Obesity-induced hypoadiponectinaemia: the opposite influences of central and peripheral fat compartments.

Background and Aims: The substantial reduction in adiponectin concentration among obese individuals seems to depend on fat distribution and is a marker of metabolic and adipose tissue dysfunction. We aimed to: (i) address whether abdominal fat from different compartments (visceral, deep subcutaneous abdominal and superficial subcutaneous abdominal) and gluteofemoral fat are independently associated with blood adiponectin concentration; and (ii) investigate whether abdominal (proxied by waist circumference) and gluteofemoral fat (proxied by hip circumference) accumulation causally determine blood adiponectin concentration. Methods: To investigate the independent association of abdominal and gluteofemoral fat with adiponectin concentration, we used multivariable regression and data from 30-year-old adults from the 1982 Pelotas Birth Cohort (n = 2,743). To assess the causal role of abdominal and gluteofemoral fat accumulation on adiponectin concentration, we used Mendelian randomization and data from two consortia of genome-wide association studies-the GIANT (n > 210 000) and ADIPOGen consortia (n = 29 347). Results: In the multivariable regression analysis, all abdominal fat depots were negatively associated with adiponectin concentration, specially visceral abdominal fat [men: ß = -0.24 standard unit of log adiponectin per standard unit increase in abdominal fat; 95% confidence interval (CI) = -0.31, -0.18; P = 8*10-13; women: ß = -0.31; 95% CI = -0.36, -0.25; P = 7*10-27), whereas gluteofemoral fat was positively associated with adiponectin concentration (men: ß = 0.13 standard unit of log adiponectin per standard unit increase in gluteofemoral fat; 95% CI = 0.03, 0.22; P = 0.008; women: ß = 0.24; 95% CI = 0.17, 0.31; P = 7*10-11). In the Mendelian randomization analysis, genetically-predicted waist circumference was inversely related to blood adiponectin concentration (ß = -0.27 standard unit of log adiponectin per standard unit increase in waist circumference; 95% CI = -0.36, -0.19; P = 2*10-11), whereas genetically-predicted hip circumference was positively associated with blood adiponectin concentration (ß = 0.17 standard unit of log adiponectin per standard unit increase in hip circumference; 95% CI = 0.11, 0.24; P = 1*10-7). Conclusions: These results support the hypotheses that there is a complex interplay between body fat distribution and circulating adiponectin concentration, and that whereas obesity-induced hypoadiponectinaemia seems to be primarily attributed to abdominal fat accumulation, gluteofemoral fat accumulation is likely to exert a protective effect.

Interactions between lifestyle and MTHFR polymorphisms on homocysteine concentrations in young adults belonging to the 1982 Pelotas Birth Cohort.

BACKGROUND/OBJECTIVES: Homocysteine (Hcy) is a key intermediate in methionine metabolism. A high plasma concentration of Hcy is an independent risk factor for cardiovascular diseases among other determinants. In this study, we aimed to investigate the interactions between methylenetetrahydrofolate reductase enzyme gene (MTHFR) polymorphisms and lifestyle variables (smoking, alcohol intake and physical activity) on Hcy concentrations in a young Brazilian population. SUBJECTS/METHODS: The study population comprised 3803 individuals from the Pelotas Birth Cohort, aged 22-23 years. Allelic discrimination assays and chemiluminescence immunoassays were performed for genotyping and serum Hcy measurements, respectively. Linear regression models were used to explore the effect of gene-lifestyle interactions on Hcy concentrations. RESULTS: Men carrying the MTHFR 677TT genotype, who were also smokers and drinkers (⩾15 g of alcohol per day), had the highest concentration of Hcy (P-value for the interaction <0.001 for smoking and 0.002 for alcohol intake). In contrast, high folate concentrations attenuated the effects of the MTHFR C677T genotype on serum Hcy concentrations (P-value for interaction <0.001). Also, among males, blood folate concentration was the only lifestyle variable able to modify the influence of MTHFR A1298C genotypes on Hcy concentrations (P-value for the interaction <0.001). There was no strong evidence of an interaction between the MTHFR genotypes and the lifestyle variables in women. CONCLUSIONS: In summary, our study demonstrates a sex difference in Hcy concentrations among Brazilian young adults regarding MTHFR C677T-lifestyle interactions that are worsened under conditions of low blood folate. Identification of potentially modifiable factors related to an increase in homocysteine in young adults, especially in those who are genetically susceptible, is important to prevent negative health consequences in the future.

Haplotype TGTG from SNP 45T/G and 276G/T of the adiponectin gene contributes to risk of polycystic ovary syndrome.

BACKGROUND: Haplotypes of adiponectin gene single nucleotide polymorphisms (SNP) might be related to metabolic disorders. AIM: To assess whether the prevalence of SNP 45T/G and 276G/T of the adiponectin gene and their haplotypes differ between polycystic ovary syndrome (PCOS) and non-hirsute cycling controls and to investigate the relationship between these haplotypes and risk factors for cardiovascular disease. SUBJECTS AND METHODS: In this case-control study, 80 women with PCOS and 1500 non-hirsute controls with regular cycles underwent clinical and laboratory measurements. Genotype distribution was analyzed by conventional PCR-restriction fragment length polymorphism. RESULTS: Compared to controls, PCOS women had greater body mass index (BMI) (31.0±7.9 kg/m² vs 23.4±4.6 kg/m²; p<0.001), waist circumference (92.2±18.8 cm vs 74.5±10.2 cm; p<0.001), and systolic and diastolic blood pressure (124.6±19.9 vs 111.5±13.0 mmHg and 79.2±12.5 vs 71.8±10.6 mmHg; p<0.025), as well as a worse lipid profile (p<0.007), even after adjustment for age and BMI. Genotype distribution was similar in PCOS and controls (45T/G: p=0.399; 276G/T: p=0.135). Six haplotypes were inferred and their frequencies differed significantly between the groups (p=0.001). The TGTG haplotype was more frequent in PCOS than controls (41.3 vs 18.9%). In PCOS, the GG genotype for SNP 276 (p=0.031) and the TGTG haplotype (p=0.023) were associated with higher systolic blood pressure vs other genotypes and haplotypes. Body composition, glucose, insulin, and lipid profile were similar across genotypes and haplotypes in both groups. CONCLUSIONS: Haplotype TGTG from adiponectin gene variants 45T/G and 276G/T is related to susceptibility to PCOS, and might be associated with increased blood pressure in PCOS.

Correlates of C-reactive protein levels in young adults: a population-based cohort study of 3827 subjects in Brazil.

The socio-demographic, behavioral and anthropometric correlates of C-reactive protein levels were examined in a representative young adult Brazilian population. The 1982 Pelotas Birth Cohort Study (Brazil) recruited over 99% of births in the city of Pelotas that year (N = 5914). Individuals belonging to the cohort have been prospectively followed up. In 2004-2005, 77.4% of the cohort was traced, members were interviewed and 3827 individuals donated blood. Analyses of the outcome were based on a conceptual model that differentiated confounders from potential mediators. The following independent variables were studied in relation to levels of C-reactive protein in sex-stratified analyses: skin color, age, family income, education, parity, body mass index, waist circumference, smoking, fat/fiber/alcohol intake, physical activity, and minor psychiatric disorder. Geometric mean (95% confidence interval) C-reactive protein levels for the 1919 males and 1908 females were 0.89 (0.84-0.94) and 1.96 mg/L (1.85-2.09), respectively. Pregnant women and those using oral contraceptive therapies presented the highest C-reactive protein levels and all sub-groups of women had higher levels than men (P < 0.001). Significant associations between C-reactive protein levels were observed with age, socioeconomic indicators, obesity status, smoking, fat and alcohol intake, and minor psychiatric disorder. Associations were stronger at higher levels of C-reactive protein and some associations were sex-specific. We conclude that both distal (socio-demographic) and proximal (anthropometric and behavioral) factors exert strong effects on C-reactive protein levels and that the former are mediated to some degree by the latter.

Correlates of C-reactive protein levels in young adults: a population-based cohort study of 3827 subjects in Brazil

The socio-demographic, behavioral and anthropometric correlates of C-reactive protein levels were examined in a representative young adult Brazilian population. The 1982 Pelotas Birth Cohort Study (Brazil) recruited over 99 percent of births in the city of Pelotas that year (N = 5914). Individuals belonging to the cohort have been prospectively followed up. In 2004-2005, 77.4 percent of the cohort was traced, members were interviewed and 3827 individuals donated blood. Analyses of the outcome were based on a conceptual model that differentiated confounders from potential mediators. The following independent variables were studied in relation to levels of C-reactive protein in sex-stratified analyses: skin color, age, family income, education, parity, body mass index, waist circumference, smoking, fat/fiber/alcohol intake, physical activity, and minor psychiatric disorder. Geometric mean (95 percent confidence interval) C-reactive protein levels for the 1919 males and 1908 females were 0.89 (0.84-0.94) and 1.96 mg/L (1.85-2.09), respectively. Pregnant women and those using oral contraceptive therapies presented the highest C-reactive protein levels and all sub-groups of women had higher levels than men (P < 0.001). Significant associations between C-reactive protein levels were observed with age, socioeconomic indicators, obesity status, smoking, fat and alcohol intake, and minor psychiatric disorder. Associations were stronger at higher levels of C-reactive protein and some associations were sex-specific. We conclude that both distal (socio-demographic) and proximal (anthropometric and behavioral) factors exert strong effects on C-reactive protein levels and that the former are mediated to some degree by the latter.

The 5alpha-reductase type 1, but not type 2, gene is expressed in anagen hairs plucked from the vertex area of the scalp of hirsute women and normal individuals

The aim of the present study was to determine the expression of the genes for type 1 (SDR5A1) and type 2 (SDR5A2) 5alpha-reductase isoenzymes in scalp hairs plucked from 33 hirsute patients (20 with polycystic ovary syndrome and 13 with idiopathic hirsutism) and compare it with that of 10 men and 15 normal women. SDR5A1 and SDR5A2 expression was estimated by RT-PCR using the gene of the ubiquitously expressed protein ß2-microglobulin as an internal control. The results are expressed as arbitrary units in relation to ß2-microglobulin absorbance (mean ± SEM). SDR5A2 expression was not detected in any hair samples analyzed in this study. No differences were found in SDR5A1 mRNA levels between men and normal women (0.78 ± 0.05 vs 0.74 ± 0.06, respectively). SDR5A1 gene expression in the cells of hair plucked from the scalp of normal women (0.85 ± 0.04) and of women with polycystic ovary syndrome (0.78 ± 0.05) and idiopathic hirsutism (0.80 ± 0.06) was also similar. These results indicate that SDR5A1 gene expression in the follicular keratinocytes from the vertex area of the scalp seems not to be related to the differences in hair growth observed between normal men and women and hirsute patients. Further studies are needed to investigate the expression of the 5alpha-reductase genes in other scalp follicular compartments such as dermal papillae, and also in hair follicles from other body sites, in order to elucidate the mechanism of androgen action on the hair growth process and related diseases

The 5alpha-reductase type 1, but not type 2, gene is expressed in anagen hairs plucked from the vertex area of the scalp of hirsute women and normal individuals.

The aim of the present study was to determine the expression of the genes for type 1 (SDR5A1) and type 2 (SDR5A2) 5alpha-reductase isoenzymes in scalp hairs plucked from 33 hirsute patients (20 with polycystic ovary syndrome and 13 with idiopathic hirsutism) and compare it with that of 10 men and 15 normal women. SDR5A1 and SDR5A2 expression was estimated by RT-PCR using the gene of the ubiquitously expressed protein 2-microglobulin as an internal control. The results are expressed as arbitrary units in relation to beta2-microglobulin absorbance (mean SEM). SDR5A2 expression was not detected in any hair samples analyzed in this study. No differences were found in SDR5A1 mRNA levels between men and normal women (0.78+/-0.05 vs 0.74+/-0.06, respectively). SDR5A1 gene expression in the cells of hair plucked from the scalp of normal women (0.85+/-0.04) and of women with polycystic ovary syndrome (0.78+/-0.05) and idiopathic hirsutism (0.80+/-0.06) was also similar. These results indicate that SDR5A1 gene expression in the follicular keratinocytes from the vertex area of the scalp seems not to be related to the differences in hair growth observed between normal men and women and hirsute patients. Further studies are needed to investigate the expression of the 5alpha-reductase genes in other scalp follicular compartments such as dermal papillae, and also in hair follicles from other body sites, in order to elucidate the mechanism of androgen action on the hair growth process and related diseases.