A new tool for epidemiology: the usefulness of dynamic-agent models in understanding place effects on health

A major focus of recent work on the spatial patterning of health has been the study of how features of residential environments or neighborhoods may affect health. Place effects on health emerge from complex interdependent processes in which individuals interact with each other and their environment and in which both individuals and environments adapt and change over time. Traditional epidemiologic study designs and statistical regression approaches are unable to examine these dynamic processes. These limitations have constrained the types of questions asked, the answers received, and the hypotheses and theoretical explanations that are developed. Agent-based models and other systems-dynamics models may help to address some of these challenges. Agent-based models are computer representations of systems consisting of heterogeneous microentities that can interact and change/adapt over time in response to other agents and features of the environment. Using these models, one can observe how macroscale dynamics emerge from microscale interactions and adaptations. A number of challenges and limitations exist for agent-based modeling. Nevertheless, use of these dynamic models may complement traditional epidemiologic analyses and yield additional insights into the processes involved and the interventions that may be most useful.

Examining a bidirectional association between depressive symptoms and diabetes

CONTEXT

Depressive symptoms are associated with development of type 2 diabetes, but it is unclear whether type 2 diabetes is a risk factor for elevated depressive symptoms.

OBJECTIVE

To examine the bidirectional association between depressive symptoms and type 2 diabetes.

DESIGN, SETTING, AND PARTICIPANTS

Multi-Ethnic Study of Atherosclerosis, a longitudinal, ethnically diverse cohort study of US men and women aged 45 to 84 years enrolled in 2000-2002 and followed up until 2004-2005.

MAIN OUTCOME MEASURES

Elevated depressive symptoms defined by Center for Epidemiologic Studies Depression Scale (CES-D) score of 16 or higher, use of antidepressant medications, or both. The CES-D score was also modeled continuously. Participants were categorized as normal fasting glucose (< 100 mg/dL), impaired fasting glucose (100-125 mg/dL), or type 2 diabetes (> or = 126 mg/dL or receiving treatment). Analysis 1 included 5201 participants without type 2 diabetes at baseline and estimated the relative hazard of incident type 2 diabetes over 3.2 years for those with and without depressive symptoms. Analysis 2 included 4847 participants without depressive symptoms at baseline and calculated the relative odds of developing depressive symptoms over 3.1 years for those with and without type 2 diabetes.

RESULTS

In analysis 1, the incidence rate of type 2 diabetes was 22.0 and 16.6 per 1000 person-years for those with and without elevated depressive symptoms, respectively. The risk of incident type 2 diabetes was 1.10 times higher for each 5-unit increment in CES-D score (95% confidence interval [CI], 1.02-1.19) after adjustment for demographic factors and body mass index. This association persisted following adjustment for metabolic, inflammatory, socioeconomic, or lifestyle factors, although it was no longer statistically significant following adjustment for the latter (relative hazard, 1.08; 95% CI, 0.99-1.19). In analysis 2, the incidence rates of elevated depressive symptoms per 1000-person years were 36.8 for participants with normal fasting glucose; 27.9 for impaired fasting glucose; 31.2 for untreated type 2 diabetes, and 61.9 for treated type 2 diabetes. Compared with normal fasting glucose, the demographic-adjusted odds ratios of developing elevated depressive symptoms were 0.79 (95% CI, 0.63-0.99) for impaired fasting glucose, 0.75 (95% CI, 0.44-1.27) for untreated type 2 diabetes, and 1.54 (95% CI, 1.13-2.09) for treated type 2 diabetes. None of these associations with incident depressive symptoms were materially altered with adjustment for body mass index, socioeconomic and lifestyle factors, and comorbidities. Findings in both analyses were comparable across ethnic groups.

CONCLUSIONS

A modest association of baseline depressive symptoms with incident type 2 diabetes existed that was partially explained by lifestyle factors. Impaired fasting glucose and untreated type 2 diabetes were inversely associated with incident depressive symptoms, whereas treated type 2 diabetes showed a positive association with depressive symptoms. These associations were not substantively affected by adjustment for potential confounding or mediating factors.

Relation between neighborhood environments and obesity in the Multi-Ethnic Study of Atherosclerosis

This study investigated associations between neighborhood physical and social environments and body mass index in 2,865 participants of the Multi-Ethnic Study of Atherosclerosis (MESA) aged 45-84 years and residing in Maryland, New York, and North Carolina. Neighborhood (census tract) environments were measured in non-MESA participants residing in MESA neighborhoods (2000-2002). The neighborhood physical environment score combined measures of a better walking environment and greater availability of healthy foods. The neighborhood social environment score combined measures of greater aesthetic quality, safety, and social cohesion and less violent crime. Marginal maximum likelihood was used to estimate associations between neighborhood environments and body mass index (kg/m(2)) before and after adjustment for individual-level covariates. MESA residents of neighborhoods with better physical environments had lower body mass index (mean difference per standard deviation higher neighborhood measure = -2.38 (95% confidence interval (CI): -3.38, -1.38) kg/m(2) for women and -1.20 (95% CI: -1.84, -0.57) kg/m(2) for men), independent of age, race/ethnicity, education, and income. Attenuation of these associations after adjustment for diet and physical activity suggests a mediating role of these behaviors. In men, the mean body mass index was higher in areas with better social environments (mean difference = 0.52 (95% CI: 0.07, 0.97) kg/m(2)). Improvement in the neighborhood physical environment should be considered for its contribution to reducing obesity.

Associations of acculturation and socioeconomic status with subclinical cardiovascular disease in the multi-ethnic study of atherosclerosis

OBJECTIVES

We assessed whether markers of acculturation (birthplace and number of US generations) and socioeconomic status (SES) are associated with markers of subclinical cardiovascular disease-carotid artery plaque, internal carotid intima-media thickness, and albuminuria-in 4 racial/ethnic groups.

METHODS

With data from the Multi-Ethnic Study of Atherosclerosis (n = 6716 participants aged 45-84 years) and race-specific binomial regression models, we computed prevalence ratios adjusted for demographics and traditional cardiovascular risk factors.

RESULTS

The adjusted US- to foreign-born prevalence ratio for carotid plaque was 1.20 (99% confidence interval [CI] = 0.97, 1.39) among Whites, 1.91 (99% CI = 0.94, 2.94) among Chinese, 1.62 (99% CI = 1.28, 2.06) among Blacks, and 1.23 (99% CI = 1.15, 1.31) among Hispanics. Greater carotid plaque prevalence was found among Whites, Blacks, and Hispanics with a greater number of generations with US residence (P < .001) and among Whites with less education and among Blacks with lower incomes. Similar associations were observed with intima-media thickness. There was also evidence of an inverse association between albuminuria and SES among Whites and Hispanics.

CONCLUSIONS

Greater US acculturation and lower SES were associated with a higher prevalence of carotid plaque and greater intima-media thickness but not with albuminuria. Maintenance of healthful habits among recent immigrants should be encouraged.

Associations of the local food environment with diet quality--a comparison of assessments based on surveys and geographic information systems: the multi-ethnic study of atherosclerosis

There is growing interest in understanding how food environments affect diet, but characterizing the food environment is challenging. The authors investigated the relation between global diet measures (an empirically derived "fats and processed meats" (FPM) dietary pattern and the Alternate Healthy Eating Index (AHEI)) and three complementary measures of the local food environment: 1) supermarket density, 2) participant-reported assessments, and 3) aggregated survey responses of independent informants. Data were derived from the baseline examination (2000-2002) of the Multi-Ethnic Study of Atherosclerosis, a US study of adults aged 45-84 years. A healthy diet was defined as scoring in the top or bottom quintile of AHEI or FPM, respectively. The probability of having a healthy diet was modeled by each environment measure using binomial regression. Participants with no supermarkets near their homes were 25-46% less likely to have a healthy diet than those with the most stores, after adjustment for age, sex, race/ethnicity, and socioeconomic indicators: The relative probability of a healthy diet for the lowest store density category versus the highest was 0.75 (95% confidence interval: 0.59, 0.95) for the AHEI and 0.54 (95% confidence interval: 0.42, 0.70) for FPM. Similarly, participants living in areas with the worst-ranked food environments (by participants or informants) were 22-35% less likely to have a healthy diet than those in the best-ranked food environments. Efforts to improve diet may benefit from combining individual and environmental approaches.

Associations between recent exposure to ambient fine particulate matter and blood pressure in the Multi-ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Blood pressure (BP) may be implicated in associations observed between ambient particulate matter and cardiovascular morbidity and mortality. This study examined cross-sectional associations between short-term ambient fine particles (particulate matter <or= 2.5 microm in aerodynamic diameter; PM(2.5)) and BP: systolic (SBP), diastolic (DBP), mean arterial (MAP), and pulse pressure (PP).

METHODS

The study sample included 5,112 persons 45-84 years of age, free of cardiovascular disease at the Multi-Ethnic Study of Atherosclerosis baseline examination (2000-2002). Data from U.S. Environmental Protection Agency monitors were used to estimate ambient PM(2.5) exposures for the preceding 1, 2, 7, 30, and 60 days. Roadway data were used to estimate local exposures to traffic-related particles.

RESULTS

Results from linear regression found PP and SBP positively associated with PM(2.5). For example, a 10-microg/m(3) increase in PM(2.5) 30-day mean was associated with 1.12 mmHg higher pulse pressure [95% confidence interval (CI), 0.28-1.97] and 0.99 mmHg higher systolic BP (95% CI, -0.15 to 2.13), adjusted for age, sex, race/ethnicity, income, education, body mass index, diabetes, cigarette smoking and environmental tobacco smoke, alcohol use, physical activity, medications, atmospheric pressure, and temperature. Results were much weaker and not statistically significant for MAP and DBP. Although traffic-related variables were not themselves associated with BP, the association between PM(2.5) and BP was stronger in the presence of higher traffic exposure.

CONCLUSIONS

Higher SBP and PP were associated with ambient levels of PM(2.5) and the association was stronger in the presence of roadway traffic, suggesting that impairment of blood pressure regulation may play a role in response to air pollution.

Long-term exposure to ambient particulate matter and prevalence of subclinical atherosclerosis in the Multi-Ethnic Study of Atherosclerosis

Exposure to airborne particulate matter has been linked to cardiovascular events. Whether this finding reflects an effect of particulate matter exposure on the triggering of events or development of atherosclerosis remains unknown. Using data from the Multi-Ethnic Study of Atherosclerosis collected at baseline (2000-2002), the authors investigated associations of 20-year exposures to particulate matter with measures of subclinical disease (coronary calcium, common carotid intimal-medial thickness, and ankle-brachial index) in 5,172 US adults without clinical cardiovascular disease. Particulate matter exposures for the 20 years prior to assessment of subclinical disease were obtained from a space-time model of Environmental Protection Agency monitor data linked to residential history data for each participant. Intimal-medial thickness was weakly, positively associated with exposures to particulate matter <10 microm in aerodynamic diameter and <2.5 microm in aerodynamic diameter after controlling for age, sex, race/ethnicity, socioeconomic factors, diet, smoking, physical activity, blood lipids, diabetes, hypertension, and body mass index (1-4% increase per 21-microg/m(3) increase in particulate matter <10 microm in aerodynamic diameter or a 12.5-microg/m(3) increase in particulate matter <2.5 microm in aerodynamic diameter). No consistent associations with other measures of atherosclerosis were observed. There was no evidence of effect modification by sociodemographic factors, lipid status, smoking, diabetes, body mass index, or site. Results are compatible with some effect of particulate matter exposures on development of carotid atherosclerosis.

Comparing Perception-Based and Geographic Information System (GIS)-based characterizations of the local food environment

Measuring features of the local food environment has been a major challenge in studying the effect of the environment on diet. This study examined associations between alternate ways of characterizing the local food environment by comparing Geographic Information System (GIS)-derived densities of various types of stores to perception-based measures of the availability of healthy foods. Survey questions rating the availability of produce and low-fat products in neighborhoods were aggregated into a healthy food availability score for 5,774 residents of North Carolina, Maryland, and New York. Densities of supermarkets and smaller stores per square mile were computed for 1 mile around each respondent's residence using kernel estimation. The number of different store types in the area was used to measure variety in the food environment. Linear regression was used to examine associations of store densities and variety with reported availability. Respondents living in areas with lower densities of supermarkets rated the selection and availability of produce and low-fat foods 17% lower than those in areas with the highest densities of supermarkets (95% CL, -18.8, -15.1). In areas without supermarkets, low densities of smaller stores and less store variety were associated with worse perceived availability of healthy foods only in North Carolina (8.8% lower availability, 95% CL, -13.8, -3.4 for lowest vs. highest small-store density; 10.5% lower 95% CL, -16.0, -4.7 for least vs. most store variety). In contrast, higher smaller store densities and more variety were associated with worse perceived healthy food availability in Maryland. Perception- and GIS-based characterizations of the environment are associated but are not identical. Combinations of different types of measures may yield more valid measures of the environment.

Emergence of socioeconomic inequalities in smoking and overweight and obesity in early adulthood: the national longitudinal study of adolescent health

OBJECTIVES

We examined whether socioeconomic inequalities in smoking and overweight and obesity emerged in early adulthood and the contribution of family background, adolescent smoking, and body mass index to socioeconomic inequalities.

METHODS

Using data from the National Longitudinal Study of Adolescent Health we employed multinomial regression analyses to estimate relative odds of heavy or light-to-moderate smoking to nonsmoking and of overweight or obesity to normal weight.

RESULTS

For smoking, we found inequalities by young adult socioeconomic position in both genders after controlling for family background and smoking during adolescence. However, family socioeconomic position was not strongly associated with smoking in early adulthood. For overweight and obesity, we found socioeconomic inequalities only among women both by young adult and family socioeconomic position after adjusting for birthweight, other family background, and body mass index during adolescence.

CONCLUSIONS

Socioeconomic inequalities in smoking emerged in early adulthood according to socioeconomic position. Among women, inequalities in overweight or obesity were already evident by family socioeconomic position and strengthened by their own socioeconomic position. The relative importance of family background and current socioeconomic circumstances varied between smoking and overweight or obesity.

Availability of recreational resources in minority and low socioeconomic status areas

BACKGROUND

Differences in availability of recreational resources may contribute to racial and socioeconomic status (SES) disparities in physical activity. Variations in the location and density of recreational resources were examined by SES and racial composition of neighborhoods.

METHODS

Densities of resources available in recreational facilities and parks were estimated for census tracts between April 2003 and June 2004 in North Carolina, New York, and Maryland using kernel estimation. The probability of not having a facility or park was modeled by tract racial composition and SES, adjusting for population and area, using binomial regression in 2006. Mean densities of tract resources were modeled by SES and racial composition using linear regression.

RESULTS

Minority neighborhoods were significantly more likely than white neighborhoods not to have recreational facilities (relative probability [RP]=3.27 [95% CI=2.11-5.07] and 8.60 [95% CI=4.48-16.51], for black and Hispanic neighborhoods, respectively). Low-income neighborhoods were 4.5 times more likely to not have facilities than high-income areas (95% CI=2.87-7.12). Parks were more equitably distributed. Most resources located in recreational facilities required a fee and were less dense in minority and low-income areas. Those located inside parks were usually free to use, sports-related, and denser in poor and minority neighborhoods.

CONCLUSIONS

Recreational facilities and the resources they offer are not equitably distributed. The presence of parks in poor and minority areas suggest that improving the types and quality of resources in parks could be an important strategy to increase physical activity and reduce racial/ethnic and socioeconomic disparities.

Filling the gaps: spatial interpolation of residential survey data in the estimation of neighborhood characteristics

The measurement of area-level attributes remains a major challenge in studies of neighborhood health effects. Even when neighborhood survey data are collected, they necessarily have incomplete spatial coverage. We investigated whether interpolation of neighborhood survey data was aided by information on spatial dependencies and supplementary data. Neighborhood "availability of healthy foods" was measured in a population-based survey of 5186 persons in Baltimore, New York, and Forsyth County (North Carolina). The following supplementary data were compiled from Census 2000 and InfoUSA, Inc.: distance to supermarkets, density of supermarkets and fruit and vegetable stores, housing density, distance to a high-income area, and percent of households that do not own a vehicle. We compared 4 interpolation models (ordinary least squares, residual kriging, spatial error regression, and thin-plate splines) using error statistics and Pearson correlation coefficients (r) from repeated replications of cross-validations. There was positive spatial autocorrelation in neighborhood availability of healthy foods (by site, Moran coefficient range = 0.10-0.28; all P<0.0001). Prediction performances were generally similar for the evaluated models (r approximately 0.35 for Baltimore and Forsyth; r approximately 0.54 for New York). Supplementary data accounted for much of the spatial autocorrelation and, thus, spatial modeling was only advantageous when spatial correlation was at least moderate. A variety of interpolation techniques will likely need to be utilized in order to increase the data available for examining health effects of residential environments. The most appropriate method will vary depending on the construct of interest, availability of relevant supplementary data, and types of observed spatial patterns.

Area socioeconomic status and mortality after coronary artery bypass graft surgery: the role of hospital volume

BACKGROUND

Individuals of low socioeconomic status (SES) have reduced access to coronary artery bypass graft surgery (CABG). It is unknown if low-SES CABG patients have reduced access to hospitals with better outcomes.

METHODS

We conducted a retrospective cohort analysis of the California CABG Mortality Reporting Program, consisting of individuals with zip code information who underwent CABG at participating hospitals in 1999-2000 (n = 18,961). Primary outcome measures were inhospital mortality after CABG; primary independent variables of interest were area-level SES, clinical risk factors, and hospital volume. We used 2-level hierarchical random-effects logit models to estimate the relationship between explanatory variables and inhospital mortality.

RESULTS

Within high-volume hospitals, patients of low-SES areas had greater mortality than those of mid- and high-SES areas (2.5% vs 1.5% vs 1.8%, P = .024). However, there was no relationship between SES and mortality in lower-volume hospitals. Contrary to expectations, individuals of high-SES areas (42%) underwent surgery at low-volume hospitals more often than patients of low-SES areas (28%, P < .001), although mortality at low-volume hospitals was greater than that at high-volume facilities (P < .001). Discrepancies were not explained by distance traveled.

CONCLUSIONS

Mortality after CABG is modified by both SES and hospital volume. Within high-volume hospitals, patients of low-SES areas fared worse than patients of higher-SES areas. Patients of high SES tended to have CABG surgery at low-volume hospitals where mortality was greater and therefore had higher mortality than expected.

Individual and neighborhood socioeconomic status and progressive chronic kidney disease in an elderly population: The Cardiovascular Health Study

Few studies have focused on the association between socioeconomic status (SES) and progressive chronic kidney disease (pCKD) in an elderly population. We conducted a cohort study of 4735 Cardiovascular Health Study participants, ages 65 and older and living in 4 US communities, to examine the independent risk of pCKD associated with income, education and living in a low SES area. pCKD was defined as creatinine elevation 0.4 mg/dL (35 micromol/L) over a 4-7 year follow-up or CKD hospitalization. Area SES was characterized using measures of income, wealth, education and occupation for 1990 (corresponding to time of enrollment) US Census block groups of residence. Age and study site-adjusted incidence rates (per 1000 person years) of pCKD by quartiles of area-level SES score, income and education showed decreasing rates with increasing SES. Cox proportional hazards models showed that living in the lowest SES area quartile, as opposed to the highest, was associated with 50% greater risk of pCKD, after adjusting for age, gender, study site, baseline creatinine, and individual-level SES. This increased risk and trend persisted after adjusting for lifestyle risk factors, diabetes and hypertension. We found no significant independent associations between pCKD and individual-level income or education (after adjusting for all other SES factors). As such, living in a low SES area is associated with greater risk of pCKD in an elderly US population.

Integrating Social and Biologic Factors in Health Research: A Systems View

An important focus of recent calls for interdisciplinary approaches in health research has been the integration of social and biomedical sciences in understanding the causes of ill-health. Typical models for the incorporation of social factors into biomedical research include social factors as distal antecedents of more proximate biologic factors and gene-environment interaction. Under both models the distinction between social and biologic factors remains clear-cut, and consideration of social factors is not indispensable for understanding the biologic processes leading to disease. However, recent evidence suggests that social and biologic processes are inextricably linked in systems. This paper reviews models for the incorporation of social factors into the study of health, discusses the potentialities of systems approaches, and highlights implications for population health and epidemiology.

Socioeconomic position and incident mobility impairment in the Cardiovascular Health Study

BACKGROUND

We investigated if personal socioeconomic position (SEP) factors and neighborhood characteristics were associated with incident mobility impairment in the elderly.

METHODS

We used data from the Cardiovascular Health Study, a longitudinal, population-based examination of coronary heart disease and stroke among persons aged 65 and older in the United States.

RESULTS

Among 3,684 persons without baseline mobility impairment, lower baseline SEP was associated with increased risk of incident mobility disability during the 10-year follow-up period, although the strengths of these associations varied by socioeconomic indicator and race/sex group.

CONCLUSION

Among independent-living elderly, SEP affected development of mobility impairment into later life. Particular effort should be made to prevent or delay its onset among the elderly with low income, education, and/or who live in economically disadvantaged neighborhoods.

Intraurban variations in adult mortality in a large Latin American city

Urbanization is high and growing in low- and middle-income countries, but intraurban variations in adult health have been infrequently examined. We used spatial analysis methods to investigate spatial variation in total, cardiovascular disease, respiratory disease, and neoplasm adult mortality in Buenos Aires, Argentina, a large city within a middle-income country in Latin America. Conditional autoregressive models were used to examine the contribution of socioeconomic inequalities to the spatial patterning observed. Spatial autocorrelation was present in both men and women for total deaths, cardiovascular deaths, and other causes of death (Moran's Is ranging from 0.15 to 0.37). There was some spatial autocorrelation for respiratory deaths, which was stronger in men than in women. Neoplasm deaths were not spatially patterned. Socioeconomic disadvantage explained some of this spatial patterning and was strongly associated with death from all causes except respiratory deaths in women and neoplasms in men and women [relative rates (RR) for 90th vs 10th percentile of percent of adults with incomplete high school and 95% confidence intervals: 1.23 and 1.09-1.39 vs 1.24 and 1.08-1.42 for total deaths in men and women, respectively; 1.36 and 1.15-1.60 vs 1.22 and 1.01-1.47 for cardiovascular deaths; 1.21 and 0.97-1.52 vs 1.07 and 0.85-1.34 for respiratory deaths; 0.94 and 0.85-1.04 vs 1.03 and 0.87-1.22 for neoplasms; and 1.49 and 1.20-1.85 vs 1.63 and 1.31-2.03 for other deaths]. There is substantial intraurban variation in risk of death within cities. This spatial variability was present for multiple causes of death and is partly explained by the spatial patterning of socioeconomic disadvantage. Our results highlight the pervasive role of space and social inequalities in shaping life and death within large cities.

Assessing the measurement properties of neighborhood scales: from psychometrics to ecometrics

Most studies examining the relation between residential environment and health have used census-derived measures of neighborhood socioeconomic position (SEP). There is a need to identify specific features of neighborhoods relevant to disease risk, but few measures of these features exist, and their measurement properties are understudied. In this paper, the authors 1) develop measures (scales) of neighborhood environment that are important in cardiovascular disease risk, 2) assess the psychometric and ecometric properties of these measures, and 3) examine individual- and neighborhood-level predictors of these measures. In 2004, data on neighborhood conditions were collected from a telephone survey of 5,988 residents at three US study sites (Baltimore, Maryland; Forsyth County, North Carolina; and New York, New York). Information collected covered seven dimensions of neighborhood environment (aesthetic quality, walking environment, availability of healthy foods, safety, violence, social cohesion, and activities with neighbors). Neighborhoods were defined as census tracts or census clusters. Cronbach's alpha coefficient ranged from 0.73 to 0.83, with test-retest reliabilities of 0.60-0.88. Intraneighborhood correlations were 0.28-0.51, and neighborhood reliabilities were 0.64-0.78 for census tracts for most scales. The neighborhood scales were strongly associated with neighborhood SEP but also provided information distinct from neighborhood SEP. These results illustrate a methodological approach for assessing the measurement properties of neighborhood-level constructs and show that these constructs can be measured reliably.

Acculturation is associated with hypertension in a multiethnic sample

BACKGROUND

Hypertension varies in prevalence among race/ethnic groups in the United States. Within-ethnic group differences associated with acculturation have been less frequently examined. We studied the association of three measures of acculturation (language spoken at home, place of birth, and years living in the US) with hypertension in a population sample of 2619 white, 1898 African American, 1,494 Hispanic, and 803 Chinese participants in the Multiethnic Study of Atherosclerosis.

METHODS

Multivariate Poisson regression was used to estimate the association between the acculturation variables and hypertension.

RESULTS

Birthplace outside the US and speaking a non-English language at home were each associated with a lower prevalence of hypertension after adjustment for age, gender, and socioeconomic status (prevalence ratio [95% confidence intervals] 0.82 (0.77-0.87) for non-US born versus US born and 0.80 (0.74-0.85) for those not speaking English at home versus speakers of English at home, both P < .001). For participants born outside of the US, each 10-year increment of years in the US was associated with a higher prevalence of hypertension after adjustment for age, gender, and socioeconomic status (P for trend < .01). The associations between acculturation variables and hypertension were weakened after adjustment for race/ethnic category and risk factors for hypertension. Compared to US-born Hispanics, those born in Mexico or South America had lower prevalence of hypertension, but those born in the Caribbean and Central America had higher prevalence of hypertension.

CONCLUSIONS

Acculturation and place of birth are associated with hypertension in a multiethnic sample.

Kidney disease in life-course socioeconomic context: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Persons belonging to the working class or living in an adverse social environment at particular periods of their life course may have an increased risk of chronic kidney disease (CKD).

METHODS

This hypothesis was examined among participants of the Life Course Socioeconomic Status Study, an ancillary study of the Atherosclerosis Risk in Communities Study, conducted in 2001 (mean age, 67.4 years; N = 12,631). CKD was defined by hospital discharge diagnosis and/or estimated glomerular filtration rate less than 45 mL/min/1.73 m(2) (<0.75 mL/s/1.73 m(2)). Social class was categorized as working class or non-working class at ages 30, 40, or 50 years. Area-level socioeconomic status was based on a composite of census scores during the same period. Adjusted odds ratios were obtained within strata of white and African-American race.

RESULTS

The adjusted odds ratio of CKD for persons belonging to the working class versus non-working class at age 30 was 1.4 (95% confidence interval, 1.0 to 2.0) in whites and 1.9 (95% confidence interval, 1.1 to 3.0) in African Americans. Working class membership was associated with CKD, even at earlier stages of adult life, and class was associated more strongly with CKD than was education. Working class membership also suggested a stronger association with CKD among African Americans than whites, independent of diabetes and hypertension status. At later periods in the life course, area socioeconomic status was associated with CKD.

CONCLUSION

Socioeconomic factors, including area socioeconomic status and social class, are associated with CKD and may account for some of the racial disparity in kidney disease.

Association of insulin resistance with distance to wealthy areas: the multi-ethnic study of atherosclerosis

Little is known about environmental determinants of type 2 diabetes. The authors hypothesized that insulin resistance is positively related to distance to a wealthy area and to local neighborhood poverty. Data were derived from The Multi-Ethnic Study of Atherosclerosis, a study of adults aged 45-84 years in six US locales, and the 2000 US Census. The homeostasis model assessment (HOMA) index was used to measure insulin resistance. Linear regression was used to estimate associations between area characteristics and insulin resistance after adjustment for age, sex, income, education, and race/ethnicity and for the potential mediators diet, physical activity, and body mass index (n = 4,821). Among persons not treated for diabetes, distance to a wealthy area was associated with HOMA independent of local poverty and person-level covariates: per 4.4-km change, the relative increase in HOMA was 13% (95% confidence interval: 7%, 19%), similar to the effect of a body mass index increase of 1.7 kg/m(2) on HOMA. This association was reduced after adjustment for physical activity, diet, and body mass index (relative increase = 9%, 95% confidence interval: 3%, 15%). Local neighborhood poverty was also positively, but more weakly associated with insulin resistance, with no association after adjustment for race/ethnicity. This study shows that proximity to resources in high-income areas is related to insulin resistance.

Availability of recreational resources and physical activity in adults

OBJECTIVES

Using data from a large cohort of adults aged 45 to 84 years-old, we investigated whether availability of recreational resources is related to physical activity levels.

METHODS

Data from a multiethnic sample of 2723 adult residents of New York City, NY; Baltimore, Md; and Forsyth County, NC, were linked to data on locations of recreational resources. We measured the availability (density) of resources within 0.5 (0.8 km), 1, 2, and 5 miles of each participant's residence and used binomial regression to investigate associations of density with physical activity.

RESULTS

After adjustment for potential confounders, individuals in the tertile of participants residing in areas with the highest density of resources were more likely to report physical activity during a typical week than were individuals in the lowest tertile. Associations between availability of recreational resources and physical activity levels were not present for the smallest area assessed (0.5 miles) but were present for areas ranging from 1 to 5 miles. These associations were slightly stronger among minority and low-income residents.

CONCLUSIONS

Availability of resources may be 1 of several environmental factors that influence individuals' physical activity behaviors.

Psychosocial factors and coronary calcium in adults without clinical cardiovascular disease

BACKGROUND

Psychosocial factors have been linked to coronary events, but the mechanisms underlying these associations have not been established. Evidence is mixed regarding associations of psychosocial factors with subclinical coronary atherosclerosis.

OBJECTIVE

To examine associations of 4 psychosocial factors (depressive symptoms, anger, anxiety, and chronic stress) with the presence of subclinical coronary atherosclerosis.

DESIGN

Cross-sectional study.

SETTING

The Multiethnic Study of Atherosclerosis, a population-based study of subclinical atherosclerosis.

PATIENTS

A multiethnic sample of 6789 adults, 45 to 84 years of age, with no history of clinical cardiovascular disease.

MEASUREMENTS

Coronary calcium was assessed by using chest computed tomography, and psychosocial factors were assessed by using questionnaires with validated scales.

RESULTS

There was no evidence that higher levels of the psychosocial measures were associated with greater prevalence of calcification or with greater amounts of calcium among persons with calcium. Age- and risk factor-adjusted relative prevalences of coronary calcification in men for the top fourth category versus the bottom fourth category of anger, anxiety, and depressive symptoms were 0.94 (95% CI, 0.88 to 1.01), 0.97 (CI, 0.90 to 1.04), and 0.97 (CI, 0.90 to 1.05), respectively; these values for women were 1.01 (CI, 0.90 to 1.15), 0.93 (CI, 0.83 to 1.05), and 0.92 (CI, 0.82 to 1.04), respectively. Relative prevalences for the top versus the bottom category of chronic stress burden were 1.02 (CI, 0.94 to 1.11) for men and 0.88 (CI, 0.79 to 0.99) for women.

LIMITATIONS

Current measures of psychosocial factors may be a poor proxy for cumulative exposure during development of atherosclerosis.

CONCLUSION

Depressive symptoms, anger, anxiety, and chronic stress burden were not associated with coronary calcification in a multiethnic sample of asymptomatic adults.

Supermarkets, other food stores, and obesity: the atherosclerosis risk in communities study

BACKGROUND

Obesity is a leading public health concern, and although environmental factors have been hypothesized to play a role in the prevention of obesity, little empirical data exist to document their effects. The purpose of this study was to examine whether characteristics of the local food environment are associated with the prevalence of cardiovascular disease risk factors.

METHODS

A cross-sectional study of men and women participating in the third visit (1993-1995) of the Atherosclerosis Risk in Communities (ARIC) Study was conducted in 2004. The analyses included 10,763 ARIC participants residing in one of the 207 eligible census tracts located in the four ARIC-defined geographic areas. Names and addresses of food stores located in Mississippi, North Carolina, Maryland, and Minnesota were obtained from departments of agriculture. Multilevel modeling was used to calculate prevalence ratios of the associations between the presence of specific types of food stores and cardiovascular disease risk factors.

RESULTS

The presence of supermarkets was associated with a lower prevalence of obesity and overweight (obesity prevalence ratio [PR] = 0.83, 95% confidence interval [CI] = 0.75-0.92; overweight PR = 0.94, 95% CI = 0.90-0.98), and the presence of convenience stores was associated with a higher prevalence of obesity and overweight (obesity PR = 1.16, 95% CI = 1.05-1.27; overweight PR = 1.06, 95% CI = 1.02-1.10). Associations for diabetes, high serum cholesterol, and hypertension were not consistently observed.

CONCLUSIONS

Results from this study suggest that characteristics of local food environments may play a role in the prevention of overweight and obesity.