The effect of influenza vaccination on the rate of dementia amongst older adults

IF 4.5 2区医学 Q1 CLINICAL NEUROLOGY

European Journal of Neurology Pub Date : 2024-10-06 DOI:10.1111/ene.16489

Andreas Moses Appel, Janet Janbek, Christina Jensen-Dahm, Thomas Munk Laursen, Gunhild Waldemar

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Abstract

Background and Purpose

Previous studies have reported conflicting results regarding the association between influenza vaccination and dementia. This association was investigated in a nationwide register-based cohort study.

Methods

Using nationwide registries, dementia-free adults aged ≥65 years in Denmark from 2002 to 2018 without previous influenza vaccinations were included. Poisson regression facilitated confounder-adjusted comparisons of dementia rates for ever versus never vaccinated, number of vaccinations and within/after 5 years from first vaccination. Sensitivity analyses included stratification on age and sex.

Results

Vaccination during follow-up was associated with a slightly higher rate of dementia when adjusted for sociodemographic factors and comorbidities, both within and after the first 5 years from first vaccination (incidence rate ratio [IRR] 1.04; 95% confidence interval [CI] 1.03–1.05). The rate of dementia decreased with increasing number of vaccinations. The highest rate was amongst those with only one vaccination (IRR 1.14; 95% CI 1.12–1.17) and the rate of dementia was only decreased amongst those with six or more vaccinations (IRR 0.95; 95% CI 0.93–0.97). Applying the same models to control outcomes of hip fracture and cancer resulted in higher rates amongst vaccinated people of 6% and 7%, respectively. Vaccinated people also had a 10% higher mortality rate.

Discussion

Our results do not support the case for a preventive effect of influenza vaccination on the risk of dementia in the general population, as reported by some previous studies. However, the higher dementia rate amongst vaccinated people found in this study is probably due to residual confounding, indicated by a higher rate for control outcomes and mortality.

Abstract Image

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接种流感疫苗对老年人痴呆症发病率的影响。

背景和目的：以往的研究报告显示，流感疫苗接种与痴呆症之间的关系存在相互矛盾的结果。我们在一项基于全国登记的队列研究中调查了这种关联：通过全国范围的登记，纳入了2002年至2018年期间丹麦年龄≥65岁且未曾接种过流感疫苗的无痴呆症成年人。泊松回归有助于对曾经接种与从未接种、接种次数以及首次接种后5年内/5年后的痴呆症发病率进行混杂因素调整后的比较。敏感性分析包括年龄和性别分层：结果：如果对社会人口学因素和合并症进行调整，在随访期间接种疫苗与痴呆症发病率略高有关，在首次接种疫苗后 5 年内和 5 年后均是如此（发病率比 [IRR] 1.04；95% 置信区间 [CI] 1.03-1.05）。痴呆症的发病率随着接种疫苗次数的增加而降低。仅接种过一次疫苗的人群痴呆率最高（IRR 1.14；95% CI 1.12-1.17），而接种过六次或六次以上疫苗的人群痴呆率仅有所下降（IRR 0.95；95% CI 0.93-0.97）。对髋部骨折和癌症的控制结果应用相同的模型，结果显示接种疫苗者的发病率分别高出 6% 和 7%。接种疫苗者的死亡率也高出 10%：讨论：我们的研究结果并不支持之前一些研究报告的流感疫苗接种对普通人群痴呆症风险有预防作用的观点。然而，本研究中发现的接种者痴呆症发病率较高可能是由于残余混杂因素造成的，对照结果和死亡率较高就说明了这一点。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

European Journal of Neurology 医学-临床神经学

CiteScore

9.70

自引率

2.00%

发文量

418

审稿时长

1 months

期刊介绍： The European Journal of Neurology is the official journal of the European Academy of Neurology and covers all areas of clinical and basic research in neurology, including pre-clinical research of immediate translational value for new potential treatments. Emphasis is placed on major diseases of large clinical and socio-economic importance (dementia, stroke, epilepsy, headache, multiple sclerosis, movement disorders, and infectious diseases).