National Health and Nutrition Examination Survey (NHANES), 1999-2000

The National Health and Nutrition Examination Surveys (NHANES) is a program of studies designed to assess the health and nutritional status of adults and children in the United States. The NHANES combines personal interviews and physical examinations, which focus on different population groups or health topics. These surveys have been conducted by the National Center for Health Statistics (NCHS) on a periodic basis from 1971 to 1994. In 1999 the NHANES became a continuous program with a changing focus on a variety of health and nutrition measurements which were designed to meet current and emerging concerns. The surveys examine a nationally representative sample of approximately 5,000 persons each year. These persons are located in counties across the United States, 15 of which are visited each year. The 1999-2000 NHANES contains data for 9,965 individuals (and MEC examined sample size of 9,282) of all ages. Many questions that were asked in NHANES II, 1976-1980, Hispanic HANES 1982-1984, and NHANES III, 1988-1994, were combined with new questions in the NHANES 1999-2000. The 1999-2000 NHANES collected data on the prevalence of selected chronic conditions and diseases in the population and estimates for previously undiagnosed conditions, as well as those known to and reported by respondents. Risk factors, those aspects of a person's lifestyle, constitution, heredity, or environment that may increase the chances of developing a certain disease or condition, were examined. Data on smoking, alcohol consumption, sexual practices, drug use, physical fitness and activity, weight, and dietary intake were collected. Information on certain aspects of reproductive health, such as use of oral contraceptives and breastfeeding practices, were also collected. The interview includes demographic, socioeconomic, dietary, and health-related questions. The examination component consists of medical, dental, and physiological measurements, as well as laboratory tests. Demographic data file variables are grouped into three broad categories: (1) Status Variables: Provide core information on the survey participant. Examples of the core variables include interview status, examination status, and sequence number. (Sequence number is a unique ID assigned to each sample person and is required to match the information on this demographic file to the rest of the NHANES 1999-2000 data). (2) Recoded Demographic Variables: The variables include age (age in months for persons through age 19 years, 11 months; age in years for 1-84 year olds, and a top-coded age group of 85+ years), gender, a race/ethnicity variable, an education variable (high school, and more than high school education), country of birth (United States, Mexico, or other foreign born), and pregnancy status variable. Some of the groupings were made due to limited sample sizes for the two-year dataset. (3) Interview and Examination Sample Weight Variables: Sample weights are available for analyzing NHANES 1999-2000 data. For a complete listing of survey contents for all years of the NHANES see the document -- Survey Content -- NHANES 1999-2010.

全国健康与营养检查调查（National Health and Nutrition Examination Surveys, NHANES）是旨在评估美国成人与儿童健康及营养状况的系列研究项目。该调查结合个人访谈与体格检查环节，针对不同人群群体或健康主题设置研究重点。该项目由美国国家卫生统计中心（National Center for Health Statistics, NCHS）于1971年至1994年间周期性开展。1999年起，NHANES转为持续性项目，其研究重点随当前及新增的健康与营养相关关切不断调整。每年的调查都会选取具有全国代表性的约5000名样本对象，这些对象分布在美国各地的县份中，每年会走访其中15个县。1999-2000周期的NHANES包含了9965名各年龄段个体的数据（其中经MEC检查的有效样本量为9282）。NHANES II（1976-1980年）、西班牙裔NHANES（1982-1984年）及NHANES III（1988-1994年）中的诸多问卷问题，与1999-2000周期NHANES新增问题进行了整合。1999-2000周期的NHANES收集了人群中特定慢性病与疾病的患病率数据，以及此前未被诊断、受访者已知并上报的病症相关估算值。研究同时考察了风险因素——即可能提升个体罹患特定疾病或病症概率的生活方式、体质、遗传或环境相关因素。调查收集了吸烟、饮酒、性行为、药物使用、体能与活动水平、体重及膳食摄入相关数据，还收集了生殖健康相关信息，例如口服避孕药使用情况与母乳喂养行为。访谈环节涵盖人口统计学、社会经济、膳食及健康相关问题；检查环节则包含内科、牙科及生理学测量，以及实验室检测。人口统计学数据文件的变量可分为三大类：(1) 状态变量：提供调查参与者的核心信息，核心变量示例包括访谈状态、检查状态及序列编号（序列编号为每位样本对象分配的唯一标识符，用于将该人口统计学文件中的信息与1999-2000周期NHANES的其他数据进行匹配）。(2) 重编码人口统计学变量：此类变量包括年龄（19岁11个月及以下人群以月龄记录，1-84岁人群以年龄记录，85岁及以上为封顶年龄组）、性别、种族/族裔变量、教育程度变量（高中及以上学历）、出生国家（美国、墨西哥或其他外国出生人群）及妊娠状态变量。部分分组设置是由于两年期数据集的样本量有限。(3) 访谈与检查样本权重变量：样本权重可用于分析1999-2000周期的NHANES数据。如需查阅NHANES所有年份的完整调查内容清单，请参阅文档——《调查内容——NHANES 1999-2010》。