The Socioeconomic Gradient in the Incidence of Stroke

Abstract

Background and Purpose-A socioeconomic gradient in stroke has been demonstrated in a variety of settings, but mostly in men. Our purpose was to establish whether a socioeconomic gradient in stroke existed in a group of Swedish women and whether this gradient could be explained by established stroke risk factors or psychosocial factors. Methods-The Women's Lifestyle and Health Cohort Study includes 49 259 women from Sweden aged 30 to 50 years at baseline (1991 to 1992). The women completed an extensive questionnaire and were traced through linkages to national registries until the end of 2002. Among the 47 942 women included in these analyses, there were 200 cases of incident stroke during follow up (121 ischemic stroke, 47 hemorrhagic stroke, and 32 of unknown origin). Statistical analysis was through the Cox proportional hazards model. Results-The risk of stroke was significantly inversely related to years of education completed, our proxy for socioeconomic status (hazard ratio comparing lowest with highest education groupϭ2.1, 95% CI: 1.4 to 2.9, P for trend Ͻ0.001). This association was reduced after adjustment for established risk factors, although remaining significant (1.5, 1.0 to 2.2, P for trendϭ0.04). The gradient was more pronounced for ischemic stroke (2.9, 1.8 to 4.7, P for trend Ͻ0.001) than for hemorrhagic stroke (1.4, 0.7 to 2.9, P for trendϭ0.35). Job strain and social support were unrelated to risk of stroke. Self-rated health was strongly related to risk of stroke mediated by established risk factors. Psychosocial factors did not contribute toward the socioeconomic gradient in stroke. Conclusions-There was a strong gradient in risk of stroke by years of education, especially for ischemic stroke. Most of the social gradient was explained by established risk factors, particularly smoking and alcohol, but not by psychosocial factors.

Demographic Factors and Risk Indicators of Stroke: Comparison Between Inhabitants of Fortaleza Municipal District and the National Profile

“…participants identified a strong relationship between the incidence of stroke and years of schooling, showing that the incidence was two times higher among people with a low education (22) .…”

Psychosocial work environment and risk of ischemic stroke and coronary heart disease: a prospective longitudinal study of 75 236 construction workers

“…This is somewhat in line with previous studies. Regarding high strain, two longitudinal studies have shown non-significant results with mostly marginally increased risk estimates (13,18), and in another two studies there was moderately, still non-significant, increased risk (14,19). In a Japanese study there are quite high risk estimates for most dimensions of the JDC model, although only significant for high strain in all types of stroke (21).…”

“…All items were scored using a scale (1-5) ranging from "seldom" to "often". Job control consisted of three items (range 3-15), job demand of four items (range [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], and social support of two items (range 2-10). In order to reduce the amount of missing data, control and demand were imputed using the mean of the remaining values for subjects with only one missing item.…”

“…Low socioeconomic status has consistently been identified as a predictor of stroke (15,19,22,23). It has also been found that JDC strengthens the effect of socioeconomic status rather than explains it (14).…”

“…There are only a handful studies that use the joint JDC model with four categories to examine the association between psychosocial work environment and stroke (13,14,(19)(20)(21). Only one (21) displayed significant increased risks for high strain jobs.…”