OBJECTIVE Black Americans have a greater risk of type 2 diabetes than White Americans. The proinflammatory cytokine interleukin-6 (IL-6) is implicated in diabetes pathogenesis, and IL-6 levels are higher in Black individuals. This study investigated associations of IL-6 with incident diabetes and metabolic syndrome in a biracial cohort. RESEARCH DESIGN AND METHODS The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study enrolled 30,239 Black and White adults age ≥45 years in 2003–2007, with a follow-up ∼9.5 years later. Baseline plasma IL-6 was measured in 3,399 participants at risk of incident diabetes and 1,871 at risk of metabolic syndrome. Relative risk (RR) by IL-6 was estimated with modified Poisson regression for both groups. RESULTS Incident diabetes occurred in 14% and metabolic syndrome in 20%; both rates rose across IL-6 quartiles. There was a three-way interaction of IL-6, race, and central adiposity for incident diabetes (P = 8 × 10−5). In Black participants with and without central adiposity, RRs were 2.02 (95% CI 1.00–4.07) and 1.66 (1.00–2.75) for the fourth compared with first IL-6 quartile, respectively. The corresponding RRs were 1.73 (0.92–3.26) and 2.34 (1.17–4.66) in White participants. The pattern was similar for IL-6 and metabolic syndrome. CONCLUSIONS Although IL-6 was higher in Black than in White participants and those with central adiposity, the association of IL-6 with diabetes risk was statistically significant only among White participants without central adiposity. The association with metabolic syndrome risk was similarly stronger in low-risk groups. The results support the concept of interventions to lower inflammation in diabetes prevention, but to reduce race disparities, better biomarkers are needed.

中文翻译：

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双种族队列中的白细胞介素 6、糖尿病和代谢综合征：中风队列中地理和种族差异的原因

目的 美国黑人比美国白人患 2 型糖尿病的风险更大。促炎细胞因子白细胞介素 6 (IL-6) 与糖尿病发病机制有关，并且黑人个体中的 IL-6 水平较高。本研究在一个混血儿队列中调查了 IL-6 与糖尿病和代谢综合征发生的关联。研究设计和方法 中风地理和种族差异的原因 (REGARDS) 研究在 2003 年至 2007 年招募了 30,239 名年龄≥45 岁的黑人和白人成年人，并在 9.5 年后进行了随访。对 3,399 名有糖尿病风险的参与者和 1,871 名有代谢综合征风险的参与者测量了基线血浆 IL-6。IL-6 的相对风险 (RR) 通过改良泊松回归对两组进行估计。结果 糖尿病发病率为 14%，代谢综合征发病率为 20%；IL-6 四分位数的两个比率均有所上升。IL-6、种族和中心性肥胖与糖尿病发生率之间存在三向相互作用（P = 8 × 10−5）。在有或没有中心性肥胖的黑人参与者中，与第一个 IL-6 四分位数相比，第四个四分位数的 RR 分别为 2.02 (95% CI 1.00–4.07) 和 1.66 (1.00–2.75)。白人参与者的相应 RR 为 1.73 (0.92–3.26) 和 2.34 (1.17–4.66)。IL-6 和代谢综合征的模式相似。结论 虽然黑人的 IL-6 水平高于白人参与者和中心性肥胖者，但 IL-6 与糖尿病风险的关联仅在没有中心性肥胖的白人参与者中具有统计学意义。在低风险人群中，与代谢综合征风险的相关性同样更强。结果支持了在糖尿病预防中降低炎症的干预措施的概念，但为了减少种族差异，需要更好的生物标志物。