Fig. 2

Figure 2 shows that lower HRV is significantly associated with lower overall beta cell response, estimated from the overall beta cell response composite score (in SD). Regression coefficients represent the difference in overall beta cell response composite score (in SD) per SD lower time-or frequency-domain HRV. Time domain HRV was estimated from SDNN, SDANN, RMSSD, SDNN index and pNN50; and frequency domain was estimated from TP, ULF, VLF, LF, and HF. Overall beta cell response composite score was estimated from C-peptidogenic index, overall insulin secretion, beta cell glucose sensitivity, beta cell potentiation factor, and beta cell rate sensitivity. Values per SD are reported in Table 1

Bold indicates P < 0.05

Variables entered in the models in addition to HRV: age, sex, educational status (low, medium, high), Matsuda Index, office systolic blood pressure, total cholesterol/HDL cholesterol ratio, use of antihypertensive or lipid-modifying medication (yes/no), BMI, smoking status (current, ever, never), and alcohol consumption status (none, low, high)

Abbreviations: SD, standard deviation; CI, confidence interval; HRV, heart rate variability, HDL, high-density lipid; BMI, body-mass index. All abbreviations for indices of HRV are presented in the Methods section.