GH1 and chronic obstructive pulmonary disease: The regression equations of DHEA and GH with age indicated that one-year age increase was associated with a 1.26 units decrease in DHEA and 0.032 units decrease in GH.In the present study, the difference in DHEA between COPD patients and controls was, on average, 30.2 μg/dL, indicating that the biological age of a COPD patient is, on average, about 30.2/1.26 = 24, that is, 24 years older than the age of a control subject of the same age.