Background

It is well established that an increase in alcohol consumption leads to a higher proportion of persons with problem use and addiction. In 2007, the National Statistical Office of Thailand found 29.3% of Thais ≥ 15 years old consume alcohol. The proportion of male alcohol consumption in the age 25-59 years was 59.1%, 15-24 years 39.2% and over 60 years 29.4%, respectively [1]. It was found that the proportion of male drinkers increased from 55.4% in 1996 to 60.8% in 2003, but dropped to 50.3% in 2006 and 51.0% in 2007 [1, 2]. During 1996-2006, the proportion of male drinkers has risen in young people, particularly those aged 15-19 years (20.8% to 24.2%) and aged 20-24 years (56.0% to 58.1%) [2]. Reports from the National Statistical Office of Thailand in 2007 showed the major alcoholic risk groups were working people and youths. Alcohol drinking is frequently related to behavioral problems, which lead to a number of negative consequences, such as domestic violence and quarrels with neighbors, suicides and sexual assault and risky sexual behaviors. It also accounts for numerous accidents such as injuries and traffic accidents. Youths who drink have a greater tendency to develop those health-risk behaviors.

The aim of this study was to evaluate the characteristics of male high school students who drink, the drinking patterns among them, and the associations between current drinking and other health risk behaviors which focused on personal safety, violence-related behaviors, suicide and sexual behaviors.

Methods

Study design and population

A cross-sectional study was conducted from December 2007 to February 2008 in order to explore current drinking and health-risk behaviors among male high school students in central Thailand. The proposal was reviewed and approved by the Ethics Committee for Research in Human Subjects of Mahidol University (Ref.No. Mu 2007-243). A two-stage stratified sampling technique was used to select the 5,184 students from 10 provinces of central Thailand within the academic zones 5, 6, and 12. The primary sampling unit was province and the second was school. These provinces were randomly selected and represented characteristics of male adolescents in central Thailand. In each province, we randomly selected at least one school from the list of each of the three school categories: urban and rural public schools, and private schools. The selection of schools was based on a list of schools obtained from the Provincial Education Offices and willingness of school administrators to participate in the study. Selected schools could refuse to participate in the study. Altogether, 5,184 students from Mathayomsuksa School (MS) 1, 3 and 5 participated in the study (equivalent to grade 7, 9 and 11 of an ordinary school). In each school, 3 or fewer classes of each of these 3 educational levels were recruited from the same grade level. If there were more than three classes, three classes with students of mixed academic performance were randomly selected by their teachers. The study subjects were classified into 2 groups according to their alcohol intake during the 30 days preceding the survey (yes = 631, no = 4,553). Information was collected by a self administered, anonymous questionnaire which consisted of 3 parts, socio-demographics, health-risk behaviors during past year and alcohol drinking behavior with the help and supervision of well trained research assistants. Current drinking was defined as drinking at least one standard drink of an alcoholic beverage during the past 30 days of the survey. A standard drink was defined as a can (330 cc) of beer, a glass (100 cc) of wine, or a small glass (30 cc) of whisky or spirits. The health-risk behaviors questionnaire was modified from the questionnaire of the U.S. Youth Risk Behavior Surveillance System [3, 4] and focused on personal safety, violence-related behaviors, suicide and sexual behaviors. The Thai version was translated and verified by a bilingual English university lecturer, and it was reviewed by the experts (composed of psychiatrists, psychologists, nurse, social workers, school teachers and health promotion specialists). Details of the study were explained and an informed consent form was signed. Individual answers were kept confidentially.

Statistical analysis

Socio-demographic factors were given as a percentage, crude odds ratio, 95% CI of OR and p-value. Univariate analysis was performed using the Pearson's chi-square test to differentiate proportional exposures between drinkers and non-drinkers for categorical variables. Adjusted odds ratio and the 95% CI of OR were calculated from multiple logistic regression to examine associations between current drinking and health-risk behaviors, adjusted for socio-demographic factors. A criteria of p < 0.05 for statistical significance was applied.

Results

A total of 5,184 male high school students, their percents of alcohol consumption in the past 30 days were 12.17. Current drinking prevalence increased with increasing age (6.41% among less than 15 year-olds vs 26.54% among 18 years and older) and grade level (4.73% among 7th graders vs 22.08% among 11th graders).

Using a univariate analysis, the factors significantly associated with current alcohol drinking assessed by a Pearson's chi-square test (p < 0.05) were age group (OR 15-17 yrs = 2.92; 95% CI = 2.40-3.53; OR ≥18 yrs = 5.28, 95%CI = 3.59-7.76), educational level (OR MS 3 = 3.06, 95% CI = 2.38-3.95; OR MS 5 = 5.74, 95% CI = 4.46-7.40), residence (OR school dormitory = 1.82, 95% CI = 1.07-3.08), cohabitants (OR friend = 2.93, 95% CI = 1.76-4.87), as well as GPA (OR GPA < 2.0 = 1.36, 95% CI = 1.05-1.76; OR GPA > 3.0 = 0.42; 95% CI = 0.32-0.56), having a part time job (OR = 1.47, 95% CI = 1.22-1.76) and having family members with alcohol/drug problems (OR = 1.26, 95% CI = 1.05-1.51) (Table 1).

Table 1 Socio-demographic factors associated with current drinking of male high school students
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Other health risk behaviors were more common among current drinkers. After adjusting for socio-demographic factors (age, educational level, residence, cohabitants, GPA, having a part time job, and having family members with alcohol/drug problems), compared with non-drinkers, current drinkers were more likely to drive a car/bicycle after drinking alcohol (OR = 3.10, 95% CI = 1.88-5.12). For violence-related behaviors, often carrying a weapon (OR = 3.51, 95% CI = 2.27-5.42), often getting into a physical fight without injury (OR = 3.06, 95% CI = 1.99-4.70), and experience dating violence (OR = 2.58, 95% CI = 1.79-3.71) were proportionally higher among current drinking students than non-drinkers. In addition, sad feelings and attempted suicide, indicated that participants had seriously thought about suicide (OR = 2.07, 95% CI = 1.38-3.11) and making a suicide plan (OR = 2.10, 95% CI = 1.43-3.08) were also significantly associated with current drinking. In case of sexual behaviors, higher proportions of ever having sexual intercourse (OR = 5.62, 95% CI = 4.33-7.29), alcohol or drug use before last sexual intercourse (OR = 2.55, 95% CI = 1.44-4.53), and getting someone pregnant (OR = 3.99, 95% CI = 1.73-9.25) were found among current drinkers than among non-drinking students, as shown in Table 2.

Table 2 Percent, crude OR and adjusted OR of health-risk behaviors among male high school students according to drinking status
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The majority of boys drank alcohol less than 3 times a month (59.83%) and they each consumed less than 3 standard drinks in the previous month (38.59%). Approximately 40% of boys drank more often than twice a month and 39% of them drank more than 4 standard drinks each time. Alcohol consumption was more common when joining a party (45.68%) but a high proportion of boys drank at home/dormitory (36.33%). Nearly 70% of respondents experienced binge drinking within 2 weeks and nearly half of them admitted to being intoxicated during the 30 days prior to participating in this study, as shown in Figure 1, 2, 3, 4 and 5.

Figure 1
figure 1

Frequency of drinking in the previous month.

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Figure 2
figure 2

Quantity of drinking each time in the previous month.

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Figure 3
figure 3

Places of drinking.

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Figure 4
figure 4

Frequency of drinking each time ≥5 drinks within 2 weeks.

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Figure 5
figure 5

Frequency of drinking until intoxication in the previous month.

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Discussion

The present study found an increased risk of health-risk behaviors, including intentional injury-related behaviors, suicidal behaviors and premature sexual behaviors among drinking and non-drinking students. This study is one of a few studies on underage drinking among high school students in a developing country of the South-East Asian region. Our findings demonstrated that approximately 12% of male high school students reported that they drank alcohol during the 30 days preceding the survey. This figure was also lower than the studies of Miller et al, 2007 [5], Johnston et al, 2008 [6] and Assanangkornchai et al, 2007 [7]. Even more alarming, we found that among students who drink, almost 70% reported binge drinking (drinking ≥ 5 drinks of alcohol in a row at least once during the past 2 weeks) and half of them had experienced drunkenness. Heavy episode drinking in adolescence is associated with several serious consequences; such as motor vehicle injuries, suicide, sexual assault and risky sexual behaviors with the danger to acquire sexual transmitted diseases and unwanted pregnancies [8]. Adolescence is a vulnerable period and facilitates the start of risk behaviors, for instance consuming alcohol, cigarette smoking and substance use. This study confirmed that older boys drank more than the younger ones [5, 9–13]. Non-drinkers had lower rates of health risk behaviors compared with current drinkers. This study also confirmed that current drinking is associated with driving a vehicle which corresponds with the results of the study of Domingues et al, 2009 [14]. Eaton found 10% of high school students had driven a car or other vehicle one or more times when they had been drinking alcohol [15]. Alcohol is associated with much of the mortality and morbidity among youth. In addition, alcohol drinking and drunk driving are a major factor causing road traffic accidents. The percentage of Thai male drunk drivers has risen from 36.6 in 2001, to 48.2 in 2002 and 44.1 in 2006 [2]. In aspect of violence-related behaviors, current drinkers are at higher risk of often carrying a weapon [16–18], getting into a physical fight without injury [5] and dating violence [5, 19–21]. In addition, according to the present study (see table 2 above) drinkers are at higher risk of seriously thinking about suicide and making a plan how they would attempt suicide. This corresponds with the results of the previous studies [5, 22–24]. In sexual behaviors, this study also confirmed that higher levels of alcohol consumption are associated with ever having sexual intercourse [5, 20, 25], alcohol/drug use before last sexual intercourse [5, 26] and getting someone pregnant [5, 22, 27].

Limitation of the study

Some limitations of this study should be noted. First, the study was a cross-sectional study, therefore, a temporal relationship cannot be established between alcohol consumption and the health-risk behaviors. A longitudinal study would be needed to examine causal effects of drinking on subsequent drinking. Second, all data were obtained through self-reports, which may lead to inaccuracies of alcohol drinking [28–31] and other health-risk behaviors.

Conclusions

An increased risk of health-risk behaviors, including driving vehicles after drinking, violence-related behaviors, sad feelings and attempted suicide, and sexual behaviors was higher among drinking students that led to various health problems. The results from this study show prevention of underage drinking is needed. Law enforcement, namely minimum age of purchasing alcohol ≥ 20 years, increasing the penalty of drunk driving, and limiting the availability and accessibility of alcohol through restrictions of times and places should be done strictly. The results suggested that effective intervention strategies among adolescents should be implemented to prevent underage drinking. Applications of the health promoting school model of WHO [32] should be utilized to develop the effective school health programmes to relieve these problems. Some papers showing the effectiveness of Health Promoting School in minimising health-risk behaviors [33–39]. Therefore attempts should be made to limit youth access to alcohol in order to reduce accidents, injuries, violence and alcohol-related health problems [40]. A campaign mentioning the adverse health effects and social consequences to the risk groups, and encouraging parental and community efforts to prevent youth drinking and other health-risk behaviors would reduce the proportion of new and current drinkers and other adverse consequences. The results obtained from this study indicate that to prevent drinking among adolescents need a rather sophisticated approach and more studies to explore the cultural and socio-economic background of current youth drinkers.