Blood bromine levels in a Pacific atoll population

Serum and red cells from 20 Marshallese on two atolls and from 10 subjects in New York were compared for their elemental composition employing an energy dispersive X-ray fluorescence technique. The elements analyzed in serum included Cl, Zn, and Br, whereas red cells were analyzed for Cl, K, Fe, Zn, Br, and Rb. Both Marshallese groups showed statistically significant (P less than 0.01) elevations in serum Br (51 and 96%) and in red cell Br (393 and 478%) as compared to the New York group. The Marshallese Br/Cl ratio in serum and in red cells was elevated when compared to that of the New York group, whereas the Rb/K ratios were equivalent. The red cell Br/serum Br ratio was also elevated in the Marshallese subjects. There were no similar differences noted among the other elements tested. Drinking liquids in the Marshall Islands were analyzed for Br but did not provide a clear source for the elevated Br levels.