Relationship between physical activity and circulating fibroblast growth factor 21 in middle-aged and older adults

Objective: Circulating levels of fibroblast growth factor 21 (FGF21) increase with advancing age and may lead to the development of cardiometabolic diseases via impaired lipid and glucose metabolism. While physical activity can reduce these risks of cardiometabolic dysfunction, it remains obscure whether circulation FGF21 levels are influenced by physical activity. The purpose of this study was to investigate the relations between daily physical activities and circulating FGF21 levels in middle-aged and older adults. Methods: In this cross-sectional study with 110 middle-aged and 102 older adults, circulating (serum) FGF21 levels were evaluated by enzyme-linked immunosorbent assay, and the time spent in light-intensity physical activity (LPA) and moderate-to-vigorous-intensity physical activity (MVPA) was assessed using a uniaxial accelerometer. Results: Serum FGF21 levels in the older group (158 pg/mL) were significantly higher than those in the middle-aged group (117 pg/mL). When we examined the joint association of age (middle-aged or older) and MVPA (lower or higher than the median) groups, serum FGF21 levels in the older and higher MVPA group (116 pg/mL) were significantly lower than those in the older and lower MVPA group (176 pg/mL). However, there was no difference in serum FGF21 levels between the lower and higher MVPA groups in the middle-aged group. In multivariable liner regression analysis, serum FGF21 levels were independently determined by MVPA time after adjusting for potential covariates in older adults (β = −0.209). Conclusions: These cross-sectional study findings indicate that the time spent in MVPA is an independent determinant of circulating FGF21 levels, and that an age-related increase in serum FGF21 levels may be attenuated by habitually performing MVPA. (250/250 words).