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Why do I have Osteoporosis? I’m Way too Young!

Question

I slipped on some soggy leaves while walking home from work. I ended up breaking my upper arm. I'm only 36-this kind of fracture typically happens in 80 year olds! My bone density shows a Z-score of -3, meaning I have osteoporosis by bone density as well as low trauma fracture. But how I could have osteoporosis since I am so young and do everything right? I walk about an hour a day (my commute), I eat yogurt and cheese and drink 3 glasses of skim milk a day-all my life I have taken a multi vitamin. My weight is perfect. I've never skipped a period and they come predictably every 27 days. I don't even have osteoporosis in my family. Why did I break my arm???

Answer

I'm very sorry about your fracture. The good news is that, given your healthy life, your fracture will likely heal rapidly. Also, I believe that you (working with your family doctor) can prevent further bone loss and subsequent fractures. But first I will try to answer your question.

Why do young women break bones?
Despite enough calcium, vitamin D, good exercise and normal estrogen levels (as indicated by regular menstruation), young women do occasionally fracture. Sometimes it is because of obviously abnormal nutrition (anorexia, weight cycling, being underweight). Other times it is because of obviously abnormal reproduction, such as a first period when older than age 16, or amenorrhea (the period stopping and low estrogen and progesterone levels). Osteoporosis can also occur because of alcohol, cigarette or drug abuse plus the unhealthy lifestyles that often go with those addictions. But it sounds like you have none of those problems.

How can a regularly menstruating, normal weight woman lose bone?
That was totally mysterious until recently. We at CeMCOR recently presented a meta-analysis combining the data from all the scientific articles that reported on the rate of bone change in menstruating women and also tracked women's ovulation. There are now five published studies (1-add reference to J. Osteoporosis 2010). Although these reports used different ways to document ovulation (release of an egg), as described in an earlier CeMCOR newsletter (link), quantitative basal temperature (QBT) was the most common. This simple-to-do method also provides the luteal phase length, meaning the number of days in the cycle during which progesterone is high-normal, by QBT, is 10-16 days. Women with the most disturbed ovulation despite regular menstruation-either frequent anovulatory or short luteal phase length cycles-lose about one percent of spinal bone density a year while those with less frequent or no ovulatory disturbances gain bone.

Why are ovulatory disturbances related to bone loss?
During the normal menstrual cycle, estrogen rises from a low level during flow to a mid-cycle peak just before ovulation. Estrogen's "job" in bones is to stop bone loss. But the other side of the coin is that, as estrogen levels decrease, bone loss is stimulated. And estrogen levels decrease from the middle of the cycle until the next mid-cycle peak. Therefore, to prevent bone loss, we need progesterone to do its "job" which is to stimulate the building of new bone. Therefore, unless ovulation occurs normally there will be some bone loss in young women.

Why would a healthy, regularly menstruating woman not ovulate?
Surprising as it may seem-worry or stress or illness-are sufficient to disturb ovulation. I'll explain the bone-worry and bone-ovulatory disturbance connections in turn.

All of us experience some worry or stress-I like to think of these as being a "threat" to our well being. The hypothalamus in the centre of the brain has the job of assessing the level of threat by integrating signals about nutrition related to bodily needs and activity, emotions and environmental factors. If we are under increased threat (whether from too few calories for what we burn, illness or a stressor like the death of a loved one or sexual abuse) the response is an increase in hypothalamic stress hormones (such as corticotrophin releasing hormone [CRH]) that triggers the pituitary to release its stress-stimulating hormone [ACTH]. ACTH causes the adrenal gland to make more stress hormones like Cortisol and DHEAS. Cortisol, although it is absolutely necessary for our whole-body response to threat, has very negative bone effects in high doses or prolonged durations-it increases bone loss and paralyzes bone formation. (Medicines similar to cortisol, like Prednisone, are very negative for bone and cause fractures.)

A second stress response system involves the catecholamines (hormones that are part of the ‘fight or flight' response) that are made in the adrenals and by nerve endings (epinephrine and norepinephrine). These also are likely negative for bone (although we know less about how they relate to bone metabolism).

Thus, the first way threats relate to bone is through stimulating bone-negative stress hormones. The second way is by suppressing reproduction. Silent ovulatory disturbances within regular cycles are likely the most common end result of stress for women. Ovulatory disturbances within regular cycles probably occur in about a third of all menstrual cycles (1).

What kinds of worry are associated with bone loss?
Every imaginable worry is associated with bone loss-from exam stress, to a flu, to compulsive over-exercise. Even a worry like carefully considering every food to assess whether it might make us gain weight (called Eating Restraint), is a strong enough "stressor" to be associated with higher cortisol levels (2). In a study of 66 women who were healthy, non-smokers with normal weights and varying exercise habits we found that those who had more ovulatory disturbances lost bone (3). In fact, in that study, 20% of the change in bone was accounted for by the average luteal phase length of every cycle during one year (3). We later showed that eating restraint was associated with ovulatory disturbances (4). More recently two 2-year long studies in over 100 menstruating women each showed that those with more eating restraint had more frequent ovulatory disturbances and increased bone loss (5,6).

With all that as a background,

Here are some suggestions to help you regain bone and prevent fractures:
1. Are you quite concerned about becoming overweight? So much concerned that you would carefully consider each food before eating it? If you are, then you may have eating restraint. Because eating restraint is associated with feeling insecure and stressed, I'd suggest you make a
conscious effort to focus on positives about food (their good nutrients and that they can be comforting) rather than their threats of overweight. Take a positive look at food-see fruits, vegetables, grains, protein and unsaturated fats and all healthy foods as providing the nutrients you need to build strong bones. Please, also, learn and start regularly doing something-like relaxation, yoga breathing or meditation-that will decrease your stress hormone responses to perceived threats.

2. You said your weight is perfect. However, within the normal range of 18.5-24.9 body mass index (BMI = weight in kilograms divided by the height in meters squared), values lower than 20 may not be perfect for bone or for your muscle mass and build. I'd suggest that you allow yourself to gain to a BMI of at least 20 if you are skinnier than that. One strategy that helps is if you eat a handful of almonds or other nuts between meals and at bedtime. Please work on building muscle (by weights or other exercise) if your BMI is over 20 but still within the optimal range.

3. Next question is-are you ovulating normally? You can start to learn about your menstrual cycle by keeping the Menstrual Cycle Diary.
Over time you will learn more about yourself, including things that vary across cycles and how they relate to your feelings and sense of stress. You can view video clips about keeping the Diary by linking to them on YouTube.

By taking your first morning temperature (that you can record at the bottom of the Diary) you can find out about whether you have ovulated and if yes, what your luteal phase length is in each cycle. To learn how, read the instructions here. To tell if you've ovulated and have a normal number of days of progesterone production requires a simple calculation of your average temperature in a given cycle.

Even though this QBT method is simple, takes less than 2 minutes a day and is inexpensive (the cost of a digital thermometer), it has been well validated against hormone levels and shown to be accurate (7,8).

4. If you are having anovulatory or short luteal phase cycles even if they occur only every third cycle, you are at risk for further bone loss. Based on a previous randomized placebo-controlled trial we did with cyclic medroxyprogesterone (a synthetic cousin of progesterone)(9), cyclic oral micronized progesterone (Prometrium®)[see Progesterone Therapy] 300 mg at bedtime cycle days 14-27 will cause you to gain about 2% in spinal bone density a year.

5. Summarizing everything that will help you gain bone and strength and prevent further fractures, follow the suggestions in the ABCs of Premenopausal Osteoporosis Prevention including:
a. Continue your regular exercise
b. Increase muscle and maintain and optimum weight of BMI 20-27.
c. Continue to drink your three glasses of skim milk a day but add to that a 500 mg calcium supplement or an extra calcium food at bedtime (to slow the bone loss that increases overnight).
d. Increase your vitamin D by adding 1000 IU/day to your daily multi vitamin.
e. Commit yourself to practice the stress-reduction strategies I suggested earlier.
f. Take cyclic progesterone treatment (that your doctor can prescribe) if you are not consistently ovulating.
g. Continue your excellent habits-I assume you don't smoke, that you limit alcohol to one drink a day and avoid colas or more than 3 caffeinated drinks a day.

Hope this is helpful for you,
All the best,
Jerilynn

 

References

  1. Seifert-Klauss V, Prior JC.. Progesterone and bone: actions promoting bone health in women. J Osteoporos. 2010 Oct 31;2010:845180.
  2. McLean JA, Barr SI, Prior JC. Cognitive dietary restraint is associated with higher urinary cortisol excretion in healthy premenopausal women. Am.J.Clin.Nutr. 2001;73:7-12.
  3. Prior JC, Vigna YM, Schechter MT, Burgess AE. Spinal bone loss and ovulatory disturbances. N Engl J Med 1990;323:1221-7.
  4. Barr SI, Prior JC, Vigna Y. Restrained eating and ovulatory disturbances: Possible implications for bone health. Am J Clin Nutr 1994; 59: 92-7.
  5. Waugh EJ, Polivy J, Ridout R, Hawker GA. A prospective investigation of the relations among cognitive dietary restraint, subclinical ovulatory disturbances, physical activity, and bone mass in healthy young women. Am.J Clin.Nutr. 2007;86(6):1791-801.
  6. Bedford, J. L., Prior, J. C., Barr, S. I., and . A prospective exploration of cognitive dietary restraint, subclinical ovulatory disturbances, cortisol and change in bone density over two years in healthy young women. JCEM . 2010.
  7. Bedford JL, Prior JC, Hitchcock CL, Barr SI. Detecting evidence of luteal activity by least-squares quantitative basal temperature analysis against urinary progesterone metabolites and the effect of wake-time variability. Eur.J Obstet Gynecol Reprod Biol. 2009;146(1):76-80.
  8. Prior JC, Vigna YM, Schulzer M, Hall JE, Bonen A. Determination of luteal phase length by quantitative basal temperature methods: validation against the midcycle LH peak. Clin.Invest.Med. 1990;13:123-31.
  9. Prior JC, Vigna YM, Barr SI, Rexworthy C, Lentle BC. Cyclic medroxyprogesterone treatment increases bone density: a controlled trial in active women with menstrual cycle disturbances. Am.J.Med. 1994;96:521-30.

 

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