Table_1_Sex differences in olfactory cortex neuronal loss in aging.docx

IntroductionAging plays a major role in neurodegenerative disorders such as Alzheimer’s disease, and impacts neuronal loss. Olfactory dysfunction can be an early alteration heralding the presence of a neurodegenerative disorder in aging. Studying alterations in olfaction-related brain regions might help detection of neurodegenerative diseases at an earlier stage as well as protect individuals from any danger caused by loss of sense of smell.ObjectiveTo assess the effect of age and sex on olfactory cortex volume in cognitively healthy participants.MethodNeurologically healthy participants were divided in three groups based on their age: young (20–35 years; n = 53), middle-aged (36–65 years; n = 66) and older (66–85 years; n = 95). T1-weighted MRI scans acquired at 1.5 T were processed using SPM12. Smoothed images were used to extract the volume of olfactory cortex regions.ResultsANCOVA analyses showed significant differences in volume between age groups in the olfactory cortex (p ≤ 0.0001). In women, neuronal loss started earlier than in men (in the 4th decade of life), while in men more substantial neuronal loss in olfactory cortex regions was detected only later in life.ConclusionData indicate that age-related reduction in the volume of the olfactory cortex starts earlier in women than in men. The findings suggest that volume changes in olfaction-related brain regions in the aging population deserve further attention as potential proxies of increased risk of neurodegenerative diseases.

引言老化在诸如阿尔茨海默病等神经退行性疾病的发生中扮演着至关重要的角色，并对神经元损失产生显著影响。嗅觉功能障碍可能成为预示神经退行性疾病早期存在的先兆，特别是在老龄化进程中。研究嗅觉相关脑区的变化，有助于在疾病早期阶段对其进行检测，并保护个体免受嗅觉丧失带来的潜在危险。目标评估年龄和性别对认知健康个体嗅觉皮层体积的影响。方法基于受试者的年龄，将神经学健康的参与者分为三组：青年组（20-35岁；n=53）、中年组（36-65岁；n=66）和老年组（66-85岁；n=95）。使用1.5T的T1加权MRI扫描，并通过SPM12进行处理。使用平滑后的图像提取嗅觉皮层区域的体积。结果通过方差分析（ANCOVA）表明，在嗅觉皮层中，不同年龄组之间体积存在显著差异（p ≤ 0.0001）。在女性中，神经元损失开始得比男性早（在生命中的第四十年），而在男性中，嗅觉皮层区域的神经元损失更为显著，且出现在晚年。结论数据表明，与男性相比，女性嗅觉皮层体积的年龄相关性减少开始得更早。研究结果提示，在老龄化人群中，嗅觉相关脑区的体积变化值得进一步关注，因其可能作为神经退行性疾病风险增加的潜在指标。