Diabetes and bones
In the past, it was thought that risk of osteoporosis was increased in people with Type 1 diabetes but not in those with Type 2 diabetes. More recent research suggests this may not always be the case. The reasons for changes in bone metabolism in diabetes are not completely clear, but they likely include lack of insulin, high blood glucose levels, and changes in vitamin D and calcium metabolism.
People who develop Type 1 diabetes in childhood or adolescence tend to have decreased bone mass as adults and are more likely to develop osteoporosis and experience fractures than people who don’t have diabetes. It is thought that lack of insulin, which is a growth factor for bone, causes poor bone growth and lower peak bone mass in adolescents with Type 1 diabetes. High blood glucose levels may also cause poor bone growth, though studies of blood glucose control and bone mineral density have not always shown a link between the two.
People with Type 1 diabetes have also been shown to have reduced levels of vitamin D on diagnosis and abnormal seasonal changes in vitamin D levels, which could contribute to poor bone growth. Other conditions that can increase risk of osteoporosis, such as gluten intolerance (also called celiac disease) and thyroid disorders, are also more common in Type 1 diabetes.
Research studies of people with Type 2 diabetes have found increases, decreases, and no change in bone mineral density associated with diabetes. It is true that people with higher body weights tend to be protected against bone loss, and many people with Type 2 diabetes are overweight, but several studies have found that people with Type 2 diabetes experienced a greater number of fractures than people without diabetes, while others have found significant bone loss in people with Type 2 diabetes compared to age- and sex-matched control subjects. Other studies have found low serum vitamin D levels in postmenopausal women with Type 2 diabetes.
No matter what type of diabetes a person has, diabetes-related complications such as hypoglycemia, retinopathy and vision loss, and changes in balance caused by neuropathy, can increase the risk of falls and fractures.
Osteoporosis can be diagnosed with a test called a bone mineral density test. The most accurate form of bone mineral density testing is called dual energy x-ray absorptiometry, or DEXA. This test uses a very small amount of radiation, less than a common x-ray, to measure the amount of calcium and tissue that you have in your bones. It is painless and takes about 10 to 15 minutes to perform. Many health clinics and physician’s offices offer bone mineral testing right in their office, and Medicare will pay for these tests for beneficiaries who are at risk for developing osteoporosis. The US Preventive Services Task Force has issued recommendations that all women 65 and older be screened for osteoporosis, as well as younger women whose risk of osteoporosis is equal to that of a 65-year-old white woman with no additional risk factors.
After you get your bone mineral density tested, your physician will compare your results against a “normal” standard. One standard, the T-score, compares your bone mineral density to an average, healthy 30-year-old’s bone density. The other standard, the Z-score, compares your bone mineral density to that of a typical healthy person of your age and body size. Because most people lose bone as they age, the age-matched Z-score is less useful in determining risk.