Marilyn A. Winkleby

Socioeconomic status and health: how education, income, and occupation contribute to risk factors for cardiovascular disease.

BACKGROUND Socioeconomic status (SES) is usually measured by determining education, income, occupation, or a composite of these dimensions. Although education is the most commonly used measure of SES in epidemiological studies, no investigators in the United States have conducted an empirical analysis quantifying the relative impact of each separate dimension of SES on risk factors for disease. METHODS Using data on 2380 participants from the Stanford Five-City Project (85% White, non-Hispanic), we examined the independent contribution of education, income, and occupation to a set of cardiovascular disease risk factors (cigarette smoking, systolic and diastolic blood pressure, and total and high-density lipoprotein cholesterol). RESULTS The relationship between these SES measures and risk factors was strongest and most consistent for education, showing higher risk associated with lower levels of education. Using a forward selection model that allowed for inclusion of all three SES measures after adjustment for age and time of survey, education was the only measure that was significantly associated with the risk factors (P less than .05). CONCLUSION If economics or time dictate that a single parameter of SES be chosen and if the research hypothesis does not dictate otherwise, higher education may be the best SES predictor of good health.

Socioeconomic and food-related physical characteristics of the neighbourhood environment are associated with body mass index

Objective: To determine whether socioeconomic and food-related physical characteristics of the neighbourhood are associated with body mass index (BMI; kg/m2) independently of individual-level sociodemographic and behavioural characteristics. Design and methods: Observational study using (1) individual-level data previously gathered in five cross-sectional surveys conducted by the Stanford Heart Disease Prevention Program between 1979 and 1990 and (2) neighbourhood-level data from (a) the census to describe socioeconomic characteristics and (b) data obtained from government and commercial sources to describe exposure to different types of retail food stores as measured by store proximity, and count of stores per square mile. Data were analysed using multilevel modelling procedures. The setting was 82 neighbourhoods in agricultural regions of California. Participants: 7595 adults, aged 25–74 years. Results: After adjusting for age, gender, ethnicity, individual-level socioeconomic status, smoking, physical activity and nutrition knowledge, it was found that (1) adults who lived in low socioeconomic neighbourhoods had a higher mean BMI than adults who lived in high socioeconomic neighbourhoods; (2) higher neighbourhood density of small grocery stores was associated with higher BMI among women; and (3) closer proximity to chain supermarkets was associated with higher BMI among women. Conclusion: Living in low socioeconomic neighbourhoods, and in environments where healthy food is not readily available, is found to be associated with increased obesity risk. Unlike other studies which examined populations in other parts of the US, a positive association between living close to supermarkets and reduced obesity risk was not found in this study. A better understanding of the mechanisms by which neighbourhood physical characteristics influence obesity risk is needed.

Social class disparities in risk factors for disease: eight-year prevalence patterns by level of education.

This article examines the associations between education, a primary indicator of social class, and six risk factors for disease. Data are presented on a sample of 3,349 individuals ages 25-74 years who participated in one of four cross-sectional surveys conducted by the Stanford Five-City Project between 1979 and 1986. The six risk factors examined are knowledge about health, cigarette smoking, hypertension, serum cholesterol, body mass index, and height. A highly significant pattern of associations was found between education level and the six risk factors, in the direction of higher risk among those with lower education (all P values less than 0.01). These associations persisted for both sexes and in the younger as well as the older age groups, with the exception of cholesterol values for males and for those in the 50 to 74-year-old age group. Furthermore, all associations remained highly significant after controlling for income and occupation, two other indicators of social class. When a summary-adjusted risk score was plotted against year of survey for the five education levels, a gradient of effect was observed where each progressive education level showed a decrease in total risk score. This gradient was replicated in all four cross-sectional surveys, providing evidence for the consistency of the findings over time.

Comorbidities and Mortality in Persons With Schizophrenia: A Swedish National Cohort Study

OBJECTIVE Schizophrenia is associated with premature mortality, but the specific causes and pathways are unclear. The authors used outpatient and inpatient data for a national population to examine the association between schizophrenia and mortality and comorbidities. METHOD This was a national cohort study of 6,097,834 Swedish adults, including 8,277 with schizophrenia, followed for 7 years (2003-2009) for mortality and comorbidities diagnosed in any outpatient or inpatient setting nationwide. RESULTS On average, men with schizophrenia died 15 years earlier, and women 12 years earlier, than the rest of the population, and this was not accounted for by unnatural deaths. The leading causes were ischemic heart disease and cancer. Despite having twice as many health care system contacts, schizophrenia patients had no increased risk of nonfatal ischemic heart disease or cancer diagnoses, but they had an elevated mortality from ischemic heart disease (adjusted hazard ratio for women, 3.33 [95% CI=2.73-4.05]; for men, 2.20 [95% CI=1.83-2.65]) and cancer (adjusted hazard ratio for women, 1.71 [95% CI=1.38-2.10; for men, 1.44 [95% CI=1.15-1.80]). Among all people who died from ischemic heart disease or cancer, schizophrenia patients were less likely than others to have been diagnosed previously with these conditions (for ischemic heart disease, 26.3% compared with 43.7%; for cancer, 73.9% compared with 82.3%). The association between schizophrenia and mortality was stronger among women and the employed. Lack of antipsychotic treatment was also associated with elevated mortality. CONCLUSIONS Schizophrenia patients had markedly premature mortality, and the leading causes were ischemic heart disease and cancer, which appeared to be underdiagnosed. Preventive interventions should prioritize primary health care tailored to this population, including more effective risk modification and screening for cardiovascular disease and cancer.

Cardiovascular disease risk factors among older black, Mexican-American, and white women and men: an analysis of NHANES III, 1988-1994. Third National Health and Nutrition Examination Survey.

CONTEXT: There are few studies of ethnic differences in cardiovascular disease (CVD) risk factors in older populations.

Cardiovascular risk factors in Mexican American adults: a transcultural analysis of NHANES III, 1988-1994.

OBJECTIVES This study examined the extent to which cardiovascular disease risk factors differ among subgroups of Mexican Americans living in the United States. METHODS Using data from a national sample (1988-1994) of 1387 Mexican American women and 1404 Mexican American men, aged 25 to 64 years, we examined an estimate of coronary heart disease mortality risk and 5 primary cardiovascular disease risk factors: systolic blood pressure, body mass index, cigarette smoking, non-high-density lipoprotein cholesterol, and type 2 diabetes mellitus. Differences in risk were evaluated by country of birth and primary language spoken. RESULTS Estimated 10-year coronary heart disease mortality risk per 1000 persons, adjusted for age and education, was highest for US-born Spanish-speaking men and women (27.5 and 11.4, respectively), intermediate for US-born English-speaking men and women (22.5 and 7.0), and lowest for Mexican-born men and women (20.0 and 6.6). A similar pattern of higher risk among US-born Spanish-speaking men and women was demonstrated for each of the 5 cardiovascular disease risk factors. CONCLUSIONS These findings illustrate the heterogeneity of the Mexican American population and identify a new group at substantial risk for cardiovascular disease and in need of effective heart disease prevention programs.

Comorbidities and Mortality in Bipolar Disorder: A Swedish National Cohort Study

IMPORTANCE Bipolar disorder is associated with premature mortality, but the specific causes and underlying pathways are unclear. OBJECTIVE To examine the physical health effects of bipolar disorder using outpatient and inpatient data for a national population. DESIGN, SETTING, AND PARTICIPANTS National cohort study of 6,587,036 Swedish adults, including 6618 with bipolar disorder. MAIN OUTCOMES AND MEASURES Physical comorbidities diagnosed in any outpatient or inpatient setting nationwide and mortality (January 1, 2003, through December 31, 2009). RESULTS Women and men with bipolar disorder died 9.0 and 8.5 years earlier on average than the rest of the population, respectively. All-cause mortality was increased 2-fold among women (adjusted hazard ratio [aHR], 2.34; 95% CI, 2.16-2.53) and men (aHR, 2.03; 95% CI, 1.85-2.23) with bipolar disorder, compared with the rest of the population. Patients with bipolar disorder had increased mortality from cardiovascular disease, diabetes mellitus, chronic obstructive pulmonary disease (COPD), influenza or pneumonia, unintentional injuries, and suicide for both women and men and cancer for women only. Suicide risk was 10-fold among women (aHR, 10.37; 95% CI, 7.36-14.60) and 8-fold among men (aHR, 8.09; 95% CI, 5.98-10.95) with bipolar disorder, compared with the rest of the population. Substance use disorders contributed only modestly to these findings. The association between bipolar disorder and mortality from chronic diseases (ischemic heart disease, diabetes, COPD, or cancer) was weaker among persons with a prior diagnosis of these conditions (aHR, 1.40; 95% CI, 1.26-1.56) than among those without a prior diagnosis (aHR, 2.38; 95% CI, 1.95-2.90; P(interaction) = .01). CONCLUSIONS AND RELEVANCE In this large national cohort study, patients with bipolar disorder died prematurely from multiple causes, including cardiovascular disease, diabetes, COPD, influenza or pneumonia, unintentional injuries, and suicide. However, chronic disease mortality among those with more timely medical diagnosis approached that of the general population, suggesting that better provision of primary medical care may effectively reduce premature mortality among persons with bipolar disorder.

Influence of individual and neighbourhood socioeconomic status on mortality among black, Mexican-American, and white women and men in the United States

Study objectives: This study examines the influence of individual and neighbourhood socioeconomic status (SES) on mortality among black, Mexican-American, and white women and men in the US. The authors had three study objectives. Firstly, they examined mortality rates by both individual level SES (measured by income, education, and occupational/employment status) and neighbourhood level SES (index of neighbourhood income/wealth, educational attainment, occupational status, and employment status). Secondly, they examined whether neighbourhood SES was associated with mortality after controlling for individual SES. Thirdly, they calculated the population attributable risk to estimate the reduction in mortality rates if all women and men lived in the highest SES neighbourhoods. Design: National Health Interview Survey (1987–1994), linked with 1990 census tract (neighbourhood proxy) and mortality data through 1997. Setting/participants: Nationally representative sample of 59 935 black, 19 201 Mexican-American, and 344 432 white men and women (six gender and racial/ethnic groups), aged 25–64 at interview. Main results: Mortality rates for all six gender and racial/ethnic groups were two to four times higher for those with the lowest incomes (lowest quartile) who lived in the lowest SES neighbourhoods (lowest tertile) compared with those with the highest incomes who lived in the highest SES neighbourhoods. For the six groups, the age adjusted mortality risk associated with living in the lowest SES neighbourhoods ranged from 1.43 to 1.61. The mortality risk decreased but remained significant (p values <.05) after adjusting for each of the three individual measures of SES, with the exception of Mexican-American women. Furthermore, the mortality risk associated with living in the lowest SES neighbourhoods remained significant after simultaneously adjusting for all three individual measures of SES for white men (p<0.001) and white women (p<0.05). Deaths would hypothetically be reduced by about 20% for each subgroup if everyone had the same death rates as those living in the highest SES neighbourhoods (highest tertile). Conclusions: Living in a low SES neighbourhood confers additional mortality risk beyond individual SES.

Gestational Age at Birth and Mortality in Young Adulthood

CONTEXT Preterm birth is the leading cause of infant mortality in developed countries, but the association between gestational age at birth and mortality in adulthood remains unknown. OBJECTIVE To examine the association between gestational age at birth and mortality in young adulthood. DESIGN, SETTING, AND PARTICIPANTS National cohort study of 674,820 individuals born as singletons in Sweden in 1973 through 1979 who survived to age 1 year, including 27,979 born preterm (gestational age <37 weeks), followed up to 2008 (ages 29-36 years). MAIN OUTCOME MEASURES All-cause and cause-specific mortality. RESULTS A total of 7095 deaths occurred in 20.8 million person-years of follow-up. Among individuals still alive at the beginning of each age range, a strong inverse association was found between gestational age at birth and mortality in early childhood (ages 1-5 years: adjusted hazard ratio [aHR] for each additional week of gestation, 0.92; 95% CI, 0.89-0.94; P < .001), which disappeared in late childhood (ages 6-12 years: aHR, 0.99; 95% CI, 0.95-1.03; P = .61) and adolescence (ages 13-17 years: aHR, 0.99; 95% CI, 0.95-1.03; P = .64) and then reappeared in young adulthood (ages 18-36 years: aHR, 0.96; 95% CI, 0.94-0.97; P < .001). In young adulthood, mortality rates (per 1000 person-years) by gestational age at birth were 0.94 for 22 to 27 weeks, 0.86 for 28 to 33 weeks, 0.65 for 34 to 36 weeks, 0.46 for 37 to 42 weeks (full-term), and 0.54 for 43 or more weeks. Preterm birth was associated with increased mortality in young adulthood even among individuals born late preterm (34-36 weeks, aHR, 1.31; 95% CI, 1.13-1.50; P < .001), relative to those born full-term. In young adulthood, gestational age at birth had the strongest inverse association with mortality from congenital anomalies and respiratory, endocrine, and cardiovascular disorders and was not associated with mortality from neurological disorders, cancer, or injury. CONCLUSION After excluding earlier deaths, low gestational age at birth was independently associated with increased mortality in early childhood and young adulthood.

Neighborhood deprivation and cardiovascular disease risk factors: Protective and harmful effects

Aims: To determine whether neighborhood-level deprivation is independently associated with cardiovascular disease (CVD) health behaviors/risk factors in the Swedish population. Methods: Pooled cross-sectional data, Swedish Annual Level of Living Survey (1996—2000) linked with indicators of neighborhood-level (i.e. Small Area Market Statistics areas) deprivation (1997), to examine the association between neighborhood-level deprivation and individual-level smoking, physical inactivity, obesity, diabetes, and hypertension among women and men, aged 25—64 (n=18,081). Data were analyzed with a series of logistic regression models that adjusted for individual-level age, gender, marital status, immigration status, urbanization, and a comprehensive measure of socioeconomic status (SES). Interactions were tested to determine whether neighborhood effects varied by SES or length of neighborhood exposure. Results: Living in a neighborhood with low deprivation was protective (i.e. lower odds) for smoking, while living in a neighborhood with high deprivation was harmful (i.e. higher odds) for smoking, physical inactivity, and obesity (compared with living in a neighborhood with moderate deprivation). These associations were significant after adjustment for individual-level characteristics. There was no evidence that the neighborhood deprivation associations varied by individual-level SES or length of neighborhood exposure. Conclusions: Neighborhood-level deprivation exerted important protective and harmful associations with health behaviors/ risk factors related to CVD. The significance to public health is substantial because of the number of persons at risk as well as the serious health consequences of CVD. These results suggest that interventions focusing on changing contextual aspects of neighborhoods, in addition to changing individual behaviors, may have a greater impact on CVD than a sole focus on individuals.