Effects of Trace Elements on Anthropometric Characteristics of Children: Cobalt and Childhood Body Mass Index.

OBJECTIVES

There are many reports on the effects of trace elements on human anthropometric characteristics. Among these elements, cobalt has consistently shown an inverse relationship with obesity risk. In the present study, we aimed to investigate the relationship between urinary levels of trace elements, focusing on cobalt, and childhood obesity, as indicated by the body mass index (BMI) in early adolescents, focusing on the participants' gender.

DESIGN

A cross-sectional study was conducted in the Tokyo Teen Cohort study. Based on urinary samples, we obtained the anthropometric characteristics (weight and height) and potential covariates associated with childhood BMI for 1542 children (mean age=12 years; 860 boys and 682 girls).

METHODS

Concentrations of urinary cobalt and 17 other trace elements were measured using inductively coupled plasma-mass spectrometry or inductively coupled plasma-atomic emission spectrometry.

RESULTS

Pearson's correlation coefficient revealed an inverse relationship between the log of cobalt concentrations in the urine and the BMI for the boys (r=-0.125, p<0.001) and girls (r=-0.082, p=0.033). Multivariate analysis, adjusted for various covariates, reconfirmed the correlation between urine cobalt and the childhood BMI, only in the boys (beta=-0.14, p<0.001).

CONCLUSIONS

Among the 18 elements measured in the children's urine, cobalt may exhibit sufficient potency to decrease the risk of childhood obesity, particularly in boys. Future studies are required to clearly determine the magnitude of the effect and the underlying mechanism(s).