Objective

Investigate whether socioeconomic status (SES) was related to brain volume in aging related regions, and if so, determine whether this relationship was mediated by lifestyle factors that are known to associate with risk of dementia in a population-based sample of community dwelling middle-aged adults.

Methods

We studied 645 (41% black) participants (mean age 55.3±3.5) from the Coronary Artery Risk Development in Young Adults (CARDIA) study who underwent brain magnetic resonance imaging. SES was operationalized as a composite measure of annual income and years of education. Gray matter volume was estimated within the insular cortex, thalamus, cingulate, frontal, inferior parietal, and lateral temporal cortex. These regions are vulnerable to age-related atrophy captured by the Spatial Pattern of Atrophy for Recognition of Brain Aging (SPARE-BA) index. Lifestyle factors of interest included physical activity, cognitive activity (e.g. book/newspaper reading), smoking status, alcohol consumption, and diet. Multivariable linear regressions tested the association between SES and brain volume. Sobel mediation analyses determined if this association was mediated by lifestyle factors. All models were age, sex, and race adjusted.

Results

Higher SES was positively associated with brain volume (β = .109 SE = .039; p < .01) and smoking status significantly mediated this relationship (z = 2.57). With respect to brain volume, smoking accounted for 27% of the variance (β = -.179 SE = .065; p < .01) that was previously attributed to SES.

Conclusion

Targeting smoking cessation could be an efficacious means to reduce the health disparity of low SES on brain volume and may decrease vulnerability for dementia.

中文翻译：

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吸烟介导了SES与脑容量之间的关系：CARDIA研究。

目的

调查社会经济状况（SES）是否与衰老相关区域的大脑容量有关，如果有，确定这种关系是否由已知与痴呆症风险相关的生活方式因素介导，该样本是基于人群的社区居住中老年人。

方法

我们研究了645例（41％的黑人）参与者（平均年龄55.3±3.5），这些参与者接受了脑磁共振成像的年轻人（冠状动脉）风险发展研究。SES作为年收入和受教育年限的综合衡量指标而投入运营。估计灰质的体积在岛上皮层，丘脑，扣带状，额叶，顶下壁和外侧颞叶皮层内。这些区域很容易因识别脑老化的萎缩空间格局（SPARE-BA）指数而捕获的与年龄相关的萎缩。感兴趣的生活方式因素包括体育锻炼，认知活动（例如，阅读书/报纸），吸烟状况，饮酒和饮食。多变量线性回归测试了SES与脑容量之间的关系。Sobel调解分析确定这种联系是否由生活方式因素介导。所有模型都对年龄，性别和种族进行了调整。

结果

较高的SES与脑容量正相关（β= .109 SE = .039；p <.01），吸烟状态显着介导了这种关系（z = 2.57）。就脑容量而言，吸烟占先前归因于SES的方差的27％（β= -.179 SE = .065；p <.01）。

结论

以戒烟为目标可能是减少低SES对大脑容量的健康差异并减少痴呆症易感性的有效手段。