|Alcohol; Adolescents; Young adults; Substance use
|The consumption of alcohol among adolescents has increased in
the last decades, being its pattern of initiation increasingly early . The
concern about alcohol consumption in adolescence in the developed
countries has become a matter of debate, particularly in terms of public
health, but also of social and cultural relevance. For this reason, health
campaigns warning on the effects of excessive consumption have been
promoted and legislated. However, the effectiveness of these measures
in slowing the use of these substances still needs to be demonstrated
|In the US in 2011, a report from the National Center for Chronic
Disease Prevention and Health Promotion has indicated that one in
eight of US women reported binge drinking and that one in five high
school female students who consume alcohol also reported binge
drinking. The report also states that female adolescents are catching
up quickly adolescent male when it comes to compulsive drinking and
excessive consumption of alcohol, which results in 23,000 deaths of
women and girls per year in the US .
|Consequences of alcohol abuse
|The consequences of alcohol abuse are severe and may impact on
individual, familiar and social levels . The physical deterioration due
to chronic alcohol abuse is one of the main problems in patients with
alcohol dependence syndrome . Alcohol abuse is associated with
multiple diseases, which range from cardiac diseases  and certain
types of cancer  to neurological syndromes [8,9].
|In adolescents, several studies have shown that mortality associated
with alcohol consumption usually results from negligence of basic
safety rules (unintentional injuries) such as those resulting from driving
under the influence of alcohol  or even, homicide or suicide, the
latter with a higher incidence in females .
|Risks and protective factors for alcohol consumption
|The identification of risk factors plays a key role in structuring and
adaptation of prevention programs linked to alcohol consumption,
especially when consumption appears in childhood/adolescence .
There are some factors that may predict later alcohol abuse. These factors
such as unstable family environments, along with parents’ alcohol
consumption and low education levels, but also individual factors such
as behaviour problems in school are among the most relevant predictors
for binge drinking in both male and female adolescents [12,13]. At the
same time, other studies also suggest that permissive behaviour from
parents is related to early onset risk behaviours in adolescents  and
highlight the importance of monitoring, communication and family
supervision on the risks that young people face in their lives .
|Along with individual and family risk factors, Whiteman et al. 
sought to determine the influence of role models and their modelling
effect on behaviour. In siblings, this influence may be exerted in
two ways, in which younger siblings may be influenced positively
or otherwise may lead them to deviant behaviour. The contact with
peers can have a beneficial or detrimental effect. There is evidence
that the activities carried out together with friends and neighbours
have a positive effect, related though to a higher probability of alcohol
consumption, particularly in boys . In addition, boys also show a
higher tendency to become involved in situations of aggression and
violence as a result of alcohol consumption away from home, whereas
violence in girls was linked to alcohol consumption at home . Thus,
interventions to reduce aggressive behaviour must include not only
alcohol abstinence/reduction, but also individual and environmental
risk factors . Other environmental risk factors also include the
role of advertising of alcoholic drinks, which have a strong impact on
adolescents, but schools are also more involved to educate their students
about the dangers of excessive alcohol consumption and to keep alcohol
out of reach of younger students .
|In contrast, some studies have also shown that parents’ direct control techniques on children’s supervision may be protective factors for
alcohol abuse, being associated with a lower probability of alcohol use,
tobacco and drugs, while may be considered as an effective technique
when children remain close to their parents. However, this monitoring
strategy is increasingly difficult to achieve as children grow, as they are
gaining autonomy and freedom. In these circumstances, parents should
develop indirect control techniques simultaneously, such as knowledge.
The control techniques (direct and indirect) appear also to be associated
significantly with a decrease in delinquent behaviour .
|Given the influence of multiple risk factors in the severity of
alcohol consumption, the specific contributions of individual, family
and social/environmental risk factors on alcohol consumption are not
yet known. A couple of studies carried out in Portugal in the last five
years have showed that the prevalence of alcohol consumption is high
in school adolescents, especially in terms of binge drinking that are
at the levels of the US . The objective of our study was therefore
to explore the most relevant risks for alcohol consumption among a
sample of Portuguese adolescents and young adults. These predictors
were retrieved from the Global School-based Student Health Survey
(GSHS), a well-known instrument to assess behavioural risk factors and
protective factors in several different topics associated with morbidity
and mortality among children and adults worldwide. In the current
study we have used the module regarding alcohol uses, which comprise
items related to 1) alcohol use, 2) role of the media and advertising, and
3) knowledge, attitudes, skills, and sources of information.
|The sample comprised 364 adolescents/young adults, 162 male
(45%) with a mean age of 18.06 years old (SD=1.46) and 202 female
(55%) with a mean age of 17.92 years-old (SD=1.32). The mean years
of schooling were of 11 years (SD=1.50) for the whole sample. Most
of these participants live with both their parents (52%). Regarding
parental monitoring strategies, the majority of the participants are
allowed to go out at night (89%), and do not have a specific time to
return home (68%), but parents know where they are (90%). Most of
the participants reported that the main motivation to drink alcohol was
to be with their friends (64%), but also that it is not usual to have a
drink offered by a stranger (92%), that alcohol consumption was not
crucial to have sex (87%), and that 92% of them had sex with strangers
after consuming alcohol (92%). Table 1 presents the descriptive analysis
on sociodemographic and alcohol-related data.
|Bivariate analyses were conducted to assess whether these
distributions vary as a function of gender. Chi-square tests only showed
a significant association with gender for the question “Have you ever
had sex with strangers after consuming alcohol?” (χ2 (1)=14.253;
p=0.000), having more boys reporting yes than girls. Moreover, no
statistical significant differences were found between gender and
quantitative variables of age and education (p>0.05).
|The survey was divided into two sections. The first section included
questions regarding sociodemographic information, such as gender,
age, years of schooling, family structure and marital status of the
|In the second section we used the GSHS, which is a survey
developed by the World Health Organization (WHO) and Centres for Disease Control and Prevention (CDC) in collaboration with the
United Nations - UNICEF, UNESCO and UNAIDS.
|This survey was devised to assist countries in the evaluation of
behavioural risk factors and protective factors in ten leading causes
of mortality and morbidity among children, adolescents and adults
worldwide, namely: alcohol use, dietary behaviours, drug use, hygiene,
mental health, physical activity, protective factors, sexual behaviours,
tobacco use, violence and unintentional injury.
|The development of this instrument was conducted mainly in
students aged between 13 and 17 years old. In the current study, we
have used the module related to alcohol consumption of the GSHS.
It is worth mentioning that the different modules of the GSHS can
be implemented separately. The items of this section (26 items) are
intended to assess the consumption of alcohol at present, the amount of
alcohol consumed, how the participants get alcohol, episodes of alcohol
intoxication, and problems associated with alcohol consumption. The
response format is Likert style in most of the questions-the exceptions
are dichotomous and nominal response formats. This module is
divided into three subsections: 1) general questions regarding alcohol
use, which refer to the participant and their parents (Questions 1 to
14); 2) role of the media and advertising (Questions 15 to 21); and 3)
knowledge, attitudes, skills, and sources of information (Questions 22
to 26). The reader can find more information about the questionnaire
as well as the English and Spanish versions of the GSHS at the WHO
|The current version of the GSHS is originally available in English and
Spanish. Thus, the first step of this study was to translate the instrument
to Portuguese language. We have conducted the translation/adaptation
of the module related to alcohol consumption by three independent experts in Psychology and Social Sciences with high proficiency in
Portuguese and English languages. The retroversion of the Portuguese
versions was done by a different expert with background in the same
scientific area, which revealed a high correspondence between both
modified and original versions.
|The data collection was made in Lisbon in specific places known as
popular to go out at night in Lisbon, namely at Bairro Alto and Santos in
Lisbon downtown. Only alcohol users were included in the study. The
participants were recruited under a convenience sampling method, in
which they were approached individually and were explained the topic
of study. This was held on Fridays and Saturdays, at night, between 9 pm
and 1 am, between the months of February and April. After informed
consent, the participants filled out the self-report questionnaire, which
included a sociodemographic section and the alcohol module of the
GSHS. Completion of the assessment protocol was made individually
and took approximately 6 to 15 minutes.
|We excluded 22 participants from the study due to problems
detected when filling the questionnaire (incomplete questionnaires
with missing responses).
|The statistical analyses were carried out using SPSS v.20 (IBM
Corporation). Given the main objectives of this study - to determine
the most relevant risk and protective factors associated with alcohol
consumption in adolescents and young adults; the statistical analyses
were based on 1) descriptive statistics on the associated risk factors
under study, 2) Chi-Square analysis to test the association between
factors and the outcome and 3) regression analysis to determine the
most important predictors of the outcome. The outcome was defined
as alcohol consumption severity in the last 30 days, assessed through
the Q5 “During the past 30 days, how many times did you drink so
much alcohol that you were really drunk?” The significant associations
were further explored using a logistic regression analysis to test the best
predictors of this outcome as well as to estimate the Odds Ratio (OR)
through Exp (B) for the effects of each predictor on the outcome.
|The descriptive analysis for items from the GSHS showed that most
of individuals (37%) sometimes viewed alcohol advertisements (Q1),
46% drink beer more frequently (Q2), 36% reported having some friends
drinking more than 5 drinks on one occasion (Q3), 39% reported that
the first time had been drunk was over 16 years-old (Q4); 51% have
not been drunk in the past 30 days (Q5), most of the individuals (92%)
did not get into trouble because of alcohol (Q6), none of the parents
drink alcohol in 31% of individuals (Q7), the bar, pub or disco are the
most common places (53%) where individuals drink alcohol (Q8), 91%
usually drink with their friends (Q9), most of the individuals (64%) are
allowed to drink at home (Q10), in 73% of the individuals, age usually
it is not a problem to buy alcohol (Q11), most of individuals (45%) have
brother and sisters that drink alcohol (Q12), most of their friends (55%)
drink alcohol (Q13), in 85% of the individuals, parents know that they
drink alcohol (Q14).
|Regarding section “Role of the media and advertising”, 45% of
individuals sometimes watch actors drinking alcohol when watching
television (Q15), as well as for advertisements for alcohol in social
events (40% - Q16), most of individuals (53%) reported having seen
a few advertisements for alcohol in in the television (Q17), billboards
(55% - Q18), in newspaper or magazines (52% - Q19) and on the
internet (49% - Q20), most of individuals did not have any article with an alcohol brand (64% - Q21).
|As for section “Knowledge, attitudes, skills, and sources of
information”, 55% reported that probably would accept a drink from
a friend (Q22), 71% indicated that would be very easy to get alcohol
(Q23), most of the individuals reported not have been taught in school
for the problems associated with drinking alcohol (62% - Q24), the
effects of alcohol use on decision making (63% - Q25), and how to tell
someone to refuse to drink alcohol (73% - Q26). The distribution of
these proportions in each of the variable is depicted in Table 2.
|Following this analysis, we have tested the association between the
outcome and the associated risks from the GSHS by using Chi-square
estimates. It is worth noting that no significant associations were found
between the outcome and gender (p>0.05).
|The results for the associated risks from the GSHS showed
significant associations between the outcome and items Q2 (χ2
(7)=30.358; p=0.000), Q3 (χ2 (4)=26.906; p=0.000), Q4 (χ2 (6)=54.485;
p=0.000), Q6 (χ2 (3)=26.272; p=0.000), Q7 (χ2 (4)=11.661; p=0.020),
Q8 (χ2 (6)=13.336; p=0.038), Q9 (χ2 (4)=24.715; p=0.000), Q10 (χ2
(2)=13.315; p=0.009), and Q13 (χ2 (4)=11.935; p=0.018).
|For the section “Role of the media and advertising”, the results only
indicated significant associations between the outcome and items Q20
(χ2 (3)=10.801; p=0.013), and Q21 (χ2 (1)=16.098; p=0.000).
|Finally, in “Knowledge, attitudes, skills, and sources of information”
only item Q22 (χ2 (3)=23.047; p=0.000) was found to be significantly
associated with the outcome.
|The above mentioned variables in which was observer a significant
association with the outcome were then included in a logistic regression
analysis as predictors of the outcome. The outcome was transformed
in a binary variable, coded with 0 (corresponding to the original first
category “0 times”) and 1 (aggregating the original last 3 categories).
The associated risks were transformed into dummy variables for each
level (0 - absence of the attribute; 1 - presence of the attribute).
|The logistic regression analysis was done separately for the group of
items describing a) Individual and social risks for alcohol consumption,
b) Role of the media and advertising, c) Knowledge, attitudes, skills,
and sources of information. The binary variables were included into
different blocks according to each item of the questionnaire. The
method used for variable extraction was Forward Wald.
|The first regression model was obtained for the individual and
social risks that revealed a significant model with 0.32 (Nagelkerke R2)
of variance explained by the predictors, being the model statistically
significant (χ2 (14)=100.147; p=0.000).
|The most relevant predictors found were retrieved from item Q6 - 1
or 2 times get into trouble because of alcohol (OR=22.069) and item
Q4 - had been drunk at 12 or 13 years of age (OR=11.980). These and
the odds ratio for the remaining significant predictors can be found in
|As regards to the items from the section “Role of the media and
advertising”, the analysis showed that item Q20 – viewed a lot of
advertisements for alcohol on the Internet, and item Q21 – to have an
item with an alcohol brand logo may explain alcohol consumption. The
variance explained was low, R2=0.03 (Nagelkerke R2), but the resulting
model was still significant (χ2 (14)=21.805; p=0.000) with Q20 option
|The regression analysis for each level of item Q22 “If one of your best
friends offered you a drink of alcohol, would you drink it?” regarding knowledge, attitudes, skills, and sources of information section,
indicated that the levels “Definitely not” and “Definitely yes” were the
best predictors of alcohol consumption, but in opposite directions:
(OR=0.120) and (OR=2.364), respectively. The variance explained by
the predictors was R2=0.08, being this model significant through the
Chi-square statistic (χ2 (2)=23.770; p=0.000).
|In this investigation we aimed at studying the role of individual,
social and environmental factors on alcohol consumption among
adolescents and young adults that go out at night. We have developed a
survey with questions inquiring about the role of individual factors, but
it also included the GSHS, which allows a comprehensive assessment
of social and environmental aspects that may contribute to alcohol
consumption. This study reports the data from a sample of adolescents
and young adults that were recruited in Lisbon nightlife.
|Surprisingly, our results did not show an influence of gender on
alcohol consumption, which is in agreement with the data from the
report of the National Center for Chronic Disease Prevention and
Health Promotion  that suggests a growing trend of alcohol abuse
among women. Particularly, these findings suggest that girls are at high
risk for alcohol-related harms, because the physiological tolerance to
alcohol is lower in women than in men .
|Despite these results, there are other studies indicating that the
average level of alcohol consumption remains higher in boys in late
|Moreover, the strongest factors associated with alcohol consumption
were get into trouble because of alcohol and earlier onset of alcohol abuse, with adolescents that were involved 1 or 2 times into trouble or
those who get drunk at 12 or 13 years old were more likely to consume
alcohol. It was also shown that having beer as the most common drink
predicts also alcohol consumption. These results suggest a link between
problematic behaviours and alcohol consumption such as evidenced
in boys . On the other hand, these results may also highlight the
need for proper parental guidance and awareness, particularly in early
adolescence, because early onset of alcohol consumption may put
adolescents at great risk of later alcohol abuse and dependence .
|The early initiation of alcohol consumption has been defined as one
of the most relevant predictors for future health problems. Drinking
alcohol before age 16 was significantly associated with an increased risk
for excessive drinking in adulthood, both in male and female .
|Our results suggest also that being frequently exposed to alcohol
advertisements on the Internet might explain alcohol consumption
in adolescents and young adults , which may also highlight the
importance of parental control on Internet use .
|Furthermore, the question inquiring, “If one of your best friends
offered you a drink of alcohol, would you drink it?” resulted in two
different predictors of alcohol consumption. Accepting drinks
(definitely yes) from a friend was more likely to be associated with
alcohol consumption than not accepting drinks (definitely not), which
is in line with previous results from Pavlova and colleagues ,
emphasizing the role of peers in alcohol consumption.
|The literature has shown that initial drinking experiences occur
mostly in individuals with friends who already have drinking habits .
It is therefore important that technicians who work with adolescents
raise awareness about this subject and help parents supervising their children’s behaviour. Although this was not an experiment manipulating
the role of Internet advertisement, our overall results suggest that it
is important that society promotes a sense of social responsibility in
how alcohol brands advertise their products, disapproving alcohol
advertising on media or events that may be directly available to children
|However, one of the main limitations of this study is related to the
lack of control of alcohol levels. It was our concern to include in the
study only participants that were not drunk, but recruitment did not
included formal alcohol testing. We recommend that further studies
control for alcohol levels using alcohol testing (e.g., breath alcohol
tests). It will be important also that future research include more
representative samples than only adolescents/young adults that go out
at night in the weekend.
|Overall, the obtained results suggest a stronger association of the
outcome (alcohol consumption) with individual risk factors that include
problematic behaviours, but also other related to onset of alcohol abuse.
On the other hand, there was also an association of the outcome with
environmental factors such as exposure to Internet advertisements that
may explain alcohol consumption. The role of peers, particularly as
regards to accepting drinks from friends was also a relevant predictor
of alcohol consumption.
|The authors declare that no funding was received for this study.
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