Falls are a leading cause of head injury among older adults, but the risk of fall occurring after a head injury is less well-characterized. We sought to examine the association between head injury and subsequent risk of falls requiring hospital care among community-dwelling older adults.

This analysis included 13,081 participants in the Atherosclerosis Risk in Communities Study enrolled in 1987–1989 and followed through 2019. The association of head injury (time-varying exposure, self-reported and/or ICD-9/10 code identified) with the risk of subsequent (occurring >1-month after head injury) falls requiring hospital care (ICD-9/10 code defined) was modeled using Cox proportional hazards regression. Secondary analyses included Fine and Gray proportional hazards regression to account for the competing risk of death, analysis of head injury frequency and severity, and formal testing for interaction by age, sex, and race. Models were adjusted for age, sex, race/center, education, military service, alcohol consumption, smoking, diabetes, hypertension, and psychotropic medication use.

The mean age of participants at baseline was 54 years, 58% were female, 28% were Black, and 14% had at least one head injury occurring over the study period. Over a median 23 years of follow-up, 29% of participants had a fall requiring medical care. In adjusted Cox proportional hazards models, individuals with head injury had 2.01 (95% CI 1.85–2.18) times the risk of falls compared with individuals without head injury. Accounting for the competing risk of mortality, individuals with head injury had 1.69 (95% CI 1.57–1.82) times the risk of falls compared with individuals without head injury. We observed stronger associations among men compared with women (men: hazard ratio [HR] = 2.60, 95% CI 2.25–3.00; women: HR = 1.80, 95% CI 1.63–1.99, p-interaction <0.001). We observed evidence of a dose-response association for head injury number and severity with fall risk (1 injury: HR = 1.68, 95% CI 1.53–1.84; 2+ injuries: HR = 2.37, 95% CI 1.92–2.94 and mild: HR = 1.97, 95% CI 1.78–2.18; moderate/severe/penetrating: HR = 2.50, 95% CI 2.06–3.02).

Among community-dwelling older adults followed over 30 years, head injury was associated with subsequent falls requiring medical care. We observed stronger associations among men and with increasing number and severity of head injuries. Whether older individuals with head injury might benefit from fall prevention measures should be a focus of future research.

跌倒是老年人头部受伤的主要原因，但头部受伤后发生跌倒的风险尚不清楚。我们试图研究社区老年人头部受伤与随后需要住院治疗的跌倒风险之间的关系。

该分析纳入了 1987 年至 1989 年参与动脉粥样硬化风险社区研究并跟踪至 2019 年的 13,081 名参与者。头部损伤（随时间变化的暴露、自我报告和/或识别的 ICD-9/10 代码）与风险的关联使用 Cox 比例风险回归对随后（头部受伤后 1 个月以上发生）跌倒需要医院护理（定义的 ICD-9/10 代码）进行建模。二次分析包括精细和灰色比例风险回归，以解释死亡的竞争风险，分析头部受伤频率和严重程度，以及按年龄、性别和种族进行相互作用的正式测试。模型根据年龄、性别、种族/中心、教育、服兵役、饮酒、吸烟、糖尿病、高血压和精神药物的使用进行了调整。

参与者的基线平均年龄为 54 岁，其中 58% 为女性，28% 为黑人，14% 在研究期间至少发生过一次头部受伤。在平均 23 年的随访中，29% 的参与者曾跌倒，需要医疗护理。在调整后的 Cox 比例风险模型中，与没有头部受伤的个体相比，头部受伤的个体跌倒的风险是其 2.01 (95% CI 1.85–2.18) 倍。考虑到死亡的竞争风险，头部受伤的人跌倒的风险是没有头部受伤的人的 1.69 (95% CI 1.57–1.82) 倍。我们观察到男性与女性之间的相关性更强（男性：风险比 [HR] = 2.60，95% CI 2.25–3.00；女性：HR = 1.80，95% CI 1.63–1.99，p交互作用 <0.001）。我们观察到头部受伤次数和严重程度与跌倒风险之间存在剂量反应关系的证据（1 次受伤：HR = 1.68，95% CI 1.53–1.84；2 次以上受伤：HR = 2.37，95% CI 1.92–2.94 和轻度： HR = 1.97，95% CI 1.78–2.18；中度/重度/穿透：HR = 2.50，95% CI 2.06–3.02）。

在对社区居住的老年人进行了 30 多年的跟踪调查后，发现头部受伤与随后需要医疗护理的跌倒有关。我们观察到男性之间的关联性更强，并且与头部受伤的数量和严重程度增加有关。头部受伤的老年人是否可以从跌倒预防措施中受益应该是未来研究的重点。