Adolescence is a period of rapid physical, emotional and psychological changes which renders adolescents vulnerable to risky behaviours such as early sexual activity. Initiation to sexual activity by adolescents poses a major problem to both social and public health, especially in developing countries like Cameroon [1]. According to WHO, early sexual activity is defined as having had sex before the age of 15 years [2]; meanwhile, the perceived right age for sexual debut varies from one individual to another and across societies [3]. In Cameroon, Meguieze et al. reported a mean age at sexual initiation around 15.5 years [4]. A study in the Netherlands revealed that adolescents exposed to electronic devices such as televisions, telephones, and computers were significantly more likely to engage in early sexual intercourse [2]. Gazendam et al. in Canada noted that among early-aged sexually active adolescents (12 or 13 years), the proportion of boys exceeded that of girls with factors such as family structure, physical activity, social media use, and perception of family affluence being correlated with early sexual activity for both males and females [5]. In West Africa, factors associated with early sexuality were found to be male gender, intake of alcohol, and having friends who engaged in sex [6]. Conversely, in East African studies, factors found to predict early sexuality were parents’ educational level, sex, place of residence, and exposure to pornography amongst others [7].

Despite the significance of early sexual activity among adolescents, there is a need for a more nuanced understanding of the determinants of early sexual activity among adolescents in Yaoundé, considering the local context and cultural nuances. This study therefore aims to investigate the determinants of early sexual activity among adolescents in Yaoundé.

We consecutively recruited 904 students in our study, of which 818 were included and 41 were excluded for a sample size of 777.

Early sexual activity is a global public health problem. There is a worldwide rapidly increasing frequency of youths indulging in sex. This rise is associated with a negative impact on students’ health, as well as their future professional and social lives. For this reason, we carried out a cross-sectional study in nine secondary schools in Yaoundé to assess the factors associated with early sexual activity among adolescents. The sexual practices considered in this study were oral sex, vaginal or anal penetration, and masturbation.

A total of 908 students were enrolled in this study with 777 students meeting our inclusion criteria. The overall occurrence of sexual activity among adolescents in this study was 57.66%. This result was higher than what was reported by Foumane etal. among female adolescents in Yaoundé, Cameroon in 2013 [8]. This could be explained by the sexes of participants in our study. Indeed, we recruited both female and male participants to have a general view of adolescent sexuality in Yaoundé. Our finding suggests that more and more adolescents engage in sexual activity.

Most of the participants were older than 15 years with a mean age of 16.37 ± 1.54 years. This result is similar to those published in 2018 by Girmay etal. in northern Ethiopia, which reported an average of 16.3 years [7]. This similarity could be due to the nature of the participants who were adolescents in secondary school settings.

In our study, 61.9% of the participants were female. This value is slightly higher than values (57.7%) obtained by Millanzi etal. among adolescents in Tanzania in 2023 [9]. This rise may be due to the higher sample size in our study and the different geographical locations. However, according to WHO adolescent’s population in Cameroon in 2023, there are more male adolescent than females.

Concerning the religiousness of the study population, 89.6% were of Christian faith. With 50.3% reporting to be living with both parents at the time of the study. A similar study in Ido-ekiti and Ekiti state Nigeria conducted by Durowade etal. in 2017 to determine the prevalence and risk factor of early sexual debut among adolescents in secondary school obtained a slightly lower rate of Christian faith (88.5%) and 64.7% of participants living with both parents [6]. This finding may have to do with the differences in total surface land areas and rural nature of these states in Nigeria. While commitment to a religion is associated with more restrictions sexually, religion do not appear to influence sexual behaviour uniquely [10].

The mean age of first sexual onset was 15.46 ± 1.47 years, with most participants (71.9%) aged ≥ 15 years at first intercourse. The occurrence of ESI in our study was 28.12%. These findings are like values reported in Cameroon by Eboutou etal. in 2023 [11]. In their study, the mean age of ESI was 15.54 years while the prevalence of ESI was 26.37%. Early sexual initiation may be attributed to rapid urbanization, access to new communication techniques and changes in social norms which arouse adolescent’s curiosity and thus expose them to ESI [12]. In general, adolescence is a time of major risk for ESI marked by interest in sexuality during early adolescence, self-exploration of this sexual interest and relationships during middle adolescence. Nonetheless, studies have shown that age at first sexual experience varies from place to place and among different individuals usually due to different factors.

In our study, 99.6% of participants consented at the first sexual intercourse. In most cases, the sexual partner was described as a boy/girlfriend (75.9%). This finding is higher than that of Meguieze etal. [4] who obtained a consent rate of 84.1% and slightly lower rate (69.7%) of sexual partners described as boyfriend/girlfriend.

Most of the first sexual acts occurred during holiday periods at 51.1%. This finding is opposite to the findings reported by Essiben et al. in Cameroon in 2019 [13]. They reported that 82.3% of adolescents were sexually active during academic year periods. This discrepancy could be attributed to the difference in sampling methods and sample sizes. We can assume that educational environment creates opportunities for adolescents to network among themselves and make decisions pertaining to sexuality among others [10]. However, periods of ongoing classes are not idle as compared to holidays periods.

Licit drug use at first sexual intercourse was present in only 10.5% of cases. This finding was similar (13.4%) to that of James et al. who sought to investigate the sexual risk behaviors among school going adolescents in Sierra Leone in 2022 [14]. This is possibly so because intake of alcohol especially if excessive can cause loss of self-control.

In 79.5% of cases, sexual intercourse at initiation was protected with use of condom. A study carried out by Gravningen et al. to study early sexual behavior and Chlamydia infection among Norway adolescents reported 57.8% of contraceptive use at sexual initiation [12]. This increased difference in our study could be attributed to the fact that most adolescents in our survey reported having planned (62.3%) the sexual act and probably because male condoms are easier to purchase and more accessible. However, Girma etal. reported to have 31.7% planned sexual act among adolescents in Addis Ababa in Ethiopia in 2018 [13]. This difference could be explained by the type of schools considered in our survey (74.2% private school’s) versus 100% government school in Ethiopia.

In our survey, participants reported love for partner (86.8%) and pressure from group of friends (10.7%) as the motivation to engage in first sexual activity. Whereas other studies in Ethiopia, Nigatu etal. reported pressure from group of friends (peer pressure) at 52.8% while Girma etal. reported love for partner in only 24.8% of cases in 2018 [13][14].

This study found out that gender was significantly associated with early sexual debut. The male gender significantly increased the risk of early sexual debut among adolescents by 2 (p < 0.001). This result is in line with the study conducted in Cameroon in 2022 by Meguieze etal. and in Nigeria by Durowade etal. in 2017 [4][6]. This could be due to the fact that males have lower levels of impulse control, higher levels of sensation seeking, more adventurous, and desirous than female counterparts [15].

Children attending state schools were more at risk of early sexual initiation. This suggests that public schools are critical setting for adressing sexuality in teenagers. It indicates a failure in strategies to implement appropriate sex education, promote open communication and create inclusive, non judgemental support for adolescents [16].

Trans identity increased the risk of sexuality in our study population by 3 (p = 0.001) [17]. However, in 2017 in the United States according to Eisenberg & al relative to cisgendered youths their trans counterparts were more likely to have early sexual debut [18]. Similar results were obtained by Kattari etal. in 2019 [19].

In our study population, adolescents of Christian faith [OR = 0.83 (0.46 - 1.51)] seemed to be protected from ESI. A study in Ghana by Kyei-Arthur F etal. in 2024 reported that Muslims and other categories of religions were more vulnerable to early sexual activity compared to those of Christian faith [20].

Adolescents who reported using licit drugs (OR: 2.40; p < 0.001) as well as illegal drugs (OR: 2.91; p < 0.001) respectively were more likely to engage in ESI. This fining is similar to Durowade etal. and Omona & Ssuka in Uganda in 2023 [6][21]. The impaired effects of these drugs on the decision-making of adolescents could explain this result.

In our survey, adolescents who reported masturbation (OR: 1.95; p = 0.001) and going to nightclubs (OR: 4.32; p < 0.001) were more exposed to early sexual debut. Exposure to online sexual content such as pornography leads to the desire to experience sex which is primarily sought through masturbation and later in the sexual act properly. This explains our finding which was similar to that reported by Millanzi etal. in Tanzania in 2023 [9].

Adolescents from single-parent family type [OR = 1.29 (0.95 - 2.06); p = 0.055] were close to significance to be more predisposed to indulge in early sexual intercourse. This is coherent with results obtained by Furlanetto etal. in Brazil and Gazendam etal. in Canada in 2019 [5][22]. Perhaps adolescents from disrupted families experience less parental supervision, also, adolescents without close family ties may seek it in sexual relationships [23][24].

In our study, those whose parents attained tertiary level of education [OR 0.65; p = 0.019] had a lower risk of early sexuality. According to White & Warner in 2015 mean parental educational attainment moderates the influence of adolescent’s attitudes towards sex [25]. Likewise, Guetto etal. reported in 2022 that higher parental education is associated with higher likelihood of protected first sexual intercourse for their adolescent children while lower parental education exposes adolescents to ESI and risky sexual behavior [26].

We found that having a sexually active company (OR: 4.57; p < 0.001) increased the risk of early sexual debut among adolescents in Yaoundé. This is similar to the report of Millanzi etal. in Tanzania who reported that exposure to a group of friends favours sexual decision making [6]. Indeed, adolescence is a period where youths seek reward and feeling of belonging especially to a social group.

Receiving sexual education from parents, tutors and care takers reduced the risk of early sexual debut (OR 0.54; p = 0.002) among adolescents in Yaoundé. A study carried by Klu etal. in Ghana in 2022 reported that the degree of communication on sexual issues between adolescents and their parent’s affects adolescent sexual decision making in a directly proportional manner [27].

Even though socioeconomic status is known as a key determinant of health behaviors, like psychoactive drugs initiation in teenagers, no association was found beween weekly allowance and early sexual debut in this cohort [28].

The lifetime prevalence of early sexual onset is high, making it a public health problem as more and more adolescents engage in sexual activity. Most students started early sexual activity during middle adolescence with opposite sex partners. The most commonly descriptive criteria of the sexual act initiation were sex occurring during holidays periods, sex was with boy/girlfriend and protected sex. Motivation was pleasure out of love for partner and peer pressure. Individual and community factors such as sex, age, religiousness, group friends, type of household, parental level of education, and licit drug consumption were the strongest determinants of early sex among adolescents.