When you think of the possible risk factors for osteoporosis, you probably can name several of the well-recognized ones—like having a family history of fractures or a low body weight or being older, female, or inactive.
But what may not immediately come to mind is that certain chronic diseases can interfere with bone health and increase your fracture risk. One of those diseases is diabetes.
If you have diabetes, here’s what you need to know.
Evidence for a diabetes-fracture link
Numerous studies have shown a connection between diabetes and bone fractures—particularly hip fractures. Results from the Nurses’ Health Study found that women with type 1 diabetes were six times more likely than women without diabetes to have a hip fracture. Women with type 2 diabetes had more than twice the risk.
Even after controlling for factors that increase the chances of both fractures and diabetes, such as age, body weight, and physical activity, the elevated risk remained.
Similar findings have been reported in studies that included men.
Vertebral fractures may also be a concern. A 2016 study in International Orthopaedics found that people with diabetes were twice as likely to suffer a vertebral fracture compared with their nondiabetic counterparts.
Explaining the link
A logical explanation is that people with diabetes have lower bone mineral density than people without diabetes. Research shows that this is true for people with type 1 diabetes but not type 2 diabetes.
Type 1 diabetes occurs when the body destroys its own pancreas; this leads to a deficiency of insulin. Insulin is essential in promoting bone strength and growth and helping children and young adults achieve their peak bone mass.
What’s more, type 1 diabetes typically develops before age 30—the time when most people are building bone to reach their peak bone mass.
But a lack of insulin is only one factor contributing to an increased risk of fractures in individuals with type 1 diabetes. In addition, it doesn’t explain the increased fracture risk in those with type 2 diabetes, which usually arises in middle age and is mostly related to decreased insulin sensitivity rather than reduced insulin production. So investigators have proposed several other explanations.
• Blood glucose levels. People with poorly controlled diabetes have high blood glucose levels (hyperglycemia), which may directly affect bone quality—an indicator of bone strength not measured by a bone density test.
High blood glucose levels also increase your risk of diabetes complications such as compromised eyesight, kidney dysfunction, and neuropathy, many of which raise the likelihood of falls and fractures.
Conversely, people who take certain diabetes medications, particularly insulin, are at risk for hypoglycemia (low blood glucose levels) when they do not closely match drug doses to food intake and physical activity.
Symptoms of hypoglycemia like dizziness, lack of coordination, and muscle weakness can increase your risk of falls and thus fractures.
• Obesity. People with type 2 diabetes tend to have normal or elevated bone mineral density and to be overweight, both of which typically help protect against fractures.
Although it’s not clear why people with type 2 diabetes actually have an increased risk of fracture, some research suggests that excessive body fat may trigger an inflammatory process that ultimately inhibits bone formation and stimulates bone resorption.
• Diabetes complications. People with diabetes are at high risk for a host of complications, including eye disease, nerve problems, cardiovascular disease, and kidney dysfunction.
Eye problems like diabetic retinopathy, cataracts, and glaucoma can impair vision, increasing the chances of falls.
Nerve problems, especially those in the feet and legs, can negatively affect balance and make falls more likely.
Cardiovascular disease causes plaque buildup and narrowing of the arteries, which may decrease blood flow to the bones and have a detrimental effect on bone quality.
Last, people with diabetes-related kidney disease develop a characteristic bone disease that results from the inability to make the active form of vitamin D, and parathyroid overactivity, which leads to fractures.
• Medications. A class of drugs known as thiazolidinediones, used to treat type 2 diabetes, may be a culprit, too.
A review of 12 studies—including 10 randomized, controlled trials and more than 45,000 people—found that women with type 2 diabetes who used thiazolidinediones for a year or more had twice the risk of fracture as nonusers. Similar findings have been reported for male thiazolidinedione users.
Researchers believe that thiazolidinediones cause bone marrow stem cells to become adipocytes (fat cells) rather than osteoblasts (cells responsible for bone formation). Thiazolidinediones approved in the U.S. are rosiglitazone (Avandia) and pioglitazone (Actos); drugs that contain a thiazolidinedione include Avandaryl, Avandamet, Actoplus Met, and Duetact.
Postmarketing studies on the diabetes drug canagliflozin (Invokana, Invokamet) suggest that it, too, may increase the risk of bone fractures and decrease bone mineral density. The finding prompted the FDA to require the manufacturer to strengthen its warning about adverse bone effects on the drug’s label in 2015.
Reduce your fracture risk
If you have diabetes, the following steps can help reduce your fracture risk:
• See your ophthalmologist regularly. Vision problems can increase your risk of falling and sustaining a fracture. See your eye doctor for a checkup every six to 12 months, take your eye medication as prescribed, and call your doctor right away if you develop vision problems between regularly scheduled visits.
• Control your glucose levels. Episodes of hypoglycemia (low blood sugar level) or hyperglycemia (high blood sugar level) can raise your risk of diabetes complications as well as falls and fractures.
To lower the risks, follow your doctor’s advice on diet and exercise, take your medications as prescribed, and routinely check your blood glucose levels at home.
Your doctor should measure your A1c levels with a blood test every three to six months. The test is an indicator of your average blood glucose level over the past few months. An A1c level of less than 7 percent is recommended for most adults.
• Monitor your calcium and vitamin D intake. To strengthen your bones, the National Osteoporosis Foundation recommends 1,000 mg of calcium (from diet and supplements combined) and 400 to 800 IU of vitamin D a day for men and women under age 50.
If you are 50 or older, try to consume 1,200 mg of calcium and 800 to 1,000 IU of vitamin D daily.
• Get moving. Exercise is a win-win situation for people with diabetes and osteoporosis. It can help reduce blood glucose levels and increase your bone strength.
Aim for at least 30 minutes of low-impact, weight-bearing exercises like walking or low-impact aerobics on most—and preferably all—days of the week. Also, be sure to incorporate activities into your exercise routine that help develop muscle strength and improve balance.
Before starting a new exercise regimen, check with your doctor first for any restrictions or any dietary or medication modifications you might need to make.
If you’re not sure how to get started, ask your doctor to refer you to a physical therapist who can develop an exercise regimen that meets your osteoporosis and diabetes needs.
• Stop smoking. Smoking is a known risk factor for hip fractures in women and men, and studies show that smoking cessation can reduce your risk. If you’re having difficulty quitting, talk to your doctor about smoking cessation methods that can significantly increase your odds of success.
• Review your medications. If you have osteoporosis and are taking a diabetes medication that increases fracture risk, ask your doctor if there is an effective alternative.
If you continue the drug, ask your doctor to evaluate your other risk factors for a fracture and whether you should take additional measures to safeguard the health of your bones.
If you're at risk for a bone fracture, keep these prevention tips in mind.