Using aggregate geographic data to proxy individual socioeconomic status: does size matter?

OBJECTIVES: This study assessed whether aggregate-level measures of socioeconomic status (SES) are less biased as proxies for individual-level measures if the unit of geographic aggregation is small in size and population. METHODS: National Health Interview Survey and census data were used to replicate analyses that identified the degree to which aggregate proxies of individual SES bias interpretations of the effects of SES on health. RESULTS: Ordinary least squares regressions on self-perceived health showed that the coefficients for income and education measured at the tract and block group levels were larger than those at the individual level but smaller than those estimated by Geronimus et al. at the zip code level. CONCLUSIONS: Researchers should be cautious about use of proxy measurement of individual SES even if proxies are calculated from small geographic units.

The effect of income inequality on the health of selected US demographic groups.

OBJECTIVES: This study assessed whether documented effects of income inequality on health are consistent across demographic subgroups of the US population. METHODS: Data from the National Health Interview Survey on White and Black non-Hispanics were used. Logistic regression models were estimated with SUDAAN software. Perceived health was the outcome variable. RESULTS: The results of the multivariate analysis, in which individual family income and county-level poverty rates were included, were not consistent with existing research. In the presence of covariates, the conditional effects of inequality were restricted to Whites aged 18-44 years in the 2 highest income inequality quartiles and middle-aged Whites in counties with the highest level of income inequality. The health of Blacks of all ages, elderly Whites, and middle-aged Whites outside of the areas of highest inequality was unaffected when controls for individual characteristics and county-level poverty were in place. CONCLUSIONS: For the United States, the independent and direct contribution of income inequality to the determination of self-perceived health net of individual income and county income levels is restricted to certain demographic groups.

Socioeconomic status and injury mortality: individual and neighbourhood determinants.

STUDY OBJECTIVE: This study examined both individual and neighbourhood correlates of injury mortality to better understand the contribution of socioeconomic status to cause specific injury mortality. Of particular interest was whether neighbourhood effects remained after adjusting for individual demographic characteristics and socioeconomic status. DESIGN: Census tract data (measuring small area socioeconomic status, racial concentration, residential stability, urbanisation, and family structure) was merged with the National Health Interview Survey (NHIS) and a file that links the respondents to subsequent follow up of vital status and cause of death data. Cox proportional hazards models were specified to determine individual and neighbourhood effects on homicide, suicide, motor vehicle deaths, and other external causes. Variances are adjusted for the clustered sample design of the NHIS. SETTING: United States, 1987-1994, with follow up to the end of 1995. PARTICIPANTS: From a sample of 472 364 persons ages 18-64, there were 1195 injury related deaths over the follow up period. MAIN RESULTS: Individual level effects were generally robust to the inclusion of neighbourhood level variables in the models. Neighbourhood characteristics had independent effects on the outcome even after adjustment for individual variability. For example, there was approximately a twofold increased risk of homicide associated with living in a neighborhood characterised by low socioeconomic status, after adjusting for individual demographic and socioeconomic characteristics. CONCLUSIONS: Social inequalities in injury mortality exist for both persons and places. Policies or interventions aimed at preventing or controlling injuries should take into account not only the socioeconomic characteristics of people but also of the places in which they live.

Socioeconomic status and the occurrence of fatal and nonfatal injury in the United States.

OBJECTIVES: This study examined the contribution of socioeconomic status (SES) to the risk of injury mortality and morbidity among working-age adults. METHODS: The sample consisted of respondents to the National Health Interview Survey (1987-1994), and separate analyses were conducted for injury deaths to respondents by linking to the National Death Index. Proportional hazards regression models were used to analyze mortality. Logistic regression models were used to analyze morbidity. RESULTS: The effects of SES varied substantially by cause of injury mortality and indicator of SES. In the multivariate models, blue-collar workers were at significantly increased odds of nonfatal injury. Education was unrelated to total injury morbidity, although associations were observed after stratification of the outcome by severity and place of occurrence. Black persons were at increased risk for homicide, and Black and Hispanic persons were at decreased risk for suicide and nonfatal injuries, after adjustment for SES. CONCLUSIONS: SES is an important determinant of injury, although the effect depends on the indicator of SES and the cause and severity of injury.

Aggregation and the measurement of income inequality: effects on morbidity.

This is a cross-sectional study using records from the National Health Interview Survey linked to Census geography. The sample is restricted to white males ages 25-64 in the United States from three years (1989-1991) of the National Health Interview Survey. Perceived health is used to measure morbidity. Individual covariates include income-to-needs ratio, education and occupation. Contextual level measures of income inequality, median household income and percent in poverty are constructed at the US census county and tract level. The association between inequality and morbidity is examined using logistic regression models. Income inequality is found to exert an independent adverse effect on self-rated health at the county level, controlling for individual socioeconomic status and median income or percent poverty in the county. This corresponding effect at the tract level is reduced. Median income or percent poverty and individual socioeconomic status are the dominant correlates of perceived health status at the tract level. These results suggest that the level of geographic aggregation influences the pathways through which income inequality is actualized into an individuals' morbidity risk. At higher levels of aggregation there are independent effects of income inequality, while at lower levels of aggregation, income inequality is mediated by the neighborhood consequences of income inequality and individual processes.

Neighborhood social context and racial differences in women's heart disease mortality.

Compared to white women, black women experience similar rates of heart disease morbidity, but higher rates of heart disease mortality. This puzzling relationship may be due to several factors working at varied levels to affect each race. For example, the high heart disease mortality rate may be due to individual health or socioeconomic risk factors or to social structural factors. We conduct a multi-level analysis to address these issues, using data from a newly released data file that links the National Health Interview Survey with death certificate information from the National Death Index, and with additional community level data from the 1990 Census STF-3A files. We are primarily interested in the effects of female-headship rates in the census tracts on coronary heart disease mortality (CHD) among black and white women. We find that women who live in communities with high concentrations of female-headed families are more likely to die of heart disease, net of other characteristics. For younger women, the effect appears to be routed primarily through poverty whereas for older women the effect of female-headship rates remains, net of other census tract characteristics. This study, then, highlights the importance of examining the effect of neighborhoods and their social content on mortality.

Smoking behavior of recent mothers, 18-44 years of age, before and after pregnancy: United States, 1990.

OBJECTIVE: This report presents a comprehensive review of data on the smoking behaviors of women with a recent birth from the 1990 National Health Interview Survey. Data on current and lifetime smoking status and smoking behaviors before and after learning of pregnancy are presented. Selected demographic characteristics of women--including age, race, education, and family income--are also presented. METHODS: Data presented in this report are from the 1990 National Health Interview Survey on Health Promotion and Disease Prevention (NHIS-HPDP). Questions on pregnancy and smoking were administered as part of this supplement to women 18-44 years of age who either had a live birth in the 5 years preceding the interview, or who were pregnant at the time of the interview. These analyses were limited to women with a live birth in the 5 years preceding the 1990 NHIS who were not currently pregnant. RESULTS: Of 13,674,000 women with a recent live birth, about 39 percent had ever smoked, 25 percent smoked in the year before they became pregnant, and 15 percent smoked during their most recent pregnancy. Women who smoked prior to learning of their pregnancy were most likely to be moderate smokers, white women, never married, and of lower income. Women who smoked after learning of their pregnancy were most likely to be light smokers, representing a shift in smoking behaviors after learning of pregnancy. Nearly 23 percent of women reported that they stopped smoking altogether after learning of their pregnancy. CONCLUSIONS: These findings are consistent with data from other sources and provide support for recently observed trends in smoking and pregnancy. A majority of women who had ever smoked continued to smoke throughout pregnancy. Although many women altered their smoking behaviors, only about one quarter of women reported that they stopped smoking entirely. Public health service messages must continue to encourage women to stop smoking entirely during pregnancy to maximize the health benefits to their infants.

Health and selected socioeconomic characteristics of the family: United States, 1988-90.

National estimates of average annual health indexes for the civilian noninstitutionalized population of the United States are presented in this report according to selected socioeconomic characteristics of the family. These estimates are based on data from the National Health Interview Survey (NHIS) in 1988, 1989, and 1990. Health indexes presented include percent limited in activity; percent with fair or poor respondent-assessed health status, restricted activity days, bed disability days, work-loss days, and school-loss days; percent with a physician contact in past year; numbers of annual physician contacts per person per year; percent with a hospital episode in the past year; days per short-term hospital stay; and incidence of acute conditions. This report includes the findings that persons living by themselves reported a higher percent of limitations in activity, high rates of disability days, more physician contacts per year, and a higher incidence rate from acute conditions than all persons 45-64 years of age. Persons in all four age groups reported higher percents with limitations of activity and higher percents with fair or poor health status in families in which the educational level of the responsible family adult member was less the 12 years than in families where the responsible adult was better educated. Both males and females, and white persons and black persons, in each of the age groups 18 years and over who were living with a spouse reported lower percents of limitations in activity than did persons living in other family relationships.

Health care utilization, family context, and adaptation among immigrants to the United States.

We use the 1990 National Health Interview Survey supplement on Family Resources to examine the health care utilization patterns of immigrant and native-born adults in the United States. We modify a standard health care utilization framework by including duration of residence in the United States and measures of immigrant adaptation and family health context to model both the probability and number of physician contacts in the previous year. We find that duration of residence has a strong effect. Recently-arrived immigrants are much less likely to have had a contact in the previous year and had fewer contacts than either native-born or longer-term immigrant adults. Once the measures of adaptation--age at immigration and language of survey interview--are included, immigrants who have been in the United States for 10 years or more are not statistically different from the native-born. Family characteristics, including measures of exposure to the formal health care system, slightly reduce the size of the effects but do not alter the basic relationship between duration of residence and health care utilization. These results suggest that, net of socioeconomic characteristics, access to health insurance, and differences in morbidity, recent immigrants are much less likely than both the native-born and those immigrants of longer duration, to receive timely health care.

National study of knowledge of AIDS, testing patterns, and self-assessed risk among health care workers.

We conducted a study to assess the level of AIDS knowledge, testing behavior patterns, and self-assessed risk of contracting AIDS for a representative sample of health care workers in the United States. The study was based on data collected in the 1989 AIDS Knowledge and Attitudes Supplement to the National Health Interview Survey. Health care workers in four occupational groups were compared with other members of the labor force and with one another. The survey included 1,620 respondents identified as health care workers and 25,217 respondents with occupations other than in health care. Health care workers were more knowledgeable about AIDS than were other workers; approximately 55% and 25%, respectively, reported knowing a lot about AIDS. They were also more likely to have been tested (34%) than other workers (24%) and to have done so voluntarily (28% versus 14%). Health care workers also believed they had higher risk of contracting AIDS (8% versus 3%), although they were about equally likely to report being in one of the six high-risk groups. Among health care workers, those in the health diagnosing occupations were the most knowledgeable about AIDS (74% reported knowing a lot) and were the most likely to have been tested (41% were tested at least once). Health service workers were the least knowledgeable; only 38% reported knowing a lot about AIDS and only 26% reported being tested.

Household extension and reproductive behaviour in Taiwan.

PIP: The inflence of household type on reproductive behavior is examined for a national probability sample of Taiwanese women. Data were derived from a 1980 national household survey of the labor force in Taiwan, focusing on 10,624 couples. Reproductive variables include measures of current and prospective fertility as well as cumulative fertility. In spite of remarkable social and economic development over the past 3 decades, extended families are still widely found in Taiwan. Women in extended households have only slightly higher fertility preferences and current fertility than women in nuclear families once marital duration is controlled. Although women in extended households marry earlier and receive more family help with child care than women in nuclear families, such factors are no longer considered sufficient to produce major differentials in reproductive behavior. Residence and husband's class of work are the strongest correlates of whether a household is currently extended or nuclear. In general, the husband's characteristics are more strongly related to family type than the wife's. Findings suggest that preferences for smaller families and low fertility need not await a transformation to a nuclear family structue.^ieng