TABLE 1

Mean (SD) or proportion of baseline characteristics of the study population and stratified by major event categories and quartiles of HRV*: the ARIC Study

VariableAll (n = 11,654)Outcome categories
2-min SDNN quartile
Incident CHD (n = 635)Incident MI (n = 346)Fatal CHD (n = 82)Non-CHD death (n = 623)Lowest (n = 2,916)Upper three (n = 8,736)
Age (years)54 (5.7)56 (5.4)56 (5.4)57 (5.52)57 (5.4)55 (5.7)53 (5.6)
Sex (% male)42676266503544
Race (% white)74787551597275
Education (% > high school)78706762627479
Current smoker (%)26374137422526
BMI (kg/m2)27.52 (5.31)28.18 (4.96)28.39 (5.30)28.52 (5.96)27.33 (6.06)28.25 (5.87)27.27 (5.09)
Glucose (mg/dl)108 (40)127 (65)129 (64)152 (98)126 (76)118 (57)105 (31)
Insulin (pmol/l)98 (196)176 (415)182 (421)271 (628)157 (491)137 (326)85 (123)
Total cholesterol (mg/dl)214 (41)226 (42)227 (42)223 (53)216 (47)219 (43)213 (41)
HDL cholesterol (mg/dl)52 (17)43 (13)44 (14)45 (15)51 (18)52 (18)52 (17)
Triglycerides (mg/dl)129 (87)161 (102)162 (104)162 (123)144 (121)145 (107)124 (79)
Systolic BP (mmHg)121 (19)129 (21)130 (22)138 (24)129 (24)125 (20)120 (18)
Diastolic BP (mmHg)73 (11)76 (13)76 (14)78 (14)76 (14)75 (12)73 (11)
Hypertension (%)33515173464430
Diabetes (%)1125273823188
Duration of diabetes*
 <1 year or unknown (%)70686593906872
 1–5 years (%)12910041112
 5–10 years (%)89120488
 >10 years (%)1014136.52139
Treated diabetes (%)*46586171655440
Mean heart rate (beat/min)68 (10)68 (12)68 (12)73 (15)71 (12)74 (12)66 (9)
Incident CHD (%)5.57.34.8
  • *

    * Among diabetes. BP, blood pressure.