Effects of Aging on Visceral and Subcutaneous Fat Areas and on Homeostasis Model Assessment of Insulin Resistance and Insulin Secretion Capacity in a Comprehensive Health Checkup

Abstract

Aim: The association between aging and insulin resistance has been unclear. We evaluated the effects of aging on visceral fat area (VFA) and subcutaneous fat area (SFA) measured by computed tomography, homeostasis model assessment of insulin resistance (HOMA-IR), and homeostasis model assessment of β-cell function (HOMA-β) among participants in a comprehensive health checkup.
Methods: This study included 1,050 male and 700 female Japanese participants aged 35-84 years in our comprehensive health checkup program during a 2-year period. Participants who were on medication for diabetes mellitus or those who met the pre-determined exclusion criteria were excluded. The participants were divided into five groups according to age.
Results: As age increased from Group 1 to Group 5, both VFA and VFA/SFA ratio significantly increased in both male and female participants, whereas log[HOMA-IR] linearly and significantly decreased (p＜0.0001 for each). Body mass index (BMI), waist circumference (WC), and SFA increased with age in female participants but decreased in male participants. Although age was not or only weakly correlated with log[glucose] and log[HbA1c] in both male and female participants, age showed significant negative correlations with log[insulin], log[HOMA-IR], and log[HOMA-β] even after adjusting for BMI and WC (p＜0.0001 for each). Serum high-molecular-weight adiponectin (HMW-ADPN) levels were measured in 114 male and 87 female participants, and log[HMW-ADPN] was negatively correlated with log[HOMA-IR] and positively correlated with age in both male and female participants.
Conclusions: In the present study, both male and female participants showed increases in VFA and VFA/SFA ratio and decreases in insulin, HOMA-IR, and HOMA-β with age.