Associations of DNA Base Excision Repair and Antioxidant Enzyme Genetic Risk Scores with Biomarker of Systemic Inflammation

Background: Inflammation is implicated in the etiology of various aging-related diseases. Numerous dietary and lifestyle factors contribute to chronic systemic inflammation; genetic variation may too. However, despite biological plausibility, little is known about associations of antioxidant enzyme (AE) and DNA base excision repair (BER) genotypes with human systemic inflammation. Methods: We genotyped 22 single nucleotide polymorphisms (SNPs) in 3 AE genes, and 79 SNPs in 14 BER genes to develop inflammation-specific AE and BER genetic risk scores (GRS) in two pooled cross-sectional studies (n = 333) of 30-74-year-old White adults without inflammatory bowel disease, familial adenomatous polyposis, or a history of cancer or colorectal adenoma. Of the genotypes, based on their associations with a biomarker of systemic inflammation, circulating high sensitivity C-reactive protein (hsCRP) concentrations, we selected 2 SNPs of 2 genes (CAT and MnSoD) for an AE GRS, and 7 SNPs of 5 genes (MUTYH, SMUG1, TDG, UNG, and XRCC1) for a BER GRS. A higher GRS indicates a higher balance of variant alleles directly associated with hsCRP relative to variant alleles inversely associated with hsCRP. We also calculated previously-reported, validated, questionnaire-based dietary (DIS) and lifestyle (LIS) inflammation scores. We used multivariable general linear regression to compare mean hsCRP concentrations across AE and BER GRS categories, individually and jointly with the DIS and LIS. Results: The mean hsCRP concentrations among those in the highest relative to the lowest AE and BER GRS categories were, proportionately, 13.9% (p = 0.30) and 57.4% (p = 0.009) higher. Neither GRS clearly appeared to modify the associations of the DIS or LIS with hsCRP. Conclusion: Our findings suggest that genotypes of DNA BER genes collectively may be associated with systemic inflammation in humans.

Gene expression of oxidative stress markers and lung function: A CARDIA lung study

BACKGROUND

Circulating markers of oxidative stress have been associated with lower lung function. Our objective was to study the association of gene expression levels of oxidative stress pathway genes (ALOX12, ALOX15, ARG2, GSTT1, LPO, MPO, NDUFB3, PLA2G7, and SOD3) and lung function forced expiratory volume in one second (FEV1 ), forced vital capacity (FVC) in Coronary Artery Risk Development in Young Adults study.

METHODS

Lung function was measured using spirometry and the Nanostring platform was used to estimate gene expression levels. Linear regression models were used to study association of lung function measured at year 30, 10-year decline in lung function and gene expression after adjustment for center, smoking, and BMI, measured at year 25.

RESULTS

The 10-year decline of FEV1 was faster in highest NDUFB3 quartile compared to the lowest (difference = -2.09%; p = 0.001) after adjustment for multiple comparisons. The 10-year decline in FEV1 and FVC was nominally slower in highest versus lowest quartile of PLA2G7 (difference = 1.14%; p = 0.02, and difference = 1.06%; p = 0.005, respectively). The other genes in the study were not associated with FEV1 or FVC.

CONCLUSION

Higher gene expression levels in oxidative stress pathway genes are associated with faster 10-year FEV1 decline.

Serum Urate Trajectory in Young Adulthood and Incident Cardiovascular Disease Events by Middle Age: CARDIA Study

[Figure: see text].

Cardiovascular Health Trajectories and Elevated C-Reactive Protein: The CARDIA Study

Background

The relationship between long‐term cardiovascular health (CVH) patterns and elevated CRP (C‐reactive protein) in late middle age has yet to be investigated. We aimed to assess this relationship.

Methods and Results

Individual CVH components were measured in 4405 Black and White men and women (aged 18–30 years at baseline) in the CARDIA (Coronary Artery Risk Development in Young Adults) study at 8 examinations over 25 years. CRP was measured at 4 examinations (years 7, 15, 20, and 25). Latent class modeling was used to identify individuals with similar trajectories in CVH from young adulthood to middle age. Multivariable Poisson regression models were used to assess the association between race‐specific CVH trajectories and prevalence of elevated CRP levels (>3.0 mg/L) after 25 years of follow‐up. Five distinct CVH trajectories were identified for each race. Lower and decreasing trajectories had higher prevalence of elevated CRP relative to the highest trajectory. Prevalence ratios for elevated CRP in lowest trajectory groups at year 25 were 2.58 (95% CI, 1.89–3.51) and 7.20 (95% CI, 5.09–10.18) among Black and White people, respectively. Prevalence ratios for chronically elevated CRP (elevated CRP at 3 or more of the examinations) in the lowest trajectory groups were 8.37 (95% CI, 4.37–16.00) and 15.89 (95% CI, 9.01–28.02) among Black and White people, respectively.

Conclusions

Lower and decreasing CVH trajectories are associated with higher prevalence of elevated CRP during the transition from young adulthood to middle age.

Dietary and plasma carotenoids are positively associated with alpha diversity in the fecal microbiota of pregnant women

Because microbes use carotenoids as an antioxidant for protection, dietary carotenoids could be associated with gut microbiota composition. We aimed to determine associations among reported carotenoid intake, plasma carotenoid concentrations, and fecal bacterial communities in pregnant women. Pregnant women (n = 27) were enrolled in a two-arm study designed to assess feasibility of biospecimen collection and delivery of a practical nutrition intervention. Plasma and fecal samples were collected and women were surveyed with a 24-hr dietary checklist and recalls. Plasma carotenoids were analyzed by HPLC using photodiode array detection. Fecal bacteria were analyzed by 16S rRNA DNA sequencing. Results presented are cross-sectional from the 36-week gestational study visit combined across both study arms due to lack of significant differences between intervention and usual care groups (n = 23 women with complete data). Recent intake of carotenoid-containing foods included carrots, sweet potatoes, mangos, apricots, and/or bell peppers for 48% of women; oranges/orange juice (17%); egg (39%); tomato/tomato-based sauces (52%); fruits (83%); and vegetables (65%). Average plasma carotenoid concentrations were 6.4 µg/dL α-carotene (AC), 17.7 µg/dL β-carotene (BC), 11.4 µg/dL cryptoxanthin, 39.0 µg/dL trans-lycopene, and 29.8 µg/dL zeaxanthin and lutein. AC and BC concentrations were higher in women who recently consumed foods high in carotenoids. CR concentrations were higher in women who consumed oranges/orange juice. Microbiota α-diversity positively correlated with AC and BC. Microbiota β-diversity differed significantly across reported intake of carotenoid containing foods and plasma concentrations of AC. This may reflect an effect of high fiber or improved overall dietary quality, rather than a specific effect of carotenoids. PRACTICAL APPLICATION: Little is known about the association between the gut microbiome and specific dietary microconstituents, such as carotenoids, especially during pregnancy. This research demonstrates that a carotenoid-rich diet during pregnancy supports a diverse microbiota, which could be one mechanism by which carotenoids promote health.

Cellular Adhesion Molecules in Young Adulthood and Cardiac Function in Later Life

BACKGROUND

E-selectin and intercellular adhesion molecule (ICAM)-1 are biomarkers of endothelial activation, which has been implicated in the pathogenesis of heart failure (HF) with preserved ejection fraction (HFpEF). However, the temporal associations between E-selectin and ICAM-1 with subclinical cardiac dysfunction are unclear.

OBJECTIVES

This study sought to assess the longitudinal associations of E-selectin and ICAM-1 with subclinical alterations in cardiac function.

METHODS

In the Coronary Artery Disease Risk Development in Young Adults study, a cohort of black and white young adults, we evaluated the associations of E-selectin and ICAM-1, obtained at year (Y) 7 (Y7) and Y15 examinations, with cardiac function assessed at Y30 after adjustment for key covariates.

RESULTS

Higher E-selectin (n = 1,810) and ICAM-1 (n = 1,548) at Y7 were associated with black race, smoking, hypertension, and higher body mass index. After multivariable adjustment, higher E-selectin at Y7 (β coefficient per 1 SD higher: 0.22; SE: 0.06; p < 0.001) and Y15 (β coefficient per 1 SD higher: 0.19; SE: 0.06; p = 0.002) was associated with worse left ventricular (LV) global longitudinal strain (GLS). Additionally, higher Y15 ICAM-1 (β coefficient per 1 SD higher: 0.18; SE: 0.06; p = 0.004) and its increase from Y7 to Y15 (β coefficient per 1 SD higher: 0.16; SE: 0.07; p = 0.03) were also independently associated with worse LV GLS. E-selectin and ICAM-1 partially mediated the associations between higher body mass index and black race with worse GLS. Neither E-selectin nor ICAM-1 was associated with measures of LV diastolic function after multivariable adjustment.

CONCLUSION

Circulating levels of E-selectin and ICAM-1 and increases in ICAM-1 over the course of young adulthood are associated with worse indices of LV systolic function in midlife. These findings suggest associations of endothelial activation with subclinical HF with preserved ejection fraction.

A longitudinal study of pre-pregnancy antioxidant levels and subsequent perinatal outcomes in black and white women: The CARDIA Study

BACKGROUND

Although protective associations between dietary antioxidants and pregnancy outcomes have been reported, randomized controlled trials of supplementation have been almost uniformly negative. A possible explanation is that supplementation during pregnancy may be too late to have a beneficial effect. Therefore, we examined the relationship between antioxidant levels prior to pregnancy and birth outcomes.

METHODS AND FINDINGS

Serum carotenoids and tocopherols were assayed in fasting specimens at 1985-86 (baseline) and 1992-1993 (year 7) from 1,215 participants in Coronary Artery Risk Development in Young Adults (CARDIA) study. An interviewer-administered quantitative food-frequency questionnaire assessed dietary intake of antioxidants. Pregnancy outcome was self-reported at exams every 2 to 5 years. Linear and logistic regression modeling was used to assess relationships of low birthweight (LBW; <2,500 g), continuous infant birthweight, preterm birth (PTB; <37 weeks) and length of gestation with antioxidant levels adjusted for confounders, as well as interactions with age and race.

RESULTS

In adjusted models, lycopene was associated with higher odds of LBW (adjusted odds ratio for top quartile, 2.15, 95% confidence interval 1.14, 3.92) and shorter gestational age (adjusted beta coefficient -0.50 weeks). Dietary intake of antioxidants was associated with lower birthweight, while supplement use of vitamin C was associated with higher gestational age (0.41 weeks, 0.01, 0.81).

CONCLUSIONS

Higher preconception antioxidant levels are not associated with better birth outcomes.

Collagen Biomarkers and Incidence of New Onset of Atrial Fibrillation in Subjects With No Overt Cardiovascular Disease at Baseline: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Atrial fibrosis is a hallmark of structural remodeling in atrial fibrillation (AF). Plasma procollagen type III N-terminal propeptide (PIIINP) reflects collagen synthesis and degradation while collagen type I carboxy-terminal telopeptide (ICTP) reflects collagen degradation. We aimed to study baseline plasma PIIINP and ICTP and their associations with incident AF in participants initially free of overt cardiovascular disease.

METHODS

In a stratified sample of the Multi-Ethnic Study of Atherosclerosis, initially aged 45-84 years, 3071 participants had both PIIINP and ICTP measured at baseline. Incident AF in 10-year follow-up was based on a hospital International Classification of Diseases code for AF or atrial flutter, in- or outpatient Medicare claims through 2011 (primarily in those aged 65-84 years), or ECG 10 years after baseline (n=357). The associations of PIIINP and ICTP with incident AF were estimated using Poisson regression with follow-up time offset.

RESULTS

Baseline PIIINP (5.50±1.55 µg/L) and ICTP (mean±SD, 3.41±1.37 µg/L) were positively related (both P<0.0001) to incident AF in a model adjusting for age, race/ethnicity, and sex, with an apparent threshold (relative incidence density 2.81 [1.94-4.08] for PIIINP ≥8.5 µg/L [3.5% of the sample] and 3.46 [2.36-5.07] for ICTP ≥7 µg/L [1.7% of the sample]). Findings were attenuated but remained statistically significant after further adjustment for systolic blood pressure, height, body mass index, smoking, and renal function. Additional adjustment for other risk factors and biomarkers of inflammation did not alter conclusions.

CONCLUSIONS

Plasma collagen biomarkers, particularly at elevated levels, were associated with excess risk for AF.

Summary data of serum concentrations of 32 persistent organic pollutants in young adults in relation to summary scores of persistent organic pollutants

This data article presents mean serum concentrations (wet weight and lipid standardized) of 32 persistent organic pollutants (POPs) detected in >75% of participants of the Coronary Artery Risk Development in Young Adults (CARDIA) study across levels of POPs scores, and their corresponding coefficients of determination. POPs scores were calculated as: A) the sum of each participant's log-transformed POPs concentrations (∑ of log Pops], or B) as the sum of the participants' log-transformed concentrations of each POP divided by the groups' standard deviation of the corresponding log-transformed POP (POPs summary score. Scores were calculated for both wet weight and lipid standardized concentrations and for all 32 POPs and for PCBs and organochlorine pesticides separately. POPs summary scores analyses were used in the article "Organochlorine pesticides and polychlorinated biphenyls (PCBs) in early adulthood and blood lipids over a 23-year follow-up" [Suarez-Lopez et al., 2018].

Organochlorine pesticides and polychlorinated biphenyls (PCBs) in early adulthood and blood lipids over a 23-year follow-up

BACKGROUND

Some evidence in humans suggests that persistent organic pollutants (POPs), including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), may alter the blood lipid composition. This study analyzed associations between serum POPs concentrations in young adulthood with blood lipid levels up to 23 years later.

METHODS

Serum POPs were measured in year 2 of follow-up (n = 180 men and women, ages: 20-32y), and plasma lipids in follow-up years 2, 7, 10, 15, 20 and 25. 32 POPs were detectable in ≥75% of participants (23 PCBs, 8 OCPs and PBB-153). We created summary scores for PCBs and OCPs for both wet-weight, and lipid standardized (LP) concentrations. We used repeated measures regression adjusting for demographic factors, BMI, smoking, diabetes status, among others.

RESULTS

We observed positive associations of the 23 LP-PCB score with total cholesterol (β_{per SD increase} [95%CI]: 5.0 mg/dL [0.7, 9.2]), triglycerides (7.8 mg/dL [-0.9, 16.5]), LDL (4.2 mg/dL [0.2, 8.2]), oxidized LDL 3.4 U/L (-0.05, 6.8), and cholesterol/HDL ratio (0.2 [0.02, 0.3]). The associations for triglycerides (14.7 mg/dL [0.4, 20.1]), cholesterol/HDL (0.33 [0.09, 0.56]) and, to some extent, LDL (4.7 md/dL [-1.6, 10.9]) were only observed among participants in the upper 50th percentile of BMI. Non-dioxin-like PCBs had stronger associations that dioxin-like PCBs. OCPs and PBB-s had positive associations with most outcomes.

CONCLUSIONS

PCBs and PBB-153 measured in young adulthood were positively associated with prospective alterations in most blood lipid components, with evidence of effect modification by BMI. Further longitudinal studies with multiple measures of POPs overtime are needed.

Circulating γ-Tocopherol Concentrations Are Inversely Associated with Antioxidant Exposures and Directly Associated with Systemic Oxidative Stress and Inflammation in Adults

Background

Although α- and γ-tocopherol are co-consumed antioxidants, circulating γ-tocopherol concentrations were paradoxically found to be inversely associated with total vitamin E intake and circulating α-tocopherol concentrations. There are limited data on this apparent paradox or on determinants of circulating γ-tocopherol concentrations.

Objective

To help clarify possible determinants of circulating γ-tocopherol concentrations, we investigated associations of circulating γ-tocopherol concentrations with various dietary and lifestyle factors and biomarkers of oxidative stress and inflammation.

Methods

We pooled cross-sectional data from 2 outpatient, adult, elective colonoscopy populations (pooled n = 419) on whom extensive dietary, lifestyle, and medical information was collected, and the following plasma concentrations were measured: α- and γ-tocopherol (via HPLC), F2-isoprostanes (FiPs; via gas chromatography-mass spectrometry), and high-sensitivity C-reactive protein (hsCRP; via latex-enhanced immunonephelometry). Multivariable general linear models were used to assess mean γ-tocopherol differences across quantiles of plasma antioxidant micronutrients, FiPs, and hsCRP; an oxidative balance score [OBS; a composite of anti- and pro-oxidant dietary and lifestyle exposures (a higher score indicates higher antioxidant relative to pro-oxidant exposures)]; and multiple dietary and lifestyle factors.

Results

Adjusted for serum total cholesterol, mean γ-tocopherol concentrations among those in the highest relative to the lowest tertiles of circulating α-tocopherol and β-carotene, the OBS, and total calcium and dietary fiber intakes were 31.0% (P < 0.0001), 29.0% (P < 0.0001), 27.6% (P = 0.0001), 29.7% (P < 0.0001), and 18.6% (P = 0.008) lower, respectively. For those in the highest relative to the lowest tertiles of circulating FiPs and hsCRP, mean γ-tocopherol concentrations were 50% (P < 0.0001) and 39.0% (P < 0.0001) higher, respectively.

Conclusions

These findings support the conclusion that circulating γ-tocopherol concentrations are inversely associated with antioxidant exposures and directly associated with systemic oxidative stress and inflammation in adults. Additional research on possible mechanisms underlying these findings and on whether circulating γ-tocopherol may serve as a biomarker of oxidative stress, inflammation, or both is needed.

Associations of Circulating 25-Hydroxyvitamin D3 Concentrations With Incident, Sporadic Colorectal Adenoma Risk According to Common Vitamin D-Binding Protein Isoforms

Concentration of 25-hydroxyvitamin D3 (25(OH)D3), the main circulating form of vitamin D, is inversely associated with incident, sporadic colorectal adenoma risk. We investigated whether this association differs by 2 functional variants in the vitamin D-binding protein (DBP) gene, group-specific component (GC), that encode for common protein isoforms Gc1s, Gc1f, and Gc2 linked to differences in vitamin D metabolism. We pooled data (418 patients with adenoma and 524 polyp-free control subjects) from 3 colonoscopy-based case-control studies (Minnesota, 1991-1994; North Carolina, 1994-1997; South Carolina, 2002). We estimated 25(OH)D3-adenoma associations, stratified by DBP isoforms, using multivariable logistic regression. Higher 25(OH)D3 concentrations were inversely associated with colorectal adenoma risk among those with the Gc2 isoform (per 10-ng/mL increase in 25(OH)D3, odds ratio = 0.71, 95% confidence interval: 0.56, 0.90), but not among those with only Gc1 isoforms (odds ratio = 1.07, 95% confidence interval: 0.87, 1.32; P for interaction = 0.03). Thus, the vitamin D-incident, sporadic colorectal adenoma association may differ by common DBP isoforms, and patients with the Gc2 isoform may particularly benefit from maintaining higher circulating 25(OH)D3 concentrations for adenoma prevention.

The Association of Serum Carotenoids, Tocopherols, and Ascorbic Acid With Rapid Kidney Function Decline: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

OBJECTIVE

Nutritional intervention targeting dietary intake modification is a major component of treatment for chronic kidney disease; however, little is known about the relationship between dietary intake and kidney function decline in individuals with preserved kidney function.

DESIGN AND METHODS

In this prospective cohort study we examined the association of biomarkers of dietary intake with kidney function decline over a 5-year interval in 2,152 men and women with cystatin-C-based estimated glomerular filtration rate > 60 mL/minute/1.73 m² from the Coronary Artery Risk Development in Young Adults study. The biomarkers of interest included carotenoids, tocopherols, and ascorbic acid. Multivariable logistic regression was used to explore the relationship between serum concentrations of the sum of 4 carotenoids (α-carotene, β-carotene, β-cryptoxanthin, and lutein/zeaxanthin), lycopene, α-tocopherol, γ-tocopherol, and ascorbic acid and rapid kidney function decline, defined as .15% decline in cystatin-C-based estimated glomerular filtration rate over 5 years.

RESULTS

During the 5-year follow-up, 290 participants (13.5%) experienced rapid kidney function decline. Relative to individuals in the lowest quartile of serum carotenoids, those in the highest quartile had significantly lower odds of rapid kidney function decline in the fully adjusted model (odds ratio, 0.51; 95% confidence interval [CI], 0.32-0.80; P trend, .02). No association of levels of serum tocopherols, ascorbic acid, or lycopene with kidney function decline was found. There was no evidence that results differed for individuals with hypertension or diabetes.

CONCLUSIONS

These results demonstrate that higher serum carotenoid levels, reflective of a fruit- and vegetable-rich dietary pattern, inversely associate with rapid kidney function decline in early middle adulthood and provide insight into how diet might play a role in chronic kidney disease prevention.

Collagen biomarkers and subclinical interstitial lung disease: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Lung fibrosis is attributed to derangements in extracellular matrix remodeling, a process driven by collagen turnover. We examined the association of two collagen biomarkers, carboxy-terminal telopeptide of collagen type I (ICTP) and amino-terminal propeptide of type III procollagen (PIIINP), with subclinical interstitial lung disease (ILD) in adults.

METHODS

We performed a cross-sectional analysis of 3244 participants age 45-84 years in the Multi-Ethnic Study of Atherosclerosis. Serum ICTP and PIIINP levels were measured at baseline by radioimmunoassay. Subclinical ILD was defined as high attenuation areas (HAA) in the lung fields on baseline cardiac CT scans. Interstitial lung abnormalities (ILA) were measured in 1082 full-lung CT scans at 9.5 years median follow-up. We used generalized linear models to examine the associations of collagen biomarkers with HAA and ILA.

RESULTS

Median (IQR) for ICTP was 3.2 μg/L (2.6-3.9 μg/L) and for PIIINP was 5.3 μg/L (4.5-6.2 μg/L). In fully adjusted models, each SD increment in ICTP was associated with a 1.3% increment in HAA (95% CI 0.2-2.4%, p = 0.02) and each SD increment in PIIINP was associated with a 0.96% increment in HAA (95% CI 0.06-1.9%, p = 0.04). There was no association between ICTP or PIIINP and ILA. There was no evidence of effect modification by gender, race, smoking status or eGFR.

CONCLUSIONS

Higher levels of collagen biomarkers are associated with greater HAA independent of gender, race and smoking status. This suggests that extracellular matrix remodeling may accompany subclinical ILD prior to the onset of clinically evident disease.

Genome-wide association study of homocysteine in African Americans from the Jackson Heart Study, the Multi-Ethnic Study of Atherosclerosis, and the Coronary Artery Risk in Young Adults study

Homocysteine (Hcy) is a heritable biomarker for CVD, peripheral artery disease, stroke, and dementia. Little is known about genetic associations with Hcy in individuals of African ancestry. We performed a genome-wide association study for Hcy in 4927 AAs from the Jackson Heart Study (JHS), the Multi-Ethnic Study of Atherosclerosis (MESA), and the Coronary Artery Risk in Young Adults (CARDIA) study. Analyses were stratified by sex and results were meta-analyzed within and across sex. In the sex-combined meta-analysis, we observed genome-wide significant evidence (p < 5.0 × 10-8) for the NOX4 locus (lead variant rs2289125, β = -0.15, p = 5.3 × 1011). While the NOX4 locus was previously reported as associated with Hcy in European-American populations, rs2289125 remained genome-wide significant when conditioned on the previously reported lead variants. Previously reported genome-wide significant associations at NOX4, MTR, CBS, and MMACHC were also nominally (p < 0.050) replicated in AAs. Associations at the CPS1 locus, previously reported in females only, also was replicated specifically in females in this analysis, supporting sex-specific effects for this locus. These results suggest that there may be a combination of cross-population and population-specific genetic effects, as well as differences in genetic effects between males and females, in the regulation of Hcy levels.

Predictive Value of Collagen Biomarkers for Heart Failure With and Without Preserved Ejection Fraction: MESA (Multi-Ethnic Study of Atherosclerosis)

BACKGROUND

Collagen biomarkers may correlate with incident heart failure (HF) and its subtypes. We hypothesized that circulating procollagen type III N-terminal propeptide (PIIINP) and collagen type I carboxy-terminal telopeptide (ICTP) predict incident HF.

METHODS AND RESULTS

We used a stratified sampling design in a multiethnic sample of 3187 subjects, initially aged 45 to 84 years and free of cardiovascular disease. We assayed baseline serum PIIINP and ICTP concentrations using radioimmunoassay. Incident HF was adjudicated, distinguishing reduced ejection fraction (HFrEF; EF <45%) from preserved EF (HFpEF; EF ≥45%). The incidence density for HFpEF and HFrEF was computed using Poisson regression per SD for each of PIIINP and ICTP, adjusting in model 1 for age, race, sex, and renal function or in model 2 for these variables plus blood pressure and medication. Mean (SD) ICTP was 3.38±1.77 μg/L, and mean (SD) PIIINP was 5.48±2.04 μg/L. Among the HF cases, 96 were HFrEF and 107 were HFpEF. Neither ICTP nor PIIINP significantly predicted incident HFrEF. The incidence density for HFpEF per 100 people observed for 13 years was 1.65 for low PIIINP (lower 6 octiles) versus 3.00 for higher PIIINP (P=0.002) in model 1 and correspondingly 1.45 versus 2.59 (P=0.003) in model 2. For low ICTP (lower 7 octiles) versus higher ICTP (octile 8), incidence densities were 1.79 versus 3.64 (P=0.002) in model 1 and 1.58 versus 3.12 (P=0.002) in model 2.

CONCLUSIONS

High levels of circulating ICTP and PIIINP as collagen biomarkers appear to be associated with incident HFpEF, but not HFrEF.

Transethnic insight into the genetics of glycaemic traits: fine-mapping results from the Population Architecture using Genomics and Epidemiology (PAGE) consortium

AIMS/HYPOTHESIS

Elevated levels of fasting glucose and fasting insulin in non-diabetic individuals are markers of dysregulation of glucose metabolism and are strong risk factors for type 2 diabetes. Genome-wide association studies have discovered over 50 SNPs associated with these traits. Most of these loci were discovered in European populations and have not been tested in a well-powered multi-ethnic study. We hypothesised that a large, ancestrally diverse, fine-mapping genetic study of glycaemic traits would identify novel and population-specific associations that were previously undetectable by European-centric studies.

METHODS

A multiethnic study of up to 26,760 unrelated individuals without diabetes, of predominantly Hispanic/Latino and African ancestries, were genotyped using the Metabochip. Transethnic meta-analysis of racial/ethnic-specific linear regression analyses were performed for fasting glucose and fasting insulin. We attempted to replicate 39 fasting glucose and 17 fasting insulin loci. Genetic fine-mapping was performed through sequential conditional analyses in 15 regions that included both the initially reported SNP association(s) and denser coverage of SNP markers. In addition, Metabochip-wide analyses were performed to discover novel fasting glucose and fasting insulin loci. The most significant SNP associations were further examined using bioinformatic functional annotation.

RESULTS

Previously reported SNP associations were significantly replicated (p ≤ 0.05) in 31/39 fasting glucose loci and 14/17 fasting insulin loci. Eleven glycaemic trait loci were refined to a smaller list of potentially causal variants through transethnic meta-analysis. Stepwise conditional analysis identified two loci with independent secondary signals (G6PC2-rs477224 and GCK-rs2908290), which had not previously been reported. Population-specific conditional analyses identified an independent signal in G6PC2 tagged by the rare variant rs77719485 in African ancestry. Further Metabochip-wide analysis uncovered one novel fasting insulin locus at SLC17A2-rs75862513.

CONCLUSIONS/INTERPRETATION

These findings suggest that while glycaemic trait loci often have generalisable effects across the studied populations, transethnic genetic studies help to prioritise likely functional SNPs, identify novel associations that may be population-specific and in turn have the potential to influence screening efforts or therapeutic discoveries.

DATA AVAILABILITY

The summary statistics from each of the ancestry-specific and transethnic (combined ancestry) results can be found under the PAGE study on dbGaP here: https://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?study_id=phs000356.v1.p1.

Correction to: Transethnic insight into the genetics of glycaemic traits: fine-mapping results from the Population Architecture using Genomics and Epidemiology (PAGE) consortium

The authors regret that Yinchang Lu's name incorrectly included a middle initial in the author list. The details given in this erratum are correct.

Dietary Weight Loss, Exercise, and Oxidative Stress in Postmenopausal Women: A Randomized Controlled Trial

Oxidative stress, a potential mechanism linking obesity and cancer, results from an imbalance between activation/inactivation of reactive oxygen species, byproducts of cellular metabolism. In a randomized controlled trial, we investigated effects of diet and/or exercise on biomarkers of oxidative stress. A total of 439 overweight/obese [body mass index (BMI) > 25 kg/m²] postmenopausal women, ages 50 of 75 years, were randomized to 12 months of (i) reduced-calorie weight loss diet ("diet"; n = 118); (ii) moderate-to-vigorous intensity aerobic exercise ("exercise"; n = 117); (iii) combined diet and exercise intervention ("diet + exercise"; n = 117); or (iv) control (n = 87). Outcomes were circulating markers of oxidative stress, including fluorescent oxidation products (FOP), F₂-isoprostanes, and oxidized low-density lipoprotein (LDL). On average, participants were 57.9 years, with a BMI of 30.9 kg/m² F₂-isprostanes were significantly reduced in the diet (-22.7%, P = 0.0002) and diet + exercise (-23.5%, P < 0.0001) arms versus controls (-2.99%) and nonsignificantly reduced in the exercise arm (-14.5%, P = 0.01). Participants randomized to the diet and diet + exercise arms had significant increases in levels of FOP [control -5.81%; diet +14.77% (P = 0.0001); diet + exercise +17.45%, (P = 0.0001)]. In secondary analyses, increasing weight loss was statistically significantly associated with linear trends of greater reductions in oxidized LDL and in F₂-isoprostanes and increases in FOP. Compared with controls, exercise participants whose maximal oxygen consumption increased had significant decreases in levels of F₂-isoprostanes and in oxidized LDL and increases in FOP. Dietary weight loss, with or without exercise, significantly reduced some markers of oxidative stress in postmenopausal women. Cancer Prev Res; 9(11); 835-43. ©2016 AACR.

Impact of common genetic determinants of Hemoglobin A1c on type 2 diabetes risk and diagnosis in ancestrally diverse populations: A transethnic genome-wide meta-analysis

BACKGROUND

Glycated hemoglobin (HbA1c) is used to diagnose type 2 diabetes (T2D) and assess glycemic control in patients with diabetes. Previous genome-wide association studies (GWAS) have identified 18 HbA1c-associated genetic variants. These variants proved to be classifiable by their likely biological action as erythrocytic (also associated with erythrocyte traits) or glycemic (associated with other glucose-related traits). In this study, we tested the hypotheses that, in a very large scale GWAS, we would identify more genetic variants associated with HbA1c and that HbA1c variants implicated in erythrocytic biology would affect the diagnostic accuracy of HbA1c. We therefore expanded the number of HbA1c-associated loci and tested the effect of genetic risk-scores comprised of erythrocytic or glycemic variants on incident diabetes prediction and on prevalent diabetes screening performance. Throughout this multiancestry study, we kept a focus on interancestry differences in HbA1c genetics performance that might influence race-ancestry differences in health outcomes.

METHODS & FINDINGS

Using genome-wide association meta-analyses in up to 159,940 individuals from 82 cohorts of European, African, East Asian, and South Asian ancestry, we identified 60 common genetic variants associated with HbA1c. We classified variants as implicated in glycemic, erythrocytic, or unclassified biology and tested whether additive genetic scores of erythrocytic variants (GS-E) or glycemic variants (GS-G) were associated with higher T2D incidence in multiethnic longitudinal cohorts (N = 33,241). Nineteen glycemic and 22 erythrocytic variants were associated with HbA1c at genome-wide significance. GS-G was associated with higher T2D risk (incidence OR = 1.05, 95% CI 1.04-1.06, per HbA1c-raising allele, p = 3 × 10-29); whereas GS-E was not (OR = 1.00, 95% CI 0.99-1.01, p = 0.60). In Europeans and Asians, erythrocytic variants in aggregate had only modest effects on the diagnostic accuracy of HbA1c. Yet, in African Americans, the X-linked G6PD G202A variant (T-allele frequency 11%) was associated with an absolute decrease in HbA1c of 0.81%-units (95% CI 0.66-0.96) per allele in hemizygous men, and 0.68%-units (95% CI 0.38-0.97) in homozygous women. The G6PD variant may cause approximately 2% (N = 0.65 million, 95% CI 0.55-0.74) of African American adults with T2D to remain undiagnosed when screened with HbA1c. Limitations include the smaller sample sizes for non-European ancestries and the inability to classify approximately one-third of the variants. Further studies in large multiethnic cohorts with HbA1c, glycemic, and erythrocytic traits are required to better determine the biological action of the unclassified variants.

CONCLUSIONS

As G6PD deficiency can be clinically silent until illness strikes, we recommend investigation of the possible benefits of screening for the G6PD genotype along with using HbA1c to diagnose T2D in populations of African ancestry or groups where G6PD deficiency is common. Screening with direct glucose measurements, or genetically-informed HbA1c diagnostic thresholds in people with G6PD deficiency, may be required to avoid missed or delayed diagnoses.

Circulating Cellular Adhesion Molecules and Cognitive Function: The Coronary Artery Risk Development in Young Adults Study

OBJECTIVE

Higher circulating concentrations of cellular adhesion molecules (CAMs) can be used as markers of endothelial dysfunction. Given that the brain is highly vascularized, we assessed whether endothelial function is associated with cognitive performance.

METHOD

Within the Coronary Artery Risk Development in Young Adults (CARDIA) Study, excluding N = 54 with stroke before year 25, we studied CAMs among N = 2,690 black and white men and women in CARDIA year 7 (1992-1993, ages 25-37) and N = 2,848 in CARDIA year 15 (2000-2001, ages 33-45). We included subjects with levels of circulating soluble CAMs measured in year 7 or 15 and cognitive function testing in year 25 (2010-2011, ages 43-55). Using multiple regression analysis, we evaluated the association between CAMs and year 25 cognitive test scores: Rey Auditory Verbal Learning Test (RAVLT, memory), Digit Symbol Substitution Test (DSST, speed of processing), and the Stroop Test (executive function).

RESULT

All CAM concentrations were greater in year 15 vs. year 7. Adjusting for age, race, sex, education, smoking, alcohol, diet, physical activity, participants in the fourth vs. the first quartile of CARDIA year 7 of circulating intercellular adhesion molecule-1 (ICAM-1) scored worse on RAVLT, DSST, and Stroop Test (p ≤ 0.05) in CARDIA year 25. Other CAMs showed little association with cognitive test scores. Findings were similar for ICAM-1 assessed at year 15. Adjustment for possibly mediating physical factors attenuated the findings.

CONCLUSION

Higher circulating ICAM-1 at average ages 32 and 40 was associated with lower cognitive skills at average age 50. The study is consistent with the hypothesis that endothelial dysfunction is associated with worse short-term memory, speed of processing, and executive function.

Collagen Turnover Markers in Relation to Future Cardiovascular and Noncardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Sustained remodeling of extracellular matrix can compromise organs and tissues. Procollagen type III N-terminal propeptide (PIIINP) and collagen type I carboxy-terminal telopeptide (ICTP) reflect collagen synthesis and degradation. We studied their predictive value for future death and disease.

METHODS

A total of 3068 men and women in the Multi-Ethnic Study of Atherosclerosis who were free of cardiovascular disease (CVD) and in generally good health had a baseline blood sample taken for ICTP and PIIINP. Median follow-up was 13.0 years. Among 4 primary outcomes, CVD events (n = 697) were adjudicated, death (n = 571) was by death certificate, and chronic inflammatory-related severe hospitalization and death (ChrIRD, n = 726) and total cancer (n = 327) were classified using International Classification of Diseases codes. We used Poisson regression to study baseline ICTP and PIIINP relative to these outcomes.

RESULTS

Mean (SD) PIIINP was 5.47 (1.95) μg/L and ICTP was 3.37 (1.70) μg/L. PIIINP and ICTP were highly correlated with each other and with estimated glomerular filtration rate (eGFR). Adjustment for age and eGFR attenuated relative risks, remaining 20%-30% per SD of both PIIINP and ICTP in prediction for total death and ChrIRD, and of PIIINP for cancer, with little additional attenuation by adjusting for risk factors and inflammatory biomarkers. CVD outcome was generally unrelated to PIIINP but became marginally inversely related to ICTP in the most adjusted model.

CONCLUSIONS

The collagen biomarkers PIIINP and ICTP, in part through pathophysiologically parallel associations with renal function, predicted ChrIRD and total death. Moreover, PIIINP predicted future cancer. These collagen markers may help differentiate healthy from unhealthy aging.

Smoking habits and parathyroid hormone concentrations in young adults: The CARDIA study

Conflicting results have been reported concerning a relationship between smoking and serum PTH. Our study objective was to examine whether smoking was associated with serum PTH independent of correlates of PTH among young adults, and explore potential mechanisms. This was a cross-sectional study of healthy individuals, 24-36 years old, examined during 1992 through 1993 in California, USA (a subset of Coronary Artery Risk Development in Young Adults study). Linear regression was used to obtain adjusted means of PTH according to smoking habit (current, former, never). Biomarkers for calcium metabolism and bone turnover (including serum concentrations of osteocalcin, bone-specific alkaline phosphatase, and 24-hour urinary excretion of calcium) and bone mineral density were similarly compared by smoking. 376 participants were analyzed (171 women, 181 black). Over half reported never smoking. We observed lower PTH in current smokers compared to non-smokers and found no evidence of an interaction by race and sex. PTH was lowest in current smokers, intermediate in former smokers, and highest in never smokers (geometric mean PTH: 23.6, 26.7, 27.4 pg/mL, respectively: P for trend, 0.006) after adjusting for potential confounders including calcium intake. Among the biomarkers, serum osteocalcin concentration and 24-hour urinary excretion of calcium were lowest in current smokers. We observed no smoking-related difference in bone mineral density. In this community-based sample of young adult men and women, smoking was associated with significantly lower PTH concentration. The mechanism and clinical implication of the finding, however, remains uncertain.

Microbiota-Dependent Metabolite Trimethylamine N-Oxide and Coronary Artery Calcium in the Coronary Artery Risk Development in Young Adults Study (CARDIA)

Background

Clinical studies implicate trimethylamine N‐oxide (TMAO; a gut microbiota‐dependent nutrient metabolite) in cardiovascular disease risk. There is a lack of population‐based data on the role of TMAO in advancing early atherosclerotic disease. We tested the prospective associations between TMAO and coronary artery calcium (CAC) and carotid intima‐media thickness (cIMT).

Methods and Results

Data were from the Coronary Artery Risk Development in Young Adults Study (CARDIA), a biracial cohort of US adults recruited in 1985–1986 (n=5115). We randomly sampled 817 participants (aged 33–55 years) who attended examinations in 2000–2001, 2005–2006, and 2010–2011, at which CAC was measured by computed tomography and cIMT (2005–2006) by ultrasound. TMAO was quantified using liquid chromotography mass spectrometry on plasma collected in 2000–2001. Outcomes were incident CAC, defined as Agatston units=0 in 2000–2001 and >0 over 10‐year follow‐up, CAC progression (any increase over 10‐year follow‐up), and continuous cIMT. Over the study period, 25% (n=184) of those free of CAC in 2000–2001 (n=746) developed detectable CAC. In 2000–2001, median (interquartile range) TMAO was 2.6 (1.8–4.2) μmol/L. In multivariable‐adjusted models, TMAO was not associated with 10‐year CAC incidence (rate ratio=1.03; 95% CI: 0.71–1.52) or CAC progression (0.97; 0.68–1.38) in Poisson regression, or cIMT (beta coefficient: −0.009; −0.03 to 0.01) in linear regression, comparing the fourth to the first quartiles of TMAO.

Conclusions

In this population‐based study, TMAO was not associated with measures of atherosclerosis: CAC incidence, CAC progression, or cIMT. These data indicate that TMAO may not contribute significantly to advancing early atherosclerotic disease risk among healthy early‐middle‐aged adults.

A community-based lifestyle and weight loss intervention promoting a Mediterranean-style diet pattern evaluated in the stroke belt of North Carolina: the Heart Healthy Lenoir Project

BACKGROUND

Because residents of the southeastern United States experience disproportionally high rates of cardiovascular disease (CVD), it is important to develop effective lifestyle interventions for this population.

METHODS

The primary objective was to develop and evaluate a dietary, physical activity (PA) and weight loss intervention for residents of the southeastern US. The intervention, given in eastern North Carolina, was evaluated in a 2 year prospective cohort study with an embedded randomized controlled trial (RCT) of a weight loss maintenance intervention. The intervention included: Phase I (months 1-6), individually-tailored intervention promoting a Mediterranean-style dietary pattern and increased walking; Phase II (months 7-12), option of a 16-week weight loss intervention for those with BMI ≥ 25 kg/m(2) offered in 2 formats (16 weekly group sessions or 5 group sessions and 10 phone calls) or a lifestyle maintenance intervention; and Phase III (months 13-24), weight loss maintenance RCT for those losing ≥ 8 lb with all other participants receiving a lifestyle maintenance intervention. Change in diet and PA behaviors, CVD risk factors, and weight were assessed at 6, 12, and 24 month follow-up.

RESULTS

Baseline characteristics (N = 339) were: 260 (77 %) females, 219 (65 %) African Americans, mean age 56 years, and mean body mass index 36 kg/m(2). In Phase I, among 251 (74 %) that returned for 6 month follow-up, there were substantial improvements in diet score (4.3 units [95 % CI 3.7 to 5.0]), walking (64 min/week [19 to 109]), and systolic blood pressure (-6.4 mmHg [-8.7 to -4.1]) that were generally maintained through 24 month follow-up. In Phase II, 138 (57 group only, 81 group/phone) chose the weight loss intervention and at 12 months, weight change was: -3.1 kg (-4.9 to -1.3) for group (N = 50) and -2.1 kg (-3.2 to -1.0) for group/phone combination (N = 75). In Phase III, 27 participants took part in the RCT. At 24 months, weight loss was -2.1 kg (-4.3 to 0.0) for group (N = 51) and -1.1 kg (-2.7 to 0.4) for combination (N = 72). Outcomes for African American and whites were similar.

CONCLUSIONS

The intervention yielded substantial improvement in diet, PA, and blood pressure, but weight loss was modest.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01433484.

Abstract 4292: Mitochodrial D-loop polymorphisms are associated with colorectal adenoma risk

Somatic mutational events in the mitochondria have been detected in adenomatous polyps. However, the contribution of germline variation in the mitochondrial DNA towards risk of colorectal adenomas, well recognized precursor lesions to colorectal cancer, has not been evaluated previously. Hence, we evaluated associations of mitochondrial polymorphisms in the D-loop and non-D loop regions with incident colorectal adenoma in three pooled colonoscopy-based case-control studies (n = 327 colorectal adenoma cases and 420 controls) that used identical methods for case ascertainment and risk factor determination. We sequenced a 1,124 bp fragment to comprehensively identify all genetic variation in the mitochondrial D-loop region, and used the Sequenom platform to genotype 64 previously described tagSNPs in the non-D loop region. We used multivariate unconditional logistic regression to analyze the association between the mitochondrial polymorphisms and colorectal adenoma risk after adjustment for potential confounders. We identified 320 germline mutations in the D-loop region; 30 (9%) had a minor allele frequency (MAF) ≥ 5%. Most of the mutations clustered in the hypervariable regions HV1 (n = 124; 39%) and HV2 (n = 111; 35%) of the D-loop region. Among the nine common polymorphisms (MAF ≥ 5%) in the HV1 region, four polymorphisms (mt16069, mt16278, mt16294, and mt16296) were statistically significantly directly associated with colorectal adenoma risk (odds ratios [OR]: 1.76 - 2.66; p-values: 0.001 - 0.04). In addition, the polyC tract in the HV1 region was inversely associated with colorectal adenoma risk (OR: 0.90; p = 0.03). None of the other polymorphisms in the mitochondrial D-loop region tract was associated with colorectal adenoma risk. After correction for multiple comparisons, none of the mitochondrial tagSNPs in the non-D loop region was associated with colorectal adenoma risk. These findings suggest that polymorphisms in the HV1 region of the mitochondrial D-loop may be associated with colorectal adenoma risk and support further investigation in future studies.

Citation Format: Bharat Thyagarajan, Weihua Guan, Veronika Fedirko, Helene Barcelo, Myron D. Gross, Michael Goodman, Roberd M. Bostick. Mitochodrial D-loop polymorphisms are associated with colorectal adenoma risk. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4292.

Abstract 4281: Mitochondrial DNA copy number, urinary isoprostanes and colorectal cancer risk

Previous epidemiological studies on mitochondrial DNA (mtDNA) copy number and risk of colorectal cancer have yielded mixed results. One study reported a positive association, another reported an inverse association, and a third, a U-shaped association of mtDNA copy number with colorectal cancer risk. Since oxidative stress is one of the proposed underlying mechanisms that may link mtDNA copy number variation to colorectal cancer risk, we conducted a matched case-control study of incident colorectal cancer nested within the Singapore Chinese Health Study. Pre-diagnostic blood and urine samples were obtained from 448 colorectal cancer cases and 869 age- and sex-matched controls. The mtDNA copy number in peripheral white cells was measured using real time PCR and urinary F2-isoprostanes were quantified using a liquid chromatography mass spectrometry based method. Conditional logistic regression was used to estimate associations of mtDNA copy number and urinary F2-isoprostanes with incident colorectal cancer. The odds ratios (OR) and 95% confidence intervals (95% CI) for those in the highest relative to those in the lowest quartiles of relative mtDNA copy numbers and urinary F2-isoprostanes were 1.02 (95% CI 0.72 - 1.43; p for trend = 0.56) and 1.11 (95% CI 0.78-1.59; p for trend = 0.35) respectively. Urinary F2-isoprostanes levels were not associated with the mtDNA copy number among the controls (r = 0.03; p = 0.33). The results of this prospective study suggest that white blood cell mtDNA copy number or urinary levels of F2-isoprostanes in biospecimens collected several years prior to the diagnosis of colorectal cancer may not be associated with risk of developing colorectal cancer.

Citation Format: Bharat Thyagarajan, Renwei Wang, Woon-Puay Koh, Helene Barcelo, Jennifer Adams-Haduch, Weihua Guan, Roberd M. Bostick, Jian-Min Yuan, Myron D. Gross. Mitochondrial DNA copy number, urinary isoprostanes and colorectal cancer risk. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4281.

Do glycemic marker levels vary by race? Differing results from a cross-sectional analysis of individuals with and without diagnosed diabetes

OBJECTIVE

It is well known that A1c varies by race. However, racial differences in other biomarkers of hyperglycemia are less well characterized. The objective of this study was to determine whether average levels of glycemic markers differ by race in adults with and without diagnosed diabetes, before and after accounting for postchallenge glucose.

RESEARCH DESIGN AND METHODS

This cross-sectional study included 2692 middle-aged men and women (5.5% with diagnosed diabetes; 44% African-American; and 56% white) from the Coronary Artery Risk Development in Young Adults Study (2005-2006) who had fasting glucose, 2-hour postchallenge glucose, A1c, glycated albumin, fructosamine, and 1,5-anhydroglucitol (1,5-AG) measured. Multiple linear regression was used to evaluate racial differences in mean levels of each glycemic marker stratified by the diabetes status and adjusted for sociodemographics, cardiovascular factors, and postchallenge glucose.

RESULTS

Among those with diagnosed diabetes, racial differences were not observed for any of the glycemic markers. In contrast, among those without diagnosed diabetes, African-Americans had higher mean levels than whites of A1c (β=0.19% points; 95% CI 0.14 to 0.24), glycated albumin (β=0.82% points; 95% CI 0.68 to 0.97), fructosamine (β=8.68 μmol/L; 95% CI 6.68 to 10.68), and 2-hour glucose (β=3.50 mg/dL; 95% CI 0.10 to 6.90) after multivariable adjustment, whereas there were no statistically significant racial difference in 1,5-AG. The racial differences observed for A1c, glycated albumin, and fructosamine persisted after further adjustment for fasting and 2-hour glucose and were of similar magnitude (SD units).

CONCLUSIONS

Racial differences in glycemic marker levels were evident among middle-aged adults without diagnosed diabetes even after adjustment for postchallenge glucose. Whether these racial differences in biomarkers of hyperglycemia affect the risk of complications warrants additional study.

Longitudinal associations between adiponectin and cardiac structure differ by hypertensive status: Coronary Artery Risk Development in Young Adults

OBJECTIVE

We studied the longitudinal association between adiponectin and cardiac structure and function 10 years later stratified by hypertension status.

METHODS

Multicenter longitudinal study of black and white men and women that began in 1985-1986, when participants were 18-30 years old. Adiponectin was measured at year 15(2000-2001). Echocardiograms were completed at year 25(2010-2011). Participants were stratified by the presence of hypertension. Risk factor-adjusted echocardiographic variables were compared across adiponectin quintiles. Linear and quadratic regression models were also derived for risk factor-adjusted echocardiographic variables.

RESULTS

Relative to the lowest quintile of adiponectin, participants from the highest quintile had a 6% lower LV mass index (LVMi) among normotensives, and an 8% higher LVMi among hypertensives. Among normotensive participants, regression analysis demonstrated a linear inverse relationship between adiponectin and LV mass, LVMi, posterior wall thickness (PWT) and ventricular septal thickness (VST) (all p≤0.05). Among hypertensive participants, regression analysis demonstrated a U-shaped relationship between adiponectin and LV mass, LVMi, PWT and VST (p≤0.005 for all quadratic terms).

CONCLUSIONS

Among normotensive participants, higher adiponectin may be a useful marker of less adverse future cardiac structure. Further study is required to see if adiponectin receptor agonists may provide a benefit among these individuals. Among hypertensive participants, further study is required to assess the prognostic and therapeutic use of adiponectin.

Oxidative stress, inflammation, endothelial dysfunction and incidence of type 2 diabetes

BACKGROUND

Oxidative stress, inflammation and endothelial dysfunction are interrelated factors in the etiology of cardiovascular disease, but their linkage to type 2 diabetes is less clear. We examined the association of these biomarkers with incident type 2 diabetes (T2D).

METHODS

Analysis of 2339 participants in the community-based coronary artery risk development in young adults (CARDIA) study. Participants (age 40.1 ± 3.6 years, 44 % Black, 58 % women) were free of diabetes, and were followed 10 years. Cox regression was used to estimate hazard ratios (HRs) for incident T2D adjusting for the other biomarkers under study, demographic and lifestyle measures, dietary biomarkers, BMI (kg/m(2)) and metabolic syndrome components.

RESULTS

F2-isoprostanes and oxidized LDL (oxidative stress) were positively associated with incident T2D, but the associations were attenuated by adjustment for BMI. C-reactive protein was positively associated with T2D even with full adjustment: HR (95 % CI) = 2.21 (1.26-3.88) for quartile 4 (Q4) v. quartile 1 (Q1). The HR (95 % CI) for T2D for biomarkers of endothelial dysfunction ICAM-1 and E-selectin for Q4 v. Q1 were 1.64 (0.96-2.81) and 1.68 (1.04-2.71) respectively, with full adjustment. Including these two markers in a common risk score incorporating BMI and clinical measures improved the prediction probability of T2D: relative risk for the average person classified up compared to the average person classified down: 1.09, (1.06-1.13), P < 0.0001.

CONCLUSIONS

Biomarkers of inflammation and endothelial dysfunction were positively associated with incident T2D. ICAM-1 and E-selectin add to the prediction of T2D beyond a common risk score.

Oxidative stress, anti-oxidants and the cross-sectional and longitudinal association with depressive symptoms: results from the CARDIA study

Depression may be accompanied by increased oxidative stress and decreased circulating anti-oxidants. This study examines the association between depressive symptoms, F2-isoprostanes and carotenoids in a US community sample. The study includes 3009 participants (mean age 40.3, 54.2% female) from CARDIA (Coronary Artery Risk Development in Young Adults). Cross-sectional analyses were performed on data from the year 15 examination (2000-2001) including subjects whose depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale (CES-D) and had measurements of plasma F2-isoprostanes (gas chromatography/mass spectrometry) or serum carotenoids (high-performance liquid chromatography). Carotenoids zeaxanthin/lutein, β-cryptoxanthin, lycopene, α-carotene, β-carotene were standardized and summed. Longitudinal analyses were conducted using the data from other examinations at 5-year intervals. Cross-lagged analyses investigated whether CES-D predicted F2-isoprostanes or carotenoids at the following exam, and vice versa. Regression analyses were controlled for sociodemographics, health and lifestyle factors. F2-isoprostanes were higher in subjects with depressive symptoms (CES-D ⩾ 16) after adjustment for sociodemographics (55.7 vs 52.0 pg ml(-1); Cohen's d = 0.14, P < 0.001). There was no difference in F2-isoprostanes after further adjustment for health and lifestyle factors. Carotenoids were lower in those with CES-D scores ⩾ 16, even after adjustment for health and lifestyle factors (standardized sum 238.7 vs 244.0, Cohen's d = -0.16, P < 0.001). Longitudinal analyses confirmed that depression predicts subsequent F2-isoprostane and carotenoid levels. Neither F2-isoprostanes nor carotenoids predicted subsequent depression. In conclusion, depressive symptoms were cross-sectionally and longitudinally associated with increased F2-isoprostanes and decreased carotenoids. The association with F2-isoprostanes can largely be explained by lifestyle factors, but lower carotenoids were independently associated with depressive symptoms.

Serum 25-hydroxyvitamin D and the incidence of atrial fibrillation: the Atherosclerosis Risk in Communities (ARIC) study

AIMS

To assess the prospective association between circulating 25-hydroxyvitamin D [25(OH)D] and atrial fibrillation (AF) risk.

METHODS AND RESULTS

We studied 12 303 participants from the Atherosclerosis Risk in Communities study without baseline AF (1990-92). Baseline serum total 25(OH)D was measured using mass spectrometry. Incident AF cases were identified from electrocardiograms, hospital discharge codes, and death certificates through 2012. We estimated hazard ratios (HRs) and 95% confidence intervals (95% CIs) of AF across clinical categories of serum 25(OH)D concentrations with multivariable Cox models, and tested interactions by age, race, and sex. We meta-analysed our results with those from published prospective studies that reported associations between 25(OH)D and AF risk. During a median follow-up of 21 years, we identified 1866 AF events. In multivariable models, deficient 25(OH)D status (<20 ng/mL), compared with optimal levels (≥30 ng/mL), was not associated with AF risk (HR, 95% CI: 1.10, 0.96-1.26). A significant interaction of 25(OH)D concentrations with age (P = 0.01), but not with race or sex (P > 0.40), was identified, with higher risk of AF among those with deficient 25(OH)D status in younger (HR, 95% CI: 1.35, 1.05-1.73) but not older individuals (HR, 95% CI: 1.02, 0.86-1.21). A meta-analysis of these results and four prospective studies did not support a clinically relevant association of circulating 25(OH)D with AF risk [pooled HR, 95%CI: 1.04, 1.00-1.08, per 1 SD lower 25(OH)D].

CONCLUSION

Low serum 25(OH)D was not associated with incident AF in a community-based cohort and in a meta-analysis of prospective studies. A possible association in younger individuals warrants further investigation.

Plasma Ascorbic Acid, A Priori Diet Quality Score, and Incident Hypertension: A Prospective Cohort Study

Vitamin C may reduce risk of hypertension, either in itself or by marking a healthy diet pattern. We assessed whether plasma ascorbic acid and the a priori diet quality score relate to incident hypertension and whether they explain each other's predictive abilities. Data were from 2884 black and white adults (43% black, mean age 35 years) initially hypertension-free in the Coronary Artery Risk Development in Young Adults Study (study year 10, 1995-1996). Plasma ascorbic acid was assessed at year 10 and the diet quality score at year 7. Eight-hundred-and-forty cases of hypertension were documented between years 10 and 25. After multiple adjustments, each 12-point (1 SD) higher diet quality score at year 7 related to mean 3.7 μmol/L (95% CI 2.9 to 4.6) higher plasma ascorbic acid at year 10. In separate multiple-adjusted Cox regression models, the hazard ratio of hypertension per 19.6-μmol/L (1 SD) higher ascorbic acid was 0.85 (95% CI 0.79-0.92) and per 12-points higher diet score 0.86 (95% CI 0.79-0.94). These hazard ratios changed little with mutual adjustment of ascorbic acid and diet quality score for each other, or when adjusted for anthropometric variables, diabetes, and systolic blood pressure at year 10. Intake of dietary vitamin C and several food groups high in vitamin C content were inversely related to hypertension, whereas supplemental vitamin C was not. In conclusion, plasma ascorbic acid and the a priori diet quality score independently predict hypertension. This suggests that hypertension risk is reduced by improving overall diet quality and/or vitamin C status. The inverse association seen for dietary but not for supplemental vitamin C suggests that vitamin C status is preferably improved by eating foods rich in vitamin C, in addition to not smoking and other dietary habits that prevent ascorbic acid from depletion.

Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation

We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10(-11) to 5.0 × 10(-21)). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10(-6)). Our results provide new evidence for the role of DNA methylation in blood pressure regulation.

Serum Urate and Incident Cardiovascular Disease: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

OBJECTIVE

There is controversy about whether serum urate (sUA) predicts future cardiovascular disease (CVD) independently of classical risk factors, and the age at which any prediction starts. We studied the sUA-CVD association among generally healthy adults.

METHODS

CARDIA recruited 5115 black and white individuals aged 18-30 years in 1985-1986 (year-0). Fatal and nonfatal CVD events by year 27 (n = 164) were ascertained during annual contacts and classified using medical records. The association with sUA (year-0, 10, 15 and 20) was modeled using Cox proportional hazards regression, pooling over gender-specific quartiles.

RESULTS

Mean sUA concentration was higher in men than women, but increased over time in both genders. Those with elevated sUA had worse metabolic profiles that substantially deteriorated over time. Adjusting for demographic and lifestyle factors (the minimal model), baseline sUA concentration was positively associated with incident CVD (hazard ratio (HR) per mg/dL = 1.21; 95% confidence interval: 1.05, 1.39; P = 0.005). This positive association attenuated to nonsignificance in the full model accounting simultaneously for classical CVD risk factors (HR = 1.09; 0.94, 1.27; P = 0.24). Both the minimal and full models appeared to show stronger associations (than year-0 sUA) between year-10 sUA and incident CVD (HR = 1.27 and 1.12, respectively), but sUA was not statistically significant in the full model. Despite fewer events, year-15 sUA showed a significant sUA-CVD association pattern, with minimal model association magnitude comparable to year-10, and remained significant in the full model (HR = 1.19; 1.02, 1.40; P = 0.03). Hyperuricemia at year-15 strongly predicted CVD risk (HR = 2.11; 1.34, 3.33; P = 0.001), with some attenuation in the full model (HR = 1.68; P = 0.04).

CONCLUSIONS

sUA may be an early biomarker for CVD in adults entering middle age. The prediction of CVD by sUA appeared to strengthen with aging. The potential complex relation of sUA with deterioration of a cluster of metabolic abnormalities warrants future exploration.

High-Density Lipoprotein Subclasses and Noncardiovascular, Noncancer Chronic Inflammatory-Related Events Versus Cardiovascular Events: The Multi-Ethnic Study of Atherosclerosis

Background

High-density lipoprotein (HDL) particles have properties beyond reverse cholesterol transport. We hypothesized that their protection extends to inflammation-related disease. The predictive value of HDL particle subclasses and inflammatory markers was studied for noncardiovascular, noncancer chronic inflammation–related death and hospitalization, and for incident cardiovascular disease (CVD).

Methods and Results

A multiethnic, multicenter, prospective observational study was conducted in 6475 men and women (aged 45 to 84 years) free of known CVD at baseline with median follow-up of 10.1 years. Fasting venous samples were analyzed for baseline lipid profile and lipoprotein particles. We focused on the HDL family of variables (small-, medium-, and large-diameter HDL particles and HDL cholesterol). Analyses identified the sum of small- plus medium-diameter HDL particles as important. Small- plus medium-diameter HDL particles were inversely associated with diagnostic code–based noncardiovascular, noncancer chronic inflammation–related death and hospitalization (n=1054) independent of covariates: relative risk per SD 0.85 (95% CI: 0.79 to 0.91, P<0.0001). Small- plus medium-diameter HDL particles were also associated with adjudicated fatal and nonfatal coronary heart disease events (n=423): relative risk per SD 0.88 (95% CI 0.77 to 0.98, P=0.02).

Conclusions

Small- plus medium-diameter HDL particles are an independent predictor for noncardiovascular, noncancer chronic inflammation–related death and hospitalization and for coronary heart disease events in subjects initially free of overt CVD. These findings support the hypothesis that smaller HDL particles of diameter <9.4 nm have anti-inflammatory properties in the general population.

Effects of calcium supplementation on biomarkers of inflammation and oxidative stress in colorectal adenoma patients: a randomized controlled trial

Inflammation and oxidative stress play important roles in colorectal carcinogenesis. There is strong evidence that calcium reduces risk for colorectal neoplasms, possibly through its ability to bind bile acids and prevent their colonic toxicity (which occurs via an oxidative mechanism and results in an inflammatory response). In a previously reported pilot, randomized, controlled trial among sporadic colorectal adenoma patients we found that those on 2.0 g/day of calcium, relative to those on placebo, had an estimated drop in a combined cytokine z-score of 48% (P = 0.18) over 6 months. To follow-up these promising preliminary findings, we tested the efficacy of two doses of supplemental calcium (1.0 or 2.0 g/day) relative to placebo on modulating circulating biomarkers of inflammation [C-reactive protein (CRP) and 10 cytokines] and oxidative stress (F2-isoprostanes) over a 4-month treatment period among 193 patients with previous sporadic, colorectal adenoma in a randomized, double-blinded, placebo-controlled clinical trial. The inflammation markers were measured in plasma using electrochemiluminescence detection-based immunoassays, and F2-isoprostanes were measured in plasma using gas chromatography-mass spectrometry. Over a 4-month treatment period, we found no appreciable effects of calcium on CRP, cytokines, or F2-isoprostanes (P > 0.4), overall or within strata of several major risk factors for colorectal carcinogenesis, such as body mass index and regular use of nonsteroidal anti-inflammatory drugs. Overall, our results provide no evidence that calcium supplementation favorably modulates concentrations of circulating biomarkers of inflammation or oxidative stress over 4 months among patients with a previous colorectal adenoma.

Glycated hemoglobin and incident type 2 diabetes in singaporean chinese adults: the Singapore Chinese health study

Background

The American Diabetes Association recently included glycated hemoglobin in the diagnostic criteria for diabetes, but research on the utility of this biomarker in Southeast Asians is scant. The aim of this study was to evaluate the association between percent HbA1c and incident diabetes in an Asian population of adult men and women without reported diabetes.

Methods

Data analysis of 5,770 men and women enrolled in the Singapore Chinese Health Study who provided a blood sample at the follow-up I visit (1999–2004) and had no cancer and no reported history of diabetes or cardiovascular disease events. Diabetes was defined as self-report of physician diagnosis, identified at the follow-up II visit (2006–2010).

Results

Hazard ratios (and 95% confidence intervals) for incident diabetes by 5 categories of HbA1c were estimated with Cox regression models and continuous HbA1c with cubic spline analysis. Compared to individuals with an HbA1c ≤ 5.7% (≤39 mmol/mol), individuals with HbA1c 5.8–5.9% (40–41 mmol/mol), 6.0–6.1% (42–43 mmol/mol), 6.2–6.4% (44–47 mmol/mol), and ≥ 6.5% (≥48 mmol/mol) had significantly increased risk for incident diabetes during follow-up. In cubic spline analysis, levels below 5.7% HbA1c were not significantly associated with incident diabetes.

Conclusions

Our study found a strong and graded association with HbA1c 5.8% and above with incident diabetes in Chinese men and women.

Hemoglobin a1c and the progression of coronary artery calcification among adults without diabetes

OBJECTIVE

Higher levels of hemoglobin A1c (HbA1c) are associated with increased cardiovascular disease risk among individuals without diabetes and may also be positively associated with coronary artery calcification (CAC). This study investigated the association of HbA1c with CAC progression in the Coronary Artery Risk Development in Young Adults study.

RESEARCH DESIGN AND METHODS

We included 2,076 participants with HbA1c and noncontrast computed tomography (CT) assessed at baseline (2005-2006), and CT repeated 5 years later (2010-2011). CAC progression was defined as 1) incident CAC (increase >0 Agatston units among those with no CAC at baseline), 2) any CAC progression (increase >10 Agatston units between examinations), and 3) advanced CAC progression (increase >100 Agatston units between examinations).

RESULTS

During the 5-year follow-up period, 12.9% of participants without baseline CAC developed incident CAC; among all participants, 18.2% had any CAC progression and 5.4% had advanced CAC progression. Higher HbA1c was associated with incident CAC (risk ratio [RR] = 1.45; 95% CI 1.02, 2.06), any CAC progression (RR = 1.51; 95% CI 1.16, 1.96), and advanced CAC progression (RR = 2.42; 95% CI 1.47, 3.99) after adjustment for sociodemographic factors. Additional adjustment for cardiovascular risk factors attenuated the associations of HbA1c with incident CAC (RR = 1.05; 95% CI 0.74, 1.49) and any CAC progression (RR = 1.13; 95% CI 0.87, 1.47). In contrast, the association of HbA1c with advanced CAC progression persisted in multivariable adjusted models (RR = 1.78; 95% CI 1.08, 2.95).

CONCLUSIONS

Higher HbA1c was independently associated with advanced CAC progression among individuals without diabetes, while the associations with incident CAC and any CAC progression were accounted for by other established cardiovascular risk factors.

Glycated hemoglobin and all-cause and cause-specific mortality in Singaporean Chinese without diagnosed diabetes: the Singapore Chinese Health Study

OBJECTIVE

Glycated hemoglobin (HbA₁c) is a robust biomarker of the preceding 2 to 3 months average blood glucose level. The aim of this study was to examine the association between HbA₁c and mortality in a cohort of Southeast Asians.

RESEARCH DESIGN AND METHODS

Analysis of 7,388 men and women, mean age 62 years, from the Singapore Chinese Health Study who provided a blood sample at the follow-up I visit (1999-2004) and reported no history of diabetes, previous adverse cardiovascular events, or cancer. A total of 888 deaths were identified through 31 December 2011 via registry linkage. Participants represented a random study sample of potential control subjects for a nested case-control genome-wide association study of type 2 diabetes in the population. Hazard ratios (HRs) for all-cause and cause-specific mortality by six categories of HbA1c were estimated with Cox regression models.

RESULTS

Relative to participants with an HbA₁c of 5.4-5.6% (36-38 mmol/mol), participants with HbA₁c ≥6.5% (≥48 mmol/mol) had an increased risk of all-cause, cardiovascular, and cancer mortality during an average of 10.1 years of follow-up; HRs (95% CIs) were 1.96 (1.56-2.46), 2.63 (1.77-3.90), and 1.51 (1.04-2.18), respectively. No level of HbA1c was associated with increased risk of respiratory mortality. Levels <6.5% HbA₁c were not associated with mortality during follow-up. The results did not materially change after excluding observation of first 3 years post-blood draw.

CONCLUSIONS

HbA₁c levels consistent with undiagnosed type 2 diabetes (≥6.5%) are associated with an increased risk of all-cause and cause-specific mortality in Chinese men and women.

Abstract 3277: A low plasma mitchondrial DNA copy number is associated with increased breast cancer risk

Previous studies have shown that plasma mtDNA can be separated into two fractions; a supernatant form that is cell-free and a pelleted form that is thought to be platelet associated. These fractions of plasma mtDNA should be measured in studies evaluating the role of plasma mtDNA as biomarkers for early detection or susceptibility to various cancers. Though one case-control study has shown lower plasma mitochondrial DNA (mtDNA) copy number to be associated with increased breast cancer risk this study did not evaluate the two fractions of plasma mtDNA. Hence, the role of plasma mtDNA in determining breast cancer risk was investigated further. We conducted a case-control study of 29 breast cancer cases and 28 cancer free controls to evaluate the association between (a) plasma mtDNA copy number and (b) peripheral blood leucocyte mtDNA copy number and breast cancer risk. Plasma obtained from the breast cancer cases and controls was centrifuged further at 18,000 g for 10 minutes to separate the plasma into the supernatant and pelleted fractions. Using flow cytometry, we stained the pelleted fraction of the plasma with Annexin V and CD61 to determine the cellular source of the plasma pellet. DNA from the two plasma fractions and the buffy coat was extracted using the Qiagen DNAesy DNA extraction kit. Nuclear DNA (18s) and mitochondrial DNA (ND1) copy numbers were measured using quantitative real time PCR. We used a two-sample independent t test to evaluate the difference in mtDNA in the two plasma fractions and mtDNA copy number in peripheral blood leucocytes among breast cancer cases and controls. The plasma pellet fraction predominantly contained particles that were 1-3 microns in size that stained positively for both Annexin V and CD61 indicating that these particles were platelet derived microparticles. The mtDNA in the plasma pellet accounted for 96% of all the plasma mtDNA seen in both cases and controls. Both the plasma supernatant mtDNA (2601034 mtDNA copies/ml of plasma vs. 4700446 mtDNA copies/ml of plasma; p = 0.004) and plasma pellet mtDNA (67787069 mtDNA copies/ml of plasma vs. 112883929 mtDNA copies/ml of plasma; p = 0.001) were significantly lower in the breast cancer cases as compared to controls. Peripheral blood leucocytes mtDNA copy number was not associated with breast cancer risk (4.27 vs. 3.73; p=0.14). There was no correlation between mtDNA in peripheral blood and the various fractions of plasma mtDNA (r= -0.08 - 0.07; p = 0.55 - 0.63). This is the first study to demonstrate platelet derived microparticles as the source of the plasma pellet mtDNA. This study shows that both the supernatant and pelleted fractions of plasma mtDNA are associated with breast cancer risk. Peripheral blood leucocytes mtDNA was not associated with breast cancer risk and was not correlated with plasma mtDNA. Future studies are needed to confirm these associations and evaluate possible mechanisms through which plasma mtDNA copy number is associated with breast cancer risk.

Citation Format: Bharat Thyagarajan, Helene Barcelo, Kristin E. Anderson, Karen Swenson, Heather Nelson, Myron D. Gross. A low plasma mitchondrial DNA copy number is associated with increased breast cancer risk. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3277. doi:10.1158/1538-7445.AM2014-3277

Association of exome sequences with plasma C-reactive protein levels in >9000 participants

C-reactive protein (CRP) concentration is a heritable systemic marker of inflammation that is associated with cardiovascular disease risk. Genome-wide association studies have identified CRP-associated common variants associated in ∼25 genes. Our aims were to apply exome sequencing to (1) assess whether the candidate loci contain rare coding variants associated with CRP levels and (2) perform an exome-wide search for rare variants in novel genes associated with CRP levels. We exome-sequenced 6050 European-Americans (EAs) and 3109 African-Americans (AAs) from the NHLBI-ESP and the CHARGE consortia, and performed association tests of sequence data with measured CRP levels. In single-variant tests across candidate loci, a novel rare (minor allele frequency = 0.16%) CRP-coding variant (rs77832441-A; p.Thr59Met) was associated with 53% lower mean CRP levels (P = 2.9 × 10(-6)). We replicated the association of rs77832441 in an exome array analysis of 11 414 EAs (P = 3.0 × 10(-15)). Despite a strong effect on CRP levels, rs77832441 was not associated with inflammation-related phenotypes including coronary heart disease. We also found evidence for an AA-specific association of APOE-ε2 rs7214 with higher CRP levels. At the exome-wide significance level (P < 5.0 × 10(-8)), we confirmed associations for reported common variants of HNF1A, CRP, IL6R and TOMM40-APOE. In gene-based tests, a burden of rare/lower frequency variation in CRP in EAs (P ≤ 6.8 × 10(-4)) and in retinoic acid receptor-related orphan receptor α (RORA) in AAs (P = 1.7 × 10(-3)) were associated with CRP levels at the candidate gene level (P < 2.0 × 10(-3)). This inquiry did not elucidate novel genes, but instead demonstrated that variants distributed across the allele frequency spectrum within candidate genes contribute to CRP levels.

Dietary patterns and mortality in a Chinese population

BACKGROUND

Limited research has examined the association between dietary patterns and mortality, especially in non-Western populations.

OBJECTIVE

We examined the association of dietary patterns with all-cause mortality and cause-specific mortality in the Singapore Chinese Health Study, which included a unique ethnic population with strong Western and South Asian cultural influences.

DESIGN

We conducted a prospective data analysis of the Singapore Chinese Health Study, which included 52,584 Chinese men and women (aged 45-74 y) who were free of diabetes, cardiovascular disease (CVD), and cancer at baseline (1993-1998) and followed through 2011 with 10,029 deaths. The following 2 major dietary patterns were identified by using a principal components analysis: a vegetable-, fruit-, and soy-rich (VFS) pattern and a dim sum- and meat-rich (DSM) dietary pattern. Pattern scores for each participant were calculated and examined with all-cause and cause-specific mortality risks by using a Cox proportional hazards regression.

RESULTS

The VFS pattern was inversely associated with all-cause mortality and each cause-specific category (CVD, cancer, and respiratory) of mortality during the follow-up period. Compared with the lowest quintile of the VFS pattern, HRs for quintiles 2-5 for all-cause mortality were 0.90, 0.79, 0.80, and 0.75, respectively (P-trend < 0.0001). The DSM pattern was positively associated with CVD mortality in the whole population (HR for fifth quintile compared with first quintile: 1.23; 95% CI: 1.07, 1.40; P-trend = 0.001). Positive associations between the DSM pattern and cancer and all-cause mortality were only present in ever-smokers. In ever-smokers, relative to the first quintile, HRs for quintiles 2-5 of the DSM pattern for all-cause mortality were 1.04, 1.04, 1.13, and 1.24, respectively (P-trend < 0.0001). Similarly, HRs for quintiles 2-5 for cancer mortality were 1.08, 1.03, 1.25, and 1.34, respectively (P-trend < 0.0001). The DSM pattern was not associated with respiratory mortality.

CONCLUSION

Dietary patterns are strongly associated with mortality in Chinese Singaporeans.

Multiple nonglycemic genomic loci are newly associated with blood level of glycated hemoglobin in East Asians

Glycated hemoglobin A1c (HbA1c) is used as a measure of glycemic control and also as a diagnostic criterion for diabetes. To discover novel loci harboring common variants associated with HbA1c in East Asians, we conducted a meta-analysis of 13 genome-wide association studies (GWAS; N = 21,026). We replicated our findings in three additional studies comprising 11,576 individuals of East Asian ancestry. Ten variants showed associations that reached genome-wide significance in the discovery data set, of which nine (four novel variants at TMEM79 [P value = 1.3 × 10(-23)], HBS1L/MYB [8.5 × 10(-15)], MYO9B [9.0 × 10(-12)], and CYBA [1.1 × 10(-8)] as well as five variants at loci that had been previously identified [CDKAL1, G6PC2/ABCB11, GCK, ANK1, and FN3KI]) showed consistent evidence of association in replication data sets. These variants explained 1.76% of the variance in HbA1c. Several of these variants (TMEM79, HBS1L/MYB, CYBA, MYO9B, ANK1, and FN3K) showed no association with either blood glucose or type 2 diabetes. Among individuals with nondiabetic levels of fasting glucose (<7.0 mmol/L) but elevated HbA1c (≥6.5%), 36.1% had HbA1c <6.5% after adjustment for these six variants. Our East Asian GWAS meta-analysis has identified novel variants associated with HbA1c as well as demonstrated that the effects of known variants are largely transferable across ethnic groups. Variants affecting erythrocyte parameters rather than glucose metabolism may be relevant to the use of HbA1c for diagnosing diabetes in these populations.

A comparison of live counseling with a web-based lifestyle and medication intervention to reduce coronary heart disease risk: a randomized clinical trial

IMPORTANCE

Most primary care clinicians lack the skills and resources to offer effective lifestyle and medication (L&M) counseling to reduce coronary heart disease (CHD) risk. Thus, effective and feasible CHD prevention programs are needed for typical practice settings.

OBJECTIVE

To assess the effectiveness, acceptability, and cost-effectiveness of a combined L&M intervention to reduce CHD risk offered in counselor-delivered and web-based formats.

DESIGN, SETTING, AND PARTICIPANTS

A comparative effectiveness trial in 5 diverse family medicine practices in North Carolina. Participants were established patients, aged 35 to 79 years, with no known cardiovascular disease, and at moderate to high risk for CHD (10-year Framingham Risk Score [FRS], ≥10%).

INTERVENTIONS

Participants were randomized to counselor-delivered or web-based format, each including 4 intensive and 3 maintenance sessions. After randomization, both formats used a web-based decision aid showing potential CHD risk reduction associated with L&M risk-reducing strategies. Participants chose the risk-reducing strategies they wished to follow.

MAIN OUTCOMES AND MEASURES

The primary outcome was within-group change in FRS at 4-month follow-up. Other measures included standardized assessments of blood pressure, blood lipid levels, lifestyle behaviors, and medication adherence. Acceptability and cost-effectiveness were also assessed. Outcomes were assessed at 4 and 12 months.

RESULTS

Of 2274 screened patients, 385 were randomized (192 counselor; 193 web): mean age, 62 years; 24% African American; and mean FRS, 16.9%. Follow-up at 4 and 12 months included 91% and 87% of the randomized participants, respectively. There was a sustained reduction in FRS at both 4 months (primary outcome) and 12 months for both counselor-based (-2.3% [95% CI, -3.0% to -1.6%] and -1.9% [95% CI, -2.8% to -1.1%], respectively) and web-based groups (-1.5% [95% CI, -2.2% to -0.9%] and -1.7% [95% CI, -2.6% to -0.8%] respectively). At 4 months, the adjusted difference in FRS between groups was -1.0% (95% CI, -1.8% to -0.1%) (P = .03), and at 12 months, it was -0.6% (95% CI, -1.7% to 0.5%) (P = .30). The 12-month costs from the payer perspective were $207 and $110 per person for the counselor- and web-based interventions, respectively.

CONCLUSIONS AND RELEVANCE

Both intervention formats reduced CHD risk through 12-month follow-up. The web format was less expensive.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01245686.

Diet quality and markers of endothelial function: the CARDIA study

BACKGROUND AND AIM

Dietary patterns are associated cross-sectionally with cellular adhesion molecules (CAMs). We studied prospective associations of three dietary patterns with CAMs.

METHODS AND RESULTS

In the Coronary Artery Risk Development in Young Adults (CARDIA) study, diet was assessed at years 0 (1985-86) and 7 (1992-93) examinations. Four circulating CAMs (E-selectin, P-selectin, soluble intercellular adhesion molecule 1 (sICAM-1), and vascular cellular adhesion molecule (VCAM)) were assayed at years 7 and 15 (2000-01). We created one index score "A Priori Diet Quality Score" and derived dietary patterns using principal components analysis (PCA). Multivariable linear regression models predicted year 15 CAMs from averaged (year 0/7) dietary patterns. The A Priori Diet Quality Score rated 46 food groups beneficial, neutral or adverse based on hypothesized health effects. We derived two PCA dietary patterns: "fruit and vegetables (FV)" (high intakes of fruit, vegetables, and whole grains) and "meat" (high intakes of red meat, refined grain, and butter). All dietary patterns were related to E-selectin and sICAM-1. P-selectin was not related to the FV dietary pattern. VCAM was only related to the A Priori Diet Quality Score. Strongest associations were for the meat dietary pattern with E-selectin (effect size 28% of an SD (+3.9/13.7 ng/mL)) and P-selectin (effect size 37% of an SD (+4.1/11.2 ng/mL)) and the A Priori Diet Quality Score with sICAM-1 (effect size 34% of an SD (-15.1/44.7 ng/mL)) and VCAM (effect size of 26% of an SD (-45.1/170.3 ng/mL)).

CONCLUSION

This prospective analysis suggests that dietary patterns are associated with CAMs.

Large multiethnic Candidate Gene Study for C-reactive protein levels: identification of a novel association at CD36 in African Americans

C-reactive protein (CRP) is a heritable biomarker of systemic inflammation and a predictor of cardiovascular disease (CVD). Large-scale genetic association studies for CRP have largely focused on individuals of European descent. We sought to uncover novel genetic variants for CRP in a multiethnic sample using the ITMAT Broad-CARe (IBC) array, a custom 50,000 SNP gene-centric array having dense coverage of over 2,000 candidate CVD genes. We performed analyses on 7,570 African Americans (AA) from the Candidate gene Association Resource (CARe) study and race-combined meta-analyses that included 29,939 additional individuals of European descent from CARe, the Women's Health Initiative (WHI) and KORA studies. We observed array-wide significance (p < 2.2 × 10(-6)) for four loci in AA, three of which have been reported previously in individuals of European descent (IL6R, p = 2.0 × 10(-6); CRP, p = 4.2 × 10(-71); APOE, p = 1.6 × 10(-6)). The fourth significant locus, CD36 (p = 1.6 × 10(-6)), was observed at a functional variant (rs3211938) that is extremely rare in individuals of European descent. We replicated the CD36 finding (p = 1.8 × 10(-5)) in an independent sample of 8,041 AA women from WHI; a meta-analysis combining the CARe and WHI AA results at rs3211938 reached genome-wide significance (p = 1.5 × 10(-10)). In the race-combined meta-analyses, 13 loci reached significance, including ten (CRP, TOMM40/APOE/APOC1, HNF1A, LEPR, GCKR, IL6R, IL1RN, NLRP3, HNF4A and BAZ1B/BCL7B) previously associated with CRP, and one (ARNTL) previously reported to be nominally associated with CRP. Two novel loci were also detected (RPS6KB1, p = 2.0 × 10(-6); CD36, p = 1.4 × 10(-6)). These results highlight both shared and unique genetic risk factors for CRP in AA compared to populations of European descent.

Joint effects of known type 2 diabetes susceptibility loci in genome-wide association study of Singapore Chinese: the Singapore Chinese health study

BACKGROUND

Genome-wide association studies (GWAS) have identified genetic factors in type 2 diabetes (T2D), mostly among individuals of European ancestry. We tested whether previously identified T2D-associated single nucleotide polymorphisms (SNPs) replicate and whether SNPs in regions near known T2D SNPs were associated with T2D within the Singapore Chinese Health Study.

METHODS

2338 cases and 2339 T2D controls from the Singapore Chinese Health Study were genotyped for 507,509 SNPs. Imputation extended the genotyped SNPs to 7,514,461 with high estimated certainty (r(2)>0.8). Replication of known index SNP associations in T2D was attempted. Risk scores were computed as the sum of index risk alleles. SNPs in regions ± 100 kb around each index were tested for associations with T2D in conditional fine-mapping analysis.

RESULTS

Of 69 index SNPs, 20 were genotyped directly and genotypes at 35 others were well imputed. Among the 55 SNPs with data, disease associations were replicated (at p<0.05) for 15 SNPs, while 32 more were directionally consistent with previous reports. Risk score was a significant predictor with a 2.03 fold higher risk CI (1.69-2.44) of T2D comparing the highest to lowest quintile of risk allele burden (p = 5.72 × 10(-14)). Two improved SNPs around index rs10923931 and 5 new candidate SNPs around indices rs10965250 and rs1111875 passed simple Bonferroni corrections for significance in conditional analysis. Nonetheless, only a small fraction (2.3% on the disease liability scale) of T2D burden in Singapore is explained by these SNPs.

CONCLUSIONS

While diabetes risk in Singapore Chinese involves genetic variants, most disease risk remains unexplained. Further genetic work is ongoing in the Singapore Chinese population to identify unique common variants not already seen in earlier studies. However rapid increases in T2D risk have occurred in recent decades in this population, indicating that dynamic environmental influences and possibly gene by environment interactions complicate the genetic architecture of this disease.

Oxidative balance score, colorectal adenoma, and markers of oxidative stress and inflammation

BACKGROUND

An oxidative balance score (OBS) that combines pro- and antioxidant exposures was previously reported to be associated with incident sporadic colorectal adenoma. We extend the previous analyses by assessing associations of the OBS and colorectal adenoma with circulating biomarkers of oxidative stress [F2-isoprostanes (FIP) and fluorescent oxidation products (FOP)], and inflammation [C-reactive protein (CRP)].

METHODS

Using pooled data from two previously conducted colonoscopy-based case-control studies of incident, sporadic colorectal adenoma (n = 365), the OBS was constructed and divided into three approximately equal intervals, with the lowest interval used as the reference. Biomarker levels were dichotomized as "high" versus "low" based on the median values among controls. Multivariable logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

For the OBS-adenoma association, the ORs (95% CIs) for the middle and highest (relative to the lowest) score intervals were 0.81 (0.46-1.43) and 0.39 (0.17-0.89), respectively. The corresponding OBS category-specific ORs (95% CIs) were 0.50 (0.25-1.01) and 0.25 (0.10-0.65) for FIP, 2.01 (1.13-3.75) and 3.48 (1.51-8.02) for FOP, and 0.57 (0.31-1.04) and 0.21 (0.09-0.49) for CRP. The ORs (95% CIs) reflecting associations of adenoma with high levels of FIP, FOP, and CRP were 1.89 (1.08-3.30), 1.82 (1.11-2.99), and 1.45 (0.88-2.40), respectively.

CONCLUSIONS

As hypothesized, the OBS was inversely associated with colorectal adenoma and circulating FIP and CRP levels. The reason for the unexpected direct OBS-FOP association is unknown.

IMPACT

These data support the use of combined measures of pro- and antioxidant exposures in studies of colorectal neoplasia.