Objectives
To assess whether childhood cardiorespiratory fitness (CRF) and muscular fitness phenotypes (strength, power, endurance) predict adult glucose homeostasis measures.
Design
Prospective longitudinal study.
Methods
Study examining participants who had physical fitness measured in childhood (aged 7–15 years) and who attended follow-up clinics approximately 20 years later and provided a fasting blood sample which was tested for glucose and insulin. Physical fitness measurements included muscular strength (right and left grip, shoulder flexion, shoulder and leg extension), power (standing long jump distance) and endurance (number of push-ups in 30 s), and CRF (1.6 km run duration). In adulthood, fasting glucose and insulin levels were used to derive glucose homeostasis measures of insulin resistance (HOMA2-IR) and beta cell function (HOMA2-β).
Results
A standard deviation increase in childhood CRF or muscular strength (males) was associated with fasting glucose (CRF: β = −0.06 mmol/L), fasting insulin (CRF: β = −0.73 mU/L; strength: β = −0.40 mU/L), HOMA2-IR (CRF: β = −0.06; strength: β = −0.05) and HOMA2-β (CRF: β = −3.06%; strength: β = −2.62%) in adulthood, independent of the alternative fitness phenotype (all p < 0.01). Adjustment for childhood waist circumference reduced the effect by 17–35% for CRF and 0–15% for muscular strength (males) and statistical significance remained for all associations expect between CRF, fasting glucose and HOMA2-β (p > 0.06).
Conclusions
CRF and muscular fitness in childhood were inversely associated with measures of fasting insulin, insulin resistance and beta cell function in adulthood. Childhood CRF and muscular fitness could both be potential independent targets for strategies to help reduce the development of adverse glucose homeostasis.