Risk of hip and forearm fracture in subjects with type 2 diabetes mellitus and latent autoimmune diabetes of adults. The HUNT Study, Norway

Abstract

Type 1 and type 2 diabetes mellitus incur an increased risk of fracture, with a generally higher risk among individuals with type 1 diabetes. The fracture risk among individuals with latent autoimmune diabetes of adulthood (LADA) is not known. The present cohort study aimed to estimate the risk of hip and forearm fracture among individuals with LADA, alongside type 1 and type 2 diabetes, using data from the second survey of the Trøndelag Health Study (HUNT2) in 1995-97. All inhabitants aged 20years or older (N=92,936) were invited to attend, of whom 65,234 (70%) participated. A total of 1972 (3%) reported to have diabetes; 1399 were found to have type 2 diabetes, 144 to have LADA, and 138 to have type 1 diabetes. All participants were followed prospectively with respect to hip- and forearm fractures by linkage to the local fracture registry. During a median follow-up of 16.2years, 2695 persons with hip fractures and 3533 persons with forearm fractures were identified. There was an increased risk of hip fracture in women with type 2 diabetes (HR=1.51, 95% CI 1.24-1.85) and LADA (HR=2.15, 95% CI 1.25-3.72), whereas women with type 1 diabetes did not have a significantly increased risk (HR=2.13, 95% CI 0.89-5.14). Among men, only LADA was associated with an increased risk of hip fracture (HR=2.69, 95% CI 1.34-5.41). There was no statistically significant association between any of the diabetes types and forearm fracture. In women with type 2 diabetes, the highest risks of hip fracture were observed among those with highest HbA1c level at baseline, longest time since diagnosis, and most visual and movement impairment. We found that individuals with LADA had an increased risk of hip fracture similar to that previously reported for individuals with type 1 diabetes, and no increased risk of forearm fracture.