***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: INTRODUCTION There is growing evidence that the mailed distribution of free nicotine replacement therapy ( NRT ) , usually as part of smokers ' helplines , can been effective in increasing the odds of cessation on a population level . However , limited information is available on the utilization of NRT when it is provided for free , and factors associated with regimen adherence have remained largely unexplored . METHODS In the context of a r and omized controlled trial , 500 adult smokers across Canada hypothetically interested in free NRT  were mailed a 5week supply of nicotine patches , but no other support was offered . Analyses evaluated which a priori-defined demographic and smoking characteristics predicted  nicotine patch use at 8week follow-up of 421 patch recipients , as well as examined the association between patch use and smoking cessation at 6months . RESULTS At 8weeks , 10.9 % had used all , 47.5 % had used some but not all , and 41.6 % had not used any of the provided nicotine patches . Lower age , unemployment , past NRT use and intent to quit in the next 30days at baseline ( preparation stage of change ) were all identified as independent predictors of some nicotine patch use . Only use of all patches was associated with greater odds of smoking cessation , compared to non-users ( Adj . OR=2.96 ; 95%CI=1.06 - 8.27 ) . CONCLUSIONS The mailed distribution of free nicotine patches to smokers at large can be effective at promoting cessation , particularly among financially disadvantaged groups , those with previous NRT experience and among individuals with already advanced intent to quit AIMS To propose a hierarchy of method ological criteria to consider when determining whether a study provides sufficient information to answer the question of whether e-cigarettes can facilitate cigarette smoking cessation or reduction . DESIGN A PubMed search to 1 February 2017 was conducted of all studies related to e-cigarettes and smoking cessation or reduction . SETTING S Australia , Europe , Iran , Korea , New Zeal and and the United States . PARTICIPANTS AND STUDIES 91 articles . MEASUREMENTS Coders organized studies according to six proposed method ological criteria : ( 1 ) examines outcome of interest ( cigarette abstinence or reduction ) , ( 2 ) assesses e-cigarette use for cessation as exposure of interest , ( 3 ) employs appropriate control/comparison groups , ( 4 ) ensures that measurement of exposure precedes the outcome , ( 5 ) evaluates dose and duration of the exposure and ( 6 ) evaluates the type and quality of the e-cigarette used . FINDINGS Twenty-four papers did not examine the outcomes of interest . Forty did not assess the specific reason for e-cigarette use as an exposure of interest . Twenty papers did not employ prospect i ve study design s with appropriate comparison groups . The few observational studies meeting some of the criteria ( duration , type , use for cessation ) triangulated with findings from three r and omized trials to suggest that e-cigarettes can help  adult smokers quit or reduce cigarette smoking . CONCLUSIONS Only a small proportion of studies seeking to address the effect of  e-cigarettes  on smoking cessation or reduction meet a set of proposed quality st and ards . Those that do are consistent with r and omized controlled trial evidence in suggesting that e-cigarettes can help with smoking cessation or reduction 
    Output:
    
We found mixed patterns of  e-cigarette current use by SES , with evidence of higher use among low-income adults but unclear or mixed findings by education and occupation .
In contrast , smokeless tobacco current use was consistently higher among low SES adults .
There was very limited evidence on the SES distribution of NRT in adults and of all NCNPs in young people .
The only NCNP for which there are clear patterns of use by SES is smokeless tobacco , where prevalence is higher among low SES groups .
While this suggests a potentially positive impact on inequalities in smoking ( if NCNP use displaces smoked tobacco use ) , this has not been seen in practice .
These findings do not support the suggestion that e-cigarettes have the potential to reduce social inequalities in smoking , since i ) current evidence does not show a clear trend of higher  e-cigarette use in population groups with higher tobacco consumption , and ii ) the experience of smokeless tobacco suggests that – even where NCNP use is higher among low SES groups – this does not necessarily replace smoked tobacco use in these groups