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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.

For NHANES 2003-2004, there were 12,761 persons selected for the sample, 10,122 of those were interviewed (79.3 percent) and 9,643 (75.6 percent) were examined in the mobile examination centers (MEC). Many of the NHANES 2003-2004 questions were also asked in NHANES II 1976-1980, Hispanic HANES 1982-1984, NHANES III 1988-1994, and NHANES 1999-2002. New questions were added to the survey based on recommendations from survey collaborators, NCHS staff, and other interagency work groups. As in past health examination surveys, data were collected on the prevalence of chronic conditions in the population. Estimates for previously undiagnosed conditions, as well as those known to and reported by survey respondents, are produced through the survey. 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 diseases, medical conditions, and health indicators that were studied include: anemia, cardiovascular disease, diabetes and lower extremity disease, environmental exposures, equilibrium, hearing loss, infectious diseases and immunization, kidney disease, mental health and cognitive functioning, nutrition, obesity, oral health, osteoporosis, physical fitness and physical functioning, reproductive history and sexual behavior, respiratory disease (asthma, chronic bronchitis, emphysema), sexually transmitted diseases, skin diseases, and vision. The sample for the survey was selected to represent the United States population of all ages. Special emphasis in the 2003-2004 NHANES was on adolescent health and the health of older Americans. To produce reliable statistics for these groups, adolescents aged 15-19 years and persons aged 60 years and older were over-sampled for the survey. African Americans and Mexican Americans were also over-sampled to enable accurate estimates for these groups. Several important areas in adolescent health, including nutrition and fitness and other aspects of growth and development, were addressed. Since the United States has experienced dramatic growth in the number of older people during the twentieth century, the aging population has major implications for health care needs, public policy, and research priorities. NCHS is working with public health agencies to increase the knowledge of the health status of older Americans. NHANES has a primary role in this endeavor. In the examination, all participants visit the physician who takes their pulse or blood pressure. Dietary interviews and body measurements are included for everyone. All but the very young have a blood sample taken and see the dentist. Depending upon the age of the participant, the rest of the examination includes tests and procedures to assess the various aspects of health listed above. Usually, the older the individual, the more extensive the examination. Some persons who are unable or unwilling to come to the examination center may be given a less extensive examination in their homes.

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 2003-2004 data). (2) Recoded Demographic Variables: these variables include age (age in months for persons through age 19 years, 11 months; age in years for 1- to 84-year-olds, and a top-coded age group of 85 years of age and older), gender, a race/ethnicity variable, current or highest grade of education completed, (less than high school, high school, and more than high school education), country of birth (United States, Mexico, or other foreign born), Poverty Income Ratio (PIR), income, and a pregnancy status variable (adjudicated from various pregnancy related variables). Some of the groupings were made due to limited sample sizes for the two-year data set. (3) Interview and Examination Sample Weight Variables: sample weights are available for analyzing NHANES 2003-2004 data. For a complete listing of survey contents for all years of the NHANES see the document -- Survey Content -- NHANES 1999-2010.

The purpose of the National Health Interview Survey (NHIS) is to obtain information about the amount and distribution of illness, its effects in terms of disability and chronic impairments, and the kinds of health services people receive. Implementation of a redesigned NHIS, consisting of a basic module, a periodic module, and a topical module, began in 1997 (See NATIONAL HEALTH INTERVIEW SURVEY, 1997 [ICPSR 2954]).

The 2001 NHIS contains the Household, Family, Person, Sample Adult, Sample Child, Child Immunization, and Injury and Poison Episode data files from the basic module. Each record in the Household-Level File (Part 1) contains data on type of living quarters, number of families in the household responding and not responding, and the month and year of the interview for each sampling unit.

The Family-Level File (Part 2) is made up of reconstructed variables from the person-level data of the basic module and includes information on sex, age, race, marital status, Hispanic origin, education, veteran status, family income, family size, major activities, health status, activity limits, and employment status, along with industry and occupation.

As part of the basic module, the Person-Level File (Part 3) provides information on all family members with respect to health status, limitation of daily activities, cognitive impairment, and health conditions. Also included are data on years at current residence, region variables, height, weight, bed days, doctor visits, hospital stays, and health care access and utilization.

A randomly-selected adult in each family was interviewed for the Sample Adult File (Part 4) regarding respiratory conditions, renal conditions, AIDS, joint symptoms, health status, limitation of daily activities, and behaviors such as smoking, alcohol consumption, and physical activity. Also included in this file are variables pertaining to the Healthy People 2010 Objectives.

The Sample Child File (Part 5) provides information from an adult in the household on medical conditions of one child in the household, such as respiratory problems, seizures, allergies, and use of special equipment such as hearing aids, braces, or wheelchairs. Also included are variables regarding child behavior, the use of mental health services, and Attention Deficit Hyperactivity Disorder (ADHD).

The Child Immunization File (Part 6) presents information from shot records and supplies vaccination status, along with the number and dates of shots, and information about the chicken pox vaccine.

Episode-based information regarding injuries and poisonings are found in the Injury and Poison Episode File (Part 7), which examines the cause and date of injury or poisoning, loss of time from work or school, and whether the episode resulted in hospitalization.

Information in the Injury and Poison Verbatim File (Part 8) is comprised of narrative text describing injuries, including type of injury, how the injury occurred, and the body part injured.

These data are being released in BETA version to facilitate early access to the study for research purposes. This collection has not been fully processed by NACDA or ICPSR at this time; the original materials provided by the principal investigator were minimally processed and converted to other file types for ease of use. As the study is further processed and given enhanced features by ICPSR, users will be able to access the updated versions of the study. Please report any data errors or problems to user support and we will work with you to resolve any data related issues.

The National Health Interview Survey (NHIS) is conducted annually and sponsored by the National Center for Health Statistics (NCHS), which is part of the U.S. Public Health Service. The purpose of the NHIS is to obtain information about the amount and distribution of illness, its effects in terms of disability and chronic impairments, and the kinds of health services people receive across the United States population through the collection and analysis of data on a broad range of health topics. The redesigned NHIS questionnaire introduced in 1997 (see National Health Interview Survey, 1997 [ICPSR 2954]) consists of a core that remains largely unchanged from year to year, plus an assortment of supplements varying from year to year.

The 2010 NHIS Core consists of three modules: Family, Sample Adult, and Sample Child. The datasets derived from these modules include Household Level, Family Level, Person Level, Injury/Poison Episode Level, Injury/Poison Verbatim Level, Sample Adult Level, and Sample Child level.

The 2010 NHIS supplements consist of stand alone datasets for Cancer Level and Quality of Life data derived from the Sample Adult core and Disability Questions Tests 2010 Level derived from the Family core questionnaire. Additional supplementary questions can be found in the Sample Child dataset on the topics of cancer, immunization, mental health, and mental health services and in the Sample Adult dataset on the topics of epilepsy, immunization, and occupational health.

Part 1, Household Level, contains data on type of living quarters, number of families in the household responding and not responding, and the month and year of the interview for each sampling unit. Parts 2-5 are based on the Family Core questionnaire. Part 2, Family Level, provides information on all family members with respect to family size, family structure, health status, limitation of daily activities, cognitive impairment, health conditions, doctor visits, hospital stays, health care access and utilization, employment, income, participation in government assistance programs, and basic demographic information. Part 3, Person Level, includes information on sex, age, race, marital status, education, family income, major activities, health status, health care costs, activity limits, and employment status. Parts 4 and 5, Injury/Poisoning Episode Level and Injury/Poisoning Verbatim Level, consist of questions about injuries and poisonings that resulted in medical consultations for any family members and contains information about the external cause and nature of the injury or poisoning episode and what the person was doing at the time of the injury or poisoning episode, in addition to the date and place of occurrence.

A randomly-selected adult in each family was interviewed for Part 6, Sample Adult Level, regarding specific health issues, the relation between employment and health, health status, health care and doctor visits, limitation of daily activities, immunizations, and behaviors such as smoking, alcohol consumption, and physical activity. Demographic information, including occupation and industry, also was collected. The respondents to Part 6 also completed Part 7, Cancer Level, which consists of a set of supplemental questions about diet and nutrition, physical activity, tobacco, cancer screening, genetic testing, family history, and survivorship. Part 8, Sample Child Level, provides information from an adult in the household on medical conditions of one child in the household, such as developmental or intellectual disabilities, respiratory problems, seizures, allergies, and use of special equipment like hearing aids, braces, or wheelchairs.

Parts 9 through 13 comprise the additional Supplements and Paradata for the 2010 NHIS. Part 9, Disability Questions Tests 2010 Level, is a supplemental set of six questions asked at the end of the Family Core questionnaire about sensory, mobility, self-care, cognition, and independent living issues. Part 10, Paradata Level, does not contain health related information, but rather data which are related to the interview process, including measures of time, contact-ability, and cooperation. Please see the User Guide for additional information and details. Part 11, Quality of Life Level, was asked to a randomly selected subsection of the Sample Adult questionnaire. Respondents were asked about participation in society, degree of difficulty and functioning in activity domains including vision, hearing, mobility, upper body, learning, cognition, affect, pain, fatigue, and communication. Part 12, Special Sample Adult Disability Weights Level, contains weights for use with an analysis of the merged data from the Sample Adult Level and Disability Questions Tests 2010 Level. Part 13, Sample Child Birth Weights Level, contains corrected birth weight data for 2010. Please see the Survey Description files for additional information and details.

The National Health Interview Survey (NHIS) is conducted annually and sponsored by the National Center for Health Statistics (NCHS), which is part of the U.S. Public Health Service. The purpose of the NHIS is to obtain information about the amount and distribution of illness, its effects in terms of disability and chronic impairments, and the kinds of health services people receive across the United States population through the collection and analysis of data on a broad range of health topics. The redesigned NHIS questionnaire introduced in 1997 (see NATIONAL HEALTH INTERVIEW SURVEY, 1997 [ICPSR 2954]) consists of a Core that remains largely unchanged from year to year, plus an assortment of Supplements varying from year to year.

The 2011 NHIS Core components contain Household, Family, Person, Sample Adult, and Sample Child files. Each record in Part 1, Household Level, contains data on type of living quarters, number of families in the household responding and not responding, and the month and year of the interview for each sampling unit. Part 2, Family Level, is made up of reconstructed variables from the person-level data of the basic module and includes information on sex, age, race, marital status, education, veteran status, family income, family size, major activities, health status, health care costs, activity limits, and employment status, along with industry and occupation. As part of the basic module, Part 3, Person Level, provides information on all family members with respect to health status, limitation of daily activities, cognitive impairment, and health conditions. Also included are variables related to doctor visits, hospital stays, and health care access and utilization. Basic demographic information is provided as well.

A randomly-selected adult in each family was interviewed for Part 4, Sample Adult Level, regarding respiratory conditions, renal conditions, AIDS, joint symptoms, health status, health care and doctor visits, limitation of daily activities, and behaviors such as smoking, alcohol consumption, and physical activity. Part 5, Sample Child Level, provides information from an adult in the household on medical conditions of one child in the household, such as developmental or intellectual disabilities, respiratory problems, seizures, allergies, and use of special equipment like hearing aids, braces, or wheelchairs.

Parts 6 through 11 comprise the additional Supplements and Paradata for the 2011 NHIS. Part 6, Injury/Poison Episode, is an episode-based file that contains information about the external cause and nature of the injury or poisoning episode and what the person was doing at the time of the injury or poisoning episode, in addition to the date and place of occurrence. Part 7, Adult Disability Level and Part 8, Child Disability Level, are a supplemental set of six questions asked at the end of the Sample Adult and Sample Child Questionnaires for half of families that did not receive the Family Disability Supplement. These specific disability questions were only asked of the Sample Adult and the Sample Child. Part 9, Family Disability Level, seeks to identify the subpopulation that is at a greater risk than the general population of experiencing restrictions in social participation, for example, restrictions in employment, education, or civic life. Specific questions ask about respondent difficulty performing daily activities, such as dressing, bathing, or walking. Approximately one half of sample adults were selected to receive the Part 10, Adult Functioning and Disability Level Supplement. Questions were asked about a respondent's functioning in various basic and complex activity domains: vision, hearing, mobility, communication, cognition, upper body, affect, pain, and fatigue. This supplement also included questions designed to capture an individual's ability to participate in society. Follow-up questions on the degree of difficulty, use of assistive devices, and functioning with assistance were included for most domains. Part 11, Paradata Level, does not contain health related information, but rather data which are related to the interview process, including measures of time, contact-ability, and cooperation. Please see the User Guide for additional information and details.

The National Health Interview Survey (NHIS) is conducted annually by the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention (CDC). The main objective of the NHIS is to monitor the health of the United States population through the collection and analysis of data on a broad range of health topics.

The NHIS contains many similar questions every year. The repeated items are called "core questions." Beginning with a new NHIS design in 1997, these core questions were divided into three components -- Family, Sample Adult, and Sample Child.

The 2012 NHIS data release consists of six core data files, a paradata file, the three Disability Questions Tests files, a Functioning and Disability file, and two Complementary and Alternative Medicine files. Users may see the Survey Description document for more details.

The 2012 NHIS contains the core questions, as well as enhanced questions on health care access and utilization. Supplemental topics are covered in the following questionnaires: the Family questionnaire covers subjects of food security; the Sample Adult questionnaire covers subjects of immunization, complementary and alternative medicine, non-cigarette tobacco use, voice, speech, and language; and the Sample Child questionnaire covers subjects of mental health, mental health services, immunization, complementary and alternative medicine, balance, voice, speech, and language. Along with the 2012 NHIS core data files are the Disability Questions Tests 2012 files which contain person-level data collected via a field test of six disability questions. These supplemental questions appeared on the NHIS, at the end of the Family, Sample Adult, and Sample Child Cores.

The Disability Questions Tests 2012 files are released as three separate files. A fourth disability supplement was also fielded in 2012 as part of the Sample Adult Core and is called "Adult Functioning and Disability Level."

The Adult and Child Alternative Health Supplement files were intended to expand on knowledge of alternative medical services. Questions focus on how often various types of alternative therapies are used, the associated costs, and the reasons they are used.

Lastly, the Paradata Level file contains information about the survey and data collection processes; included are data on response rates, keystrokes, interview times, and number of contact attempts.