A multi-state, 2 year study in the US published in the Journal Arts & Heath monitored medication usage of two groups: one group that resided in long term care and one group that resided in long term care AND participated in a regular group music program 3 times per week.
The participants in the music program reported a higher overall rating of physical health, fewer doctors visits, less medication used, and fewer instances of falls compared to the control group.
The author of the study suggests that if all persons who fall under what is classified as Medicare D (national health coverage for those aged 65 and older in the US) participated in the music program with similar results as in the study, the savings would equal $6.3 BILLION DOLLARS!
(Thanks JB Music Therapy for finding this one)