I've never heard of ibuprofen being known to cause osteoporosis. Osteoporosis is more associated with using prescription steroids for things like asthma or Crohn's.

Advil is very toxic as you said though. People think it's safer than it really is simply because it's available without a prescription.

The most common toxic effects are kidney failure, high blood pressure, bleeding, stomach ulcers & increased risk of cardiovascular events.