One day when my daughter was in middle school, she wore a bathing suit under her clothes. Naturally, I wondered why! She told me she was being screened for scoliosis. She asked me if it was true, as a friend had told her, that bad posture could cause scoliosis or a permanent stoop. I have heard that one before and have even seen it on television shows: "Sit up straight, dear, or you'll end up hunched over like your Aunt Edna." Is it true that you can prevent trouble in your spine later by paying attention to your posture now? If so, what are the best ways? What can be done to prevent the stooped posture of so many people as they age?
Posture and Scoliosis
Scoliosis is a condition in which there is a curvature of spine to one side; in severe forms, the bones of the back form an S-curve when viewed from behind. The spine can also curve from front to back, a term called "kyphosis" (excessive backward curvature of the mid-section of the spine) or "lordosis" (excessive forward curvature of the lower back and neck portions of the spine). In fact, many people with osteoporosis have "kyphoscoliosis" which combines two of these terms to describe the simultaneous curvature from side to side and front to back.
The most common forms of scoliosis occur in young people, especially adolescent girls. Overall, it affects an estimated 2% to 3% of children under age 16, and in the vast majority of cases there is no identifiable cause. More rarely, it may be present at birth (infantile scoliosis, a potentially serious problem often associated with other birth defects) or develop during young adulthood. Minor amounts of curvature are common and often are medically unimportant. Screening programs in schools and examinations by pediatricians are intended to identify scoliosis early, when it's mild, in the hopes of preventing progression to more severe forms.
Mild scoliosis — which include approximately 90% of cases — usually requires no therapy, although it is important that any curvature be monitored over time for worsening. More severe curvature may be treated with braces, exercises (including ones to improve posture), or surgery. Many factors go into the choice of treatment: gender, age, maturity (for example, whether bone development is complete), severity of the curve, and its progression over time.
Many things about scoliosis are unclear. Why does it occur? Which people with scoliosis will get worse over time? When does treatment make a difference? Which treatments are best? One thing does seem clear: Sitting up straight in your chair or while walking will not prevent scoliosis. Improved posture may have other benefits, such as preventing muscular back pain or making your mother happy, but there is no evidence that consciously trying to improve your posture will have a long-term effect on the alignment or health of your spine.
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Posture and Osteoporosis
Osteoporosis is a condition of reduced bone thickness (or density). The reason it matters so much is that it increases the chances that a bone will fracture with an injury (most often, the wrist or hip) or even spontaneously (usually, the spine). These fractures may lead not only to loss of height and spine deformity — including scoliosis — but also may require major surgery. Osteoporotic fractures of the hip can lead to disability and death, so the disease is not just a matter of losing height or having spine problems.
When a bone in the spine fractures due to osteoporosis, it appears compressed or compacted on an X-ray. These "compression fractures" lead to the loss of height and curvature (often called a dowager's hump in elderly women) typical of people with significant osteoporosis. There are several possible causes, including inherited (genetic) factors, diet (inadequate calcium and/or vitamin D), lack of estrogen, certain medications, an overactive thyroid (or too much thyroid medication), alcohol or smoking. Aging itself is a risk factor for osteoporosis, but not every person of advanced age develops it, so these other factors are often important. However, missing from this list is posture: Poor posture does not lead to osteoporosis or the stooped-over posture of people with osteoporotic spinal fractures.
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Reasons for the Myth
This myth — that walking upright or sitting up straight will prevent curvature of the spine — probably developed because of the intuitive notion that voluntarily keeping the spine straight will prevent it from curving. It seems simple enough, however, there is no evidence that it is true. This misconception may be because the cause of a condition has been confused with the effect of that condition. The association of scoliosis with abnormal posture does not mean that poor posture (however one defines it) causes scoliosis. This is the sort of myth that will not die quickly: It has been around for generations and many are convinced it is true.
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Protecting Your Spine
There are ways to protect your spine from abnormal curvature. The most important are the preventative treatments for osteoporosis. We know from extensive research that higher bone mass achieved in early adulthood helps to prevent future osteoporosis. For this reason, lifelong attention to adequate calcium and vitamin D intake and weight-bearing exercise are good starting points. As a woman approaches menopause, loss of estrogen is associated with more rapid bone loss. Depending on risk factors, it may be helpful to have a test to measure bone density and to consider estrogen or other therapy to reduce bone loss and increase bone strength.
Screening programs may detect mild curvature in children or adolescents; however, X-rays are necessary to confirm the diagnosis. Many children who are told they may have scoliosis in a screening program have normal X-rays (and therefore do not have the condition). The more severe (and important) forms of scoliosis are more reliably detected by screening, while a mild amount can easily be missed. Of course, if you are concerned about your child's posture or your own, discuss it with your child's pediatrician or your own health care professional. He or she will want to find out about symptoms and perform an examination. These will be helpful to provide reassurance and to figure out whether X-rays or other investigation is warranted.
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The Bottom Line
If someone is nagging you about your posture, it may be best to try improving it. It may make your back feel better and keep harmony in the household, but don't be fooled into thinking you will prevent scoliosis or osteoporosis of the spine. If someone warns you about the dangers of "slouching," tell them they are confusing cause and effect, and remind them that Aunt Edna's posture may have been perfect in her younger days.
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Robert H. Shmerling, M.D., is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.