Western Australian Centre for Health & Ageing, Centre for Medical Research, University of Western Australia, Crawley, Perth, WA, Australia.
Neuroimage. 2011 Apr 15;55(4):1480-9. doi: 10.1016/j.neuroimage.2011.01.063. Epub 2011 Jan 31.
Observational studies investigating the association between smoking, cognitive decline and dementia have produced conflicting results. We completed this trial to determine if smoking cessation decreases the progression of cognitive decline in later life.
We recruited older smokers (n=229) and never smokers (n=98) and invited smokers to join a smoking cessation trial. The primary outcome of interest was change in Alzheimer's Disease Assessment Scale cognitive subscale (ADAS-cog) scores over 24 months. Secondary measures included the Logical Memory test and changes in gray matter density. Successful smoking cessation was defined as a minimum of 547 smoking free days during follow up.
The ADAS-cog scores of unsuccessful quitters (UQ) increased (i.e., became worse) 1.1±0.3 and 1.2±0.4 points more than the scores of never smokers (NS) (p=0.001) and successful quitters (SQ) (p=0.006) respectively over the 24 months of follow up. Similarly, the scores of UQ declined (i.e., became worse) relative to NS on measures of immediate (p=0.004) and delayed recall (p=0.029). All analyses were adjusted for age, years of education, baseline cognitive performance, alcohol use, depression scores, and the presence of chronic respiratory disease. Thirty-six NS, 18 SQ and 48 UQ completed the imaging substudy. Compared with NS, UQ showed a disproportional loss of gray matter density in the right thalamus, right and left inferior semi-lunar lobule, as well as left superior and inferior parietal lobule over 24 months. SQ showed loss of gray matter compared with NS in the right middle and inferior occipital gyri, right and left culmen, and the left superior frontal gyrus. We did not find any brain regions in which UQ had lost more gray matter than SQ over 2 years.
These results are consistent with the hypothesis that smoking causes cognitive decline and loss of gray matter tissue in the brain over time.
观察性研究调查了吸烟、认知能力下降和痴呆之间的关系，结果相互矛盾。我们进行了这项试验，以确定戒烟是否能减缓老年人认知能力下降的进程。
我们招募了年龄较大的吸烟者（n=229）和从不吸烟者（n=98），并邀请吸烟者参加戒烟试验。主要观察指标是 24 个月内阿尔茨海默病评估量表认知子量表（ADAS-cog）评分的变化。次要指标包括逻辑记忆测试和灰质密度的变化。成功戒烟的定义是在随访期间至少有 547 天不吸烟。
不成功戒烟者（UQ）的 ADAS-cog 评分在 24 个月的随访中分别比从不吸烟者（NS）（p=0.001）和成功戒烟者（SQ）（p=0.006）多增加了 1.1±0.3 和 1.2±0.4 分。同样，UQ 在即时回忆（p=0.004）和延迟回忆（p=0.029）方面的得分也比 NS 下降（即变差）。所有分析均调整了年龄、受教育年限、基线认知表现、饮酒量、抑郁评分和慢性呼吸道疾病的存在。36 名 NS、18 名 SQ 和 48 名 UQ 完成了影像学子研究。与 NS 相比，UQ 在 24 个月内右丘脑、右和左下半月叶以及左顶上和下顶叶显示出不成比例的灰质密度丧失。与 NS 相比，SQ 在右中回和下枕叶、右和左鸡冠以及左额上回显示出灰质丧失。在 2 年内，我们没有发现 UQ 在任何脑区比 SQ 丧失更多的灰质。
这些结果与吸烟随时间导致认知能力下降和大脑灰质组织丧失的假设一致。
