Risk Factors for Osteoporosis

What is the “cause” of any particular case of osteoporosis?  This can be maddening, but there is no answer to that question.

Medical experts speak in terms of "risk factors" for osteoporosis (and indeed for many diseases.  If you have one of these risk factors, you are at a greater risk for osteoporosis, but there is no guarantee the disease will develop.  And the converse is also true: people with many risk factors will not necessarily see a substantial drop in bone density.

Risk factors can be divided into ones that you cannot control and ones that you have some influence on.

Factors you can't control

Age – the older you get, the more susceptible you are to osteoporosis, which is a progressive disease.  Your bone density declines before you more into the point of osteoporosis proper.

Sex – Women are more likely to get osteoporosis, although men can get it too.

Heredity – It runs in families.  People whose parents had it are more likely to develop osteoporosis.  Also, very thin people – actually people with small bones – are at increased risk.  Bone size is mostly inherited, although it can be affected by malnutrition as a child.

Health problems including hormone abnormalities Cushing's disease and hyperparathyroidism (too much parathyroid hormone) and trouble digesting food and absorbing nutrients (Crohn's disease, celiac disease) are risk factors, too.  Thyroid abnormalities leading to hyperthyroidism and hypothyroidism (too much and too little hormone) are risk factors.

Paralysis of limbs substantially increases the risk as those bones are not stressed.  Many wheelchair-bound people get osteoporosis in their femurs.  Think of this as an extreme case of a sedentary lifestyle – low activity and exercise puts one at risk.

Lifestyle and Behavioral Risk Factors

Alcohol, and even caffeine consumption increase the risk of osteoporosis.   The effect of caffeine is weak, but it has been documented.  Caffeine consumption increases the risk for osteoporosis, apparently by slowing the spread of osteoblast cells. Chinese researchers have hypothesized that is is actually the bone marrow-derived mesenchymal stem cells (BMSCs) - which are the predecessors to the osteoblasts - that are more sensitive to caffeine. Alcohol has some health benefits in moderation, but it also has systemic effects and increases rates of many diseases.

Smoking is well known to be a major health hazard, increasing the risk of not only lung cancer, but of many diseases and conditions.  Smoking leads to problems throughout the body – both short-term and long-term.  The hazards of smoking are so well publicized and repeated that it can be easy to tune them out or forget that smoking affects more than just the lungs.

Smoking stunts the growth of new bone cells.  Researchers have determined that tobacco smoke increases not only your risk of osteoporosis, but that the risk rises the longer you keep smoking.  In other words, if you stop smoking, you slow your increase in risk.Actually, the observed connection is between smoking and low bone
density.  The connection to bone fracture risk is weaker.

Low back pain is more common among smokers.  While the proximate cause of the pain can come from many sources, one possibility is that the lumbar disks do not get enough oxygen and develop disease.  After surgery for broken hips, those who smoke heal more slowly than those who do not.

Women who smoke produce less estrogen and tend to start menopause earlier.  These increase the risk of osteoporosis.  There is also evidence that dietary calcium is not as well absorbed by smokers. A pack-a-day habit results in a 5 to 10 percent reduction in bone density by menopause.

Eating disorders like bulimia and anorexia increase the risk just by reducing the amount of nutrients entering the bloodstream.

Diet is a minor risk factor, possibly.  The effects of diet on otherwise healthy people as to their risk of developing osteoporosis is not clear.  Really low calcium intake over a period of years seems to play a part.  Deficiency in the childhood and adolescent years are particularly damaging and can result in osteoporosis in later life. Some people claim that an Atkins or Paleo type diet increases the risk of osteoporosis, but the evidence here is scant.

Being a couch-potato is a risk factor.  If you don't get much physical exercise, your chances of getting brittle bones increases.  Indeed, exercise is recommended as a way to prevent osteoporosis, or at least to reduce your odds of getting it. However, obese people are at lower risk for osteoporosis than skinny people are.

Very rapid weight loss can actually put one at risk.  The problem is that the decrease is not all fat or fat tissue.  Muscle is lost, and some bone is lost, too. Anorexics also tend to have high rates of osteoporosis.

Certain medicines cause bone loss as a side effect and their use can increase the risk of osteoporosis.  The corticosteroid medications – widely used for inflammatory conditions – can lead to bone loss if they are used for long periods of time.  Proton pump inhibitors for heartburn (acid reflux) and aromatase inhibitors for cancer also have bone loss listed as side effects.

UpToDate.com has a good page on risk factors at http://www.uptodate.com/contents/patient-information-osteoporosis-prevention-and-treatment

And the government (National Institutes of Health) has a good video on osteoporosis risk factors here: http://nihseniorhealth.gov/osteoporosis/riskfactors/video/osteo2_na_intro.html

Last updated: Mar 28, 2012