CST3 and chronic obstructive pulmonary disease: Age, body mass index, overweight, chewing ability, 25-hydroxy-vitamin D, insulin-like growth factor 1, testosterone, albumin, gamma-glutamyl transferase, lipids, cystatin C, blood pressure, osteoporosis, pain, stroke, chronic kidney disease, chronic obstructive pulmonary disease, fat and protein intake, exercise, instrumental activities of daily living