Epidemiological evidence of altered cardiac autonomic function in subjects with impaired glucose tolerance but not isolated impaired fasting glucose.
BACKGROUND
Autonomic dysfunction is present in diabetes mellitus (DM), but no study is available on alteration in cardiac autonomic function (CAF) across different glycemic statuses including normal glucose tolerance (NGT), isolated impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and DM.


OBJECTIVE
Our objective was to examine whether CAF is altered in subjects with IGT and isolated IFG.


METHODS
The study was a stratified systematic cluster sampling design within the general community.


METHODS
A total of 1440 subjects were classified as NGT (n = 983), isolated IFG (n = 163), IGT (n = 188), and DM (n = 106).


METHODS
CAF was determined by 1) standard deviation of normal-to-normal (SDNN) or RR interval, power spectrum in low and high frequency (LF, 0.04-0.15 Hz; HF, 0.15-0.40 Hz), and LF/HF ratio in supine position for 5 min; 2) ratio between 30th and 15th RR interval after standing from supine position (30/15 ratio); and 3) average heart rate change during breathing of six deep breaths for 1 min (HR(DB)).


RESULTS
Univariate analysis showed significant differences in SDNN, 30/15 ratio, HR(DB), HF power, and LF/HF ratio among subjects with NGT, isolated IFG, IGT, and DM. In multivariate analysis, none of the indices of CAF was related to isolated IFG in the reference group of NGT. IGT and DM were negatively associated with 30/15 ratio and HF power but positively associated with LF/HF ratio. In addition, DM was also related to a lower SDNN.


CONCLUSIONS
DM and IGT subjects had an impaired CAF independent of other cardiovascular risk factors. The risk of altered CAF is not apparent in subjects with isolated IFG.
Department of Family Medicine, National Cheng Kung University Hospital, 138, Sheng Li Road, Tainan, 70441, Taiwan, Republic of China.
Jin-Shang
JS
Wu
Yi-Ching
YC
Yang
Thy-Sheng
TS
Lin
Ying-Hsiang
YH
Huang
Jia-Jin
JJ
Chen
Feng-Hwa
FH
Lu
Chih-Hsing
CH
Wu
Chih-Jen
CJ
Chang
D000328:Adult; D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000453:epidemiology* / Q000378:metabolism; D001786:Blood Glucose; D003929:Diabetic Neuropathies / Q000453:epidemiology* / Q000378:metabolism; D005215:Fasting; D005260:Female; D018149:Glucose Intolerance / Q000453:epidemiology* / Q000378:metabolism; D006321:Heart / Q000294:innervation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology
D001786:Blood Glucose