San Francisco Veterans Affairs Health Care System, San Francisco, California.
Department of Psychiatry, University of California, San Francisco.
JAMA Neurol. 2018 Sep 1;75(9):1055-1061. doi: 10.1001/jamaneurol.2018.0815.
Traumatic brain injury (TBI) is common in both veteran and civilian populations. Prior studies have linked moderate and severe TBI with increased dementia risk, but the association between dementia and mild TBI, particularly mild TBI without loss of consciousness (LOC), remains unclear.
To examine the association between TBI severity, LOC, and dementia diagnosis in veterans.
DESIGN, SETTING, AND PARTICIPANTS: This cohort study of all patients diagnosed with a TBI in the Veterans Health Administration health care system from October 1, 2001, to September 30, 2014, and a propensity-matched comparison group. Patients with dementia at baseline were excluded. Researchers identified TBIs through the Comprehensive TBI Evaluation database, which is restricted to Iraq and Afghanistan veterans, and the National Patient Care Database, which includes veterans of all eras. The severity of each TBI was based on the most severe injury recorded and classified as mild without LOC, mild with LOC, mild with LOC status unknown, or moderate or severe using Department of Defense or Defense and Veterans Brain Injury Center criteria. International Classification of Diseases, Ninth Revision codes were used to identify dementia diagnoses during follow-up and medical and psychiatric comorbidities in the 2 years prior to the index date.
Dementia diagnosis in veterans who had experienced TBI with or without LOC and control participants without TBI exposure.
The study included 178 779 patients diagnosed with a TBI in the Veterans Health Administration health care system and 178 779 patients in a propensity-matched comparison group. Veterans had a mean (SD) age of nearly 49.5 (18.2) years at baseline; 33 250 (9.3%) were women, and 259 136 (72.5%) were non-Hispanic white individuals. Differences between veterans with and without TBI were small. A total of 4698 veterans (2.6%) without TBI developed dementia compared with 10 835 (6.1%) of those with TBI. After adjustment for demographics and medical and psychiatric comobidities, adjusted hazard ratios for dementia were 2.36 (95% CI, 2.10-2.66) for mild TBI without LOC, 2.51 (95% CI, 2.29-2.76) for mild TBI with LOC, 3.19 (95% CI, 3.05-3.33) for mild TBI with LOC status unknown, and 3.77 (95% CI, 3.63-3.91) for moderate to severe TBI.
In this cohort study of more than 350 000 veterans, even mild TBI without LOC was associated with more than a 2-fold increase in the risk of dementia diagnosis. Studies of strategies to determine mechanisms, prevention, and treatment of TBI-related dementia in veterans are urgently needed.
创伤性脑损伤（TBI）在退伍军人和普通人群中都很常见。先前的研究已经将中度和重度 TBI 与痴呆风险增加联系起来，但轻度 TBI（尤其是无意识丧失的轻度 TBI，简称 mTBI-LOC）与痴呆之间的关联仍不清楚。
研究退伍军人中 TBI 严重程度、意识丧失（LOC）与痴呆诊断之间的关系。
设计、地点和参与者：这是一项对退伍军人健康管理系统中 2001 年 10 月 1 日至 2014 年 9 月 30 日期间被诊断为 TBI 的所有患者以及匹配的对照组患者进行的队列研究。排除了基线时患有痴呆症的患者。研究人员通过限定于伊拉克和阿富汗退伍军人的综合性脑损伤评估数据库和包含各时期退伍军人的国家患者护理数据库来确定 TBI。根据记录的最严重损伤程度，将 TBI 分为无 LOC 的轻度、有 LOC 的轻度、LOC 状态不明的轻度、中度或重度 TBI，并采用国防部或国防和退伍军人脑损伤中心的标准。使用国际疾病分类第 9 版（ICD-9）编码在随访期间识别痴呆症诊断，并在指数日期前 2 年内识别医疗和精神共病。
比较经历过 TBI 或无 TBI 暴露的退伍军人与未暴露于 TBI 的对照组退伍军人中的痴呆症诊断。
该研究纳入了退伍军人健康管理系统中被诊断为 TBI 的 178779 名患者和匹配的对照组中 178779 名患者。退伍军人的基线平均（SD）年龄为近 49.5（18.2）岁；33250 名（9.3%）为女性，259136 名（72.5%）为非西班牙裔白人。有 TBI 和无 TBI 的退伍军人之间的差异很小。在无 TBI 的退伍军人中，有 4698 人（2.6%）发生了痴呆症，而有 TBI 的退伍军人中，有 10835 人（6.1%）发生了痴呆症。在调整了人口统计学因素、医疗和精神共病因素后，无 LOC 的轻度 TBI 的调整后痴呆症风险比为 2.36（95%CI，2.10-2.66），有 LOC 的轻度 TBI 为 2.51（95%CI，2.29-2.76），LOC 状态不明的轻度 TBI 为 3.19（95%CI，3.05-3.33），中度至重度 TBI 为 3.77（95%CI，3.63-3.91）。
在这项对超过 350000 名退伍军人的队列研究中，即使是无 LOC 的轻度 TBI 也与痴呆症诊断风险增加一倍以上相关。迫切需要开展研究，以确定退伍军人中与 TBI 相关的痴呆症的机制、预防和治疗策略。
