Anemia May Increase the Overall Risk of Cancer: Findings from a Cohort Study with a 12-Year Follow-up Period in South Korea.

Abstract

No previous study has assessed cancer risk in individuals with anemia diagnosed based on hemoglobin levels. Thus, we aimed to investigate whether anemia increases the risk of cancer. Adult individuals who underwent a standardized medical examination during 2002 and 2003 in South Korea were included, and their cancer status was evaluated between January 2004 and December 2015 (12 years) as a primary endpoint. Anemia was defined as serum hemoglobin levels of <12 and <13 g/dL for women and men, respectively. A total of 454,304 adults were included in the final analysis. Among them, 41,947 (9.2%) and 412,357 (90.8%) individuals constituted the anemia and control groups, respectively. After propensity score matching, a total of 83,886 individuals (41,943 per group) were included in the analysis. Cox regression revealed that the risk of cancer in the anemia group was 3% higher than that in the control group (HR, 1.03; 95% confidence interval, 1.01-1.05; P = 0.023). Specifically, relative to the control group, the anemia group was at an increased risk of gastric (HR, 1.29), esophageal (HR, 1.37), lung (HR, 1.14), and thyroid cancers (HR, 1.14), neoplasms of breast and genital organs (HR, 1.12), and lymphoma or leukemia (HR, 1.63). Anemia was independently associated with an increased overall risk of cancer. Further research is required to clarify the associated mechanism. Anemia was independently associated with an increased overall risk of cancer in the South Korean population.