Uranium Exposure, Hypertension, and Blood Pressure in the Strong Heart Family Study

Uranium is common in drinking water, soil, and dust in American Indian communities. Hypertension is a cardiovascular risk factor affecting American Indians. We evaluated the association between uranium exposure and incident hypertension and changes in blood pressure among Strong Heart Family Study participants.

We included 1,453 participants ≥14 years with baseline visits in 1998-1999 or 2001-2003, and follow-up in 2001-2003 and/or 2006-2009. We estimated the association of urinary uranium with changes in systolic and diastolic blood pressure levels over time and hypertension incidence; we accounted for family clustering.

Median (IQR) baseline urinary uranium levels were 0.029 (0.013-0.059) μg/g creatinine; 17.4% (n = 253) of participants developed hypertension. In the comparison of the urinary uranium quartile 4 (highest concentration) and quartile 1 (lowest concentration), the multi-adjusted risk ratio (95% CI) of incident hypertension was 1.44 (1.04-1.99). The associations between urinary uranium with changes in systolic and diastolic blood pressure were null and nonlinear, respectively. Both associations were modified by study site, and diastolic blood pressure showed a positive association beyond 5 µg/g creatinine. The association between urinary uranium and change in systolic blood pressure was inverse in Arizona and Oklahoma, and positive in North Dakota/South Dakota at higher ends of the uranium distribution.

Findings suggest a higher risk for hypertension at uranium levels typical of the Southwest and Great Plains than at levels in other regions (<0.01 µg/g creatinine); the associations with changes in systolic and diastolic blood pressure levels were consistent with a positive association with higher uranium exposure. Prospective research is critical to characterize the cardiovascular effects of uranium and develop preventive strategies for US Indigenous communities disproportionately exposed.