Article Text
Abstract
Introduction Determinants and correlates of a novel index of adipose tissue insulin resistance (AT-IR) (the product of fasting insulin and free fatty acid concentrations) were investigated in Japanese women without diabetes and obesity.
Research design and methods Cross-sectional associations of AT-IR with fat mass and distribution, and IR-related cardiometabolic variables were examined in 210 young and 148 middle-aged women whose average body mass index (BMI) was <23 kg/m2 and waist was <80 cm. Multivariate linear regression analyses were used to identify most important determinants of AT-IR.
Results Young and middle-aged women did not differ in AT-IR (3.5±2.7 and 3.2±2.1, respectively). In both young and middle-aged women, AT-IR was positively associated with trunk/leg fat ratio, a sophisticated measure of abdominal fat accumulation, fasting plasma glucose (FPG), fasting triglycerides (FTG), serum alanine aminotransferase and γ-glutamyl-transpeptidase (all p<0.05). Furthermore, in middle-aged but not in young women, AT-IR showed positive associations with BMI, waist, fat mass index, low-density lipoprotein cholesterol, apolipoprotein B and systolic and diastolic blood pressure (BP) (all p<0.05). AT-IR showed no association with hemoglobin A1c, high-density lipoprotein (HDL) cholesterol and apolipoprotein A1 in two groups of women. On multivariate analysis including waist, FPG, FTG, HDL cholesterol and systolic BP as independent variables, FPG, FTG and HDL cholesterol emerged as independent determinants of AT-IR in young women (cumulative R2=0.141) and waist in middle-aged women (cumulative R2=0.056). In a model which included trunk/leg fat ratio instead of waist, trunk/leg fat ratio and systolic BP were determinants of AT-IR in middle-aged women (cumulative R2=0.093). Results did not alter in young women.
Conclusions AT-IR may be a simple and useful surrogate index of adipose tissue insulin resistance even in populations without diabetes and obesity.
- adipose tissue
- insulin resistance
- metabolic syndrome
- women
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Footnotes
Contributors KK, AT, SM-I, MH, MT, MY, MK and BW collected and analyzed data. TK wrote the manuscript and KF reviewed and edited it. All authors approved the final version of the manuscript to be published. TK supervised the study, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study was approved by the Ethical Committees of Mukogawa Women’s University (No. 07-28, on 19 February 2008) and was in accordance with the tenets of the Declaration of Helsinki. All subjects were recruited as volunteers and gave written consent after the experimental procedure had been explained.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article. The ethical committee of the University does not allow us to open data except for a manuscript.