TY - JOUR
T1 - Ethnic differences and heritability of heart rate variability in African- and European American youth
AU - Wang, Xiaoling
AU - Thayer, Julian F.
AU - Treiber, Frank
AU - Snieder, Harold
N1 - Funding Information:
This study was supported by Grants HL56622 and HL69999 from the National Heart, Lung, and Blood Institute, Bethesda, Maryland. Dr. Wang is also funded by the American Heart Association, Dallas, Texas (0425447B).
PY - 2005/10/15
Y1 - 2005/10/15
N2 - This study investigated whether heart rate variability (HRV) in young African-Americans differed from that in young European Americans. It further examined the genetic and/or environmental sources of HRV variance and to what extent they depend on ethnicity or gender in young twins. Subjects were available from 1 data set including 166 subjects (mean age 16 ± 2 years; 63 African-Americans) and another including 219 twins (11 singletons [4 African-Americans] and 104 pairs [42 African-Americans]; mean age 15 ± 2 years). HRV was measured over 256 RR intervals in a supine position. Two time-domain variables, the SD of normal RR intervals (SDNN) and the root-mean-square of successive differences (RMSSD) of normal RR intervals, and 3 frequency-domain variables, high-frequency (HF) power, low-frequency (LF) power, and the LF power/HF power ratio, were used. African-Americans had higher RMSSDs (p <0.01) and HF power (p = 0.047) and lower LF power/HF power ratios (p <0.01) than European Americans. These differences remained significant after adjusting for covariates. All HRV parameters were heritable; estimated heritability ranged from 32% to 71%. Model fitting showed no ethnic or gender differences for any measure. SDNN, RMSSD, and HF power were strongly correlated (r values >0.8). One factor explaining >90% of the variance for all 3 measures was identified. The heritability of this combined HRV score was 70%. In conclusion, this study suggests that ethnic differences in HRV already exist in youth, with African-Americans having greater HRV than European Americans. High heritability estimates for HRV measures were observed, and no differences in HRV heritability estimates were noted for ethnicity or gender.
AB - This study investigated whether heart rate variability (HRV) in young African-Americans differed from that in young European Americans. It further examined the genetic and/or environmental sources of HRV variance and to what extent they depend on ethnicity or gender in young twins. Subjects were available from 1 data set including 166 subjects (mean age 16 ± 2 years; 63 African-Americans) and another including 219 twins (11 singletons [4 African-Americans] and 104 pairs [42 African-Americans]; mean age 15 ± 2 years). HRV was measured over 256 RR intervals in a supine position. Two time-domain variables, the SD of normal RR intervals (SDNN) and the root-mean-square of successive differences (RMSSD) of normal RR intervals, and 3 frequency-domain variables, high-frequency (HF) power, low-frequency (LF) power, and the LF power/HF power ratio, were used. African-Americans had higher RMSSDs (p <0.01) and HF power (p = 0.047) and lower LF power/HF power ratios (p <0.01) than European Americans. These differences remained significant after adjusting for covariates. All HRV parameters were heritable; estimated heritability ranged from 32% to 71%. Model fitting showed no ethnic or gender differences for any measure. SDNN, RMSSD, and HF power were strongly correlated (r values >0.8). One factor explaining >90% of the variance for all 3 measures was identified. The heritability of this combined HRV score was 70%. In conclusion, this study suggests that ethnic differences in HRV already exist in youth, with African-Americans having greater HRV than European Americans. High heritability estimates for HRV measures were observed, and no differences in HRV heritability estimates were noted for ethnicity or gender.
UR - http://www.scopus.com/inward/record.url?scp=26244446786&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=26244446786&partnerID=8YFLogxK
U2 - 10.1016/j.amjcard.2005.06.050
DO - 10.1016/j.amjcard.2005.06.050
M3 - Article
C2 - 16214458
AN - SCOPUS:26244446786
SN - 0002-9149
VL - 96
SP - 1166
EP - 1172
JO - American Journal of Cardiology
JF - American Journal of Cardiology
IS - 8
ER -