- A woman develops about half her bone mineral content during her adolescent years, and healthy bone mineral content and bone mass lower the risk for stress fractures
- If a young woman has poor bone mass as an adolescent, one study has shown that there�??s nearly a 90% chance that she�??ll continue to have low bone mass 3 years later
- That study along with many others clearly point out that it is very difficult to regain bone mass once it�??s lost and a strategy to maintain healthy bone mass from the start is critically important
I think I jinxed myself last week when I wrote about stress fractures in the foot because 
this week I saw two more young female runners with stress fractures, this time in the hip. With so many young women playing sports (which is definitely a good thing!) I thought it was worth looking at the topic of bone loss in young female athletes a bit deeper. The specific question this week: if a young female has issues with low bone mass or bone density can she regain it later on?
It�??s been shown that a woman develops about half of her bone mineral content during her adolescent years. In these formative years, factors such as decreased or absent menstrual cycles, lower body mass index, decreased calorie intake, and participation in endurance running sports can negatively affect bone content. An important question then becomes whether these young female athletes regain that lost bone later on in life.
One of the better studies I�??ve seen on this subject was published in 2011 by Barrack and colleagues. Unfortunately the study results were not encouraging. The researchers analyzed 40 female runners with an average age about 16 years. They then administered a survey three years later to evaluate menstrual status and sports training and performed DEXA scans to assess bone mineral density.
Here�??s the really unfortunate part: 87% of the female runners with low bone mineral density at the first test still met the criteria for low bone mass three years later. Compared to females with normal bone mass levels, those with decreased bone mass tended to run more total miles and more miles in the off season. Almost half had menstrual irregularity or took oral contraceptives for menstrual irregularity. What was harder for the authors to determine was whether the bone loss was irreversible or whether those females engaged in activities, such as increased running, or had factors, such as menstrual irregularities, that prevented them from regaining bone mass.
This study and others point out how important it is for a young female athlete to take
bone health seriously. If you�??re a young woman runner with lingering bone pain please get it evaluated properly. If you�??re not having regular menstrual cycles, you should discuss that issue with your OB-GYN or family doctor. If you�??re having nutritional issues with calorie intake or food quality, please consult a nutritionist early on and take corrective steps.
The Barrack study shows that once bone loss occurs in adolescent runners, it is unlikely to significantly improve. Almost 9 out of 10 young female runners in this study continued to have low bone mass three years later. It�??s far better to develop and keep healthy bone mass early on rather than to fight to make it up once it�??s lost.
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