This report describes the methods used to create NHANES 2011-2014 sample weights and variance units for the public-use data files, including sample weights for selected subsamples, such as the fasting subsample. The impacts of sample design changes on estimation for NHANES 2011-2014 and the addition of the NHANES National Youth Fitness Survey (NNYFS) 2012 are described. Approaches that data users can employ to modify sample weights when combining survey cycles or when combining subsamples are also included.

Data System. The National Health and Nutrition Examination Survey (NHANES), conducted by the National Center for Health Statistics, is a cross-sectional survey on the health and nutritional status of US adults and children. Data Collection/Processing. A complex, multistage probability design is used to select a sample representative of the US civilian, noninstitutionalized population. NHANES includes in-home interviews, physical examinations, and biospecimen collection. About 5000 persons are examined annually. Since 2011, NHANES has been oversampling Asian Americans in addition to traditionally oversampled groups, including Hispanics and non-Hispanic Blacks. Data Analysis/Dissemination. Data are publicly released online in 2-year cycles. Some data, because of disclosure risk, are only available through the Research Data Center. Data users should read documentation, examine sample sizes and response rates, and account for the complex survey design. With publicly released data, analyses of Asians as a single group is only possible; some Asian subgroup analyses may be conducted through the Research Data Center. Public Health Implications. Oversampling Asians in NHANES 2011-2018 allows national estimates to be computed on health conditions, nutrition, and risk factors of public health importance on this growing subpopulation of Asian Americans.

Background California is the most populated state and Los Angeles County is the most populated county in the United States. National Health and Nutrition Examination Survey (NHANES) sample weights and variance units were developed for these places to obtain subnational estimates. Objective This report describes the California and Los Angeles County NHANES 1999-2006 and 2007-2014 samples, including the creation of the sample weights and variance units and descriptions of the resulting data files. Some analytic guidelines are provided. Results Eight years of NHANES data were combined for each data file to provide an adequate sample size and reduce disclosure risks. Because Los Angeles County has been a self-representing primary sampling unit, sample weights for Los Angeles County were relatively straightforward. However, a modelbased approach was used to create sample weights for California. The relatively large proportion of Mexican- American and other Hispanic persons in California, coupled with the different NHANES 1999-2014 sample design requirements for oversampling these groups within the small number of NHANES locations selected each cycle, led to a relatively large size of these groups in the California and Los Angeles County NHANES files. For example, 1,137 and 374 of the 3,353 Mexican-Americans persons in NHANES 2007-2014 were in the California and Los Angeles County samples, respectively. Conclusion The California and Los Angeles County NHANES 1999-2006 and 2007-2014 samples are available in the National Center for Health Statistics Research Data Center.

The aim of this study is to describe trends in the awareness, treatment, and control of hypertension; mean blood pressure; and the classification of blood pressure among US adults 2003 to 2012. Using data from the National Health and Nutrition Examination Survey 2003 to 2012, a total of 9255 adult participants aged ≥18 years were identified as having hypertension, defined as measured blood pressure ≥140/90 mm Hg or taking prescription medication for hypertension. Awareness and treatment among hypertensive adults were ascertained via an interviewer administered questionnaire. Controlled hypertension among hypertensive adults was defined as systolic blood pressure <140 mm Hg and diastolic blood pressure <90 mm Hg. Blood pressure was categorized as optimal blood pressure, prehypertension, and stage I and stage II hypertension. Between 2003 and 2012, the percentage of adults with controlled hypertension increased ( P -trend <0.01). Hypertensive adults with optimal blood pressure and with prehypertension increased from 13% to 19% and 27% to 33%, respectively ( P -trend <0.01 for both groups). Among hypertensive adults who were taking antihypertensive medication, uncontrolled hypertension decreased from 38% to 30% ( P -trend <0.01). Similarly, a decrease in mean systolic blood pressure was observed ( P -trend <0.01); however, mean diastolic blood pressure remained unchanged. The trend in the control of blood pressure has improved among hypertensive adults resulting in a higher percentage with blood pressure at the optimal or prehypertension level and a lower percentage in stage I and stage II hypertension. Overall, mean systolic blood pressure decreased as did the prevalence of uncontrolled hypertension among the treated hypertensive population.

Objective. We estimated the prevalence of preventive aspirin and/or other antiplatelet medication use and the dosage of aspirin use in the U.S. adult population. Methods. We conducted cross-sectional analyses of a representative sample ( n=3,599) of U.S. adults aged ≥40 years from the National Health and Nutrition Examination Survey, 2011–2012. Results. In 2011–2012, one-third of U.S. adults aged ≥40 years reported taking preventive aspirin and/or other antiplatelet medications, 97% of whom indicated preventive aspirin use. Preventive aspirin use increased with age (from 11% of those aged 40–49 years to 54% of those ≥80 years of age, p<0.001). Non-Hispanic white (35%) and black (30%) adults were more likely to take preventive aspirin than non-Hispanic Asian (20%, p<0.001) and Hispanic (22%, p=0.013) adults. Adults with, compared with those without health insurance, and adults with ≥2 doctor visits in the past year, diagnosed diabetes, hypertension, or high cholesterol were twice as likely to take preventive aspirin. Among those with cardiovascular disease, 76% reported taking preventive aspirin and/or other antiplatelet medications, of whom 91% were taking preventive aspirin. Among adults without cardiovascular disease, 28% reported taking preventive aspirin. Adherence rates to medically recommended aspirin use were 82% overall, 91% for secondary prevention, and 79% for primary prevention. Among current preventive aspirin users, 70% were taking 81 milligrams (mg) of aspirin daily and 13% were taking 325 mg of aspirin daily. Conclusion. The vast majority of antiplatelet therapy is preventive aspirin use. A health-care provider's recommendation to take preventive aspirin is an important determinant of current preventive aspirin use.

Childhood obesity is a major public health problem associated with many adverse health outcomes in adulthood (1). During 2011–2012, nearly 17% of children and adolescents were obese (2). Weight status misperception occurs when the child’s perception of their weight status differs from their actual weight status based on measured height and weight. Accurate weight status self-perception has been linked to appropriate weight control behaviors in youth. The National Health and Nutrition Examination Survey (NHANES) data for children and adolescents aged 8–15 years offers an opportunity to examine weight perception status in this age group.

Objectives: To describe trends in the awareness, treatment and control of hypertension; mean blood pressure; and the classification of blood pressure among U.S. adults 2003-2012. Methods and Results: Using data from the National Health and Nutrition Examination Survey 2003-2012, a total of 9,255 adult participants aged 18 and older were identified as having hypertension, defined as measured blood pressure ≥ 140/90 mm Hg or taking prescription medication for hypertension. Awareness and treatment among hypertensive adults were ascertained via an interviewer administered questionnaire. Controlled hypertension among hypertensive adults was defined as systolic blood pressure <140 mm Hg and diastolic blood pressure < 90 mm Hg. Blood pressure was categorized as optimal blood pressure, prehypertension, stage I hypertension and stage II hypertension. Between 2003 and 2012, the percent of adults with controlled hypertension increased ( p -trend <0.01). Hypertensive adults with optimal blood pressure and with prehypertension increased from 13% to 19% and 27% to 33%, respectively ( p - trend < 0.01). Among hypertensive adults who were taking anti-hypertensive medication, uncontrolled hypertension decreased from 38% to 30% ( p -trend <0.01). Similarly, a decrease in mean systolic blood pressure was observed ( p -trend <0.01); however, mean diastolic blood pressure remained unchanged. Conclusion: The trend in the control of blood pressure has improved among hypertensive adults resulting in a higher percent with blood pressure at the optimal or prehypertension level and a lower percent in stage I and stage II hypertension. Overall, mean systolic blood pressure decreased as did the prevalence of uncontrolled hypertension among the treated hypertensive population.

During 2003–2012, there was a significant increase in the percentage of adults aged 40 and over who used a prescription cholesterol-lowering medication. In 2003–2004, one in five adults reported using a prescription cholesterol-lowering medication in the past 30 days. By 2011–2012, that number had risen to one in four adults. In 2011–2012, the majority of adults using a cholesterol-lowering medication reported using a statin alone (83%). Ten percent used both a statin and a nonstatin and another 7% used only a nonstatin. Simvastatin was the most commonly used medication, with 42% of all cholesterol-lowering medication users reporting its use, followed by atorvastatin (20.2%). Use of a prescription cholesterol-lowering medication increased with age but was similar between men and women and race and Hispanic origin groups. Adults aged 40–64 who reported having health insurance or prescription medication coverage were more likely to take prescription cholesterol-lowering medications. Hypercholesterolemia or high cholesterol is one of the most common preventable risk factors for atherosclerotic CVD. In 2011–2012, more than 30 million Americans aged 20 and over (13%) had measured high total cholesterol (5). There is extensive and consistent evidence supporting the use of cholesterol-lowering medication, especially statins, in addition to lifestyle changes, to treat lipid disorders and reduce atherosclerotic CVD events. The 2013 cholesterol treatment guidelines updated recommendations for statin therapy on the basis of low-density lipid cholesterol levels and atherosclerotic CVD risks (6). Approximately 71% of adults with diagnosed CVD, 63% of those with diagnosed diabetes, and 54% of those with diagnosed hypercholesterolemia reported taking prescription cholesterol-lowering medications.

Physical activity (PA) can improve cardiorespiratory fitness in youth. Federal guidelines recommend children and adolescents do 60+ minutes of PA daily, with most of the activity being moderate or vigorous intensity aerobic PA. Data from 450 youth, aged 12‐15 years, who participated in the 2012 National Health and Nutrition Examination Survey (NHANES) National Youth Fitness Survey (NNYFS) were used for this analysis. The NNYFS was a one‐year survey designed to collect nationally representative data on PA and fitness levels of youth in the US. Maximal oxygen uptake (VO2max) was estimated using a submaximal treadmill test. The percentage of youth in the healthy cardiorespiratory fitness zone (HFZ, based on FITNESSGRAM performance standards) was based on the estimated VO2max values. Overall, 41.9% (SE 2.8) of youth aged 12‐15 years were in the HFZ. More boys (50.2% (SE 3.7)) than girls (33.2% (SE 2.8)) were in the HFZ. No significant differences were observed by race and Hispanic origin. Of those categorized in the HFZ, more youth of normal weight (54.3% (2.8)) compared with overweight (29.2% (SE 5.4)) or obese (17% (SE 4.6)) youth, were in the HFZ. A higher percentage of youth in the HFZ met aerobic PA guidelines (35.0% (SE 1.8)) compared with those not in the HFZ (22.6% (2.3)). Our findings indicate that while half of boys aged 12‐15 years old were categorized in the HFZ, only about one‐third of girls were categorized in the HFZ. It is important to continue to assess aerobic fitness levels in youth on a national level in order to monitor the progress of interventions and federal guidelines aimed at promoting PA in youth.

Background Data collection for the National Health and Nutrition Examination Survey (NHANES) consists of a household screener, an interview, and a physical examination. The screener primarily determines whether any household members are eligible for the interview and examination. Eligibility is established using preset selection probabilities for the desired demographic subdomains. After an eligible sample person is selected, the interview collects person-level demographic, health, and nutrition information, as well as information about the household. The examination includes physical measurements, tests such as hearing and dental examinations, and the collection of blood and urine specimens for laboratory testing. Objectives This report provides some background on the NHANES program, beginning with the first survey cycle in the 1970s and highlighting significant changes since its inception. The report then describes the broad design specifications for the 2011-2014 survey cycle, including survey objectives, domain and precision specifications, and operational requirements unique to NHANES. The report also describes details of the survey design, including the calculation of sampling rates and sample selection methods. Documentation of survey content, data collection procedures, estimation methods, and methods to assess nonsampling errors are reported elsewhere.

The Academy of Nutrition and Dietetics recognizes the importance of including dietary supplements (DS) in assessing and planning dietary intakes.1 DS use in the United States has increased markedly during the past 30 years and is now widespread across all segments of society.2-6 At present, more than half of adults and a third of US children have used one or more DS within the past 30 days, with multivitamin, multimineral (MVMM) products especially common.7,8 Because supplements are now major sources of several nutrients, such as calcium and vitamin D, in American diets, it is important for registered dietitian nutritionists (RDNs) to include their contributions when assessing intakes or planning diets.

KEY FINDINGSData from the combined National Health and Nutrition Examination Survey (NHANES) and the NHANES National Youth Fitness Survey, 2012. In 2012, about one-quarter of U.S. youth aged 12-15 years engaged in moderate-to-vigorous physical activity for at least 60 minutes daily. Basketball was the most common activity reported among active boys, followed by running, football, bike riding, and walking. Running was the most common activity among active girls, followed by walking, basketball, dancing, and bike riding. The percentage of male youth who were physically active for at least 60 minutes daily decreased as weight status increased. The 2008 Physical Activity Guidelines for Americans, which have been adopted by the First Lady's Let's Move! initiative and the American Academy of Pediatrics, recommend that youth participate in daily moderate-to-vigorous physical activity for at least 60 minutes (1-5). This report presents the most recent national data from 2012 on self-reported physical activity among youth aged 12-15 years, by sex and weight status. This report also describes the most common types of physical activities--outside of school-based physical education (PE) or gym classes--in which youth engage.

Data from the National Health and Nutrition Examination Survey (NHANES), 1999-2004 and the NHANES National Youth Fitness Survey, 2012 In 2012, about 42% of U.S. youth aged 12-15 years had adequate levels of cardiorespiratory fitness. The percentage of youth who had adequate levels of cardiorespiratory fitness did not differ by race and Hispanic origin, or by family income-to-poverty ratio. The percentage of youth who had adequate levels of cardiorespiratory fitness decreased as weight status increased. The percentage of youth aged 12-15 who had adequate levels of cardiorespiratory fitness decreased from 52.4% in 1999-2000 to 42.2% in 2012. Physical fitness has been defined as "a set of attributes that people have or achieve that relates to the ability to perform physical activity" (1). Cardiorespiratory fitness is one component of physical fitness and is defined as the "ability of the circulatory and respiratory systems to supply fuel during sustained physical activity and to eliminate fatigue products after supplying fuel" (1). Cardiorespiratory fitness is most often measured by maximal oxygen uptake (VO2max), which is the maximum capacity of the body to transport and use oxygen during physical activity (2). This report presents the most recent national data on the percentage of youth who had adequate levels of cardiorespiratory fitness. Adequate levels of cardiorespiratory fitness are based on standards that are age- and sex-specific and established based on how fit children need to be for good health.

BACKGROUND:The National Health and Nutrition Examination Survey's (NHANES) National Youth Fitness Survey (NNYFS) was conducted in 2012 by the Centers for Disease Control and Prevention's National Center for Health Statistics (NCHS). NNYFS collected data on physical activity and fitness levels to evaluate the health and fitness of children aged 3-15 in the United States. The survey comprised three levels of data collection: a household screening interview (or screener), an in-home personal interview, and a physical examination. The screener's primary objective was to determine whether any children in the household were eligible for the interview and examination. Eligibility was determined by preset selection probabilities for desired sex-age subdomains. After selection, the in-home personal interview collected demographic, health, physical activity, and nutrition information about the child as well as information about the household. The examination included physical measurements and fitness tests.OBJECTIVES:This report provides background on the NNYFS program and summarizes the survey's sample design specifications. The report presents NNYFS estimation procedures, including the methods used to calculate survey weights for the full sample as well as a combined NHANES/NNYFS sample for 2012 (accessible only through the NCHS Research Data Center). The report also describes appropriate variance estimation methods. Documentation of the sample selection methods, survey content, data collection procedures, and methods to assess nonsampling errors are reported elsewhere.

The aim of this study is to describe trends in the awareness, treatment, and control of hypertension; mean blood pressure; and the classification of blood pressure among US adults 2003 to 2012. Using data from the National Health and Nutrition Examination Survey 2003 to 2012, a total of 9255 adult participants aged ≥18 years were identified as having hypertension, defined as measured blood pressure ≥140/90 mm Hg or taking prescription medication for hypertension. Awareness and treatment among hypertensive adults were ascertained via an interviewer administered questionnaire. Controlled hypertension among hypertensive adults was defined as systolic blood pressure <140 mm Hg and diastolic blood pressure <90 mm Hg. Blood pressure was categorized as optimal blood pressure, prehypertension, and stage I and stage II hypertension. Between 2003 and 2012, the percentage of adults with controlled hypertension increased (P-trend <0.01). Hypertensive adults with optimal blood pressure and with prehypertension increased from 13% to 19% and 27% to 33%, respectively (P-trend <0.01 for both groups). Among hypertensive adults who were taking antihypertensive medication, uncontrolled hypertension decreased from 38% to 30% (P-trend <0.01). Similarly, a decrease in mean systolic blood pressure was observed (P-trend <0.01); however, mean diastolic blood pressure remained unchanged. The trend in the control of blood pressure has improved among hypertensive adults resulting in a higher percentage with blood pressure at the optimal or prehypertension level and a lower percentage in stage I and stage II hypertension. Overall, mean systolic blood pressure decreased as did the prevalence of uncontrolled hypertension among the treated hypertensive population.

Weight misperception in children and adolescents may lead to unhealthy or excessive weight control practices among overweight, underweight or normal weight individuals. Accurate self‐perception of weight status has been linked to appropriate weight control behaviors in youth.The objective of this study was to examine gender and racial/ethnic differences in prevalence of weight misperception among children and adolescents.We used data from 4355 children and adolescents aged 8‐15 years who participated in NHANES 2005‐2010. Accuracy of weight perception status was determined by comparing self‐reported weight status (overweight, about right and underweight) to actual weight status based on measured height and weight. The weight misperception prevalence was estimated and compared among age, gender and race/ethnic groups.Nearly, 29% of children and adolescents have misperception of their weight status. Weight misperception is more common among boys than girls and among children than adolescents. The prevalence of weight status misperception was lowest among non‐Hispanic white children and adolescents (26.5%) compared to non‐Hispanic black (33.4%) and Mexican‐American (33.3%) children and adolescents.Current estimates of weight perception status in children and adolescent may be useful in developing obesity prevention programs and in promoting healthy weight control behaviors.

Little information is available on temporal trends in sodium intake in the U.S. population using urine sodium excretion as a biomarker. Our aim was to assess 1988–2010 trends in estimated 24-h urine sodium (24hUNa) excretion among U.S. adults (age 20–59 y) participating in the cross-sectional NHANES. We used subsamples from a 1988–1994 convenience sample, a 2003–2006 one-third random sample, and a 2010 one-third random sample to comply with resource constraints. We estimated 24hUNa excretion from measured sodium concentrations in spot urine samples by use of calibration equations (for men and women) derived from the International Cooperative Study on Salt, Other Factors, and Blood Pressure study. Estimated 24hUNa excretion increased over the 20-y period [1988–1994, 2003–2006, and 2010; means ± SEMs (n): 3160 ± 38.4 mg/d (1249), 3290 ± 29.4 mg/d (1235), and 3290 ± 44.4 mg/d (525), respectively; P-trend = 0.022]. We observed significantly higher mean estimated 24hUNa excretion in each survey period (P < 0.001) for men compared with women (31–33%) and for persons with a higher body mass index (BMI; 32–35% for obese vs. normal weight) or blood pressure (17–26% for hypertensive vs. normal blood pressure). After adjusting for age, sex, and race-ethnicity, temporal trends in mean estimated 24hUNa excretion remained significant (P-trend = 0.004). We observed no temporal trends in mean estimated 24hUNa excretion among BMI subgroups, nor after adjusting for BMI. Although several limitations apply to this analysis (the use of a convenience sample in 1988–1994 and using estimated 24hUNa excretion as a biomarker of sodium intake), these first NHANES data suggest that mean estimated 24hUNa excretion increased slightly in U.S. adults over the past 2 decades, and this increase may be explained by a shift in the distribution of BMI.

BACKGROUND:Data collection for the National Health and Nutrition Examination Survey (NHANES) comprises three levels: a household screener, an interview, and a physical examination. The primary objective of the screener is to determine whether any household members are eligible for the interview an dexamination. Eligibility is determined by preset selection probabilities for the desired demographic subdomains. After an eligible sample person is selected, the interview collects person-level demographic, health, and nutrition information, as well as information about the household. The examination includes physical measurements, tests such as hearing and dental examinations, and the collection of blood and urine specimens for laboratory testing.OBJECTIVES:This report provides some background on the NHANES program, beginning with the first survey cycle in the 1970s and highlighting significant changes since its inception. The report then describes the broad design specifications for the 2007-2010 survey cycle, including survey objectives, domain and precision specifications, and operational requirements unique to NHANES. In addition, the report describes the details of the survey design, including the calculation of sampling rates and sample selection methods. Documentation of survey content, data collection procedures, estimation methods, and methods to assess nonsampling errors are reported elsewhere.