Heavy episodic drinking and alcohol-related injuries: An open cohort study among college students

HEAVY EPISODIC DRINKING AND ALCOHOL-RELATED INJURIES: AN OPEN COHORT STUDY AMONG COLLEGE STUDENTS. Authors: Francisco Caamaño-Isorna, Lucía Moure-Rodríguez, Sonia Doallo , Montserrat Corral, Socorro Rodriguez Holguín, Fernando Cadaveira This is the peer reviewed version of the following article: Caamaño-Isorna F; Moure-Rodríguez L; Doallo S; Corral M;, Rodriguez Holguín S; Cadaveira F (2017). Heavy episodic drinking and alcohol-related injuries: an open cohort study among college students. Accident Analysis & Prevention, 100, 23-29. doi: 10.1016/j.aap.2016.12.012 0001-4575. This article may be used for non-commercial purposes in accordance with Elsevier Terms and Conditions for Use of SelfArchived Versions Running head: HEAVY EPISODIC DRINKING & ALCOHOL-RELATED INJURIES 1 Heavy episodic drinking and alcohol-related injuries: An open cohort study 1 among college students. 2 3 Authors: Francisco Caamaño-Isornaa, Lucía Moure-Rodrígueza, Sonia Doallob, Montserrat 4 Corralb, Socorro Rodriguez Holguínb, Fernando Cadaveirab. 5 6 a CIBER de Epidemiología y Salud Pública (CIBERESP). Department of Public Health. 7 Universidade de Santiago de Compostela. Santiago de Compostela. Spain. 8 b Department of Clinical Psychology and Psychobiology. Universidade de Santiago de 9 Compostela. Santiago de Compostela. Spain 10 11 Corresponding author: 12 Lucía Moure-Rodríguez. 13 Department of Public Health. Universidade de Santiago de Compostela. 14 15784 Santiago de Compostela. Spain 15 [email protected] 16 17 18 19 20 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 2 Abstract 21 Aim: The objective of this study is to assess the effects of Heavy Episodic Drinking (HED) 22 on the incidence of alcohol-related injuries among university students in Spain, taking sex 23 into consideration. 24 Methods: We carried out an open cohort study among college students in Spain (992 women 25 and 371 men). HED and alcohol-related injuries were measured by question 3th and 9th of 26 Alcohol Use Disorders Identification Test to every participant at the ages of 18, 20, 22, 24 27 and 27. For data analysis we used a Multilevel Logistic Regression for repeated measures 28 adjusting for alcohol and cannabis use. 29 Results: The incidence rate of alcohol-related injuries was 0.028 year-1 for females and 0.036 30 year-1 for males. The multivariate analysis showed that among females a high frequency of 31 HED and use of cannabis are risk factors for alcohol-related injuries (Odds Ratio [OR]=2.64 32 and OR=3.68), while being more than 23 is a protective factor (OR=0.34). For males, 33 bivariate analysis also showed HED like risk factor (OR=4.69 and OR=2.51). Finally, the 34 population attributable fraction for HED among females was 37.12%. 35 Conclusions: HED leads to an increase of alcohol-related injuries in both sexes and being 36 over 23 years old acts as a protective factor among women. Our results suggest that about one 37 third of alcohol-related injuries among women could be avoided by removing HED. 38 Key words: youth, alcohol, cohort study, injury, heavy episodic drinking. 39 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 3 1. Introduction 40 Risk behavior, including substance use, is common among youth.[Pickett et al., 2002] 41 Specifically, rates of heavy episodic drinking (HED) behavior are increasing among young 42 people around the world.[Jernigan, 2001] This alcohol consumption pattern is characterized 43 by the intake of large amounts of alcohol in a short period of time, reaching blood alcohol 44 concentrations of 0.8g/l or greater.[National Institute on Alcohol Abuse and Alcoholism, 45 2016] Reich´s research found that about 58% of youth between 22 and 23 years old practice 46 HED. This proportion decreased after 5 years, among the same participants, to 42%.[Reich et 47 al., 2015] Spain is no exception, with high rates of HED. The prevalence of HED in Spain 48 among youth from 14 to 18 years old is 41.8%.[Delegación del Gobierno para el Plan 49 Nacional sobre Drogas, 2013] 50 During the college years people acquire behavior patterns and life styles that they maintain 51 through adulthood.[Schulenberg et al., 1996] Excessive alcohol consumption during youth is 52 also associated with an increased risk of dependence and alcohol-related problems in 53 adulthood.[Grant et al., 2006] Importantly, cerebral maturity, specifically in frontal and 54 temporal regions, continue to develop during adolescence and youth. These regions are also 55 particularly susceptible to the effects of alcohol.[Guerri and Pascual, 2010] Other 56 consequences that have been associated with HED are lower academic achievement,[Mota et 57 al., 2010; Powell et al., 2004] unsafe sex [Cooper, 2002; Moure-Rodríguez et al.,2016] and car 58 accidents.[Valencia-Martín JL et al., 2008; Wechsler et al., 2003] 59 Previous studies have also shown a higher risk of alcohol-related injuries among individuals 60 that present with HED, compared to those who do not show this pattern of consumption. 61 [Rehm et al., 2002; Watt et al., 2003]. Mundt, et al. found a 43% occurrence of alcohol-related 62 injuries among Heavy Episodic Drinkers compared with 10% among non-HED, and McLeod 63 has found three times the risk of these injuries among subjects who practice HED.[Mcleod et 64 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 4 al., 1999; Mundt et al., 2009]. Finally, previous studies have also shown the prevalence of 65 HED is different among both female and male college students,[Moure-Rodríguez et al., 2016; 66 Wicki et al., 2010] and HED is also significantly different from the ages of 18 to 27 years 67 old.[Moure-Rodríguez et al., 2016] Not to mention, HED’s consequences could be different as 68 well.[Caamano-Isorna et al., 2017; Kypri et al., 2009; Wiersma et al., 2002]. 69 Furthermore, it has been observed the consequences of alcohol use vary considerably in 70 different countries.[Graham et al., 2011] Despite our previous results of this cohort,[Moure71 Rodríguez et al., 2014] we are not aware of any similar longitudinal studies in European 72 countries with traditional alcohol use. 73 The objective of this study is to assess the effects of HED on the incidence of alcohol-related 74 injuries among university students in Spain, taking sex into consideration. 75 76 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 5 2. Methods 77 2.1 Design, population and sample 78 An open cohort analysis was conducted within the framework of a cohort study designed to 79 assess neurocognitive and social consequences of alcohol use. The study was carried out 80 between November 2005 and February 2015 college students from a large public university at 81 the north west of Spain. We performed a cluster sampling. From each one of the 33 university 82 schools, at least one of the freshman year classes was randomly selected (a total of 53 83 classes). The number of classes selected on each university school was proportional to its 84 number of students. All students present in the class on the day of the survey were invited to 85 participate in the study (n=1,382). Abstinent subjects and subjects who were not born in 1987 86 were excluded from the study. The study follows the principles of the Declaration of Helsinki 87 and was approved by the university ethics committee (October 2004). 88 2.2 Data collection procedures 89 Participants were evaluated via a self-administered questionnaire in the classroom in 90 November 2005 and again in November 2007. Students that provided their phone number were 91 further evaluated by phone at 4.56.5-, and 9.0year follow-up. On all five occasions, alcohol 92 consumption and alcohol-related injuries were measured using the Galician validated version 93 of the Alcohol Use Disorder Identification Test (AUDIT).[Saunders et al., 1993; Varela et al., 94 2005] At baseline and at the 2-year follow-up, participants responded to additional questions 95 about age of onset of alcohol consumption and about cannabis consumption. 96 2.3 Definition of variables 97 In order to characterize the samples, several variables were considered: sex, place of residence 98 (parental home/away from the parental home), university entrance grade (5 - <7 points; 7 - <9 99 points; and 9 - 10 points); and maternal educational level (primary school/high 100 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 6 school/university). The subjects were also asked about the age of onset of use of alcohol using 101 the following question: “At what age did you start drinking alcohol?” Four categories were 102 defined for age of onset of use (after 16 years old, at 16, at 15, before the age of 15). 103 Independent variables 104 Heavy episodic drinking (HED) at 18, 20, 22, and 24 years old. Question 3 of the AUDIT: 105 “How often do you have 6 or more alcoholic drinks on a single occasion? Never; less than once 106 a month; at least once a month; at least once a week; daily or almost daily”. The categories at 107 least once a month; at least once a week; and daily or almost daily were recategorized to More 108 frequently. In Spain, a standard drink corresponds to 10 grams of alcohol, therefore the 109 consumption of 6 alcoholic beverages in 2 hours results in blood alcohol concentration levels 110 of 0.8g/l. 111 Frequency of alcohol consumption at 18, 20, 22 and 24 years old. Question 1 of the AUDIT: 112 “How often do you have a drink containing alcohol? Never; monthly or less; two to four times 113 a month; two to three times a week; four or more times a week”. 114 Number of alcoholic drinks on a typical day at 18, 20, 22 and 24 years old. Question 2 of the 115 AUDIT: “How many alcoholic drinks do you have on a typical day when you are drinking? 1 116 or 2; 3 or 4; 5 or 6; 7 to 9; 10 or more”. 117 Cannabis consumption at 18, and 20 years old. This variable was measured with the question 118 “Do you consume cannabis when you go out? Never; sometimes; most of the times; always”. 119 The categories “most of the times” and “always” were recategorized to Usually. 120 Dependent variable 121 Alcohol-related injuries at 20, 22, 24 and 27 years old. Question 9 of the AUDIT: “Have you 122 or someone else been injured as a result of your drinking? No; yes, but not during the last year; 123 yes, during the last year”. 124 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 7 125 2.4 Statistical analysis 126 The follow-up was structured in 4 periods: 11/200511/2007 (2 years); 11/2007 – 05/2010 127 (2.5 years); 05/2010 – 05/2012 (2 years); and 05/2012 - 02/2015 (2.5 years). Because of the 128 open cohort design of the study, the conditions of subjects may have changed during follow129 up. While the 9th AUDIT question refers to alcohol related injuries suffered in the past, the 130 independent variables about alcohol consumption and cannabis consumption were referred 131 about the present. Therefore, the variable “alcohol-related injuries” measured in 11/2007, 132 05/2010, 05/2012 and 02/2015 was considered as the effect of both the number of alcoholic 133 drinks on a typical day (Question 2 of the AUDIT) and the HED (Question 3 of the AUDIT) 134 having occurred in 11/2005, 11/2007, 05/2010, and 05/2012 respectively. Since we have only 135 two measures of cannabis use (11/2005 and 11/2007), we considered the alcohol-related 136 injuries in 11/2007 as the effect of the cannabis use in 11/2005, and alcohol related injuries 137 for the rest of the periods as the effect of cannabis use at 11/2007. At each stage of the study 138 the subjects than answered “Never” to the first question of the AUDIT were excluded. 139 We used multilevel logistic regression for repeated measures to obtain adjusted Odds Ratios 140 for Alcohol-related injuries. Cannabis consumption and number of alcoholic drinks on a typical 141 day (Question 2 of the AUDIT) were also considered as independent variables, because it is 142 known that both variables can result in a lower risk perception and decreased attention, which 143 may consequently lead to injury. Adjusting by both variables, we can therefore identify the 144 specific effect associated to HED. Frequency of alcohol consumption (Question 1 of the 145 AUDIT) was also considered in order to remove the abstinent subjects. The university school 146 and the class were considered as randomized variables. The follow-up time was included as an 147 offset term. Data were analyzed using Generalized Linear Mixed Models from the SPSS 20.0. 148 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 8 Finally, in order to calculate the population impact measures, we considered the following 149 formulas.[Llorca et al., 2001] (1) To calculate the proportion of alcohol related injuries in 150 exposed subjects attributable to HED 1-(1/OR); and (2) To calculate the population attributable 151 fraction pc-(pc/OR), being pc the prevalence of exposition in ill subjects. For both formulas, 152 OR was calculated dichotomizing the HED variable (yes/no). 153 154 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 15 differences are decreasing.[Cortés et al., 2011] We have taken gender into account in our 231 analysis to assess whether these differences are maintained among college students. Our study 232 found a significant association between alcohol-related injuries and HED in men, although the 233 sample size did not permit multivariate analysis. Other studies have showed more negative 234 consequences to alcohol use in men.[Graham et al., 2011] 235 Regarding age, we can see that age greater than 23 years old acts as a protective factor for 236 alcohol-related injuries. High doses of alcohol decrease the activity of some brain regions 237 involved in error processing, prevention of compulsive actions, behavior regulation, cognition, 238 and coordination of motor activities.[Anderson et al., 2011] This could increase the risk of 239 injury. The fact that risk of injury is lower after 23 years of age can be explained by tolerance 240 developed by students, over time. Another possible reason could be that individuals at this age 241 are more mature, so they practice Binge Drinking in safer contexts and assume fewer risks, and 242 therefore injuries are less frequent.[O`Malley, 2004] 243 The fact that cannabis use was found to be risk factor for alcohol-related injuries allows us to 244 suggest that multiple drug use may be an interesting point of evaluation in future studies 245 among this population. 246 Our findings suggest that an important part of alcohol-related injuries among college students, 247 all through university period and also when this period is over, is due to HED consumption 248 pattern. Preventive measures, therefore, must be implemented in order to reduce heavy 249 episodic drinking practices among college students and so as to avoid an important part of the 250 negative consequences of alcohol consumption, such as alcohol-related injuries. It is 251 fundamental to act to reduce the accessibility of alcohol to college students through strictly 252 applied legislative measures. 253 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 16 Young people are particularly affected by alcohol prices because of their limited economic 254 resources. Therefore, administrative measures, such as raising taxes on alcoholic beverages, 255 would act to reduce their alcohol consumption.[Ivano Scandurra et al., 2011; Laixuthai and 256 Chaloupka, 1993] It would also be effective to ban promotional packaging that mixes alcohol 257 with sodas, thus promoting excessive alcohol consumption in youth. Increasing the minimum 258 legal age for alcohol consumption has been associated with fewer car accidents and suicide 259 among young people, even without tight compliance control.[Griffith, 1997] 260 Youth are especially vulnerable to alcohol promotion and publicity; binge drinkers in 261 particular seem to be the most susceptible.[Sassi, 2015] Strict policy for regulating and 262 limiting the advertisement of these products, therefore, is essential. 263 Other measures, such as brief motivational interventions or skill-based interventions, appear 264 effective among young people, specifically among college students when they are given 265 personalized feed-back.[Larimer and Cronce, 2007] College freshmen are particularly 266 disposed to these interventions and therefore a general intervention could be interesting in this 267 subpopulation.[Larimer and Cronce, 2007] 268 We must take into account that our social context may generate strong opposition to any 269 measures that try to decrease alcohol consumption. On one hand, Spanish society is quite 270 permissive with regards to alcohol use. However, Spain alcohol industry is also very 271 important -- Spain being one of the most important wine producers in the world with an 272 important tourism industry.[Calafat, 2002] 273 Our study largely confirms what is known from the literature: HED is related to alcohol274 related injuries. We do not know of, apart from our previous studies, another longitudinal 275 study in Mediterranean European Countries, which associates the HED with alcohol-related 276 injuries among college students. We must not forget that this cohort has been followed up 277 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 17 beyond the university period and the association does not disappear. This is an interesting 278 result as tends to be understood in Mediterranean countries as a pattern of consumption 279 limited to the vital period of adolescence and early youth. Our university students did not only 280 continue practicing HED after ending their university periods, they also continued suffering 281 some of its negative consequences. Our results highlight the importance of avoiding HED 282 among youth. 283 There are six main limitations to this study: 1) there is a possibility of selection bias, due to 284 loss of subjects at follow-up. However, the absence of significant differences between the 285 initial samples and the follow-up samples suggests the absence of a selection bias; 2) self286 reported data may be skewed due to inconsistent personal feelings or memories. However, the 287 AUDIT questionnaire has been internationally validated in adolescents and young adults; 3) 288 the most appropriate definition of HED in Spain implies differences between sexes: more than 289 five alcoholic beverages for women and more than six for men, on a single occasion. The 290 third question of the AUDIT therefore underestimates the prevalence of HED in women. 291 However, this limitation will mainly affect descriptive and not analytical statistics; 4) subjects 292 may have minimized the role of alcohol in the occurrence of injuries; 5) subjects were not 293 asked how many injuries they had suffered, only whether they had or had not suffered an 294 injury; 6) when subjects responded “Yes, but not in the last year” we only considered that this 295 was a new instance of injury if the subject had not reported a previous alcohol-related injury 296 in a previous AUDIT. 297 5 Conclusions 298 We can conclude that heavy episodic drinking leads to an increase of alcohol-related injuries 299 among both male and female college students. This shows a new dimension on the 300 consequences of this public concern already related with a variety of health and social 301 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 18 problems. Furthermore, our results allow us to suggest that about one third of alcohol-related 302 injuries could be avoided by removing this consumption pattern. 303 304 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 19 Acknowledgements 305 Funding: This work was supported by the Spanish National Plan on Drugs (N.P.D)(grant 306 number 2005/PN014), and MICINN (grant number PSI2011-22575). 307 The authors declare that there are no conflicts of interest. 308 309 Post-print (final draft post-refereeing) Heavy Episodic Drinking & Alcohol-Related Injuries 20 REFERENCES 310 Ahlström, S., 2011. Consumo nocivo de alcohol entre estudiantes europeos: resultados del 311 ESPAD. Manole Ltda. Brasil. 90-101. 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