2型糖尿病患者嗅觉功能与认知功能关系的随访研究

Relationship between olfaction and cognitive function in patients with type 2 diabetes mellitus:a follow-up study

目的探讨纵向随访的2型糖尿病(T2DM)患者认知功能变化特点及基线嗅觉功能与糖尿病认知功能变化的关系。方法为前瞻性研究。纳入自2016年1月至2022年1月于鼓楼医院内分泌科住院的基线认知功能正常且有完整基线及随访资料的T2DM患者。基线时进行嗅觉行为学测试,随访前后均进行全套认知功能评估,认知功能评分变化值定义为随访认知得分减基线认知得分,正值表示上升,负值表示下降。按基线嗅觉测试总分三分位数将研究对象分为低分位组(<45.0分)、中分位组(45.0~49.4分)和高分位组(≥49.5分)3组。采用配对t检验比较随访及基线临床指标及认知功能。采用偏相关分析法分析嗅觉测试得分与认知评分变化之间的相关性。采用单因素方差分析比较3组认知评分变化。结果35例患者完成随访,基线年龄(56.4±7.9)岁,中位随访时间4.6年。与基线相比,随访后T2DM患者的记忆功能评分和语义流畅性明显下降[分别为(167.3±22.8)和(144.8±18.6)分,(22.1±4.4)和(19.1±4.8)分,均P<0.01],其中65.7%(23/35)的患者记忆功能评分下降,37.2%(13/35)语义流畅性下降。校正基线年龄、性别、受教育年限、糖尿病病程、糖化血红蛋白、随访时长后进行偏相关分析,基线嗅觉测试总分与记忆功能评分变化值显著相关(r=0.400,P<0.05)。低分位组11例、中分位组12例、高分位组12例。与高分位组相比,低分位组患者的记忆功能评分下降明显(P<0.05)。结论嗅觉测试总分低的认知功能正常的T2DM患者,随访后的记忆功能评分下降显著,嗅觉功能受损可以作为T2DM患者记忆功能下降的早期预测指标。

Objective To investigate the evolution of cognitive function and its relationship with olfaction in patients with type 2 diabetes mellitus(T2DM)who were longitudinally followed up.Methods The prospective study included T2DM patients with complete baseline and follow-up data who were hospitalized in the Endocrinology Department of Drum Tower Hospital from January 2016 to January 2022.Smell behavior tests were performed at baseline,and elaborate cognitive assessment were performed both at baseline and follow-up.The change value of cognitive function was defined as follow-up cognitive scores minus baseline cognitive scores,positive scores indicated increase and negative scores indicated decrease.Paired t-test was used to compare clinical indicators and cognitive test scores before and after the follow-up.Partial correlation was used to analyze the correlation between olfactory test scores and changes in cognitive domains.Participants were categorized into low-smell score group(<45.0 points),middle-smell score group(45.0-49.4 points)and high-smell score group(≥49.5 points)by tertile based on the total smell test scores at baseline,and the cognitive test scores of the three groups were compared by one-way analysis of variance(ANOVA).Results Thirty-five T2DM patients completed the follow-up,the baseline age was(56.4±7.9)years,and the median follow-up time was 4.6 years.Compared with baseline,patients with T2DM showed statistically significant decrements in memory and verbal fluency at follow-up[(167.3±22.8)vs.(144.8±18.6)points,P<0.01;(22.1±4.4)vs.(19.1±4.8)points,P<0.01,respectively].Memory and verbal fluency descent were separately found in 65.7%(23/35)and 37.2%(13/35)of the patients.Partial correlation analysis was performed after adjusting for baseline age,gender,years of education,duration of diabetes,glycated hemoglobin A1c,and time of follow-up.The significant association of the changes in memory with the total scores of the smell test at baseline was observed(r=0.400,P<0.05).There were separately 11,12,12 participants in the low-,middle-and high-smell scores group.Compared with patients in the high-smell scores group,patients with low-smell scores had greater memory decline(P<0.05).Conclusions After a median follow-up of 4.6 years,the memory and verbal fluency of T2DM patients significantly decreased.Patients with lower olfactory test scores had greater memory decline.Olfactory impairment might be a potential marker of memory decline in T2DM patients.