Large consortia have revealed hundreds of genetic loci associated with anthropometric traits, one trait at a time. We examined whether genetic variants affect body shape as a composite phenotype that is represented by a combination of anthropometric traits. We developed an approach that calculates averaged PCs (AvPCs) representing body shape derived from six anthropometric traits (body mass index, height, weight, waist and hip circumference, waist-to-hip ratio). The first four AvPCs explain >99% of the variability, are heritable, and associate with cardiometabolic outcomes. We performed genome-wide association analyses for each body shape composite phenotype across 65 studies and meta-analysed summary statistics. We identify six novel loci: LEMD2 and CD47 for AvPC1, RPS6KA5/C14orf159 and GANAB for AvPC3, and ARL15 and ANP32 for AvPC4. Our findings highlight the value of using multiple traits to define complex phenotypes for discovery, which are not captured by single-trait analyses, and may shed light onto new pathways.
Past genome-wide associate studies have identified hundreds of genetic loci that influence body size and shape when examined one trait at a time. Here, Jeff and colleagues develop an aggregate score of various body traits, and use meta-analysis to find new loci linked to body shape.
The growth hormone/insulin‐like growth factor (IGF) axis can be manipulated in animal models to promote longevity, and IGF‐related proteins including IGF‐I and IGF‐binding protein‐3 (IGFBP‐3) have also been implicated in risk of human diseases including cardiovascular diseases, diabetes, and cancer. Through genomewide association study of up to 30 884 adults of European ancestry from 21 studies, we confirmed and extended the list of previously identified loci associated with circulating IGF‐I and IGFBP‐3 concentrations (IGF1, IGFBP3,GCKR,TNS3, GHSR, FOXO3, ASXL2, NUBP2/IGFALS, SORCS2, and CELSR2). Significant sex interactions, which were characterized by different genotype–phenotype associations between men and women, were found only for associations of IGFBP‐3 concentrations with SNPs at the loci IGFBP3 and SORCS2. Analyses of SNPs, gene expression, and protein levels suggested that interplay between IGFBP3 and genes within the NUBP2 locus (IGFALS and HAGH) may affect circulating IGF‐I and IGFBP‐3 concentrations. The IGF‐I‐decreasing allele of SNP rs934073, which is an eQTL of ASXL2, was associated with lower adiposity and higher likelihood of survival beyond 90 years. The known longevity‐associated variant rs2153960 (FOXO3) was observed to be a genomewide significant SNP for IGF‐I concentrations. Bioinformatics analysis suggested enrichment of putative regulatory elements among these IGF‐I‐ and IGFBP‐3‐associated loci, particularly of rs646776 at CELSR2. In conclusion, this study identified several loci associated with circulating IGF‐I and IGFBP‐3 concentrations and provides clues to the potential role of the IGF axis in mediating effects of known (FOXO3) and novel (ASXL2) longevity‐associated loci.
aging; genomewide association study; growth hormone axis; IGF‐I; IGFBP‐3; longevity
We examined the associations of symptoms of sleep-disordered breathing (SDB), which was defined as loud snoring, stopping breathing for a while during sleep, and daytime sleepiness, and insomnia with glucose metabolism and incident type 2 diabetes in older adults.
RESEARCH DESIGN AND METHODS
Between 1989 and 1993, the Cardiovascular Health Study recruited 5,888 participants ≥65 years of age from four U.S. communities. Participants reported SDB and insomnia symptoms yearly through 1989–1994. In 1989–1990, participants underwent an oral glucose tolerance test, from which insulin secretion and insulin sensitivity were estimated. Fasting glucose levels were measured in 1989–1990 and again in 1992–1993, 1994–1995, 1996–1997, and 1998–1999, and medication use was ascertained yearly. We determined the cross-sectional associations of sleep symptoms with fasting glucose levels, 2-h glucose levels, insulin sensitivity, and insulin secretion using generalized estimated equations and linear regression models. We determined the associations of updated and averaged sleep symptoms with incident diabetes in Cox proportional hazards models. We adjusted for sociodemographics, lifestyle factors, and medical history.
Observed apnea, snoring, and daytime sleepiness were associated with higher fasting glucose levels, higher 2-h glucose levels, lower insulin sensitivity, and higher insulin secretion. The risk of the development of type 2 diabetes was positively associated with observed apnea (hazard ratio [HR] 1.84 [95% CI 1.19–2.86]), snoring (HR 1.27 [95% CI 0.95–1.71]), and daytime sleepiness (HR 1.54 [95% CI 1.13–2.12]). In contrast, we did not find consistent associations between insomnia symptoms and glucose metabolism or incident type 2 diabetes.
Easily collected symptoms of SDB are strongly associated with insulin resistance and the incidence of type 2 diabetes in older adults. Monitoring glucose metabolism in such patients may prove useful in identifying candidates for lifestyle or pharmacological therapy. Further studies are needed to determine whether insomnia symptoms affect the risk of diabetes in younger adults.
Sedentary behavior is recognized as a distinct construct from lack of moderate-vigorous physical activity and is associated with deleterious health outcomes. Previous studies have primarily relied on self-reported data, while data on the relationship between objectively-measured sedentary time and cardiometabolic biomarkers are sparse, especially among U.S. Hispanics/Latinos.
Methods and Results
We examined associations of objectively-measured sedentary time (via Actical accelerometers for 7 days) and multiple cardiometabolic biomarkers among 12,083 participants, aged 18–74 years, from the Hispanic Community Health Study/Study of Latinos. Hispanics/Latinos of diverse backgrounds (Central American, Cuban, Dominican, Mexican, Puerto Rican, and South American) were recruited from 4 U.S. cities between 2008 and 2011. Sedentary time (<100 counts/minute) was standardized to 16-hour/day of wear time. The mean sedentary time was 11.9 hours/day (74% of accelerometer wear time). After adjustment for moderate-vigorous physical activity and confounding variables, prolonged sedentary time was associated with decreased high-density lipoprotein (HDL)-cholesterol (P=0.04), and increased triglycerides, 2-hour glucose, fasting insulin and HOMA-IR (all P<0.0001). These associations were generally consistent across age, sex, Hispanic/Latino backgrounds, and physical activity levels. Even among individuals meeting physical activity guidelines, sedentary time was detrimentally associated with several cardiometabolic biomarkers (diastolic blood pressure, HDL-cholesterol, fasting and 2-hour glucose, fasting insulin and HOMA-IR; all P<0.05).
Our large population-based, objectively-derived data showed deleterious associations between sedentary time and cardiometabolic biomarkers, independent of physical activity, in U.S. Hispanics/Latinos. Our findings emphasize the importance of reducing sedentary behavior for the prevention of cardiometabolic diseases, even in those who meet physical activity recommendations.
sedentary behavior; Hispanic; epidemiology; physical exercise; cardiovascular disease risk factors
Human immunodeficiency virus (HIV) infection was associated with greater increases in focal carotid artery plaque over 7 years among both women and men, particularly among those with lower CD4+ counts. Increased plaque was observed even among HIV-infected individuals with persistent virologic suppression.
Background. Individuals infected with human immunodeficiency virus (HIV) live longer as a result of effective treatment, but long-term consequences of infection, treatment, and immunological dysfunction are poorly understood.
Methods. We prospectively examined 1011 women (74% HIV-infected) in the Women's Interagency HIV Study and 811 men (65% HIV-infected) in the Multicenter AIDS Cohort Study who underwent repeated B-mode carotid artery ultrasound imaging in 2004–2013. Outcomes included changes in right common carotid artery intima-media thickness (CCA-IMT) and new focal carotid artery plaque formation (IMT >1.5 mm) over median 7 years. We assessed the association between HIV serostatus and progression of subclinical atherosclerosis, adjusting for demographic, behavioral, and cardiometabolic risk factors.
Results. Unadjusted mean CCA-IMT increased (725 to 752 µm in women, 757 to 790 µm in men), but CCA-IMT progression did not differ by HIV serostatus, either in combined or sex-specific analyses. Focal plaque prevalence increased from 8% to 15% in women and 25% to 34% in men over 7 years. HIV-infected individuals had 1.6-fold greater risk of new plaque formation compared with HIV-uninfected individuals (relative risk [RR] 1.61, 95% CI, 1.12–2.32), adjusting for cardiometabolic factors; the association was similar by sex. Increased plaque occurred even among persistently virologically suppressed HIV-infected individuals compared with uninfected individuals (RR 1.56, 95% CI, 1.07–2.27). HIV-infected individuals with baseline CD4+ ≥500 cells/µL had plaque risk not statistically different from uninfected individuals.
Conclusions. HIV infection is associated with greater increases in focal plaque among women and men, potentially mediated by factors associated with immunodeficiency or HIV replication at levels below current limits of detection.
HIV infection; cardiovascular disease; atherosclerosis; intima-media thickness; viral load
To identify genetic associations with hip osteoarthritis (HOA), we performed a meta-analysis of genome-wide association studies (GWAS) of HOA.
The GWAS meta-analysis included approximately 2.5 million imputed HapMap single nucleotide polymorphisms (SNPs). HOA cases and controls defined radiographically and by total hip replacement were selected from the Osteoporotic Fractures in Men (MrOS) Study and the Study of Osteoporotic Fractures (SOF) (654 cases and 4697 controls, combined). Replication of genome-wide significant SNP associations (P-value ≤ 5x10−8) was examined in five studies (3243 cases and 6891 controls, combined). Functional studies were performed using in vitro models of chondrogenesis and osteogenesis.
The A allele of rs788748, located 65 kb upstream of the IGFBP3 gene, was associated with lower HOA odds at the genome-wide significance level in the discovery stage (OR = 0.71, P-value = 2x10−8). The association replicated in five studies (OR = 0.92, P-value = 0.020), but the joint analysis of discovery and replication results was not genome-wide significant (P-value = 1x10−6). In separate study populations, the rs788748 A allele was also associated with lower circulating IGFBP3 protein levels (P-value = 4x10−13), suggesting that this SNP or a variant in linkage disequilibrium (LD) could be an IGFBP3 regulatory variant. Results from functional studies were consistent with association results. Chondrocyte hypertrophy, a deleterious event in OA pathogenesis, was largely prevented upon IGFBP3 knockdown in chondrocytes. Furthermore, IGFBP3 overexpression induced cartilage catabolism and osteogenic differentiation.
Results from GWAS and functional studies provided suggestive links between IGFBP3 and HOA.
Osteoarthritis of hip; genome-wide association study; functional study; chondrogenesis; IGFBP3
Adipokines and inflammation may provide a mechanistic link between obesity and postmenopausal breast cancer, yet epidemiologic data on their associations with breast cancer risk are limited.
In a case-cohort analysis nested within the Women’s Health Initiative Observational Study, a prospective cohort of postmenopausal women, baseline plasma samples from 875 incident breast cancer case patients and 839 subcohort participants were tested for levels of seven adipokines, namely leptin, adiponectin, resistin, interleukin-6, tumor necrosis factor-α, hepatocyte growth factor, and plasminogen activator inhibitor-1, and for C-reactive protein (CRP), an inflammatory marker. Data were analyzed by multivariable Cox modeling that included established breast cancer risk factors and previously measured estradiol and insulin levels. All statistical tests were two-sided.
The association between plasma CRP levels and breast cancer risk was dependent on hormone therapy (HT) use at baseline (P
interaction = .003). In a model that controlled for multiple breast cancer risk factors including body mass index (BMI), estradiol, and insulin, CRP level was positively associated with breast cancer risk among HT nonusers (hazard ratio for high vs low CRP levels = 1.67, 95% confidence interval = 1.04 to 2.68, P
trend = .029). None of the other adipokines were statistically significantly associated with breast cancer risk. Following inclusion of CRP, insulin, and estradiol in a multivariable model, the association of BMI with breast cancer was attenuated by 115%.
These data indicate that CRP is a risk factor for postmenopausal breast cancer among HT nonusers. Inflammatory mediators, together with insulin and estrogen, may play a role in the obesity–breast cancer relation.
Favorable levels of all readily measurable major cardiovascular disease risk factors (ie, low risk [LR]) are associated with lower risks of cardiovascular disease morbidity and mortality. Data are not available on LR prevalence among Hispanic/Latino adults of diverse ethnic backgrounds. This study aimed to describe the prevalence of a low cardiovascular disease risk profile among Hispanic/Latino adults in the United States and to examine cross‐sectional associations of LR with measures of acculturation.
Methods and Results
The multicenter, prospective, population‐based Hispanic Community Health Study/Study of Latinos examined 16 415 men and women aged 18 to 74 years at baseline (2008–2011) with diverse Hispanic/Latino backgrounds. Analyses involved 14 757 adults (mean age 41.3 years; 60.6% women). LR was defined using national guidelines for favorable levels of serum cholesterol, blood pressure, and body mass index and by not having diabetes mellitus and not currently smoking. Age‐adjusted LR prevalence was low (8.4% overall; 5.1% for men, 11.2% for women) and varied by background (4.2% in men of Mexican heritage versus 15.0% in women of Cuban heritage). Lower acculturation (assessed using proxy measures) was significantly associated with higher odds of a LR profile among women only: Age‐adjusted odds ratios of having LR were 1.64 (95% CI 1.24–2.17) for foreign‐born versus US‐born women and 1.96 (95% CI 1.49–2.58) for women residing in the United States <10 versus ≥10 years.
Among diverse US Hispanic/Latino adults, the prevalence of a LR profile is low. Lower acculturation is associated with higher odds of a LR profile among women but not men. Comprehensive public health strategies are needed to improve the cardiovascular health of US Hispanic/Latino adults.
cardiovascular disease prevention; cardiovascular disease risk factors; low risk; Primary Prevention; Cardiovascular Disease; Race and Ethnicity; Risk Factors
The FTO gene harbors variation with the strongest effect on adiposity and obesity risk. Previous data support a role for FTO variation in influencing food intake. We conducted a combined analysis of 16,094 boys and girls aged 1–18 years from 14 studies to examine the following: 1) the association between the FTO rs9939609 variant (or a proxy) and total energy and macronutrient intake; and 2) the interaction between the FTO variant and dietary intake, and the effect on BMI. We found that the BMI-increasing allele (minor allele) of the FTO variant was associated with increased total energy intake (effect per allele = 14.3 kcal/day [95% CI 5.9, 22.7 kcal/day], P = 6.5 × 10−4), but not with protein, carbohydrate, or fat intake. We also found that protein intake modified the association between the FTO variant and BMI (interactive effect per allele = 0.08 SD [0.03, 0.12 SD], P for interaction = 7.2 × 10−4): the association between FTO genotype and BMI was much stronger in individuals with high protein intake (effect per allele = 0.10 SD [0.07, 0.13 SD], P = 8.2 × 10−10) than in those with low intake (effect per allele = 0.04 SD [0.01, 0.07 SD], P = 0.02). Our results suggest that the FTO variant that confers a predisposition to higher BMI is associated with higher total energy intake, and that lower dietary protein intake attenuates the association between FTO genotype and adiposity in children and adolescents.
US Hispanics/Latinos have high prevalence of obesity and related comorbidities. We compared overall and central obesity measures in associations with cardiometabolic outcomes among US Hispanics/Latinos.
Multivariable regression assessed cross-sectional relationships of six obesity measures with cardiometabolic outcomes among 16,415 Hispanics/Latinos aged 18-74 years.
BMI was moderately correlated with waist-to-hip ratio (WHR; women, r=0.37; men, r=0.58) and highly correlated with other obesity measures (r≥0.87) (P<0.0001). All measures of obesity were correlated with unfavorable levels of glycemic traits, blood pressure, and lipids, with similar r-estimates for each obesity measure (P<0.05). Multivariable-adjusted prevalence ratios (PRs) for diabetes (women, 6.7 [3.9, 11.5]; men, 3.9 [2.2, 6.9]), hypertension (women, 2.4 [1.9, 3.1]; men, 2.5 [1.9, 3.4]), and dyslipidemia (women, 2.1 [1.8, 2.4]; men, 2.2 [1.9, 2.6]) were highest for individuals characterized as overweight/obese (BMI≥25kg/m2) and abnormal WHR (women, ≥0.85; men, ≥0.90), compared to those with normal BMI and WHR (P<0.0001). Among normal-weight individuals, abnormal WHR was associated with increased cardiometabolic condition prevalence (P<0.05), particularly diabetes (women, PR=4.0 [2.2, 7.1]; men, PR=3.0 [1.6, 5.7]).
Obesity measures were associated with cardiometabolic risk factors to a similar degree in US Hispanics/Latinos. WHR is useful to identify individuals with normal BMI at increased cardiometabolic risk.
Hispanics; cardiovascular risk; diabetes; epidemiology; central obesity
To investigate the association between diabetes mellitus and missing teeth in Hispanic/Latino adults from diverse heritage groups who reside in the USA.
Research design and methods
The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) is a multicenter, population-based study of 18–74 years old who underwent a physical and oral examination (n=15 945). Glycemic status was categorized as diabetes, impaired, or normal, based on medication use, and American Diabetes Association criteria for fasting glucose and glycosylated hemoglobin (HbA1c). HbA1c<7% indicated good glycemic control, and HbA1c>7% indicated uncontrolled diabetes. We estimated ORs and 95% CIs for missing >9 teeth and being edentulous (missing all natural teeth), after adjustment for age, income, education, Hispanic background, study site/center, nativity, last dental visit, health insurance, diet quality, cigarette smoking, obesity, periodontitis, and C reactive protein.
Persons with uncontrolled diabetes had a significant increased likelihood of missing >9 teeth and being edentulous as compared with persons with normal glycemic status (adjusted OR=1.92, 95% CI 1.44 to 2.55 and adjusted OR=1.73, 95% CI 1.22 to 2.46, respectively). The association appeared to be stronger at younger ages (18–44 years old; p for interaction <0.0001). However, we found no associations of either impaired glycemia or controlled diabetes with tooth loss in adjusted models.
Dentists should be aware of their Hispanic patients' diabetes status and whether or not they are well controlled, because these may affect tooth loss and impair oral function, which can lead to poor nutrition and complications of diabetes.
Hispanics; Oral and Systemic Health; Adult Diabetes
Little is known about long-term changes in insulin-like growth Factor (IGF) proteins and glycemic status. We hypothesized that changes in IGF proteins are exaggerated in participants with type 2 diabetes or worsening glycemia versus those that remain normoglycemic over a 9-year follow-up period.
Retrospective analysis of cohort study.
Participants were recruited from four States: North Carolina, California, Maryland and Pennsylvania.
897 participants enrolled in CHS All Stars, a cohort study of community dwelling adults aged ≥65 years.
Plasma IGF-I, IGFBP-1, and IGFBP-3 levels were assessed and ADA cut-points for IGT, IFG, and diabetes were used to classify participants at baseline (1996–1997) and follow-up (2005–2006).
At baseline, mean age was 76.3 years (± 3.6) and 18.5% had diabetes. Individuals with IFG alone and IGT+IFG had the highest levels of IGF-I and lowest levels of IGFBP-1, compared to individuals with normoglycemia or diabetes. The greatest percent change in IGF levels occurred in those who had diabetes at baseline (9-year changes: −9.3% for IGF-I, 59.7% for IGFBP-1, −13.4% for IGFBP-3); the smallest in individuals who remained normoglycemic at follow-up (9-year changes: −3.7% for IGF-I, 25.6% for IGFBP-1, −6.4% for IGFBP-3); and intermediate changes in those who were normoglycemic but developed IFG at follow-up.
Our results demonstrate that degrees of glycemic impairment are associated with varying levels of changes in IGF proteins. The exaggerated changes observed in the diabetes group have been previously shown to be associated with heart failure, cancer and non-cancer mortality.
insulin-like growth factor; diabetes; glycemic status
We estimated local ancestry on the autosomes and X chromosome in a large US-based study of 12,793 Hispanic/Latino individuals using the RFMix method, and we compared different reference panels and approaches to local ancestry estimation on the X chromosome by means of Mendelian inconsistency rates as a proxy for accuracy. We developed a novel and straightforward approach to performing ancestry-specific PCA after finding artifactual behavior in the results from an existing approach. Using the ancestry-specific PCA, we found significant population structure within African, European, and Amerindian ancestries in the Hispanic/Latino individuals in our study. In the African ancestral component of the admixed individuals, individuals whose grandparents were from Central America clustered separately from individuals whose grandparents were from the Caribbean, and also from reference Yoruba and Mandenka West African individuals. In the European component, individuals whose grandparents were from Puerto Rico diverged partially from other background groups. In the Amerindian ancestral component, individuals clustered into multiple different groups depending on the grandparental country of origin. Therefore, local ancestry estimation provides further insight into the complex genetic structure of US Hispanic/Latino populations, which must be properly accounted for in genotype-phenotype association studies. It also provides a basis for admixture mapping and ancestry-specific allele frequency estimation, which are useful in the identification of risk factors for disease.
Hispanic/Latino; local ancestry; principal components analysis
Sleep apnea (SA) has been linked with various forms of cardiovascular disease, but little is known about its association with peripheral artery disease (PAD) measured using the ankle- brachial index (ABI). This relationship was evaluated in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).
Approach and Results
We studied 8,367 HCHS/SOL participants who were 45 to 74 years of age. Sleep symptoms were examined with the self-reported Sleep Health Questionnaire. SA was assessed using an in-home sleep study. Systolic blood pressure was measured in all extremities to compute the ABI. PAD was defined as ABI < 0.90 in either leg. Multivariable logistic regression was utilized to investigate the association between moderate-to-severe SA, defined as apnea-hypopnea index (AHI) ≥15, and the presence of PAD. Analyses were adjusted for covariates.
The prevalence of PAD was 4.7% (n=390). The mean AHI was significantly higher among adults with PAD compared to those without (11.1 vs. 8.6 events/hour, p=0.046). After adjusting for covariates, moderate-to-severe SA was associated with a 70% increase in the odds of PAD (odds ratio 1.7, 95% CI: 1.1 – 2.5, p=0.0152). This association was not modified by sex (p=0.8739). However, there was evidence that the association between moderate-to-severe SA and PAD varied by Hispanic/Latino background (p < 0.01). Specifically, the odds were stronger in Mexican (adjusted OR 2.9, 95% CI: 1.3, 6.2) and in Puerto Rican Americans (adjusted OR 2.0, 95% CI: 0.97 – 4.2) than in other backgrounds.
Moderate-to-severe SA is associated with higher odds of PAD in Hispanic/Latino adults.
Sleep apnea; peripheral arterial disease; ankle-brachial index; subclinical atherosclerosis; US Hispanics and Latinos
The study examined the association of childhood and current economic hardship with anthropometric indices in Hispanic/Latino adults, using data from the HCHS/SOL Socio-cultural ancillary study (N = 5,084), a community-based study of Hispanic/Latinos living in four urban areas (Bronx, NY, Chicago, IL, Miami, FL, and San Diego, CA). Childhood economic hardship was defined as having experienced a period of time when one’s family had trouble paying for basic needs (e.g., food, housing), and when this economic hardship occurred: between 0–12, 13–18 years old, or throughout both of those times. Current economic hardship was defined as experiencing trouble paying for basic needs during the past 12 months. Anthropometry included height, body mass index (BMI), waist circumference (WC), and percentage body fat (%BF). Complex survey linear regression models were used to test the associations of childhood economic hardship with adult anthropometric indices, adjusting for potential confounders (e.g., age, sex, Hispanic background). Childhood economic hardship varied by Hispanic background, place of birth, and adult socio-economic status. Childhood economic hardship during both periods, childhood and adolescence, was associated with shorter height. Childhood economic hardship was associated with greater adiposity among US born individuals only. Current economic hardship was significantly associated with all three measures of adiposity (BMI, WC, %BF). These findings suggest that previous periods of childhood economic hardship appear to influence adult height more than adiposity, whereas current economic hardship may be a better determinant of adult adiposity in Hispanics.
hepatitis C virus; macrophage; HIV; FIB-4; sCD14
To increase our understanding of the genetic basis of adiposity and its links to
cardiometabolic disease risk, we conducted a genome-wide association meta-analysis
of body fat percentage (BF%) in up to 100,716 individuals. Twelve loci
reached genome-wide significance (P<5 ×
10−8), of which eight were previously associated with
increased overall adiposity (BMI, BF%) and four (in or near
COBLL1/GRB14, IGF2BP1, PLA2G6, CRTC1) were novel
associations with BF%. Seven loci showed a larger effect on
BF% than on BMI, suggestive of a primary association with adiposity,
while five loci showed larger effects on BMI than on BF%, suggesting
association with both fat and lean mass. In particular, the loci more strongly
associated with BF% showed distinct cross-phenotype association
signatures with a range of cardiometabolic traits revealing new insights in the link
between adiposity and disease risk.
A genome-wide association meta-analysis study here shows novel genetic
loci to be associated to body fat percentage, and describes cross-phenotype association
that further demonstrate a close relationship between adiposity and cardiovascular
The genetic contribution to longevity in humans has been estimated to range from 15% to 25%. Only two genes, APOE and FOXO3, have shown association with longevity in multiple independent studies.
We conducted a meta-analysis of genome-wide association studies including 6,036 longevity cases, age ≥90 years, and 3,757 controls that died between ages 55 and 80 years. We additionally attempted to replicate earlier identified single nucleotide polymorphism (SNP) associations with longevity.
In our meta-analysis, we found suggestive evidence for the association of SNPs near CADM2 (odds ratio [OR] = 0.81; p value = 9.66 × 10−7) and GRIK2 (odds ratio = 1.24; p value = 5.09 × 10−8) with longevity. When attempting to replicate findings earlier identified in genome-wide association studies, only the APOE locus consistently replicated. In an additional look-up of the candidate gene FOXO3, we found that an earlier identified variant shows a highly significant association with longevity when including published data with our meta-analysis (odds ratio = 1.17; p value = 1.85×10−10).
We did not identify new genome-wide significant associations with longevity and did not replicate earlier findings except for APOE and FOXO3. Our inability to find new associations with survival to ages ≥90 years because longevity represents multiple complex traits with heterogeneous genetic underpinnings, or alternatively, that longevity may be regulated by rare variants that are not captured by standard genome-wide genotyping and imputation of common variants.
Longevity; GWAS; FOXO3; APOE.
Hepatitis C virus (HCV) viremia is thought to have broad, systemic effects on the cellular immune system that go beyond its impact on just those T-cells that are HCV-specific. However, prior studies of chronic HCV and circulating T-cell subsets (activation and differentiation phenotypes) in HIV-negatives used general population controls, rather than a risk-appropriate comparison group. Studies in HIV-positives did not address overall immune status (total CD4+ count).
We used fresh blood from HIV-positive and at-risk HIV-negative women, with and without chronic HCV, to measure percentages of activated CD4+ and CD8+ T-cells, Tregs, and T-cell differentiation phenotypes (naïve, central memory (CM), effector memory (EM), and terminally differentiated effector). This included 158 HIV-negatives and 464 HIV-positives, of whom 18 and 63, respectively, were HCV viremic.
In multivariate models of HIV-negatives, HCV viremia was associated with 25% fewer naïve CD4+ (P=0.03), 33% more EM CD4+ (P=0.0002) and 37% fewer CM CD8+ (P=0.02) T-cells. Among HIV-positives we observed only one of these three relationships: higher percentage of EM CD4+ among HCV viremic women. Further, the association with EM CD4+ among HIV-positives was limited to individuals with diminished immune status (total CD4+ count ≤500 cells/μL), as were associations of HCV viremia with higher percentages of activated CD4+ and Tregs. Among HIV-positives with high CD4+ count, no significant associations were observed.
These data suggest that HCV viremia in HIV-negatives is associated with accelerated T-cell differentiation, but among HIV-positives the impact of HCV viremia is less straightforward and varies by total CD4+ count.
hepatitis C virus; HIV; T-cell; phenotype; activation; differentiation
T-cell activation is a major pathway driving HIV disease progression. Little is known regarding the impact of T-cell activation on HIV-associated atherosclerosis and cardiovascular disease, a common co-morbidity in HIV infection. We hypothesized that T-cell activation will predict vascular stiffness, a measure of subclinical atherosclerosis.
Linear regression models evaluated the covariate-adjusted association of T-cell activation with vascular stiffness.
CD38 and HLA-DR expression on CD4+ and CD8+ T-cells was assessed by flow cytometry among 59 HIV-negative and 376 HIV-infected (185 hepatitis-C co-infected) women in the Women's Interagency HIV Study (WIHS). T-cell activation was defined by CD8+CD38+DR+ and CD4+CD38+DR+. Multiple activation assessments over 6.5 years were averaged. In 140 women, T-cell activation was measured before and after HAART initiation. Carotid artery ultrasounds were completed a median of 6.5 years after last measurement of T- cell activation and carotid artery stiffness including distensibility and elasticity were calculated.
Percentages of CD4+ and CD8+ T-cell activation were significantly higher in HIV- infected compared to HIV-negative women. Among HIV-negative women, T-cell activation was not associated with carotid artery stiffness. Among HIV-infected women, higher CD4+ T-cell activation significantly predicted increased arterial stiffness independent of CD4 cell count and HIV RNA. The association was stronger among HIV/HCV co-infected compared to HIV-mono- infected women; however, the difference was not statistically significant (p-for interaction>0.05). Pre- and post-HAART levels of CD4+ T-cell activation significantly predicted carotid artery stiffness.
Persistent T-cell activation, even after HAART initiation, can contribute to structural and/or functional vascular damage accelerating atherogenesis in HIV infection. These results need to be confirmed in a longitudinal prospective study.
T-cell activation; arterial stiffness; HIV-infection
In HIV-negatives, markers of hemostasis including D-dimer, Factor VIII, plasminogen activator inhibitor-1 antigen (PAI-1) and total protein S are associated with all-cause and cardiovascular disease mortality. In HIV-positives, studies of D-dimer and Factor VIII with death were limited to short follow-up; associations of PAI-1 and total protein S with death have not been examined.
In 674 HIV-infected women from the Women’s Interagency HIV Study (WIHS), markers from the first visit after enrollment were exposures of interest in multivariate analyses of death (AIDS and non-AIDS) in separate models at 5 and 16 years.
There were 87 AIDS and 44 non-AIDS deaths at 5 years, and 159 AIDS and 113 non-AIDS deaths at 16 years. An inverse association of total protein S quartiles with non-AIDS deaths was observed at 5 (p-trend=0.002) and 16 years (p-trend=0.02); there was no association with AIDS deaths. The 3rd quartile of PAI-1 was associated with AIDS deaths at 5 (hazard ratio (HR)=4.0, 95% confidence interval (CI)=1.9–8.4) and 16 years (HR=3.4, 95% CI=1.9–5.9); and with non-AIDS deaths at 5 years (HR=4.8, 95%CI=1.6,13.9). D-dimer and Factor VIII were not associated with AIDS or non-AIDS death at 5 or 16 years.
Lower total Protein S was a consistent marker of non-AIDS death. We found no association between D-dimer with AIDS or non-AIDS death, in contrast to previous studies showing increased short term (<5 years) mortality, which may represent sex differences or population heterogeneity. Given longer survival on HAART, further studies of these markers are needed to determine their prognostic value.
One of the main perceived advantages of using a case-cohort design compared to a nested case-control design in an epidemiologic study is the ability to evaluate with the same subcohort outcomes other than the primary outcome of interest. In this paper, we show that valid inferences about secondary outcomes can also be achieved in nested case-control studies by using the inclusion probability weighting method originally proposed by Samuelsen (1997) in combination with an approximate jackknife standard error that can be computed using existing software. Simulation studies demonstrate that when the sample size is sufficient, this approach yields valid type 1 error and coverage rates for the analysis of secondary outcomes in nested case-control designs. Interestingly, the statistical power of the nested case-control design was comparable to that of the case-cohort design when the primary and secondary outcomes were positively correlated. The proposed method is illustrated with data from a cohort in Cardiovascular Health Study to study the association of C-reactive protein levels and the incidence of congestive heart failure.
Incidence density sampling; Nested case-control design; Secondary outcomes
Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age- and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to ~2.8M SNPs with BMI and WHRadjBMI in four strata (men ≤50y, men >50y, women ≤50y, women >50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR<5%) age-specific effects, of which 11 had larger effects in younger (<50y) than in older adults (≥50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.
Adult body size and body shape differ substantially between men and women and change over time. More than 100 genetic variants that influence body mass index (measure of body size) or waist-to-hip ratio (measure of body shape) have been identified. While there is evidence that some genetic loci affect body shape differently in men than in women, little is known about whether genetic effects differ in older compared to younger adults, and whether such changes differ between men and women. Therefore, we conducted a systematic genome-wide search, including 114 studies (>320,000 individuals), to specifically identify genetic loci with age- and or sex-dependent effects on body size and shape. We identified 15 loci of which the effect on BMI was different in older compared to younger adults, whereas we found no evidence for loci with different effects in men compared to women. The opposite was seen for body shape as we identified 44 loci of which the effect on waist-to-hip ratio differed between men and women, but no difference between younger and older adults were observed. Our observations may provide new insights into the biology that underlies weight change with age or the sexual dimorphism of body shape.
Adults infected with HIV have increased atherosclerosis potentially associated with both HIV and non‐HIV associated factors. We characterized risk factors for atherosclerosis as measured by noninvasive vascular imaging.
Methods and Results
We used B‐mode ultrasound to examine levels and correlates of echogenicity and vessel wall thickness of the carotid artery intima‐media complex in 1282 HIV‐infected and 510 HIV‐uninfected women of the Women's Interagency HIV Study. Levels of gray scale median (GSM, a measure of echogenicity) did not vary between HIV infection groups. In both groups, smokers had increased GSM, whereas age, diabetes, elevated blood pressure, and high BMI were associated with lower (rather than higher) GSM. Each of these non‐lipid CVD risk factors, especially age and blood pressure, was also associated with higher levels of carotid artery intima‐media thickness (cIMT). Higher serum triglyceride levels were associated with lower GSM in both HIV‐infected and HIV‐uninfected groups. Additional lipid risk factors for low GSM including high LDL cholesterol and low HDL cholesterol levels were identified in HIV uninfected but not in HIV infected women. In contrast to findings for GSM, among the lipid parameters only LDL cholesterol level had an association with cIMT, which was observed only in the HIV uninfected group.
Lipid and non‐lipid risk factor associations with echolucency of the carotid artery and the thickness of the common carotid artery intima‐media layer suggest that these measures capture different aspects of atherosclerosis.
carotid arteries; epidemiology; immune system; risk factors; ultrasonics