周抗阻训练可以降低肥胖儿童BMI、身体脂肪量和血清瘦素水平,增加肌肉质量,改善血脂紊乱.     

Is there a unique measuring method to assess obesity?

In the literature there is not available a uniformly accepted method for assessing the degree of obesity. AIM: To determine how far insulin resistance, serum levels of leptin and resistin are altered in persons categorized on the basis of body-mass index (BMI), body fat percentage, and abdominal circumference. METHODS: 101 volunteer boys and 115 girls participated in the studies. Body height was measured, body mass, abdominal circumference, and body composition were determined by InBody3 bioimpedance instrument. Body mass index and body fat percentage were calculated by the instrument. Concentrations of serum glucose, insulin, leptin, and resistin were determined. Insulin resistance was calculated using the homeostasis model: HOMA IR . RESULTS: Body fat percentage, serum levels of leptin and resistin were significantly higher in girls than in boys. Increases in BMI, body fat percentage, and abdominal circumference were associated with the significant elevation of both HOMA IR and serum leptin concentrations. In overweight boys categorized by body fat percentage as obese the serum leptin concentrations were significantly higher than in their non-obese counterparts. CONCLUSION: Determination of body composition would be important concerning the follow-up of biochemical changes occurring in the body during the course of both epidemiological studies and nutritional interventions.     

医学生进食行为与体成分的相关性

  目的  探讨医学生体成分和进食行为相关性,为提高医学生身体素质提供相应的科学依据。  方法  2021年12月,采用分层整群随机抽样方法对济宁医学院校大一至大四445名在校医学生进行问卷调查和身体成分测量。  结果  女生中低骨骼肌量152名(53.3%),男生低骨骼肌量45名(28.1%);肌肉量低于标准的有167名(37.5%),其中女生115名(40.4%),男生49名(30.6%);体脂百分比高于标准的259名(58.2%),女生179名(62.8%),男生80名(50.0%);腰臀比异常192名(43.1%),女生139名(48.8%),男生53名(33.1%)。女生情绪性进食得分高于男生(6.85±2.24,6.11±2.69),差异有统计学意义(t=2.96,P < 0.05)。认知限制性进食和骨骼肌量、肌肉量呈正相关(r值分别为0.13,0.13,P值均 < 0.05);情绪性进食与体脂百分比、体脂肪和腰臀比呈正相关(r值分别为0.20,0.20,0.16,P值均 < 0.05);非限制性进食与体脂百分比、体脂肪和腰臀比呈正相关(r值分别为0.15,0.18,0.15,P值均 < 0.05)。多重线性回归分析显示,性别、家庭所在地、体力活动以及认知限制性进食是影响医学生骨骼肌量、肌肉量的因素(P值均 < 0.05)。  结论  医学生中存在骨骼肌量低、肌肉量低、体脂百分比和腰臀比高的现象,应当采用合理进食习惯结合抗阻运动的方式提高体质健康水平。     

Relationship of serum adiponectin and leptin concentrations with body fat distribution in humans

OBJECTIVE: We investigated whether serum concentrations of adiponectin are determined by body fat distribution and compared the findings with leptin. RESEARCH METHODS AND PROCEDURES: Serum concentrations of adiponectin and leptin were measured by radioimmunoassay (n = 394) and analyzed for correlation with sex, age, and body fat distribution, i.e., waist-to-hip ratio, waist and hip circumference, and subcutaneous adipose tissue area of the lower leg as assessed by magnetic resonance imaging. RESULTS: After adjusting for sex and percentage of body fat, adiponectin was negatively (r = -0.17, p < 0.001) and leptin was positively (r = 0.22, p < 0.001) correlated with waist-to-hip ratio. Leptin, but not adiponectin, correlated with both waist (r = 0.49, p < 0.001) and hip circumference (r = 0.46, p < 0.001). Furthermore, leptin, but not adiponectin, correlated with the proportion of subcutaneous fat of the lower leg cross-sectional area (r = 0.37, p < 0.001). DISCUSSION: These data suggest that both adipocytokines are associated with central body fat distribution, and serum adiponectin concentrations are determined predominantly by the visceral fat compartment.     

Cigarette smoking, alcohol use, and physical activity in relation to serum leptin levels in a multiethnic population: The Miami Community Health Study

PURPOSE: To examine the correlates of plasma leptin, including fasting insulin, adiposity, and several health habits and behaviors among a nondiabetic multiethnic population. METHODS: A cross-sectional study was conducted among 25-44 year old African-Americans (n = 126), Cuban-Americans (n = 107), and non-Hispanic whites (n = 189) randomly selected from Dade County Florida. Fasting leptin levels were correlated with fasting insulin, percent body fat, smoking, alcohol use, and physical activity within each sex. Multiple linear regression and analysis of covariance were used to estimate the independent determinants of plasma leptin concentration separately among men and women. RESULTS: Stepwise linear regression analyses revealed statistically significant associations of leptin with percent body fat, fasting insulin, cigarette smoking, and physical activity (both inversely) among men (p < 0.05 for each). Among women, percent body fat, fasting insulin (both positively), cigarette smoking, and alcohol use (inversely) were independent predictors of leptin levels explaining over 70% of the variance. Analyses of covariance revealed that women had higher adjusted mean leptin levels than men (13.1 ng/ml vs. 5.9 ng/ml; p < 0.001), whereas no separate effect of ethnicity was noted. CONCLUSIONS: Although adiposity was the strongest correlate of leptin levels, fasting insulin and several health habits and behaviors were independently associated with leptin. After adjustment for these factors, women had significantly higher mean leptin levels than men. The independent association among leptin and insulin levels is intriguing and suggests additional avenues for epidemiologic research.     

单纯性肥胖儿童血脂、脂蛋白、载脂蛋白的研究

目的：通过对单纯性肥胖儿童的血脂、脂蛋白、载脂蛋白进行研究，探讨其发生动脉粥样硬化（AS）的危险性。方法：对54名肥胖儿童和60名正常体重儿童分别测定其血清脂质、脂蛋白、载脂蛋白，同时测定腰围、臀围、皮褶厚度，计算腰臀围比（WHR）、体脂百分比（％BF）、脂肪组织（FM）。结果：肥胖组儿童血清甘油三酯（TG）、低密度脂蛋白胆固醇（LDL－C）、极低密度脂蛋白胆固醇（VLDL－C）和载脂蛋白B100(apoB100)的浓度高于非肥胖组（P＜0．05），而高密度脂蛋白胆固醇（HDL－C）、载脂蛋白AI（apoAI)的浓度却低于非肥胖组，差异有显著性（P＜0．05），肥胖组与非肥胖组儿童总胆固醇（TC）浓度差异没有显著性（P＞0．05）。结论：单纯性肥胖儿童脂质代谢出现紊乱，肥胖儿童发生AS的危险性增加。     

Leptin and body composition in healthy postmenopausal women

BACKGROUND: Leptin has been proposed to be involved in central control of adiposity and fat distribution but the role of this peptide is controversial. The aim of our study was to test the relationship between serum leptin and body composition, fat distribution, and some biochemical markers such as fasting insulinemia and lipoproteins in a population of healthy Italian postmenopausal women. METHODS: One hundred and twenty-three postmenopausal women (62.1+/-8.7 years) were evaluated. Body composition (fat and lean mass) was assessed by dual-energy X-ray absorptiometry (DXA). Two regions of interest were determined for regional fat analysis. Serum leptin and insulinemia were measured by radioimmunoassay, lipoproteins with colorimetric methods and apolipoproteins nephelometrically. RESULTS: Plasma leptin levels are strongly related to total fat mass, in grams (r=0.73, p<0.001) or as a percentage of soft tissue (r=0.75, p<0.001), and to adiposity, calculated as ratio between lean and fat mass (r=0.76, p<0.001). A significant correlation was also found between serum leptin and central fat distribution (r=0.29, p<0.01). As concerns biochemical markers, serum leptin was significantly related to fasting insulin (r=0.38, p<0.001), total cholesterol (r=0.29, p<0.01), Apolipoprotein-B (r=0.35, p<0.001), and triglycerides (r=0.22, p<0.05). When corrected for total fat mass, the partial correlation coefficients remain significant for percentage of total body fat (r=0.27, p<0.01), adiposity (r=0.23, p<0.01), and fat proportion in android region (r=0.18, p<0.05). CONCLUSIONS: These data indicate that leptin levels are related to adiposity and fasting insulin levels; indeed fast insulin mantains significant correlation with leptin (r=0.23, p<0.01) after controlling for fat mass. Android distribution of fat mass in elderly women is associated with leptin concentration.     

The associations between serum leptin, adiponectin and intercellular adhesion molecule-1 in hypercholesterolemic patients

We examined the associations between adiponectin or leptin and serum ICAM-1 levels in seventy-six hypercholesterolemic patients (mean age 59 yrs, 25 males and 51 females, LDL-cholesterol>=130mg/dL at screening). Blood lipid profiles and HOMA-IR derived from fasting glucose and insulin concentrations were determined. Serum levels of adiponectin, leptin and ICAM-1 were analyzed using ELISA. The results showed that serum levels of leptin were positively associated with serum levels of ICAM-1 independent of age, sex and BMI (r =0.392, p<0.001). Serum levels of adiponectin were negatively associated with serum levels of ICAM-1 independent of age, sex and BMI (r =-0.343, p<0.005). Stepwise multiple linear regression analysis showed that serum leptin was an independent factor to be associated with serum ICAM-1 levels after adjusting for age, sex, BMI, alcohol intake, smoking status, blood lipids such as total cholesterol, triglyceride, HDL cholesterol and LDL cholesterol and HOMA-IR (p<0.001). With respect to adiponectin, its association with serum ICAM-1 was attenuated but still significant when further adjustments were made for age, sex, BMI, alcohol intake, smoking status, blood lipids such as total cholesterol, triglyceride, HDL cholesterol and LDL cholesterol and HOMA-IR (p<0.005). In conclusion, this study suggests that adiponectin and leptin are associated with endothelial derived inflammation.     

Lower serum leptin levels in female students of the nutritional sciences with eating disorders

Summary. Background: Evidence has accumulated that in both acutely ill and recovered patients with either anorexia or bulimia nervosa circulating leptin levels (LL) are lower than in controls matched for body mass index (BMI; kg/m²). It is unknown if these lower leptin levels represent a state or trait marker. Aim of the study: We aimed to confirm the lowered leptin levels in eating disordered females and to identify underlying mechanisms. Methods: We screened 181 female students of the nutritional sciences for eating disorders with the respective module of the M-Composite International Diagnostic Interview and the Cognitive Restraint scale of the Three Factor Eating Questionnaire. The physical assessment included determinations of BMI, body composition and LL. Each case fulfilling lifetime DSM-IV criteria for an eating disorder was BMI matched to two controls. We used a multivariate mixed regression model to evaluate if the observed difference in lg₁₀-leptin level between cases and controls is actually due to the influence of restrained eating and/or previous weight loss after adjustment for BMI and percent body fat. Results: In accordance with our hypothesis the 32 (17.7 %) cases had a lower serum lg₁₀-leptin level than the 64 BMI matched controls (one-sided p < 0.001). We were not able to detect an influence of restrained eating or previous weight loss. Conclusions: We confirm that females with a lifetime history of an eating disorder have lower LL. We were not able to identify an underlying mechanism. Similar to most previous studies we found a high rate of eating disorders among female students of nutritional sciences. Received: 24 June 2002, Accepted: 12 December 2002 Correspondence to: Prof. Johannes Hebebrand     

Serum leptin and lipid profiles in Thai obese and overweight subjects

The weight, height, body mass index (BMI), waist/hip ratio, serum leptin and lipid profiles of 48 overweight (BMI > or = 25.00). Thai males and 166 overweight Thai females, compared with 26 males and 81 females in a control group (BMI = 18.5-24.9 kg/m2), were investigated. Subjects for the study were those persons who turned up regularly for physical check-ups at the out-patient department, general practice section of the Rajvithi Hospital, Bangkok. The study was conducted between March-October, 1998. Statistically significantly higher levels of serum leptin, cholesterol, LDL-C, LDL-C/HDL-C ratio and triglyceride were found in the overweight compared with the control subjects. The median serum leptin concentration in overweight subjects was 19.6 (2.0-60.0 ng/ml) compared with 9.0 (range 1.0-30.0 ng/ml) in the control subjects (p < 0.001). The median values of leptin serum concentrations in the overweight and obese males were significantly higher than those of the overweight and obese females. A total of 66.7% (32 out of 48) of the overweight and obese males had elevated leptin levels, while elevated leptin levels were found in 87.3% (145 out of 166) of the overweight and obese females. A total of 18.8% and 21.1% of the overweight and obese males and females respectively had cholesterol concentrations of > or = 6.48 mmol/l. However, the prevalence of low HDL-C (HDL-C < or = 0.91 mmol/l) was found to be 41.7% in the overweight and obese males and 4.2% in the overweight and obese females. Statistically significant associations were found between weight, height, BMI, waist, hip, waist/hip ratio, HDL-C, and serum leptin in both overweight male and female subjects. A negative correlation was found between serum leptin and LDL-C/HDL-C ratio in both the overweight and obese subjects.     

Serum leptin levels in patients with hyperlipidemias

Leptin is a protein hormone produced by adipocytes that reflects the body fat content. The aim of our study was to compare serum leptin levels in randomly selected untreated males and females with hypercholesterolemia and combined hyperlipidemia and in healthy control subjects matched for age and body mass index and to study the relations between leptin and serum lipids and lipoproteins. No statistically significant differences in serum leptin levels were found between the male control group (5.26 +/- 2.81 ng/mL(-1)) and the male group with hypercholesterolemia (8.16 +/- 3.85 ng/mL(-1)) or combined hyperlipidemia (7.51 +/- 4.83 ng/mL(-1)) and between the female control group (13.0 +/- 8.12 ng/mL(-1)) and the female group with hypercholesterolemia (15.36 +/- 8.89 ng/mL(-1)) or combined hyperlipidemia (18.63 +/- 10.15 ng/mL(-1)). Leptin concentration in male group with hypercholesterolemia did not differ significantly from the female control group; in the other male groups, leptin levels were significantly lower than those of the other female groups. Serum leptin levels in all studied groups except for the male group with hypercholesterolemia positively correlated with body mass index. Serum leptin levels correlated negatively with high-density lipoprotein cholesterol in the female group with hypercholesterolemia (r = -0.67, P < 0.01) and the male group with combined hyperlipidemia (r = -0.56, P < 0.01). A positive correlation between serum leptin and high-density lipoprotein cholesterol (r = 0.67, P < 0.01) and between leptin and lipoprotein (a) (r = 0.71, P < 005) was found in female group with combined hyperlipidemia. No other significant relationships between leptin and serum lipids or lipoproteins were found. We conclude that serum leptin levels in patients with hyperlipidemias do not significantly differ from those healthy control subjects matched by age and body mass index.     

Impact of visceral fat on blood pressure and insulin sensitivity in hypertensive obese women

OBJECTIVE: The relationship among body fat distribution, blood pressure, serum leptin levels, and insulin resistance was investigated in hypertensive obese women with central distribution of fat. RESEARCH METHODS AND PROCEDURES: We studied 74 hypertensive women (age, 49.8 +/- 7.5 years; body mass index, 39.1 +/- 5.5 kg/m(2); waist-to-hip ratio, 0.96 +/- 0.08). All patients were submitted to 24-hour blood pressure ambulatory monitoring (24h-ABPM). Abdominal ultrasonography was used to estimate the amount of visceral fat (VF). Fasting blood samples were obtained for serum leptin and insulin determinations. Insulin resistance was estimated by homeostasis model assessment insulin resistance index (HOMA-r index). RESULTS: Sixty-four percent of the women were postmenopausal, and all patients showed central distribution of fat (waist-to-hip ratio > 0.85). The VF correlated with systolic 24h-ABPM values (r = 0.28, p = 0.01) and with HOMA-r index (r = 0.27; p = 0.01). VF measurement (7.5 +/- 2.3 vs. 5.9 +/- 2.2 cm, p < 0.001) and the systolic 24h-ABPM (133 +/- 14.5 vs. 126 +/- 9.8 mm Hg, p = 0.04), but not HOMA-r index, were significantly higher in the postmenopausal group (n = 48) than in the premenopausal group (n = 26). No correlations were observed between blood pressure levels and HOMA-r index, leptin, or insulin levels. In the multiple regression analysis, visceral fat, but not age, body fat mass, or HOMA-r index, correlated with the 24h-ABPM (p = 0.003). DISCUSSION: In centrally obese hypertensive women, the accumulation of VF, more often after menopause, is associated with higher levels of blood pressure and insulin resistance. The mechanism through which VF contributes to higher blood pressure levels seems to be independent of leptin or insulin levels.     

Leptin's sexual dimorphism results from genotype by sex interactions mediated by testosterone.

OBJECTIVE: Recent studies have reported the existence of marked sexual dimorphism in serum leptin levels in humans, with women having approximately three times the levels of men. As we have shown for other measures of adiposity, such sexual dimorphism can arise from a special case of genotype by environment interaction, that of genotype by sex interaction. RESEARCH METHODS AND PROCEDURES: Using maximum likelihood-based variance decomposition techniques, we examined the genetic and environmental architecture of sexual dimorphism in serum leptin levels in 1147 Mexican Americans from the San Antonio Family Heart Study. RESULTS: Both the genetic and environmental variances for this trait differed significantly between the sexes (p < 0.001 and p < 0.01, respectively), with women displaying larger values for both components. We found significant evidence that different genes influence variation in serum leptin levels between the two sexes (p = 0.05). Furthermore, this pattern of sexual dimorphism in serum leptin levels persisted even after accounting for the effects of either the percentage of body fat or total body fat. However, this pattern of sexual dimorphism was eliminated after accounting for the effects of testosterone. DISCUSSION: These findings suggest that the sexual dimorphism seen in leptin levels is not simply explained as differences in total adiposity between the sexes. We conclude that the genes, which influence variation in serum leptin levels, are differentially expressed depending on sex, and that the sexes also show differences in response of the expression of this obesity-related trait to unmeasured residual effects.     

单纯性肥胖儿童血清瘦素水平与血糖及血脂变化的关系

目的 研究单纯性肥胖儿童血清瘦素水平与血糖、胰岛素抵抗及血脂异常的关系。方法 采用放射免疫分析法、酶法对42对7-10岁肥胖及健康对照儿童进行血清瘦素、胰岛素水平及血糖、血脂水平的测定。结果 肥胖及对照儿童瘦素水平分别为2．74-45．125μg/L和0．53-10．18μg/L,经对数转换后肥胖组平均水平非常显著高于体重正常组。血清瘦素水平与体重指数(BMI)、腰臀围比(WHR)及体脂百分比均呈显著正相关关系。83％的肥胖儿童有瘦素抵抗,肥胖瘦素敏感组与体重正常组的血糖、胰岛素及血脂水平均差异无显著性,而肥胖瘦素抵抗组总胆固醇、甘油三酯(TG)、低密度脂蛋白胆固醇及胰岛素水平均显著高于体重正常组,肥胖瘦素敏感与瘦素抵抗儿童年龄、性别分布及BMI、WHR的差异无显著性,但瘦素抵抗组TG显著高于瘦素敏感组,高密度脂蛋白胆固醇显著低于瘦素敏感组。结论 肥胖儿童即存在瘦素抵抗,瘦素抵抗与代谢综合征及心血管疾病的危险因素密切相关,可作为筛查高危肥胖儿童的有用指标。     

Associations among eating regulation and body mass index,weight, and body fat in college students: The moderating role of gender

This study investigated associations between eating regulation behaviors and body mass index (BMI), weight, and percent body fat in male and female students over the first two years of college. Subjects included 328 college students (215 females and 113 males). Height and weight (via standard techniques), body composition (via bioelectrical impedance analysis), and eating regulation behaviors (using the Regulation of Eating Behavior Scale) were conducted two to three times during both the freshman and sophomore years. Significant associations between eating regulation and BMI, weight, and/or percent body fat were shown mostly in females. In females, higher BMI, weight, and/or percent body fat at the end of the second year of college were found in those with low levels of autonomous, intrinsic motivation, and identified regulation, and high levels of amotivation, while lower BMI, weight, and/or percent body fat were associated with high levels of autonomous, intrinsic motivation, and identified regulation, and low levels of amotivation. The findings that specific eating behaviors in females during the first two years of college influence BMI, weight, and/or percent body fat may be useful for inclusion in university programs focused on college student health to help decrease the risk of obesity and disordered eating/eating disorders in female college students.     

Serum leptin concentrations and body adipose measures in older black and white adults

BACKGROUND: Among US adults, serum leptin concentrations are higher in women than in men and are higher in blacks than in whites independent of anthropometric measures of body fatness. OBJECTIVE: Using radiographic measures of body fat, we determined the best correlates of leptin and whether adiposity can explain sex and race differences in leptin concentrations in older adults. DESIGN: This was a cross-sectional analysis of fasting serum leptin concentrations and body fat measured by dual-energy X-ray absorptiometry (DXA), abdominal computed tomography, and standard anthropometry in 3026 well-functioning 70-79-y-old participants (42% black, 51% women) of the Health, Aging, and Body Composition Study. RESULTS: Geometric mean (+/-SE) leptin concentrations (ng/mL) were higher in the women than in the men (16.5 +/- 0.3 and 5.7 +/- 0.1, respectively) and in the black women than in the white women (20.2 +/- 0.6 and 13.9 +/- 0.4, respectively), but did not differ significantly between the white and black men (5.8 +/- 0.2 and 5.5 +/- 0.2, respectively). Percentage fat estimated from DXA showed the highest correlation with leptin (R(2) = 0.56 for both sexes). Addition of abdominal visceral fat minimally increased the correlation. In the multivariate analysis, the association with sex was eliminated after adjustment for percentage fat and visceral fat in both whites (P = 0.051) and blacks (P = 0.34). Among women, higher leptin concentrations in blacks remained after adjustment for percentage fat and visceral fat (mean race difference = 4.95 ng/mL; P < 0.001). Among men, an association with black race emerged after adjustment for these factors (mean race difference = 1.42 ng/mL; P < 0.001). CONCLUSIONS: Among older adults, higher serum leptin concentrations in women are explained by a greater percentage of body fat. Higher leptin concentrations in blacks are not explained by percentage of body fat.     

儿童血清ghrelin水平与血脂、瘦素、脂联素及胰岛素关系的分析

目的探讨儿童血清ghrelin水平与血脂、瘦素、脂联素及胰岛素的关系。方法采用多阶段随机抽样的方法,随机抽取879名8～10岁小学生作为调查对象。测量身高、体重、腰围,计算体质指数(BMI)、体脂百分比(%BF),测定血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、空腹血糖、ghrelin、脂联素、胰岛素及瘦素。结果随血清ghrelin水平的升高,体重、腰围、BMI、%BF、血清瘦素水平逐渐降低(P<0.0001),血清HDL-C水平呈现逐渐增高的趋势(P<0.0001),血清TC、胰岛素和脂联素水平变化趋势不明显;与ghrelin密切相关的指标为体成分指标,包括身高、体重、腰围、BMI、%BF以及瘦素,其次是血脂代谢指标,包括TG、HDL-C、TC、LDL-C,第三是血糖代谢指标,包括空腹血糖和胰岛素。结论ghrelin与体成分指标、瘦素、脂联素、胰岛素以及血脂有不同程度的关联,但和身高、体重、腰围、BMI、%BF以及瘦素的相关最为密切。