Blood pressure hyperreactivity

Abstract

Essential hypertension is associated with chronic exposure to high levels of inorganic arsenic in drinking water. However, early signs of risk for developing hypertension remain unclear in people exposed to chronic low-to-moderate inorganic arsenic. Objective We evaluated cardiovascular stress reactivity and recovery in healthy, normotensive, middle-aged men living in an arsenic-endemic region of Romania. Methods Unexposed (n=16) and exposed (n=19) participants were sampled from communities based on WHO limits for inorganic arsenic in drinking water (<10 μg/l). Water sources and urine samples were collected and analyzed for inorganic arsenic and its metabolites. Functional evaluation of blood pressure included clinical, anticipatory, cold pressor test, and recovery measurements. Results Blood pressure hyperreactivity was defined as a combined stress-induced change in SBP (>20 mmHg) and DBP (>15 mmHg). Drinking water inorganic arsenic averaged 40.2±30.4 and 1.0±0.2 μg/l for the exposed and unexposed groups, respectively (P<0.001). Compared to the unexposed group, the exposed group expressed a greater probability of blood pressure hyperreactivity to both anticipatory stress (47.4 vs. 12.5%; P=0.035) and cold stress (73.7 vs. 37.5%; P=0.044). Moreover, the exposed group exhibited attenuated blood pressure recovery from stress and a greater probability of persistent hypertensive responses (47.4 vs. 12.5%; P=0.035). Conclusions Inorganic arsenic exposure increased stress-induced blood pressure hyperreactivity and poor blood pressure recovery, including persistent hypertensive responses in otherwise healthy, clinically normotensive men. Drinking water containing even low-to-moderate inorganic arsenic may act as a sympathetic nervous system trigger for hypertension risk.

Positive Association of Cardiovascular Disease (CVD) with Chronic Exposure to Drinking Water Arsenic (As) at Concentrations below the WHO Provisional Guideline Value: A Systematic Review and Meta-analysis

“…In this analysis, we assumed both a constant log-linear (log-transformed water As concentration) and a flexible non-linear (restricted cubic splines with knots at the 10th, 50th and 90th percentiles of log-transformed water As concentration) associations. The median value was assigned as the concentration level for each concentration category and if the median value was not provided directly, the mean or the midpoint values were calculated instead [16,25,45,59,63,[66][67][68][69][70][71][72][73][74][75]. For the calculation of the midpoint value for each concentration category, zero was used as the minimum if not available [16,25,66,[68][69][70][71][72][73].…”

“…The median value was assigned as the concentration level for each concentration category and if the median value was not provided directly, the mean or the midpoint values were calculated instead [16,25,45,59,63,[66][67][68][69][70][71][72][73][74][75]. For the calculation of the midpoint value for each concentration category, zero was used as the minimum if not available [16,25,66,[68][69][70][71][72][73]. Furthermore, without available maxima values, the width of the highest concentration category was assumed to be equal to the next lowest category [16,25,66,[68][69][70][71][72][73].…”

“…Unfortunately, evidence for low concentration effects, especially below the WHO permissible limit (10 µg/L) has been controversial and inconsistent [23,24]. For example, a cross-sectional study conducted by Kunrath et al [25] found an association between CVD risks and low-level As exposure, while other studies such as that of Jones, et al [26] for hypertension and that of Monrad et al [27] for myocardial infarction did not find similar associations. Such inconsistency might be related to limitations with sample size, exposure and outcome assessment as well as insufficient information on different CVD risk factors [26,28,29].…”

Relation of dietary inorganic arsenic to serum matrix metalloproteinase-9 (MMP-9) at different threshold concentrations of tap water arsenic

“…Chronic exposure to inorganic As (iAs) is associated with skin, bladder, lung and other cancers, 1–3 chronic lung problems 4–7 and cardiovascular disease and mortality. 8,9 These effects are generally associated with groundwater As concentrations greater than 50 or 100 μ g/l, though emerging research is beginning to identify elevated odds of skin lesions, 10,11 cancer, 12 respiratory infections and symptoms, 13,14 blood pressure effects, 15 and mortality from cardiovascular and other chronic diseases 9,16,17 from drinking water concentrations below 50 μ g/l.…”

A pilot study of low-moderate drinking water arsenic contamination and chronic diseases among reproductive age women in Timiş County, Romania

“…Another recent U.S. study reported higher odds for hypothyroidism among Hispanics with exposure to 8-22 μg/L drinking water iAs in Texas (OR=2.00, 95%CI 1.06-3.76; p=0.032), which the authors attributed in part to residential location (Gong et al, 2015). A study of low to moderate drinking water iAs exposures in nearby Arad County, Romania demonstrated a positive association with male blood pressure reactivity, an early indicator for hypertension and cardiovascular disease (Kunrath et al, 2013). …”