Ethnic differences and heritability of blood pressure circadian rhythm in African and European American youth and young adults

Background: The aim of this study was to investigate whether blood pressure (BP) circadian rhythm in African Americans differed from that in European Americans. We further examined the genetic and/or environmental sources of variances of the BP circadian rhythm parameters and the extent to which they depend on ethnicity or sex. Method: Quantification of BP circadian rhythm was obtained using Fourier transformation from the ambulatory BP monitoring data of 760 individuals (mean age, 17.2 +/- 3.3; 322 twin pairs and 116 singletons; 351 African Americans). Results: BP circadian rhythm showed a clear difference by ethnic group with African Americans having a lower amplitude (P = 1.5e-08), a lower percentage rhythm (P = 2.8e-11), a higher MESOR (P = 2.5e-05) and being more likely not to display circadian rhythm (P = 0.002) or not in phase (P = 0.003). Familial aggregation was identified for amplitude, percentage rhythm and acrophase with genetic factors and common environmental factors together accounting for 23 to 33% of the total variance of these BP circadian rhythm parameters. Unique environmental factors were the largest contributor explaining up to 67--77% of the total variance of these parameters. No sex or ethnicity difference in the variance components of BP circadian rhythm was observed. Conclusion: This study suggests that ethnic differences in BP circadian rhythm already exist in youth with African Americans having a dampened circadian rhythm and better BP circadian rhythm may be achieved by changes in environmental factors

Social Media and Cardiovascular Disease

Personality subtypes and systolic blood pressure (SBP) at night are recognized predictors of cardiovascular disease among social media users. Healthy individuals (n=88, 77% female, 31% African American) were surveyed using the Media and Technology Usage and Attitudes Scale (MTUAS). Demographics, 24-hours SBP, and personality types (e.g., introvert, extravert, and blended) were used. Personality (B= 5.37, t= 2.86, p=.005) significantly predicted elevated SBP in social media users (r2= .157, F(4, 72)=3.37, p=.014). There was a significant gradient increase in nighttime SBP by personality [introvert (M=100, SD=2.1), extrovert (M=102, SD=1.7), and blended (M=111, SD=4.4); all ps.<0.05]. Negative attitudes toward using technology (B= -5.093, t= -2.390, p= .019) also significantly predicted elevated overnight SBP. Higher anxiety/dependence with mobile phones (B=.400, t= 2.49, p=.019) significantly predicted elevated nighttime SBP [r2 = 0.342 F(4, 27) = 3.505, p=.020]. Our findings indicate that a blended personality type and anxiety due to separation from or dependence on a mobile phone or internet use elevate SBP at night, increasing the risk of developing cardiovascular disease

A Genome-Wide Methylation Study of Severe Vitamin D Deficiency in African American Adolescents

To test the hypothesis that changes in DNA methylation are involved in vitamin D deficiency–related immune cell regulation using an unbiased genome-wide approach combined with a genomic and epigenomic integrative approach

DNA Methylation of the LY86 Gene is Associated With Obesity, Insulin Resistance, and Inflammation

Background: Previous genome-wide association studies (GWAS) have identified a large number of genetic variants for obesity and its related traits, representing a group of potential key genes in the etiology of obesity. Emerging evidence suggests that epigenetics may play an important role in obesity. It has not been explored whether the GWAS-identified loci contribute to obesity through epigenetics (e.g., DNA (deoxyribonucleic acid) methylation) in addition to genetics. Method: A multi-stage cross-sectional study was designed. We did a literature search and identified 117 genes discovered by GWAS for obesity and its related traits. Then we analyzed whether the methylation levels of these genes were also associated with obesity in two genome-wide methylation panels. We examined an initial panel of seven adolescent obese cases and seven age-matched lean controls, followed by a second panel of 48 adolescent obese cases and 48 age- and gender-matched lean controls. The validated CpG sites were further replicated in two independent replication panels of youth (46 vs. 46 and 230 cases vs. 413 controls, respectively) and a general population of youth, including 703 healthy subjects. Results: One CpG site in the lymphocyte antigen 86 (LY86) gene, which showed higher methylation in the obese in both the initial (p=.009) and second genome-wide DNA methylation panel (p=.008), was further validated in both replication panels (meta p=.00016). Moreover, in the general population of youth, the methylation levels of this region were significantly correlated with adiposity indices (

Obesity related methylation changes in DNA of peripheral blood leukocytes

<p>Abstract</p> <p>Background</p> <p>Despite evidence linking obesity to impaired immune function, little is known about the specific mechanisms. Because of emerging evidence that immune responses are epigenetically regulated, we hypothesized that DNA methylation changes are involved in obesity induced immune dysfunction and aimed to identify these changes.</p> <p>Method</p> <p>We conducted a genome wide methylation analysis on seven obese cases and seven lean controls aged 14 to 18 years from extreme ends of the obesity distribution and performed further validation of six CpG sites from six genes in 46 obese cases and 46 lean controls aged 14 to 30 years.</p> <p>Results</p> <p>In comparison with the lean controls, we observed one CpG site in the UBASH3A gene showing higher methylation levels and one CpG site in the TRIM3 gene showing lower methylation levels in the obese cases in both the genome wide step (<it>P </it>= 5 × 10^-6and <it>P </it>= 2 × 10^-5for the UBASH3A and the TRIM3 gene respectively) and the validation step (<it>P </it>= 0.008 and <it>P </it>= 0.001 for the UBASH3A and the TRIM3 gene respectively).</p> <p>Conclusions</p> <p>Our results provide evidence that obesity is associated with methylation changes in blood leukocyte DNA. Further studies are warranted to determine the causal direction of this relationship as well as whether such methylation changes can lead to immune dysfunction.</p> <p>See commentary: <url>http://www.biomedcentral.com/1741-7015/8/88/abstract</url></p

A 15-year longitudinal study on ambulatory blood pressure tracking from childhood to early adulthood

This study evaluates the tracking stability of office blood pressure (BP), ambulatory BP (ABP), BP variability (BPV) and nocturnal BP drops (dipping) from childhood to early adulthood, and their dependence on ethnicity, gender and family history (FH) of essential hypertension (EH). Generalized estimating equations (GEEs) were used to estimate tracking coefficients for 295 European Americans and 252 African Americans, with a maximum of 12 measurements over a 15-year period. Office BP and ABP had moderate-to-relatively high tracking coefficients (r=0.30-0.59;

Impact of breathing awareness meditation on ambulatory blood pressure and sodium handling in prehypertensive African American adolescents.

These findings demonstrate the potential beneficial impact of BAM taught by school health teachers on blood pressure control in the natural environment in African American youth at risk for development of hypertension

A longitudinal study of blood pressure variability in African-American and European American youth

Objectives High blood pressure variability is increasingly used as a predictor of target-organ damage and cardiovascular events. However, little is known about blood pressure variability changes with age and its possible sociodemographic, anthropometric, and genetic moderators. Methods Twenty-four-hour ambulatory blood pressure was measured up to 12 times over a 15-year period in 344 European Americans and 297 African-Americans with an average age of 14 years at the initial visit. Blood pressure variability was indexed by the weighted 24-h standard deviation of ambulatory blood pressure recordings. Results Both systolic and diastolic blood pressure variability increased with age and ambulatory blood pressure mean values. Men had higher levels of blood pressure variability (P Conclusion The results of the present study suggest that men and African-Americans have higher blood pressure variability than women and European Americans. Apart from these ethnicity and sex effects, blood pressure variability increases with increases in age (especially in men), ambulatory blood pressure mean values and adiposity as well as decreased socioeconomic status. J Hypertens 28: 715-722 (C) 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins