Serum Zinc Concentration in Children with Febrile Seizures: A Prospective Case Control Study

Abstract

Objective: To compare serum zinc concentrations between children with febrile seizures and age- and nutrition-matched febrile and afebrile controls, and to quantify the association between hypozincaemia and febrile seizures. Methods: In a prospective case-control study at a tertiary care teaching hospital in southern India, 200 consecutive children aged 6 to 60 months admitted with a seizure during a febrile illness, without evidence of central nervous system infection or other defined cause, were enrolled as cases. Two hundred controls matched for age band and nutritional status were enrolled concurrently: 100 febrile children without seizures and 100 afebrile children. Serum zinc was estimated colorimetrically within 24 hours of the seizure; hypozincaemia was defined as a concentration below 60 µg/dL. Results: Mean serum zinc was 59.4 (SD 16.8) µg/dL in cases, 82.4 (24.7) µg/dL in febrile controls and 84.0 (28.5) µg/dL in afebrile controls (F = 57.2, p < 0.001). Cases differed from febrile controls (mean difference −23.0 µg/dL, 95% CI −28.3 to −17.6) and from afebrile controls (−24.6 µg/dL, 95% CI −30.7 to −18.6), both p < 0.001, whereas the two control groups did not differ (p = 0.66). Hypozincaemia was present in 133 of 200 cases (66.5%) and 33 of 200 controls (16.5%), odds ratio 10.1 (95% CI 6.3 to 16.2; p < 0.001). Conclusions: Serum zinc was substantially lower in children with febrile seizures than in febrile or afebrile controls, and the deficit was not attributable to fever alone. Hypozincaemia may be a modifiable correlate of febrile seizure susceptibility, and randomised trials of zinc supplementation to prevent recurrence are warranted.

Keywords: Febrile seizures; Zinc; Hypozincaemia; Trace elements; Child, preschool; Case-control studies