Life-course perspective on socioeconomic differences in carotid atherosclerosis

Life Course Socioeconomic Position and Subclinical Disease: The Jackson Heart Study

OBJECTIVES

African Americans experience higher rates of cardiovascular disease (CVD) and lower childhood and adult socioeconomic position (SEP). Research that examines the associations of multiple measures of SEP with subclinical CVD markers among African Americans is limited.

METHODS

Data from the Jackson Heart Study (JHS) were used to examine cross-sectional associations of childhood SEP and adult SEP with subclinical markers among 4,756 African American participants (mean age 54, 64% female), adjusting for age, health behaviors and CVD risk factors. Subclinical markers included prevalent left ventricular hypertrophy (LVH), peripheral artery disease (PAD), coronary artery calcification (CAC), and carotid intima-media thickness (CIMT).

RESULTS

The prevalence of LVH, PAD and CAC was 7%, 6% and 45%, respectively. The mean CIMT was .72 ± .17 mm. In fully-adjusted models, having a college education was inversely associated with PAD (OR, .27; 95% CI .13,.56) and CIMT (β=-29.7, P<.01). Income was inversely associated with LVH after adjustment for health behaviors (OR, .49 95% CI .25,.96), though associations attenuated in the fully-adjusted model. Measures of childhood SEP (material resources and mother's education) were not consistently associated with subclinical disease measures other than a positive association between material resources and CIMT.

CONCLUSIONS

Subclinical disease markers were patterned by adult SEP measures among African Americans.

Socioeconomic Conditions in Childhood, Adolescence, and Adulthood and the Risk of Ischemic Stroke

BACKGROUND AND PURPOSE

The association between socioeconomic status in adulthood and the risk of stroke is well established; however, the independent effects of socioeconomic conditions in different life phases are less understood.

METHODS

Within a population-based stroke registry, we performed a case-control study with 470 ischemic stroke patients (cases) aged 18 to 80 years and 809 age- and sex-matched stroke-free controls, randomly selected from the population (study period October 2007 to April 2012). We assessed socioeconomic conditions in childhood, adolescence, and adulthood, and developed a socioeconomic risk score for each life period.

RESULTS

Socioeconomic conditions were less favorable in cases regarding paternal profession, living conditions and estimated family income in childhood, school degree, and vocational training in adolescence, last profession, marital status and periods of unemployment in adulthood. Using tertiles of score values, low socioeconomic conditions during childhood (odds ratio 1.77; 95% confidence interval 1.20-2.60) and adulthood (odds ratio 1.74; 95% confidence interval 1.16-2.60) but not significantly during adolescence (odds ratio 1.64; 95% confidence interval 0.97-2.78) were associated with stroke risk after adjustment for risk factors and other life stages. Medical risk factors attenuated the effect of childhood conditions, and lifestyle factors reduced the effect of socioeconomic conditions in adolescence and adulthood. Unfavorable childhood socioeconomic conditions were particularly associated with large artery atherosclerotic stroke in adulthood (odds ratio 2.13; 95% confidence interval 1.24-3.67).

CONCLUSIONS

This study supports the hypothesis that unfavorable childhood socioeconomic conditions are related to ischemic stroke risk, independent of established risk factors and socioeconomic status in adulthood, and fosters the idea that stroke prevention needs to begin early in life.

Associations of life course socioeconomic position and job stress with carotid intima-media thickness. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

RATIONALE

The association between life course socioeconomic position (SEP) and subclinical atherosclerosis is not consistent across studies. Socioeconomic adversities early in life are related to an increased probability of a low occupational grade and more stressful jobs in adulthood. However, the role of job stress in explaining the life course social gradient in subclinical atherosclerosis is unknown.

OBJECTIVES

To examine whether life course SEP is associated with carotid intima-media thickness (IMT) and to investigate whether this association is partially mediated by job stress.

METHODS

This study used baseline data (2008-2010) for 8806 current workers from ELSA-Brasil. Maternal education, social class of first occupation and social class of current occupation were used to evaluate childhood, youth and adulthood SEP, respectively. Accumulation of risk across the life course was also evaluated. Job stress was assessed by the Swedish Demand-Control-Support Questionnaire. Directed acyclic graph and linear regression models were used.

RESULTS

Low childhood SEP was associated with increased IMT only in women, but low youth and adulthood SEP were associated with higher IMT in both genders. The simultaneous adjustment for all SEP indicators showed that only adulthood SEP continued to be associated with IMT. However, higher IMT values were observed among men and women sequentially exposed to low SEP in more than one period of life. High-strain jobs and low job control were not associated with IMT independent of SEP.

CONCLUSION

Our results support a model of the cumulative effects of exposures to SEP across the life span because the highest IMT values were observed in individuals sequentially exposed to low SEP in more than one period of life. We did not find that job stress explained the association between life course SEP and IMT, suggesting that strategies to address socioeconomic inequalities in CVD should target additional steps beyond reducing job stress.

Prediction of asymptomatic carotid artery stenosis in the general population: identification of high-risk groups

BACKGROUND AND PURPOSE

Because of a low prevalence of severe carotid stenosis in the general population, screening for presence of asymptomatic carotid artery stenosis (ACAS) is not warranted. Possibly, for certain subgroups, screening is worthwhile. The present study aims to develop prediction rules for the presence of ACAS (>50% and >70%).

METHODS

Individual participant data from 4 population-based cohort studies (Malmö Diet and Cancer Study, Tromsø Study, Carotid Atherosclerosis Progression Study, and Cardiovascular Health Study; totaling 23 706 participants) were pooled. Multivariable logistic regression was performed to determine which variables predict presence of ACAS (>50% and >70%). Calibration and discrimination of the models were assessed, and bootstrapping was used to correct for overfitting.

RESULTS

Age, sex, history of vascular disease, systolic and diastolic blood pressure, total cholesterol/high-density lipoprotein ratio, diabetes mellitus, and current smoking were predictors of stenosis (>50% and >70%). The calibration of the model was good confirmed by a nonsignificant Hosmer and Lemeshow test for moderate (P=0.59) and severe stenosis (P=0.07). The models discriminated well between participants with and without stenosis, with an area under the receiver operating characteristic curve corrected for over optimism of 0.82 (95% confidence interval, 0.80-0.84) for moderate stenosis and of 0.87 (95% confidence interval, 0.85-0.90) for severe stenosis. The regression coefficients of the predictors were converted into a score chart to facilitate practical application.

CONCLUSIONS

A clinical prediction rule was developed that allows identification of subgroups with high prevalence of moderate (>50%) and severe (>70%) ACAS. When confirmed in comparable cohorts, application of the prediction rule may lead to a reduction in the number needed to screen for ACAS.

Low socioeconomic status over 12 years and subclinical cardiovascular disease: the study of women's health across the nation

BACKGROUND AND PURPOSE

The inverse relation between socioeconomic status and cardiovascular disease is well established. However, few studies have investigated socioeconomic status assessed repeatedly during adulthood in relation to subclinical atherosclerosis. We aimed to test whether consistently low socioeconomic status, as indexed by education, income, and financial strain, for 12 years of midlife was related to later carotid intima-media thickness and plaque among women.

METHODS

The Study of Women's Health Across the Nation is a multisite longitudinal study of midlife women. Education was assessed at the study baseline, income and financial strain were obtained yearly for 12 years, and a carotid ultrasound was obtained at study year 12 among 1402 women. Associations were tested in linear and multinomial logistic regression models adjusted for demographic, biological, and behavioral risk factors.

RESULTS

A high school education or less (odds ratio [OR] [95% confidence interval {CI}], 1.72 [1.15-2.59]; P<0.01), some college education (OR [95% CI], 1.65 [1.17-2.32]; P<0.01), consistently low income (OR [95% CI], 1.83 [1.15-2.89]; P<0.05), and consistent financial strain (OR [95% CI], 1.78 [1.21-2.61]; P<0.01) for 12 years were associated with higher carotid plaque, and consistent financial strain was associated with elevated maximal intima-media thickness (β [SE]=0.02 [0.01]; P<0.05) controlling for standard cardiovascular disease risk factors. When socioeconomic status indices were considered together, financial strain (β [SE]=0.02 [0.01]; P<0.05) and low education (high school education or less: OR [95% CI], 1.55 [1.01-2.37]; P<0.05; some college: OR [95% CI], 1.56 [1.09-2.21]; P<0.05) were most consistently associated with intima-media thickness and plaque, respectively, controlling for risk factors.

CONCLUSIONS

The findings indicate the importance of targeting economically disadvantaged women in efforts to prevent cardiovascular disease among women.

Women and cardiovascular disease: at a social disadvantage?

BACKGROUND

Cardiovascular disease is the most common cause of death in Australian women. The genesis and progression of cardiovascular disease is modulated by a complex interplay of genetic, physiological, social and economic circumstances. Increasingly the impact of racial, ethic, social and economic inequalities is identified as predictors of cardiovascular disease outcome. Despite important advances over the last 30 years in reducing age adjusted mortality from cardiovascular disease, it continues to represent a major social and economic burden nationally and internationally.

AIM

This paper provides a critical review of the social issues impacting upon women in Australia. It also identifies areas for future interventions with a view to improving outcomes in women with cardiovascular disease.

METHOD

The bibliographic databases; CINAHL, MEDLINE, PsycARTICLES, were searched for relevant studies using the search terms 'women', 'cardiovascular disease', and 'socio-economic status'.

FINDINGS

While some gains have been made in reducing the risk factor profile and rates of death from cardiovascular disease, it is clear that gender, race and socioeconomic disparities persist.

CONCLUSIONS

New approaches are required to improve health differentials for CVD, and reduce the impact of gender, racial, ethic, social and economic factors on health disparities.

Socioeconomic status and subclinical atherosclerosis in older adults

OBJECTIVE

This study investigated the long-term effects of socioeconomic status (SES) on atherosclerosis.

METHODS

Data from the Epidemiology of Hearing Loss Study and the Beaver Dam Eye Study (Beaver Dam, WI, 1998-2000), were used to examine adult SES (education, household income, and longest-held job) and childhood SES (household density and parental home ownership at age 13) associations with carotid intima-media thickness (IMT) and carotid plaque in a cohort of 2042 men and women aged 53 to 94 years.

RESULTS

For education, income, and occupation (women), those in the lowest SES group had statistically larger age-sex-adjusted IMT than those in the highest SES group (<12 vs. >12 years education: 0.92 vs. 0.86 mm respectively, P<0.0001), (<$10,000 vs. >$45,000: 0.97 vs. 0.87 mm, P<0.0001), (operator/fabricator/labor vs. manager/professional: 0.89 vs. 0.82 mm, P<0.001). Associations were similar using carotid plaque as the outcome. Participants with low levels of both adult and childhood SES measures had age-sex-adjusted IMT greater than those with persistently high levels of SES (0.93 vs. 0.84 mm, P<0.0001).

CONCLUSIONS

Measures of SES at two points in the life-span were associated with subclinical atherosclerosis.

Prevalence of asymptomatic carotid artery stenosis in the general population: an individual participant data meta-analysis

BACKGROUND AND PURPOSE

In the discussion on the cost-effectiveness of screening, precise estimates of severe asymptomatic carotid stenosis are vital. Accordingly, we assessed the prevalence of moderate and severe asymptomatic carotid stenosis by age and sex using pooled cohort data.

METHODS

We performed an individual participant data meta-analysis (23 706 participants) of 4 population-based studies (Malmö Diet and Cancer Study, Tromsø, Carotid Atherosclerosis Progression Study, and Cardiovascular Health Study). Outcomes of interest were asymptomatic moderate (> or =50%) and severe carotid stenosis (> or =70%).

RESULTS

Prevalence of moderate asymptomatic carotid stenosis ranged from 0.2% (95% CI, 0.0% to 0.4%) in men aged <50 years to 7.5% (5.2% to 10.5%) in men aged > or =80 years. For women, this prevalence increased from 0% (0% to 0.2%) to 5.0% (3.1% to 7.5%). Prevalence of severe asymptomatic carotid stenosis ranged from 0.1% (0.0% to 0.3%) in men aged <50 years to 3.1% (1.7% to 5.3%) in men aged > or =80. For women, this prevalence increased from 0% (0.0% to 0.2%) to 0.9% (0.3% to 2.4%).

CONCLUSIONS

The prevalence of severe asymptomatic carotid stenosis in the general population ranges from 0% to 3.1%, which is useful information in the discussion on the cost-effectiveness of screening.

Health disparities beginning in childhood: a life-course perspective

In this article we argue for the utility of the life-course perspective as a tool for understanding and addressing health disparities across socioeconomic and racial or ethnic groups, particularly disparities that originate in childhood. Key concepts and terms used in life-course research are briefly defined; as resources, examples of existing literature and the outcomes covered are provided along with examples of longitudinal databases that have often been used for life-course research. The life-course perspective focuses on understanding how early-life experiences can shape health across an entire lifetime and potentially across generations; it systematically directs attention to the role of context, including social and physical context along with biological factors, over time. This approach is particularly relevant to understanding and addressing health disparities, because social and physical contextual factors underlie socioeconomic and racial/ethnic disparities in health. A major focus of life-course epidemiology has been to understand how early-life experiences (particularly experiences related to economic adversity and the social disadvantages that often accompany it) shape adult health, particularly adult chronic disease and its risk factors and consequences. The strong life-course influences on adult health could provide a powerful rationale for policies at all levels--federal, state, and local--to give more priority to investment in improving the living conditions of children as a strategy for improving health and reducing health disparities across the entire life course.

Do socioeconomic gradients in subclinical atherosclerosis vary according to acculturation level? Analyses of Mexican-Americans in the multi-ethnic study of atherosclerosis

OBJECTIVE

To examine whether the association between socioeconomic position (SEP) and subclinical atherosclerosis in Mexican-Americans would be moderated by acculturation. Although SEP shows a consistent, inverse relationship with cardiovascular disease (CVD) risk in westernized non-Hispanic white populations, the relationship in ethnic minorities, including Hispanics, is often weak or even reversed (i.e., worse health with higher SEP).

METHODS

Participants were 801 Hispanics of Mexican origin (49.6% = female; average age = 60.47 years) from the Multi-Ethnic Study of Atherosclerosis cohort who underwent computed tomography of the chest for coronary artery calcium (CAC) and thoracic aortic calcium (TAC). SEP was represented by a composite of self-reported education and income. Acculturation was a composite score, including language spoken at home, generation, and years of "exposure" to U.S. culture.

RESULTS

Small but statistically significant SEP by acculturation interaction effects were identified in relation to prevalent CAC, prevalent TAC, and extent of TAC (all p < .05). Follow-up analyses revealed that the direction of the SEP gradient on detectable CAC changed as individuals progressed from low to high acculturation. Specifically, the association between SEP and calcification was positive at low levels of acculturation (i.e., a "reversed" gradient), and negative in circumstances of high acculturation (i.e., the expected, protective effect of higher SEP).

CONCLUSIONS

The findings support the utility of examining SEP and acculturation simultaneously, and of disaggregating large ethnic groupings (e.g., "Hispanic") into meaningful subgroups to better understand health risks.

Prevalence of asymptomatic carotid artery stenosis according to age and sex: systematic review and metaregression analysis

BACKGROUND AND PURPOSE

In the discussion on the value of population-wide screening for asymptomatic carotid artery stenosis (ACAS), reliable prevalence estimates are crucial. We set out to provide reliable age- and sex-specific prevalence estimates of ACAS through a systematic literature review and meta-regression analysis.

METHODS

We searched PubMed and EmBase until December 2007 for studies that reported the prevalence of ACAS in a population free of symptomatic carotid artery disease. Data were extracted with use of a standardized form on participants' characteristics, assessment method, study quality, and prevalence estimates for moderate (>or=50% stenosis) and severe (>or=70% stenosis) ACAS. Metaregression was used to investigate sources of heterogeneity.

RESULTS

Forty studies fulfilled the inclusion criteria. There was considerable variation among studies with respect to demographics, methods of grading stenosis, and stenosis cutoff point used. The pooled prevalence of moderate stenosis was 4.2% (95% CI, 3.1% to 5.7%). Prevalence of moderate stenosis among people age <70 years was 4.8% (95% CI, 3.1% to 7.3%) in men and 2.2% (95% CI, 0.9% to 4.9%) in women. Among those >or=70 years, prevalence increased to 12.5% (95% CI, 7.4% to 20.3%) in men and to 6.9% (95% CI, 4.0% to 11.5%) in women. Metaregression showed that both age and sex significantly affected the prevalence of moderate stenosis. No contribution of study size, publication year, geographic region, assessment method, and study quality was found. The pooled prevalence of severe stenosis was 1.7% (95% CI, 0.7% to 3.9%).

CONCLUSIONS

Prevalence of moderate stenosis increases with age in both men and women, but men at all ages have the higher prevalence estimates. The number of studies that allowed meaningful data synthesis of severe stenosis was limited.

Relationship of socioeconomic status to C-reactive protein and arterial stiffness in urban Japanese civil servants

This study investigates whether the two socioeconomic status indicators, educational level and employment grade, are associated with C-reactive protein (CRP) levels and arterial stiffness among Japanese urban civil servants. Brachial-ankle pulse-wave velocity (baPWV) as an indicator of arterial stiffness, CRP, occupational stress and conventional risk factors were evaluated in 3412 men and 854 women. Although the socioeconomic gradient showed a significant association with the CRP levels in men after adjustment for age, the significance disappeared after multivariate adjustment, whereas in women, the socioeconomic gradient showed no significant association with the CRP levels. In men, educational level was significantly associated with the baPWV value after adjustment for conventional risk factors, CRP and occupational stress (P for trend <0.0001). With regards to employment grade, only low-level non-manual workers had a significantly lower baPWV value as compared to manual workers at a fully adjusted model, and trend significance disappeared. However, in women, neither educational level nor employment grade was associated with the baPWV value. In summary, the socioeconomic gradient, especially the educational level, was significantly inversely related to the baPWV value in men. In women, the socioeconomic gradient was not related to the baPWV value. An inverse relationship between the socioeconomic gradient and CRP levels was found in men only after age adjustment. We suggest that because the educational level is an important aspect in the adolescent environment and hence might influence the future lifestyle, early health education should be provided to prevent an unfavourable lifestyle and atherosclerotic diseases in later life.

Effects of socioeconomic position on inflammatory and hemostatic markers: a life-course analysis in the 1958 British birth cohort

The cumulative effects of socioeconomic position (SEP) on cardiovascular disease have been described, but the pathways are unclear. In this study, the authors examined the effects of life-course SEP on inflammatory and hemostatic markers: fibrinogen, C-reactive protein, von Willebrand factor antigen, and tissue plasminogen activator antigen. Data from the 1958 British birth cohort, including data on persons who underwent a biomedical follow-up in 2002-2004, were used. Social class was determined at three stages of respondents' lives: childhood (birth), early adulthood (age 23 years), and midlife (age 42 years). A cumulative indicator score of SEP was calculated that ranged from 0 (always in the highest social class) to 9 (always in the lowest social class). In men and women, associations were observed between cumulative indicator score and fibrinogen (p < 0.001), C-reactive protein (p < 0.001), von Willebrand factor antigen (p < or = 0.05), and tissue plasminogen activator antigen (p < 0.001 only in women). The trends in fibrinogen and C-reactive protein remained after adjustment for body mass index, smoking, and physical activity. However, the trends became nonsignificant for von Willebrand factor antigen and tissue plasminogen activator antigen in women. Risk exposure related to SEP accumulates across the life course and contributes to raised levels of fibrinogen and C-reactive protein, while childhood SEP influences hemostatic markers more than does adult SEP.

The development of life course epidemiology

The present paper reviews the development of life course epidemiology since its origins during the 1990s from biological programming, birth cohort research and the study of health inequalities. Methods of studying the life course are examined, including birth cohort studies, linked register datasets and epidemiological archaeology. Three models of life course epidemiology are described: critical periods, accumulation, and pathways. Their conceptual and empirical differentiation can be difficult, but it is argued that accumulation is the underlying social process driving life course trajectories, while the critical period and pathway models are distinguished by their concern with specific types of aetiological process. Among the advantages of the accumulation model are predictive power, aetiological insights, contributions to health inequality debates and social policy implications. It is emphasised that the life course approach is not opposed to, or an alternative to, a concern with cross-sectional and current effects; major social disruption can have a large and immediate impact on health. Other limitations of the life course approach include a spectrum of impact (life course effects can be strong in relation to physiology, but often are weaker in relation to behaviour and psychological reactions to everyday life) and, more speculatively, the possibility that life course effects are diluted in the older age groups where morbidity and mortality are highest. Three issues for the future of life course epidemiology are identified. Many life course data are collected retrospectively. We need to know which items of information are recalled with what degree of accuracy over how many decades; and what methods of collecting these retrospective data maximise accuracy and duration. Second, the two partners in life course research need to take more seriously each other's disciplines. Social scientists need to be more critical of such measures as self-assessed health, which lacks an aetiology and hence biological plausibility. Natural scientists need to be more critical of such concepts as socio-economic status, which lacks social plausibility because it fails to distinguish between social location and social prestige. Finally, European comparative studies can play an important part in the future development of life course epidemiology if they build on the emerging infrastructure of European comparative research.

Job strain in men, but not in women, predicts a significant rise in blood pressure after 6.5 years of follow-up

BACKGROUND

Job strain (high demands and low decision latitude) has been associated with hypertension and cardiovascular disease, especially in men. Most studies on job strain and hypertension have been cross-sectional, and prospective data are inconsistent.

OBJECTIVE

To prospectively describe the effects of different psychosocial work characteristics on office blood pressure changes.

METHODS

In total, 448 men and women, mean age 55 years, were followed for a mean of 6.5 years. At baseline, work characteristics and cardiovascular risk factors were assessed. Only employed subjects aged 63 years or younger were eligible for participation.

RESULTS

Men with baseline job strain had a significantly greater increase in both systolic blood pressure (7.7 mmHg, P = 0.02), and diastolic blood pressure (5.6 mmHg, P = 0.003), compared to the group with low work demands and high decision latitude ('relaxed'). These findings were significant also after adjustments for age, follow-up time, baseline blood pressure, blood pressure treatment at baseline and follow-up, and length of education. Work demands were more strongly correlated with blood pressure increase than decision latitude. For women, no significant associations between psychosocial work characteristics and blood pressure changes were found, apart from a weak trend of association between increasing decision latitude and increasing blood pressure.

CONCLUSION

Job strain significantly predicts an increase in office blood pressure in middle-aged men, but not in women. Work demands were more strongly correlated with blood pressure increase than decision latitude in men.

A life-course approach to measuring socioeconomic position in population health surveillance systems

Measuring socioeconomic position (SEP) in population chronic disease and risk factor surveillance systems is essential for monitoring socioeconomic inequalities in health over time. Life-course measures are an innovative way to supplement other SEP indicators in surveillance systems. A literature review examined the indicators of early-life SEP that could potentially be used in population health surveillance systems. The criteria of validity, relevance, reliability and deconstruction were used to determine the value of potential indicators. Early-life SEP indicators used in cross-sectional and longitudinal studies included education level, income, occupation, living conditions, family structure and residential mobility. Indicators of early-life SEP should be used in routine population health surveillance to monitor trends in the health and SEP of populations over time, and to analyse long-term effects of policies on the changing health of populations. However, these indicators need to be feasible to measure retrospectively, and relevant to the historical, geographical and sociocultural context in which the surveillance system is operating.

Cumulative socioeconomic status across the life course and subclinical atherosclerosis

PURPOSE

The purpose of this study is to investigate the relationship between individual-level and neighborhood-level socioeconomic status (SES) across the life course and subclinical atherosclerosis.

METHODS

Participants from the Atherosclerosis Risk in Communities Study (n=12,332) were queried about individual-level SES and residential addresses across the life course. Individual-level measures were scored and summed to obtain a summary score (I-CumSES), whereas residential addresses were geocoded and linked to census data to obtain a summary neighborhood z score (N-CumSES) to evaluate the association of SES with intima-media thickness (IMT) and peripheral arterial disease (PAD).

RESULTS

A 1-SD lower I-CumSES was associated with greater mean IMT in each race-sex group and greater odds of PAD in white men (odds ratio [OR], 1.28; 95% confidence interval [CI], 0.99-1.64), white women (OR, 1.18; 95% CI, 1.02-1.36), and black women (OR, 1.33; 95% CI, 1.00-1.76). Compared with the highest tertile of N-CumSES, the lowest tertile was associated with greater mean IMT among whites, but was not associated with PAD for whites or blacks. When I-CumSES and N-CumSES were considered simultaneously, associations remained for only I-CumSES and were attenuated after adjustment for cardiovascular disease (CVD) risk factors.

CONCLUSIONS

Lower cumulative individual-level SES across the life course was associated with a greater burden of subclinical atherosclerosis, and this association was mediated in part by CVD risk factors.

Systematic Review of the Influence of Childhood Socioeconomic Circumstances on Risk for Cardiovascular Disease in Adulthood

PURPOSE

Adverse socioeconomic circumstances in childhood may confer a greater risk for adult cardiovascular disease (CVD). The purpose of this review is to systematically evaluate evidence for an association between socioeconomic circumstances during childhood and specific CVD subtypes, independent of adult socioeconomic conditions.

METHODS

We systematically retrieved individual-level studies of morbidity and mortality from CVD and specific CVD subtypes linked to early life influences, including coronary heart disease (CHD), ischemic and hemorrhagic stroke, peripheral vascular disease, markers of atherosclerosis (carotid intima-media thickness and stenosis), and rheumatic heart disease. Indicators of socioeconomic position in childhood varied, although most studies relied on father's occupation.

RESULTS

We located 40 studies (24 prospective, 11 case-control, and 5 cross-sectional) reported in 50 publications. Thirty-one studies (19 prospective, 7 case-control, and all 5 cross-sectional) found a robust inverse association between childhood circumstances and CVD risk, although findings sometimes varied among specific outcomes, socioeconomic measures, and sex. Case-control studies reported mixed results. The association was stronger for stroke and, in particular, hemorrhagic stroke, than for CHD. Childhood socioeconomic conditions remained important predictors of CVD, even in younger cohorts.

CONCLUSION

Childhood and adulthood socioeconomic circumstances are important determinants of CVD risk. The specific contribution of childhood and adulthood characteristics varies across different CVD subtypes. Disease-specific mechanisms are likely to explain the childhood origins of these adult health inequalities.

Socioeconomic differences in the progression of carotid atherosclerosis in middle-aged men and women with subclinical atherosclerosis in Sweden

While the persistence of socioeconomic differences in cardiovascular disease (CVD) has been recognized for many years, less is known about whether socioeconomic factors are of importance to CVD before symptoms of the disease appear. In this study the associations among educational level, occupational status and progression of atherosclerosis were investigated in 1016 Swedish middle-aged men and women with signs of subclinical atherosclerosis, i.e., carotid plaque (defined as focal intima-media thickness (IMT) > 1.2 mm). IMT in the common carotid artery (CCA) and in the carotid bifurcation area, as well as carotid plaque score, was determined by B-mode ultrasound. Results showed only weak associations between educational level, occupational status and age-, sex- and baseline IMT-adjusted progression of IMT in the CCA. However, in the age, sex- and baseline IMT-adjusted analyses, those in unskilled manual occupations showed a significantly higher yearly progression of carotid IMT in the bifurcation area compared to those in high- or medium-level non-manual occupations. Those with primary education tended to show a higher yearly progression of carotid IMT in the bifurcation area compared to those with completed secondary education. After adjustment for risk factors, the magnitude of these associations were somewhat attenuated. Similar patterns of associations were seen for the change of carotid plaque score. We conclude that low socioeconomic status (SES) is associated with progression of atherosclerosis in a middle-aged population with signs of subclinical atherosclerosis. Even though socioeconomic differences in cardiovascular risk factor levels could explain part of the found differences in progression rate in women, the mechanisms involved remain to be further established.

Socioeconomic position in childhood and adult cardiovascular risk factors, vascular structure, and function: cardiovascular risk in young Finns study

OBJECTIVE

To examine the association of childhood socioeconomic position (SEP) with adult cardiovascular risk factors, vascular structure, and vascular function in a contemporary population of young adults.

DESIGN

Population based prospective cohort study with baseline assessment in 1980.

SETTING

Finland.

PARTICIPANTS

856 men and 1066 women whose childhood SEP was determined by parental occupational status (manual, lower non-manual, upper non-manual) at age 3-18 years.

MAIN OUTCOME MEASURES

Cardiovascular risk factors, carotid artery intima-media thickness, and brachial artery flow mediated vasodilatation, assessed at age 24-39 years.

RESULTS

After adjustment for age and adult SEP, systolic pressure was 2.3 mm Hg higher (p = 0.0002), high density lipoprotein (HDL) cholesterol 0.03 mmol/l lower (p = 0.02), and insulin resistance score (homeostasis model assessment index) 0.12 units greater (p = 0.05) among men; and systolic pressure was 1.3 mm Hg higher (p = 0.02), diastolic pressure 1.1 mm Hg higher (p = 0.01), and height 1.1 cm lower (p < 0.0001) among women for each step down the childhood SEP hierarchy. Lower childhood SEP was associated with a 20% increase in the odds of having a waist circumference > 102 cm in men and > 88 cm in women (overall p = 0.05). Childhood SEP was not associated with intima-media thickness, flow mediated vasodilatation, the metabolic syndrome, low density lipoprotein cholesterol, triglycerides, body mass index, alcohol consumption, or smoking.

CONCLUSIONS

Among adults under 40, low childhood SEP predicted higher blood pressure and central obesity and, among men, unfavourable HDL cholesterol and insulin resistance, independent of current SEP. No independent effects were found on adult vascular structure, vascular function, or health related behaviours at this life stage.

Is the association between socioeconomic position and coronary heart disease stronger in women than in men?

The association between socioeconomic position and health is generally believed to be weaker among women than men. However, gender differences in the relation between socioeconomic position and coronary heart disease have not been evaluated in a representative sample of the US population. The authors examined this association in the First National Health and Nutrition Examination Survey (1971-1993), a longitudinal, representative study of the US population (n = 6,913). Information on educational attainment, household income, and covariates was derived from the baseline interview, and that on incident coronary heart disease was obtained from hospital records/death certificates over 22 years of follow-up. Cox's proportional hazards models showed that education and income were inversely associated with incident coronary heart disease in age-only and multivariate models. Risk associated with education varied by gender (p = 0.01), with less than high school education associated with stronger risk of coronary heart disease in women (relative risk = 2.15, 95% confidence interval: 1.46, 3.17) than in men (relative risk = 1.58, 95% confidence interval: 1.18, 2.12) in age-adjusted models. Low education was associated with greater social and psychological risks for women than men; however, metabolic risks largely explained gender differences in the educational gradient in coronary heart disease.

Childhood socioeconomic status and host resistance to infectious illness in adulthood

OBJECTIVE

Low childhood socioeconomic status (SES) is a risk factor for adult morbidity and mortality primarily attributable to cardiovascular disease. Here, we examine whether childhood SES is associated with adult host resistance to infectious illness, and whether the effect is limited to a critical period of low SES exposure, can be undone by changes in childhood SES, and is explained by adult SES.

METHODS

Three hundred thirty-four healthy volunteers reported their own and their parents' level of education and the ages during their childhood when their parents owned their homes. Volunteers' current home ownership was recorded from real estate records. Subsequently, they were given nasal drops containing 1 of 2 rhinoviruses and were monitored in quarantine for infection and signs/symptoms of a common cold.

RESULTS

For both viruses, susceptibility to colds decreased with the number of childhood years during which their parents owned their home (odds ratios by tertiles adjusted for demographics, body mass, season, and prechallenge viral-specific immunity were 3.7 for fewest years, 2.6 and 1). This decreased risk was attributable to both lower risk of infection and lower risk of illness in infected subjects. Moreover, those whose parents did not own their home during their early life but did during adolescence were at the same increased risk as those whose parents never owned their home. These associations were independent of parent education level, adult education and home ownership, and personality characteristics.

CONCLUSIONS

A marker of low income and wealth during early childhood is associated with decreased resistance to upper respiratory infections in adulthood. Higher risk is not ameliorated by higher SES during adolescence and is independent of adult SES.