Transferrin Saturation, Dietary Iron Intake, and Risk of Cancer

Arch G. Mainous; James M. Gill; Charles J. Everett

doi:10.1370/afm.283

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Figure 1.
Population percentage cancer-free for normal vs elevated transferrin saturation (TS) >45% and low vs high iron (Fe) intake.

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Table 1.

Population Characteristics of Adults Aged 25 Years and Older From the NHANES I and NHEFS Studies With Normal (≤45%) or Increased (>45%) Transferrin Saturation (TS) Levels and Low (≤18 mg) or High (>18 mg) Iron Uptake Levels

Variable	Normal TS, Low Iron Intake n = 48,398,797	Normal TS, High Iron Intake n = 9,720,794	Increased TS, Low Iron Intake n = 3,994,430	Increased TS, High Iron Intake n = 606,162
NHANES = National Health and Nutrition Examination Survey; NHEFS = NHANES I Epidemiologic Follow-Up Study.
Age, y
25–34	22.07	34.63	23.63	37.23
35–44	20.99	25.05	19.87	21.18
45–54	23.47	20.26	25.71	26.67
55–64	20.90	14.18	19.14	7.37
>64	12.58	5.89	11.65	7.54
Sex
Male	39.88	79.02	45.61	75.42
Female	60.12	20.98	54.39	24.58
Race
White	90.35	91.58	94.46	93.58
Black	8.94	7.60	4.23	6.42
Other	0.71	0.82	1.31	0
Ever smoker
Yes	60.70	76.21	66.21	87.39
No	39.30	23.79	33.79	12.61
Body mass index, kg/m²
<30	83.00	85.27	90.01	99.56
≥30	17.00	14.73	9.99	0.44

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Table 2.

Survival Analysis of Cancer Events by Increased Serum Transferrin Saturation (>45%) and Levels of Iron Intake

Models	Hazard Ratio	95% CI
CI = confidence interval; TS = transferrin saturation.
* Adjusted for age, sex, race, smoking status, body mass index, and Charlson Comorbidity Index.
Model 1 (unadjusted)
Normal TS, low iron intake	1.00	1.00–1.00
Normal TS, high iron intake	0.75	0.55–1.01
Increased TS, low iron intake	1.02	0.69–1.49
Increased TS, high iron intake	1.74	0.78–3.85
Model 2 (adjusted)*
Normal TS, low iron intake	1.00	1.00–1.00
Normal TS, high iron intake	0.90	0.66–1.23
Increased TS, low iron intake	1.02	0.69–1.49
Increased TS, high iron intake	2.24	1.02–4.89

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The Article in Brief

In this study, the risk of developing cancer was increased in people with high levels of serum transferrin saturation, an indicator in those whose diets were high in iron intake (more than 18 mg of iron per day). No increased risk of cancer was found among those with high transferrin saturation whose diets were not high in iron. Simple dietary restrictions may help to reduce the cancer risk associated with high transferrin saturation.