Table 2. Epidemiologic studies of arsenic exposure and electrocardiographic abnormalities.

Reference	Location	Study design	Study population	Arsenic measurement	Arsenic levels	Endpoints	Main findings
Wang et al.[62]	Southwestern Taiwan	Cross-sectional	280 men and 355 women	Well water	Median in villages: 700–930 μg/L	QTc prolongation	A dose-response relationship between three measures of arsenic exposure and the prevalence of QTc prolongation with adjustment for age, sex, hypertension, diabetes mellitus, serum total cholesterol and triglyceride level, BMI, cigarette smoking, and alcohol consumption.
Ahmad et al. [59]	Bangladesh	Cross-sectional	50 each in exposed with or without skin lesions and unexposed	Well water	100–800 μg/L in well water, mean 493 μg/L	QTc prolongation	Prevalence of QTc prolongation was significantly higher in arsenic-exposed group with skin lesions than in those without skin lesions or not exposed to arsenic.
Yildiz et al. [60]	Turkey	Cross-sectional	40 men each in exposed and unexposed	Well water	422–1,066 μg/L in villages, mean 659 μg/L	QTc	QTc was significantly higher in men exposed to arsenic compared with in those unexposed.
						QTD	QTD was significantly higher in men exposed to arsenic compared with in those unexposed. The proportion of men with a QTD > 50 ms was significantly higher in the exposed group than in the unexposed.
						TDR	TDR was significantly higher in men exposed to arsenic compared with in those unexposed.
Mumford et al. [61]	Inner Mongolia	Cross-sectional	168 men and 145 women	Well water	≤ 21, 100–300, 430–690 μg/L in households	QTc prolongation	A significant monotonic relationship between well-water arsenic and the prevalence of QTc prolongation with adjustment for age, sex, BMI, and age/BMI interaction.
Mordukhovich et al. [63]	USA	Cross-sectional	226 elderly men	Toenail	Median in toenail: 0.069 μg/g, Interquartile range: 0.052–0.11 μg/g	QT and QTc	Toenail arsenic is positively associated with QT and QTc interval durations.
Chen et al. [64]	Bangladesh	Cross-sectional	1,715 adults	Well water, urine	0.1–790 μg/L in well water, mean 95 μg/L	QTc prolongation	A positive association between baseline arsenic exposure and the QTc prolongation assessed on average 6 years later. This association appeared to be present in women but not in men.
Wang et al. [65]	Southwestern Taiwan	Cross-sectional	280 men and 355 women	Well water	Median in villages: 700–930 μg/L	QTD	Cumulative arsenic exposure was dose-dependently associated with QTD with adjustment for age, sex, hypertension, diabetes mellitus, serum total cholesterol and triglyceride level, BMI, cigarette smoking, and habitual alcohol consumption.