The reproducibility of ethnic differences in the proportional awake-sleep blood pressure decline among women.
A growing body of evidence indicates that African Americans (AA), on average, have a smaller proportional decline in blood pressure (BP) from waking to sleep than European Americans (EA), but this difference is largely based on correlational data from a single assessment day. The persistence of this difference over repeated sampling is not well established. The purpose of this study was to evaluate whether ethnic differences in the awake-sleep BP decline between AA and EA persisted over three monthly assessments. The subjects were 47 AA (age = 39.7 +/- 8.7) and 92 EA (age = 37.4 +/- 9.2) normotensive women. Subjects had 24-h ambulatory BP monitoring done on midweek workdays at 1-month intervals for three consecutive months. The proportional decline in BP was calculated as follows: (average awake - average sleep)/average sleep. The persistence of ethnic differences was evaluated using repeated-measures ANCOVA and by examining Bland-Altman plots. The ANCOVA results revealed that overall, the proportional decline of AA women was less than that of EA women for both SBP (P < 0.038) and DBP (P < 0.083), consistent with previous research, and that there were also no significant ethnic differences by monthly assessment. Bland-Altman plots revealed that overall and by ethnicity, the proportional decline in BP among individual subjects over the 3 months was also reproducible. These results suggest that the ethnic difference in awake-sleep BP between AA and EA women persists over time and that the awake-sleep decline in BP among individuals, whether AA or EA, is also reproducible.
Institute for Primary and Preventative Health Care, Department of Anthropology, Binghamton University, PO Box 6000, Binghamton, NY 13902-6000, USA. hvanbergelandry@binghamton.edu
Helene M
HM
Van Berge-Landry
Dana H
DH
Bovbjerg
Gary D
GD
James
D000328:Adult; D001741:Black or African American; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D001837:Body Weights and Measures; D005260:Female; D015438:Health Behavior; D006801:Humans; D008875:Middle Aged; D012890:Sleep / Q000502:physiology*; D012959:Socioeconomic Factors; D014851:Wakefulness / Q000502:physiology; D044465:White People; D016387:Women's Health