Toenail trace element status and risk of Barrett's oesophagus and oesophageal adenocarcinoma: Results from the FINBAR study

Abstract

Trace elements have been cited as both inhibitory and causative agents of cancer but importantly exposure to them is potentially modifiable. This study aimed to examine toenail trace element status and risk of Barrett’s oesophagus (BO) and oesophageal adenocarcinoma (OAC). Toenail clippings from each hallux were obtained from 638 participants of the FINBAR study (Factors Influencing the Barrett’s Adenocarcinoma Relationship) comprising 221 healthy controls, 98 reflux oesophagitis, 182 BO and 137 OAC cases. The concentrations of eight toenail trace elements were determined using Instrumental Neutron Activation Analysis. Using multivariable adjusted logistic regression analysis, odds ratios (OR) and 95% CIs were calculated within tertiles of trace element concentrations. A two-fold increased risk of BO was observed, but not OAC, amongst individuals in the highest tertile of toenail zinc status OR 2.21 (95% CI 1.11–4.40). A higher toenail selenium status was not associated with risk of OAC OR 0.94 (95% CI 0.44–2.04) or BO OR 0.89 (95% CI 0.37–2.12). A borderline significant increased risk of BO was detected with a higher toenail cobalt concentration, OR 1.97 (95% CI 1.01–3.85). No association was found between toenail levels of chromium, cerium, mercury and OAC or BO risk. This is the first case-control study to investigate a variety of trace elements in relation to OAC and BO risk. Despite antioxidant and proapoptotic properties, no associations were found with selenium. Higher concentrations of toenail zinc and cobalt were associated with an increased BO risk, but not OAC. These findings need confirmation in prospective analysis.

Toenail mineral concentration and risk of esophageal squamous cell carcinoma, results from the Golestan Cohort Study

“…Few other studies have measured chromium in toenails. The concentration of chromium in our study (0.71 μ g/g) was more than that reported in the FINBAR study conducted in Ireland (0.55 μ g/g) . Surprisingly, we also found an inverse association between toenail chromium concentration and risk of ESCC.…”

“…We caution that the observed association is based on small case numbers. Also of note, the mean concentration of mercury among controls in this study was very low (0.04 ± 0.05 μ g/g) compared to those reported in the Nurse's Health Study (0.33 ± 0.63 μ g/g) and the Health Professionals Follow‐up Study (excluding dentists) (0.44 ± 0.47 μ g/g) in the US and the FINBAR case‐control study (0.11 ± 0.23 μ g/g) in Ireland .…”

Placental Metal Concentrations in Relation to Maternal and Infant Toenails in a U.S. Cohort

“…Quantification of elements in human finger- and toenails is an established biomarker for numerous essential and non-essential elements with and without known biological functions (53). Nails have been used previously as a biomarker for exposure to Hg (38, 54–57), Mn (58), Se (57) and Zn (59, 60). Fewer studies have used nails as biomarkers of Cd and Pb, and for Pb have observed correlations with blood Pb concentrations, and with exposure (38).…”

Dietary Risk Reduction Factors for the Barrett’s Esophagus-Esophageal Adenocarcinoma Continuum: A Review of the Recent Literature

“…Two case-control studies from Australia [28•] and Ireland [33] reported a 15-20% increased risk associated with selenium intake. However, results differed when toenail selenium concentrations were examined; the Irish case-control study found no association [39], and a Dutch case-cohort study reported a 24% decreased risk [40]. In a cohort study of BE patients that examined EA-related outcomes, EA risk was increased 40% in association with higher serum selenium concentrations [41].…”

“…In contrast, three more recent case-control studies, conducted in Australia [28•], Ireland [33], and the U.S. [26••], found little or no association between selenium intake and BE. Toenail selenium levels were associated with modest 11% risk reductions in the Irish case-control study [39] and, among women only, in a Dutch case-cohort study [43]. …”