Importance Determining whether the previously reported decreased stroke incidence rates from 1987 to 2011 among US adults 65 years and older in the Atherosclerosis Risk in Communities (ARIC) study continued to decrease subsequently can help guide policy and planning efforts.

Objective To evaluate whether stroke incidence declines among older adults in the ARIC study continued after 2011.

Design, Setting, and Participants ARIC is a community-based prospective cohort study including 15 792 individuals aged 45 to 64 years at baseline (1987-1989), selected by probability sampling from residents of Forsyth County, North Carolina; Jackson, Mississippi (black individuals only); the northwestern suburbs of Minneapolis, Minneapolis; and Washington County, Maryland (ie, center). The present study included ARIC participants free of stroke at baseline, followed up through December 31, 2017. Data were collected through personal interviews and physical examinations during study visits, annual/semiannual telephone interviews, and active surveillance of discharges from local hospitals. Stroke events were adjudicated by study-physicians reviewers. Analysis began September 2018.

Main Outcomes and Measures The main outcome was stroke incidence rates, which were computed with 95% CIs stratifying the analysis by age and calendar time. Trends in adjusted incidence rates were assessed using Poisson regression incidence rate ratios. Models included calendar time, age, sex, race/center, and time-varying risk factors (hypertension, diabetes, coronary heart disease, cholesterol-lowering medication use, and smoking).

Results Of 14 357 ARIC participants with 326 654 person-years of follow-up, the mean (SD) age at baseline was 54.1 (5.8) years and 7955 (55.4%) were women. From 1987 to 2017, a total of 1340 incident strokes occurred among ARIC participants, and among them, 1028 (76.7%) occurred in participants 65 years and older. Crude incidence rates of stroke for participants 65 years and older decreased progressively from 1987 to 2017. Incidence rates, adjusted for age, sex, race/center, and time-varying risk factors, decreased by 32% (95% CI, 23%-40%) per 10 years in participants 65 years and older. Findings were consistent across decades, sex, and race.

Conclusions and Relevance Validated total stroke incidence rates in adults 65 years and older decreased over the last 30 years in the ARIC cohort. The decrease in rates previously reported for 1987 to 2011 extends for the subsequent 6 years in men and women as well as in white and black individuals.

重要性 在随后的社区动脉粥样硬化风险（ARIC）研究中，确定先前报道的1987年至2011年美国65岁及以上成年人中风发病率是否下降，可以继续帮助指导政策和规划工作。

目的 在2011年后继续进行的ARIC研究中评估老年人中风发生率是否下降。

设计，设置和参与者 ARIC是一项基于社区的前瞻性队列研究，包括基线（1987-1989年）的15792名年龄在45至64岁之间的人，这些人是通过概率抽样从北卡罗来纳州福赛斯县的居民中选出的。密西西比州杰克逊（仅黑人）；明尼阿波利斯的明尼阿波利斯西北郊区；和马里兰州华盛顿县（即中心）。本研究包括基线时无卒中的ARIC参与者，并随访至2017年12月31日。数据通过研究访问期间的个人访谈和体格检查，年度/半年电话访谈以及对当地医院出院情况的主动监视来收集。中风事件由研究医师审阅者裁定。分析于2018年9月开始。

主要结果和衡量指标 主要结果是中风发生率，其中95％CI分别按年龄和日历时间对分析进行了分层计算。使用泊松回归发生率比率评估调整后发生率的趋势。模型包括日历时间，年龄，性别，种族/中心和随时间变化的风险因素（高血压，糖尿病，冠心病，降低胆固醇的药物使用和吸烟）。

结果 在14 357名ARIC参与者中，有326 654人年的随访，基线时的平均（SD）年龄为54.1（5.8）岁，女性为7955（55.4％）。从1987年到2017年，ARIC参与者总共发生了1340起中风，其中65岁及以上的参与者发生了1028起（76.7％）。从1987年到2017年，65岁及65岁以上参与者的中风粗发病率逐渐降低。根据年龄，性别，种族/中心和随时间变化的危险因素进行调整后，发病率下降了32％（95％CI，23％- 65岁及以上的参与者每10年40％）。在数十年，性别和种族之间的发现都是一致的。

结论和相关性 在过去30年中，ARIC队列中65岁及65岁以上成年人的有效总卒中发生率有所下降。先前报告的1987年至2011年比率的下降在随后的6年中一直延续到男性和女性以及白人和黑人。