Role of irisin in postmenopausal osteoporosis

Osteoporosis is a systemic and metabolic bone disease characterized by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk. Irisin is a thermogenic protein that converts the white adipose tissue into brown adipose tissue. Irisin is defined as a myokine that protects individuals from metabolic diseases and is released from skeletal muscle when regular exercise is performed. Irisin have various effects on bone metabolism. Our study was conducted to investigate the relationship between osteoporosis and irisin. In this study, two groups of women between 40-65 years of age were included. Fourty patients with postmenopausal osteoporosis were included in group 1, and 40 patients with osteopenia or normal body mineral density (BMD) were included in group 2. Physical examinations and routine biochemical tests were performed at the beginning of the study. Full blood count, serum blood sedimentation rates, serum C-reactive protein (CRP), rheumatoid factor (RF), liver function tests; alanine transaminase (ALT) and aspartate transaminase (AST), alkaline phosphatase (ALP), creatine kinase (CK), calcium (Ca), phosphorus (P), parathormone (PTH), vitamin D and thyroid stimulating hormone (TSH) levels were evaluated. Bone densitometry was recorded made in the last one year. Blood samples were taken to evaluate the levels of irisin. Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO) were also evaluated. As a result of the study, no significant difference was found between the osteoporosis group (group 1) and control group (group 2) in terms of irisin levels. In Group 1, there was a negative correlation between femur total Z scores and irisin values. There was no correlation between QUALEFFO total-subscales and BMD measurements in group 1. QUALEFFO, in the assessment of life criteria; there was no significant difference between osteoporosis group and control group. No correlation was found between the irisin and BMD measurements in group 2. No correlation was found between the irisin levels and QUALEFFO total and subscales in Group 2. There was a positivecorrelation between irisin and vitamin D levels in the control group (group 2). In our study, no significant difference between the irisin levels of osteoporosis and control group patients. No significant correlation was found between irisin values and BMD measurements. Studies on the relationship between osteoporosis and irisin should be continued and researches on this subject should be expanded. Keywords: Postmenopausal osteoporosis, irisin, quality of life