Effect of duration and age at exposure to the Stroke Belt on incident stroke in adulthood

Abstract

Objective: To assess whether there are differences in the strength of association with incident stroke for specific periods of life in the Stroke Belt (SB).Methods: The risk of stroke was studied in 24,544 black and white stroke-free participants, aged 451, in the Reasons for Geographic and Racial Differences in Stroke study, a national populationbased cohort enrolled [2003][2004][2005][2006][2007]. Incident stroke was defined as first occurrence of stroke over an average 5.8 years of follow-up. Residential histories (city/state) were obtained by questionnaire. SB exposure was quantified by combinations of SB birthplace and current residence and proportion of years in SB during discrete age categories (0-12, 13-18, 19-30, 31-45, last 20 years) and entire life. Proportional hazards models were used to establish association of incident stroke with indices of exposure to SB, adjusted for demographic, socioeconomic (SES), and stroke risk factors.Results: In the demographic and SES models, risk of stroke was significantly associated with proportion of life in the SB and with all other exposure periods except birth, ages 31-45, and current residence. The strongest association was for the proportion of the entire life in SB. After adjustment for risk factors, the risk of stroke remained significantly associated only with proportion of residence in SB in adolescence (hazard ratio 1.17, 95% confidence interval 1.00-1.37).Conclusions: Childhood emerged as the most important period of vulnerability to SB residence as a predictor of future stroke. Improvement in childhood health circumstances should be considered as part of long-term health improvement strategies in the SB. The Stroke Belt region (SB) in the southeastern United States has higher stroke mortality than the rest of the United States, 1,2 and national data suggest that similar regional differences exist in stroke incidence. [3][4][5][6] There are several hypothesized reasons for this but data for testing the underlying factors are limited. 2 Research to date has shown that only a portion of the higher stroke mortality can be explained by traditional risk factors.7-10 SB has been defined using state of residence at time of death. Population migration may contribute to differences in regional mortality rates but few US studies have considered the impact of population redistribution on geographic disparities in stroke incidence and mortality.11-14 Some, 12-14 but not all, 11 studies have shown that birthplace is associated with cardiovascular mortality, with individuals born in the Southeast having higher rates than those born in other regions of the United States. With respect to stroke incidence, one national study showed increased incidence of self-reported stroke associated with living in the SB during childhood. 6 It is not known whether there is a "sensitive period" for residence in the SB, i.e., a developmental period during which SB exposure has the greatest consequences for later stroke risk, or whether stroke risk accumulates with each additiona...

Nontraditional Risk Factors for Ischemic Stroke

“…One recent study showed that the risk of stroke was associated with the proportion of residence in stroke belt in adolescence, suggesting the importance of childhood health circumstances in long-term stroke risk. 106 Further studies are needed evaluating risk factors during early in the life. Social efforts are mandatory to control nontraditional risk factors (eg, childhood obesity) and triggering factors (eg, air pollution), whereas control of traditional risk factor could be basically clinic base.…”

Eligibility for cardiovascular risk screening among different ethnic groups: The HELIUS study

“…This is likely to contribute to ethnic differences in CVD, as prolonged exposure to hypertension increases cardiovascular risk. 20,21 Ethnic-specific age thresholds to initiate screening may be required to reduce these differences.…”

“…by taking into account the duration of exposure to cardiovascular risk factors, thereby taking into account ethnic differences in the age-of-onset of cardiovascular risk factors). 20,21,24 In this study, we used The Netherlands as a European example to show how ethnic groups may differ in the age to initiate CVD risk screening. Earlier work has shown that ethnic differences in cardiovascular risk factors in The Netherlands are comparable to ethnic differences in other countries, although the magnitude of differences may vary between countries.…”

Women's Health: Racial and Ethnic Health Inequities

“…For example, birthplace has been associated with cardiovascular mortality, 16 , 17 and adolescents who reside in the stroke belt are at an increased risk of stroke in adulthood. 18 Children who reside in neighborhoods that are economically poor and have low levels of education have an increased risk for obesity regardless of their individual characteristics. 19 Alternatively, living in low-poverty neighborhoods and in neighborhoods with reasonable proximity to supermarkets has been associated with less obesity.…”