Frequency of Monthly Ejaculation at Sexual Intercourse, DNA Fragmentation Index and Fertilization Rate among Sperm Donors and Fertility-Challenged Men in Sub-Saharan Africa: Paper 2

Introduction: Heterogenous sexual intercourse often produces a powerful orgasm that stimulates the pituitary function. Studies have suggested ejaculation frequency based on age. Materials and Methods: Semi-structured ques-tionnaires were used to collect information from subjects. Semen samples were collected from sperm donors and sub-fertile men who presented for infertility challenges. Processing and analysis of semen samples were done according to World Health Organization (WHO) guidelines. Sperm deoxyribonucleic acid (DNA) fragmentation was evaluated using the Halosperm kit. Results: Among sperm donors, those aged <40 years were twice as likely to have very low (1 - 5) frequency of monthly ejaculations at sexual intercourse (MESI) compared to those aged ≥40 years (χ 2 = 0.09, P-value = 0.81, OR = 3.2, 95% CI: 0.23, 45.19) while among sub-fertile men those aged ≥40 years were approximately 2.3 times more likely to have very low frequency of MESI compared to aged <40 years (χ 2 = 2.11, P-value = 0.51, OR = 2.27, 95% CI: 0.74, 9.92). were approximately 2 1/2 times more likely to have a low (6 - 10) frequency of MESI compared to those aged <40 years (χ 2 = 0.03, P-value = 0.57, OR = 2.42, 95% CI: 0.41, 14.46). Sub-fertile men aged ≥40 with diastolic hypertension (≥90 mmHg) were approximately 6 times more likely to have a low (6 10) frequency of MESI compared to those aged <40 years (χ 2 = 1.97, P-value = 0.16, OR = 6.22, 95% CI: 0.69, 55.77). Overall mean fertilization rate was significantly higher (t-test = 2.44, P-value = 0.01) among sub-fertile men aged <40 years (85.3 ± 13.2) than among those aged ≥40 years (9.3 ± 24.8). Mean fertilization rate among those with DNA fragmentation index <25% was significantly higher (t-test = 2.14, P-value = 0.03) among those aged <40 years (88.6 ± 12.3) than among those aged ≥40 years (67.1 ± 24.0). Conclusion: Cigarette smoking, more than alcohol consumption, appears to be a major factor that significantly affects the frequency of MESI among sub-fertile men in all age groups. Frequency of MESI negatively but insignificantly correlated with systolic blood pressure.


Introduction
Human spermatozoa are produced in the seminiferous tubules and are stored in the epididymis where they undergo a series of physiological and biochemical changes, allowing them to mature and acquire fertilizing potential before release [1]. Globally, frequency of male ejaculation at sexual intercourse, has been associated with risk of prostate cancer, though a recent Harvard Ejaculation Study (HES) found no evidence that frequent ejaculations markedly increased risk of prostate cancer [2]. From another perspective, Courtois et al. reported systematic variations in blood pressure at drug-induced ejaculation among men with spinal cord injury, indicating a possible relationship between ejaculation and blood pressure with or without medication [3]. An anecdotal report by European researchers indicates that as frequency of sexual intercourse, thus ejaculation, increases, blood pressure decreases [4]. It has also been suggested that frequent sex is good for the health of men [5] [6] but there is not enough data to prove this point. It's not certain if good health makes one more willing to have sexual intercourse or if sexual intercourse has a positive impact on health. It is assumed that health benefits of sexual intercourse are generally thought to accrue to people in loving, monogamous relationships. Risky sexual intercourse with lots of partners may do more harm than good [7]. Release of sperm cells at ejaculation often leads to pregnancy in the female, though frequency of ejaculation may not necessarily be related to chances of becoming pregnant. Most data on ejacu-

Materials and Methods
The second part of this paper involves 1) factors that affect the frequency of MESI significantly, 2) the effect of high, medium or low frequency of monthly ejaculation at sexual intercourse on health of subjects of study, and 3) fertilization rate among sperm donors and also among sub-fertile men who had in-vitro-fertilization (IVF) relative to DNA fragmentation and MESI.
Just as in the first part, this second part of the study utilized the same semi-structured questionnaire designed to collect socio-demographic data; history, type and duration of infertility, miscarriage in partners and if subject had ever fathered a child or not. All the subjects who came for sperm donation, who consulted for male infertility within the study period and who gave informed consent were included in the study except those who could not produce semen, those who declined consent and those whose information was inaccurate. The investigations here revolved around frequency of monthly ejaculation at sexual intercourse (MESI), systolic and diastolic blood pressures, history of hypertension and of diabetes, social habits such as cigarette smoking and alcohol consumption as well as use of medicinal herbs (agbo). Materials and methods for the second part of the study was essentially the same as in the first part of the study.
Briefly, each patient, whether a sperm donor or a patient consulting for male factor infertility submitted semen samples-collected by masturbation-which were processed strictly in accordance with WHO specification as described in our earlier paper [8]. Semen samples were collected after a duration of 2 -7 days abstinence of sexual intercourse and transported almost immediately to the laboratory for analysis. Each patient was counselled on: 1) the need for accuracy in the collection of semen; 2) the kits (wide-mouth measuring cylinder) to be used for the collection; and 3) the need to report any loss of semen during collection.
Conventional seminal fluid analysis (SFA) was performed according to WHO guidelines [9] for semen volume, total sperm count, motility, and morphology.
The determination of human sperm DNA fragmentation index (DFI %) has been rendered in our earlier paper [10]. Included in this study were all patients who presented for sperm donation, who consulted for male infertility management within the study period and those who gave informed consent. All consenting men who presented for fertility assessment; those who were currently or within two weeks prior to analysis, not on any medication, particularly

Statistical Analysis
The statistical analysis used in part 1 one of this paper was also applicable to part

Results
Factors that significantly affect frequency of ejaculation at sexual intercourse (MESI) among sperm donors (Table 1, Figure 1).    Factors that significantly affect frequency of ejaculation at sexual intercourse (MESI) among sub-fertile men (Table 2, Figure 2).
Our results suggested that, overall, age was one of the factors that significantly affected the frequency of MESI among the sub-fertile subjects of this study.
On the contrary, a significant proportion (χ 2 = 4.76, P-value = 0.03) of those aged <40 years (19/34, 55.9%) had high frequency of ejaculation at sexual intercourse than those aged ≥40 years. In the final analysis, mean overall frequency of MESI among those aged <40 years (10.8 ± 3.8) was significantly higher (t-test = 2.20, P-value = 0.02) than that among older men aged ≥40 years. Though influenced by age, another factor that appeared to significantly affect the frequency of MESI was DNA fragmentation index, as a higher proportion of those <40 years with DFI < 25% reported very high frequency (16 -20) of MESI while a marginally significant proportion of older men (χ 2 = 3.67, P-value = 0.05) recorded low frequency (6 -10) of MESI.
Surprisingly, among those who reported a low (6 -10) frequency of MESI the overall proportion of those who had ever fathered a child (53.6%) was significantly higher (χ 2 = 7.68, P-value = 0.006) compared to those who reported other frequencies of MESI indicating that those who had ever fathered a child were more likely to be having lower frequency of MESI than those who had never fathered a child or that those who had never fathered a child would be having a higher frequency of MESI than those who had ever fathered a child. However, although the mean frequency of MESI among those who had never fathered a child (10.1 ± 4.5) was higher than that of those who had ever fathered a child Effect of frequency of monthly ejaculation at sexual intercourse on health of sub-fertile male (Table 3).
Firstly, 31 (32.6%) sub-fertile study subjects had systolic hypertension includ-    of men with systolic hypertension had high frequency of MESI. There was no significant difference in the overall systolic blood pressure (mmHg) of sub-fertile men in any age group relative to frequency of monthly ejaculation at sexual intercourse. It was however observed that, overall, systolic blood pressure (mmHg) seemed to gradually decline from 133.4 through 130.0, 129.7 and finally 128.1 among the subjects reporting very low (1 -5), low (6 -10), high (11 -15) and very high (16 -20) frequency of MESI. Results from this study however observed a significantly higher (t = 4.40, P-value = 0.01) mean diastolic blood pressure (103 mmHg) among hypertensive sub-fertile men ≥40 years who reported high (11 -15) frequency of MESI than other categories of MESI.   Mean frequency of MESI among subjects with and without systolic and diastolic hypertension relative to age, BMI and social habits of sub-fertile subjects (Table 4, Figure 3).  Table 3 prompted a further probe into whether there was a relationship between frequency of MESI and those with or without systolic or diastolic hypertension. The mean frequency of MESI (10.9 ± 3.8) among sub-fertile men aged <40 years with systolic blood pressure < 140 mmHg was significantly higher (t-test = 1.67, P-value = 0.049) than that among men aged ≥40 years (9.1 ± 4.8) while the mean frequency of MESI (11.4    Fertilization rate among sub-fertile men who had IVF relative to DNA fragmentation ( Table 5).
The next analysis was the fertilization rate of men who proceeded to have IVF, considering their DNA fragmentation level. Overall mean fertilization rate was 77.8% with a substantial variation (t-test = 2.44, P-value = 0.01) between the mean fertilization rate of those aged <40 years (85.3 ± 13.2) and those aged ≥40 years (69.3 ± 24.8). This difference appeared to be driven by higher mean fertilization rate among: 1) sub-fertile men aged <40 year with DNA fragmentation index of <25% (88.6 ± 12.3); and that among 2) sub-fertile men aged ≥40 years with DNA fragmentation index on <25% (67.1 ± 24.0). There was a marginally significant mean fertilization rate among those with DNA fragmentation index ≥25% relative to frequency of MESI (F-test = 3.00, P-value = 0.05), though this appeared to be influenced by the lone subject who had IVF in the MESI category of 16 -20. There was a marginally significant variation (t-test = 0.05, P-value = 0.05) in the overall mean fertilization rate among those who never smoked (77.8 ± 21.0) compared to those who ever smoked (77.1 ± 25.2).    Pearson's bivariate correlations showed that, especially among sub-fertile study subjects, there was a significant but negative correlation between age-group and frequency of MESI (R = −0.18, P-value = 0.04) and a marginally significant correlation between ever fathered a child and MESI (R = 0.199, P-value = 0.05) (

Discussion
Though central to human existence, the issue of daily, weekly or monthly male ejaculations at sexual intercourse has not been a focus on any intense debate or discussion in any forum. This is probably because sexual intercourse, one event in which ejaculation takes place, is taken as a sacrosanct subject by many. It is speculated that, in humans, pregnancy may not occur without sperm being introduced into the female vagina, naturally, through assisted reproduction technology (ART) such as in-vitro fertilization (IVF) or otherwise. This paper is the first to elucidate the frequency of monthly ejaculations at sexual intercourse especially among sperm donors and among sub-fertile Black men in sub-Sahara Africa. Our findings have demonstrated the need for better understanding of the phenomenon of ejaculation at sexual intercourse and its relationship with health. Though literature review did not bring up the frequency of ejaculation at sexual intercourse among sperm donors or sub-fertile men, still there are some key findings in this paper that warrant further discussion. First, sperm donors aged <40 years were twice as likely to have very low frequency of monthly ejaculation at sexual intercourse. This might be because sperm donors are young and probably college students who donate sperm for money and once paid there was no need to ejaculate for a while. It might also be that these people are not actually infertile, thus are not looking for a child. As in women, age is also a major factor in male sexuality. Among the sub-fertile men, there was a significant difference in the proportion of men aged <40 years (55.9%) and those aged ≥40 years who had high (11 -15) frequency of monthly ejaculations. Also, the mean monthly ejaculation rate was significantly higher in those <40 years than among those ≥40 years, a finding that corroborates that of Rider et al. that ejaculation frequency declines with age [12]. Another key finding is that those who had ever Open Journal of Urology fathered a child had a lower mean frequency of monthly ejaculation at sexual intercourse compared to those who have never fathered a child. There has been no reported study on the frequency of ejaculation at sexual intercourse among males who had never fathered a child. However, possible reasons for this variation is that those who had never fathered a child might be anxious to get their partner pregnant or, in sub-Saharan setting, might be under pressure to get another wife if the current one does not get pregnant, thus having frequent sexual intercourse. Another reason for this phenomenon is that a vicious cycle is set up as the more frequent the sexual intercourse, the less the semen volume, sperm count and sperm concentration, to an extent [13] [14].
Although the difference was not statistically significant, however, this study reports a gradual decline in systolic blood pressure among men 40 years and older. This is a novel finding in sub-Saharan Africa. Many studies reported the health benefits of moderately high frequency of ejaculation to reduce the risk of prostate cancer but here we report the health benefits in reducing systolic blood pressure. The explanation for the mechanism of this apparent reduction in systolic blood pressure is probably complex, though we suspect it may have to do with the hypothalamus, the vagus nerve, or probably the renin-angiotensin mechanism. More studies are required to illuminate this phenomenon. Since studies on this topic are very rare, internet search article reports surprising health benefits of sex (ejaculation) one of which is lowering blood pressure, although the article quickly says that sex sessions (presumably with ejaculations) cannot replace blood-pressure lowering drugs to control high blood pressure, but may be a useful addition [15].
Our findings also show that the mean frequency of ejaculations at sexual intercourse was significantly higher among men who never smoked cigarette compared to those who had ever, though the difference was not statistically significant. This agrees with the findings of Kovac et al. [16] and Millett [17] that there is a relationship between cigarette smoking and erectile dysfunction (ED) which is dependent upon the parasympathetic nervous system, that induces smooth muscle relaxation allowing arterial blood into the corpus cavernosum via the actions of nitric oxide (NO) [18]. Nitric oxide (NO) is generated by three nitric oxide synthase (NOS) enzyme isoforms: neuronal, endothelial and inducible. The neuronal isoform appears to be the primary mediator of physiologic erection [19].
Neuronal NOS activity by non-adrenergic non-cholinergic neurons is known to be decreased in both in vitro and in vivo models of smoking [20].

Conclusion and Recommendations
To conclude the part 2 of this paper, we studied sperm donors and sub-fertile men presenting at our clinic for infertility problems. In the general population, over 50% of men whose age is >40 will have some varying degree of erectile dysfunction or ED [17]. In this study, sub-fertile men aged ≥40 years were about 2 1/2 times more likely to have very low frequency of MESI when compared with younger sub-fertile men. Overall, systolic blood pressure (mmHg) declined gradually as frequency of MESI increased, though there was no perceptible statistical significance in the observed decline. While sub-fertile men aged ≥40 with systolic hypertension (≥140 mmHg) were about 2 1/2 times more likely to have low frequency of MESI, those with diastolic hypertension (≥90 mmHg) were approximately 6 times more likely to have low frequency of MESI. The overall mean fertilization rate among sub-fertile men aged <40 was significantly higher than that among older sub-fertile men. Cigarette smoking, more than alcohol consumption, appears to be a major factor that significantly affected the frequency of MESI among sub-fertile men in all age groups. Frequency of monthly ejaculations at sexual intercourse negatively but insignificantly correlated with systolic blood pressure. Clinicians, Urologists and Gynecologists should counsel their patients who present for male infertility on not only alcohol consumption and cigarette smoking habits but also on control of blood pressure. They should also educate their patients on factors that could contribute to the fragmentation of their sperm DNA and the effect of this on the possibility of them fathering a child.

Study Limitations
This study has some strengths and weaknesses. Concerning strength of the study, semen collection was very accurate and laboratory analysis of seminal fluid and DNA fragmentation were conducted using modern equipment and according to the latest WHO standard. However, the sample size was small and there could have been a bias in sampling. The study subjects were not representative of the general population thus the data should not be extended to the generality. Further, the study was facility-based and does not reflect the frequency of monthly ejaculations at sexual intercourse of normal heal thy male in the community.
Furthermore, there were no underweight men with BMI < 18.5 kg/m 2 in the study which could have made the data more robust. In addition, this study did not take into consideration men with erectile dysfunction syndrome which may be a factor in low frequency of ejaculation among the sub-fertile men. Finally, we did not study the dose-dependence relationship between cigarette smoking and MESI, alcohol consumption and MESI and combined cigarette smoking plus alcohol consumption and MESI.