Thinner bone is at higher risk to break and can be a sign of developing osteoporosis, in which bone density dips dangerously low. Think of the difference between a thin, brittle twig and a thick, firm tree branch -- denser is better to avoid a sudden snap.
The University of Pittsburgh's Elsa Strotmeyer, PhD, and colleagues conducted the study, which appears in Diabetes Care.
The researchers checked the women's height, weight, and bone density. The women also completed surveys about health habits that can help bones (such as weight-bearing exercise) or hurt bones (such as smoking, heavy drinking, use of certain medications, and skimping on calcium and vitamin D).
Weaker Bones With Type 1 Diabetes
Even after adjusting for those factors, women with type 1 diabetes had lower bone density than those without diabetes.
In addition, a third of women with type 1 diabetes reported having a bone fracture after age 20, compared with less than a quarter of those without diabetes.
It's not known if the results apply to men or to people with type 2 diabetes, since they weren't included in the study.
Most people with diabetes have type 2 diabetes, which usually starts later in life than type 1 diabetes. For instance, in Strotmeyer's study, women with type 1 diabetes had been diagnosed at age 10, on average, and had had type 1 diabetes for more than 30 years.
Bone Density Tests
To measure the women's bone density, the researchers used a DEXA (dual-energy X-ray absorptiometry) machine. The machine checked the women's overall bone density as well as the density of their hips, neck, and spine.
Bone density peaks in the 30s. After that, bones gradually lose density over time. Bone density tests usually aren't done until after menopause, since that's when bone density starts to decline at a greater rate.
If the study's findings are correct, type 1 diabetes could join the list of other osteoporosis risk factors, which include:
- Being postmenopausal
- Having a family history of osteoporosis
- Being of European or Asian ancestry
- Having a medical condition such as hyperthyroidism that makes it hard to absorb enough calcium
- Having a small frame
- Being a smoker
Treating osteoporosis can mean taking prescription drugs, boosting intake of calcium, vitamin D, and other bone-friendly nutrients, and getting weight-bearing exercise. Walking, jogging, hiking, dancing, and lifting weights are some examples of weight-bearing exercise. Biking and swimming aren't in that group, since the bike or water carries your weight.