Heart Rate Variability, Insulin Resistance, and Insulin Sensitivity in Japanese Adults: The Toon Health Study.
BACKGROUND
Although impaired cardiac autonomic function is associated with an increased risk of type 2 diabetes in Caucasians, evidence in Asian populations with a lower body mass index is limited.


METHODS
Between 2009-2012, the Toon Health Study recruited 1899 individuals aged 30-79 years who were not taking medication for diabetes. A 75-g oral glucose tolerance test was used to diagnose type 2 diabetes, and fasting and 2-h-postload glucose and insulin concentrations were measured. We assessed the homeostasis model assessment index for insulin resistance (HOMA-IR) and Gutt's insulin sensitivity index (ISI). Pulse was recorded for 5 min, and time-domain heart rate variability (HRV) indices were calculated: the standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive difference (RMSSD). Power spectral analysis provided frequency domain measures of HRV: high frequency (HF) power, low frequency (LF) power, and the LF:HF ratio.


RESULTS
Multivariate-adjusted logistic regression models showed decreased SDNN, RMSSD, and HF, and increased LF:HF ratio were associated significantly with increased HOMA-IR and decreased ISI. When stratified by overweight status, the association of RMSSD, HF, and LF:HF ratio with decreased ISI was also apparent in non-overweight individuals. The interaction between LF:HF ratio and decreased ISI in overweight individuals was significant, with the odds ratio for decreased ISI in the highest quartile of LF:HF ratio in non-overweight individuals being 2.09 (95% confidence interval, 1.41-3.10).


CONCLUSIONS
Reduced HRV was associated with insulin resistance and lower insulin sensitivity. Decreased ISI was linked with parasympathetic dysfunction, primarily in non-overweight individuals.
Department of Community Health Systems Nursing, Ehime University Graduate School of Medicine.
Isao
I
Saito
Shinichi
S
Hitsumoto
Koutatsu
K
Maruyama
Wataru
W
Nishida
Eri
E
Eguchi
Tadahiro
T
Kato
Ryoichi
R
Kawamura
Yasunori
Y
Takata
Hiroshi
H
Onuma
Haruhiko
H
Osawa
Takeshi
T
Tanigawa
D000328:Adult; D000368:Aged; D044466:Asian People / Q000706:statistics & numerical data; D001786:Blood Glucose / Q000032:analysis* / Q000378:metabolism; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology; D005260:Female; D018149:Glucose Intolerance / Q000097:blood; D005951:Glucose Tolerance Test; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D007564:Japan; D008019:Life Style; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis
D001786:Blood Glucose; D007328:Insulin