A Randomized Comparison of Postprandial Glucose Excursion Using Inhaled Insulin Versus Rapid-Acting Analog Insulin in Adults With Type 1 Diabetes Using Multiple Daily Injections of Insulin or Automated Insulin Delivery.

OBJECTIVE: To compare postprandial glucose excursions following a bolus with inhaled technosphere insulin (TI) or subcutaneous rapid-acting analog (RAA) insulin. RESEARCH DESIGN AND METHODS: A meal challenge was completed by 122 adults with type 1 diabetes who were using multiple daily injections (MDI), a nonautomated pump, or automated insulin delivery (AID) and who were randomized to bolus with their usual RAA insulin (n = 61) or TI (n = 61). RESULTS: The primary outcome, the treatment group difference in area under the curve for glucose >180 mg/dL over 2 h, was less with TI versus RAA (adjusted difference -12 mg/dL, 95% CI -22 to -2, P = 0.02). With TI, the glucose excursion was smaller (P = 0.01), peak glucose lower (P = 0.01), and time to peak glucose shorter (P = 0.006). Blood glucose <70 mg/dL occurred in one participant in each group. CONCLUSIONS: Postmeal glucose excursion was smaller with TI than with RAA insulin in a cohort that included both AID and MDI users.

Glycemic Control Predicts Severity of Hepatocyte Ballooning and Hepatic Fibrosis in Nonalcoholic Fatty Liver Disease.

BACKGROUND AND AIMS: Whether glycemic control, as opposed to diabetes status, is associated with the severity of NAFLD is open for study. We aimed to evaluate whether degree of glycemic control in the years preceding liver biopsy predicts the histological severity of NASH. APPROACH AND RESULTS: Using the Duke NAFLD Clinical Database, we examined patients with biopsy-proven NAFLD/NASH (n = 713) and the association of liver injury with glycemic control as measured by hemoglobin A1c (HbA1c). The study cohort was predominantly female (59%) and White (84%) with median (interquartile range) age of 50 (42, 58) years; 49% had diabetes (n = 348). Generalized linear regression models adjusted for age, sex, race, diabetes, body mass index, and hyperlipidemia were used to assess the association between mean HbA1c over the year preceding liver biopsy and severity of histological features of NAFLD/NASH. Histological features were graded and staged according to the NASH Clinical Research Network system. Group-based trajectory analysis was used to examine patients with at least three HbA1c (n = 298) measures over 5 years preceding clinically indicated liver biopsy. Higher mean HbA1c was associated with higher grade of steatosis and ballooned hepatocytes, but not lobular inflammation. Every 1% increase in mean HbA1c was associated with 15% higher odds of increased fibrosis stage (OR, 1.15; 95% CI, 1.01, 1.31). As compared with good glycemic control, moderate control was significantly associated with increased severity of ballooned hepatocytes (OR, 1.74; 95% CI, 1.01, 3.01; P = 0.048) and hepatic fibrosis (HF; OR, 4.59; 95% CI, 2.33, 9.06; P < 0.01). CONCLUSIONS: Glycemic control predicts severity of ballooned hepatocytes and HF in NAFLD/NASH, and thus optimizing glycemic control may be a means of modifying risk of NASH-related fibrosis progression.

Genetic Determinants of Circulating Estrogen Levels and Evidence of a Causal Effect of Estradiol on Bone Density in Men.

Context: Serum estradiol (E2) and estrone (E1) levels exhibit substantial heritability. Objective: To investigate the genetic regulation of serum E2 and E1 in men. Design, Setting, and Participants: Genome-wide association study in 11,097 men of European origin from nine epidemiological cohorts. Main Outcome Measures: Genetic determinants of serum E2 and E1 levels. Results: Variants in/near CYP19A1 demonstrated the strongest evidence for association with E2, resolving to three independent signals. Two additional independent signals were found on the X chromosome; FAMily with sequence similarity 9, member B (FAM9B), rs5934505 (P = 3.4 × 10-8) and Xq27.3, rs5951794 (P = 3.1 × 10-10). E1 signals were found in CYP19A1 (rs2899472, P = 5.5 × 10-23), in Tripartite motif containing 4 (TRIM4; rs17277546, P = 5.8 × 10-14), and CYP11B1/B2 (rs10093796, P = 1.2 × 10-8). E2 signals in CYP19A1 and FAM9B were associated with bone mineral density (BMD). Mendelian randomization analysis suggested a causal effect of serum E2 on BMD in men. A 1 pg/mL genetically increased E2 was associated with a 0.048 standard deviation increase in lumbar spine BMD (P = 2.8 × 10-12). In men and women combined, CYP19A1 alleles associated with higher E2 levels were associated with lower degrees of insulin resistance. Conclusions: Our findings confirm that CYP19A1 is an important genetic regulator of E2 and E1 levels and strengthen the causal importance of E2 for bone health in men. We also report two independent loci on the X-chromosome for E2, and one locus each in TRIM4 and CYP11B1/B2, for E1.

Rare coding variants and X-linked loci associated with age at menarche.

More than 100 loci have been identified for age at menarche by genome-wide association studies; however, collectively these explain only ∼3% of the trait variance. Here we test two overlooked sources of variation in 192,974 European ancestry women: low-frequency protein-coding variants and X-chromosome variants. Five missense/nonsense variants (in ALMS1/LAMB2/TNRC6A/TACR3/PRKAG1) are associated with age at menarche (minor allele frequencies 0.08-4.6%; effect sizes 0.08-1.25 years per allele; P<5 × 10(-8)). In addition, we identify common X-chromosome loci at IGSF1 (rs762080, P=9.4 × 10(-13)) and FAAH2 (rs5914101, P=4.9 × 10(-10)). Highlighted genes implicate cellular energy homeostasis, post-transcriptional gene silencing and fatty-acid amide signalling. A frequently reported mutation in TACR3 for idiopathic hypogonatrophic hypogonadism (p.W275X) is associated with 1.25-year-later menarche (P=2.8 × 10(-11)), illustrating the utility of population studies to estimate the penetrance of reportedly pathogenic mutations. Collectively, these novel variants explain ∼0.5% variance, indicating that these overlooked sources of variation do not substantially explain the 'missing heritability' of this complex trait.

Effects of Testosterone Administration for 3 Years on Subclinical Atherosclerosis Progression in Older Men With Low or Low-Normal Testosterone Levels: A Randomized Clinical Trial.

IMPORTANCE: Testosterone use in older men is increasing, but its long-term effects on progression of atherosclerosis are unknown. OBJECTIVE: To determine the effect of testosterone administration on subclinical atherosclerosis progression in older men with low or low-normal testosterone levels. DESIGN, SETTING, AND PARTICIPANTS: Testosterone's Effects on Atherosclerosis Progression in Aging Men (TEAAM) was a placebo-controlled, double-blind, parallel-group randomized trial involving 308 men 60 years or older with low or low-normal testosterone levels (100-400 ng/dL; free testosterone <50 pg/mL), recruited at 3 US centers. Recruitment took place between September 2004 and February 2009; the last participant completed the study in May 2012. INTERVENTIONS: One hundred fifty-six participants were randomized to receive 7.5 g of 1% testosterone and 152 were randomized to receive placebo gel packets daily for 3 years. The dose was adjusted to achieve testosterone levels between 500 and 900 ng/dL. MAIN OUTCOMES AND MEASURES: Coprimary outcomes included common carotid artery intima-media thickness and coronary artery calcium; secondary outcomes included sexual function and health-related quality of life. RESULTS: Baseline characteristics were similar between groups: patients were a mean age of 67.6 years; 42% had hypertension; 15%, diabetes; 15%, cardiovascular disease; and 27%, obesity. The rate of change in intima-media thickness was 0.010 mm/year in the placebo group and 0.012 mm/year in the testosterone group (mean difference adjusted for age and trial site, 0.0002 mm/year; 95% CI, -0.003 to 0.003, P = .89). The rate of change in the coronary artery calcium score was 41.4 Agatston units/year in the placebo group and 31.4 Agatston units/year in the testosterone group (adjusted mean difference, -10.8 Agatston units/year; 95% CI, -45.7 to 24.2; P = .54). Changes in intima-media thickness or calcium scores were not associated with change in testosterone levels among individuals assigned to receive testosterone. Sexual desire, erectile function, overall sexual function scores, partner intimacy, and health-related quality of life did not differ significantly between groups. Hematocrit and prostate-specific antigen levels increased more in testosterone group. CONCLUSIONS AND RELEVANCE: Among older men with low or low-normal testosterone levels, testosterone administration for 3 years vs placebo did not result in a significant difference in the rates of change in either common carotid artery intima-media thickness or coronary artery calcium nor did it improve overall sexual function or health-related quality of life. Because this trial was only powered to evaluate atherosclerosis progression, these findings should not be interpreted as establishing cardiovascular safety of testosterone use in older men. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00287586.

Association of sex hormones, aging, and atrial fibrillation in men: the Framingham Heart Study.

BACKGROUND: Endogenous sex hormones have been related to cardiovascular outcomes and mortality. We hypothesized that sex hormones are related to atrial fibrillation (AF) in a community-based cohort of middle-aged to older men. METHODS AND RESULTS: We examined testosterone, estradiol, and dehydroepiandrosterone sulfate in relation to incident AF in men participating in the Framingham Heart Study. We assessed the 10-year risk of AF in multivariable-adjusted hazard models. The cohort consisted of 1251 men (age, 68.0±8.2 years), of whom 275 developed incident AF. We identified a significant interaction between age and testosterone and, therefore, stratified men into age 55 to 69 years (n=786), 70 to 79 years (n=351), and ≥80 years (n=114). In men aged 55 to 69 years, each 1 SD decrease in testosterone was associated with hazard ratio (HR) 1.30 (95% confidence interval [CI], 1.07-1.59) for incident AF. The association between testosterone and 10-year incident AF in men 70 to 79 years did not reach statistical significance. In men≥80 years, a 1 SD decrease in testosterone was associated with HR 3.53 (95% CI, 1.96-6.37) for AF risk. Estradiol was associated with incident AF (HR, 1.12; 95% CI, 1.01-1.26). Dehydroepiandrosterone sulfate had a borderline association with risk of AF that was not statistically significant (HR, 1.12; 95% CI, 0.99-1.28). CONCLUSIONS: Testosterone and estradiol are associated with incident AF in a cohort of older men. Testosterone deficiency in men≥80 years is strongly associated with AF risk. The clinical and electrophysiological mechanisms underlying the associations between sex hormones and AF in older men merit continued investigation.

Practice Patterns in Screening for Metabolic Disease in Women with PCOS of Diverse Race-Ethnic Backgrounds.

OBJECTIVES: Women with polycystic ovary syndrome (PCOS) are at high risk for metabolic disorders, which prompted the American Association of Clinical Endocrinologists (AACE) to publish a 2005 position statement recommending screening for metabolic disease.The purposes of the present study were to 1) to examine changes in screening rates for obesity, type 2 diabetes (T2D), metabolic syndrome (MetS), hyperlipidemia (HL), nonalcoholic fatty liver disease (NAFLD), and hypertension (HTN) in women with PCOS after publication of the 2005 AACE position statement and 2) to determine if screening rates and metabolic disorders vary by race-ethnicity. METHODS: PCOS cases in 2006 (n = 547) and 2011 (n = 1,159) and metabolic disorders were identified by International Classification of Diseases, 9th revision (ICD9) code. Screening rates for metabolic disorders were determined by the presence of blood tests (hemoglobin A1c [HbA1c], lipid profile, alanine aminotransferase/aspartate aminotransferase [ALT/AST]). RESULTS: In 2006, ≤25% of PCOS patients underwent recommended screening tests: HbA1c 18%; lipid profile <20%; ALT/AST ≤25%. By 2011, only HbA1c testing had increased (18% to 21%). Obesity increased from 35% to 40%, while other metabolic disorders remained stable. Black women had the highest rates of obesity and HTN in 2011 (Obesity: Black 48%, Hispanic 44%, White 33%, Other 31%, P<.0001; HTN: Black 18%, Hispanic 9%, White 10%, Other 7%, P<.0001). Blacks and Hispanics were screened more often with ALT/AST testing (Black 27/27%, Hispanic 28/27%, White 23/22%, Other 17/18%, P = .02/.03). Screening rates were higher in the endocrine clinic for all metabolic disorders than in other clinics (P<.05). CONCLUSION: Despite the publication of recommendations in 2005, screening rates for metabolic disease in women with PCOS remained low across all race-ethnicities in 2011.

Testosterone with dutasteride, but not anastrazole, improves insulin sensitivity in young obese men: a randomized controlled trial.

INTRODUCTION: Testosterone (T) administration to men increases T, estradiol (E2), dihydrotestosterone (DHT), and fat-free mass (FFM), and decreases fat mass (FM) but does not consistently improve insulin sensitivity (IS). AIM: The aim of this study was to examine the effects of T administration in obese, nondiabetic men on body composition and IS, and to determine if inhibition (i) of metabolism of T to E2 with anastrazole or to DHT with dutasteride alters these effects. METHODS: This was a 98-day randomized, double-blind, parallel group, placebo-controlled trial of 57 men, 24-51 year, free T in the lower 25% of normal range (<0.33 nmol/L), body mass index ≥ 30.0 kg/m(2). Subjects were randomized to one of four groups: (i) placebo: gel, pills, and injection; (ii) T/DHT/iE2: T gel, anastrazole, and acyline (gonadotropin releasing-hormone antagonist to suppress endogenous T); (iii) T/iDHT/E2: T gel, dutasteride, and acyline; (iv) T/DHT/E2: T gel, placebo pills, and acyline. MAIN OUTCOME MEASURES: Main outcome measures are insulin sensitivity as percent change (%Δ) in glucose disposal rates (GDR) from a two-step euglycemic clamp (GDR1 and 2), and %FM and %FFM by dual X-ray absorptiometry scan. RESULTS: Insulin Sensitivity: %Δ GDR1 differed across groups (P = 0.02, anova) and was significantly higher in the dutasteride (T/iDHT/E2) compared with the placebo and T gel (T/DHT/E2) groups. %ΔGDR2 was higher in the dutasteride (T/iDHT/E2) compared with the anastrazole (T/DHT/iE2) group. Body Composition: T gel alone (T/DHT/E2) or with dutasteride (T/iDHT/E2) significantly increased %FFM (P < 0.05) and decreased %FM (P < 0.05). There was no change in %FFM or %FM after placebo or anastrazole (T/DHT/iE2). CONCLUSIONS: The combination of T plus dutasteride improved body composition and IS while T alone improved body composition but not IS, suggesting that when T is administered to men, reduction to DHT attenuates the beneficial effects of aromatization to E2 on IS but not body composition.

Circulating estrone levels are associated prospectively with diabetes risk in men of the Framingham Heart Study.

OBJECTIVE: In postmenopausal women and preclinical murine models, estrogen administration reduces diabetes risk; however, the relationship of estradiol and estrone to diabetes in men is poorly understood. We determined the relationship between circulating estradiol and estrone levels and diabetes risk in community-dwelling men of the Framingham Heart Study (FHS). RESEARCH DESIGN AND METHODS: Cross-sectional relationships of estradiol and estrone levels with diabetes were assessed at examination 7 (1998-2001) in FHS generation 2 men (n = 1,458); prospective associations between hormone levels at examination 7 and incident diabetes were assessed 6.8 years later at examination 8. Type 2 diabetes mellitus was defined as fasting glucose >125 mg/dL, medication use, or both. Estradiol, estrone, and testosterone levels were measured with liquid chromatography-tandem mass spectrometry, and free estradiol and estrone were calculated. RESULTS: In cross-sectional models, men with elevated estrone and estradiol had 40% and 62% increased likelihoods of existing diabetes per cross-sectional doubling of estrone and estradiol levels, respectively. Free estrone (cross-sectional odds ratio 1.28 [95% CI 1.02-1.62], P = 0.04) was associated with impaired fasting glucose at examination 7. There was an increase in risk of existing diabetes with increasing quartiles of total and free estrone and estradiol and an increase in risk of incident diabetes with increasing quartiles of estrone levels. In multivariate longitudinal analyses, a twofold increase in total or free estrone levels at examination 7 was associated with 77 and 93% increases, respectively, in odds of incident diabetes at examination 8. CONCLUSIONS: Although both estradiol and estrone exhibit cross-sectional associations with diabetes in men, in longitudinal analyses estrone is a more sensitive marker of diabetes risk than is estradiol.

A genome-wide association meta-analysis of circulating sex hormone-binding globulin reveals multiple Loci implicated in sex steroid hormone regulation.

Sex hormone-binding globulin (SHBG) is a glycoprotein responsible for the transport and biologic availability of sex steroid hormones, primarily testosterone and estradiol. SHBG has been associated with chronic diseases including type 2 diabetes (T2D) and with hormone-sensitive cancers such as breast and prostate cancer. We performed a genome-wide association study (GWAS) meta-analysis of 21,791 individuals from 10 epidemiologic studies and validated these findings in 7,046 individuals in an additional six studies. We identified twelve genomic regions (SNPs) associated with circulating SHBG concentrations. Loci near the identified SNPs included SHBG (rs12150660, 17p13.1, p = 1.8 × 10(-106)), PRMT6 (rs17496332, 1p13.3, p = 1.4 × 10(-11)), GCKR (rs780093, 2p23.3, p = 2.2 × 10(-16)), ZBTB10 (rs440837, 8q21.13, p = 3.4 × 10(-09)), JMJD1C (rs7910927, 10q21.3, p = 6.1 × 10(-35)), SLCO1B1 (rs4149056, 12p12.1, p = 1.9 × 10(-08)), NR2F2 (rs8023580, 15q26.2, p = 8.3 × 10(-12)), ZNF652 (rs2411984, 17q21.32, p = 3.5 × 10(-14)), TDGF3 (rs1573036, Xq22.3, p = 4.1 × 10(-14)), LHCGR (rs10454142, 2p16.3, p = 1.3 × 10(-07)), BAIAP2L1 (rs3779195, 7q21.3, p = 2.7 × 10(-08)), and UGT2B15 (rs293428, 4q13.2, p = 5.5 × 10(-06)). These genes encompass multiple biologic pathways, including hepatic function, lipid metabolism, carbohydrate metabolism and T2D, androgen and estrogen receptor function, epigenetic effects, and the biology of sex steroid hormone-responsive cancers including breast and prostate cancer. We found evidence of sex-differentiated genetic influences on SHBG. In a sex-specific GWAS, the loci 4q13.2-UGT2B15 was significant in men only (men p = 2.5 × 10(-08), women p = 0.66, heterogeneity p = 0.003). Additionally, three loci showed strong sex-differentiated effects: 17p13.1-SHBG and Xq22.3-TDGF3 were stronger in men, whereas 8q21.12-ZBTB10 was stronger in women. Conditional analyses identified additional signals at the SHBG gene that together almost double the proportion of variance explained at the locus. Using an independent study of 1,129 individuals, all SNPs identified in the overall or sex-differentiated or conditional analyses explained ~15.6% and ~8.4% of the genetic variation of SHBG concentrations in men and women, respectively. The evidence for sex-differentiated effects and allelic heterogeneity highlight the importance of considering these features when estimating complex trait variance.

Meta-analyses identify 13 loci associated with age at menopause and highlight DNA repair and immune pathways.

To newly identify loci for age at natural menopause, we carried out a meta-analysis of 22 genome-wide association studies (GWAS) in 38,968 women of European descent, with replication in up to 14,435 women. In addition to four known loci, we identified 13 loci newly associated with age at natural menopause (at P < 5 × 10(-8)). Candidate genes located at these newly associated loci include genes implicated in DNA repair (EXO1, HELQ, UIMC1, FAM175A, FANCI, TLK1, POLG and PRIM1) and immune function (IL11, NLRP11 and PRRC2A (also known as BAT2)). Gene-set enrichment pathway analyses using the full GWAS data set identified exoDNase, NF-κB signaling and mitochondrial dysfunction as biological processes related to timing of menopause.

Genetic determinants of serum testosterone concentrations in men.

Testosterone concentrations in men are associated with cardiovascular morbidity, osteoporosis, and mortality and are affected by age, smoking, and obesity. Because of serum testosterone's high heritability, we performed a meta-analysis of genome-wide association data in 8,938 men from seven cohorts and followed up the genome-wide significant findings in one in silico (n = 871) and two de novo replication cohorts (n = 4,620) to identify genetic loci significantly associated with serum testosterone concentration in men. All these loci were also associated with low serum testosterone concentration defined as <300 ng/dl. Two single-nucleotide polymorphisms at the sex hormone-binding globulin (SHBG) locus (17p13-p12) were identified as independently associated with serum testosterone concentration (rs12150660, p = 1.2×10(-41) and rs6258, p = 2.3×10(-22)). Subjects with ≥ 3 risk alleles of these variants had 6.5-fold higher risk of having low serum testosterone than subjects with no risk allele. The rs5934505 polymorphism near FAM9B on the X chromosome was also associated with testosterone concentrations (p = 5.6×10(-16)). The rs6258 polymorphism in exon 4 of SHBG affected SHBG's affinity for binding testosterone and the measured free testosterone fraction (p<0.01). Genetic variants in the SHBG locus and on the X chromosome are associated with a substantial variation in testosterone concentrations and increased risk of low testosterone. rs6258 is the first reported SHBG polymorphism, which affects testosterone binding to SHBG and the free testosterone fraction and could therefore influence the calculation of free testosterone using law-of-mass-action equation.

Sex hormone-binding globulin, but not testosterone, is associated prospectively and independently with incident metabolic syndrome in men: the framingham heart study.

OBJECTIVE: The association between total testosterone and metabolic syndrome has prompted speculation that low testosterone contributes to the pathophysiology of metabolic syndrome in men. We determined whether testosterone or sex hormone-binding globulin (SHBG) is independently associated with the risk of metabolic syndrome. RESEARCH DESIGN AND METHODS: Cross-sectional relationships of hormone levels with metabolic syndrome were assessed in a sample of men in generation 2 of the Framingham Heart Study (FHS) who did not receive testosterone or androgen-deprivation therapy (n = 1,625) and confirmed in a validation sample of men in FHS generation 3 (n = 1,912). Hormone levels in generation 2 examination 7 were related prospectively to incident metabolic syndrome 6.6 years later at examination 8. Testosterone was measured using liquid chromatography-tandem mass spectrometry, SHBG was measured by immunofluorometric assay, and free testosterone was calculated. Metabolic syndrome was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria. RESULTS Cross-sectionally, testosterone and SHBG were more strongly associated with metabolic syndrome than free testosterone in the training sample. SHBG, but not testosterone or free testosterone, was significantly associated with metabolic syndrome after adjusting for age, smoking, BMI, and insulin sensitivity (homeostasis model assessment of insulin resistance [HOMA-IR]). These findings were confirmed in a validation sample. Longitudinally, SHBG at examination 7, but not testosterone or free testosterone, was associated with incident metabolic syndrome at examination 8 after adjusting for age, smoking, BMI, and HOMA-IR. Multivariable analyses suggested that age, BMI, and insulin sensitivity independently affect SHBG and testosterone levels and the risk of metabolic syndrome and its components. CONCLUSIONS: SHBG, but not testosterone, is independently associated with the risk of metabolic syndrome. These data do not reveal an independent prospective relationship between testosterone and metabolic syndrome in men.

Relation of visceral adiposity to circulating natriuretic peptides in ambulatory individuals.

Natriuretic peptides have important roles in the regulation of vasomotor tone, salt homeostasis, and ventricular remodeling. Lower natriuretic peptide levels observed in obese individuals may underlie the greater cardiovascular risk associated with obesity. Thus the aim of this study was to determine whether lower natriuretic peptide levels in obesity are attributable to differences in regional fat distribution. We investigated the relation of plasma N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) to regional adiposity in 1,873 community-based individuals (46% women, mean age 45 years). Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) volumes were measured by multidetector computed tomography. In gender-specific multivariable analyses adjusting for age and blood pressure, log NT-pro-BNP was inversely associated with VAT in men (beta -0.11 per standard deviation increment, p <0.001) and women (beta -0.19, p <0.001). Log NT-pro-BNP was inversely associated with SAT in women only (beta -0.14, p <0.001). In models containing VAT and SAT, only VAT was significantly associated with log NT-pro-BNP (men, beta -0.137, p <0.001; women, beta -0.184, p <0.001). VAT remained associated with log NT-pro-BNP even after adjustment for body mass index and waist circumference (beta -0.119, p <0.001) and in analyses restricted to nonobese patients (beta -0.165, p <0.001). Adjustment for insulin resistance attenuated the associations of NT-pro-BNP with VAT and SAT. In conclusion, this study demonstrates that circulating NT-pro-BNP is related to variations in regional and particularly visceral adiposity. These findings suggest that excess visceral adiposity and concomitant hyperinsulinemia may contribute to the natriuretic peptide "deficiency" observed in obesity.

Cardiac natriuretic peptides, obesity, and insulin resistance: evidence from two community-based studies.

BACKGROUND: The natriuretic peptides play an important role in salt homeostasis and blood pressure regulation. It has been suggested that obesity promotes a relative natriuretic peptide deficiency, but this has been a variable finding in prior studies and the cause is unknown. AIM: The aim of this study was to examine the association between obesity and natriuretic peptide levels and evaluate the role of hyperinsulinemia and testosterone as mediators of this interaction. METHODS: We studied 7770 individuals from the Framingham Heart Study (n = 3833, 54% women) and the Malmö Diet and Cancer study (n = 3918, 60% women). We examined the relation of plasma N-terminal pro-B-type natriuretic peptide levels (N-BNP) with obesity, insulin resistance, and various metabolic subtypes. RESULTS: Obesity was associated with 6-20% lower levels of N-BNP (P < 0.001 in Framingham, P = 0.001 in Malmö), whereas insulin resistance was associated with 10-30% lower levels of N-BNP (P < 0.001 in both cohorts). Individuals with obesity who were insulin sensitive had only modest reductions in N-BNP compared with nonobese, insulin-sensitive individuals. On the other hand, individuals who were nonobese but insulin resistant had 26% lower N-BNP in Framingham (P < 0.001) and 10% lower N-BNP in Malmö (P < 0.001), compared with nonobese and insulin-sensitive individuals. Adjustment for serum-free testosterone did not alter these associations. CONCLUSIONS: In both nonobese and obese individuals, insulin resistance is associated with lower natriuretic peptide levels. The relative natriuretic peptide deficiency seen in obesity could be partly attributable to insulin resistance, and could be one mechanism by which insulin resistance promotes hypertension.

Influence of sex and hormone status on circulating natriuretic peptides.

OBJECTIVES: The aim of this study was to assess the relationship between sex hormones and natriuretic peptide levels in community-based adults. BACKGROUND: Women have higher circulating natriuretic peptide concentrations than men, but the mechanisms for these sex-related differences and the impact of hormone therapy are unclear. Experimental studies suggest that androgens may suppress natriuretic peptide secretion. METHODS: We measured N-terminal pro-B-type natriuretic peptide (NT-proBNP), total testosterone, and sex hormone-binding globulin plasma levels in 4,056 men and women (mean age 40 ± 9 years) from the Framingham Heart Study Third-Generation cohort. Sex/hormone status was grouped as: 1) men; 2) post-menopausal women not receiving hormone replacement therapy; 3) pre-menopausal women not receiving hormonal contraceptives; 4) post-menopausal women receiving hormone replacement therapy; and 5) pre-menopausal women receiving hormonal contraceptives. RESULTS: Circulating NT-proBNP levels were associated with sex/hormone status (overall p < 0.0001). Men had lower NT-proBNP levels than women of all menopause or hormone groups, and women receiving hormonal contraceptives had higher NT-proBNP levels than women who were not receiving hormone therapy (all p < 0.0001). These relationships remained significant after adjusting for age, body mass index, and cardiovascular risk factors. Across sex/hormone status groups, free testosterone (FT) levels decreased and sex hormone-binding globulin levels increased in tandem with increasing NT-proBNP levels. In sex-specific analyses, NT-proBNP levels decreased across increasing quartiles of FT in men (p for trend <0.01) and women (p for trend <0.0001). Adjustment for FT markedly attenuated the association between sex/hormone status and NT-proBNP concentrations. CONCLUSIONS: These findings suggest that lower levels of circulating androgens and the potentiating effect of exogenous female hormone therapy contribute to the higher circulating NT-proBNP concentrations in women.

Clinical meaningfulness of the changes in muscle performance and physical function associated with testosterone administration in older men with mobility limitation.

CONTEXT: Testosterone in Older Men with Mobility Limitations Trial determined the effects of testosterone on muscle performance and physical function in older men with mobility limitation. Trial's Data and Safety Monitoring Board recommended enrollment cessation due to increased frequency of adverse events in testosterone arm. The changes in muscle performance and physical function were evaluated in relation to participant's perception of change. METHODS: Men aged 65 years and older, with mobility limitation, total testosterone 100-350 ng/dL, or free testosterone less than 50 pg/mL, were randomized to placebo or 10 g testosterone gel daily for 6 months. Primary outcome was leg-press strength. Secondary outcomes included chest-press strength, stair-climb, 40-m walk, muscle mass, physical activity, self-reported function, and fatigue. Proportions of participants exceeding minimally important difference in study arms were compared. RESULTS: Of 209 randomized participants, 165 had follow-up efficacy measures. Mean (SD) age was 74 (5.4) years and short physical performance battery score 7.7 (1.4). Testosterone arm exhibited greater improvements in leg-press strength, chest-press strength and power, and loaded stair-climb than placebo. Compared with placebo, significantly greater proportion of men receiving testosterone improved their leg-press and chest-press strengths (43% vs 18%, p = .01) and stair-climbing power (28% vs 10%, p = .03) more than minimally important difference. Increases in leg-press strength and stair-climbing power were associated with changes in testosterone levels and muscle mass. Physical activity, walking speed, self-reported function, and fatigue did not change. CONCLUSIONS: Testosterone administration in older men with mobility limitation was associated with patient-important improvements in muscle strength and stair-climbing power. Improvements in muscle strength and only some physical function measures should be weighed against the risk of adverse events in this population.

Eight common genetic variants associated with serum DHEAS levels suggest a key role in ageing mechanisms.

Dehydroepiandrosterone sulphate (DHEAS) is the most abundant circulating steroid secreted by adrenal glands--yet its function is unknown. Its serum concentration declines significantly with increasing age, which has led to speculation that a relative DHEAS deficiency may contribute to the development of common age-related diseases or diminished longevity. We conducted a meta-analysis of genome-wide association data with 14,846 individuals and identified eight independent common SNPs associated with serum DHEAS concentrations. Genes at or near the identified loci include ZKSCAN5 (rs11761528; p = 3.15 × 10(-36)), SULT2A1 (rs2637125; p =  2.61 × 10(-19)), ARPC1A (rs740160; p =  1.56 × 10(-16)), TRIM4 (rs17277546; p =  4.50 × 10(-11)), BMF (rs7181230; p = 5.44 × 10(-11)), HHEX (rs2497306; p =  4.64 × 10(-9)), BCL2L11 (rs6738028; p = 1.72 × 10(-8)), and CYP2C9 (rs2185570; p = 2.29 × 10(-8)). These genes are associated with type 2 diabetes, lymphoma, actin filament assembly, drug and xenobiotic metabolism, and zinc finger proteins. Several SNPs were associated with changes in gene expression levels, and the related genes are connected to biological pathways linking DHEAS with ageing. This study provides much needed insight into the function of DHEAS.

Thirty new loci for age at menarche identified by a meta-analysis of genome-wide association studies.

To identify loci for age at menarche, we performed a meta-analysis of 32 genome-wide association studies in 87,802 women of European descent, with replication in up to 14,731 women. In addition to the known loci at LIN28B (P = 5.4 × 10⁻6°) and 9q31.2 (P = 2.2 × 10⁻³³), we identified 30 new menarche loci (all P < 5 × 10⁻8) and found suggestive evidence for a further 10 loci (P < 1.9 × 10⁻6). The new loci included four previously associated with body mass index (in or near FTO, SEC16B, TRA2B and TMEM18), three in or near other genes implicated in energy homeostasis (BSX, CRTC1 and MCHR2) and three in or near genes implicated in hormonal regulation (INHBA, PCSK2 and RXRG). Ingenuity and gene-set enrichment pathway analyses identified coenzyme A and fatty acid biosynthesis as biological processes related to menarche timing.