Sexual Initiation, Substance Use, and Sexual Behavior and Knowledge among Vocational Students in Northern Thailand

Liu, Alice, Kilmarx, Peter, Jenkins, Richard A., Manopaiboon, Chomnad, Mock, Philip A., Jeeyapunt, Supaporn, Uthaivoravit, Wat, van Griensven, Frits, International Family Planning Perspectives

CONTEXT: Thailand has undergone dramatic social changes in the last two decades, yet little is known about factors related to sexual initiation among adolescents.

METHODS: A survey using the audio computer-assisted self-interviewing method was conducted to assess social and demographic characteristics, substance use, sexual behavior, and knowledge of HIV and STIs among 1,725 vocational school students aged 15-21 living in northern Thailand. Gender differences for these factors were evaluated using chi-square and Mann-Whitney U tests. Multivariate survival analysis using Cox proportional hazards models assessed associations between these variables and sexual initiation for each gender.

RESULTS: Males initiated sexual intercourse at an earlier age than females (median ages of 17 and 18, respectively). At any given age, sexual initiation was associated with having a nonagricultural background and using alcohol or methamphetamine (adjusted rate ratios, 1.3-2.9). For males, initiation was also associated with having parents who did not live together, having a friend as a confidant, tobacco use, high perceived risk for HIV and high STI knowledge (1.3-1.7). For females, other factors associated with earlier initiation were younger age at interview, living away from family, lacking a family member as a confidant, high perceived risk for STIs and ever having smoked marijuana (1.3-2.4).

CONCLUSIONS: Interventions to ameliorate the adverse consequences of early sexual initiation need to address social influences such as parents and peer groups. Programs should identify and target high-risk subgroups, such as those who are sexually experienced at an early age and those engaged in patterns of generalized risk-taking.

International Family Planning Perspectives, 2006, 32(3):126-135

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Among unmarried young people in Thailand, sexual behavior norms have changed substantially over the last two decades. One important change has been the increased acceptability of premarital sex among young women, which has resulted in a trend toward earlier sexual initiation for Thai females. A nationwide partner relations survey conducted in 1990 found that 13% of female participants aged 15-19 reported having had sexual intercourse, compared with 34% of males. (1) Other studies from the same period found that young Thai women had higher levels of experience, though they were still less likely to be sexually experienced than their male counterparts. (2)

Thai cultural norms generally have granted sexual freedom to males, but imposed constraints on female sexual behavior. In the past, unmarried males often experienced sexual initiation with female sex workers, and young unmarried females were expected to maintain premarital chastity.

Studies over the last decade have suggested that the norms governing sexual practices among Thai adolescents and young adults have changed. (3) A growing proportion of adolescent females report having had sexual intercourse, while male patronage of sex workers has decreased substantially. Most Thai men now have their early sexual experience with noncommercial partners. (4) Males' age at sexual initiation in Thailand does not appear to have changed in recent decades; however, as social controls have eased, young women appear to be having sex earlier. Yet a key difference remains: Young unmarried males usually have more partners, particularly more casual partners, than their female counterparts. (5)

These shifts in sexual behavior have potentially adverse consequences for Thai youth, particularly for young women. In other countries, sexually active young people have an increased risk of HIV infection and other STIs, as well as elevated rates of unplanned teenage pregnancy and pregnancy termination. (6) Understanding the factors associated with initiation of sexual intercourse is crucial in trying to design and deliver interventions for Thai youth (particularly females) who are likely to have sex at ages earlier than the norm.

Two studies have reanalyzed data from a national survey of 15-24-year-old Thais conducted in the mid-1990s (7); they focused on the association of age at sexual initiation with risk-taking behaviors, social and psychological factors, variables related to family and friends, and social and demographic characteristics. One analysis looked at the entire age range of survey participants, and the other considered only 15-19-year-olds. Several qualitative studies have also explored this subject. (8) Growing up without both parents and having sexually experienced friends were found to be associated with premarital sexual initiation. (9) For females, urban residence (10) and going to nightclubs (11) were associated with a greater likelihood of having premarital sex; for males, poor family relationships, (12) living apart from family (13) or living with parents, (14) and high levels of alcohol consumption (15) were related to a greater likelihood of premarital sexual activity.

Research in other countries has used various models to explore which factors are related to age at sexual initiation--for example, biological and behavioral correlates such as pubertal development and leisure activities, as well as social factors such as the influences of family, peers and institutions (education and religion). (16) Other studies have looked at substance use and mental health problems, but these have generally lacked an overarching conceptual framework.

In this study, we assessed factors associated with age at sexual initiation among adolescents from Chiang Rai, Thailand's northernmost province. It borders Laos and Myanmar in the Golden Triangle region, which is known for drug production and trafficking. Most of the 1.3 million people of Chiang Rai province are northern Thai and live in rural, agricultural lowlands; 13% are ethnic highland minorities ("hill tribes"). (17) The province's HIV prevalence was among the highest in the country during the early years of the Thai epidemic; (18) prevalence peaked among female sex workers in 1991 (62%), with subsequent peaks among 21-year-old male military conscripts (17% in 1993) and primigravid women (11% in 1994). Deaths among men and women aged 20-29 increased 9-10-fold in subsequent years. From analyses of the age distribution of AIDS cases and AIDS-related deaths, most HIV infection likely occurred during adolescence and young adulthood. (19)

Our sample comprised students recruited from vocational schools that provided upper secondary and post-secondary education in a variety of manual trades and occupations. The lone previous study of Thai vocational students found lower levels of HIV risk behavior among students in Bangkok than among factory workers and such traditional risk groups as clients of STI clinics. (20) Upper secondary and postsecondary education of all kinds is increasingly common in Thailand (21) and serves as an avenue for social mobility, especially for rural and urban youth in provincial areas. The schools that we sampled were located in rural and urban areas and, as vocational institutions, did not draw from the most economically advantaged strata of Thai society. Therefore, we believed they were an appropriate sample for examining sexual and drug use risks in a population exposed to recent social change.

The literature provides a limited theoretical framework for assessing the factors related to sexual initiation. We believed it was important to consider the range of social and behavioral factors that have been treated in past studies, including modifiable factors such as drug and alcohol use, recent sexual behavior, peer norms, relationships with parents, and knowledge of HIV and STIs, as well as factors that are less amenable to intervention, such as age, family structure, urban or rural residence, and family background. We also included variables that have emerged as important correlates of risk behavior in Thailand, such as sexual coercion (22) and sexual orientation. (23) This study's primary objective was to identify factors that should be incorporated into interventions aimed at improving the sexual health of Thai adolescents and young adults.

METHODS

Sample

In November and December 1999, we invited 1,736 students aged 15-21 who attended three vocational schools in Chiang Rai to participate in a cross-sectional survey of sexual and drug use behavior. After providing written informed consent (persons 15 or older do not need parental consent in Thailand), (24) 1,725 students completed computer-administered questionnaires in a classroom equipped as a computer laboratory, using monitors with hoods to maximize privacy. Equal enrollment quotas were set for males and females, as well as for each of the six grade levels in the schools. The study protocol was approved by the ethical review committee of the Thai Ministry of Public Health and by the institutional review board of the U.S. Centers for Disease Control and Prevention. A detailed description of the study procedures has been reported elsewhere. (25)

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Publication information: Article title: Sexual Initiation, Substance Use, and Sexual Behavior and Knowledge among Vocational Students in Northern Thailand. Contributors: Liu, Alice - Author, Kilmarx, Peter - Author, Jenkins, Richard A. - Author, Manopaiboon, Chomnad - Author, Mock, Philip A. - Author, Jeeyapunt, Supaporn - Author, Uthaivoravit, Wat - Author, van Griensven, Frits - Author. Journal title: International Family Planning Perspectives. Volume: 32. Issue: 3 Publication date: September 2006. Page number: 126+. © 2008 Guttmacher Institute. COPYRIGHT 2006 Gale Group.

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