High impact physical activity and bone health of lower extremities in childhood cancer survivors: A cross‐sectional study of SURfit

Childhood cancer survivors (CCS) are at risk of reduced bone health and premature osteoporosis. As physical activity with high impact loading (IL‐PA) is known to promote bone health, we compared bone densitometry and microstructure between groups of CCS who performed different amounts of physical activities in their daily life. We used baseline data of a single‐center PA trial including 161 CCS from the Swiss Childhood Cancer Registry, aged 2 g acceleration and numbers of vertical impacts/hr >2 g) was captured using hip‐worn accelerometers (1–3 weeks). For both IL‐PA approaches, we formed low, middle and high activity groups based on tertiles. Bone health of the high and middle active groups was compared to the low active group. 63% of CCS had indication of at least one bone mineral density z‐score ≤ −1 measured by pQCT or DXA. The high IL‐PA group performing 2.8 min/day or 19.1 impact peaks/hr > 2 g (median) showed about 3–13% better microstructural and densitometric bone health as compared to the low IL‐PA group with 0.38 min/day or 0.85 peaks/hr > 2 g. Just a few minutes and repetitions of high IL‐PA as easily modifiable lifestyle factor may be sufficient to improve bone health in adult CCS. Future longitudinal research is needed to better understand pattern and dosage of minimal impact loading needed to strengthen bone in growing and adult CCS. What's new? Childhood cancer strikes during a critical period of physical development, often with consequences for bone health later in life. Although little is known about benefits in childhood cancer survivors (CCS), high‐impact loading physical activity (IL‐PA) is a promising means of improving bone strength. In this study of CCS at a Swiss pediatric oncology clinic, young patients were found to benefit from increased daily duration and frequency of IL‐PA. Even just several minutes and repetitions of impact loading per day yielded significant improvements in bone density, suggesting that IL‐PA is a simple and feasible measure of increasing bone strength in CCS.