James M. Lepkowski

The social stratification of aging and health

The way health varies with age is importantly stratified by socioeconomic status (SES)--specifically, education and income. Prior theory and cross-sectional data suggest that among higher SES persons the onset of health problems is usually postponed until rather late in life, while health declines are prevalent in lower SES groups by middle age. Thus, SES differences in health are small in early adulthood, but increase with age until relatively late in life, when they diminish due to selection or greater equalization of health risks and protections. The present paper strengthens our causal and interpretive understanding of these phenomena by showing: (1) that results previously reported for indices of SES hold separately for education and income; (2) that the interaction between age and SES (i.e., education or income) in predicting health can be substantially explained by the greater exposure of lower SES persons to a wide range of psychosocial risk factors to health, especially in middle and early old age, and, to a lesser degree, the greater impact of these risk factors on health with age; and (3) that results (1) and (2) generally hold in short-term longitudinal as well as in cross-sectional data. Implications for science and policy in the areas of aging, health, and social stratification are discussed.

Social and Physical Environments and Disparities in Risk for Cardiovascular Disease: The Healthy Environments Partnership Conceptual Model

The Healthy Environments Partnership (HEP) is a community-based participatory research effort investigating variations in cardiovascular disease risk, and the contributions of social and physical environments to those variations, among non-Hispanic black, non-Hispanic white, and Hispanic residents in three areas of Detroit, Michigan. Initiated in October 2000 as a part of the National Institute of Environmental Health Sciences’ Health Disparities Initiative, HEP is affiliated with the Detroit Community–Academic Urban Research Center. The study is guided by a conceptual model that considers race-based residential segregation and associated concentrations of poverty and wealth to be fundamental factors influencing multiple, more proximate predictors of cardiovascular risk. Within this model, physical and social environments are identified as intermediate factors that mediate relationships between fundamental factors and more proximate factors such as physical activity and dietary practices that ultimately influence anthropomorphic and physiologic indicators of cardiovascular risk. The study design and data collection methods were jointly developed and implemented by a research team based in community-based organizations, health service organizations, and academic institutions. These efforts include collecting and analyzing airborne particulate matter over a 3-year period; census and administrative data; neighborhood observation checklist data to assess aspects of the physical and social environment; household survey data including information on perceived stressors, access to social support, and health-related behaviors; and anthropometric, biomarker, and self-report data as indicators of cardiovascular health. Through these collaborative efforts, HEP seeks to contribute to an understanding of factors that contribute to racial and socioeconomic health inequities, and develop a foundation for efforts to eliminate these disparities in Detroit.

American adolescents: sexual mixing patterns, bridge partners, and concurrency.

Background American adolescents have a high incidence of sexually transmitted infections. Patterns of sexual partner choice influence the transmission of infections in this population. Goal To examine patterns of sexual mixing, bridging, and concurrency in American adolescents and the association of these characteristics with condom use. Study Design This project used the AddHEALTH survey data. The survey selected a sample of schools, then conducted in-home interviews with 18,984 students in 1995. A second wave of data collection was conducted 2 years later. The data on sexual relationships collected in the study were analyzed. Results Respondents ranged in age from 13 to 17 years. Sex partnerships with persons of differing age groups were very common in this population (45% of sexual partnerships). Relationships with persons of different ethnicity were more common among Latinos (42%) than among white (14%) and black (15%) respondents. A large proportion of the sample reported more than two partners (56%). Among these persons, a large proportion reported partners in two different age groups (69%) and ethnic groups (35%) as well as concurrent partners (54%). Condom use was lower among persons with partners in different age groups and among persons with a larger number of partners. Conclusions The large number of adolescents who have sexual relationships with persons of different characteristics creates bridges for infections between different groups. Counseling of sexually active adolescents should include discussion on issues of power and communication in these relationships.

Risk indicators for dental caries using the International Caries Detection and Assessment System (ICDAS)

BACKGROUND While national surveys have found that African-Americans have a higher prevalence and severity of dental caries than white-Americans, there are only a few descriptive studies of the prevalence and severity of dental caries in low-income urban African-Americans. OBJECTIVES This study assessed the prevalence, severity and determinants of dental caries, using the International Caries Detection and Assessment System (ICDAS). METHODS A representative sample of low-income families (a caregiver and a child aged 0-5 years) was selected from low-income census tracts in the city of Detroit, Michigan. Of the 12,655 randomly selected housing units, 10,695 were occupied and 9781 were successfully contacted (91.5%). There were 1386 families with eligible children in the contacted households; and of those, 1021 were interviewed and examined at a permanent examination center organized for this study. This represents an overall response rate of 73.7%. At the center, trained staff interviewed the main caregivers of the selected children, and trained and calibrated dentists examined the caregiver and her/his child. Data used in this study included information gathered from the social, behavioral and parenting questionnaires, the Block Food Frequency Questionnaire (total sugar intake), and data collected from community and census databases. RESULTS Over 90% of the adults (ages 14-70 years, average 29.3) had at least one noncavitated carious lesion and 82.2% had at least one primary cavitated lesion. Negative binomial regression models found that the age of caregivers and the number of churches in neighborhoods were negatively associated with the number of noncavitated tooth surfaces. Cavitated tooth surfaces were positively associated with age, oral hygiene status, being worried about teeth, a recent visit to a dentist, and the number of grocery stores in the neighborhoods. However, the number of cavitated tooth surfaces was negatively associated with preventive dental visits, positive rating of oral health status and the number of dentists in a community. CONCLUSIONS Dental caries, especially at the noncavitated stage, is highly prevalent in low-income African-American adults in Detroit. A significant increase in the mean number of missing teeth was observed after the age of 34 years. This study found that different individual, social, and community risk indicators were associated with noncavitated versus cavitated tooth surfaces.

EFFECTS OF A PREPAID NONMONETARY INCENTIVE ON RESPONSE RATES AND RESPONSE QUALITY IN A FACE-TO-FACE SURVEY

We conducted a randomized experiment on a face-to- face interview survey in order to test the effects on response rates of a prepaid nonmonetary incentive. Results showed a sta- tistically significant increase in response rates, mostly through reduction in refusal rates, in the half sample that received the incentive (a gift-type ballpoint pen) as compared with a no incen- tive control group. The effect appears to be due to greater cooper- ation from incentive recipients at the initial visit by an inter- viewer. Unexpectedly, the incentive group also showed a significantly higher rate of sample ineligibility, possibly due to easier identification of vacant residences or nonexistent ad- dresses. In addition, evidence suggests greater response com- pleteness among responding incentive recipients early in the in- terview, with no evidence of increased measurement error due

Obesity and Sugar‐sweetened Beverages in African‐American Preschool Children: A Longitudinal Study

A representative sample of 365 low‐income African‐American preschool children aged 3–5 years was studied to determine the association between sugar‐sweetened beverage consumption (soda, fruit drinks, and both combined) and overweight and obesity. Children were examined at a dental clinic in 2002–2003 and again after 2 years. Dietary information was collected using the Block Kids Food Frequency Questionnaire. A BMI score was computed from recorded height and weight. Overweight and obesity were defined by national reference age‐sex specific BMI: those with an age‐sex specific BMI ≥85th, but <95th percentile as overweight and those with BMI ≥95th age‐sex specific percentile as obese. The prevalence of overweight was 12.9% in baseline, and increased to 18.7% after 2 years. The prevalence of obesity increased from 10.3 to 20.4% during the same period. Baseline intake of soda and all sugar‐sweetened beverages were positively associated with baseline BMI z‐scores. After adjusting for covariates, additional intake of fruit drinks and all sugar‐sweetened beverages at baseline showed significantly higher odds of incidence of overweight over 2 years. Among a longitudinal cohort of African‐American preschool children, high consumption of sugar‐sweetened beverages was significantly associated with an increased risk for obesity.

Excess mortality among urban residents: how much, for whom, and why?

OBJECTIVES The goals of this study were to estimate prospective mortality risks of city residence, specify how these risks vary by population subgroup, and explore possible explanations. METHODS Data were derived from a probability sample of 3617 adults in the coterminous United States and analyzed via cross-tabular and Cox proportional hazards methods. RESULTS After adjustment for baseline sociodemographic and health variables, city residents had a mortality hazard rate ratio of 1.62 (95% confidence interval [CI] = 1.21, 2.18) relative to rural/small-town residents; suburbanites had an intermediate but not significantly elevated hazard rate ratio. This urban mortality risk was significant among men (hazard rate ratio: 2.25), especially non-Black men, but not among women. Among Black men, and to some degree Black women, suburban residence carried the greatest risk. All risks were most evident for those younger than 65 years. CONCLUSIONS The mortality risk of city residence, at least among men, rivals that of major psychosocial risk factors such as race, low income, smoking, and social isolation and merits comparable attention in research and policy.

Characteristics of sexual partners and STD infection among American adolescents

Adolescents are a high risk group for HIV infection and the characteristics of their partners may affect their susceptibility to infection. The goal of this study was to examine the effects of partner characteristics on sexually transmitted disease (STD) infection in a national sample of adolescents. Data from 8,024 sexually active adolescents who participated in the National Longitudinal Study of Adolescent Health (Add Health) in the United States were included in this study. Logistic models were used to examine the association of partner characteristics including age, neighbourhood, ethnicity, and school attendance on the self-report history of STD infection. The partner characteristics of age and school attendance were associated with the reporting of STD infection. The odds ratio for STD infection was 1.46 (95% confidence interval (CI) (1.22-1.75), P < 0.01) if the adolescents partner was two or more years older and 1.37 (95% CI (1.16-1.62), P < 0.01) if the partner did not attend the adolescents school. The odds ratios for having an older partner were also significant and positive for eight different STDs. Partner characteristics were associated with STD infection among American adolescents. Counselling is needed in clinics that serve adolescents to raise awareness of the risk of infection in these relationships and to improve skills in condom negotiation and use.

The Current Efficiency of List-Assisted Telephone Sampling Designs

List-assisted random digit dialing (RDD) designs became popular in the late 1980s and early 1990s. Work done by the Bureau of Labor Statistics and the University of Michigan in 1993 resulted in the development of the underlying theory for these designs as well as the evaluation of various alternative sampling plans to optimize the method. Recent research to reevaluate these designs in light of the significant changes in the telephone system over the past decade is presented in this article. The article provides background on the development of list-assisted designs, and recent changes in the U.S. telephone system are reviewed. Using 1999 data from Survey Sampling, Inc., an analysis of the current state of the telephone system is presented, and a reoptimization of the earlier designs is undertaken. Results from the earlier work are compared with findings from the 1999 data.

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/√2. 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/√2 for values below the LOD, assuming a known parametric distribution, or using imputation to replace the left-censored values.