Reproducibility of essential elements chromium, manganese, iron, zinc and selenium in spot samples, first-morning voids and 24-h collections from healthy adult men

Abstract

Evaluation of Cr, Mn, Fe, Zn and Se in humans is challenged by the potentially high within-individual variability of these elements in biological specimens, which are poorly characterised. This study aimed to evaluate their within-day, between-day and between-month variability in spot samples, first-morning voids and 24-h collections. A total of 529 spot urine samples (including eighty-eight first-morning voids and 24-h collections) were collected from eleven Chinese adult men on days 0, 1, 2, 3, 4, 30, 60 and 90 and analysed for these five elements using inductively coupled plasma-MS. Intraclass correlation coefficients (ICC) were utilised to characterise the reproducibility, and their sensitivity and specificity were analysed to assess how well a single measurement classified individuals’ 3-month average exposures. Serial measurements of Zn in spot samples exhibited fair to good reproducibility (creatinine-adjusted ICC = 0·47) over five consecutive days, which became poor when the samples were gathered months apart (creatinine-adjusted ICC = 0·33). The reproducibility of Cr, Mn, Fe and Se in spot samples was poor over periods ranging from days to months (creatinine-adjusted ICC = 0·01–0·12). Two spot samples were sufficient for classifying 60 % of the men who truly had the highest (top 33 %) 3-month average Zn concentrations; for Cr, Mn, Fe and Se, however, at least three specimens were required to achieve similar sensitivities. In conclusion, urinary Cr, Mn, Fe, Zn and Se concentrations showed a strong within-individual variability, and a single measurement is not enough to efficiently characterise individuals’ long-term exposures.

Seminal plasma selenium concentrations, sperm mtDNAcn, and semen quality: association and mediation analyses among healthy Chinese men

“…Substantial studies have also reported considerable high within-individual variabilities in sperm quality parameters [12][13][14][15] and Se concentrations in urine samples. 10,11 All these findings emphasize the importance of collecting repeated samples in the future studies.…”

“…Meanwhile, a lack of association between Se status and human semen quality was also reported. 8,9 These previous studies mostly relied on a single measurement of Se concentrations and semen quality, which is prone to measurement error, given the considerable high within-individual variabilities in urinary Se concentrations 10,11 and sperm quality parameters. [12][13][14][15] More importantly, little is known about the mechanisms underlying the associations between Se status and semen quality, which are critical to improve insights for disease development and prevention.…”

Novel Strategies for Assessing Associations Between Selenium Biomarkers and Cardiometabolic Risk Factors: Concentration, Visit-to-Visit Variability, or Individual Mean? Evidence From a Repeated-Measures Study of Older Adults With High Selenium

“…Because the collection of blood samples is invasive, the reproducibility of whole blood selenium measurement has rarely been studied. A longitudinal analysis of urine samples collected from 11 Chinese men at days 0, 1, 2, 3, 4, 30, 60, and 90 suggested poor reproducibility of urinary selenium (ICC = 0.03) ( 84 ). The reproducibility of whole blood and urinary selenium measurements may be affected by the kinetics of selenium absorption, distribution, metabolism, and elimination ( 85 ).…”

Magnetic levitation photothermal actuator with sunlight traction

“…The PG sheet moved in the direction of the sunlight and had a short response time, which was mainly related to its strong diamagnetic performance. Abnormal diamagnetic materials such as bismuth [29] and graphite [30] have larger magnetic susceptibility (χ) (up to 10 −4 -10 −3 ), and change rapidly with the increase of temperature. This made temperature a factor that can be used to manipulate the movement of PG sheet in a magnetic field.…”