Development of a psychosocial distress measure for Ugandan adolescents living with HIV.

Psychological distress among adolescents living with HIV (ALH) has been associated with risky behaviors including non-adherence to anti-retroviral therapy, leading to increased risk for AIDS morbidity and mortality. Efforts to establish the nature, prevalence, and impact of psychological distress among ALH in Uganda are hindered by the lack of culturally relevant assessment tools. The purpose of this study was to develop and test a measure for psychological distress for Ugandan ALH aged 12-19 years (N = 508; 53.1 % female). Using a mixed method approach, we developed and tested a 25-item checklist with six subscales-anhedonia, depressive-anxiety, isolation, suicidal ideation, sleep problems, and somatization. We found adequate reliability for the scale (α = 0.89), and a satisfactory measurement structure in our confirmatory factor analyses (RMSEA <1.0, and CFI and TLI >0.90). We discuss the potential use of this culturally sensitive scale to examine psychological distress among ALH in Uganda.

Participation in clinical research: perspectives of adult patients and parents of pediatric patients undergoing hematopoietic stem cell transplantation.

Despite major improvements over the past several decades, many patients undergoing hematopoietic stem cell transplantations (HSCT) continue to suffer from significant treatment-related morbidity and mortality. Clinical research studies (trials) have been integral to advancing the standard of care in HSCT. However, 1 of the biggest challenges with clinical trials is the low participation rate. Although barriers to participation in cancer clinical trials have been previously explored, studies specific to HSCT are lacking. The current study was undertaken to examine the knowledge, attitudes, and perceptions of HSCT patients regarding clinical trials. As members of focus groups, participants responded to open-ended questions that assessed factors influencing decision-making about HSCT clinical trials. Suggestions for improvements in the recruitment process were also solicited among participants. Seventeen adult HSCT patients and 6 parents of pediatric HSCT patients participated in the study. The median age was 56 years (range, 18 to 70) and 44 years (range, 28 to 54) for adult patients and parents, respectively. Participants universally indicated that too much information was provided within the informed consents and they were intimidated by the medical and legal language. Despite the large amount of information provided to them at the time of study enrollment, the participants had limited knowledge retention and recall of study details. Nevertheless, participants reported overall positive experiences with clinical trial participation and many would readily choose to participate again. A common concern among participants was the uncertainty of study outcome and general lack of feedback about results at the end of the study. Participants suggested that investigators provide more condensed and easier to understand informed consents and follow-up of study findings. These findings could be used to help guide the development of improved consent documents and enhanced participation in research studies, thereby affecting the future design of HSCT research protocols.

Responsive Design, Weighting, andVariance Estimation in the 2006-2010 National Survey of Family Growth.

Objective-The National Survey of Family Growth (NSFG) collects data on pregnancy, childbearing, men's and women's health, and parenting from a national sample of men and women aged 15-44 in the United States. The 2006-2010 NSFG design was a significant departure from the previous periodic design, used in 1973-2002. This report shows fieldwork results and weighting, imputation, and variance estimation procedures. The report should be useful to users of the 2006-2010 public-use data file and to survey methodologists wishing to learn how the NSFG was conducted. Methods-NSFG's new design is based on an independent national probability sample of men and women aged 15-44. The University of Michigan's Institute for Social Research conducted fieldwork under a contract with the National Center for Health Statistics. Professional female interviewers conducted in-person, face-to-face interviews using laptop computers. A responsive design approach was used in planning and managing the fieldwork for NSFG to control costs and reduce nonresponse bias. Results-The 2006-2010 NSFG is based on 22,682 completed interviews-10,403 interviews with men and 12,279 with women. Interviews with men lasted an average of 52 minutes, and for women, 71 minutes. Weighted response rates were 75% among men, 78% among women, and 77% overall. Analysis of NSFG data requires the use of sampling weights and estimation of sampling errors that account for the complex sample design and estimation features of the survey. Sampling weights are provided on the data files. The rate of missing data in the survey is generally low.

Attitudes of pregnant women towards collection of biological specimens during pregnancy and at birth.

Epidemiological investigations of maternal and child health may involve the collection of biological specimens, including cord blood and the placenta; however, the attitudes of pregnant women towards participation in the collection of biological specimens have been studied rarely. We evaluated attitudes towards collection and storage of biological specimens, and determined whether attitudes differed by maternal characteristics, in a cross-sectional study of pregnant women residing in Kent County, Michigan. Women were interviewed at their first visit for prenatal care between April and October 2006 (n = 311). Willingness to participate was highest for maternal blood collection (72%), followed by storage of biological specimens (68%), placenta collection (64%), and cord blood collection (63%). About one-quarter of women (25-28% by procedure) would not participate even if compensated. Hispanic ethnicity was associated with unwillingness to participate in maternal blood collection (OR = 2.16 [95% CI 1.15, 4.04]). Primiparity was associated with unwillingness to participate in cord blood collection (OR = 1.72 [95% CI 1.23, 2.42]). Among women willing to participate, Hispanic women were less likely to require compensation; while higher educated, married and primiparous women were more likely to require compensation. In conclusion, while many pregnant women were willing to participate in biological specimen collection, some women were more resistant, in particular Hispanic and primiparous women. Targeting these groups of women for enhanced recruitment efforts may improve overall participation rates and the representativeness of participants in future studies of maternal and child health.

A nationally representative sample of veteran and matched non-veteran college students: Mental health symptoms, suicidal ideation, and mental health treatment.

Objective To assess mental health symptoms, suicidal ideation/behaviors, and treatment among a nationally representative probability sample of student veterans. Participants: Student veterans enrolled in post-secondary educational institutions and matched comparison students. Methods: Sampled participants completed an online survey (n = 1,838). Analyses accounted for the complex sample design and non-response. Results: Substantial percentages of student veterans screened positive for: depression (36.9%, 95% CI: 31.1-42.7), PTSD (35.7%, 95% CI 29.9-41.5), anxiety (29.5%, 95% CI 26.8-32.2), and suicidal ideation (14.6%, 95% CI 12.1-17.1), with student veterans having odds ratios between 1.7 to 2.4 for positive screens compared to non-veteran students. Only 41.5% (95% CI 33.0-50.0) of student veterans with positive screens received treatment, although they had 50% higher odds of receiving treatment than non-veteran students. Conclusions: Student veterans have high rates of mental health symptoms and low rates of treatment. However, they are more likely to receive treatment than comparison students.

Vaccination Inequality in India, 2002-2013.

INTRODUCTION: India's childhood vaccination coverage has increased amid the implementation of national health policies intended to improve immunization levels. However, there is a dearth of contemporary studies comparing state-level childhood vaccination rates across India's highly diverse states and territories. This study assesses SES-based inequalities in childhood vaccination by state for 2002-2013. METHODS: National surveys from 2002 to 2004, 2007 to 2008, and 2012 to 2013 were used for analyses. Household SES was assessed using an asset index created through principal component analysis. Full vaccination comprised 1 dose bacille Calmette-Guerin, 3 doses diphtheria-pertussis-tetanus vaccine, 3 doses oral polio vaccine, and 1 dose measles-containing vaccine at age 12-60 months. Inequality analyses were stratified by 3 time periods and by government-designated high focus group versus non-high focus group states. RESULTS: Childhood vaccination steadily increased between 2002 and 2013 in high focus group states but fell in some non-high focus group states, whereas SES-based vaccination inequalities generally decreased in both. In 2012-2013, rural areas had lower vaccination rates than urban areas in high focus group states but similar vaccination rates as urban areas in non-high focus group states. Increases in vaccination rates were not consistently accompanied by improvements in SES-based inequalities in vaccination. CONCLUSIONS: Childhood vaccination in India has improved overall, although increases are more pronounced in high focus group states than in non-high focus group states over the study period. The gap in coverage between these states decreased over time owing in part to the latter experiencing reductions in full vaccination rates during 2007-2013. SES-based vaccination disparities persist in India, highlighting the need to improve vaccination rates for all children, especially those from disadvantaged and underserved groups. SUPPLEMENT INFORMATION: This article is part of a supplement entitled Global Vaccination Equity, which is sponsored by the Global Institute for Vaccine Equity at the University of Michigan School of Public Health.

The 2006-2010 National Survey of Family Growth: sample design and analysis of a continuous survey.

OBJECTIVE: The National Survey of Family Growth (NSFG) collects data on pregnancy, childbearing, men's and women's health, and parenting from a national sample of women and men 15-44 years of age in the United States. This report describes the sample design for the NSFG's new continuous design and the effects of that design on weighting and variance estimation procedures. A working knowledge of this information is important for researchers who wish to use the data. Two data files are being released--the first covering 2.5 years (30 months) of data collection and the second after all data have been collected. This report is being released with the first data file. A later report in this Series will include specific results of the weighting, imputation, and variance estimation. METHODS: The NSFG's new design is based on an independent, national probability sample of women and men 15-44 years of age. Fieldwork was carried out by the University of Michigan's Institute for Social Research (ISR) under a contract with the National Center for Health Statistics (NCHS). In-person, face-to-face interviews were conducted by professional female interviewers using laptop computers. RESULTS: Analysis of NSFG data requires the use of sampling weights and estimation of sampling errors that account for the complex sample design and estimation features of the survey. Sampling weights are provided on the data files. The rate of missing data in the survey is generally low. However, missing data were imputed for about 600 key variables (called "recodes") that are used for most analyses of the survey. Imputation was accomplished using a multiple regression procedure with software called IVEware, available from the University of Michigan website.

Estimating population distributions when some data are below a limit of detection by using a reverse Kaplan-Meier estimator.

BACKGROUND: Data with some values below a limit of detection (LOD) can be analyzed using methods of survival analysis for left-censored data. The reverse Kaplan-Meier (KM) estimator provides an effective method for estimating the distribution function and thus population percentiles for such data. Although developed in the 1970s and strongly advocated since then, it remains rarely used, partly due to limited software availability. METHODS: In this paper, the reverse KM estimator is described and is illustrated using serum dioxin data from the University of Michigan Dioxin Exposure Study (UMDES) and the National Health and Nutrition Examination Survey (NHANES). Percentile estimates for left-censored data using the reverse KM estimator are compared with replacing values below the LOD with the LOD/2 or LOD/ radical2. RESULTS: When some LODs are in the upper range of the complete values, and/or the percent censored is high, the different methods can yield quite different percentile estimates. The reverse KM estimator, which is the nonparametric maximum likelihood estimator, is the preferred method. Software options are discussed: The reverse KM can be calculated using software for the KM estimator. The JMP and SAS (SAS Institute, Cary, NC) and Minitab (Minitab, Inc, State College, PA), software packages calculate the reverse KM directly using their Turnbull estimator routines. CONCLUSION: The reverse KM estimator is recommended for estimation of the distribution function and population percentiles in preference to commonly used methods such as substituting LOD/2 or LOD/ radical2 for values below the LOD, assuming a known parametric distribution, or using imputation to replace the left-censored values.

Estimation of background serum 2,3,7,8-TCDD concentrations by using quantile regression in the UMDES and NHANES populations.

BACKGROUND: The goal of the present study was to quantify the population-based background serum concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by using data from the reference population of the 2005 University of Michigan Dioxin Exposure Study (UMDES) and the 2003-2004 National Health and Nutrition Examination Survey (NHANES). METHODS: Multiple imputation was used to impute the serum TCDD concentrations below the limit of detection by combining the 2 data sources. The background mean, quartiles, and 95th percentile serum TCDD concentrations were estimated by age and sex by using linear and quantile regressions for complex survey data. RESULTS: Any age- and sex-specific mean, quartiles, and 95th percentiles of background serum TCDD concentrations of study participants between ages 18 and 85 years can be estimated from the regressions for the UMDES reference population and the NHANES non-Hispanic white population. For example, for a 50-year-old man in the reference population of UMDES, the mean, quartiles, and 95th percentile serum TCDD concentrations are estimated to be 1.1, 0.6, 1.1, 1.8, and 3.3 parts per trillion, respectively. The study also shows that the UMDES reference population is a valid reference population for serum TCDD concentrations for other predominantly white populations in Michigan. CONCLUSION: The serum TCDD concentrations increased with age and increased more over age in women than in men, and hence estimation of background concentrations must be adjusted for age and sex. The methods and results discussed in this article have wide application in studies of the concentrations of chemicals in human serum and in environmental samples.

Healthy aging in neighborhoods of diversity across the life span (HANDLS): overcoming barriers to implementing a longitudinal, epidemiologic, urban study of health, race, and socioeconomic status.

OBJECTIVE: Examine the influences of race, socioeconomic status, sex, and age on barriers to participation in a study of cross-sectional differences and longitudinal changes in health-related outcomes. METHODS: We designed a multidisciplinary, community-based, prospective longitudinal epidemiologic study among socioeconomically diverse African Americans and Whites. We recruited 3722 participants from Baltimore, Md. with a mean age of 47.7 (range 30-64) years, 45% males; 2200 African Americans (59%) and 1522 whites (41%); 41% reported household incomes below the 125% poverty delimiter. RESULTS: There were no significant age differences associated with sex or race. Participants below the 125% poverty delimiter were slightly younger than those above the delimiter. Age, race, and sex, but not poverty status, were associated with the likelihood of a physical examination. Older participants, women, and Whites were more likely to complete their examinations. Among those who completed their examinations, there were no age differences associated with sex and poverty status, but African Americans were negligibly younger than Whites. CONCLUSIONS: Although some literature suggests that minorities and low-income people are less willing to participate in clinical research, these baseline data suggest that African Americans individuals and individuals from households with incomes below 125% of the poverty level are at least as willing to participate in observational clinical studies as Whites and higher income individuals of similar age and sex.

Hierarchical cluster analysis of polychlorinated dioxins and furans in Michigan, USA, soils: evaluation of industrial and background congener profiles.

As part of the University of Michigan Dioxin Exposure Study, soil samples were collected from 766 residential properties near the Tittabawassee River between Midland and Saginaw; near the Dow Chemical Facility in Midland; and, for comparison, in the other areas of Midland and Saginaw Counties and in Jackson and Calhoun Counties, all located in the state of Michigan, USA. A total of 2,081 soil samples were analyzed for 17 polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). In order to better understand the distribution and sources of the PCDD/F congeners in the study area, hierarchical cluster analysis (HCA) was used to statistically group samples with similar congener patterns. The analysis yielded a total of 13 clusters, including: 3 clusters among the soils impacted by contamination present in the Tittabawassee River sediments, a cluster comprised mainly of samples collected within the depositional area of the Dow incinerator complex, a small cluster of samples with elevated 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD), and several clusters exhibiting background patterns. The clusters related to the Tittabawassee River floodplain contamination all contained elevated PCDF levels and were differentiated from one another primarily by their relative concentrations of higher-chlorinated PCDDs, a difference likely related to both extent and timing of impacts from Tittabawassee sediments. The background clusters appear to be related to combustion processes and are differentiated, in part, by their relative fractions of TCDD. Thus, HCA was useful for identifying congener profile characteristics in both contaminated and background soil samples.

Attitudes of pregnant women towards participation in perinatal epidemiological research.

We assessed attitudes of a multi-ethnic sample of pregnant women in regard to participation in five data collection procedures planned for use in the National Children's Study. A cross-sectional survey was conducted in nine prenatal clinics in Kent County, Michigan between April and October 2006. Women were approached in clinic waiting rooms at the time of their first prenatal visit and 311 (91.0%) participated. Women were asked about their willingness to participate, and the smallest amount of compensation required for participation in a 45-min in-person interview, a 15-min telephone interview, maternal and infant medical record abstraction, and an infant physical examination. Percentages for willingness to participate were highest for telephone interview (83%), followed by in-person interview (60%), infant examination (57%), and maternal (56%) and infant medical records (54%). About 34-48% of women reported that no compensation would be required for participation by data procedure. Some women reported unwillingness to participate in telephone (9%) or personal (17%) interview, record abstraction (34%) or infant examination (26%), even with compensation. Education greater than high school was associated with increased odds of refusal for infant physical examination, adjusted odds ratio 2.44 [95% confidence interval 1.41, 4.23]. In conclusion, 9-34% of pregnant women, depending on procedure, stated they would not participate in non-invasive research procedures such as medical record abstraction and infant examination, even with compensation. Resistance to these research procedures was especially noted among more highly educated women. Planning for the National Children's Study will have to address potential resistance to research among pregnant women.

An investigation of homes with high concentrations of PCDDs, PCDFs, and/or dioxin-like PCBs in house dust.

As part of the University of Michigan Dioxin Exposure Study, the 29 congeners of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls that have World Health Organization consensus toxic equivalency factors were measured in house dust from 764 homes using a population-based sampling design over selected regions in five Michigan counties. Twenty homes had a total toxic equivalency in house dust that was more than 2.5 standard deviations above the mean (i.e., defined to be outliers). This follow-up investigation describes the outlier house dust measurements and corresponding soil measurements and explores possible sources of these toxins in house dust. The congener distributions in the house dust outliers varied and were dominated (i.e., >50% of the total toxic equivalency) by either polychlorinated dibenzo-p-dioxins (n = 9), polychlorinated dibenzofurans (n = 1), or dioxin-like polychlorinated biphenyls (n = 9). Likely sources of contamination of house dust were identified in only three cases. In two cases, dust contamination appeared to be related to contaminated soil adjacent to the home; in one case, contamination was related to a source within the home (a carpet pad). In most cases, the source(s) of contamination of house dust could not be identified but appeared likely to be related to uncharacterized sources within the homes.

Case report: human exposure to dioxins from clay.

CONTEXT: For the general population, the dominant source of exposure to dioxin-like compounds is food. As part of the University of Michigan Dioxin Exposure Study (UMDES), we measured selected polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) in serum of 946 subjects who were a representative sample of the general population in five Michigan counties. CASE PRESENTATION: The total toxic equivalency (TEQ; based on 2005 World Health Organization toxic equivalency factors) of serum from the index case was 211 ppt on a lipid-adjusted basis, which was the highest value observed in the UMDES study population. This subject had no apparent opportunity for exposure to dioxins, except that she had lived on property with soil contaminated with dioxins for almost 30 years, and had been a ceramics hobbyist for > 30 years. Soil from her property and clay that she used for ceramics were both contaminated with dioxins, but the congener patterns differed. DISCUSSION: The congener patterns in this subject's serum, soil, and ceramic clay suggest strongly that the dioxin contamination in clay and not soil was the dominant source of dioxin contamination in her serum. RELEVANCE TO PUBLIC HEALTH PRACTICE: It appears that ceramic clay, in particular the process of firing clay with unvented kilns, can be a significant nonfood and nonindustrial source of human exposure to dioxins among ceramics hobbyists. The extent of human exposure from ceramic clay is unclear, but it may be widespread. Further work is needed to more precisely characterize the routes of exposure.

Estimating regression standard errors with data from the Current Population Survey's public use file.

This study examines whether reasonable standard errors for multivariate models can be calculated using the public use file of the Current Population Survey's Annual Social and Economic Supplement (CPS ASEC). We restrict our analysis to the 2003 CPS ASEC and model three dependent variables at the individual level. income, poverty, and health insurance coverage. We compare standard error estimates performed on the CPS ASEC public use file with those obtained from the Census Bureau's restricted internal data that include all the relevant sampling information needed to compute standard errors adjusted for the complex survey sample design. Our analysis shows that the multivariate standard error estimates derived from the public use CPS ASEC following our specification perform relatively well compared to the estimates derived from the internal Census Bureau file. However, it is essential that users of CPS ASEC data do not simply choose any available method since three of the methods commonly used for adjusting for the complex sample design produce substantially different estimates.

Determinants of dental care visits among low-income African-American children.

BACKGROUND: The objective of the authors' analysis was to investigate the determinants of dental care visits among young, low-income African-American children. METHODS: Trained researchers interviewed a representative sample of low-income black families (caregivers and children aged 0 through 5 years) in Detroit to assess their dental visit history, dental insurance status and oral health behaviors. Dental examinations were conducted using the International Caries Diagnosis Assessment System (ICDAS). Of the 1,021 families who completed an interview and examination, a subset of the 552 children aged 3 to 5 years (and their primary caregivers) was the focus of this analysis. RESULTS: Children with private dental insurance had four times higher odds of having visited a dentist compared with those who had no dental insurance, and the odds for children receiving Medicaid were about 1.5 times higher. A child's age and a caregiver's educational attainment were positive and significant determinants of child dental visits. Caregivers who visited a dentist for preventive reasons were five times more likely to have taken their children to visit the dentist. Visiting a dentist was associated with an increased mean number of filled or missing tooth surfaces, but it was not significantly associated with the mean number of untreated decayed teeth. CONCLUSION: Children's dental insurance status was a significant determinant of their having visited a dentist. Even after the authors accounted for insurance status and other risk indicators, they found that children of caregivers who reported visiting a dentist for preventive care had a higher number of dental care visits. Determinants of caregivers' preventive dental visits must be identified and encouraged to improve the percentage of low-income children who visit dentists.

Percentage and severity of periodontal diseases in Turkish adults aged 35+ years, 2009-10.

OBJECTIVE: This article presents data on the burden of periodontal diseases in Turkish adults aged 35 years or older. METHODS: Within each region of Turkey, a rural and an urban area or city were selected in 2009-10 using a probability proportional to size method. In the selected towns, local officials who were familiar with their communities assisted in recruiting subjects. Loss of Attachment (LOA) was measured at six sites around each tooth present in the mouth, excluding third molars. Additionally, the Community Periodontal Index was used to assess the severity of periodontal diseases around 12 index teeth. Self-reported data on key risk factors were also collected. Weights were computed using a raking ratio adjustment procedure and used in all analyses. RESULTS: Almost all examined adults had some loss of periodontal attachment. The proportion of those with more than 3 mm LOA ranged from 43 percent in 35-44 year olds to 91 percent in those aged 65+ years. Among females, older age, low education status, smoking 11-40+ cigarettes a day, being employed, and presence of high number of missing tooth surfaces were associated with LOA > 3 mm. Among males LOA >3 mm was associated with older age, use of alcohol, and unemployment. The CPI data did not yield the same associations with periodontal diseases and risk factors. CONCLUSIONS: Periodontal diseases in Turkish adults are highly prevalent. A tailored common risk factor health promotion program is recommended to reduce the burden of periodontal infection in Turkey.

Psychological distress among Ugandan adolescents living with HIV: Examining stressors and the buffering role of general and religious coping strategies.

HIV infection increases the risk of psychological distress among adolescents living with HIV (ALHIV), which, in turn, increases risky behaviours such as medication non-adherence, substance use, and sexual risk-taking. The majority of studies on psychological distress among ALHIV have been conducted in high-income countries; data on the prevalence and correlates of psychological distress among ALHIV in sub-Saharan Africa (SSA) are scarce, yet over two-thirds of the global population of ALHIV resides in SSA. The purpose of this study was to identify the contextually relevant correlates of psychological distress among Ugandan ALHIV. Utilizing the stress and coping framework, we explored the risk and protective factors for psychological distress in cross-sectional sample of 464 ALHIV (aged 12-19; 53% female) at a large HIV treatment centre in Kampala, Uganda. The stressors associated with psychological distress included daily hassles, major negative life events, HIV-related quality of life, and stigma. Protective factors included psychosocial resources such as religious coping, satisfaction with social support, and general coping style and behaviours. Social support and optimism were significantly associated with psychological distress. Findings underscore the need for mental health services for ALHIV in Uganda and other resource-limited settings.

Perceptions of alcohol-impaired driving and the blood alcohol concentration standard in the United States.

INTRODUCTION: Although the number of alcohol-impaired driving (AID) fatalities has declined over the past several years, AID continues to be a serious public health problem. The purpose of this effort was to gain a better understanding of the U.S. driving population's perceptions and thoughts about the impacts of lowering the blood alcohol concentration (BAC) driving standard below.08% on AID, health, and other outcomes. METHODS: A questionnaire was administered to a nationally representative sample of licensed drivers in the U.S. (n=1011) who were of age 21 or older on driving habits, alcohol consumption habits, drinking and driving habits, attitudes about drinking and driving, experiences with and opinions of drinking and driving laws, opinions about strategies to reduce drinking and driving, general concerns about traffic safety issues, and demographics. RESULTS: One-third of participants supported lowering the legal BAC standard, and participants rated a BAC standard of .05% to be moderately acceptable on average. 63.9% indicated that lowering 30 the BAC to .05% would have no effect on their decisions to drink and drive. Nearly 60% of respondents lacked accurate knowledge of their state's BAC standard. CONCLUSIONS: Public support for lowering the BAC standard was moderate and was partially tied to beliefs about the impacts of a change in the BAC standard. The results suggest that an opportunity for better educating the driving population about existing AID policy and the implications for lowering the BAC level on traffic injury prevention. PRACTICAL APPLICATIONS: The study results are useful for state traffic safety professionals and policy makers to have a better understanding of the public's perceptions of and thoughts about BAC standards. There is a clear need for more research into the effects of lowering the BAC standard on crashes, arrests, AID behavior, and alcohol-related behaviors.

National Survey of Family Growth, Cycle 6: sample design, weighting, imputation, and variance estimation.

OBJECTIVES: Cycle 6 of the National Survey of Family Growth (NSFG) was conducted by the National Center for Health Statistics in 2002 and early 2003. This report describes how the sample was designed, shows response rates for various subgroups of men and women, describes how the sample weights were computed to make national estimates possible, shows how missing data were imputed for a limited set of key variables, and describes the proper ways to estimate sampling errors from the NSFG. The report includes both nontechnical summaries for readers who need only general information and more technical detail for readers who need an in-depth understanding of these topics. METHODS: The NSFG Cycle 6 was based on an independent, national probability sample of men and women 15-44 years of age. It was the first NSFG ever to include a national sample of men 15-44 as well as a sample of women. Fieldwork was carried out by the University of Michigan's Institute for Social Research (ISR) under a contract with NCHS. In-person, face-to-face interviews were conducted by professional female interviewers using laptop computers. In all, 12,571 women and men-7,643 females and 4,928 males-were interviewed, the largest NSFG ever done. RESULTS: Analysis of NSFG Cycle 6 data requires the use of sampling weights and estimation of sampling errors that accounts for the complex sample design and estimation features of the survey. Examples of how to use several available software packages that incorporate complex design features in estimation, such as SAS, SUDAAN, and STATA, are presented.