[Sociodemographic variables and risk behaviours for HIV infection and sexually transmitted diseases in adolescents: Spain, 2007].

BACKGROUND The development of HIV and STD prevention programs needs information about sexual behaviour. The aim of this study is to analyze whether there were differences in HIV/STD risk behaviours according to type of high school (public/private), gender and age in adolescents. METHODS A representative sample of 4.456 adolescents participated. To select the participants, a stratified random sampling considering Spanish regions and type of high school was used. It is a cross-sectional survey study. RESULTS The percentage of adolescents that did not use condoms at first sexual intercourse was higher in private than in public high schools (chi(2) (1)=5,06; p=0,02). Adolescents who were between 17 and 18 years old had the highest percentage of non condom use at last sexual intercourse (chi(2) (2)= 6,90; p=0,03). A higher percentage of males than females had a casual partner at last sexual intercourse (chi(2) (1)=127,79; p=0,00). A higher number of adolescents of private high schools than adolescents of public high schools had used drugs at last sexual intercourse (chi(2) (1)=5,72; p=0,02), as well as males compared to females (chi(2) (1)=36,37; p=0,00). CONCLUSIONS Differences in HIV risk behaviours according to sociodemographic variables are shown. Therefore, taking into account sociodemographic factors in sexual education programs focused on adolescents seems to be necessary.