Bobby Clay, Lauren Howarth, Anna Boniface – isolated cases in elite performers or the tip of the iceberg? Conversation in recent months suggest perhaps the latter. Personally, I see one athlete with low bone mineral density (BMD) as one too many. I know the implications far too well.
Six years ago I was diagnosed with osteopenia, low BMD, the precursor to osteoporosis. A diagnosis of low BMD doesn’t make me feel physically different but it does come with a lifetime warning label. I’ve developed an instinctive risk analysis that activates every time there’s a change in training load or when someone asks about going ice-skating or mountain biking or innumerable other excursions. These activities come with risks to all, with low BMD the risk is higher. Diagnosis at 19 years brings the added challenge of sitting in waiting rooms, filled with people 40+ years your senior. Each visit tolerated in hope of a solution. But how do you treat a 19-year-old with an ageing disease? They may say osteoporosis is a silent disease, but it certainly has loud consequences.
For me the damage is done. Years of low energy and low estrogen status have taken their toll. For those less familiar these are components of the female athlete triad and relative energy deficiency in sport (RED-S). My BMD has improved over the past few years, but it will never reach the potential it could have. I will live at increased risk of fracture for the rest of my life.
While regret is a waste of energy, reflection is critical for improvement. In ways I was fortunate, given the opportunity to partake in a study led to the initial warning, allowing me to pursue medical guidance and receive clinical diagnosis. I was young, still building bone. I had a chance to address the cause. As a Sport and Exercise Science student beginning my journey in research I had opportunities to ask questions, to read, to search for an answer. It was these experiences that led to my current quest: to evaluate how big this problem is and to contribute to a solution.
Initially, we launched a survey to assess the prevalence of injuries and previous BMD assessments (if you’ve already completed thanks! If you are a female distance runner perhaps you’re interested in participating and helping us understand more). Within the research facilities of the UL Body Composition Study we also have access to BMD assessment by dual energy x-ray absorptiometry (DXA). However, BMD has limitations. It takes time for measureable changes to occur. The warning signs of poor bone health have usually been there for much longer. The effects of low energy availability and menstrual dysfunction might not be immediately noticeable but left untreated these risk factors will take their toll.
Briefly, here’s how…
Optimal energy availability (calculated by assessing energy intake – exercise energy expenditure relative to fat free mass) means that there is adequate intake to meet the demands of training, recovery, and support many physiological systems including bone health, menstrual and immune function. With insufficient energy to fuel all these systems the human body adapts. But these energy conservation measures come at a cost to key systems including the endocrine (hormone) and skeletal systems. Low energy leads to downregulation of the normal pathways that support bone health resulting in less bone formation. Concurrently, menstrual function is compromised through the hypothalamic-pituitary-ovarian axis.
There is a shift from eumenorrhea, normal menstrual function (menarche by age 15 and regular 24-35 day cycles), to disturbances. Initially these might be subclinical and difficult to detect. They may progress to oligomenorrhea (36-90 day cycles) or amenorrhea (absence of menses for >90 days) both classified as severe menstrual disturbances. Each of these scenarios results in a low estrogen environment – bad news for bone health. Without estrogen bone resorption is promoted. Low energy and menstrual dysfunction together (as is often the case) amplifies the negative effects. Add in low body fat, typical of athletic populations (itself associated with menstrual dysfunction and poor bone health) and there is a ‘perfect storm’.
This ‘perfect storm’ is the biggest dilemma I believe we as scientists/ health practitioners/ coaches/ athletes face today. Under the surface the damage is being done. But by the time a clinical condition (e.g. low BMD) is evident someone is already at increased fracture risk.
And so I questioned – can we use a more sensitive measure? Something that detects changes earlier or helps us evaluate if an intervention is helping? Biomarkers of bone turnover are measured in blood and urine. They are an indicator of how much bone resorption and formation (the processes that underpin changes in BMD) are occurring. Is it normal? Is it aberrant? Is it balanced? These biomarkers are sensitive to acute nutrient, activity or hormonal changes, providing an ecologically valid measure of bone health in athletes. However, before we can widely use these markers to monitor athlete health we need greater understanding. This is the aim of a study we are currently recruiting for. Simultaneously we assess (and give feedback on) dietary, exercise and body composition parameters which are known to affect bone (if you are interested please feel free to contact me to learn more).
As a scientist I thrive in objectivity. But it is personal experience that instils such deep meaning in what I do. It is what helps me persist when faced with challenges. It is what encourages me to keep asking why, what can we do better? It is what makes participating in pilot work an opportunity rather than a chore. I know how frustrating it is to have to wait months to see if anything I’m doing is helping. As a researcher and sport scientist I have an ambition to change this. Personally, injury has been heart-breaking, professionally it has been an incredible source of motivation. If I get to understand more about myself along the way to supporting the health and performance of others perhaps that is the ultimate reward.
Jennifer Higgins is a postgraduate researcher in the department of Physical Education and Sport Sciences at the University of Limerick. Her current research interests include the role of nutrition and physical activity on bone health in female endurance athletes. Contact Jennifer via email at jennifer.higgins@ul.ie or follow Jennifer or Twitter
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