AIMS: Many of the secondary effects of high levels of molybdenum (Mo) overlap with symptoms commonly seen in pediatric patients with chronic kidney disease (CKD). We measured plasma Mo levels and examined the relationship between Mo levels and kidney function.

MATERIALS AND METHODS: The study was carried out at the London Health Sciences Centre in London, Ontario, Canada with 36 children and adolescents 4 - 18 years of age with CKD. There were 1 - 6 trace element measurements (Mo and copper (Cu)) per patient. We studied the proportion of patients with abnormal trace element levels and the relationship between trace element levels and estimated glomerular filtration rate (eGFR), calculated using the Filler formula. Plasma Mo and Cu levels were measured using High Resolution Sector Field Inductively Coupled Mass Spectrometry. Anthropomorphic data and blood parameters were collected from our electronic chart program.

RESULTS: Median eGFR was 51 mL/min/1.73m2 (35, 75). Median Mo level was 2.00 µg/L (1.40, 2.88). 20 patients had at least one set of Mo levels above the published reference interval in either unit, and the results of 46% of the tests were above the interval. There was a strong negative correlation between the Mo levels and the eGFR (Spearman's r = -0.627, p < 0.0001).

CONCLUSIONS: Our study suggests that pediatric patients with CKD have elevated plasma levels of Mo, which may cause secondary effects commonly associated with CKD. The elevated Mo levels in our center's catchment area may cause an accumulation of this trace element in patients with impaired renal function.