Olfactory impairments may provide early indications of future health outcomes in older adults. Thus, an important question concerns whether these impairments can be self-assessed. Previous findings of cross-sectional studies indicate low correlations between self-reported olfactory function and objective olfactory performance. On the other hand, subjective olfactory impairments predict future dementia and mortality in longitudinal settings. No previous study has assessed the relationship between subjectively and objectively measured decline in olfaction over time. Based on data for 903 older adults derived from the Betula Study, a Swedish population-based prospective study, we tested whether rate-of-change in odor identification could be predicted from subjective olfactory decline over a time span of 10 years during which subjective and objective odor functions were assessed on 2 or 3 test occasions. Indeed, we found that participants who experienced subjective olfactory decline over the study period also had significantly steeper rates of decline in odor identification, even after adjusting for demographic, cognitive, and genetic factors that previously have been associated with performance in odor identification. This association was, however, not present in a subsample with baseline cognitive impairment. We interpret these results as evidence that when asked about whether they have an olfactory impairment or not, older persons are assessing intraindividual olfactory changes, rather than interindividual differences. Our results indicate that subjective olfactory loss reflects objective olfactory decline in cognitively intact older adults. This association might be harnessed to predict health outcomes and highlights the need to develop effective olfactory self-assessments.

中文翻译：

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老年人的主观嗅觉丧失与长期气味识别下降相一致。

嗅觉障碍可能为老年人将来的健康状况提供早期迹象。因此，一个重要的问题涉及这些损伤是否可以自我评估。横截面研究的先前发现表明，自我报告的嗅觉功能与客观嗅觉表现之间的相关性较低。另一方面，主观嗅觉障碍可预测纵向环境中未来的痴呆症和死亡率。以前没有研究评估主观和客观测量的嗅觉随时间下降之间的关系。根据Betula研究（瑞典一项基于人口的前瞻性研究）获得的903位老年人的数据，我们测试了是否可以通过在10年内主观嗅觉下降来预测气味识别的变化率，在此过程中，在2或3个测试场合中评估了主观和客观的气味功能。确实，我们发现在研究期间经历了主观嗅觉下降的参与者，即使在调整了先前与气味识别性能相关的人口统计学，认知和遗传因素之后，气味识别的下降率也明显更高。但是，在基线认知障碍的子样本中不存在这种关联。我们将这些结果解释为证据，当被问及老年人是否患有嗅觉障碍时，老年人正在评估个人的嗅觉变化，而不是个体差异。我们的结果表明，主观嗅觉丧失反映了认知完整的成年人的客观嗅觉下降。可以利用这种关联来预测健康结果，并强调需要进行有效的嗅觉自我评估。