![[ Visit Client Website ]](images/banner.gif)
Choosing from a variety of HIV prevention offers or developing new offers presupposes a comprehensive understanding of the dynamics an intervention should impact on. Therefore, the further development of explanatory models of HIV protective behavior continues to be relevant.
The IMB model is one of the best-performing explanatory models of condom use. Preventive interventions drawing on the model proved effective. However, the (traditional) IMB Model includes merely socio-cognitive constructs. An extended IMB Model developed in Europe complements the variables of the traditional IBM model with variables referring to cultural, social and economic resources. Further it includes situational- and partner-related inhibitors of condom use. Given this alternative, this project aimed to establish whether the explanatory power of the extended IMB model exceeds that of the traditional IMB model. Given the need for knowledge about condom use in Central America, this question was tested on a Costa Rican population.
The guiding research questions were: (1) Can the traditional IMB model be confirmed in explaining condom use among Costa Rican young adults aged 18-24? (2) Does the explanatory power of the extended IMB model prove to be stronger than that of the traditional model?
Methods
A stratified random sample of young women and men aged 18–24 living in Costa Rica was drawn. Data were collected using standardized personal interviews. Data were analyzed using descriptive statistics and the model tested by means of structural equation modelling using the scale-free least square method.
Results
The sample of 905 young adults aged 18 to 24 comprised 484 women und 419 men, of which 349 reported having had sex with a casual partner in the last six months. Of the 314 respondents who had vaginal sex, 26.4% reported having used a condom consistently (every time).
Testing the traditional IMB Model confirmed that behavioral skills (condom self-efficacy), knowledge, and attitudes were predictors of condom use. Behavioral skills were also predicted by knowledge and attitudes and additionally by the subjective norm and perceived susceptibility.
Testing the extended IMB Model confirmed the adoption of a personal HIV protection strategy, which implies condom use and economic resources as additional predictors of condom use. Further predictors were trusting one’s partner, not having a condom to hand during the sex act, and the use of alcohol or recreational drugs before or during the sexual encounter. The social-cognitive predictors in play turned out to be determined by cultural and social resources such as the educational level and peer incentives. Comparison showed that the explanatory power of the extended IMB Model (adj.R2=0.19) exceeded that of the traditional model (adj.R2=.10).
Conclusions
The extended IMB model proved to have greater explanatory power than the traditional IMB model. We suggest that the extended model be tested in further research. For social work the challenge will be to develop prevention offers considering the determinants suggested by the extended model. Now that international stakeholders want prevention to concentrate on “key populations” only, the development of up to date interventions for (heterosexual) youth becomes a challenging endeavor.