Table 2. Sex- and age-adjusted meansa grouped according to quartiles of SDNN (n = 1899).
| Quartile of SDNN |
P for difference |
||||
| Q1 (Low) | Q2 | Q3 | Q4 (High) | ||
| Age, years | 63.7 | 58.1 | 54.4 | 53.7 | <0.001 |
| Sex, % men | 33.4 | 32.6 | 32.8 | 38.5 | 0.17 |
| Body mass index, kg/m2 | 23.4 | 23.1 | 22.9 | 22.8 | 0.025 |
| Waist circumference, cm | 84.3 | 83.5 | 82.3 | 82.7 | 0.004 |
| Systolic blood pressure, mm Hg | 127.0 | 125.7 | 125.0 | 125.3 | 0.38 |
| Diastolic blood pressure, mm Hg | 77.3 | 76.6 | 75.6 | 74.5 | 0.001 |
| Triglyceridesa, mmol/L | 1.07 | 1.09 | 1.02 | 1.02 | 0.062 |
| LDL-cholesterol, mmol/L | 3.09 | 3.18 | 3.09 | 3.06 | 0.11 |
| HDL-cholesterol, mmol/L | 1.56 | 1.57 | 1.57 | 1.60 | 0.26 |
| Total cholesterol, mmol/L | 5.31 | 5.39 | 5.28 | 5.31 | 0.23 |
| Fasting glucosea, mmol/L | 5.17 | 5.11 | 5.08 | 5.09 | 0.043 |
| Fasting insulina, mmol/L | 36.0 | 34.5 | 32.7 | 32.4 | 0.019 |
| HOMA-IRa | 1.19 | 1.13 | 1.06 | 1.05 | 0.009 |
| Gutt’s ISIa | 1.76 | 1.88 | 1.89 | 1.95 | <0.001 |
| Medication for hypertension, % | 21.7 | 20.0 | 18.1 | 20.9 | 0.50 |
| Medication for dyslipidemia, % | 15.2 | 11.8 | 12.2 | 13.0 | 0.39 |
| Current smoker, % | 9.9 | 9.8 | 8.7 | 6.9 | 0.32 |
| Regular drinker, % | 51.8 | 48.9 | 52.6 | 53.6 | 0.44 |
| Physical activity, METs·h/day | 35.3 | 35.7 | 35.7 | 35.9 | 0.27 |
HDL, high-density lipoprotein; HOMA-IR, homeostasis model assessment index for insulin resistance; ISI, insulin sensitivity index; LDL, low-density lipoprotein; METs, metabolic equivalents; SDNN, standard deviation of normal-to-normal intervals.
Values are adjusted for sex and age by analysis of covariance. Age and sex values are shown as crude means and percentages.
aRepresented as geometric means.