We also checked the concentration of apelin in the group of smoking women with PCOS divided according to the HOMA-IR values of <2.0 (n = 19) or ≥2.0 (n = 11) and revealed a significantly decreased concentration in the group of smoking women with HOMA-IR ≥ 2.0 compared to the group with HOMA-IR < 2.0 (data not included in the tables). The gene discussed is APLN; the disease is polycystic ovary syndrome.