Relationship Between Mercury in Blood and 24-h Ambulatory Blood Pressure in Greenlanders and Danes

Background Intake of mercury with food items from sea mammals and fish has been suggested to be involved in cardiovascular disease, but the relationship between mercury in blood and 24-h ambulatory blood pressure (BP) has never been studied. Methods We measured mercury in blood and 24-h BP in four groups of healthy subjects: group 1, Danes living in Denmark consuming European food; group 2, Greenlanders living in Denmark consuming European food; group 3, Greenlanders living in Greenland consuming European food; and group 4, Greenlanders living in Greenland consuming mainly traditional Greenlandic food. Results Mercury in blood was highest in Greenlanders and increased when they lived in Greenland and consumed traditional Greenlandic food (group 1: 2.2 μg/L (median), group 2: 4.8 μg/L, group 3: 10.8 μg/L, and group 4: 24.9 μg/L). The 24-h BP was the same in all three groups of Greenlanders. However, 24-h diastolic BP was lower among Greenlanders than Danes (71 v 76 mm Hg, P< .000) and 24-h pulse pressure was higher (54 v 50 mm Hg, P< .000). Mercury in blood was significantly and positively correlated to pulse pressure (ρ = 0.272, P< .01). Conclusions Pulse pressure was higher and diastolic BP was lower in Greenlanders than Danes. Pulse pressure increased with higher mercury content in the blood. Although genetic factors must be responsible to some extent for the difference in pulse pressure between Greenlanders and Danes, the present results seem to support the hypothesis that mercury intake from maritime food is involved in cardiovascular disease.