Geriatrics Division, Department of Medicine, Howard University, 2041 Georgia Ave NW, Washington, DC 20060, USA.
Int J Environ Res Public Health. 2011 Sep;8(9):3628-36. doi: 10.3390/ijerph8093628. Epub 2011 Sep 7.
Previous studies report that low levels cognitive function and history of smoking are associated with increased mortality risk. Elderly smokers may have increased risk of dementia, but risk in former smokers is unclear. We tested the hypotheses that the harmful effect of impaired cognitive function as related to mortality is greater in persons smoking at baseline than in others. Further, we used serum cotinine levels to assess recall bias of smoking history by cognitive function level. Data were analyzed from a longitudinal mortality follow-up study of 4,916 American men and women aged 60 years and over, examined in 1988-1994 with complete data followed an average 8.5 years. Measurements at baseline included smoking history, a short index of cognitive function (SICF), serum cotinine and socio-demographics. Death during follow-up occurred in 1,919 persons. In proportional hazards regression analysis, a significant interaction of current smoking with cognitive function was not found; but there was a significant age-smoking interaction. After adjusting for confounding by age or multiple variables, current smoking associated with over 2-fold increased mortality (hazards ratio and 95% confidence limits current versus never smoking 2.13, 1.75-2.59) and SICF with 32% reduction in mortality; top versus bottom SICF stratum 0.68, 0.53-0.88). Serum cotinine data revealed substantial recall bias of smoking history in persons with cognitive impairment. However analyses correcting for this bias did not alter the main conclusions: In a nationwide cohort of older Americans, analyses demonstrated a lower risk of death independent of confounders among those with high SICF scores and never smokers, without a significant interaction of the two.
先前的研究报告指出，认知功能低下和吸烟史与死亡率升高有关。老年吸烟者可能有更高的痴呆风险，但以前吸烟者的风险尚不清楚。我们检验了这样一个假设，即认知功能受损与死亡率相关的有害影响在基线时吸烟的人比其他人更大。此外，我们使用血清可替宁水平来评估认知功能水平与吸烟史回忆偏倚的关系。这项数据来自一项对 4916 名年龄在 60 岁及以上的美国男女进行的纵向死亡率随访研究，这些人于 1988-1994 年接受检查，平均随访 8.5 年，数据完整。基线测量包括吸烟史、认知功能简短指数（SICF）、血清可替宁和社会人口统计学。随访期间有 1919 人死亡。在比例风险回归分析中，未发现当前吸烟与认知功能之间存在显著的交互作用；但存在显著的年龄-吸烟交互作用。在调整年龄或多个变量的混杂因素后，当前吸烟与死亡率增加两倍以上相关（风险比和 95%置信区间当前与从不吸烟为 2.13，1.75-2.59），SICF 与死亡率降低 32%相关；最高与最低 SICF 分层为 0.68，0.53-0.88）。血清可替宁数据显示，认知障碍者的吸烟史存在大量回忆偏倚。然而，校正这种偏倚的分析并没有改变主要结论：在一个全国性的美国老年人队列中，分析表明，无论混杂因素如何，SICF 评分高且从不吸烟的人死亡风险较低，两者之间没有显著的相互作用。
