IL33 and osteoporosis: Studies in postmenopausal women revealed significantly elevated serum IL-31 levels (43.12 ± 6.97 pg/mL vs. 29.58 ± 6.09 pg/mL in healthy controls) and significantly reduced IL-33 levels (3.53 ± 2.45 pg/mL vs. 13.72 ± 5.39 pg/mL) in osteoporosis patients (24, 25).