Though there are still many unanswered questions concerning why this is so, women with diabetes need to know their risk factors and how to prevent osteoporosis.

Osteoporosis is a bone condition characterized by low bone mass and poor bone quality.

The body breaks down more bone than is being built, resulting in thin, fragile bones that are susceptible to breaking.

Osteoporosis has no symptoms; a fracture is the biggest indication that a woman may have osteoporosis. Osteoporosis can cause pain, disability, and even premature death.

Diabetes And The Bone Connection

The health, structure, and strength of a person's bones are maintained by a natural process called bone turnover, which balances the action of osteoblasts and osteoclasts. Osteoblasts build bone and osteoclasts break it down.

In some studies, it has been suggested that poor blood sugar control impairs bone turnover, therefore shifting the balance in favor of bone loss. More studies are needed to confirm these findings, but evidence is accumulating that having either type 1 or type 2 diabetes increases a woman's risk of bone fracture.

* Type 1. Insulin is needed for cells to make bone. If a woman is not producing insulin, it is possible that she won't make enough new bone to keep up with the bone breakdown rate.

Type 1 diabetes is usually diagnosed during the teen or early adult years, when bone mass is still being accumulated. If there is insufficient insulin during this time, it is possible that a young woman will have less bone mass than normal.

A study of women in Norway showed that women with type 1 diabetes had a six-fold increased risk of developing a hip fracture when compared with women without diabetes.

In the Iowa Women's Health Study, women with type 1 diabetes were more likely to have lower body mass density if they had diabetes for more than five years. They were also 12 times more likely to have a fracture.

Secondary causes of osteoporosis, such as Grave's disease, primary hyperparathy-roidism, and celiac disease, also occur more often in women with type 1 diabetes.

* Type 2. The Iowa Women's Health Study also looked at more than 1,500 women with type 2 diabetes over a span of 11 years. The study found that, on average, women with type 2 diabetes have a higher body mass index (BMI), a larger waist line, are less physically active, have less energy, and are less likely to use estrogen than women who do not have type 2.

Women with type 2 diabetes had a 1.7-fold increased risk of developing a hip fracture. The likelihood of developing a fracture increased with duration of the diabetes. The risk was doubled in women who had type 2 diabetes for over 13 years.

Body Weight Influences Bone Mass Density

A subset study of a large national bone study looked at the effect of diabetes and BMI on bone density in post-menopausal women. This study found that, when compared with women without diabetes, women with diabetes had a higher bone density when their BMI was over 25 (a BMI of 25 or greater is considered overweight).

This confirmed previous studies indicating that heavier women had higher bone mass density. The study also showed that women with higher BMIs produced more estradiol (estrogen), the hormone that helps keep bones strong.

Because heavier women with type 2 had higher bone mass and produced more estradiol, it was long assumed that they were protected against bone loss. But researchers are now questioning that assumption.

The relative health of bone is often estimated by scans that indicate bone mass density. These scans are used to predict osteoporosis, and the results are reported as a Z-score. A Z-score of 0 to -1 is considered normal, with no increased risk of fracture.

A score of -1 to -2.5 means low bone mass, and a score of -2.5 or lower indicates the presence of osteoporosis. The lower the Z-score, the greater a woman's risk of a fracture.

The bone mass density scan can reveal the amount of calcium in the bone. According to many experts, these scans aren't a perfect test for predicting all risks for fractures because they don't detect the microarchitecture or geometry of the bone (how it is deposited or laid down).

To measure this requires measuring the rate of bone turnover. Thus far, the tests used to measure bone turnover are not consistently reliable.

Furthermore, they note that most women who are overweight are sedentary. The more sedentary the woman, the less likely she is to have the coordination and balance needed to help protect herself during a fall.

HRT Use

Hormone replacement therapy (HRT), specifically estrogen plus progesterone, has been found to be helpful in preventing osteoporosis.

In the Iowa Women's Health Study, women who stopped taking or never used HRT had almost a two-fold increased risk of developing a fracture when compared with current users of HRT.

While HRT has been approved for the use of preventing bone loss, it has also been found to increase the risk of deep vein thrombosis, breast cancer, and heart disease. Bloating, breast tenderness, and irritability are common side effects. Check with your doctor to determine if HRT is right for you.

Risk Factors

Various factors can put women at risk for developing fractures.

• Retinopathy and cataracts may result in limited vision.
• Neuropathy can disrupt one's balance and gait, increasing the risk for falls.
• Low blood sugar disrupts focus, attention, and coordination. Women who get up during the night to urinate are at increased risk.
• Chronic renal disease can interfere with bone architecture and strength.
• Gastroparesis interferes with the absorption of nutrients, leading to bone loss.
• Anorexia also interferes with nutrient absorption.

Women using the injectable contraceptive Depo-Provera may experience loss of bone density. In a study of 457 women, 18 to 39 years old, those using Depo-Provera had significant bone loss at the spine or hip compared with non-users. Bone density returned to normal within 30 months after Depo-Provera was discontinued.

Any nontraumatic fracture experienced between 20 and 50 years of age is associated with a 74-percent risk of future fractures after the age of 50. A nontraumatic fracture is a fracture unrelated to a motor vehicle accident.

So, women who have had a nontraumatic fracture are at higher risk for developing osteoporosis and fracture of the spine or hip in the future.

Women in cold climates may not get enough vitamin D during the fall and winter months. This can lead to significant bone loss.

Smoking can also contribute to bone loss.

Staying Healthy For The Future

Once a year, review your risk factors with your doctor. Determine how to increase the amount of vitamin D and calcium in your diet and supplements. Check with your doctor or health care team about doing weight-bearing exercise.

For example, one study at the Mayo Clinic found that doing 10 minutes a day of back strengthening exercises over two years helped to prevent spinal fractures.

Consult a physical therapist if you are at risk for falls, have problems with your balance or gait (walking steadily), or have poor vision. Before starting any exercise, consult with your physician.

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