Prevalence and incidence of anemia in the German Heinz Nixdorf Recall Study.

This study aims to determine prevalence and incidence of anemia in the general population in Germany and evaluate a potential role of serum-free light chains (FLC) as biomarker in anemia. The population-based Heinz Nixdorf Recall Study comprises 4,814 men and women aged 45-75 years. Hemoglobin <13 g/dl in men and <12 g/dl in women defined anemia. Laboratory data was used to classify cases into renal, iron deficiency (IDA), vitamin B12/folic acid deficiency, anemia of chronic disease (ACD), and unexplained anemia (UA). Follow-up data was available from annual questionnaires, death certificates, and 5-year follow-up visit (5-year FU). Anemia cases (152) were identified (prevalence 3.2 %, 95 % CI 2.7-3.7). In participants aged 65 or older, prevalence was 4.3 % (95 % CI 2.9-6.0) in both men and women. Main anemia subtypes were: IDA 19 %, ACD 25 %, and UA 44 %. Incidence increased with age and was 12.8/1,000 person-years and 10.9/1,000 person-years in men and women aged 65 or older, respectively. UA was characterized by elevated FLC. Participants with elevated FLC and high-sensitivity C-reactive protein (hsCRP) had an increased risk of anemia at 5-year FU. FLC-alone or in combination with hsCRP-may serve as biomarker indicating an increased risk of developing anemia.