T2D Fracture Risk Likely Due to Impaired Physical Function

Poorer physical function, not poorer bone mineral density (BMD), could be the principal reason for the increased fracture risk in older women with type 2 diabetes (T2D), according to a Swedish prospective observational study in JAMA Network Open.

The study was conducted in more than 3000 Swedish women by Mattias Lorentzon, MD, a professor of geriatric medicine at Gothenburg University, and chief physician at the Osteoporosis Clinic at Sahlgrenska University Hospital in Mölndal, and colleagues.

Older women with T2D had higher BMD, better bone microarchitecture, and a similar bone material strength index (BMSi) but poorer physical performance and higher fracture risk than women without diabetes.

Women with T2D had 9.1% higher body weight, a 9.5% higher body mass index (BMI), and 6.3% higher appendicular lean mass index (lean mass divided by height squared) than controls.

The T2D group also had a lower prevalence of reported osteoporosis medication use vs controls: 3.4% vs 7.5%, respectively.

Prolonged diabetes treatment and insulin use were associated with higher fracture risk and poorer physical performance despite better bone characteristics.

“Our results demonstrate that checking and monitoring physical function is important to identify diabetes patients with a high risk of fractures and suggest that improving physical function may be important to reduce the risk of fractures in these patients,” Dr. Lorentzon told this news organization.

He speculated that the better bone microarchitecture in women with T2D could be due to both higher body weight and adiposity as well as to hormonal differences such as higher estradiol levels.

Study Details

A fractures study was performed in the Gothenburg area from March 2013 to May 2016 with follow-up of incident fracture data completed in March 2023. Data were collected from questionnaires and through examination of anthropometrics, physical function, and bone measurements using dual-energy x-ray absorptiometry and high-resolution peripheral computed tomography. A subsample underwent bone microindentation to assess BMSi.

Among the cohort’s 3008 women, ages 75-80 (mean, 77.8), 294 patients with T2D were compared with 2714 same-age unaffected women.

During a median follow-up of 7.3 years, 1071 incident fractures, 853 major osteoporotic fractures, and 232 hip fractures occurred. In models adjusted for age, BMI, clinical risk factors, and femoral neck BMD, T2D was associated with an increased risk of any fracture: hazard ratio (HR), 1.26; (95% CI, 1.04-1.54), and major osteoporotic fracture (HR, 1.25; 95% CI, 1.00-1.56).

Most fractures were due to falls, with the most common affected sites being the forearm, upper arm, spine, and hip, Dr. Lorentzon said.

Among the findings:

• In bone microarchitecture, women with T2D had higher BMD at all sites: total hip, 4.4% higher; femoral neck, 4.9% higher; and lumbar spine, 5.2% higher.
• At the tibia, the T2D group had 7.4% greater cortical area and 1.3% greater density, as well as 8.7% higher trabecular bone volume fraction.

“Our findings regarding BMD are consistent with previous publications showing higher BMD in individuals with T2D compared with those without diabetes,” Dr. Lorentzon said. A 2012 meta-analysis, for example, showed higher BMD levels in T2D patients. “Some smaller studies, however, have found worse bone microstructure and lower bone material strength in contrast to the results from our study,” Dr. Lorentzon said.

• There was no difference in BMSi, with a mean of 78 in both groups.
• The T2D group had lower performance on all physical function tests: a 9.7% lower grip strength, 9.9% slower gait speed, and 13.9% slower timed up-and-go time than women without diabetes.

“We found all parameters regarding physical function, such as muscle strength, balance, and performance, were much worse in women with diabetes than in those without,” Dr. Lorentzon said. “Dizziness could also be a contributor to the increased risk of falls, but this factor was not investigated in our study.”

Commenting on the study but not involved in it, Anthony J. Pick, MD, an endocrinologist at Northwestern Medicine Lake Forest Hospital in Lake Forest, Illinois, said sarcopenia is a common and often under-recognized problem in older adults and is especially prevalent in T2D, obesity, and heart failure. “I believe that ‘exercise is medicine’ is a key concept for metabolic and osteoporosis patients — and wellness and longevity in general — and I certainly hope studies like this drive awareness of the importance of engaging in strengthening exercises.”

Dr. Pick noted some nuances in this study suggesting there may be some impairments in bone quality beyond the strength and fall risk issue, “so this is likely a complex area.”

This study was supported by the Swedish Research Council, the Inga-Britt and Arne Lundberg Foundation, and Sahlgrenska University Hospital. Dr. Lorentzon reported personal fees from UCB Pharma, Amgen, Parexel International, Astellas, and Gedeon Richter outside the submitted work. Coauthor Dr. Johansson reported lecture fees from Union Chimique Belge (UCB) Pharma outside the submitted work. Dr. Axelsson reported personal fees from Amgen, Meda/Mylan, and Lilly outside the submitted work. Dr. Pick had no relevant conflicts of interest.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.