Author's response to reviews Title:Prevalence of binge drinking and associated behaviours among 3286 college students in France Authors: Marie-Pierre Tavolacci (marie-pierre.tavolacci@chu-rouen.fr) Eloise Boerg (eboerg@yahoo.fr) Laure Richard (laureanne.richard@gmail.com) Gilles Meyrignac (gilles.meyrignac@univ-rouen.fr) Pierre Dechelotte (pierre.dechelotte@chu-rouen.fr) Joel Ladner (joel.ladner@chu-rouen.fr) Version:3Date:7 January 2016 Author's response to reviews: see over
Reviewer's report Title:Prevalence of binge drinking and associated behaviours among 3286 college students in France Version:2Date:19 September 2015 Reviewer:Johan Svensson Reviewer's report: Comments to Prevalence of binge drinking and associated substance use among college students in France, BMC Public Health, submitted 2015-06-24 Introduction The aim of this study is to assess the prevalence of binge drinking and associated behaviours among college students in upper Normandy, France. The analysis is based on data collected between November 2009 and February 2013. A total of app. 3200 students were included in the sample and the analysis is made by logistic regression models. The results indicate that frequent BD had a positive associated to males, living in rented accommodations, business school, regular practice of sports and smoking and occasional cannabis use. Occasional BD had almost the same association. A negative association was found between frequent BD and grant holder status, living in couples and stress. This paper contributes to the literature since the data are from France which is surprisingly rare. However, the paper is in need of improvements and clarifications. Author s response to review: see below Major compulsory revisions 1, A general remark is that the text needs further improvements when it comes to language! According to the reviewer s suggestion, the manuscript has been thoroughly checked once again by a native English speaker in terms of grammar, spelling and in order to enhance the overall level of language. 2, In the abstract (line 25) there is no background only an aim! Please ad some sentence as a background! As requested by the reviewer, we have added a background in the abstract: "Studies conducted on characteristics of binge drinking and associated behaviours in college student populations are scarce especially in France. Hence, it is important to identify risk factors for binge drinking at university, especially those which may be changed. " 3, The authors acknowledge the fact that the sample is not random (line 336) and argument (following lines) does not make it more randomised or more representative! Instead I would like to see if the trend of BD are similar compared to other regions of France or the whole of France, in the same age groups or similar age groups. The point being, is this a typical or atypical region of France? Is it reasonable to assume
that the found associations are similar elsewhere? Furthermore, it is stated that students were invited... (line 119), how many were invited? Possible selection effects are not discussed in the context of the findings. Is it possible that those who drink a lot were more prone to participate in the study? According a national study, the prevalence of monthly binge drinking and yearly binge drinking among 18 to 24 year-olds in France, was respectively 28% and 52%. Comparisons seem to be difficult because of frequencies assessment that are not the same as our study. "The main characteristics of our sample are no different to those of a European study on 36000 French students (Hauschildt et al 2015). Our study population was two thirds women and one third men (in the European study there were 63% women and 37% men). The mean age in our sample was 20.5 years compared to 21.2 years in the European study. The National Institute for Prevention and Education in Healthcare (INPES) survey conducted in 2010 reported that 23.2% of college students were smokers, a figure similar to ours. So even if ours was a convenience sample, these characteristics do not seem to be different to those of other French university students and might be considered as representative of the student population". We have clarified the fact that study participation was by invitation: "Students were invited to take part in our cross sectional study during health forums on campus, by email, or during their mandatory medical survey at the university medical department. The students filled out a confidential self-administered questionnaire on the TS1C website or a paper questionnaire." "Self-reported substance use has, however, been shown to be reliable for the substances studied. " 4, Another problem with the data is that the data have been collected for more than 3 years but analysed as cross sectional. The author s needs to address the fact that the associations found may be a result for one year or one semester only. To address this I would like to see some analyses over time, comparing for instance the proportion of BD over time. These analyses do not need to be presented in a table. A paragraph in the Data and Methods segment would be sufficient to settle these suspicions. Furthermore, when it comes to the data being collected over time it would also be interesting so see if trends in BD follows the trend of an academic year. I do not know if this is the case in France, but usually there are periods of exams or periods of more intense work and do these periods coincide with low rates of BD in the data? As requested by the reviewer, we have analysed frequence of binge drinking by year of data collection Never (%) Occasional BD (%) Frequent BD (%) November 2009-2010 26.2 54.1 19.7 2011 39.7 50.9 9.4 2012-February 2013 40.8 49.7 9.5
Total 34.9 51.3 13.8 In 2010, three quarters of business school students were included which could explain the high frequency of frequent BD during this year, in fact this particular curriculum showed a high risk of frequent BD (ORa=4.72) There was no difference between 2011 and 2012-February 2013. It is difficult to compare periods of the academic year since exams are held at different times and with different frequencies according to curricula. As reported in the table 1, the academic year of study of students (1,2, 3 or more than 3) was analysed as a risk factors no difference was found according to year of study (p=0.31). 5, I also lack a specific aim with the study! Yes, there is an aim in the abstract but not in the text. The paper appears to be very data driven with no clear and stated research questions. Please include! We thank the reviewer for this pertinent remark and accordingly the objectives of the study are now clearly stated as follows "The aim of this present study was to assess the prevalence of binge drinking and associated behaviours across a large sample of college students in France." 6, From what I can see figure 1 (or to be precise it does not have a number) is not discussed either delete or discuss! As there is only one figure, it is not numbered. The figure is discussed in the results section: "Frequent BD was significantly more common in male students (24.6%) than in female students (7.4%); and never BD was more common in female students (40.7%) than in male students (22.6%) (p<0.0001) (figure)." 7, Table 1 and table 2 are unclear! If I understand them correct they are a mixture of descriptive of the data and the logistic regression? I suggest you make one descriptive table only, with the left columns in table 1 and 2 in one table and another table including the logistic regression only. As suggested by the reviewer table 1 and table 2 have been modified. Table 1 now shows a description of baseline characteristics and the behaviour risks of the population. Table 2 only shows results after logistic regression. 8, From table 1, it appears like the proportion of frequent BD are decreasing with the number of years in academia, from 45.5(%) in year 1 to 17.3 in year 3 and 20.5 in year >3 years. If this is the case why isn t these data included in the analysis (in the log reg model)??? The data in table 1 is presented by column (the total per column is 100%). This table does not show the prevalence of BD according to year but rather indicates the distribution of students by year according to the frequency of BD (occasional and frequent). Among frequent binge drinkers, 45.5% are in year 1, 16.7% in year 2, and 17.3% in year 3 and 20.5 % in year>3. Minor revisions: 9. When describing the measurements, please indicate the time frame of the specific measurements. For instance when it comes to binge drinking (line 151) is the
frequency asked for during the past 12 months? This is expressed when it comes to cannabis use (line 177), sleeping (line 202). When it comes to sleeping, there is a gap between this measurement and cannabis use sleeping during the last week and cannabis use during the past 12 months which needs to be addressed and discussed! More importantly this goes for BD as well - I suspect (but do not know since the time frame is not stated)! In answer to the reviewer s question regarding the time frame for the assessment of BD, we have added the phrase during the past 12 months.. For cannabis use and sleeping which were categorized according the period of measurement of standardized definition. 10, In the discussion segment (line 292), please discuss why there may be a discrepancy between the findings in this study and the ones referred to (Bartoli et al.). Our results are similar to those of Bartoli: our grant holder students had a lower risk of BD because these students probably do not have much money available to buy alcohol. Indeed as shown by Bartoli, available money is a factor for BD: young adults with large amounts of money to spend at the weekend were more prone to BD. Level of interest:an article whose findings are important to those with closely related research interests Quality of written English:Needs some language corrections before being published Statistical review:no, the manuscript does not need to be seen by a statistician. Declaration of competing interests: I declare that I have no competing interests