Myrstad Christian, Engdahl Bo Lars, Costafreda Sergi Gonzales, Krokstad Steinar, Lin Frank, Livingston Gill, Strand Bjørn Heine, Øhre Beate, Selbæk Geir
The Norwegian National Centre for Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway.
Department of Medicine, Levanger Hospital, Nord-Trøndelag Hospital Trust, Levanger, Norway.
EClinicalMedicine. 2023 Dec 4;66:102319. doi: 10.1016/j.eclinm.2023.102319. eCollection 2023 Dec.
Hearing impairment is strongly associated with future dementia. No studies have reported objectively measured hearing impairment in a cohort with a long period of follow-up (>20 years), and few have reported follow-up over 10 years. Hence, there is a need for high quality studies with sufficient follow-up time and data to account for reverse causality and confounding. We aimed to address this knowledge gap.
This cohort study used individual participant data from The Trøndelag Health Study (HUNT) in Norway. All current residents aged at least 20 years in the former Norwegian Nord-Trøndelag County were invited to participate in four decennial surveys: HUNT1 (1984-1986), HUNT2 (1995-1997), HUNT3 (2006-2008), and HUNT4 (2017-2019) with individuals aged at least 70 years included in a substudy, known as HUNT4 70+. Here, we report the findings of this substudy. HUNT4 70+ comprised 7135 participants who were assessed for dementia using the Diagnostic and Statistical Manual of Mental Disorders 5 criteria and who had audiometry between 1996 and 1998. The primary objective was to investigate, with gold standard audiometric testing and dementia diagnostic assessment, whether hearing impairment was an independent risk factor for all-cause dementia. The secondary objective was to investigate if a risk also applied to Alzheimer dementia and non-Alzheimer dementia. We analysed the association using Poisson regression and adjusted for confounders. This study is registered with ClinicalTrials.gov (NCT04284384).
At baseline, 1058 (15%) individuals had acquired hearing impairment with a hearing threshold of at least 25 decibel (dB) and, at follow-up, 1089 (15%) had dementia. In the total group, people with hearing impairment had a relative risk (RR) 1.04 (95% confidence interval (CI) 1.00-1.09) per 10 dB increase in hearing thresholds. For individuals younger than 85 years at follow-up the RR was 1.12 (95% CI 1.05-1.21). Associations between hearing impairment and Alzheimer dementia and non-Alzheimer dementia were similar. There was no association for individuals aged at least 85 years.
We found a moderate association between objectively measured hearing impairment and dementia in the younger age group (<85 years). The findings of no association in the older age group (≥85 years) might be due to the competing risk of death. The present study adds to the literature showing that acquired hearing impairment is a risk for dementias over a period which is too long for reverse causation, and with thorough consideration of confounders. Further research is needed to investigate associations between the different aetiologies of hearing loss and dementia subtypes, and risk differences for sexes.
The Norwegian National Centre for Ageing and Health with a grant from Health South-East.
听力障碍与未来患痴呆症密切相关。尚无研究报告在长期随访（>20年）队列中客观测量的听力障碍情况，且很少有研究报告超过10年的随访情况。因此，需要高质量研究并具备足够的随访时间和数据，以解释反向因果关系和混杂因素。我们旨在填补这一知识空白。
这项队列研究使用了挪威特隆赫姆郡健康研究（HUNT）的个体参与者数据。挪威北特隆赫姆郡所有年龄至少20岁的现居居民受邀参加了四次十年期调查：HUNT1（1984 - 1986年）、HUNT2（1995 - 1997年）、HUNT3（2006 - 2008年）和HUNT4（2017 - 2019年），其中年龄至少70岁的个体纳入了一项子研究，即HUNT4 70 +。在此，我们报告这项子研究的结果。HUNT4 70 +包括7135名参与者，这些参与者使用《精神疾病诊断与统计手册》第5版标准进行痴呆症评估，并在1996年至1998年期间进行了听力测定。主要目标是通过金标准听力测试和痴呆症诊断评估，调查听力障碍是否是全因痴呆症的独立危险因素。次要目标是调查这种风险是否也适用于阿尔茨海默病性痴呆和非阿尔茨海默病性痴呆。我们使用泊松回归分析关联，并对混杂因素进行了调整。本研究已在ClinicalTrials.gov（NCT04284384）注册。
在基线时，1058名（15%）个体存在获得性听力障碍，听力阈值至少为25分贝（dB），随访时，1089名（15%）患有痴呆症。在整个组中，听力阈值每增加10 dB，听力障碍者的相对风险（RR）为1.04（95%置信区间（CI）1.00 - 1.09）。对于随访时年龄小于85岁的个体，RR为1.12（95% CI 1.05 - 1.21）。听力障碍与阿尔茨海默病性痴呆和非阿尔茨海默病性痴呆之间的关联相似。85岁及以上个体无关联。
我们发现，在较年轻年龄组（<85岁）中，客观测量的听力障碍与痴呆症之间存在中度关联。在较年长年龄组（≥85岁）中无关联的结果可能是由于死亡的竞争风险。本研究补充了相关文献，表明获得性听力障碍是痴呆症的一个危险因素，其影响时间之长排除了反向因果关系，且对混杂因素进行了全面考虑。需要进一步研究来调查听力损失的不同病因与痴呆症亚型之间的关联以及性别风险差异。
挪威国家老龄化与健康中心，由东南健康提供资助。
