Association between anemia and vitamin D deficiency in German seniors : A retrospective data analysis.

Background: Anemia and deficiency of vitamin D (VDD) are frequently seen in seniors and an association is suspected. Approximately one third of the German population is affected by VDD, with a rising prevalence among seniors.

Aim: To analyze the association between anemia and VDD among German seniors aged ≥ 60 years.

Methods: Retrospective cross-sectional data analysis (n = 4008) in a nationwide working laboratory medical center (January-December 2019). Study parameters included amongst others: hemoglobin (Hb), calcifediol (25D) and calcitriol (1.25D), glomerular filtration rate (GFR) to assess the kidney disease outcomes quality initiative (KDOQI) state. The inclusion criteria were age ≥ 60 years, normal C‑reactive protein (CRP) and leucocyte levels.

Results: The 25D was estimated in 4008 patients and 1.25D only in 411 patients. Mean age 75 years (± 8.61 years; 60-99 years) with 30.6% males; mean GFR 62 ml/min/1.73 m³ (± 22.74); 20% of patients were anemic, 35% were deficient for 25D (< 50 nmol/l), with men > women (p = 0.014). Linear regression analysis revealed a significant effect of 25D values < 30 nmol/l on hemoglobin in males of KDOQI I-III and females of KDOQI I-IV (R2 = 0.052; p = 0.005; and R2 = 0.124; p < 0.001, respectively). For 1.25D a weak but significant effect on hemoglobin independent of KDOQI was only seen in women (R2 = 0.200; p = 0.005).

Conclusion: In this cohort deficiency of 25D and 1.25D was significantly associated with hemoglobin independent of renal function only in women but not in men.