Large-scale, population-based investigations primarily investigating the association between body mass index (BMI) and cardiovascular disease (CVD) mortality among older and younger adults in the United States (U.S.) are lacking. To evaluate the relationship between BMI and CVD mortality in older (≥65 years) and younger (<65 years) adults and to identify the nadir for CVD mortality. This cohort study used serial cross-sectional data from the 1997 to 2018 National Health Interview Survey (NHIS) linked with the National Death Index. NHIS is an annual nationally representative household interview survey of the civilian noninstitutionalized U.S. population. Residential units of the civilian noninstitutionalized population in the U.S. The target population for the NHIS is the civilian noninstitutionalized U.S. population at the time of the interview. We included all adults who had BMI data collected at 18 years and older and with mortality data being available. To minimize the risk of reverse causality, we excluded adults whose survival time was ≤2 years of follow-up after their initial BMI was recorded and those with prevalent cancer and/or CVD at baseline. We used the BMI record obtained in the year of the NHIS survey. Total CVD mortality used the NHIS data linked to the latest National Death Index data from the survey inception to December 31, 2019. We performed multivariable Cox proportional hazards regression models to estimate adjusted hazard ratios (aHRs) and 95 % confidence intervals (CIs). The study included 425,394 adults; the mean (SD) age was 44 (16.7) years. During a median follow-up period of 11 years, 12,089 CVD-related deaths occurred. In older adults, having overweight was associated with a lower risk of CVD mortality (aHR 0.92 [95 % CI, 0.87–0.97]); having class I obesity (1.04 [0.97–1.12]) and class II obesity (1.12 [1.00–1.26]) was not significantly associated with an increased CVD mortality; and having class III obesity was associated with an increased risk of CVD mortality (1.63 [1.35–1.98]), in comparison with adults who had a normal BMI. Yet, in younger adults, having overweight, class I, II, and III obesity was associated with a progressively higher risk of CVD mortality. The nadir for CVD mortality is 28.2 kg/m in older adults and 23.6 kg/m in younger adults. This U.S. population-based cohort study highlights the significance of considering age as a crucial factor when providing recommendations and delivering self-care educational initiatives for weight loss to reduce CVD mortality.

中文翻译：

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美国老年人心血管死亡率的肥胖悖论：一项使用 1997-2018 年国家健康访谈调查数据与国家死亡指数相关的队列研究


目前还缺乏大规模、以人群为基础的调查，主要调查美国老年人和年轻人的体重指数 (BMI) 与心血管疾病 (CVD) 死亡率之间的关系。评估老年（≥65 岁）和年轻（<65 岁）成年人的 BMI 与 CVD 死亡率之间的关系，并确定 CVD 死亡率的最低点。这项队列研究使用了 1997 年至 2018 年国家健康访谈调查 (NHIS) 与国家死亡指数相关的连续横断面数据。 NHIS 是对美国非机构化平民人口进行的年度全国代表性家庭访谈调查。美国非机构化平民人口的住宅单位 NHIS 的目标人群是访谈时非机构化美国平民人口。我们纳入了所有在 18 岁及以上收集了 BMI 数据并且有可用死亡率数据的成年人。为了尽量减少反向因果关系的风险，我们排除了记录初始 BMI 后随访生存时间≤2 年的成年人以及基线时患有普遍癌症和/或 CVD 的成年人。我们使用了 NHIS 调查当年获得的 BMI 记录。 CVD 总死亡率使用与从调查开始到 2019 年 12 月 31 日的最新国家死亡指数数据相关的 NHIS 数据。我们使用多变量 Cox 比例风险回归模型来估计调整后的风险比 (aHR) 和 95% 置信区间 (CI)。该研究包括 425,394 名成年人；平均 (SD) 年龄为 44 (16.7) 岁。在 11 年的中位随访期内，发生了 12,089 例与 CVD 相关的死亡。在老年人中，超重与较低的 CVD 死亡风险相关（aHR 0.92 [95% CI，0.87-0.97]）；患有 I 级肥胖 (1.04 [0.97–1.12]) 和 II 级肥胖 (1.12 [1.00–1.26]) 与 CVD 死亡率增加没有显着相关性；与 BMI 正常的成年人相比，III 级肥胖与 CVD 死亡风险增加相关（1.63 [1.35–1.98]）。然而，在年轻人中，超重、I、II 和 III 级肥胖与 CVD 死亡风险逐渐升高相关。老年人 CVD 死亡率最低为 28.2 公斤/平方米，年轻人为 23.6 公斤/平方米。这项基于美国人口的队列研究强调了在提供减肥建议和自我保健教育举措以降低心血管疾病死亡率时将年龄视为关键因素的重要性。