Physical activity performed at an early age results in sustained improvement in bone health evidenced by higher bone mineral content (BMC). Early childhood may be an important developmental period for promoting physical activity to optimize peak bone mass during young adulthood and prevent osteoporosis during later years.
Janz and colleagues studied 333 participants in the Iowa Bone Development Study. They looked at how physical activity at age 5 years affects bone density at 8 and 11 years, after correcting for height, weight, age, maturity, and activity.
The children who were most active at 5 years had the highest BMC at 8 and 11 years. The most active children had 4% to 14% higher BMC levels than the least active ones. For boys, the BMC increase at the whole body, spine, and hip was 8%, 14%, and 11%, respectively, by 8 years and 5%, 7%, and 7%, respectively, by 11 years. For girls, the BMC increases were 6%, 8%, and 8% by 8 years and 4%, 6%, and 5% by 11 years.
The authors noted that less active young children may miss the opportunity to obtain the highest peak BMC later in life, when they are likely to be less active.