Use of Prolia to Treat Osteoporosis

We were asked a question about the use of Prolia to treat osteoporosis in individuals with Down syndrome. Osteoporosis is a condition in which a person's bones become brittle or weak. It can lead to an increase in fractures. Prolia is a prescription medication that is injected once every 6 months to prevent bone loss.

Unfortunately, the understanding of osteoporosis and its risk for fractures is limited for people with Down syndrome. The GLOBAL Medical Care Guidelines for Adults with Down Syndrome published in October 2020 shared the following: 

• Evidence is inadequate regarding osteoporosis prevention in adults with Down syndrome, including when to screen for osteoporosis, how to interpret bone mineral density (BMD) values, what the thresholds should be for initiating pharmacotherapy, and how to choose pharmacotherapy agents.

• There is no evidence comparing effectiveness of preventive measures in people with Down syndrome versus without Down syndrome.

• Epidemiology of fragility fractures in adults with Down syndrome is poorly understood but likely differs significantly from adults without Down syndrome.

• A shared decision-making discussion should include potential risks, benefits, and uncertainties around osteoporosis screening and potential preventive measures, including medications, exercise and vitamin D supplementation.

Additional information can be found on pages 42-44 of the GLOBAL guidelines. Here are a few additional things to consider: 

• Bones are in a state of constant turnover; bone is constantly being remodeled. Bones have cells called osteoclasts that break down the bone. They also have cells called osteoblasts that build up the bone. 

• People with Down syndrome are thought to have both low osteoclast activity and low osteoblast activity. Overall, there is lower bone turnover.

• The function of medications like Prolia is to reduce osteoclastic activity (breakdown of the bone). Since the osteoclast activity is already low in people with Down syndrome, it is not clear how effective Prolia is for people with Down syndrome (because its function is to reduce osteoclastic activity). 

• As recommended in the GLOBAL guidelines, we recommend checking vitamin D level and supplementing as appropriate based on the value. We also recommend assessing calcium intake and supplementing as appropriate based on the intake. 

• More information on osteoclasts and osteoblasts in people with Down syndrome can be found in this research article: Low Bone Turnover and Low Bone Density in a Cohort of Adults with Down Syndrome .