Association between the urinary nickel and the diastolic blood pressure in general population

To investigate the association of the level of nickel and blood pressure (BP) level in a general population. A total of 2201 participants were enrolled from the National Health and Nutrition Examination Surveys (NHANES) 2017–2018. Urinary nickel level was measured using inductively coupled-plasma mass spectrometry. Multivariable linear regressions were performed to explore the associations between nickel and systolic BP and diastolic BP. Restricted cubic splines were used to explore the nonlinearity. Per one-fold increase of nickel was associated with a 0.67-unit decrease of diastolic BP (β −0.67, 95 % confidence interval [CI] [-1.15, −0.18]; p = 0.007). Comparing with the lowest quartile, the highest quartile decreased 2.21-unit diastolic BP (β −2.21, 95 % CI [-3.84, −0.59]; p = 0.007). Restricted cubic spline confirmed the relationship was linear. Subgroup analysis found that the association was only significant in population without hypertension. The urinary nickel, as a long-term exposure biomarker, was associated with the diastolic BP in individuals without hypertension.