Nutritional disturbances are often seen in children with end-stage renal disease (ESRD), potentially affecting their growth and development. Some nutritional elements and electrolytes are part of routine monitoring in patients with chronic kidney disease (CKD) and in pediatric dialysis patients; however, there are no examinations of levels of trace elements until after significant complications and/or problems arise.
Pediatric patients on dialysis and patients with CKD are susceptible to micronutrient deficiency associated with anorexia, poor dietary intake, altered metabolism, and dialysate loss. Further, toxic levels of some trace elements such as lead can accumulate in patients with impaired kidney function due to insufficient elimination or impurities in the dialysate.
Trace elements, measured in micrograms per milliliter, include heavy metals such as cadmium, chromium, nickel, vanadium, copper, lead, manganese, selenium, and zinc. Results of previous studies in adult patients with chronic renal failure found alterations in the blood levels of various trace elements. However, there are few data available on the levels of trace elements in pediatric patients with CKD and pediatric patients on dialysis.
Mohammad Esmaeili, MD, and Forough Rakhshanizadeh, MD, conducted a study designed to assess the levels of copper, zinc, selenium, and lead in the serum of children with ESRD not yet being treated or who were on long-term hemodialysis or continuous ambulatory peritoneal dialysis (CAPD). Results of the study were reported in the Journal of Renal Nutrition [2019;29(1):48-54].
The cross-sectional case-control study utilized data collected between August 2013 and June 2015 from 200 children with ESRD treated at Dr. Sheikh Children’s Hospital, a referral hospital for the department of pediatric nephrology of Mashhad University of Medical Sciences in Iran. The four trace elements were measured in four groups of children: (1) group A, n=63, children with ESRD receiving regular hemodialysis treatments; (2) group B, n=45, children on CAPD; (3) group C, n=14, children treated by conservative management; and (4) group D, n=78, healthy children (control group). There were no significant differences among the four groups in demographic characteristics.
The mean serum levels of zinc and selenium were significantly lower in group A (hemodialysis) compared with group D (healthy controls), P<.001. Levels of lead were significantly higher in patients in group A than in the healthy controls, P<.001.
There were no significant differences in serum levels of zinc, selenium, and lead between group A and group B (CAPD); levels of zinc and selenium were significantly lower in patients in group A than in those in group C (conservative management). There were nonsignificant differences in serum levels of copper among the four groups. Levels of lead were significantly higher in group A compared with group C.
Serum levels of selenium and zinc were significantly lower in group B than in group C (P<.05) and the control group (P<.001). Levels of lead were significantly higher in group B than in group C (P<.001) and group D (P<.001). There were no significant differences between group C and group D in serum levels of zinc, selenium, and lead.
In citing limitations to the study, the researchers included the lack of a detailed nutritional assessment of the patients and evaluating the trace elements level during a limited period of time.
In summary, the researchers said, “We found that the serum levels of selenium, zinc, and lead were substantially different between the dialysis groups and the control group and the children with CKD. The results highlighted the role of osmosis during dialysis and dialysate impurities in causing disturbances of trace elements. The study also highlighted the role the kidney plays in the homeostasis of trace elements even with minimum residual function. Because a deficiency or an excess of trace elements can be harmful to health, especially in CKD children on dialysis (hemodialysis or CAPD), an understanding and routine assessment of the nonspecific features of subtle nutritional deficits should be performed by a skilled renal dietitian. The regular monitoring of trace elements in these patients once or twice a year is also advisable, as a deficiency or excess of trace elements is potentially amenable to therapy.”
Takeaway Points
- Trace elements are not routinely monitored in pediatric patients with chronic kidney disease (CKD). Researchers in Iran conducted a study to examine the serum levels of copper, zinc, selenium, and lead in children with end-stage renal disease.
- The four study groups were children on hemodialysis, children on peritoneal dialysis, children treated with conservative management, and a control group of healthy children.
- There were substantial differences in the levels of trace elements between the two dialysis groups and the conservative management group and the control group.
