Constructing Weights to Use in Analyzing Pairs of Individuals from Add Health Data

Investigating certain research questions may involve linking the responses of one adolescent to those of another adolescent interviewed in the Add Health Survey. The goal of the analysis will be to characterize the behavior of a pair of adolescents rather than the behavior of an individual adolescent . Unfortunately, the available sampling weights are appropriate only when the analysis seeks to investigate behaviors of individual adolescents. However, an appropriate sampling weight can be constructed for each pair of adolescents and used to correct for clustering and unequal probability of selection of the pair. This paper covers the types of pairs of adolescents that can have a pair weight constructed, describes the necessary formulas and data, and concludes with an example showing how to compute pair weights for romantic partners from the Wave II In-home Interview

Guidelines for Analyzing Add Health Data

The National Longitudinal Study of Adolescent Health (Add Health) is a longitudinal study of a nationally representative sample of adolescents in grades 7-12 in the United States in 1994-95 that has been followed through adolescence and the transition to adulthood with four in-home interviews. The Add Health study design used a clustered sample in which the clusters were sampled with unequal probability. While reducing the cost of data collection, this design complicates the statistical analysis because the observations are no longer independent and identically distributed. To analyze the data correctly requires the use of special survey software packages specifically designed to handle observations that are not independent and identically distributed. The purpose of this document is to provide guidelines to correctly analyze the Add Health data. To do this, we describe the characteristics of the Add Health sample design and data elements needed by the survey software packages. We next identify a series of common errors to avoid when analyzing the Add Health data. Lastly, we provide examples of different types of analysis using various survey software packages

Non-Response in Wave III of the Add Health Study

Non-response is a potential threat to the accuracy of estimates obtained from sample surveys and can be particularly difficult to avoid in longitudinal studies. The purpose of this report is to investigate non-response in Wave III of Add Health and its influence on study results. Non-response in earlier waves of Add Health has been investigated by the Survey Research Unit at the University of North Carolina. Findings showed that total bias for 13 measures of health and risk behaviors rarely exceed 1% in either Wave I or Wave II, which is small relative to the 20% to 80% prevalence rates for most of these measures. In the following section, we present an overview of the Wave III sampling plan and results of the field work. Next, we characterize the non-response found in the original sampling variables. We then take advantage of the longitudinal design of Add Health to estimate total and relative bias on demographics and a variety of health and risk behaviors reported by both non-responders and responders during their Wave I In-home Interview. We conclude with a discussion of how the bias caused by non-response can be minimized during future waves of data collection

Does Framing Human Papillomavirus Vaccine as Preventing Cancer in Men Increase Vaccine Acceptability?

Human papillomavirus (HPV) vaccine is now approved for use in males in the United States to prevent genital warts. We conducted an experiment to see whether framing HPV vaccination as also preventing cancer in men would increase men’s vaccination willingness

Predictors of pregnancy and postpartum haemoglobin concentrations in low-income women

OBJECTIVE: Pregnancy and postpartum iron status is of great public health importance, yet few studies have examined predictors of haemoglobin (Hb) concentration during this time. We identified predictors of Hb from 24 weeks' gestation until delivery and from 4 to 25 weeks postpartum. DESIGN: Blood was drawn as many as four times during care: at the initial visit, at 24-29 weeks' gestation, at delivery and postpartum. A longitudinal, multivariable linear regression model was used to predict Hb concentration. SETTING: A public health clinic in Raleigh, North Carolina. SUBJECTS: n=520 women who participated in the Iron Supplementation Study. RESULTS: Hb concentration at the previous blood draw, short stature, non-Hispanic white ethnicity/race, >12 years of education and smoking were positive predictors of pregnancy and postpartum Hb concentrations. Iron supplement use was a positive predictor, while inadequate weight gain and severe nausea/vomiting were negative predictors of gestational Hb. A high infant birth weight and postpartum haemorrhage were negative predictors of postpartum Hb. Pre-pregnancy body mass index had a slight positive relationship with gestational Hb, but had a strong negative relationship with postpartum Hb. The longitudinal model also confirmed the typical pattern of gestational Hb concentration. As the number of weeks between the initial visit and the 24- to 29-week visit increased, Hb at 24-29 weeks' gestation decreased. As gestational age increased from 24 weeks until delivery, Hb concentration increased as well. CONCLUSIONS: The predictors identified here could be used in clinical settings to target high-risk women for intervention

Improving Human Papillomavirus Vaccine Delivery: A National Study of Parents and Their Adolescent Sons

We examined parents’ and adolescents’ preferences regarding potential strategies to increase HPV vaccination rates, including offering the vaccine in alternative settings, concomitant administration of vaccines, and optimizing the structure of vaccination medical visits

Determinants of Usual Source of Care Disparities among African American and Caribbean Black Men: Findings from the national Survey of american life

Purpose—The Aday-Andersen model was used as a framework for investigating the contribution of immigration status (i.e., nativity and acculturation), socioeconomic factors, health care access, health status, and health insurance to usual source of health care (USOC) in a nationally representative sample of African American (n5551) and Caribbean Black men (n51,217). Methods—We used the 2001–2003 National Survey of American Life, a nationally representative household survey of non-institutionalized U.S. Blacks to conduct descriptive and logistic regression analyses. Results—Older age, more health conditions, neighborhood medical clinic access, and health insurance were associated with higher odds of reporting a USOC. Odds were lower for men with lower-middle incomes and poorer mental health status. Having health insurance was associated with higher odds of reporting a USOC for African American men but lower odds among Caribbean Black men. Odds were higher in the presence of more health conditions for African American men than for Caribbean Black men. Conclusions—Health care reform policies aimed solely at increasing health insurance may not uniformly eliminate USOC disparities disfavoring U.S. and foreign-born non-Hispanic Black men

The Association Between Maternal Glucose Concentration and Child BMI at Age 3 Years

OBJECTIVE—The objective of the study was to determine the association between child BMI at age 3 years and maternal glucose concentration among women without pre-existing diabetes or a gestational diabetes mellitus (GDM) diagnosis. RESEARCH DESIGN AND METHODS—Data are from the Pregnancy Infection and Nutrition and Postpartum studies and include 263 mother-child pairs. Measured weights and heights at 3 years were used to calculate age- and sex-specific BMIz scores and percentiles. Multivariable linear regression models were used to examine associations of continuous BMI z scores with maternal glucose concentration. Modified Poisson regression estimated risk ratios of child overweight/obesity (BMI $85th percentile). RESULTS—The mean (SD) maternal glucose concentration and prepregnancy BMI were 103.8 (23.7) mg/dL and 24.3 (5.9) kg/m 2, respectively. At 3 years, the mean (SD) child BMI z score was 0.29 (0.99), 20.9$130 mg/dL was associated with significantly higher child BMI z score at 3 years (estimated z scoredifferenceof0.39[95

Diuretic Exposure in Premature Infants from 1997 to 2011

Diuretics are often prescribed off-label to premature infants, particularly to prevent or treat bronchopulmonary dysplasia (BPD). We examined their use and safety in this group

A Repeat Random Survey of the Prevalence of Falsified and Substandard Antimalarials in the Lao PDR: A Change for the Better.

In 2003, a stratified random sample survey was conducted in the Lao People's Democratic Republic (Laos) to study the availability and quality of antimalarials in the private sector. In 2012, this survey was repeated to allow a statistically valid analysis of change through time. The counterfeit detection device 3 (CD-3) was used to assess packaging quality in the field and HPLC and mass spectroscopy analysis chemical analysis performed. The availability of oral artesunate monotherapies had significantly decreased from 22.9% (22) of 96 outlets in southern Laos in 2003 to 4.8% (7) of 144 outlets in 2012 (P < 0.0001). All the samples collected in the 2012 survey contained the correct active pharmaceutical ingredients (APIs) in contrast to the 21 (84%) falsified artesunate samples found in the 2003 survey. Although none of the medicines found in 2012 survey had evidence for falsification, 25.4% (37) of the samples were outside the 90-110% pharmacopeial limits of the label claim, suggesting that they were substandard or degraded. Results obtained from this survey show that patients are still exposed to poorly manufactured drugs or to ineffective medicines such as chloroquine. The quality of artemisinin-based combination therapies (ACTs) used in Laos needs to be monitored, since falsified ACTs would have devastating consequences in public health