***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: Abstract Background : Awareness and use of electronic cigarettes ( e-cigs ) has increased significantly in the past five years , but little is known about the experiences , satisfaction , opinions and preferences of  e-cigs users . Method : 1177 participants completed an online survey about their electronic cigarette preferences , of which 200 were r and omly selected for analysis . The data were analyzed using both qualitative and quantitative methods . Results : Participants found the design , the ability to customize , and the quality of vapour to be the most important characteristics of the device . Participants thought the most positive aspects of e-cig use were help to quit smoking , improved overall health , and reduced cost . The negative aspects associated with its use were mainly related to side effects , such as dry mouth . When asked to explain how e-cigs were used differently than cigarettes , participants reported puffing more regularly , but taking fewer puffs per session . Conclusions : Experienced e-cig users stated that initiating e-cig use helped them to quit or reduce their conventional smoking , which they believe reduced their health risks . In comparison to cigarette smoking , e-cig users reported using their e-cig more times per day , but with fewer puffs at each use time . Users acknowledged that more research is needed to underst and the safety and long-term effects of its use . They mentioned dry mouth as a common side effect and common problems with reliability of e-cigs . Underst and ing these views may help health professionals to assess and assist  e-cig users , and in the future , may help regulators to improve quality and reduce risks BACKGROUND Few national surveys document the prevalence of e-cigarette use in the U.S. The existing metric to assess current use likely identifies individuals who have recently tried an  e-cigarette  but do not continue to use the product . PURPOSE To document the prevalence of e-cigarette ever use , current use , and established use in a nationally representative survey of current and former cigarette smokers in the U.S. METHODS A r and om sample of current and former cigarette smokers completed a web-based survey in June 2013 ( n=2,136 ) . Data were analyzed in November 2013 . Multivariate logistic regression identified demographic and smoking-related factors associated with each use category . Point estimates with 95 % CIs described e-cigarette use behaviors ( e.g. , preferred br and , purchasing patterns ) for each group . RESULTS Almost half of respondents had tried e-cigarettes ( 46.8 % ) , but prevalence of established use remained low ( 3.8 % ) . Although trial of e-cigarettes was highest among daily smokers , the odds of being an established e-cigarette user were greater for former smokers ( OR=3.24 , 95 % CI=1.13 , 9.30 , p<0.05 ) . Furthermore , e-cigarette preference and use patterns varied among ever , current , and established users . Established users reported using rechargeable e-cigarettes  , having a regular br and , and using e-cigarettes at home and in the workplace at much higher levels than the " current use " metric captures . CONCLUSIONS Improved survey measures for e-cigarette use are needed . The identification of established e-cigarette users may provide insight to product features or other individual factors that are associated with sustained use of e-cigarettes Objectives : The objectives of this study were to assess the general public views and familiarity toward  electronic cigarette ( e-cigarette )  in Kuantan , Malaysia . Methodology : A total of 277 Kuantan people were involved in this study . The question naire was distributed at r and om in shops , businesses , and public places in Kuantan . Statistical analysis was performed using SPSS ( version 17.0 ) . Results : From 400 participants , a total number of 277 ( 160 , 57.7 % men and 117 , 42.4 % women ) respondents completed the question naire . The mean age was 26.89 ± 9.8 years old . The majority of the study participants were male ( 57.7 % ) , Malay ( 83.8 % ) , Muslims ( 83.8 % ) , singles ( 69 % ) , and employed ( 75.8 % ) , with about 83 ( 29.9 % ) of the respondents were smokers . The prevalence of e-cigarettes smokers was found to be only 1.4 % ( n = 4 ) . About one-third of the respondents ( n = 72 , 26 % ) have tried e-cigarette before . Job status was significantly associated with smoking e-cigarette among the population ( P = 0.02 ) . Main factors for a person to start e-cigarette smoking were curiosity ( 37.5 % ) and cheaper price ( 40.8 % ) . Majority of respondents agreed that e-cigarette would not affect health as normal cigarette , and that variety of flavors contribute to better enjoyment ( 51.6 % and 66.7 % , respectively ) . Conclusion : The results of the current study demonstrate that the prevalence of e-cigarettes smoking and its popularity , familiarity , and knowledge are still insufficient among Kuantan population . Further studies should be done to tackle this problem before it getting worse Aims : Here , we present results from a prospect i ve pilot study that was aim ed at surveying changes in daily cigarette consumption in smokers making their first purchase at vape shops . Modifications in products purchase were also noted . Design : Participants were instructed how to charge , fill , activate and use their e-cigarettes ( e-cigs ) . Participants were encouraged to use these products in the anticipation of reducing the number of cig/day smoked . Setting s : Staff from LIAF contacted 10 vape shops in the province of the city of Catania ( Italy ) that acted as sponsors to the 2013 No Tobacco Day . Participants : 71 adult smokers ( ≥18 years old ) making their first purchase at local participating vape shops were asked by professional retail staff to complete a form . Measurements : Their cigarette consumption was followed-up prospect ively at 6 and 12 months . Details of products purchase ( i.e. , e-cigs hardware , e-liquid nicotine strengths and flavours ) were also noted . Findings : Retention rate was elevated , with 69 % of participants attending their final follow-up visit . At 12 month , 40.8 % subjects could be classified as quitters , 25.4 % as reducers and 33.8 % as failures . Switching from st and ard refillables ( initial choice ) to more advanced devices ( MODs ) was observed in this study ( from 8.5 % at baseline to 18.4 % at 12 month ) as well as a trend in decreasing the e-liquid nicotine strength , with more participants adopting low nicotine strength ( from 49.3 % at baseline to 57.1 % at 12 month ) . Conclusions : We have found that smokers purchasing e-cigarettes from vape shops with professional advice and support can achieve high success rates PURPOSE Electronic cigarettes ( e-cigarettes ) are a new type of device that delivers vaporized nicotine without the tobacco combustion of regular cigarettes . We sought to underst and awareness of and willingness to try e-cigarettes among adolescent males , a group that is at risk for smoking initiation and may use e-cigarettes as a " gateway " to smoking . METHODS A national sample of 11 - 19-year-old males ( n = 228 ) completed an online survey in November 2011 . We recruited participants through their parents , who were members of a panel of U.S. households constructed using r and om-digit dialing and addressed-based sampling . RESULTS Only two participants ( < 1 % ) had previously tried e-cigarettes . Among those who had not tried e-cigarettes , most ( 67 % ) had heard of them . Awareness was higher among older and non-Hispanic adolescents . Nearly 1 in 5 ( 18 % ) participants were willing to try either a plain or flavored e-cigarette , but willingness to try plain versus flavored varieties did not differ . Smokers were more willing to try any e-cigarette than nonsmokers ( 74 % vs. 13 % ; OR 10.25 , 95 % CI 2.88 , 36.46 ) . Nonsmokers who had more negative beliefs about the typical smoker were less willing to try e-cigarettes ( OR .58 , 95 % CI .43 , .79 ) . CONCLUSIONS Most adolescent males were aware of  e-cigarettes  , and a substantial minority were willing to try them . Given that even experimentation with e-cigarettes could lead to nicotine dependence and subsequent use of other tobacco products , regulatory and behavioral interventions are needed to prevent " gateway " use by adolescent nonsmokers . Campaigns promoting negative images of smokers or FDA bans on sales to youth may help deter use Background More US adolescents use e-cigarettes than smoke cigarettes . Research suggests flavoured e-cigarettes appeal to youth , but little is known about perceptions of and reasons for attraction to specific flavours . Methods A national sample of adolescents ( n=1125 ) ages 13–17 participated in a phone survey from November 2014 to June 2015 . We r and omly assigned adolescents to respond to survey items about 1 of 5 e-cigarette flavours ( tobacco , alcohol , menthol , c and y or fruit ) and used regression analysis to examine the impact of flavour on interest in trying e-cigarettes and harm beliefs . Results Adolescents were more likely to report interest in trying an e-cigarette offered by a friend if it were flavoured like menthol ( OR=4.00 , 95 % CI 1.46 to 10.97 ) , c and y ( OR=4.53 , 95 % CI 1.67 to 12.31 ) or fruit ( OR=6.49 , 95 % CI 2.48 to 17.01 ) compared with tobacco . Adolescents believed that fruit-flavoured e-cigarettes were less harmful to health than tobacco-flavoured e-cigarettes ( p<0.05 ) . Perceived harm mediated the relationship between some flavours and interest in trying e-cigarettes . A minority of adolescents believed that e-cigarettes did not have nicotine ( 14.6 % ) or did not know whether they had nicotine ( 3.6 % ) ; these beliefs did not vary by flavour . Discussion C and y-flavoured , fruit-flavoured and menthol-flavoured e-cigarettes appeal to adolescents more than tobacco-flavoured or alcohol-flavoured e-cigarettes . This appeal is only partially explained by beliefs about reduced harm . Given adolescents ' interest in trying e-cigarettes with certain flavours , policymakers should consider restricting advertisements promoting flavoured products in media that reach large numbers of young people . Future research should examine other reasons for the appeal of individual flavours , such as novelty and perceived luxury INTRODUCTION This study examined overall changes in nicotine concentrations when using a popular e-cigarette and 18 mg/mL nicotine e-Juice , and it further explored effects of sex and flavorings on these concentrations . METHODS We recruited nontreatment-seeking smokers who were willing to try e-cigarettes for 2 weeks and abstain from cigarette smoking . Subjects were r and omized to either menthol tobacco or non-menthol tobacco-flavored e-cigarette use for 7 - 10 days , and the next week they were crossed over to the other condition . On the last day of e-cigarette use of each flavor , subjects completed a laboratory session in which they used the e-cigarette for 5 min ad libitum . Nicotine concentrations were obtained 5 min before and 5 , 10 , 15 , 20 , and 30 min after the onset of e-cigarette use . RESULTS Twenty subjects completed at least 1 monitoring session . Nicotine concentrations significantly increased from baseline to 5 min by 4 ng/mL at the first laboratory session ( p < .01 ) and by 5.1 ng/mL at the second laboratory session ( p < .01 ) . Combining sessions , there were no main effects of sex or preferred flavor ( based on smoking history ) on changes in nicotine concentrations . After adding preferred flavor , sex , and visit order to the model , there was a significant preferred flavor by sex interaction ( p < .01 ) , such that women who received nonpreferred flavors had lower nicotine concentrations and rated their e-cigarette as less likeable ( p < .01 ) . CONCLUSION We found nicotine concentrations significantly increase after e-cigarette use for 5 min , and flavor may impact nicotine concentrations with e-cigarette use in women AIMS To ( 1 ) estimate predictors of first- versus second-generation electronic cigarette ( e-cigarette ) choice ; and ( 2 ) determine whether a second-generation device was ( i ) superior for reducing urge to smoke and withdrawal symptoms ( WS ) and ( ii ) associated with enhanced positive subjective effects . DESIGN Mixed-effects experimental design . Phase 1 : reason for e-cigarette choice was assessed via question naire . Phase 2 : participants were allocated r and omly to first- or second-generation e-cigarette condition .  Urge to smoke and WS were measured before and 10 minutes after taking  
    Output:
    
Consumers preferred flavored e-cigarettes , and such preference varied with age groups and smoking status .
We also found that several flavors were associated with decreased harm perception while tobacco flavor was associated with increased harm perception .
In addition , some flavor chemicals and sweeteners used in e-cigarettes could be of toxicological concern .
Adolescents could consider flavor the most important factor trying e-cigarettes and were more likely to initiate vaping through flavored e-cigarettes .
Young adults overall preferred sweet , menthol , and cherry flavors , while non-smokers in particular preferred coffee and menthol flavors .
Adults in general also preferred sweet flavors ( though smokers like tobacco flavor the most ) and disliked flavors that elicit bitterness or harshness .
In terms of whether flavored e-cigarettes assisted quitting smoking , we found inconclusive evidence .
E-cigarette users likely initiated use with a cigarette like product and transitioned to an advanced system with more features .
Non-smokers and inexperienced e-cigarettes users tended to prefer no nicotine or low nicotine e-cigarettes while smokers and experienced e-cigarettes users preferred medium and high nicotine e-cigarettes .
Weak evidence exists regarding a positive interaction between menthol flavor and nicotine strength