中国膳食暴露评估非参数概率模型构建

目的 为提高评估精度并与国际食品安全风险评估技术接轨,构建中国膳食暴露评估非参数概率模型.方法 利用我国膳食调查、污染物监测数据及相应的人口学资料建立膳食消费量和化学污染物浓度经验分布.通过蒙特卡洛(Monte Carlo)模拟和自助法(Bootstrap)抽样获得人群膳食暴露变异度和不确定度.其中,膳食量数据和人口学数据来源于2002年中国居民营养与健康状况调查24 h膳食回顾法收集的22 567个家庭66 172人连续3 d调查共计193 814个人日、1 810 703条数据.污染物监测数据为2000-2006年全国14个省或地区食品污染物监测网以及2005-2006年海关出口农产品监测数据,包括重金属、农药,以及霉菌毒素(如黄曲霉毒素)等135种污染物,涉及499种食物,共计487 819条数据.结果 构建了包括重金属、农药及部分毒素的我国人群膳食暴露非参数概率评估模型,得到不同污染物膳食暴露量分布的指标统计量和95%可信区间.对7～10岁儿童乙酰甲胺磷膳食暴露评估显示,城乡儿童膳食暴露量的中位数分别为1.77μg·kg~(-1)·d~(-1)和2.48μg·kg~(-10·d~(-1),其95%可信区间分别为(1.59～2.06)μg·kg~(-1)·d~(-1)和(2.33～2.80)μg·kg~(-1)·d~(-1).结论 构建的非参数概率模型可量化暴露评估中的变异度和不确定度,提高了膳食暴露评估精度.     

化学污染物慢性膳食暴露评估全概率模型构建研究北大核心CSCD

目的提高食品安全风险评估精度,构建化学污染物慢性膳食暴露评估全概率模型。方法利用我国膳食调查、污染物监测数据以及相应的人口学资料构建膳食暴露评估全概率模型。通过在消费量和污染物总体中进行蒙特卡洛(Monte Carlo)抽样,匹配相乘后得到暴露量的概率分布;构建贝塔二项正态分布(Betabinomial and normal,BBN)模型,将横断面调查获得的短期暴露量近似"拉伸"为长期(慢性)暴露量;通过Monte Carlo模拟和自助法(Bootstrap)对人群膳食暴露量进行变异度和不确定度分析。结果以江苏省居民铅膳食暴露评估为例,构建了化学污染物慢性膳食暴露全概率评估模型。全概率模型和半概率模型比较显示:两种模型计算的暴露量均值接近,但全概率模型计算结果的变异度大于半概率模型,表现为其低端百分位数小于半概率模型,高端百分位数大于半概率模型。结论化学污染物慢性膳食暴露全概率模型评估结果较半概率模型保守。     

中国膳食暴露评估数据库食物分类及编码研究

目的 对膳食调查及污染物监测数据进行分类和编码,为构建中国膳食暴露评估数据库奠定基础.方法 采用国际食品法典委员会(Codex Alimentarius Commission,CAC)食品法典(CODEX)的食物分类与我国食物成分表食物分类原则相结合的方式,按照食物所属组别前2位英文字母代表该食物的种类或来源,后4位数字代表该食物在CAC食物分类系统中排列序号的方式,对我国1 810 703条膳食消费量和487 810条污染物监测数据进行分类和编码.凡在CAC食物编码中找到对应编码的,一律采用CAC编码,对CAC编码中没有的食物则按CAC编码原则新增编码.结果 我国膳食消费数据分为6个大类、19个种类、75个组别,污染物监测农产品对应499个编码;相比CAC编码系统新增F(糖果类小食品)与G(饮料)2个大类、4个种类、33个组别、302个编码.新增组别大多为罐头类、饮料类、糖果类、肉制品类等动植物类加工食物,新增食物类别和编码大多是具有中国特色的食物.结论 初步实现了中国食物分类和编码与CAC分类编码系统的接轨,为膳食暴露评估奠定了数据交流的基础.     

化学污染物慢性膳食暴露评估全概率模型构建研究

目的提高食品安全风险评估精度,构建化学污染物慢性膳食暴露评估全概率模型。方法利用我国膳食调查、污染物监测数据以及相应的人口学资料构建膳食暴露评估全概率模型。通过在消费量和污染物总体中进行蒙特卡洛(Monte Carlo)抽样,匹配相乘后得到暴露量的概率分布;构建贝塔二项正态分布(Betabinomial and normal,BBN)模型,将横断面调查获得的短期暴露量近似"拉伸"为长期(慢性)暴露量;通过Monte Carlo模拟和自助法(Bootstrap)对人群膳食暴露量进行变异度和不确定度分析。结果以江苏省居民铅膳食暴露评估为例,构建了化学污染物慢性膳食暴露全概率评估模型。全概率模型和半概率模型比较显示:两种模型计算的暴露量均值接近,但全概率模型计算结果的变异度大于半概率模型,表现为其低端百分位数小于半概率模型,高端百分位数大于半概率模型。结论化学污染物慢性膳食暴露全概率模型评估结果较半概率模型保守。     

两种模型在铅膳食长期暴露评估中的运用研究

目的 比较观测个体均值(observed individual means,OIM)模型与贝塔二项-正态分布(betabinomial-normal,BBN)模型结果及其在铅膳食长期暴露评估中的运用.方法 利用2002年中国居民营养与健康状况调查中24 h膳食回顾法收集的消费量数据、2000-2006年污染物监测数据及2005-2006年海关出口农产品监测数据.OIM模型通过计算调查期间个体食物的平均消费量与污染物平均浓度匹配相乘,计算每日暴露量,而BBN模型通过调整个体内变异,保留个体间变异构建长期膳食暴露量.以铅污染数据为实例,对两模型结果进行比较.结果 OIM模型高端百分位数值均大于BBN模型,OIM模型全人目第25～99.9百分位数(P25～P99 9)的摄入量为1.167 ～7.313 μg·kg-1·d-1,BBN为1.193 ～5.729 μg·kg-1·d-1.各组OIM模型与BBN模型结果中位数较为接近,两模型全人群摄入量分别为1.543和1.579 μg· kg-1·d-1.结论 在膳食长期暴露评估中,OIM模型分析结果比BBN模型在高端百分位数部分更具保守性.     

膳食暴露评估模型及其构建方法

膳食暴露评估是食品风险评估的重要组成部分，是对生物性、化学性与物理性因子通过食品或其他相关来源摄入量的定量或定性评估。其评价主要从观察个体消费量、食物污染物残留浓度数据等方面进行。笔者在给出膳食暴露评估确定性模型的基础上，重点介绍了新近出现的概率性模型的构建方法，以期为我国膳食暴露评估工作带来一些有益启示。     

中国膳食暴露评估模型软件开发及验证

目的 开发具有我国自主知识产权的膳食暴露评估模型软件,并按国际通用标准对其概率评估模型进行合理性和计算正确性验证.方法 基于我国膳食调查及食品污染物监测数据,采用统计分析系统(SAS)编程技术建立膳食暴露评估模型计算模块和人机对话界面.使用全国2～7岁儿童膳食暴露概率评估模型的结果与点估计及江苏省金湖地区2～7岁儿童双份饭研究结果相比较的方法验证模型的合理性.通过随机抽取10 000人天的膳食暴露数据与@Risk软件计算结果相比较的方法验证软件外部计算的正确性;以模型计算的2～3岁儿童食物消费量及铅污染残留浓度数据的均数漂移为指标验证本软件内部计算的正确性.结果 成功开发了包括多种膳食暴露评估模型并具有易于操作用户界面的中国膳食暴露评估模型软件.在合理性验证方面,概率评估模型结果低于点估计,其中黄瓜的乙酰甲胺磷膳食暴露点估计为4.78 μg·kg~(-1)·d~(-1),概率评估的P99.9为0.39μg·kg~(-1)·d~(-1);同时概率评估高于双份饭结果,儿童铅膳食暴露概率评估P95为11.08μg·kg~(-1)·d~(-1),双份饭P95为5.75μg·kg~(-1)·d~(-1).在计算正确性验证方面,概率评估模型计算结果与@Risk结果接近,乙酰甲胺磷膳食暴露概率评估计算的P95为4.27μg·kg~(-1)·d~(-1),@Risk计算的P95为4.24 μg·kg~(-1)·d~(-1);消费量及污染物的均数漂移表现为以零为中心的随机误差分布,漂移范围为0.05%～11.9%.结论 开发的中国膳食暴露评估模型软件计算正确,结果合理,对提升我国膳食暴露评估技术水平具有现实意义.     

食品化学物高端暴露膳食模型的建立

目的 建立食品中化学物的高端暴露膳食模型并进行验证.方法 基于人体仅可能同时有2～3种食物的消费量达到人群较高水平的假设,提出计算多种食物来源的食物化学物高端暴露量的膳食模型.采用2011年全国化学污染物和有害因素监测数据库中铅、镉、汞含量数据(样本量分别为45 832、43 862和25 243份)和2002年中国居民健康与营养状况调查中各类食物消费量数据,以半概率分布模型为参考,对模型的重要参数进行选择,并以2010年监测的8种化学污染物在各类食品中的含量数据进行验证.结果 在第90、95、97.5百分位数高端暴露水平下,当分别采用7、12、20、30种食物分类时,含有两个高暴露食物的模型(2+x模型)输出结果与半概率分布模型输出结果(参考值)的相对偏离度均＜0;含3个高暴露食物的模型(3+x模型)输出结果的相对偏离度均>0,但均在±20％之间.进一步对模型进行验证表明,8种不同化学污染物通过3+x模型得到的结果均接近和(或)高于半概率分布模型的结果,相对偏离度在-5％～ 25％之间.结论 3+x高端暴露模型可兼顾暴露评估模型对准确性和保守性的要求,能可靠地对多种食物来源的化学物的高端暴露量进行估计.     

2019-2020年中国肉制品接触材料膳食暴露评估基础参数

目的 掌握中国肉制品食品接触材料的使用情况,构建肉制品食品接触材料膳食暴露评估基础参数数据库.方法 基于食品接触材料膳食暴露评估的"接触面积法"所需数据,于2019-2020年在北京、吉林省和江苏省的现场和网上购买预包装肉制品并结合行业调查,通过核查食品标签及红外光谱仪检测获得相关信息,计算肉制品食品接触材料与单位质量...     

武汉市市售食品中铅污染物摄入量评估

目的了解武汉市各类食品中铅污染水平,根据每标准人日各类食物的摄入量数据,评估武汉市民膳食铅暴露水平。方法采用中国食品污染物监测研究方法 ,制定武汉市食品污染物监测工作方案,用石墨炉原子吸收光谱法检测食品中铅含量,对武汉市2003-2009年食品监测数据进行食品中铅污染的暴露量评估,并根据武汉市居民膳食营养调查中数据进行摄入量评估。结果武汉市食品中铅的平均含量为0.089mg/kg,合格率为94.5%。铅含量较高的前三类食品分别是猪内脏、茶叶和干菌,武汉市城乡居民每标准人重金属铅的日平均摄入量为80.6μg。结论武汉市市售主要食品均存在铅轻微污染,长期食用相对安全。     

上海市成年人膳食中镉暴露水平评估

[目的]了解上海市成年人膳食中镉暴露的基础数据,评估上海市成年人膳食镉暴露风险。[方法]对上海市16类1 680件市售食品中镉含量进行分层随机抽样监测,对上海市1 368名成年人膳食摄入量多阶段随机抽样调查,应用世界卫生组织推荐的食品中化学污染物膳食暴露点评估方法,对上海市成年居民膳食中镉暴露水平进行评估。[结果]上海市成年人平均每周膳食中镉暴露量为0.149 4 mg/人,占暂定每周可耐受摄入量（PTWI）的34.56%。上海市成年人每周膳食中镉暴露量中位数为0.032 4 mg/人,占PTWI的7.50%。上海市成年人每周膳食中镉暴露量（膳食摄入量P90、极端P90）分别为0.287 9 mg/人和0.937 2 mg/人,分别占PTWI的66.59%和216.80%。[结论]上海市成年人膳食中镉暴露水平正常情况下低于PTWI,但仍有进一步降低必要。     

Physiological Approach to Evaluation of Physical Capacity

Studies aimed at linking pollutant burdens to biological response and environmental exposure have yielded interesting preliminary results. Whereas easily collected specimens such as hair and blood have proven utility in estimation of environmental exposure, these tissues cannot, as yet, be considered a good quantitative indicator of many body pollutant burdens. Studies of occupationally exposed groups or groups of individuals with clinically evident disease have failed to clearly implicate pollutant burdens with either disease production or aggravation although, in general, the blood levels of these individuals do reflect increased exposure to pollutants. Studies of multiple tissue sets collected at autopsy are encouraging inasmuch as it appears these tissues will provide useful information about the pollutant burden for constructing predictive models and, in addition, provide flashback capabilities.     

Validity of international, time trend, and migrant studies of dietary factors and disease risk

A linear form relative risk model is used to identify circumstances in which various types of aggregate data lead to valid inferences on relative risk parameters. Upon making a random effects assumption, international or time trend data can lead to appropriate relative risk parameter estimation using iteratively reweighted least-squares procedures. Adequate confounding factor control, however, will typically require data on the distribution of confounding factors in each country or time period. For a simple interpretation of relative risk parameters one may also require data on the joint distribution of primary and confounding factors in each country or time period. Hence disease rate data need to be supplemented by dietary and risk factor survey data in order to avoid confounding bias. Measurement error in individual dietary assessment may, however, limit the ability to quantify the dependence of relative risk on dietary factors, unless the relative risk function is approximately linear in the dietary factors of interest. Most studies of migrant populations involve a comparison of migrant mortality rates with those of their countries of emigration and immigration, with little or no data collection on the dietary habits and risk factors of the migrants themselves. The potential of more comprehensive aggregate data and analytic migrant studies in the diet and disease area is briefly indicated. These issues and methods are illustrated using various types of data pertinent to the association between dietary fat and breast cancer.     

Role of communication media in nutrition knowledge and awareness. An Indian urban study

A questionnaire survey was carried out on 480 adults (>18 years of age) from households of government employees residing in their official residential complex in Hyderabad and belonging to different socio-economic categories. The study involved assessment of dietary knowledge, attitudes and practices (KAP) of the study community, status pertaining to exposure to communication media and usage as well as interplay of these aspects with different socio-economic parameters. Data generated by the study identified many gaps in the dietary KAP and limitations in communication media exposure and utilisation. The need for information on several aspects relating to nutritional value of foods and their usage was apparent among the lower educational and income groups. A close relationship between the extent of exposure to communication media and usage and the pattern of dietary knowledge and practices was elucidated. Women needed greater exposure to media to improve dietary KAP. Education (particularly among women) and income were found to be the most crucial factors limiting the dietary KAP. The greater role to be played by communication media, especially mass media in producing authentic dietary and health information through more creative programmes is brought out. The role of socio-economic factors has been highlighted.     

Microbial risk assessment framework for exposure to amended sludge projects

BACKGROUND: Although the U.S. Environmental Protection Agency has a long history of using risk-based approaches for regulatory purposes, pollutant limits for pathogens in biosolids are not currently based on quantitative risk assessments. OBJECTIVES: We developed and demonstrated a risk-based methodology for assessing the risk to human health from exposure to pathogens via biosolids. MATERIALS: Four models were developed, incorporating direct ingestion, groundwater, and aerosol exposure pathways. Three sources of environmental data were used to estimate risk: pathogen monitoring of sludge, efficacy of sludge treatment, and pathogen monitoring of biosolids. RESULTS: Risk estimates were obtainable even for Class A biosolids, where posttreatment monitoring data are below detectable levels, demonstrating that risk assessments for biosolids exposure are practical. Model analyses suggest that: a) a two-digester design decreases the probability of risks >10(-4) compared with one-digester designs, b) risks associated with exposures to groundwater and aerosol pathways were, in general, lower than exposures to the direct ingestion pathway, and c) secondary transmission can be an important factor in risk estimation. CONCLUSIONS: The risk-based approach presented here provides a tool to a) help biosolids producers interpret the results of biosolids monitoring data in terms of its health implications, b) help treatment plant engineers evaluate the risk-based benefits of operational changes to existing or projected treatment processes, and c) help environmental managers evaluate potential capital improvements and/or land application site placement issues. Regulation of pathogens can now be based on human health risk in a manner parallel to other water-related risks.     

Combining information from multiple surveys to enhance estimation of measures of health

Survey estimates are often affected by non-sampling errors due to missing data, coverage error, and measurement or response error. Such non-sampling errors can be difficult to assess, and possibly correct for, using information from a single survey. Thus, combining information from multiple surveys can be beneficial. In addition, combining information from multiple surveys can help to reduce sampling error. This article describes four examples of projects undertaken by researchers within and outside the National Center for Health Statistics of the Centers for Disease Control and Prevention, in which information from multiple surveys was combined to adjust for non-sampling errors and thereby enhance estimation of various measures of health. The four projects can be described briefly as follows: (1) combining estimates from a survey of households and a survey of nursing homes to extend coverage; (2) using information from an interview survey to bridge the transition in race reporting in the United States census; (3) combining information from an examination survey and an interview survey to improve on analyses of self-reported data; and (4) combining information from two interview surveys to enhance small-area estimation. The article highlights the goals, techniques, and results from the four projects and discusses issues that can arise when information is combined from multiple surveys. Published in 2007 by John Wiley & Sons, Ltd.     

Probabilistic estimation of dietary exposure of the general Japanese population to dioxins in fish, using region-specific fish monitoring data

Many studies show that dietary consumption of fish is the greatest contributor to dioxin exposure of humans in Japan. To establish a link between ocean contamination and human exposure to dioxins in fish, we proposed a method of estimating exposure by integrating region-specific measured concentrations of dioxins in fish samples and information on the production and import-export volumes of fish. The advantage over "total diet studies" (TDS) was that the proposed method could analyze the impact of the geographical variability of ocean contamination on human exposure to dioxins in fish; this may help us to apply more effective measures against dioxin exposure. Probabilistic distributions (probability density functions (PDFs)) were assigned to express the variability in the results of monitoring dioxin concentrations in fish from coastal areas divided according to prefecture, and from offshore and distant waters and imported sources. The Monte Carlo technique was applied for probabilistic estimation of dietary exposure of the general Japanese population to dioxins in fish. The mean and 5th to 95th percentile range of dietary exposure were estimated, respectively, as 67.12 and 22.65-184.35 pg toxic equivalent per day. Sensitivity analysis showed that some specific coastal areas with higher dioxin levels in fish and some with larger production volumes of fish impacted more than others to total exposure and may thus attract priority in the implementation of dioxin abatement measures.