TRANSFERRIN SATURATION AND RISK OF CANCER

The authors examined the hypothesis that relatively high levels of tra nsferrin saturation increase the risk of cancer. They studied a cohort of prepaid health plan members whose transferrin saturation levels we re measured during the period 1969-1971 and who were followed for canc er through 1990, After the exclusion of 10 percent of the subjects who received treatment for one or more of six chronic conditions or who w ere pregnant when the measurement was made and persons who contributed less than 5 years of follow-up, the authors were left with 38,538 per sons who were followed for an average period of 17,7 years, In women, a positive association was observed between transferrin saturation and risk of stomach carcinoma (greater than or equal to 34.5% compared wi th less than or equal to 20.3%: relative risk (RR) = 3.5, 95% confiden ce interval (Cl) 0.98-12), In men, transferrin saturation was inversel y associated with risk of colon and rectal carcinoma (greater than or equal to 40.7% compared with less than or equal to 26.0%: colon, RR = 0.62, 95% Cl 0.35-1.1; rectum, RR = 0.30, 95% Cl 0.08-1.1) and with no n-Hodgkin's lymphoma (32.1-40.6% compared with less than or equal to 2 6.0%: RR = 0.31, 95% Cl 0.11-0.88; no cases observed with transferrin saturation greater than or equal to 40.7%). The authors did not find e vidence that the risk of epithelial cancer (all sites combined) was re lated to transferrin saturation level or to iron deficiency (less than or equal to 15%) or overload (greater than or equal to 60%).