Background and Aims Longitudinal change in income is crucial in explaining cardiovascular health inequalities. However, there is limited evidence for cardiovascular disease (CVD) risk associated with income dynamics over time among individuals with type 2 diabetes (T2D). Methods Using a nationally representative sample from the Korean National Health Insurance Service database, 1 528 108 adults aged 30–64 with T2D and no history of CVD were included from 2009 to 2012 (mean follow-up of 7.3 years). Using monthly health insurance premium information, income levels were assessed annually for the baseline year and the four preceding years. Income variability was defined as the intraindividual standard deviation of the percent change in income over 5 years. The primary outcome was a composite event of incident fatal and nonfatal CVD (myocardial infarction, heart failure, and stroke) using insurance claims. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated after adjusting for potential confounders. Results High-income variability was associated with increased CVD risk (HRhighest vs. lowest quartile 1.25, 95% CI 1.22–1.27; Ptrend < .001). Individuals who experienced an income decline (4 years ago vs. baseline) had increased CVD risk, which was particularly notable when the income decreased to the lowest level (i.e. Medical Aid beneficiaries), regardless of their initial income status. Sustained low income (i.e. lowest income quartile) over 5 years was associated with increased CVD risk (HRn = 5 years vs. n = 0 years 1.38, 95% CI 1.35–1.41; Ptrend < .0001), whereas sustained high income (i.e. highest income quartile) was associated with decreased CVD risk (HRn = 5 years vs. n = 0 years 0.71, 95% CI 0.70–0.72; Ptrend < .0001). Sensitivity analyses, exploring potential mediators, such as lifestyle-related factors and obesity, supported the main results. Conclusions Higher income variability, income declines, and sustained low income were associated with increased CVD risk. Our findings highlight the need to better understand the mechanisms by which income dynamics impact CVD risk among individuals with T2D.

中文翻译：

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糖尿病患者的收入变异性和心血管疾病发生率：一项基于人群的队列研究


背景和目标 收入的纵向变化对于解释心血管健康不平等至关重要。然而，关于 2 型糖尿病 (T2D) 患者随时间推移的收入动态与心血管疾病 (CVD) 风险相关的证据有限。方法 使用韩国国民健康保险服务数据库中的全国代表性样本，纳入 2009 年至 2012 年间 1 528 108 名 30-64 岁患有 T2D 且无 CVD 病史的成年人（平均随访时间为 7.3 年）。使用每月健康保险保费信息，每年评估基准年和前四年的收入水平。收入变异性定义为 5 年内收入百分比变化的个体内标准差。主要结局是使用保险索赔的致命和非致命CVD（心肌梗塞、心力衰竭和中风）事件的复合事件。在调整潜在的混杂因素后估计风险比 (HR) 和 95% 置信区间 (CI)。结果 高收入变异性与 CVD 风险增加相关（HRhighest vs. 最低四分位数 1.25，95% CI 1.22–1.27；Ptrend < .001）。经历收入下降（4 年前与基线相比）的个人 CVD 风险增加，当收入下降到最低水平（即医疗援助受益人）时，无论其初始收入状况如何，这一点尤其显着。 5 年以上持续低收入（即最低收入四分位）与 CVD 风险增加相关（HRn = 5 年 vs. n = 0 年 1.38，95% CI 1.35–1.41；Ptrend < .0001），而持续高收入（ （即最高收入四分位数）与 CVD 风险降低相关（HRn = 5 年 vs. n = 0 年 0.71，95% CI 0.70–0.72；Ptrend < .0001）。 敏感性分析，探索潜在的调节因素，如生活方式相关因素和肥胖，支持了主要结果。结论 较高的收入波动、收入下降和持续的低收入与 CVD 风险增加相关。我们的研究结果强调需要更好地了解收入动态影响 T2D 患者 CVD 风险的机制。