Studies on sexual behaviour from Central and Eastern Europe (CEE) are scarce. The lack of information on sexual behaviour is most salient regarding late adolescence and young adulthood, when young people start to live without direct parental supervision. The best recent information available is based on the Health Behaviour in School-aged Children (HBSC) studies 2001/2002 and 2005/2006 [1]. In both studies (Slovakia is not included in the first one) adolescents from Central and Eastern Europe reported that they were less experienced with sexual intercourse, used contraception pills or condoms during their most recent sexual intercourse to a lesser degree and initiated sexual intercourse later in life than their peers from most Western countries. However, patterns in the sexual behaviour of adolescents and young adults in Central and Eastern Europe seem to be changing. A decrease in the age at which they become sexually active is evident, particularly among females, leading to a narrowing of the gap between boys and girls regarding the time of sexual initiation.

In the context of sexually-transmitted infections (STI), many studies show the inconsistent use of prophylactic methods (e.g. condoms) to be the main risk factor [2–4]. However, early sexual intercourse, having multiple sexual partners and the association with substance use should also be considered as significant risk factors in this age group. Although each of these factors can be considered as an aspect of risk-taking, none by itself is valid as an operationalisation of risk behaviour [5, 6]; yet all have become important topics in health promotion.

The association of sexual risk behaviour (SRB) with a number of other risk behaviours, including substance use, is evident. Use of marijuana, cocaine or other illicit drugs by adolescents has been shown to be associated with increased rates of sexual intercourse in general, having multiple sexual partners and lower rates of condom use, particularly for users of illicit stimulant drugs [7]. Binge-drinking teens are approximately three times less likely to use condoms, and recent marijuana users are almost two times less likely to use condoms [8]. The increasing prevalence of alcohol, drugs and tobacco use among Slovak adolescents as reported in the ESPAD (European School Survey Project on Alcohol and Other Drugs) reports of 1995, 1999, 2003, 2007, [9–12] and the lack of scientific studies in this field in CEE countries led us to explore the association among this behaviour and sexual risk behaviour.

Early sexual initiation is related to multiple aspects of SRB, including inconsistent condom use, early pregnancy and a greater number of sexual partners [13, 14]. Moreover, it is also a predictor of future gynaecological problems. Girls who reported having sexual intercourse before age 16 had significantly more symptoms such as vaginal discharge and pruritus and signs such as abnormal discharge, erythema of the vaginal mucosa and lower genital tract infections than girls who first experienced sexual intercourse after age 19 [15]. It was found that 81% of sexually experienced youth aged 12–14 wished they had waited longer to have sex, compared with 55% of sexually experienced 15 to 19-year-olds [16]. Because of this we expect higher levels of SRB among those who report early sexual initiation.

SRB and other health-endangering behaviours may be considered the result of a number of determinants, which range from causal factors very close to the behaviour like attitudes and perceived social norms [17, 18] to more distant causal factors like personality,[14, 19, 20] or even socioeconomic position [21]. As such, they may have shared causes with problem behaviour, as suggested by Jessor [17, 18]. Thus, we might expect, for example, a co-occurrence with other problem behaviours,[7, 22] or with psychological factors.

A study by Reitman [20] which explored the role of self-efficacy and self-esteem found that adolescents who believe they could take "effective precautionary action to avoid HIV" had fewer sexual partners and reported more condom use than peers who had lower self-efficacy scores [20]. Low self-esteem has also been associated with inconsistent use of contraceptives among adolescent girls [14]. Various indicators of psychosocial distress, which frequently occur along with low self-esteem, have been found to be associated with more frequent sexual activity [23–26]. Furthermore, several studies included religiousness among the factors associated with SRB, although the results from these studies are not consistent.

Summing up, the aim of our study was to explore the association of behavioural (drinking, smoking, early sexual intercourse) as well as psychological factors (self-esteem, psychological well-being, extroversion, neuroticism, religiousness) with three aspects of SRB: (1) sexual intercourse under risky conditions, (2) multiple sexual partners and (3) inconsistent condom use among late adolescents.

This study on SRB in young adults in CEE shows that the occurrence of SRB in Slovak young adults varies from 21 to 81% of sexually experienced respondents (n = 455), depending on the indicator used. The most frequently reported SRB is inconsistent condom use, despite the fact that consistent condom use is one of the most efficient ways of protection. The occurrence of sexual intercourse under risky conditions is also very high, varying between 33–44% of the sexually experienced. From 5 to 9% of respondents reported having already had sex before age 16, and 27% of males and 21% of females reported having had multiple sexual partners.

From an international point of view, Slovak students have their sexual initiation exceptionally late, and the number of their sexual partners is low. On the other hand, similar to other studies, no gender differences were found in the prevalence of having sex. These findings fit with those from the HBSC study, where a lower proportion of sexually experienced individuals was reported among 14 and 15 years old adolescents in Central European countries (Hungary, Czech Republic, Croatia, Poland) compared with adolescents from Western or Northern European countries [1].

In line with several other studies [37–40], our study shows that alcohol use is one of the most consistent predictors of SRB. This finding supports the explanations that less self-control leads to risk behaviour and that certain people have a psychological predisposition to seek sensation and are thus more likely than others to engage in a variety of risk behaviours [41]. However, without contextual information about this event, we cannot clearly state that alcohol or drug use has a causal relation to SRB. It should be noted that our measurement of having sex under risky conditions covers lifetime history, which might be the reason for the high proportion, but on the other hand, lifetime history in this age group represents only about 4 years of life. Future analyses should go more deeply into the dimensions of a relationship like trust, intimacy, commitment and communication and their effect on behaviour. Our approach is important especially among the young population, where the age of the first contact with alcohol consumption is rapidly dropping [1].

The study results also revealed relevant differences between male and female sexual behaviour. Males report mostly behavioural factors as significant predictors for sex under risky conditions and multiple sexual partners. On the other hand, females add psychological factors. Their lower levels of extroversion and higher levels of religiousness are associated with fewer sexual partners, in accordance with other studies [42, 43], where religiousness seems to be a protective factor against a high number of sexual partners among girls. On the border of statistical significance was the association between a high level of religiousness and a low probability of having sex under risky conditions. Thus, it is probably not only religiousness that plays an important role. Several studies have shown that girls who report a high importance of religiousness probably live in such psychosocial and cultural environments (personality, relationships, family, friends, and school) that opportunities for SRB are rather limited [44, 45]. On the other hand religiousness had no significant association with sex under risky conditions or inconsistent condom use, which suggests that among those who have already had sexual intercourse, religiousness does not play a role. We can conclude, then, that despite the high importance of religiousness among students, their sexual behaviour reflects strategies more risky than safe.

Inconsistent condom use has been frequently reported as a major pattern of SRB. Only those who reported consistent condom use were defined as a safe group; all others were defined as a risk group. This strict criterion comes from the assumption that each intercourse without a condom is risky in terms of STI infection or unintended pregnancy. Of course, such a definition cannot be used in each age group, but among first year university students, 90% of whom are in the 19–23 age range and where it is difficult to expect stable and long lasting sexual partnerships or unprotected intercourse with the aim of becoming pregnant, this methodical criterion should fit. Despite the high rates of inconsistent condom use in our sample (72.4% of males and 80.7% of females), we only found an association with drinking in males and smoking in females. These results are in accordance with previous research [8, 46, 47], which showed alcohol consumption to be negatively associated with condom use. Nevertheless, recent studies have recognized the importance of examining how sexual relationships themselves influence condom use. It is possible that alcohol only has an effect on condom use at specific phases in a relationship [48].

Studies which explored the role of alcohol use on condom use [49–51] and studies which assessed the length of a relationship [52] or the type of relationship [53] did not find any association between alcohol consumption and condom use. Moreover, these results do not support the persistent notion that alcohol causes people to engage in sexual risk that they would avoid when sober. Instead, people tend to follow their usual pattern of condom use, regardless of alcohol use [50]. Such inconsistent findings regarding condom use and drinking suggest the possible effect of a third factor which affects both variances, and that any relationship between condom use and drinking is disputable. Mental health problems, developmental factors, disposition to risk taking and sensation seeking, familial influences and general tolerance for deviance have all been reported as possible third variances in literature sources [54–57]. Consequently, an association between alcohol use and condom use could be attributable to these factors and not to any relationship between alcohol and condom use [48]. Nevertheless, our results suggest that behavioural factors are more closely related to SRB than psychological ones.

The overall findings of our study suggest that the specification of SRB into three indicators contributes to a better understanding and description of SRB. All three indicators provide a specific and different view on adolescent sexual behaviour. Consequently, several significant differences were found between the indicators, which suggest an important variance in SRB and allows several recommendations to be formulated. Systematic prevention should be focused on the high incidence of sexual risk behaviour among young people, which indicates the need for health promotion programmes not only on smoking, alcohol and drugs, for example, but that sexual risk behaviour should also be integrated into prevention programmes. Due to the accumulation of risk behaviour among young people, focusing on prevention in a related set of unhealthy behaviours instead of a single type of unhealthy behaviour will be very important, particularly in early adolescence. Moreover, results show a high need for health promotion programmes in early adolescence that target SRB in conjunction with other health-related risk behaviours such as alcohol abuse.