Toenail and Serum Measures as Biomarkers of Iron Levels

32 Pages Posted: 16 Feb 2022

See all articles by Ann Von Holle

Ann Von Holle

affiliation not provided to SSRN

Katie M. O'Brien

National Health Research Institutes - National Institute of Environmental Health Sciences

Dale P. Sandler

National Health Research Institutes - National Institute of Environmental Health Sciences

Robert Janicek

affiliation not provided to SSRN

Margaret R. Karagas

Geisel School of Medicine at Dartmouth - Department of Epidemiology

White J. Alexandra

National Health Research Institutes - National Institute of Environmental Health Sciences

Nicole M. Niehoff

National Health Research Institutes - National Institute of Environmental Health Sciences

Levine E. Keith

RTI International

Brian P. Jackson

Dartmouth College

Clarice R. Weinberg

National Health Research Institutes - National Institute of Environmental Health Sciences

Abstract

BackgroundSerum iron is often assessed in epidemiologic studies, both as an exposure associated with diseases such as cancer and as an outcome indicating iron deficiency or overload. Toenails offer a convenient alternative to serum because of ease of collection, transport, and storage. Very few contemporary studies have examined the correlation between serum and toenail measures for trace metals.AimOur aim was to compare iron measures using serum and toenails on both a cross-sectional and longitudinal basis.MethodsUsing a subset of the US-wide prospective Sister Study cohort, we compared iron levels in toenails with three common serum biomarkers: iron, ferritin and percent transferrin saturation.ResultsAmong 146 participants who donated both blood and toenails at baseline, a subsample (59%) again provided specimens of both about 8 years later. Cross-sectional analyses included Spearman’s rank correlations between toenail and serum levels. We also considered maintenance of rank across time separately for toenails and for the serum measures. Overall, toenail values were not correlated with serum iron measures. Spearman correlations at baseline (follow-up) were 0.08 (0.09) for serum iron, 0.08 (0.07) for transferrin saturation, and -0.09 (-0.17) for ferritin. The Spearman correlation for toenail iron between the two time points was higher (0.47, 95% CI: 0.30, 0.64) than for serum iron (0.30, 95% CI: 0.09, 0.51) and transferrin saturation (0.34, 95% CI: 0.15, 0.54), but lower than that for ferritin (0.58, 95% CI: 0.43, 0.73).ConclusionBased on cross-sectional and repeated assessments, our evidence does not support an association between serum and toenail iron measures. Toenail iron measures did appear to be moderately repeatable but cannot be taken as a proxy for serum iron values and those exposure biomarkers may represent different compartments of iron storage.

Keywords: toenails, nails, iron, serum, comparisons

Suggested Citation

Von Holle, Ann and O'Brien, Katie M. and Sandler, Dale P. and Janicek, Robert and Karagas, Margaret R. and Alexandra, White J. and Niehoff, Nicole M. and Keith, Levine E. and Jackson, Brian P. and Weinberg, Clarice R., Toenail and Serum Measures as Biomarkers of Iron Levels. Available at SSRN: https://ssrn.com/abstract=4035544 or http://dx.doi.org/10.2139/ssrn.4035544

Ann Von Holle

affiliation not provided to SSRN ( email )

No Address Available

Katie M. O'Brien

National Health Research Institutes - National Institute of Environmental Health Sciences ( email )

Miaoli
Taiwan

Dale P. Sandler

National Health Research Institutes - National Institute of Environmental Health Sciences ( email )

Robert Janicek

affiliation not provided to SSRN ( email )

No Address Available

Margaret R. Karagas

Geisel School of Medicine at Dartmouth - Department of Epidemiology

Hanover, NH 03755
United States

White J. Alexandra

National Health Research Institutes - National Institute of Environmental Health Sciences ( email )

Miaoli
Taiwan

Nicole M. Niehoff

National Health Research Institutes - National Institute of Environmental Health Sciences ( email )

Miaoli
Taiwan

Levine E. Keith

RTI International ( email )

PO Box 12194
Washington, DC 20036-3209
United States

Brian P. Jackson

Dartmouth College ( email )

Department of Sociology
Hanover, NH 03755
United States

Clarice R. Weinberg (Contact Author)

National Health Research Institutes - National Institute of Environmental Health Sciences ( email )

Miaoli
Taiwan

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