In traditional African narrative, substance use by youths was never a practice in which socialization envisaged. Therefore, socialization did not provide for the containment of that moral issue. Trendy alternative lifestyles that African youth freely access online and on other electronic media have predisposed the current generation of youth to substance abuse. The law as a colonial heritage defines the act of substance abuse by youth as a status offence. While sex was traditionally held as a practice reserved primarily for procreation, its excitement-satisfying function was an imported value into Africa. Therefore, the implications of substance abuse and sexual frequency for sexually transmitted infections among Nigerian youths are extensive in the West just as they are among adolescents in Macau (1), and probably in Nigeria. In Nigeria, substance use is one of the key factors that predispose young people to sexually frequent behaviours. Therefore, substance use and sexual frequency have considerable economic and substantial public health implications for Nigeria. Moreover, in the West, studies have shown that a strong relationship exists between substance abuse and risky sexual behaviour among adolescents (2).

Sufficient western research evidence supports the likelihood that substance abuse may influence adolescent sexual behaviour (3). The associations between substance use and sexual behaviour are complicated, with empirical causal evidence for the relationships in both directions, and for mutual reasons of both behaviours, contingent on the environment and residents (4; 5; 6). Among youths, the extraordinary frequency of harmful substance use, thrillseeking, and sensation-seeking actions causes difficulty in measuring the causal elements of frequently detected connotations between substances and sexual consequences (4; 7; 8). Among the likely negative outcomes of heavy substance consumption for sexual health among youths are those previously singled out in younger people, such as STIs, unwanted pregnancies, and lamented sexual involvements (9). In this article, our objective is to examine the role of substance abuse in sexual frequency and outcomes among Nigerian youths.

In the first study to examine the association between substance use and frequency of sexual intercourse in the United States at the population level, Eisenberg (10) observed that substance use, specifically marijuana use is very widespread. But he added that its significant use and association with sexual frequency had not been considerably studied scientifically. To the extent that Nigeria uses an admixture of Western and traditional African values to socialize her youths and only a little research attention has been given to the impact of substance abuse and sexual frequency on STIs among Nigerian youths so socialized, this investigation cannot be more timely. Research studies conducted in the West indicate a strong relationship between substance abuse and risky sexual behaviour among young people (11). Whereas risky sexual behaviour emphases adverse health aspects, such as sexually transmitted diseases, relatively little research attention about the sexual misconduct of young people exist in Nigerian communities. The influence of peers on adolescents is significant. Research has indicated that it is inborn for humans to interact with compatible individuals (12, 13). However, empirical evidence supports the claim that a peer group exerts a substantial influence on decision making regarding sexual activities (14, 15).

Generally, empirical findings on the relationship between substance abuse and risky sexual behaviour are inconclusive. On the one hand, researchers stated that substance abuse leads to risky sexual behaviour owing to the disinhibition effect (11, 16), some researchers claimed that risky sexual behaviour leads to substance abuse (4) on the other. Studies on deviant behaviour in the area of substance abuse by young people have revealed that it is associated with having generous sexual sentiments or being sexually active (17, 18). Earlier studies have also indicated that substance abuse plays a role that positively correlates with involvement in risky sexual behaviour among younger people (19, 20, 21, 22, 23). Although numerous studies have socially observed the associations between substance use and sexual frequency in the course of adolescence, few of any degree has been conducted in Nigeria. In this connection, research is required to increase the understanding of the scientific community about what shapes sexual frequency, particularly the role of substance abuse, and their consequences to send critical signals to policymakers for necessary and effective interventions.

It is in this regard that the present study answers the following questions. (i). Does substance abuse influence sexual frequency among youth in Nigeria? (ii). Is there any relationship between substance abuse and the transmission of STIs in Nigeria? (iii). What is the relationship between substance abuse and the use of condoms among youth in Nigeria? (iv). Does substance abuse influence sexual risks among youth in Nigeria? The present study used the data collected from a large sample of Nigerian youths in 2012 to fill the gaps in youth substance abuse and sexual frequency. We, therefore, hypothesize that (i). Substance abuse might be the crucial factor triggering sexual frequency among youths in Nigeria. (ii). There is a significant relationship between substance abuse and STIs transmission and (iii). Substance abuse may likely influence sexual risks (having multiple partners, non-use of condoms during sexual intercourse, having concurrent partners, contacting STIs) youth in the study area.

The data analysis employed Stata14.0 software. The data for the study were analyzed using three levels of statistical analysis, univariate to show the frequency distributions of the socio-demographic characteristics of the respondents’, proximate variables and explanatory variables comparing substance users with non-users. The Bivariate analysis was used to show the differentials in the socio-economic characteristics of the respondents and the use of substance among young never married in the study area. For multivariate analysis, two statistical techniques were used and five models were constructed to test the formulated hypotheses. These models were also adjusted with proximate variables (see Table 1) Binary logistic regression was used to show the relationship between outcome variables which can be dichotomized (HIV test result and risky sexual behaviours i.e. non-use of condom during sex and having multiple sexual partners) and independent variable (substance abuse). While Poisson regression was used to estimate the incidence of relative risk (IRR) of substance abuse (smoking cigarettes and drinking alcohol every day) and sexual frequency (count data).

Table 2 reveals the selected characteristics of the respondents, from the study it was observed that majority of the respondents are between aged 20-24years while 71.73% were males. More than twothirds of the respondents had secondary education at the same time 72.39% are non-Catholic Christians. Whereas forty-three percent of the respondents indicated that they had been away from home for more than one month in the last twelve months preceding the survey. The sexualbehaviour of the respondents depicts that 56.45% had sexual intercourse 12 months preceding the survey while 36% had two or more sexual partners. Regarding condom use, half of the respondents ever used condoms while 3.30% among those tested are HIV/AIDS positive. Among the sampled population, nearly 71% consumed alcohol every day while 10.07% are currently smoking cigarettes and other substances such as Cocaine, Heroin, and Marijuana.

Table 3 shows the percentage distribution of selected characteristics of the respondents and substance abuse, it is pertinent to note that males are the highest substance abusers (Drinking Alcohol everyday male 73.36% female 26.64% 2 P-value = .000, Smoking cigarette male 91.5%, female 8.49 2 P-value =.000) in the study area same as those in aged 20-24years (consuming Alcohol everyday 20-24years 55.96% 15-19years 33.94% 2 P-value = .097, Smoking cigarette 20-24years 55.96% 15-19 years 33.94% 2 P-value = .006). The significant relationship was also established between religion, use of condoms, age at first sex, and smoking (2 Pvalue <.001) while those who are away from home for more than one month have a significant likelihood of drinking alcohol every day (2 P-value= .005).

The logistic regression of substance abuse and risky sexual behaviours in Table 4, pointed out the higher significant relationship between having multiple partners and substance abuse with the unadjusted data (P-value <.001). When the data was adjusted with the confound variables the significant effect of the smoking cigarette with having multiple partners was revalidated (adjusted data Smoking cigarette odds ratio 2.50, P-value <.001). In the same vein, a significant relationship was established between smoking and non-use of condoms in the study area even when the data was adjusted with confound variables (unadjusted data smoking 3.74 P-value <.001 adjusted data smoking 2.57 P-value <.001).

In model three, the poison regression validated the significant relationship between substance abuse and sexual frequency for both adjusted and unadjusted data in the study (P-value <.001) (Table 5). It is also noteworthy that the higher significant effect of drinking alcohol every day and sexual frequency was affirmed when compared with the reference category those who drink occasionally or seldom (unadjusted data odds ratio 1.07 P-value <.001, adjusted data odds ratio 1.40 P-value <.001).

The logistic regression of substance abuse, sexual frequency, and HIV in Table 6 shows a higher significant effect of consuming alcohol every day with the likelihood of having HIV in the study area. When the sexual frequency was added to the model, the significant impact of smoking and sexual frequency was reaffirmed with the likelihood of having HIV in the study area (P-value <.001). In the same context, when the data was adjusted with the confound variables, smoking was significant with the likelihood of having HIV (P-value <.001). While the higher significant effect of sexual frequency on the likelihood of having HIV was enacted in the study (adjusted data odds ratio 9.73 P-value <.001).

The study has reaffirmed the relationship between substance abuse, sexual frequency, and STIs in Nigeria. It was observed in the study that the majority of those who are involving in substance abuse had secondary education. Studies have established a significant association between formal educational attainment and range of individual health outcomes and risks such as drinking alcohol, smoking cigarette, and other substances (3, 4). Illicit substance abuse may hinder the opportunity for scholarship and other forms of financing higher education thereby constrained the abusers not to further their education beyond the secondary school level (33). Substance abuse may simply decrease academic performance, shifting individual resources from schooling to substance use, and lead to higher failure and increase drop-out rates. In a study in Nigeria among students and out of school youths in urban areas, a positive relationship was observed between substance abuse in the early stage of life and risk of early school dropout in addition to involvement in deviant adolescent behaviours (34). Similarly, the significant relationship established between age at first sexual intercourse and smoking among the respondents aligned with the previous researches (2,7).

A Survey conducted in the United States of America found out that more than five million adolescents have unprotected sex at an early age because of alcohol and drug use. Substance abuse normally acts as a gateway for risky behaviour such as having sexual intercourse at an early age. Since the purpose of drinking alcohol or smoking of cigarette and other substances among adolescents varies, some for sensation seeking and desire for hallucination especially in developed countries while in developing countries alcohol abuse is strongly seen as a means of tension relief and coping mechanisms to reduce emotional problems (35, 36). Risky behaviour can be exhibited under the influence of substance intoxication, in some instances alcohol is seen as a facilitator of sexual encounter and maleness, enhancer of sexual experience, and an excuse for irresponsible behaviour. A study conducted in eight countries on alcohol and sexual behaviour reports that respondents believed that alcohol facilitated or enhanced sexual intercourse, reduce fears connected to sex, provide extra power for sex, delayed orgasm, decreased sexual inhibition and help to build the courage to approach a possible sexual contact (37).

The significant association between substance abuse and risky sexual behaviour (having multiple sexual partners and non-use of condoms during sexual contacts) was also validated in the study. Substance abuse may increase the likelihood of youth engaging in risky sexual behaviour with the tendency of contracting STIs. A study in Ethiopia found out that more than two-thirds of the street children who are abusers of substances did not protect themselves during their last sexual intercourse despite the fact that they also have multiple partners (38). A similar study conducted in South Africa among the street youth pointed out that the need for economic sustenance led the youth to risk-taking such as inability to obtain condoms, having multiple sex partners, and taking of drugs (39). Reasons for not using condoms among the street youth include; it decreases sexual pleasure and difficulty in using condoms during the heat period (38). In the same vein, a study in Ghana documented that smoking, Tawa use, tobacco use; drunkenness, marijuana use, and other drug use were all associated with sexual debut and number of sexual partners. It was also noted that substance abuse independently increases the chances of having multiple partners, those who use substances have 8 to 16 folds of chances of having multiple sex partners when compared with non-users (40). While among females transactional sex was a strong factor for having multiple sex partners and non-use of condoms during the sexual debut.

Furthermore, a study among the homeless youth in Ghana revealed that 54% of the sampled population had sold their body for food, money and even a place to sleep, with females more likely to engage in such behaviours than males. At the same time, age at first intercourse was positively related to having multiple sexual partners with low condoms use among adolescents using substances (41). On the other hand, it was reported that respondents who had a greater number of sexual encounters under the influence of alcohol were more likely to use condoms than others since drinking often takes place in settings where potential sexual partners are available (42). Study in India reveals that those youth with higher education are more risk averters in terms of condoms use than lesseducated youth despite consuming alcohol before sex (43). In addition, the higher significant effect of drinking alcohol every day on sexual frequency observed in the study consolidated the earlier findings of substance abuse and sexual frequency (42, 11).

Study in America reported that those who drink alcohol regularly have the likelihood of having multiple sexual partners; this is to satisfy the increased sexual libido. It was also reported that the sexual frequency of the respondent under the influence of alcohol was positively associated with condoms use (44). An increase in the use of substances may likely increase the number of sexual encounters and as well as engaging in risky behaviour such as non-use of condoms and having multiple sexual partners. A study found marijuana use to be positively related to increased sexual frequency (45, 46). The complexity of the impact of substance use on sexual activity was also noted in some literature (46, 47, 48) while the use of cocaine has been found to delay orgasm, enhance sexual pleasure, increase frequency of sex, and arousal. On the other hand it is also associated with erectile dysfunction, diminishes sexual desire, and hampers orgasm (47, 48). Nevertheless, the significant relationship between substance abuse, sexual frequency, and STIs is evident in this study. Studies have pointed out that less knowledgeable youth who consumed alcohol has a likelihood of contracting HIV and STDs (39). Alcohol consumption is not only an originator of risky sex but also as an outcome of it.

A cross-sectional analysis of alcohol and drug use during sexual activity and compliance with safe sex guidelines for AIDS showed that use of drugs or substances during sex, the number of drugs used during such activity, and the frequency of combining drugs and sex are all positively related with risky sexual activity for AIDS (49). The factors responsible for the interaction between alcohol use and sexual behaviour that posed risks for STI/HIV infection include the construction of manliness in terms of alcohol use; a denial and neglect of risk as a way of coping with life; the use of alcohol-serving venues as contact places for sexual encounters; the use of alcohol at/during (first) sexual encounters; and the promotion of alcohol use in pornographic material (37). Study in Ghana shows the vulnerability of youths to HIV/AIDS as a result of high levels of sexual risk behaviour (multiple sexual partners, involvement in survival sex, and irregular condoms use) in contexts of high alcohol and drug use (40). On the other hand, HIV risk behaviour among youth normally influenced by interpersonal processes such as peer group norms, perceived gender roles, lack of communication skills to negotiate condoms use, and their understanding of love, sex, and relationships. The positive influence of peer pressure on substance and drug use, likelihood to become sexually active at an early age, have more sexual partners and probability to practice unsafe sex with the implication of contracting HIV has been established (50,51).

Above all, the 2.9% prevalence rate of HIV/AIDS among the selected sample size is a confirmation that HIV/AIDS are more common among high-risk groups such as the mobile population (truck drivers, migrant workers), commercial sex workers, among homosexuality, drug users, and prison inmates. Systematic planning is required not to move from a perceived problem to intervention. There is a need to reduce consumptions of substances including alcohol among youths in the study area through different interventions such as introduction of zero blood alcohol tolerance among adolescents in schools and young mobile workers especially drivers, this will also reduce road accidents. It is also necessary for a media campaign about health warnings associated with substance abuse through fear messages; this may reduce the consumption and risk of contracting HIV/AIDS.

There are major limitations in this study. Firstly, the study used cross-sectional data which makes it impossible to demonstrate whether substance use has a direct, causal effect on risky sexual behaviour: Secondly, this study assesses only general substance use (Drinking Alcohol every day and smoking) and not the frequency of substance use with sex.

Intense patterns of substance use were some of the most powerful correlates of youth’s engagement in frequent sexual activities. The study has reaffirmed the established relationship between substance abuse, sexual frequency, and sexually transmitted infections in the study area. The intricate relationship between substance use and sexual frequency requires further investigation in some culture-specific communities of Nigeria to determine the cultural elements that account for variation in the rate of STIs. Since it has been established that HIV/AIDS is being majorly transmitted through sexual intercourse especially among high-risk groups. Further research should examine other health challenges associated with young people’s sexual frequency outside STIs.