High serum iron is associated with increased cancer risk

Epidemiological studies linking high serum iron with cancer risks are limited and inconclusive, despite evidence implicating body iron in human carcinogenesis. A cohort of 309,443 adults in Taiwan who had no history of cancer had serum iron levels tested at the time of recruitment (1997 – 2008). Initially measured iron levels were associated with subsequent cancer risk by linking individuals with the National Cancer Registry and National Death File. Hazard ratios were calculated by the Cox model. One-third of males (35%) and one-fifth of females (18%) had high serum iron (?120 ?g/dL), which was associated with a 25% increase in risk for incidence of all cancers (Hazard Ratio (HR): 1.25, 95% confidence interval (CI): 1.16-1.35) and with a 39% increase in risk for mortality from all cancers (HR: 1.39, 95% CI: 1.23-1.57). The relationship between serum iron and cancer risk was a J-shaped one, with higher cancer risk at both ends, either at lower than 60 ?g/dL or higher than 120 ?g/dL. At higher end, cancer risk increased by 4% for every 10 ?g/dL increment above 80 ?g/dL, showing a dose response relationship, with 60-79 ?g/dL as a reference level. In a sensitivity analysis, the increases in risk were still observed after the first five years of cancer cases were excluded. Liver cancer risk was increased in HBV (-) subjects (3-fold) and HBV (+) subjects (24-fold). Lifestyle risks such as smoking, drinking or inactivity interacted synergistically with high serum iron and significantly increased the cancer risks. The risk remained elevated after first 5 years of observation. The liver (HR: 2.98, 95% CI: 2.32-3.84) and the breast (HR: 1.31, 95% CI: 1.01-1.70) were the two major cancer sites where significant cancer risks were observed for serum iron ?140 ?g/dL. The authors concluded that the findings reveal that high serum iron is both a common disorder and a marker of increased risk for several cancers

Authors: Wen CP, Lee JH, Tai YP, Wen C, Wu SB, Tsai MK, Hsieh DP, Chiang HC, Hsiung CA, Hsu CY, Wu X. ;Full Source: Cancer Research. 2014 Sep 16. pii: canres.0360.2014. [Epub ahead of print] ;