Water@leeds, School of Geography, University of Leeds, Leeds LS2 9JT, United Kingdom.
School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, United Kingdom.
Environ Int. 2017 Feb;99:331-342. doi: 10.1016/j.envint.2016.12.018. Epub 2016 Dec 29.
Previous risk assessment studies have often utilised generic consumption or intake values when evaluating ingestion exposure pathways. If these values do not accurately reflect the country or scenario in question, the resulting risk assessment will not provide a meaningful representation of cancer risks in that particular country/scenario.
This study sought to determine water and food intake parameters for one region in South Asia, rural Pakistan, and assess the role population specific intake parameters play in cancer risk assessment.
A questionnaire was developed to collect data on sociodemographic features and 24-h water and food consumption patterns from a rural community. The impact of dietary differences on cancer susceptibility linked to arsenic exposure was evaluated by calculating cancer risks using the data collected in the current study against standard water and food intake levels for the USA, Europe and Asia. A probabilistic cancer risk was performed for each set of intake values of this study.
Average daily total water intake based on drinking direct plain water and indirect water from food and beverages was found to be 3.5Lday (95% CI: 3.38, 3.57) exceeding the US Environmental Protection Agency's default (2.5Lday) and World Health Organization's recommended intake value (2Lday). Average daily rice intake (469gday) was found to be lower than in India and Bangladesh whereas wheat intake (402gday) was higher than intake reported for USA, Europe and Asian sub-regions. Consequently, arsenic-associated cumulative cancer risks determined for daily water intake was found to be 17 chances in children of 3-6years (95% CI: 0.0014, 0.0017), 14 in children of age 6-16years (95% CI: 0.001, 0.0011) and 6 in adults of 16-67years (95% CI: 0.0006, 0.0006) in a population size of 10,000. This is higher than the risks estimated using the US Environmental Protection Agency and World Health Organization's default recommended water intake levels. Rice intake data showed early life cumulative cancer risks of 15 chances in 10,000 for children of 3-6years (95% CI: 0.0012, 0.0015), 14 in children of 6-16years (95% CI: 0.0011, 0.0014) and later life risk of 8 adults (95% CI: 0.0008, 0.0008) in a population of 10,000. This is lower than the cancer risks in countries with higher rice intake and elevated arsenic levels (Bangladesh and India). Cumulative cancer risk from arsenic exposure showed the relative risk contribution from total water to be 51%, from rice to be 44% and 5% from wheat intake.
The study demonstrates the need to use population specific dietary information for risk assessment and risk management studies. Probabilistic risk assessment concluded the importance of dietary intake in estimating cancer risk, along with arsenic concentrations in water or food and age of exposed rural population.
以往的风险评估研究在评估摄入暴露途径时，通常使用通用的消费或摄入量值。如果这些值不能准确反映所讨论的国家或情况，那么由此产生的风险评估将不能对该国/地区的癌症风险提供有意义的描述。
本研究旨在确定南亚一个地区（巴基斯坦农村地区）的水和食物摄入量参数，并评估特定人群的摄入量参数在癌症风险评估中的作用。
设计了一份问卷，收集农村社区的社会人口特征和 24 小时水和食物消费模式数据。通过使用当前研究中收集的数据计算与砷暴露相关的癌症易感性的癌症风险，评估饮食差异对癌症风险的影响。针对本研究的每种摄入量值进行了概率性癌症风险评估。
基于直接饮用普通水和间接从食物和饮料中摄入的水，发现每日总水摄入量为 3.5L/天（95%CI：3.38，3.57），超过了美国环境保护署的默认值（2.5L/天）和世界卫生组织的推荐摄入量（2L/天）。发现每日大米摄入量（469g/天）低于印度和孟加拉国，而小麦摄入量（402g/天）高于美国、欧洲和亚洲次区域的报告摄入量。因此，确定每日水摄入量与砷相关的累积癌症风险，对于 3-6 岁的儿童为 17 次机会（95%CI：0.0014，0.0017），6-16 岁的儿童为 14 次机会（95%CI：0.001，0.0011），16-67 岁的成年人为 6 次机会（95%CI：0.0006，0.0006），人群规模为 10000 人。这高于使用美国环境保护署和世界卫生组织的默认推荐水摄入量水平估计的风险。大米摄入量数据显示，3-6 岁儿童的早期生活累积癌症风险为 15 次机会（95%CI：0.0012，0.0015），6-16 岁儿童为 14 次机会（95%CI：0.0011，0.0014），而后期生活风险为 8 名成年人（95%CI：0.0008，0.0008），人群规模为 10000 人。这低于摄入大米量较高且砷含量较高的国家（孟加拉国和印度）的癌症风险。砷暴露引起的癌症风险显示，总水的相对风险贡献为 51%，来自大米的为 44%，来自小麦的为 5%。
该研究表明，需要使用特定人群的饮食信息进行风险评估和风险管理研究。概率风险评估得出结论，饮食摄入在估计癌症风险方面以及水或食物中的砷浓度和暴露于农村人口的年龄都很重要。
