Relation of Secondhand Smoking to Mild Cognitive Impairment in Older Inpatients

Abstract

Up to now, controversy still exists regarding the role of secondhand smoking (SHS) in developing cognitive impairment. This study aimed to evaluate the prevalence of SHS in hospitalized older patients with cognitive deficit, particularly in those with mild cognitive impairment (MCI). Smoking history was classified into four groups: never smokers, former-active smokers/no SHS, active smokers, and secondhand smokers, and cognitive function into three levels: normal cognition (C), MCI, and dementia. A total of 933 older subjects with diagnoses of MCI (n = 98), dementia (n = 124), or C (n = 711) were enrolled in this cross-sectional study. As expected, patients with dementia had significantly higher frequency of former-active smokers than cognitively normal. Moreover, patients with MCI showed a significantly higher frequency of active and secondhand smokers than patients with dementia or C. A smoking history is very frequent in older patients with dementia. Patients with MCI had even higher rate of exposure to active or secondhand smoking.

Passive Smoking Exposure in Living Environments Reduces Cognitive Function: A Prospective Cohort Study in Older Adults

“…Previous studies have shown that passive smoking can increase the risk of cognitive impairment or dementia, which is a possible outcome of cognitive impairment [14][15][16]. The results of our study also provided evidence of the harmful effect of passive smoking exposure on cognitive function.…”

Passive smoking as a risk factor for dementia and cognitive impairment: systematic review of observational studies

“…Nine papers were included in the final analysis, four of which reported research conducted in China (Chen, 2012 ; Chen et al , 2012 ; 2013a ; 2013b ), two in the UK (Llewellyn et al , 2009 ; Heffernan and O'Neill, 2013 ), two in the USA (Barnes et al , 2010 ; Akhtar et al , 2013 ), and one in Italy (Orsitto et al , 2012 ). They comprised seven cross-sectional studies, one between-groups design, and one longitudinal study.…”

“…All studies included standard cognitive tests and justified their use. Three studies also included clinical interview to verify diagnoses of dementia or the presence of cognitive impairment (Barnes et al , 2010 ; Chen, 2012 ; Orsitto et al , 2012 ). One paper included both a standardized test and self-reported functional limitation from memory impairment (Akhtar et al , 2013 ).…”

“…One paper included both a standardized test and self-reported functional limitation from memory impairment (Akhtar et al , 2013 ). Four studies (Barnes et al , 2010 ; Chen, 2012 ; Chen et al , 2012 ; 2013b ) referred to dementia as a measured outcome, one included both dementia and Mild Cognitive Impairment (Orsitto et al , 2012 ), another three focused on general cognitive impairment (Llewellyn et al , 2009 ; Akhtar et al , 2013 ; Chen et al , 2013a ), and one paper specifically examined prospective memory (Heffernan and O'Neill, 2013 ).…”

“…Six papers reported an association between increased levels of passive smoking and a form of cognitive impairment (Llewellyn et al , 2009 ; Chen et al , 2012 ; Orsitto et al , 2012 ; Akhtar et al , 2013 ; Chen et al , 2013a ; Heffernan and O'Neill, 2013 ). Two papers described an association between passive smoking and dementia (Chen, 2012 ; 2013b ).…”