An Analysis of Age-Related Body Composition Changes and Metabolic Patterns in Korean Adults Using FDG-PET/CT Health Screening Data

Abstract

Backgruound: F-18-fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) can be used to measure bone mineral density (BMD), cross-sectional muscle area (CSMA), Hounsfield units (HU) of liver and muscle, subcutaneous adipose tissue (SAT), abdominal visceral adipose tissue (VAT), and glucose metabolism. The present study aimed to identify age-related changes in body composition and glucose metabolism in Korean using opportunistic FDG-PET/CT imaging.

Methods: We analyzed FDG-PET/CT, clinical history, and laboratory data abstracted from the medical records of patients who underwent health screening at a single institute between 2017 and 2022.

Results: In total, 278 patients were included in the analysis (male:female=140:138). Age and body mass index were positively correlated in female, but negatively correlated in male. BMD decreased with age more in female, and CSMA decreased with age more in male. Muscle HU decreased with age for both sexes. In female, SAT and VAT increased with age; and in male, SAT decreased slightly while VAT remained stable. Muscle glucose metabolism showed no association with age in male but increased with age in female. CSMA correlated positively with BMD overall; and positively correlated with VAT and SAT in male only. In female only, both SAT and VAT showed negative correlations with glucose metabolism and correlated positively with muscle glucose metabolism. Liver HU values were inversely correlated with VAT, especially in female; and positively correlated with muscle glucose metabolism in female only.

Conclusion: FDG-PET/CT demonstrated distinct patterns of age-related changes in body composition and glucose metabolism, with significant differences between sexes.

Keywords: Aging; Body composition; Positron emission tomography computed tomography.

Fig. 1.

Measurement of body composition parameters. (A) Abdominal visceral adipose tissue and (B) abdominal subcutaneous adipose tissue show in an axial image using the transverse process of the fourth lumbar vertebra. (C) Cross-sectional muscle area and (D) circular region-of-interest with a 1 cm diameter within the psoas muscle (white arrow) shown in an axial image using the transverse processes of the third lumbar vertebra.

Fig. 2.

Age-related in body composition changes by sex. Age-related changes analyzed by (A) body mass index (BMI), (B) Hounsfield unit (HU) values for bone mineral density (BMD), (C) cross-sectional muscle area (CSMA), (D) muscle HU values, amounts of (E) abdominal visceral adipose tissue (VAT), and (F) abdominal subcutaneous adipose tissue (SAT).

Fig. 3.

Correlations among body composition parameters. Correlations of cross-sectional muscle area (CSMA) with Hounsfield unit (HU) values of muscle (A) and bone mineral density (BMD) (B). Correlation of glucose metabolism, measured as the maximum correlation of glucose metabolism, measured as the maximum standardized uptake value (SUV_max), with the amount of (C) abdominal visceral adiposes tissue (VAT), and (D) abdominal subcutaneous adiposes tissue (SAT).

Fig. 4.

Correlations between fat-related parameters and muscle-related parameters. Correlations of muscle glucose metabolism, measured as the maximum standardized uptake value (SUV_max), with (A) visceral adiposes tissue (VAT) and (B) abdominal subcutaneous adiposes tissue (SAT) in female. Correlation of cross-sectional muscle area (CSMA) with (C) VAT and (D) abdominal SAT in male.

Fig. 5.

Correlations among body composition parameters. Correlations among body composition parameters in (A) male and (B) female presented as a heat map. BMI, body mass index; BST, blood sugar test; CSMA, cross-sectional muscle area; HU_M, Hounsfield unit (HU) of muscle; VAT, amounts of visceral adipose tissue; VAT_met, maximum standardized uptake value (SUV_max) of visceral adipose tissue; SAT, amounts of subcutaneous adipose tissue; SAT_met, SUV_max of subcutaneous adipose tissue; BMD, bone mineral density; Muscle_met, SUV_max of muscle.