The routine urine tests included urobilinogen, bilirubin (BIL), keto-bodies, blood, protein, nitrite, WBCs, glucose, specific gravity, pH and vitamin C. We also measured urine Mn levels.
Future studies are needed that compare Mn levels measured in noninvasive biomarkers such as hair and toenails collected early in life to Mn levels in dentin from shed teeth.
Serum insulin (Linco, St . Louis MO) and IGF1 (Diagnostics Systems Laboratories, Inc. Webster, TX) and leptin (R&D Systems, Minneapolis, MN) levels were measure by ELISA according to the manufacturer's instructions.
Se, zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) levels were measured by inductively coupled plasma mass spectrometry (ICP-MS).
Plasma insulin (Morinaga; Tokyo, Japan) and leptin (R & D systems; MN) levels were measured by ELISA according to the manufacturer's guidelines.
For the first time since the U.S. National Health and Nutrition Examination Survey (NHANES) program started in the seventies, blood Mn levels were measured in 2011 2012.
Whole blood Mn levels were measured in participants 1 year and older, using inductively coupled plasma mass spectrometry (ICP-MS).
Levels of Mn measured in tooth dentin offers a promising biomarker of early life exposure that may better reflect fetal Mn levels than a single measure of Mn in maternal blood and provides an integrated measure of exposure over time.
Table 2 shows the correlation between prenatal Mn levels in tooth dentin, tooth enamel, blood, and urine measured at different time points.
In addition, as we did not examine the association between umbilical cord blood Mn levels and birth weight, and maternal blood sampling during pregnancy was not measured.
