Assessment of hypertension association with arsenic exposure from food and drinking water in Bihar, India.

Epidemiological studies have associated chronic exposure to arsenic (As) from drinking water with increased risk of hypertension. However, evidence of an association between As exposure from food and hypertension risks is sparse. To quantify the association between daily As intake from both food (rice, wheat and potatoes) and drinking water (Aswater) along with total exposure (Astotal) and hypertension risks in a study population in Bihar, India, we conducted an individual level cross-sectional analysis between 2017 and 2019 involving 150 participants. Arsenic intake variables and three indicators of hypertension risks (general hypertension, low-density lipoprotein (LDL) and high-density lipoprotein (HDL)) were derived, and any relationship was quantified using a series of crude and multivariable log-linear or logistic regression models. The prevalence of general hypertension was 40% for the studied population. The median level of HDL was 45 mg/dL while median value of LDL was 114 mg/dL. Apart from a marginally significant positive relationship between As intake from rice and the changes of LDL (p-value = 0.032), no significant positive association between As intake and hypertension risks could be ascertained. In fact, Astotal was found to be associated with lower risks of general hypertension and higher levels of HDL (p-value = 0.020 and 0.010 respectively) whilst general hypertension was marginally associated with lower Aswater (p-value = 0.043). Due to limitations regarding study design and residual confounding, all observed marginal associations should be treated with caution.

Arsenic exposure from food exceeds that from drinking water in endemic area of Bihar, India.

Extensive evidence of elevated arsenic (As) in the food-chain, mainly rice, wheat and vegetables exists. Nevertheless, the importance of exposure from food towards total As exposure and associated health risks in areas with natural occurring As in drinking water is still often neglected, and accordingly mitigations are largely focused on drinking water only. In this study, the contribution of food over drinking water to overall As exposure was estimated for As exposed populations in Bihar, India. Increased lifetime cancer risk was predicted using probabilistic methods with input parameters based on detailed dietary assessment and estimation of As in drinking water, cooked rice, wheat flour and potato collected from 91 households covering 19 villages. Median total exposure was 0.83 µg/kgBW/day (5th and 95th percentiles were 0.21 and 11.1 µg/kgBW/day) and contribution of food (median = 49%) to overall exposure was almost equal to that from drinking water (median = 51%). More importantly and contrary to previous studies, food was found to contribute more than drinking water to As exposure, even when drinking water As was above the WHO provisional guide value of 10 µg/L. Median and 95th percentile excess lifetime cancer risks from food intake were 1.89 × 10-4 and 7.32 × 10-4 respectively when drinking water As was below 10 µg/L and 4.00 × 10-4 and 1.83 × 10-3 respectively when drinking water As was above 10 µg/L. Our results emphasise the importance of food related exposure in As-endemic areas, and, perhaps surprisingly, particularly in areas with high As concentrations in drinking water - this being partly ascribed to increases in food As due to cooking in high As water. These findings are timely to stress the importance of removing As from the food chain and not just drinking water in endemic areas.

Wheat is an emerging exposure route for arsenic in Bihar, India.

In arsenic (As) endemic areas of south-east Asia, where a subsistence rice-based diet is prevalent, As exposure from food is mainly focused on rice intake. However, consumption of wheat is substantial and increasing. We present a probabilistic assessment of increased cancer risk from wheat-based food intake in a study population of rural Bihar, India where As exposure is endemic. Total As in wheat grains (43.64 ±â€¯48.19 µg/kg, n = 72) collected from 77 households across 19 villages was found to be lower than reported As in wheat grains from other south-east Asian countries but higher than a previous study from Bihar. This is the first study where As concentration in wheat flour was used for risk estimation, bearing in mind that it was the flour obtained after indigenous household processing of the grains that was used for making the home-made bread (chapati) which contributed 95% of wheat intake for the studied population. Interestingly, while 78% of the surveyed participants (n = 154) consumed rice every day, chapati was consumed every day by 99.5% of the participants. In contrast to previous studies, where As concentration in wheat grains was found to be lower than the flour due to the removal of the bran on grinding, we did not find any appreciable lowering of arsenic in the wheat flour (49.80 ±â€¯74.08 µg/kg, n = 58), most likely due to external contamination during processing and grinding. Estimated gender adjusted excess lifetime cancer risk of 1.23 × 10-4 for the studied rural population of Bihar indicated risk higher than the 10-4-10-6 range, typically used by the USEPA as a threshold to guide regulatory values. Hence, our findings suggest As exposure from wheat-based food intake to be of concern not only in As endemic areas of rural Bihar but also in non-endemic areas with similar wheat-based diet due to public distribution of the wheat across India.