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Arsenic exposure increases risk of left ventricular hypertrophy

Key clinical point: Native Americans exposed to arsenic may be at risk of left ventricular hypertrophy, and those with signs of prehypertension or hypertension may be at greater risk.

Major finding: The odds ratio of left ventricular hypertrophy per 100% increase in arsenic in the urine was 1.47 (95% confidence interval, 1.05-2.08) overall and 1.58 for individuals with prehypertension or hypertension (95% CI, 1.04-2.41).

Study details: An observational study of 1,337 Native Americans from the Strong Heart Family Study.

Disclosures: The Strong Heart Family Study was funded by the National Institute of Health Sciences and grants from the National Heart, Lung, and Blood Institute. The authors reported no relevant conflicts of interest.

Citation:

Pichler G et al. Circ Cardiovasc Imaging. 2019 May 1. doi: 10.1161/CIRCIMAGING.119.009018.

Commentary:

The results from Pichler et al. show the effects of recent arsenic exposure on left ventricular (LV) hypertrophy, but other questions remain as to the long-term effects of arsenic and its interactions with other environmental metals, Rajiv Chowdhury, MBBS, PhD, and Kim van Daalen, BSc, MPhil, wrote in a related editorial.

It has been established that chronic, low to moderate inorganic arsenic exposure may be linked to cardiovascular disease (CVD) and risk factors such as hypertension and diabetes, but it is unclear how different exposure pathways contribute as well as what pathophysiological mechanisms contribute to CVD, and whether arsenic directly or indirectly contributes to cardiac functioning or a worse cardiometabolic profile, respectively, they wrote.

While the results contribute to the understanding of arsenic exposure through drinking water and its relationship to LV function and geometry, urinary arsenic reflects recent exposure and cannot measure arsenic exposure over a period of time. The study also does not account for an individual’s CVD risk or LV functioning/geometry with daily exposure to co-occurring environmental metals, particularly heavy metals, together with arsenic. Factors such as genetics, age, gender, and nutrition also impact an individual’s reaction to arsenic, and studies should be able to differentiate inorganic arsenic obtained from food and other sources.

While “this elegant analysis ... helps to clarify the observational associations of [arsenic] with LV geometry and function, it stimulates further complimentary work,” they wrote. “Such studies would be essential since CVD remains the single leading cause of adult premature death worldwide, and millions of individuals globally are exposed to arsenic and other metal contaminants.”

Dr. Chowdhury and Dr. Daalen are from the cardiovascular epidemiology unit in the department of public health and primary care at the University of Cambridge (England).