title: Toenail selenium and risk of type 2 diabetes: the ORDET cohort study.
abstract: Epidemiologic studies, particularly randomized controlled trials, have shown a direct relation between dietary and environmental exposure to the metalloid selenium and risk of type 2 diabetes. We investigated the association between baseline toenail selenium levels and diabetes occurrence in a case-control study nested in ORDET, a population-based female cohort in Northern Italy. After a median follow-up of 16 years, we identified 226 cases of type 2 diabetes cases and 395 age-matched control women with available toenail samples at baseline. The multivariate odds ratios of diabetes in increasing a priori defined categories of toenail selenium exposure were 1.09 (95% confidence interval 0.61, 1.96), 0.71 (0.38, 1.34) and 1.14 (0.46, 2.80) compared with the lowest category. The results were not substantially altered when quartile distribution of toenail selenium in controls was used to define exposure categories. Spline regression analysis did not show homogeneous risk trends. Overall, we did not find an association between toenail selenium and subsequent development of diabetes. Since the diabetogenic activity of selenium is strongly supported by experimental studies and some observational investigations, our null results might be explained by the limitations of overall selenium toenail content to assess environmental exposure to selenium species of etiologic relevance in the study population.
authors.affiliation: Centro di Ricerca in Epidemiologia Ambientale, Genetica e Nutrizionale (CREAGEN), University of Modena and Reggio Emilia, Modena, Via Campi, 287, 41125 Modena, Italy. Electronic address: marco.vinceti@unimore.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Vinceti
authors.affiliation: Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, 20133 Milano, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Grioni
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
authors.forename: Dorothea
authors.initials: D
authors.lastname: Alber
authors.affiliation: Epidemiology Unit, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, Via San Barnaba, 8, 20122 Milan, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Consonni
authors.affiliation: Centro di Ricerca in Epidemiologia Ambientale, Genetica e Nutrizionale (CREAGEN), University of Modena and Reggio Emilia, Modena, Via Campi, 287, 41125 Modena, Italy.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Malagoli
authors.affiliation: Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, 20133 Milano, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Agnoli
authors.affiliation: Centro di Ricerca in Epidemiologia Ambientale, Genetica e Nutrizionale (CREAGEN), University of Modena and Reggio Emilia, Modena, Via Campi, 287, 41125 Modena, Italy.
authors.forename: Marcella
authors.initials: M
authors.lastname: Malavolti
authors.affiliation: Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, 20133 Milano, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Pala
authors.affiliation: Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, 20133 Milano, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Krogh
authors.affiliation: Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, 20133 Milano, Italy.
authors.forename: Sabina
authors.initials: S
authors.lastname: Sieri
mesh_terms: D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D016001:Confidence Intervals; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008875:Middle Aged; D009262:Nails / Q000378:metabolism*; D016017:Odds Ratio; D012044:Regression Analysis; D012307:Risk Factors; D012643:Selenium / Q000378:metabolism*; D018709:Statistics, Nonparametric; D014034:Toes / Q000502:physiology*
chemical_list: D012643:Selenium
keywords: Cohort study; Diabetes; Risk assessment; Selenium; Toenails