| Summary: | Objective. Several epidemiological studies have reported that high concentrations of
circulating ferritin, a marker of iron stores, are related to insulin resistance (IR); however,
questions remain regarding inconsistent data between Asian men and women and the
inadequate consideration of potential confounding effects on the relationship between
ferritin and IR. Our aim was to examine the relationship between serum ferritin
concentrations and IR markers in the Japanese population.
Materials/Methods. We analyzed data (n=493) from a cross-sectional survey conducted in
2009 among a Japanese working population aged 20–68 years. Fasting serum ferritin and
insulin levels and fasting plasma glucose levels were determined, and the homeostatic
model assessment of IR (HOMA-IR) was calculated. Multiple regression analysis was
performed with adjustments for demographic and lifestyle factors, body mass index and
serum C-reactive protein.
Results. Fasting insulin and HOMA-IR significantly increased with increasing levels of
serum ferritin after adjustment for covariates in men (P for trend=.005 and .001,
respectively). Compared with men in the lowest tertile of serum ferritin, those in the
highest tertile had a 24% higher HOMA-IR score. Additional data suggested a positive
association between iron intake and HOMA-IR (P for trend=.07) in men. Neither serum
ferritin nor iron intake was related to IR markers in women, even in postmenopausalwomen.
Conclusions. Serum ferritin concentrations were positively associated with fasting insulin
and HOMA-IR in men but not in women, suggesting an important role of iron storage in the
pathogenesis of IR in Japanese men.
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