Association of estrogen receptor-alpha gene polymorphisms with cardiac autonomic nervous activity in healthy young Japanese males.
BACKGROUND This study examined the association between estrogen receptor α gene (ESR1) polymorphisms and blood pressure (BP), heart rate (HR) and autonomic modulation of HR in a sample population. STUDY DESIGN Two hundred thirty-two young healthy women were selected, and those using oral contraceptives (OC) were compared with nonusers (control group). Short-term HR variability (HRV) was evaluated in both the supine and sitting positions using temporal indices rMSSD [square root of the mean squared differences of successive R-R intervals (RRi) divided by the number of RRi minus one], SDNN (root mean square of differences from mean RRi, divided by the number of RRi) and frequency domain methods. Power spectral components were reported at low frequency (LF) and high frequency (HF) and as LF/HF ratio. ESR1 c.454-397T>C (rs2234693) and c.454-351A>G (rs9340799) polymorphisms were determined by polymerase chain reaction and fragment restriction analysis. RESULTS The ESR1 T>C and A>G polymorphisms had no effect on HR, rMSSD, SDNN, LF, HF or LF/HF ratio (supine or sitting), independently of OC use. The ESR1 T-A, T-G, C-A and C-G haplotypes were not associated with HR, BP or HRV. CONCLUSIONS ESR1 variants had no effect on the autonomic modulation of HR in young women users and nonusers of OC and may not be implicated in cardiovascular risk in young women.