Middle-aged adults who smoke tended to perform poorly on tests of memory and reasoning compared to nonsmokers, adding to the list of reasons not to smoke, French researchers said on Monday.
Analyzing previously collected data on about 5,000 British civil servants, the researchers found those who smoked were more likely than people who never smoked to be in the lowest-performing of five groups in tests of memory, reasoning, vocabulary and verbal fluency.
Smoking was associated with mental decline in middle age, as it is with dementia and a host of physical ills later in life, they found.
"Smoking in middle age is associated with memory deficit and decline in reasoning abilities," concluded Severine Sabia and colleagues from the National Institute of Health and Medical Research in Villejuif, France.
Compared to smokers, people who said they had quit cigarettes were more likely to adopt healthier behaviors, such as drinking less alcohol, being more physically active, and eating more fruits and vegetables, Sabia reported in the journal Archives of Internal Medicine.
The participants were aged 35 to 55 at the beginning of the study, which followed some subjects up to 17 years.
The study also demonstrated how difficult it can be to conduct long-term research on smokers: more than twice as many smokers as non-smokers refused to take the memory test again or were not able to be re-tested, in some cases because they died in the interim.
法国研究人员于本周一称，与不吸烟者相比，中年吸烟者在记忆力和推理测试中的表现较差。这无疑是戒烟的又一个理由。
研究人员分析了之前收集的英国约五千名公务员的有关数据后发现，与从不吸烟者相比，吸烟者在记忆力、推理、词汇和口头表达等几项测试中表现居五组中最差的几率更大。
研究人员发现，吸烟会导致中年人智力水平下降，而且会导致日后老年痴呆及其它很多身体性疾病。
位于法国维勒瑞夫的全国健康与医疗研究所的瑟弗琳?萨比娅及其同事得出结论：“中年吸烟会导致记忆力减退和推理能力下降。”
萨比娅在发表于《内科医学档案》期刊上的研究报告中称，与吸烟者相比，称自己已戒烟的人更易养成更为健康的生活习惯，比如少喝酒、多锻炼，多吃水果和蔬菜。
这项研究刚开始时，研究对象的年龄在35岁至55岁之间，研究人员对其中一些人进行了长达17年的跟踪调查。
该研究还让人们了解到对吸烟者进行长期的跟踪调查有多么困难：拒绝再次接受记忆测试或者无法再次接受测试的吸烟者比不吸烟者多一倍以上，有些是因为研究对象在此期间已去世。
