This study tests if a drug called **zoledronic acid (ZA)** helps prevent bone fractures in people aged 60+ with Parkinson's Disease (PD) or similar conditions. **Parkinsonism** is a condition that causes symptoms similar to Parkinson's Disease. The study is **randomized**, meaning participants are randomly chosen to receive either the actual drug or a placebo (a harmless pill with no effect), and **blinded**, so neither participants nor researchers know who gets which treatment. It lasts at least 2 years with **2650 participants** in the US.
Participants will get one ZA infusion at home, simplifying treatment since no extra doctor visits or bone tests are needed. They will also take vitamin D3 daily for 2 months. Every 4 months, researchers will check if participants have had any fractures. Eligible participants must be willing to continue follow-ups for at least 2 years.
- Study is home-based, reducing the need for medical visits.
- Participants must be 60+ and have PD or similar conditions.
- Excludes those with recent hip fracture or certain drug treatments.