Abstract: Objective To investigate the serum level of vitamin D in the middle-aged and elderly women and the correlation with anemia. Methods A total of 332 middle-aged and elderly women in Medical Examination Center of Jiangsu Province Hospital from January 2019 to September 2020 were selected. The levels of serum 25-hydroxy vitamin D [25-(OH)D] and red blood cell parameters were detected. The correlation between 25-(OH)D and red blood cell parameters was analyzed by Spearman correlation analysis. Results The serum 25-(OH)D level of 332 middle-aged and elderly women was 42.60 (19.10-73.10) nmol/L, 25-(OH)D deficiency accounting for 69.28%, 25-(OH)D insufficiency accounting for 30.72%. The level of 25-(OH)D in middle-aged group (aged 45-59 years old, n=270) was higher than that in elderly group (aged 60-79 years old, n=62), and the difference was statistically significant (Z=-5.140, P<0.001); The level of 25-(OH)D in summer to autumn group (detection from May to October, n=225) was significantly higher than that in winter to spring group (detection from November to April of the next year, n=107), and the difference was statistically significant (Z=-5.577, P<0.001). In the middle-aged group and the elderly group, there were no differences in the rate of anemia between 25-(OH)D insufficiency subgroup and 25-(OH)D deficiency subgroup (χ² =3.112, 1.079; P=0.078, 0.299). In the middle-aged group, the levels of red blood cell (RBC), hemoglobin(Hb), hematocrit (HCT), mean corpuscular volume (MCV) and mean hemoglobin concentration (MCHC) in the 25-(OH)D insufficiency subgroup were significantly higher than those in the 25-(OH)D deficiency subgroup (P<0.05). In the elderly group, the levels of RBC and HCT in the 25-(OH)D insufficiency subgroup were significantly higher than those in the 25-(OH)D deficiency subgroup (P<0.01). In the middle-aged group, RBC and Hb were independently correlated with 25-(OH)D (β=14.545, 0.103; P<0.05); In the elderly group, RBC and HCT were independently correlated with 25-(OH)D (β=9.939, 0.672; P<0.05) . Conclusions Vitamin D deficiency and insufficiency is prevalent in middle-aged and elderly women. Vitamin D deficiency can affect the levels of red blood cell parameters.

Key words: middle-aged and elderly women, 25-hydroxy vitamin D, anemia, red blood cell parameters