May Young Elite Cyclists Have Less Efficient Bone Metabolism?

Abstract

The purpose of this work was to describe changes in metabolic activity in the bones of young male competitive cyclists (CYC) as compared with age-matched controls (CON) over a one-year period of study. Eight adolescent male cyclists aged between fourteen and twenty, and eight age-matched controls participated in this longitudinal study. Serum osteocalcin (OC), amino-terminal propeptide of type I procollagen (PINP), beta-isomerized C-telopeptides (β-CTx) and plasma 25 hydroxyvitamin D [25(OH)D], were investigated by an electrogenerated chemiluminescence immunoassay. Analysis of variance revealed no significant differences in formation and resorption markers between cyclists and controls. Within the groups, both CYC and CON showed decreased OC at −30% and −24%, respectively, and PINP where the figures were −28% and −30% respectively (all p < 0.05). However, only the CYC group showed a decrease in [25(OH)D], lower by 11% (p < 0.05). The similarity in the concentrations of markers in cyclists and controls seems to indicate that cycling does not modify the process of bone remodeling. The decrease in vitamin D in cyclists might be detrimental to their future bone health.

The Role of Oxidative Stress in Multiple Exercise-Regulated Bone Homeostasis

“…Although a large number of studies have confirmed the lack of positive effects of these endurance activities on BMD and BMC levels in adolescents, there is not much direct and strong evidence regarding the related BTM indicators. The research results of Rapun-Lopez et al [ 56 ] showed that, with increasing age, OCN and PINP concentrations decreased in both the cycling group and the control group, while β-CTX concentrations showed no significant difference. However, it should be pointed out that, during this period, the vitamin D level of the cyclists decreased significantly.…”

Calcium, Vitamin D, and Health

“…Two other studies investigated the links between 25(OH)D and bone outcomes in young populations. Gil-Cosano et al [4] revealed a mediating effect of muscular fitness on the relationship between 25(OH)D levels and BMD in children who were overweight/obese, while Rapun-Lopez et al [5] showed similar bone remodeling in adolescent male cyclists than age-matched active controls over one year, but lower 25(OH)D. In adult and older women from the Chilean National Health Survey 2016-2017 (total N = 1931), Solis-Urra et al [6] found a joint association of high sedentary time/passive commuting to be associated with 25(OH)D deficiency, even after controlling for sun exposure. This finding connects with the studies mentioned above [1][2][3] due to the proposed link between sedentary time and increased adiposity, as well as between adiposity and reduced 25(OH)D levels.…”