Reasons, Procedure & Test Scores For Bone Mineral Density

Submitted on March 27, 2012

Bone mineral density or BMD refers to the density of minerals contained per cubic meter of the bones in your body. A bone mineral density test will help you to assess the strength of your bones and can proactively help to identify a condition called Osteopenia. It is also used to confirm if the patient already has Osteoporosis.

Osteopenia occurs when the bone density is low and can lead to fracture of the bones. Osteopenia can eventually lead to Osteoporosis if it is not identified on time. Osteoporosis is a condition in which the bones become extremely thin and brittle, increasing the risk of the bone getting fractured.

Reasons for Reduction of Bone Density

There are many reasons that can contribute to the reduction in the density of the bone, thus leading to Osteoporosis. Some of the most well known reasons are:

  • Age: As we grow older the bones start wearing away naturally which reduces the bone density.
  • Early menopause: An early menopause causes the estrogen levels in your body to drop and Estrogen plays a vital role in building the density of the bones.
  • Family history of hip fracture: It has been found that individuals with a family history of hip fracture are more prone to Osteoporosis.
  • Low body weight: Individuals with a low body weight are at a higher risk when it comes to the development of Osteoporosis.
  • Lack of calcium in the diet: Calcium plays a vital role in increasing the strength of our bones. A lack of calcium in the diet can lead to Osteoporosis.
  • Smoking, alcoholism and lack of exercise can also lead to a reduction of the bone density.

Test procedure

The Bone Mineral density test or BMD test is usually performed using a technique called as bone densitometry. DEXA or “Dual energy x-ray absorptiometry” is the most commonly used densitometry technique. It is a painless technique and can provide precise details on even small amounts of bone density reduction. There are several other methods based on the CT Scan and ultrasound that are also used to measure bone density. These are called QCT and QUS.

The result of a BMD test is called a T-Score and is expressed as a Standard Deviation. The average BMD of a large group of healthy 30 year olds is used as a baseline to derive your T-score. After your BMD has been measured it is compared against this average.

Bone mineral density test scores

Your T-score may be negative if your bone density is lesser than that of an average 30 year old and positive if it is higher. You may use the following scale to interpret the T-score values:

Normal: Standard deviation or SD is less than 1 indicates that you are normal. Osteopenia: SD between 1 and 2.5 shows signs of low bone density. Osteoporosis: An SD of 2.5 or greater indicating that the bones have become very fragile and thin.

It is also important to know that cancer, consuming certain types of medicine and Vitamin D deficiency, can impact the BMD.