How Common Is It?

At some point, back pain affects an estimated 8 out of 10 people. It is one of our society's most common medical problems.

What Are the Risk Factors for Back Pain?

Although anyone can have back pain, a number of factors increase your risk. They include:

Age: The first attack of low back pain typically occurs between the ages of 30 and 40. Back pain becomes more common with age.

Fitness level: Back pain is more common among people who are not physically fit. Weak back and abdominal muscles may not properly support the spine. "Weekend warriors" – people who go out and exercise a lot after being inactive all week – are more likely to suffer painful back injuries than people who make moderate physical activity a daily habit. Studies show that low-impact aerobic exercise is good for the discs that cushion the vertebrae, the individual bones that make up the spine.

Diet: A diet high in calories and fat, combined with an inactive lifestyle, can lead to obesity, which can put stress on the back.

Heredity: Some causes of back pain, including disc disease, may have a genetic component.
Race: Race can be a factor in back problems. African American women, for example, are two to three times more likely than white women to develop spondylolisthesis, a condition in which a vertebra of the lower spine – also called the lumbar spine – slips out of place.

The presence of other diseases: Many diseases can cause or contribute to back pain. These include various forms of arthritis, such as osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis, and cancers elsewhere in the body that may spread to the spine.

Occupational risk factors: Having a job that requires heavy lifting, pushing, or pulling, particularly when this involves twisting or vibrating the spine, can lead to injury and back pain. An inactive job or a desk job may also lead to or contribute to pain, especially if you have poor posture or sit all day in an uncomfortable chair.

Cigarette smoking: Although smoking may not directly cause back pain, it increases your risk of developing low back pain and low back pain with sciatica. (Sciatica is back pain that radiates to the hip and/or leg due to pressure on a nerve.) For example, smoking may lead to pain by blocking your body's ability to deliver nutrients to the discs of the lower back. Or, repeated coughing due to heavy smoking may cause back pain. It is also possible that smokers are just less physically fit or less healthy than nonsmokers, which increases the likelihood that they will develop back pain. Furthermore, smoking can slow healing, prolonging pain for people who have had back injuries, back surgery, or broken bones.

How Is Back Pain Diagnosed?

Diagnosing the cause of back pain requires a medical history and a physical exam. If necessary, your doctor may also order medical tests, which may include x rays.
During the medical history, your doctor will ask questions about the nature of your pain and about any health problems you and close family members have or have had. Questions might include the following:

• Have you fallen or injured your back recently?
  
• Does your back feel better – or hurt worse – when you lie down?
  
• Are there any activities or positions that ease or aggravate pain?
  
• Is your pain worse or better at a certain time of day?
  
• Do you or any family members have arthritis or other diseases that might affect the spine?
  
• Have you had back surgery or back pain before?
  
• Do you have pain, numbness and/or tingling down one or both legs?
  

During the physical exam, your doctor may

• watch you stand and walk
  
• check your reflexes to look for slowed or heightened reflexes, either of which might suggest nerve problems
  
• check for fibromyalgia by examining your back for tender points, which are points on the body that are painful when pressure is applied to them
  
• check for muscle strength and sensation
  
• check for signs of nerve root irritation.
  

Often a doctor can find the cause of your pain with a physical and medical history alone. However, depending on what the history and exam show, your doctor may order medical tests to help find the cause.

Following are some tests your doctor may order:

X rays: Traditional x rays use low levels of radiation to project a picture onto a piece of film (some newer x rays use electronic imaging techniques). They are often used to view the bones and bony structures in the body. Your doctor may order an x ray if he or she suspects that you have a fracture or osteoarthritis, or that your spine is not aligned properly.

Magnetic Resonance Imaging (MRI): MRI uses a strong magnetic force instead of radiation to create an image. Unlike an x ray, which shows only bony structures, an MRI scan produces clear pictures of soft tissues, too, such as ligaments, tendons, and blood vessels. Your doctor may order an MRI scan if he or she suspects a problem such as an infection, tumor, inflammation, or pressure on a nerve. An MRI scan, in most instances, is not necessary during the early phases of low back pain unless your doctor identifies certain "red flags" in your history and physical exam. An MRI scan is needed if the pain persists more than 3-6 weeks, or if your doctor feels there may be a need for surgical consultation. Because most low back pain goes away on its own, getting an MRI scan too early may sometimes create confusion for the patient and the doctor.

Computed Tomography (CT) scan: A CT scan allows your doctor to see spinal structures that cannot be seen on traditional x rays. It is a three-dimensional image that a computer creates from a series of two-dimensional pictures that it takes of your back. Your doctor may order a CT scan to look for problems including herniated discs, tumors, or spinal stenosis.

Blood tests: Although blood tests are not used generally in diagnosing the cause of back pain, your doctor may order them in some cases. Blood tests that might be used include the following:

• Complete blood count (CBC), which could point to problems such as infection or inflammation
  
• Erythrocyte sedimentation rate (also called sed rate), a measure of inflammation that may suggest infection. The presence of inflammation may also suggest some forms of arthritis or, in rare cases, a tumor.
  

It is important to understand that medical tests alone may not diagnose the cause of back pain. In fact, experts say that up to 90 percent of all MRI scans of the spine show some type of abnormality, and sometimes the x rays and CT scans of people without pain show problems. Similarly, even some healthy pain-free people can have elevated sed rates.

Only with a medical history and exam - and sometimes medical tests - can a doctor diagnose the cause of back pain. Many times, the precise cause of back pain is never known. In these cases, it may be comforting to know that most back pain gets better whether or not you find out what is causing it.