Cataracts Linked to Higher Risk of Osteoporosis, Fracture

A recent study from Taiwan found that having cataracts was independently associated with increased risks of osteoporosis and fracture, and also said there might be an association between cataract surgery and lower risks of osteoporosis and fracture.

For the population-based retrospective cohort study, researchers studied 57,972 cataract patients who were matched to 57,972 healthy controls. Data was drawn from Taiwan’s single-payer, mandatory-enrollment National Health Insurance (NHI) program, which provides universal coverage for outpatient, inpatient, and emergency services to all residents of Taiwan and covers more than 99% of the Taiwanese population.

Patients with cataracts were further divided into cataract surgery and nonsurgery groups. During an average follow-up time of 6.4 years, 17,450 patients in the cataract group developed osteoporosis or fractures, compared with 12,627 in the noncataract group.

The diagnosis of cataracts was associated with a 29% increased risk of developing osteoporosis or fracture. In analyses for each individual event, the diagnosis of cataracts was associated with a 43% increased risk of osteoporosis, a 16% increased risk of hip fracture, a 25% increased risk of vertebral fracture, and a 24% increased risk of other fractures.

In analyses for each event, cataract was significantly associated with greater likelihood of all outcomes (osteoporosis: aHR = 1.43, 95% CI = 1.37—1.50, P <.001; hip fracture: aHR = 1.16, 95% CI = 1.07—1.26, P <.001; vertebral fracture: aHR = 1.25, 95% CI = 1.18—1.33, P <.001; other fractures: aHR = 1.24, 95% CI = 1.20—1.28, P <.001).

In the cataract group, patients who underwent cataract surgery had a 42% lower risk of developing osteoporosis or fracture. Undergoing cataract surgery was also associated with lower risks of all individual events (osteoporosis; hip, vertebral, other fracture).

The researchers believe the public health implications of the study are potentially large. They noted the strength of the study was its nationwide population-based design, which provided a large sample size and long-term follow-up.

The limitations included some potential confounding factors. Personal factors, such as lifestyle, substance use, and laboratory examination data could not be accessed in the claims-based dataset and could therefore not be controlled or adjusted for. In addition, Taiwanese do not routinely undergo bone mineral density (BMD) screening, and such tests are mainly self-pay. Researchers could not obtain reliable BMD information, could not control for such factors.

Also, because the study relied on claims dataset, they could not retrieve a detailed medical history of the fractures, and could not determine whether vertebral fractures were clinical vertebral fractures or morphometric fractures.

Reference

Huang HK, Lin SH, Loh CH, Wang JH, Liang CC. Association between cataract and risks of osteoporosis and fracture: a nationwide cohort study. [published online October 3, 2018]. J Am Geriatr Soc. doi: 10.1111/jgs.15626.