Background: Selenium is an antioxidant micronutrient with potential interest for cardiovascular disease prevention. Few studies have evaluated the association between selenium and hypertension, with inconsistent findings. We explored the relationship of serum selenium concentrations with blood pressure and hypertension in a representative sample of the US population.
Methods and results: We undertook a cross-sectional analysis of 2638 adults > or =40 years old who participated in the 2003 to 2004 National Health and Nutrition Examination Survey. Serum selenium was measured by inductively coupled plasma-dynamic reaction cell-mass spectrometry. Hypertension was defined as blood pressure > or =140/90 mm Hg or current use of antihypertensive medication. Mean serum selenium was 137.1 microg/L. The multivariable adjusted differences (95% CIs) in blood pressure levels comparing the highest (> or =150 microg/L) to the lowest (<122 microg/L) quintile of serum selenium were 4.3 (1.3 to 7.4), 1.6 (-0.5 to 3.7), and 2.8 (0.8 to 4.7) mm Hg for systolic, diastolic, and pulse pressure, respectively. The corresponding odds ratio for hypertension was 1.73 (1.18 to 2.53). In spline regression models, blood pressure levels and the prevalence of hypertension increased with increasing selenium concentrations up to 160 microg/L.
Conclusions: High serum selenium concentrations were associated with higher prevalence of hypertension. These findings call for a thorough evaluation of the risks and benefits associated with high selenium status in the United States.