Biomaterial Database

Estimation of variation among individuals of biological half-time of cadmium calculated from accumulation data. 1995

M Sugita, and K Tsuchiya

Department of Environmental and Occupational Health, Toho University School of Medicine, Tokyo, Japan.

For heavy metals, many experimental studies using animals have revealed short biological half-times (BHTs) to be 1 year or less by administration of heavy metals. Tsuchiya and Sugita, however, devised an original method and first reported the possibility of a long BHT for cadmium (Cd) calculated from Cd accumulation in postmortem human organs and tissues by age using a nonlinear regression analysis employing a differential equation. According to their reports, the estimated values of Cd BHT were 12.1-22.7 years in the kidney. The estimated Cd BHTs are point estimators. The point estimator of Cd BHT has been used indiscriminately to derive safety levels for Cd in the air of work environments or foodstuffs in the general population without taking into consideration individual variation of Cd BHT. In the present study, the estimated variation among individuals of Cd BHT ranges from a few years to at least 100 years in the kidney. It is concluded that the estimated average BHT according to mathematical calculation should not be used indiscriminately to derive the safety level of cadmium exposure.

UI	MeSH Term	Description	Entries
D007223	Infant	A child between 1 and 23 months of age.	Infants
D007231	Infant, Newborn	An infant during the first 28 days after birth.	Neonate,Newborns,Infants, Newborn,Neonates,Newborn,Newborn Infant,Newborn Infants
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008297	Male		Males
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D012044	Regression Analysis	Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.	Regression Diagnostics,Statistical Regression,Analysis, Regression,Analyses, Regression,Diagnostics, Regression,Regression Analyses,Regression, Statistical,Regressions, Statistical,Statistical Regressions
D002104	Cadmium	An element with atomic symbol Cd, atomic number 48, and atomic weight 112.41. It is a metal and ingestion will lead to CADMIUM POISONING.
D002648	Child	A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL.	Children
D002675	Child, Preschool	A child between the ages of 2 and 5.	Children, Preschool,Preschool Child,Preschool Children