Some small studies have shown that low-dose GH treatment for adults with severe GH deficiency, such as that produced after surgical removal of the pituitary gland, produces positive changes in body composition by increasing muscle mass, decreasing fat mass, increasing bone density and muscle strength; improves cardiovascular parameters (i.e. decrease of LDL cholesterol), and improves quality of life without significant side effects. The extension of this approach to healthy elderly people is an area of current research, with a 2000 review in "Hormone Research" commenting that "Clearly more studies are needed before GH replacement for the elderly becomes established." and noting that "safety issues will require close scrutiny".