Publication date: Jan 2019
What is already known about this subject:
- The attainment of maximal peak bone mass is a strong predictor of reduced fracture risk in later life, and both age and the degree of skeletal maturity are crucial factors in optimising how bone will adapt to the loads applied to it.
- There is a critical need for longitudinal cohort studies to consider the cumulative exposure of physical activity and bone mass.
- The aim of this study was to investigate the relationship between organised sports trajectories (that capture distinct and potentially meaningful patterns over critical developmental periods) and peak bone mass.
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What this study adds
- Participation in organized sport was recorded by parental/self-report at ages 5, 8, 10, 14, 17 and 20 in 984 offspring (48% female) of a pregnancy cohort (Raine Study). Latent class analysis identified three trajectory classes in each sex. In females, these were consistent sport participators (53%), dropouts (32%), and nonparticipators (15%); in males, consistent sport participators (58%), dropouts (35%), and sport joiners (7%). Whole body bone mineral content (BMC) at age 20 was assessed by dual-energy X-ray absorptiometry (DXA).
- After adjustment for height, body mass, physical activity, calcium intake, serum 25-hydroxyvitamin D, alcohol, and smoking (all at age 20 years), females in the consistent sport participator trajectory had significantly greater leg BMC (570 ± 2g) than dropouts (458 ± 3g) and non-participators (457 ± 4g) (all p<0.05). In males, consistent participators had significantly greater whole body (3251 ± 14g vs 3092 ± 18g), leg (597 ± 3 vs 559 ± 4g) and arm BMC (222 ± 1.2 vs 214 ± 2g) than dropouts (all p<0.05), whereas sports joiners had significantly greater leg (594 ± 8 vs 559 ± 4g) and arm BMC (220 ± 3 vs 214 ± 2g) than drop outs (all p<0.05).
- Participation in organized sport during childhood and adolescence predicts bone mass at age 20. Since attainment of optimal peak bone mass is protective against osteoporosis in later life, this may have long term skeletal benefits.