1 Department of Community Health and Epidemiology, Queens University.
2 Current affiliation: Department of Epidemiology and Biostatistics at the University of Western Ontario, Canada.
3 Department of Community Health and Epidemiology, Queens University and Kingston, Frontenac, Lennox and Addington Health Unit.
4 Department of Community Health and Epidemiology, Queens University.
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Abstract |
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Methods A cluster randomized design randomizing high school classes in Belize City. Subjects were 1319 years old.
Results Seven schools in Belize City were selected; 8 classrooms were randomized to the intervention arm and 11 classrooms to the control arm (N = 399). The intervention was associated with two more correct answers on the post-test (difference score was 2.22 points, 95% CI = 0.53, 3.91) after adjusting for gender and previous sexual experience. After controlling for gender and previous sexual experience, the intervention was associated with no change in the attitudes (0.06, 95% CI: 2.89, 2.82) or behavioural intent domains (0.84, 95% CI: 1.12, 2.46).
Conclusions Greater changes in knowledge were observed in the intervention group than in the control group following the intervention. Changes were not observed for the attitude or behavioural intent domains. These results and the results of similar studies may be used to further improve sex education programmes as it is imperative that students have access to the information necessary to make informed decisions regarding their sexual health.
Accepted 30 September 2002
There are several good reasons to study sex education and its use in the adolescent population. Around the world, and particularly in developing countries, the age of marriage is increasing and the number of adolescents is growing. This places increasing numbers of adolescents at risk for premarital pregnancy and sexually transmitted diseases (STD).1 Premarital pregnancies are more likely to be unplanned, and unplanned pregnancies have been shown to increase the risk of maternal and child mortality, and morbidity.2,3 Later age at marriage also contributes to exposure to a larger number of sexual partners which is associated with higher rates of STD including human immunodeficiency virus (HIV).47 The only known protection against these diseases is abstinence or the latex condom, yet it is estimated that less than 10% of unmarried sexually active adolescents in developing countries are using condoms.8
Relatively little is known about the sexual knowledge and experience of adolescents in developing countries, yet they make up a large proportion of the population in these countries.912 This is the case for Belize where it is estimated that 42% of the population are under the age of 15 and 6% are over the age of 60 years.13 Belize is experiencing increasing problems with STD including HIV/AIDS. The number of people infected with HIV is estimated to be 925 infected individuals per 100 000 people;14 in 1996 the AIDS annual incidence rate was estimated to be 161.7 per 1 000 000.15 Mortality rates in Belize from communicable diseases are third highest in Central and South America, after Ecuador and El Salvador (age- and sex-adjusted rates for 19952000).15 The question remains as to the best way to educate individuals about sex and sexuality in developing countries. Unfortunately, there exist little data to support a decisionsince methodologically sound evaluations of sex education programmes in schools are rare in developing countries.16
The most recent systematic review of randomized controlled trials (RCT) of adolescent pregnancy prevention programmes calls for future research into sex education programmes developed from suggestions made by young people that emphasize negotiation skills in sexual relationships and communication.17 The Responsible Sexuality Education Program (RSP) is one such programme. The programme is based on Banduras Social Learning Theory and was developed with input by high school and university students. It is felt that programmes based on social learning theory are the most effective in influencing behaviour and do so by using modelling, role playing, and shaping techniques.1820 The programme is a 3-hour scripted responsible sexuality education intervention which provides a framework for adolescents for decision making in relationships and provides unbiased information about sex and sexuality. According to behaviour theory, if the aim of sex education is to improve the safe sexual behaviour of individuals, the first aim must be to improve knowledge, and then foster safer attitudes and behavioural intentions.12,21 Therefore this studys objectives were to evaluate changes in knowledge, attitudes, and behavioural intent following the RSP. This study was conducted to gain a better understanding of the effectiveness of the RSP and also to better understand the role of sex education in Belize high schools.
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Methods |
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An a priori sample size requirement was calculated to be 513 students, using 0.05 as the estimated intra-cluster correlation coefficient. This sample size was adjusted for possible loss-to-follow-up and was calculated to provide 80% power, at = 0.05, to detect a change score of 1.8 points in the knowledge domain, a difference estimated to be clinically meaningful.22,23 A sampling frame of all high school classrooms from seven available high schools was obtained and 19 classrooms randomly selected for study (based on classroom N = 27). Allocation into intervention and control arms was achieved by flipping a coin. Data were collected using a 79-item questionnaire. Parts One and Two examined attitudes and behavioural intent rated on a five-point Likert scale. Part Three examined knowledge using 20 true/ false/dont know questions. Information on age, gender, and previous sexual experience was also collected. As a measure of internal consistency for the questionnaire, Cronbachs alpha was calculated for each of the domains of knowledge, attitudes, and behavioural intent at pre-test.
In order to evaluate the RSP, the comparison of interest was the change in knowledge, attitudes, and behavioural intent for the intervention group compared with the control group. Students in the intervention and control arms were compared with respect to age, gender, and previous sexual experience as well as baseline levels of knowledge, attitudes, and behavioural intent.
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Statistical analysis |
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Results |
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The results of the main analysis are presented in Table 4. A more detailed table presents the percentage correct by question for both the intervention and control groups for the knowledge domain (Table 5
). The comparison of interest was the change in knowledge, attitudes, and behavioural intent for the intervention group compared to that of the control group. For the knowledge domain the intervention was associated with an average of two more correct answers on the post-test (difference score was 2.22 points, 95% CI: 0.53, 3.91) after adjusting for gender and previous sexual experience. The intervention was associated with no change in the attitudes or behavioural intent domains. Both crude and adjusted analyses are presented. The adjusted analyses took into account the influence of previous sexual experience.
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Discussion |
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One weakness of this study includes the questionnaire tool used to assess change. After data collection, Cronbachs alphas were calculated for each of the three domains of knowledge, attitudes, and behavioural intent. The knowledge domain is consistent in the measurement of a knowledge concept with a Cronbachs alpha of 0.70 which reaches the recommended range and also the range of alphas for knowledge domains from other studies.12,18 On the other hand, Cronbach alphas for the other two domains, attitudes and behavioural intent, were low, which may be a reflection of the difficulty of measuring these concepts. Due to this difficulty with measurement, results for attitudes and behavioural intent should be interpreted with caution.
Two remaining weaknesses in this study relate to the randomization process. Randomization was performed according to classroom rather than school to provide variability in the assignment of intervention and control according to socio-demographic characteristics of the seven high schools included, even though one previous study has shown that similar results are obtained regardless of which entity is randomized.30 Although control arm contamination within schools is a potential weakness, the effect, if any, is likely to be minimal because interaction between classrooms within schools was limited.
The second weakness of the randomization process is the imbalance between the intervention and control arms with respect to gender and previous sexual experience. This imbalance in both gender and previous sexual experience may be explained wholly due to the randomization imbalance by gender-specific classes, as gender and previous sexual experience were associated with one another in the population studied, with more males indicating they had engaged in sexual intercourse (56%) than females (18%). Because this study used a cluster randomized design the imbalance of classes amplified the imbalance of subjects. After randomization there were five co-ed, one all male and two all female classrooms on the intervention arm. On the control arm there were four co-ed, one all male and six all female classrooms. Unfortunately information on the constellation of gender-specific classrooms was not available at the time of randomization therefore stratified randomization could not be performed. Stratified randomization would have increased study efficiency by balancing gender, and therefore previous sexual experience, between study arms and prevented them from becoming potential confounders. Overall validity of study results were not affected, however, since both gender and previous sexual experience were adjusted for in the multivariable analyses. Mean age was not significantly different between the intervention and the control group, and therefore could not be a confounder. It is a concern that the study arms may also be unbalanced on unknown confounders, such as socioeconomic status, ethnicity, substance use, and involvement in trading sex for money. Information on factors that may be of concern in this regard could not be collected.
Many studies have evaluated sex education programmes and several reviews, as well as one meta-analysis, have summarized the literature regarding the effectiveness of pregnancy prevention programmes for adolescents.3036 The most recent review is of 26 published and un-published RCT evaluating adolescent pregnancy prevention programmes (including sex education classes, abstinence programmes, family planning clinics, and community-based programmes).17 In this review the authors conclude that these programmes do not delay sexual intercourse or increase birth control use. However, large heterogeneity of results existed across studies and both positive and negative studies were included in those rated highest for methodological rigour. This heterogeneity may be due to attempts to summarize overall effects from studies that evaluate different educational programmes, in different populations and with variable lengths of follow-up. Most importantly, this systematic review included only RCT in developed countries (North America, Western Europe, Australia, and New Zealand) where the intervention being evaluated was consistently being compared to a conventional intervention.17 Therefore this overall lack of effect observed in the systematic review, as the authors indicate, could be due to the inability of the new intervention to exceed the effect of the conventional intervention and not due to the fact that these programmes have no positive effect on knowledge, attitudes or behaviour. Unfortunately knowledge from a systematic review such as this one does not help in the evaluation of the effectiveness of sex education programmes in developing countries, where there may be no other formal sex education in place such as in segments of Belize. Studies conducted to determine which types of programmes are most effective as well as methods to improve these programmes are still needed. By evaluating programmes in populations that differ by ethnicity, socio-demographics, and other factors, we may be better able to deliver tailored and therefore more effective sex education.
Five RCT evaluating sex education programmes have been conducted in developing countries; these were not included in the most recently published systematic review. All five RCT demonstrated an increase in knowledge following the educational programme.16,22,24,25,37 Of the four studies measuring change in attitudes, two showed increases in positive attitudes.24,37 Of the three studies measuring behavioural intent only one showed a positive change.25 Four of these studies were randomized by cluster;16,24,25,37 yet only one took into account the clustered nature of the data upon analysis.37 This study, conducted in the Philippines, found improved knowledge and attitudes about AIDS following the intervention. Only one of the five RCT was conducted in a region that may share some ethnic and socio-demographic similarities with Belize. This study was conducted in Nicaragua, Central America and also found improved knowledge following a sex education programme. However, this was not an evaluation of a school-based programme but instead a programme for adults accrued from their homes.16 Also this study randomized only two clusters to each arm and significant differences existed between the two arms on level of education at baseline.
The current evaluation of the RSP expands upon a previous evaluation of the RSP conducted in Canada using a quasi-experimental design and enrolling 64 students.38 This previous study also showed a significant improvement in knowledge after the programme (P < 0.01), but only for females. The Canadian study also found the RSP improved attitudes for females (P < 0.05) and fostered safer behavioural intent for both males and females (P < 0.05). However, this study was quasi-experimental and did not use appropriate statistical techniques for its clustered design.
The most recent systematic review of RCT of adolescent sex education programmes calls for future research into programmes developed from suggestions made by young people that emphasize negotiation skills in sexual relationships and communication, as the RSP does.17 Therefore the current evaluation of the RSP is an important one. It is contributing sequentially to a large previous literature on sex education programmes by providing an evaluation of a programme which emphasizes components believed to be important and by conducting the evaluation in Belize, a developing country where no previous literature exists on effectiveness of sex education programmes in area schools. The RSP received positive feedback from students, teachers, principals, and government officials and increased knowledge after the programme. Results from this study and other similar studies may be used to further improve the RSP and other sex education programmes.
Future research in this area should include studies that aim to improve instruments to measure knowledge, attitudes, and behavioural intent. Research should also focus on developing an appropriate causal model for responsible sexuality and to examine within, the relative effects of knowledge, attitudes, and behavioural intent on behaviour change. Inclusion of covariates into the causal model would also supplement our understanding of the role of sex education and may increase our understanding of the effectiveness of sex education for particular sub-groups.
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