Objective: Impaired baroreflex function is an early indicator of cardiovascular autonomic
imbalance. Patients with type 2 diabetes mellitus (T2D) have decreased baroreflex
sensitivity (BRS), however, whether the neural BRS (nBRS) and mechanical component
of the BRS is altered in those with high metabolic risk (HMR, impaired fasting glucose
and metabolic syndrome) or with overt T2D, is unknown. We examined this in a community-based
observational study, the Paris Prospective Study III (PPS3). Approach and Results:
In 7626 adults aged 50 to 75 years, resting nBRS (estimated by low-frequency gain,
from carotid distension rate and RR [time elapsed between two successive R waves]
intervals) and mechanical BRS were measured by high-precision carotid echotracking.
The associations between overt T2D or HMR as compared with subjects with normal glucose
metabolism and nBRS or mechanical BRS were quantified using multivariable linear regression
analysis. There were 319 subjects with T2D (61 +/- 6 years, 77% male), 1450 subjects
with HMR (60 +/- 6 years, 72% male), and 5857 subjects with normal glucose metabolism
(59 +/- 6 years, 57% male). Compared with normal glucose metabolism, nBRS was significantly
lower in HMR subjects (beta=-0.07 [95% CI, -0.12 to -0.01]; P=0.029) and in subjects
with T2D (beta=-0.18 [95% CI, -0.29 to -0.07]; P=0.002) after adjustment for confounding
and mediating factors. Subgroup analysis suggests significant and independent alteration
in mechanical BRS only among HMR patients who had both impaired fasting glucose and
metabolic syndrome. Conclusions: In this community-based study of individuals aged
50 to 75, a graded decrease in nBRS was observed in HMR subjects and patients with
overt T2D as compared with normal glucose metabolism subjects.
