Abstract Body: Background:

Arsenic (As) is a leading environmental toxicant contributing to the global burden of hypertension and cardiovascular disease. Multiple studies have reported greater burden of hypertension among people of African ancestry including in the Caribbean although the mechanisms remain largely unexplored.

Hypothesis:

We investigated the hypothesis that environmental factors, such as arsenic exposure, are associated with greater risk of hypertension & high blood pressures in 965 middle aged and older (age range 40-87) Afro-Caribbean men and women from the Tobago Health Study.

Methods:

Arsenic exposure was measured as the sum of inorganic and methylated As (ΣAs = inorganic As + dimethylarsinic acid + monomethylarsonic acid) in spot urine samples using Liquid Chromatography & Inductively Coupled Plasma Mass Spectrometry. We used multiple linear regression models to examine cross-sectional associations of urine ΣAs with systolic blood pressure, diastolic blood pressure, pulse pressure & mean arterial pressure. Logistic regression models were used to examine odds of hypertension (defined as systolic BP ≥140, diastolic BP ≥ 90, or use of antihypertensive medication). The models were adjusted for age, sex, waist circumference, urinary creatinine, physical activity, smoking & antihypertensive treatment. Additionally, we conducted sex-stratified analyses separately in men and women. We also compared these associations within ΣAs exposure quartiles. We tested for effect measure modification by sex and p-values for interaction were calculated with likelihood ratio test to determine how sex interacted with these associations.

Results:

Each standard deviation increase in ΣAs (16.9 ng/ml) was associated with 40% higher odds of hypertension in the total cohort (OR: 1.40, 95% CI: 1.11–1.81, p: 0.008) and 90% higher odds in women (OR: 1.90, 95% CI: 1.13–3.47, p: 0.027). People with the highest ΣAs exposure quartile had 1.9-fold (95% CI:1.16, 3.12, p: 0.011 in total cohort) & 4.3-fold (95% CI: 1.96, 9.82, p: <0.001 in women) higher odds of hypertension compared to those with the lowest quartile. Evidence of effect modification by sex was observed, between ΣAs and mean arterial pressure (p-interaction =0.015) where men had higher mean arterial pressure.


Conclusion:

These findings suggest that exposure to inorganic arsenic is cross-sectionally associated to a sex specific pattern of greater burden of hypertension and high blood pressure among Afro-Caribbean adults in Tobago.