Mercury exposure, serum antinuclear antibodies, and serum cytokine levels in the Long Island Study of Seafood Consumption

Abstract

Mercury (Hg) is a well-known neurotoxin, and has been more recently studied specifically as an immunotoxin. In experimental and a few epidemiologic studies, Hg has been associated with distinct cytokine profiles and antinuclear antibody (ANA) positivity, though patterns at lower levels of exposure, typical of seafood consumers with a western diet, are not well characterized.

Seafood consumers (n=287) recruited on Long Island, NY completed food frequency and health questionnaires and provided blood for analysis of Hg, poly-unsaturated fatty acids (omega-3 and omega-6 fatty acids), selenium (Se), ANA, and several cytokines (IL-1 beta, IL-4, IL-10, TNF-alpha, IL-17, IFN-gamma, and IL-lra). Logistic and linear regression analyses were conducted to evaluate associations between serum Hg and cytokines and ANA. Adjusted models accounted for gender, age, ethnicity, income, education, smoking, BMI, selenium, omega 3 fatty acids, omega-6 fatty acids, omega-6/omega-3 ratio, and fish intake. Sex-stratified models were also generated with the expectation that immune profiles would differ between women and men.

Median blood Hg was 4.58 mu g/L with 90th %ile =19.8 mu g/L. Nine individuals displayed ANA positivity at serum titers above 1:80; many of the cytokines were below detection limits, and the ability to detect was used in the logistic regression analyses. In linear and logistic regression analyses, Hg was not significantly associated with any of the seven investigated cytokines or with ANA-positivity. Therefore, Hg was not associated with altered immune profiles in this population of seafood consumers.