Individuals with chronic obstructive pulmonary disease (COPD) may also have to worry about osteoporosis. A study of 119 patients (81 patients with COPD and 38 healthy individuals) found that one third of the COPD patients met the criteria for osteoporosis, compared with 13% of the healthy group. The results of the study showed that 80% of the patients had some indications of previously undiagnosed bone thinning, either osteoporosis or osteopenia?a precursor to osteoporosis. Furthermore, the presence of osteoporosis in the group was associated with a loss of fat-free mass. In the current study, 17 patients were shown to have lower-than-normal fat-free mass while still having normal body mass indexes. The researchers also connected elevated markers of cellular protein breakdown with both body composition and lung disease severity.