A double-blind, placebo-controlled study published in the Journal of Nutrition, Health and Aging (2015 Nov;19(9):870-7. doi: 10.1007/s12603-015-0509-9) looked at the effect supplementation of coenzyme Q10  and selenium had on elderly nursing home residents. The  443 participants were given either coenzyme Q10 and selenium or a placebo over a period of two years. At the end of the two years, a total of 206 subjects were evaluated. Health-related quality of life was measured with the Short Form-36 (SF-36), the Cardiac Health Profile (CHP) and one item overall-quality of life (overall-QoL). The group receiving the supplements scored higher in health related quality of life and spent less time in the hospital (1779 days out of the hospital for the supplemented group compared to 1533 days out of the hospital for the placebo group).