Increased High-Intensity Activity Early in Life Could Decrease Osteoporosis Risk

Ahmed Elhakeem, PhD

A new assessment of data from patients within the Avon Longitudinal Study of Parents and Children suggest increased physical activity in adolescence could pay dividends in the form of reduced risk for osteoporosis later in life.

Using accelerometer data from the study, investigators determined increased high-intensity physical activity between the ages of 12-16 years old could help maximize peak hip strength at 25 years old and prevent osteoporosis in later life.

In an effort to identify potential modifiable life factors associated with attainment of peak hip strength in adulthood, investigators from the University of Bristol designed an analysis of more than 2500 offspring from the Avon Longitudinal Study of Parents and Children. A prospective birth cohort study of 15,545 pregnant women and 15,589 infants, the study included a group of 2569 healthy offspring with up to 4 accelerometer assessments and physical activity measurements from a clinical assessment occurring at 12, 14, 16, and/or 25 years.

Using femur neck bone mineral density at 25 years as the primary outcome measure, investigators hoped to determine how time spent in moderate to vigorous-intensity and light-intensity physical activity earlier in life impacted peak hip strength in adulthood.

For inclusion in the current analysis, patients needed at least 3 or more days of valid data from their accelerometer, which investigators defined as 500 minutes or more per day after the exclusion of intervals of 60 minutes or more of 0 counts. Of note, activity county per minute thresholds were used to calculate time spent in moderate to vigorous–intensity and light-intensity physical activity throughout adolescence.

Of the 2569 patients included in the study, 1588 were females and 981 were men. In comparison to their female counterparts, male patients spent more time in moderate to vigorous-intensity activity at each of the ages examined and had greater adult femur neck bone mineral density.

From their initial analysis, investigators created 3 moderate to vigorous activity subgroups and 3 light-intensity subgroups for each sex. For moderate to vigorous-intensity trajectories in males, 85% of participants were in the low adolescent subgroup, 6% were in the high early-adolescent subgroup, and 9% were in the high mid-adolescent subgroup. For moderate to vigorous-intensity trajectories in females, 73% of participants were in the low adolescent-low adult subgroup, 8% were in the low adolescent-high adult subgroup, and 19% were in the high adolescent subgroup. Investigators classified light-intensity physical activity trajectories into subgroups defined as low nonlinear, moderate decreasing, and high decreasing for both sexes.

Among male patients, femur bone mineral density was greater among patients in the high early-adolescent subgroup (0.38 g/cm²; 95% CI, 0.11-0.66 g/cm²) and the high mid-adolescent subgroup (0.33 g/cm²; 95% CI, 0.07-0.60 g/cm²) when compared against the low adolescent subgroup. Among female patients, femur neck bone mineral density was greater among patients in the high adolescent group (0.28 g/cm²; 95% CI, 0.15-0.41 g/cm₂), but not among those in the low adolescent-high adult subgroup (−0.12 g/cm²; 95% CI, −0.44 to 0.20 g/cm²) when compared against patients in the low adolescent-low adult subgroup. Investigators pointed out light-intensity trajectories were not associated with femur neck bone mineral density.

"The unique availability of repeated accelerometer assessments over many years beginning at age 12 within the Children of the 90s cohort, allowed us to describe the trajectory of time spent in different physical activity intensities through early life and to examine how this might relate to adult hip strength,” said Ahmed Elhakeem, PhD, MPH, lead investigator and Senior Research Associate in Epidemiology at the University of Bristol, in a statement. “The results highlight adolescence as a potentially important period for bone development through high intensity exercise, which could benefit future bone health and prevent osteoporosis in later life.”

This study, “Physical Activity Throughout Adolescence and Peak Hip Strength in Young Adults,” was published in JAMA Network Open.