Written by Joyce Smith, BS. Consumption of fish contaminated with heavy metals during pregnancy may cause the immune systems of offspring to produce antinuclear antibodies and juvenile idiopathic arthritis.
Idiopathic juvenile arthritis (IJA) is a heterogeneous chronic childhood autoimmune disease of unknown etiology 1 that at times will demonstrate the presence of antinuclear antibodies (ANA). 2-4 There is no single blood test that diagnoses JIA, but rather a combination of several blood tests, history and physical exam are necessary for a definitive diagnosis of JIA. Researchers Kindred et al believed that increased knowledge of the role of early nutrition and its association with autoimmunity might provide answers to the cause of immune-mediated IJA. A previous study by the authors suggested that longer breast feeding may actually lower risk for JIA. 4 Using a population-based prospective birth cohort of 15,740 children from the All Babies in Southeast- Sweden Project (ABIS) and the Swedish pediatric JIA registry, Kindgren’s group 5 attempted to demonstrate an association between fish consumption during pregnancy and early childhood and the development of IJA. Sixteen years after the study began, they had identified 42 children with JIA, all of whom had completed questionnaires about diet, lifestyle, and environmental exposures. Biologic samples were obtained at birth and throughout childhood and when analyzed for the presence of ANA, 11 out of the 42 children were found to be ANA positive. The cord blood of these 42 patients with IJA, along with the cord blood of 40 age and sex-matched controls, was analyzed for the presence of four heavy metals: aluminum (Al), cadmium (Cd), mercury (Hg), and lithium (Li).
The Kindred group found that cord blood concentrations of Al, Cd, and Li were significantly higher in the ANA group (n=11) than in the controls. Also, among the 42 children with IJA, mean cord blood concentrations of heavy metals were significantly higher than among the controls:
- Aluminum: 11.2 vs 6.1 ug/L (p<0.001)
- Cadmium: 0.19vs0.07 ug/L (p<0.001
- Mercury: 0.33 vs. 0.24 ug/L (p<0.001)
- Lithium: 2.79 vs 1.01 ug/L (p<0.001)
Of interest was the fact that more than half of the IJA children had concentrations of these metals that were two standard deviation above the mean. However, cord blood concentrations of Al, Cd, and Li were also significantly higher among the children who were ANA positive, and almost two-thirds of these ANA positive IJA children had even higher metal concentrations (more than two standard deviations above the mean).
The frequency of maternal fish consumption during pregnancy correlated with concentrations of Ca, Hg and Li; the frequency of maternal fish consumption from the Baltic Sea correlated with concentrations of Cd; the consumption of fish from other oceans correlated with concentrations of Cd, Li, and Hg.
Study limitations included a patient sample of JIA too small (n=42) for subgroup analysis, unmeasured fish contaminants as well as confounders, misclassified diagnosis, selection bias and a lack of data generalization. Strengths were the prospective study design which avoided potential recall and selection biases that are common to retrospective studies, and the use of a Swedish pediatric JIA- register for data collection.
This study suggests that even moderate exposure to Al, Ca, Hg, and Li during pregnancy and early childhood may affect the immune system of offspring resulting in the development of ANAs and JIA. The content of heavy metals in foods should be included in future food and nutrition guidelines during pregnancy and infancy to help protect against the development of this chromic disease.
Source: Kindgren, Erik, Carlos Guerrero-Bosagna, and Johnny Ludvigsson. “Heavy metals in fish and its association with autoimmunity in the development of juvenile idiopathic arthritis: a prospective birth cohort study.” Pediatric Rheumatology 17, no. 1 (2019): 33.
© The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/) (http://creativecommons.org/publicdomain/zero/1.0/)
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Posted July 22, 2019.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- Petty RE, Southwood TR, Manners P, et al. International League of Associations for Rheumatology classification of juvenile idiopathic arthritis: second revision, Edmonton, 2001. The Journal of rheumatology. 2004;31(2):390.
- Guillaume S, Prieur AM, Coste J, Job‐Deslandre C. Long‐term outcome and prognosis in oligoarticular‐onset juvenile idiopathic arthritis. Arthritis & Rheumatism: Official Journal of the American College of Rheumatology. 2000;43(8):1858-1865.
- Al‐Matar MJ, Petty RE, Tucker LB, Malleson PN, Schroeder ML, Cabral DA. The early pattern of joint involvement predicts disease progression in children with oligoarticular (pauciarticular) juvenile rheumatoid arthritis. Arthritis & Rheumatism. 2002;46(10):2708-2715.
- Kindgren E, Fredrikson M, Ludvigsson J. Early feeding and risk of juvenile idiopathic arthritis: a case control study in a prospective birth cohort. Pediatric Rheumatology. 2017;15(1):46.
- Kindgren E, Guerrero-Bosagna C, Ludvigsson J. Heavy metals in fish and its association with autoimmunity in the development of juvenile idiopathic arthritis: a prospective birth cohort study. Pediatric Rheumatology. 2019;17(1):33.
