Inflammation has been implicated in physical frailty, but its role in sensory impairment is unclear. Given that olfactory impairment predicts dementia and mortality, determining the role of the immune system in olfactory dysfunction would provide insights mechanisms of neurosensory decline. We analyzed data from the National Social Life, Health and Aging Project, a representative sample of home-dwelling older US adults. Plasma levels of 18 cytokines were measured using standard protocols (Luminex xMAP). Olfactory function was assessed with validated tools (n-butanol sensitivity and odor identification, each via Sniffin' Sticks). We tested the association between cytokine profiles and olfactory function using multivariate ordinal logistic regression, adjusting for age, gender, race/ethnicity, education level, cognitive function, smoking status, and comorbidity. Older adults with the IL-1Rahigh-IL-4low-IL-13low cytokine profile had worse n-butanol odor sensitivity (OR=1.61, 95% CI 1.19 - 2.17) and worse odor identification (OR=1.42, 95% CI 1.11 - 1.80). Proinflammatory, Th1 or Th2 cytokine profiles were not associated with olfactory function. Moreover, accounting for physical frailty did not alter the main findings. In conclusion, we identified a plasma cytokine signature - IL-1Rahigh - IL-4low - IL-13low - that is associated with olfactory dysfunction in older US adults. These data implicate systemic inflammation in age-related olfactory dysfunction and support a role for immune mechanisms in this process, a concept that warrants additional scrutiny.

中文翻译：

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IL-1Rahigh-IL-4low-IL-13low：一种与美国老年人嗅觉功能障碍相关的新型血浆细胞因子特征。


炎症与身体虚弱有关，但其在感觉障碍中的作用尚不清楚。鉴于嗅觉障碍可预测痴呆和死亡，确定免疫系统在嗅觉功能障碍中的作用将有助于深入了解神经感觉衰退的机制。我们分析了国家社会生活、健康和老龄化项目的数据，该项目是美国居家老年人的代表性样本。使用标准方案 (Luminex xMAP) 测量 18 种细胞因子的血浆水平。使用经过验证的工具（正丁醇敏感性和气味识别，均通过 Sniffin' Sticks）评估嗅觉功能。我们使用多变量序数逻辑回归测试了细胞因子谱与嗅觉功能之间的关联，并调整了年龄、性别、种族/民族、教育水平、认知功能、吸烟状况和合并症。 IL-1Rahigh-IL-4low-IL-13low 细胞因子谱的老年人对正丁醇气味敏感性较差（OR=1.61，95% CI 1.19 - 2.17），气味识别能力较差（OR=1.42，95% CI 1.11 - 1.80）。促炎、Th1 或 Th2 细胞因子谱与嗅觉功能无关。此外，考虑到身体虚弱并没有改变主要发现。总之，我们确定了与美国老年人嗅觉功能障碍相关的血浆细胞因子特征 - IL-1Rahigh - IL-4low - IL-13low。这些数据暗示了与年龄相关的嗅觉功能障碍中的全身炎症，并支持免疫机制在此过程中的作用，这一概念值得进一步审查。