ADRB2 and LEPR gene polymorphisms: synergistic effects on the risk of obesity in Japanese

The objective of the present study was to validate a recently reported synergistic effect between variants located in the leptin receptor (LEPR) gene and in the β-2 adrenergic receptor (ADRB2) gene on the risk of overweight/obesity. We studied a middle-aged/elderly sample of 4,193 nondiabetic Japanese subjects stratified according gender (1,911 women and 2,282 men). The LEPR Gln223Arg (rs1137101) variant as well as both ADRB2 Arg16Gly (rs1042713) and Gln27Glu (rs1042714) polymorphisms were analyzed. The primary outcome was the risk of overweight/obesity defined as BMI ≥25 kg/m(2), whereas secondary outcomes included the risk of a BMI ≥27 kg/m(2) and BMI as a continuous variable. None of the studied polymorphisms showed statistically significant individual effects, regardless of the group or phenotype studied. Haplotype analysis also did not disclose any associations of ADRB2 polymorphisms with BMI. However, dimensionality reduction-based models confirmed significant interactions among the investigated variants for BMI as a continuous variable as well as for the risk of obesity defined as BMI ≥27 kg/m(2). All disclosed interactions were found in men only. Our results provide external validation for a male specific ADRB2-LEPR interaction effect on the risk of overweight/obesity, but indicate that effect sizes associated with these interactions may be smaller in the population studied.     

LEPR p.Q223R, beta3-AR p.W64R and LEP c.-2548G>A gene variants in obese Brazilian subjects

Obesity is due to the combined effects of genes, environment, lifestyle, and the interactions of these factors. The adrenergic receptor beta3 (beta3-AR), leptin (LEP) and leptin receptor (LEPR) genes have been intensively evaluated in the search of variants that could be related to obesity and its cardiometabolic complications. The results of most of these studies have been controversial. In the present study, we investigated the relationship of the beta3-AR p.W64R, LEP c.-2548G>A and LEPR p.Q223R gene variants with body mass index (BMI), in Brazilian subjects of different genetic backgrounds and ethnic origins. Two hundred obese patients (60 males, 140 females, BMI > or = 30 kg/m2) were screened and compared to 150 lean healthy subjects (63 males, 87 females, BMI < or = 24 kg/m2). Genomic DNA was extracted and amplified by polymerase chain reaction. Polymerase chain reaction products were digested with specific restriction enzymes and separated by electrophoresis. There was no significant difference in the genotype frequency of the beta3-AR p.W64R and the LEP c.-2548G>A polymorphisms, between lean and obese subjects. However, the genotype and allele frequencies of the LEPR p.Q223R variant were significantly different between the normal weight and obese groups. Haplotype analysis has shown an association between the G/G allelic combination of c.-2548G>A LEP and c.668A>G LEPR, in obese subjects. Our results suggest that genetic variability in the leptin receptor is associated with body weight regulation, the LEPR p.Q223R variant being related to BMI increase. The haplotype combination of LEP c.-2548G>A and LEPR p.Q223R variants was related to a 58% increase in obesity risk.     

G-2548A polymorphism of the leptin gene is correlated with extreme obesity in Taiwanese aborigines

We examined the genetic associations of the G-2548A polymorphism in the promoter of the leptin (LEP) gene and the Gln223Arg (Q223R) polymorphism of the leptin receptor (LEPR) gene with obesity. Two hundred twenty-six obese aboriginal subjects (BMI > or = 27 kg/m2) and 182 aboriginal subjects with normal weight (BMI < 25 kg/m2) participated in this study. The polymorphisms of LEP G-2548A and LEPR Q223R were genotyped by polymerase chain reaction/restriction fragment length polymorphism, and their anthropometric characteristics were measured. Levels of leptin, triglycerides, and cholesterol were measured after overnight fasting. We found that the frequencies of the LEP G/G homozygote (22.6%) with Mendelian recessive (chi2 = 7.89, p = 0.005) and codominant (chi2 = 7.93, p = 0.02) models to be higher in the extremely obese subjects (BMI > or = 35 kg/m2) than in normal weight subjects (6.9%) but not in moderately obese subjects (35 > BMI > or = 27 kg/m2). There was no difference in genotypic frequency of the LEPR Q223R polymorphism between the extreme obese and control groups. We suggest that the LEP -2548 G/G homozygote plays a genetic recessive role in the development of extreme obesity in Taiwanese aborigines.     

Microsatellites proximal to leptin and leptin receptor as risk factors for spina bifida

Several recent studies have observed an association between neural tube defect risk and prepregnant obesity. This association was generally stronger for spina bifida and was observed irrespective of additional maternal factors, including periconceptional intake of vitamin supplements. Other studies have identified mutations within the genes that code for leptin (LEP) and its receptor (LEPR), which have been linked to obesity in mice and humans. We investigated the potential association between nucleotide variation at the LEP and LEPR loci, and increased risk of spina bifida. We searched specifically for allelic association at a pair of highly polymorphic microsatellites closely linked to either the LEP or LEPR gene. Data were derived from a population-based case-control study that had previously identified an association between a woman's prepregnant obesity and her risk of delivering an infant with spina bifida. A total of 56 spina bifida case infants and 126 nonmalformed control infants were genotyped for 10 microsatellite alleles closely linked to the LEP gene, and 49 cases and 125 controls were genotyped for 10 microsatellite alleles closely linked to the LEPR gene. In general, alleles were not observed to be exclusively associated with substantially greater spina bifida risk in the body mass index (BMI) category (obese) of >29 kg/m(2) compared with the BMI category (nonobese) of 29 kg/m; (2) having either allele and BMI 29 kg/m(2). The odds ratios (95% confidence interval) for these comparisons were: for allele 257, 4.5 (1.1-19.4), 1.9 (0.5-6.3), and 2.9 (1.3-6.4), respectively, and for allele 271, 6.7 (1.6-30.4), 2.7 (0.7-10.9), and 2.7 (1.2-5.9), respectively. Owing to the exploratory nature of this investigation, the significance of these latter results is unclear.     

Associations among Lipids, Leptin, and Leptin Receptor Gene Gin223Arg Polymorphisms and Breast Cancer in China

We evaluated the relationship among the leptin receptor (LEPR) gene Gln223Arg polymorphism, body mass index (BMI), waist and hip circumference ratio (WHR), dietary structure, lifestyle, and other biomarkers with breast cancer and determined whether they could be effective for the prevention and treatment of breast cancer. The Gln223Arg polymorphisms in the LEPR gene were investigated in blood deoxyribonucleic acid (DNA) available for 240 breast cancer cases and 500 controls. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. Leptin, insulin were determined by enzyme-linked immunosorbent assays. We found that the serum levels of leptin, insulin, triglyceride (TG), free cholesterol (FCH), apolipoprotain (APO) A1, and BMI were significantly higher in breast cancer cases than the controls, while physical activity was clearly less in breast cancer cases (P < 0.02 approximately P < 0.001, respectively). Moreover, there were significant association between the Gln223Arg genotype and breast cancer risk; homozygotes for AA and heterozygotes for AG,AG + GG genotypes had been proved to increase the risk of breast cancer, and their corresponding odds ratio were 7.14 (95% confidence interval [CI] = 1.92-25.64), 1.33(95% CI = 1.03-2.70), and 2.04 (95% CI = 1.09-3.82). Interestingly, logistic regression analysis showed that LEPR gene Gln223Arg polymorphism and elevated leptin, insulin, TG, FCH, APOA1, WHR, and reduced APOB increased the risk of developing breast cancer, respectively. And, it also suggested that LEPR gene Gln223Arg polymorphisms, elevated leptin, insulin, TG, FCH, APOA1, WHR, and reduced APOB should play a major role in the development of breast cancer.     

Human-Specific SNP in Obesity Genes, Adrenergic Receptor Beta2 (ADRB2), Beta3 (ADRB3), and PPAR γ2 (PPARG), during Primate Evolution

Adrenergic-receptor beta2 (ADRB2) and beta3 (ADRB3) are obesity genes that play a key role in the regulation of energy balance by increasing lipolysis and thermogenesis. The Glu27 allele in ADRB2 and the Arg64 allele in ADRB3 are associated with abdominal obesity and early onset of non-insulin-dependent diabetes mellitus (NIDDM) in many ethnic groups. Peroxisome proliferator-activated receptor γ (PPARG) is required for adipocyte differentiation. Pro12Ala mutation decreases PPARG activity and resistance to NIDDM. In humans, energy-expense alleles, Gln27 in ADRB2 and Trp64 in ADRB3, are at higher frequencies than Glu27 and Arg64, respectively, but Ala12 in PPARG is at lower frequency than Pro12. Adaptation of humans for lipolysis, thermogenesis, and reduction of fat accumulation could be considered by examining which alleles in these genes are dominant in non-human primates (NHP). All NHP (P. troglodytes, G. gorilla, P. pygmaeus, H. agilis and macaques) had energy-thrifty alleles, Gly16 and Glu27 in ADRB2, and Arg64 in ADRB3, but did not have energy-expense alleles, Arg16, Gln27 and Trp64 alleles. In PPARG gene, all NHP had large adipocyte accumulating type, the Pro12 allele. CONCLUSIONS: These results indicate that a tendency to produce much more heat through the energy-expense alleles developed only in humans, who left tropical rainforests for savanna and developed new features in their heat-regulation systems, such as reduction of body hair and increased evaporation of water, and might have helped the protection of entrails from cold at night, especially in glacial periods.     

2型糖尿病家系患者LEPR基因Gln223Arg多态性的研究

目的：研究黑龙江地区汉族人2型糖尿病家系的LEPR基因Gln223Arg多态性,探讨其与2型糖尿病发病的关系。方法：应用聚合酶链式反应-限制性内切酶长度多态性（PCR-RFLP）技术,对来自于黑龙江地区120个2型糖尿病家系中的210例2型糖尿病患者及319例正常对照的LEPR基因Gln223Arg（668 A→G）位点进行基因分型。结果：LEPR基因Gln223Arg三种基因型在病例组和对照组间整体分布有统计学意义（P=0.034,df=2）;除AG基因型（x2=4.550,P〈0.01）外,其余各基因型及等位基因在病例组和对照组间分布未见显著性差异（P〉0.05）。结论：LEPR基因Gln223Arg多态性与黑龙江地区汉族人2型糖尿病有关,LEPR基因可能为中国人2型糖尿病发病的相关易感基因。     

Association of PPARG2 Pro12Ala variant with larger body mass index in Mestizo and Amerindian populations of Mexico

Previous studies have sought to associate the Pro12Ala variant of the peroxisome proliferator-activated receptor gamma2 (PPARG2) gene with type 2 diabetes, insulin resistance, and obesity, with controversial results. We have determined the Pro12Ala variant frequency in 370 nondiabetic Mexican Mestizo subjects and in five Mexican Amerindian groups and have investigated its possible association with lipid metabolism, insulin serum levels, and obesity in three of these populations. Two independent case-control studies were conducted in 239 nondiabetic individuals: 135 case subjects (BMI > or = 25 kg/m2) and 104 control subjects (BMI < 25 kg/m2). The PPARG2 Ala12 allele frequency was higher in most Amerindian populations (0.17 in Yaquis, 0.16 in Mazahuas, 0.16 in Mayans, and 0.20 in Triquis) than in Asians, African Americans, and Caucasians. The Pro12Ala and Ala12Ala (X12Ala) genotypes were significantly associated with greater BMI in Mexican Mestizos and in two Amerindian groups. X12Ala individuals had a higher risk of overweight or obesity than noncarriers in Mestizos (OR = 3.67; 95% CI, 1.42-9.48; p = 0.007) and in Yaquis plus Mazahuas (OR = 3.21; 95% CI, 1.27-8.11; p = 0.013). Our results provide further support of the association between the PPARG2 Ala12 allele and risk of overweight or obesity in Mestizos and two Amerindian populations from Mexico.     

Association of INSIG2 Polymorphism with Overweight and LDL in Children

Background

Dyslipidemia and overweight are common issues in children. Identifying genetic markers of risk could lead to targeted interventions. A polymorphism of SNP rs7566605 near insulin-induced gene 2 (INSIG2) has been identified as a strong candidate gene for obesity, through its feedback control of lipid synthesis.

Objective

To identify polymorphisms in INSIG2 which are associated with overweight (BMI ≥ 85% for age) and dyslipidemia in children. Hypothesis: The C allele of rs7566605 would be significantly associated with BMI and LDL.

Design/Methods

We genotyped 15 SNPs in/near INSIG2 in 1,058 healthy children (53% non-Hispanic white (NHW), 37% overweight) participating in a school based study. Genotype was compared with BMI and lipid markers, adjusting for age, gender, and puberty.

Results

We found a significant association between the SNP rs12464355 and LDL in NHW children, p < 0.001. The G allele is protective (lower LDL). A different SNP was associated with overweight in NHW: rs17047757. SNP rs7566605 was not associated with overweight or lipid levels.

Conclusions

We identified novel genetic associations between INSIG2 and both overweight and LDL in NHW children. Polymorphisms in INSIG2 may be important in the development of obesity through its effects on lipid regulation.     

Leptin expression and leptin receptor gene polymorphisms in growth hormone deficiency patients

Growth hormone deficiency (GHD) patients have lower weight, height, bone age, insulin-like growth factor 1 (IGF-1) levels, GH levels, fat metabolism and skeletal growth. The association of leptin with GHD characteristics and the effect of gene variants of leptin on GHD are unknown. Our aim was to examine the association of circulating leptin levels and common genetic variants in leptin (LEP) and leptin receptor (LEPR) genes with anthropometric measures, circulating hormone concentrations and GHD. A case control study of 125 GHD cases and 159 control subjects were characterized for bone age, body mass index (BMI), height, weight, leptin, IGF-1, GH and their genotype at the leptin promoter G-2548A, and LEPR variants, K109R and Q223R, at Chung Shan Medical University Hospital. Leptin levels were significantly associated with lower bone age, weight and BMI in GHD patients. Leptin levels were also significantly associated with reduced IGF-1 levels in girls but not boys in both groups. The frequency of LEPR223 [A/G or A/A] genotype was significantly higher than the LEPR223 G/G genotype in the GHD group. The LEPR223 [A/G or A/A] genotype was significantly associated with increased weight and BMI in the control group, but not in the GHD group. In conclusion, the GHD group carried a significantly higher frequency of the LEPR [G/A or A/A] genotype and of the A allele (LEPR223R). The LEPR223R polymorphism affected weight and BMI in control, but not in GHD patients, suggesting that the effect of LEPR223 [A/G or A/A] genotype was counteracted by other factor(s) in GHD patients.     

Which is the best anthropometric technique to identify obesity: body mass index, waist circumference or waist-hip ratio?

This study was designed to define the most suitable anthropometric technique among body mass index (BMI), waist circumference (WC) and waist-hip ratio (WHR) as indices of obesity in adult people living in Adana, a Southern province of Turkey. A random sample design was used. A total of 900 individuals (men and non-pregnant women aged 25-65 years) were enrolled in the study. Of subjects, 50.9% were females. Anthropometric measurements were performed. Data were analysed using statistical package program. The prevalence of obesity among adults living in Adana was 20.8% 28.4% when defined using BMI, 30.5% by WC and 15.8% 42.0% by WHR. Truncal obesity and gynoid obesity showed similar prevalence with 26.6%, in the same age group. Waist circumference, BMI and WHR identified different proportions of the population, as measured for obesity prevalence. The most common methods for diagnosing overweight and obesity are based on BMI (kg/m2). However, BMI is suboptimal marker for total body fat percentage and even less suitable to assess body fat distribution. WHR is the most useful measure of obesity and the best simple anthropometric index in predicting a wide range of risk factors and related health conditions.     

Replication of 6 Obesity Genes in a Meta-Analysis of Genome-Wide Association Studies from Diverse Ancestries

Obesity is a major public health problem with a significant genetic component. Multiple DNA polymorphisms/genes have been shown to be strongly associated with obesity, typically in populations of European descent. The aim of this study was to verify the extent to which 6 confirmed obesity genes (FTO, CTNNBL1, ADRB2, LEPR, PPARG and UCP2 genes) could be replicated in 8 different samples (n = 11,161) and to explore whether the same genes contribute to obesity-susceptibility in populations of different ancestries (five Caucasian, one Chinese, one African-American and one Hispanic population). GWAS-based data sets with 1000 G imputed variants were tested for association with obesity phenotypes individually in each population, and subsequently combined in a meta-analysis. Multiple variants at the FTO locus showed significant associations with BMI, fat mass (FM) and percentage of body fat (PBF) in meta-analysis. The strongest association was detected at rs7185735 (P-value = 1.01×10⁻⁷ for BMI, 1.80×10⁻⁶ for FM, and 5.29×10⁻⁴ for PBF). Variants at the CTNNBL1, LEPR and PPARG loci demonstrated nominal association with obesity phenotypes (meta-analysis P-values ranging from 1.15×10⁻³ to 4.94×10⁻²). There was no evidence of association with variants at ADRB2 and UCP2 genes. When stratified by sex and ethnicity, FTO variants showed sex-specific and ethnic-specific effects on obesity traits. Thus, it is likely that FTO has an important role in the sex- and ethnic-specific risk of obesity. Our data confirmed the role of FTO, CTNNBL1, LEPR and PPARG in obesity predisposition. These findings enhanced our knowledge of genetic associations between these genes and obesity-related phenotypes, and provided further justification for pursuing functional studies of these genes in the pathophysiology of obesity. Sex and ethnic differences in genetic susceptibility across populations of diverse ancestries may contribute to a more targeted prevention and customized treatment of obesity.     

Leptin −2548 G/A polymorphisms are associated to clinical progression of oral cancer and sensitive to oral tumorization in nonsmoking population

Oral cancer is causally associated with environmental carcinogens, and the susceptibility to carcinogen-mediated tumorigenesis is proposed to be genotype-dependent. Leptin (LEP) and leptin receptor (LEPR) both play a crucial role in the mediation of physiological reactions and carcinogenesis and may serve as a candidate biomarker of oral cancer. The current case-control study aimed to examine the effects of LEP −2548 G/A (rs7799039), LEPR K109R (rs1137100), and LEPR Q223R (rs1137101) single-nucleotide polymorphisms (SNPs) with or without interacting to environmental carcinogens on the risk for oral squamous cell carcinoma. The SNPs of three genetic allele, from 567 patients with oral cancer and 560 healthy controls in Taiwan were analyzed. The results shown that the patients with polymorphic allele of LEP −2548 have a significant low risk for the development of clinical stage (A/G: adjusted odds ratio [AOR] = 0.670, 95% confidence interval [CI] = 0.454-0.988, P < 0.05; A/G + G/G: AOR = 0.676, 95% CI = 0.467-0.978, P < 0.05) compared to patients with ancestral homozygous A/A genotype. In addition, an interesting result was found that the impact of LEP −2548 G/A SNP on oral carcinogenesis in subjects without tobacco consumption is higher than subjects with tobacco consumption. These results suggest that the genetic polymorphism of LEP −2548 G/A (rs7799039), LEPR K109R (rs1137100), and LEPR Q223R (rs1137101) were not associated to the susceptibility of oral cancer; SNP in LEP −2548 G/A showed a poor clinicopathological development of oral cancer; population without tobacco consumption and with polymorphic LEP −2548 G/A gene may significantly increase the risk to have oral cancer.     

Effect of obesity on repeat revascularization in patients undergoing percutaneous coronary intervention with drug-eluting stents

Obesity is a major risk factor for developing coronary artery disease. The impact of obesity on prognosis among those with established coronary disease is less clear. The objective of this study was to evaluate the effect of obesity on repeat revascularization in patients undergoing percutaneous coronary intervention (PCI) with drug-eluting stents (DES). We examined 6,083 patients who were divided into three groups according to BMI: normal (BMI 18.5-24.9 kg/m(2), n = 1,592); overweight (BMI 25-29.9 kg/m(2), n = 3,026) and obese (BMI >30 kg/m(2), n = 1,465). The follow-up focused on clinical-driven repeat revascularization, including target lesion revascularization (TLR) and nonTLR. Median follow-up was 26 months (interquartile range 20-32). There was no significant difference in the incidence of TLR among normal, overweight, and obese patients (6.3% vs. 6.1% vs. 7.1%; P = 0.423). In contrast, the incidence of nonTLR was significantly higher in obese patients compared with normal and overweight (8.4% vs. 6.0% vs. 5.8%, P = 0.003). Multivariate analysis showed that obesity was an independent predictor of nonTLR during follow-up (hazard ratio = 1.39; 95% confidence interval = 1.06-1.83; P = 0.019), along with diabetes and hypercholesterolemia. Concomitant use of statins was independently associated with decreased risk of nonTLR (hazard ratio = 0.75; 95% confidence interval = 0.62-0.92; P = 0.005). In conclusion, among patients undergoing PCI with DES, obesity was not associated with TLR, but was associated with a higher risk of nonTLR.     

Contribution of Common Genetic Variants to Obesity and Obesity-Related Traits in Mexican Children and Adults

Background

Several studies have identified multiple obesity-associated loci mainly in European populations. However, their contribution to obesity in other ethnicities such as Mexicans is largely unknown. The aim of this study was to examine 26 obesity-associated single-nucleotide polymorphisms (SNP) in a sample of Mexican mestizos.

Methods

9 SNPs in biological candidate genes showing replications (PPARG, ADRB3, ADRB2, LEPR, GNB3, UCP3, ADIPOQ, UCP2, and NR3C1), and 17 SNPs in or near genes associated with obesity in first, second and third wave GWAS (INSIG2, FTO, MC4R, TMEM18, FAIM2/BCDIN3, BDNF, SH2B1, GNPDA2, NEGR1, KCTD15, SEC16B/RASAL2, NPC1, SFRF10/ETV5, MAF, PRL, MTCH2, and PTER) were genotyped in 1,156 unrelated Mexican-Mestizos including 683 cases (441 obese class I/II and 242 obese class III) and 473 normal-weight controls. In a second stage we selected 12 of the SNPs showing nominal associations with obesity, to seek associations with quantitative obesity-related traits in 3 cohorts including 1,218 Mexican Mestizo children, 945 Mexican Mestizo adults, and 543 Indigenous Mexican adults.

Results

After adjusting for age, sex and admixture, significant associations with obesity were found for 6 genes in the case-control study (ADIPOQ, FTO, TMEM18, INSIG2, FAIM2/BCDIN3 and BDNF). In addition, SH2B1 was associated only with class I/II obesity and MC4R only with class III obesity. SNPs located at or near FAIM2/BCDIN3, TMEM18, INSIG2, GNPDA2 and SEC16B/RASAL2 were significantly associated with BMI and/or WC in the combined analysis of Mexican-mestizo children and adults, and FTO locus was significantly associated with increased BMI in Indigenous Mexican populations.

Conclusions

Our findings replicate the association of 8 obesity-related SNPs with obesity risk in Mexican adults, and confirm the role of some of these SNPs in BMI in Mexican adults and children.     

Comparative genome analysis with the human genome reveals chicken genes associated with fatness and body weight

The selection of meat-type chickens (broilers) for rapid growth has been accompanied by excessive fat deposition. In this study, we analysed 53 candidate genes that are associated with obesity and obesity-related traits in humans, for which we found chicken orthologues by BLAST searches. We have identified single nucleotide polymorphisms (SNPs) with significant differences in allele frequencies between broilers and layers in each of the following six candidate genes: adrenergic, beta-2-, receptor, surface (ADRB2); melanocortin 5 receptor (MC5R); leptin receptor (LEPR), McKusick-Kaufman syndrome (MKKS), milk fat globule-EGF factor 8 protein (MFGE8) and adenylate kinase 1 (AK1). To examine associations with fatness and/or body weight, we used birds of extreme phenotypes in F(2) and backcross populations with varying levels of abdominal fat weight per cent (%AFW) and body weight. We then assessed the level of gene expression by real-time PCR. In two genes, ADRB2 and MFGE8, we found significant association with %AFW. The ADRB2 gene was found to have a significantly higher expression in the liver of lean chickens compared with those of the fat individuals. We believe that this approach can be applied for the identification of other quantitative genes.     

Racial differences in measures of obesity and risk of colon adenoma

Obesity is an established risk factor for several malignancies. However, the specific measurement of obesity most relevant to colon neoplasia is still debated, and evidence has suggested gender and racial differences in this measurement. In this study, we sought to compare which measurement--BMI, waist circumference (WC), waist-to-hip ratio (WHR) or waist-to-height ratio (WHtR)--is most strongly associated with development of colon adenomas, a precursor of colon cancer, and to investigate differences in this association between racial groups. We confirmed the strong association between WHR, as a measure of central obesity, and development of colon neoplasia. In our overall analysis, patients in the highest WHR quartile showed a substantial increase in risk of colon adenomas compared to patients in the lowest WHR quartile (odds ratio (OR) = 1.82, 95% confidence interval (CI): 1.12-2.71, P(trend) = 0.0017). In stratified analyses, we noted that strongly associated obesity measures in European Americans were WC (OR = 2.38, 95% CI = 1.45-3.92, P(trend) = 0.0004) and BMI (OR = 2.18, 95% CI = 1.37-3.49, P(trend) = 0.0015), whereas in African Americans, WHR was the strongest and the only obesity measure statistically significantly associated with adenoma risk (OR = 2.12, 95% CI = 1.05-4.30, P(trend) = 0.025). Our data highlight the importance of obesity in the development of early colon neoplasia and suggest substantial racial differences in the measures of obesity most strongly associated with risk of colon adenomas.     

Prevalence of obesity and correlations with lifestyle and dietary factors in Chinese men

Objective: To estimate the age‐adjusted prevalence of general and centralized obesity among Chinese men living in urban Shanghai. Methods and Procedures: A cross‐sectional study was conducted in 61,582 Chinese men aged 40–75. BMI (kg/m²) was used to measure overweight (23 ≤ BMI < 27.4) and obesity (BMI ≥ 27.5) based on the World Health Organization (WHO) recommended criteria for Asians. Waist‐to‐hip ratio (WHR) was used to measure moderate (75th ≤ WHR < 90th percentile) and severe (WHR ≥ 90th percentile) centralized obesity. Results: The average BMI and WHR were 23.7 kg/m² and 0.90, respectively. The prevalence of overweight was 48.6% and obesity was 10.5%. The prevalence of general and centralized obesity was higher in men with high income or who were retired, tea drinkers, or nonusers of ginseng than their counterparts. Men with high education had a higher prevalence of overweight and centralized obesity, but had a lower prevalence of obesity and severe centralized obesity compared to those with less education. Current smokers or alcohol drinkers had a lower prevalence of general obesity but higher prevalence of centralized obesity than nonsmokers or nondrinkers of alcohol. Ex‐smokers and ex‐alcohol drinkers had a higher prevalence of general and centralized obesity compared to nonsmokers and nondrinkers of alcohol. Prevalence of obesity was associated with high energy intake and less daily physical activity. Discussion: The prevalence of obesity among Chinese men in urban Shanghai was lower than that observed in Western countries but higher than that in other Asian countries, and the prevalence of general and centralized obesity differed by demographic, lifestyle, and dietary factors.     

The effect of ponderal index at birth on the relationships between common LEP and LEPR polymorphisms and adiposity in adolescents

This study examined the effect of ponderal index (PI) at birth on the relationships between eight common polymorphisms of the leptin (LEP) and leptin receptor (LEPR) genes and adiposity in adolescents. A total of 823 European adolescents (45.4% girls) aged 14.8 ± 1.4 years were genotyped for the LEP (rs2167270, rs12706832, rs10244329, rs2071045, and rs3828942) and LEPR (rs1137100, rs1137101, and rs8179183) polymorphisms. The PI was calculated from parental reports of birth weight and length. Fat mass index (FMI) was calculated. Analyses were adjusted for relevant confounders. An "adiposity-risk-allele score" based on genotypes at the three single-nucleotide polymorphisms (SNPs) associated with adolescents' FMI in adolescents within the lower tertile of PI was calculated. The LEP rs10244329 and rs3828942 polymorphisms were associated with higher FMI only in adolescents within the lower PI tertile (+0.55 kg/m(2) per minor T allele, P = 0.040, and +0.58 kg/m(2) per major G allele, P = 0.028, respectively). The LEPR rs8179183 polymorphism was significantly associated with higher FMI in adolescents within the lower PI tertile (+0.87 kg/m(2) per minor C allele, P = 0.006). After correction for multiple comparisons, only the association between the LEPR rs8179183 and FMI persisted. However, each additional risk allele conferred 0.53 kg/m(2) greater FMI in adolescents within the lower tertile of PI (P = 0.008). In conclusion, our results suggest that those adolescents born with lower PI could be more vulnerable to the influence of the LEP rs10244329 and rs3828942 polymorphisms and LEPR rs8179183 polymorphism on total adiposity content. Due to the relatively small sample size, these findings should be replicated in further larger population samples.     

A genome-wide association study on obesity and obesity-related traits

Large-scale genome-wide association studies (GWAS) have identified many loci associated with body mass index (BMI), but few studies focused on obesity as a binary trait. Here we report the results of a GWAS and candidate SNP genotyping study of obesity, including extremely obese cases and never overweight controls as well as families segregating extreme obesity and thinness. We first performed a GWAS on 520 cases (BMI>35 kg/m(2)) and 540 control subjects (BMI<25 kg/m(2)), on measures of obesity and obesity-related traits. We subsequently followed up obesity-associated signals by genotyping the top ～500 SNPs from GWAS in the combined sample of cases, controls and family members totaling 2,256 individuals. For the binary trait of obesity, we found 16 genome-wide significant signals within the FTO gene (strongest signal at rs17817449, P = 2.5 × 10(-12)). We next examined obesity-related quantitative traits (such as total body weight, waist circumference and waist to hip ratio), and detected genome-wide significant signals between waist to hip ratio and NRXN3 (rs11624704, P = 2.67 × 10(-9)), previously associated with body weight and fat distribution. Our study demonstrated how a relatively small sample ascertained through extreme phenotypes can detect genuine associations in a GWAS.