Decline In Sperm Counts Research Articles

Shedding Light on the Controversy Surrounding the Temporal Decline in Human Sperm Counts: A Systematic Review

We systematically examined the evidence of declining sperm counts and the hypothesis that an increased exposure to environmental pollutants is responsible for such decline. Search engines, including PUBMED, MEDLINE, EMBASE, BIOSIS, and Cochrane library, were used to identify epidemiologic studies published from 1985 to 2013. We concluded that there is no enough evidence to confirm a worldwide decline in sperm counts. Also, there seems to be no scientific truth of a causative role for endocrine disruptors in the temporal decline of sperm production. Such assumptions are based on few meta-analyses and retrospective studies, while other well-conducted researches could not confirm these findings. We acknowledge that difficult-to-control confounding factors in the highly variable nature of semen, selection criteria, and comparability of populations from different time periods in secular-trend studies, the quality of laboratory methods for counting sperm, and apparently geographic variations in semen quality are the main issues that complicate the interpretation of the available evidence. Owing to the importance of this subject and the uncertainties still prevailing, there is a need not only for continuing monitoring of semen quality, reproductive hormones, and xenobiotics, but also for a better definition of fecundity.

Disturbances of sperm maturation and minipuberty: is there a connection?

Male reproductive function in the general population raises an increased attention due to reports indicating declining sperm counts, increased occurrence of testicular cancer, cryptorchidism, and hypospadias. It is also hypothesized that prolonged exposure of the developing male, during both fetal and postnatal life, to exogenous estrogens could reduce Sertoli cell number and thus reduce sperm output (and sperm counts) in adult life. Fact is that infertility, which is defined as the inability to conceive after 1 year of unprotected intercourse, has a global prevalence of 9%. A male contributory factor is involved in approximately half of these cases, but most of the causes of reduced semen quality and other disturbances of male reproductive function are unknown. In the most affected men (azoospermic men) 15–20% had a prior history of cryptorchidism. The association between the cryptorchidism and infertility is one of the most studied potential causes of infertility. There are numerous studies that accentuate the importance of minipuberty for future fertility. Is it possible that a normal minipuberty ensures normal fertility despite malpositioned testes? And to move away from cryptorchidism, could impaired minipuberty be responsible for fertility problems in men who were born with both testes in their scrotal sacs?

The effect of unilateral vasectomy on testosterone and testicular parameters in the adult male African giant rat (Cricetomys gambianus)

The effects of vasectomy on spermatogenesis and reproductive parameters are recognized to be specie-dependent with marked differences in levels of perturbations observed. To assess the impact of unilateral vasectomy on testosterone level and other testicular parameters in the male African giant rat (AGR) (Cricetomys gambianus). Sixteen adult male AGRs weighing 500-1300 g were recruited for the experiment. Animals were randomly divided into three experimental groups (1-3) and one control (sham operated) group with four rats per group. Experimental vasectomy was done by carefully ligating the vas deferens of the right testis of all the experimental groups (1, 2, and 3) and animals were allowed either 8, 6 and 2 weeks respectively before sacrifice. Sham-operated animals served as the control. Blood samples were collected and assayed for testosterone while testicular tissue was further processed for seminal fluid and histo-pathological analyses. Spermatogenic parameters indicate a pattern of decline in sperm count and motility between the experimental groups and the control and azoospermia in the eight-week group. Histological alterations were marked by atrophy of seminiferous tubules which was proportional to the duration of vasectomy. Serum testosterone levels were significantly reduced at eight weeks. There was no statistically significant difference between sperm counts of right and left testes except for group 3. Results suggest that unilateral vasectomy of the AGR may have negative impact on the contralateral testis in the male African giant rat. These preliminary results reveal that unilateral vasectomy in the AGR may result in perturbations of the histo-architecture of the testes with possible decline in function.

Evidence of a recent decline in sperm count in a united states population from 2002-2010

Evidence of a recent decline in sperm count in a united states population from 2002-2010

Dairy food intake in relation to semen quality and reproductive hormone levels among physically active young men

Is increased consumption of dairy foods associated with lower semen quality? We found that intake of full-fat dairy was inversely related to sperm motility and morphology. These associations were driven primarily by intake of cheese and were independent of overall dietary patterns. It has been suggested that environmental estrogens could be responsible for the putative secular decline in sperm counts. Dairy foods contain large amounts of estrogens. While some studies have suggested dairy as a possible contributing factor for decreased semen quality, this finding has not been consistent across studies. The Rochester Young Men's Study (n = 189) was a cross-sectional study conducted between 2009 and 2010 at the University of Rochester. Men aged 18-22 years were included in this analysis. Diet was assessed via food frequency questionnaire. Linear regression was used to analyze the relation between dairy intake and conventional semen quality parameters (total sperm count, sperm concentration, progressive motility, morphology and ejaculate volume) adjusting for age, abstinence time, race, smoking status, body mass index, recruitment period, moderate-to-intense exercise, TV watching and total calorie intake. Total dairy food intake was inversely related to sperm morphology (P-trend = 0.004). This association was mostly driven by intake of full-fat dairy foods. The adjusted difference (95% confidence interval) in normal sperm morphology percent was -3.2% (-4.5 to -1.8) between men in the upper half and those in the lower half of full-fat dairy intake (P < 0.0001), while the equivalent contrast for low-fat dairy intake was less pronounced [-1.3% (-2.7 to -0.07; P= 0.06)]. Full-fat dairy intake was also associated with significantly lower percent progressively motile sperm (P= 0.05). As it was a cross-sectional study, causal inference is limited. Further research is needed to prove a causal link between a high consumption of full-fat dairy foods and detrimental effects on semen quality. If verified our findings would mean that intake of full-fat dairy foods should be considered in attempts to explain secular trends in semen quality and that men trying to have children should restrict their intake. European Union Seventh Framework Program (Environment), 'Developmental Effects of Environment on Reproductive Health' (DEER) grant 212844. Grant P30 DK046200 and Ruth L. Kirschstein National Research Service Award T32 DK007703-16 from the National Institutes of Health. None of the authors has any conflicts of interest to declare.

Falling sperm counts twenty years on: where are we now?

Poor semen quality is an attribute of the human condition that we share with our closest primate ancestors and may be part of our evolutionary inheritance. This characteristic may also reflect the lack of selection pressure on male fertility in advanced societies that have gone through the demographic transition. In the future, such trends may be further exacerbated by the widespread use of ART, which will impair the elimination of low fecundity genotypes from the human gene pool. Environmental pollutants may also be influencing male fertility, however, neither the chemical identity of these factors nor their mechanism-of-action are fully understood. Over 20 years ago, Carlsen et al.1 published a highly cited paper in the British Medical Journal which purported to detect a significant decline in sperm counts over a period of 60 years (1934–1996). This was followed shortly afterwards by the Skakkebaek and Sharpe hypothesis,2 published in Lancet, which argued that the increasing incidence of reproductive abnormalities in the human male may be related to increased oestrogen exposure in utero, citing maternal exposure to diethylstilbestrol (DES) during pregnancy as evidence for such a link. These classic papers have now become inextricably linked in the global consciousness and have led to a public misconception that male fertility is declining as a consequence of fetal exposure to environmental estrogens.3 In the 20 years that have elapsed since these landmark papers were published, a great deal of data has appeared that seem to support and refute their validity in equal measure, resulting in a state of confusion. The European Science Foundation4 has recently published a review of the current status of male reproductive health. Using this summary as a guide we are now in an excellent position to dissect some of the key arguments and formulate questions for future consideration.

Counting your sperm before they fertilize: are sperm counts really declining?

A purported global decline in sperm counts has been a source of controversy since the early 1990s. Numerous studies performed since then, as well as re-analysis of the original data, show either no changes, or even increases, in sperm concentrations over time. In this review, we discuss the 1992 meta-analysis that initiated the continuing debate on whether sperm concentrations are declining, and the community discussion surrounding it over the past two decades. We also highlight studies evaluating sperm concentrations performed since the initial study that produced different results, and conclude that no definitive cause for a decrease in sperm counts has been established, and the effects of geography and environment on sperm counts are unclear. Approximately 15% of couples are considered infertile, with a male factor implicated in up to 50% of cases, underscoring the essential contribution of the male in conception.1 However, only over the past two decades have we begun to understand the degree to which men contribute to a couple's infertility, which historically was attributed to the female partner. One quarter or more of infertile men have an unknown cause for their infertility, and while recent work suggests that many of these etiologies are genetic, we cannot exclude the impact of environmental factors on the male reproductive system, which have been incompletely defined. Work over recent decades has identified a potential decline in sperm concentrations, with at least one explanation being an increase or change in environmental pollutant levels. In 1992, a meta-analysis of sperm concentrations derived from 61 papers dating between 1938 and 1990 involving semen quality from 14 476 men found that both sperm concentrations and seminal volumes had dropped significantly during that period.2 This was followed in 1993 by a manuscript suggesting that this decrease in sperm concentrations was partly due to environmental contamination with estrogenic compounds. However, there was little evidence identifying estrogens in the geographical areas where sperm concentrations appeared to be declining, or other evidence directly linking estrogenic pollution with declines in male fertility.3 These works triggered a continuing discourse and numerous investigations to evaluate the verity of these claims. However, current data have failed to demonstrate a decrease in either sperm concentrations or male fertility. Owing to the large amount of unclear and confounding data, it is difficult to determine whether male fertility rates are truly declining. Fertility assessment in both men and women is made more difficult by the wide range of sperm concentrations that can result in pregnancy. Indeed, sperm count alone cannot define the fertility potential of a couple. Nevertheless, from the authors' viewpoint, the available data do not support a global decline in sperm concentrations or male fertility. We highlight the limitations of the original work claiming this decline, and show that current data, including data by the authors of the original work, support the argument that sperm concentrations have overall remained stable or even increased. Furthermore, we find that there are few rigorously performed studies evaluating sperm concentrations, highlighting a need for such studies in determining the status of male reproductive function and the environmental factors that may affect it. Finally, we provide our views on the importance of peer review and the role of scientists as intermediaries with the press, and thereby the lay population, and how to maintain this relationship while providing accurate data without unnecessary sensationalism.

Ignorance but not bliss: too little is known about the determinants of semen quality.

Criticisms of the data that have been presented to demonstrate a decline in sperm counts over time reveal problems with semen analysis methods and a lack of understanding of the genetic and environmental factors that determine a man's sperm count. Potential sources of error in the WHO semen analysis protocol and some areas of ignorance about the biological and environmental factors which can influence sperm counts are briefly discussed. I conclude that there is a need to include semen analyses in a large cohort study to fill the gaps in our knowledge. The paper by Carlsen et al.1 that is being marked in this issue of Asian Journal of Andrology stimulated widespread concern and considerable research effort. Together with other supportive studies, e.g. Auger et al.,2 strong evidence that testicular cancer was not only becoming more prevalent but was developing at lower ages3,4 and observations that other disorders of male development, e.g. cryptorchidism and hypospadias, were being more frequently reported, although this might be due to changes in clinical practice (see Thonneau et al.5), have raised serious concerns that something was going amiss with the human male. The proposition that oestrogen exposure in utero might be responsible by an effect on Sertoli cell development gave rise to the ‘testicular dysgenesis' hypothesis to explain these effects,6 although the role of oestrogen has been questioned recently. As most andrologists, I have followed developments in this area with keen interest but other contributors to this issue are far more knowledgeable than me, so I intend to say nothing about the testicular dysgenesis hypothesis or the latest consensus on whether sperm counts have indeed declined. Instead I will review some of the reasons why assessing trends in semen quality over time is difficult, and how these problems reveal gaps, or perhaps chasms, in our knowledge about the biology of human semen. First, although there is no better alternative, the standard semen analysis is inherently imprecise and is prone to many errors. The equipment used has changed over time and with it the nature of the error, making historical comparisons difficult. The errors introduced could be random, leading to imprecision and greater difficulty in demonstrating statistical significance but without effect on the nature of the trend, or systematic, leading to bias in the results. In theory systematic error could be corrected by direct comparison of former and current techniques. However, as discussed below results can potentially be affected by technical errors whose effects are difficult to predict. These can only be detected and eliminated by good quality control systems that have only been in place for at most two decades. Therefore doubt about older data will always remain. Secondly, the environmental factors that might influence a man's sperm count have changed over time and movements of populations have changed the genetic mix in many places. Moreover, social changes might affect the characteristics of the men recruited into semen studies. How these factors affect sperm count is very poorly understood. There are many excellent descriptions of how to do a semen analysis (e.g. Bjorndahl et al.7 and WHO Manual8), and I will not attempt to repeat these but will focus on what can so easily be done wrong in the laboratory. I will then discuss biological variation in semen quality in an attempt to highlight areas of ignorance.

Electromagnetic pollution: another risk factor for infertility, or a red herring?

Humans are exposed to radiofrequency electromagnetic fields (RF-EMF) from various sources (e.g., mobile and cordless phones, base stations, TV and radio transmitters, wifi adapters). So far, there is no evidence that would indicate that RF-EMF exposure is causing adverse health effects with respect to cancer, sleep disorder, headache, etc. Some results of in vitro and in vivo experiments revealed negative effects on male fertility. When looking at those studies in detail, many problems are identified with respect to correct dosimetry and proper experimental design. This field of research is notoriously difficult for various reasons, and experiments should be planned and performed with experts from the respective areas. The increasing use of devices for wireless communication has given rise to fears that the radiofrequency electromagnetic fields (RF-EMFs) emitted by such devices (e.g., mobile and wireless phones, wifi adapters) and by their respective base stations cause various adverse health effects.1,2 The list of such alleged effects is virtually endless, including sleep disturbances, headaches, tinnitus, high blood pressure, endocrine disorders, DNA damage, Alzheimer's disease and cancer. The vast majority of the many studies in cells, animals and humans, however, have provided no evidence whatsoever for such connections, even when the maximum allowed exposure levels were exceeded considerably. The discussion about possible health effects by exposure to RF-EMF recently has shifted towards infertility, mainly focusing on males.3 The alleged decline in sperm counts—which is addressed in other contributions in this issue—is believed by some to be caused by RF-EMF emitting devices. Research in this area of research is notoriously difficult and prone to errors. In this paper, some common misunderstandings are addressed; limitations and technical problems are described as well.

Sperm counts and fertility in men: a rocky road ahead

Declining sperm counts and the increasing average age of first‐time parents spell trouble for human fertility, especially when set against the backdrop of ageing populations.

Protective effect of vitamin C against carbofuran‐induce testicular

The effect of the carbamate insecticide “carbofuran” on testes of male albino mice and the possible protective role of vitamin C against the insecticide toxicity was assessed. Treating mice with carbofuran for 8 weeks induced a significant decrease in the diameters and germinal epithelial heights of the seminiferous tubules. The histological evidence showed inhibition of spermatogenesis. There was also a decline in sperm count. Histochemical results revealed that animals given carofuran had decreased contents of carbohydrates and total proteins in the testicular tissue. Treating mice with carbofuran and vitamin C showed an improvement in the testicular damage. The seminiferous tubules appeared normal and the different stages of spermatogenic cells showed an advanced degree of activation. The present work is supported by Umm Al‐Qura University

Estrogens and phytoestrogens in male infertility

A time-related negative trend in male reproductive function has been suggested. It has been hypothesized that this is due to exposure to chemicals interfering with the action of sex hormones. Also a negative effect of phytoestrogens on male fertility has been postulated. This review aimed to review the epidemiological evidence of deteriorating male reproductive function and summarize the most recent literature on exposure to endocrine disrupters and phytoestrogens in relation to male fertility and/or semen quality. There is no doubt that the incidence of testicular cancer has increased through the past 50 years, a decline in sperm counts, if any, may have leveled off during the past decade. There are some reports indicating negative association between exposure to certain chemicals and sperm parameters such evidence has not been found for phytoestrogens. The majority of these studies have been limited to assessing postnatal exposure. Although possible negative impact of industrial chemicals and male fertility is an important issue on the research agenda, so far, it has no clinical implications. The future research should focus on looking at the impact of low dose exposure to a mixture of chemicals, two generation studies and gene-environment interaction.

Testicular connexin 43, a precocious molecular target for the effect of environmental toxicants on male fertility

Many recent epidemiological, clinical and experimental findings support the hypothesis that environmental toxicants are responsible for the increasing male reproductive disorders (congenital malformations, declining sperm counts and testicular cancer) over the past 20 years. It has also been reported that exposure to these toxicants, during critical periods of development (fetal and neonatal), represents a more considerable risk for animals and humans than exposure during adulthood. However, the molecular targets for these chemicals have not been clearly identified. Recent studies showed that a family of transmembranous proteins, named connexins, regulates numerous physiological processes involved in testicular development and function, such as Sertoli and germ cell proliferation, differentiation, germ cell migration and apoptosis. In the testis, knockout strategy revealed that connexin 43, the predominant connexin in this organ, is essential for spermatogenesis. In addition, there is evidence that many environmental toxicants could alter testicular connexin 43 by dysregulation of numerous mechanisms controlling its function. In the present work, we propose first to give an overview of connexin expression and intercellular gap junction coupling in the developing fetal and neonatal testes. Second, we underline the impact of maternally chemical exposure on connexin 43 expression in the perinatal developing testis. Lastly, we attempt to link this precocious effect to male offspring fertility.

51 Exposure to pesticide residues and semen quality: A cross-sectional study

Free Paper IV – Alternative Medicine, Nutrition & Toxicology 50 N-Hanz enhances male potency for treatment of erectile dysfunction K.K. Hwi1, C.S. Hung1, C.K. Chuan2. 1 Department of Physiology, Faculty of Medicine, Universiti Malaya, Malaysia; 2Gleneagles Hospital, Brunei The earliest report discussing impotence dates back 3,000 to 4,000 years. These poems of the “science of life” (Samhita of Sushruta) contain descriptions of “natural” remedies used by humans known as aphrodisiacs to enhance sexual experience. We partially purify compounds from walnut kernel (Juglandis Regia) known as N-Hanz. The N-Hanz exhibited a high antioxidant activity: 1mg showed the equivalent of 0.195mg of vitamin C. This indicates that N-Hanz possesses almost 20% of the anti-oxidant potency Vitamin C. On sexual activity on rat, oral administration of 50mg/kg of N-Hanz exhibited a 10 folds increased in mounting frequency compared to before treatment and rats also displayed more frequent and vigorous licking and anogenital sniffing towards the receptive females. Furthermore, the rats spentmore time grooming their genitals compared to before treatment. Genital grooming may be interpreted as self-pleasuring since the rats were most likely enjoying the sensation of touching themselves.Wenoticed another interesting finding is after N-Hanz treatment the rats began to hang around the females instead of exploring the cage. In terms of the human species, this may be interpreted as a man having more interest in the females (increased libido). In conclusions we believe the antioxidant property of N-hanz will induced the vasodilatation effect, caused the increases blood flow into cavernosal spaces that leads to increased intracavernosal pressure produce penile erection. Thus, we believe N-Hanz will be a breakthrough not only for treatment of ED but will be able to enhance male potency. 51 Exposure to pesticide residues and semen quality: A cross-sectional study F. Hossain, O. Ali, U.J.A.D. D’Souza, D.K.S. Naing. University Malaysia Sabah, Malaysia Background: Epidemiologic studies have indicated a decline in sperm count and semen quality to almost a half over the last five decades among healthy men all over the world. Pesticides have been proposed as one of the major causes for such a decline. Objectives: The aim of the present study was to assess the effects of pesticides use on semen quality among farmers in Telupid, Kundasang and Papar district of Sabah, Malaysia. Methods: A cross – sectional study was conducted. 152 farmers participated of which 62 farmers were exposed to either paraquat or malathion or both. A questionnaire was designed to record a history of pesticides exposure, population profile and other risk behaviors. Semen samples were examined and analyzed based on WHO (1992) guidelines after collection by masturbationwith sexual abstinence of 2–3 days. Volume, pH, sperm concentration, motility, morphology, WBC count were examined and recorded. Results: The mean values semen parameters were significantly less in the exposed group than non-exposed (p< 0.05). Those who were exposed to pesticides had 3–9 times greater risk of having abnormal semen parameters in compare with the non-exposed group (p< 0.05). There was no significant difference observed between semen qualities of exposure to different types of pesticides & in relation to potential risk factors. Conclusions: The result showed the pesticide exposure was significantly associated with abnormal semen characteristics and there was increase in the risk of impairs semen quality among people who had exposed to pesticides.

50 N-Hanz enhances male potency for treatment of erectile dysfunction

Free Paper IV – Alternative Medicine, Nutrition & Toxicology 50 N-Hanz enhances male potency for treatment of erectile dysfunction K.K. Hwi1, C.S. Hung1, C.K. Chuan2. 1 Department of Physiology, Faculty of Medicine, Universiti Malaya, Malaysia; 2Gleneagles Hospital, Brunei The earliest report discussing impotence dates back 3,000 to 4,000 years. These poems of the “science of life” (Samhita of Sushruta) contain descriptions of “natural” remedies used by humans known as aphrodisiacs to enhance sexual experience. We partially purify compounds from walnut kernel (Juglandis Regia) known as N-Hanz. The N-Hanz exhibited a high antioxidant activity: 1mg showed the equivalent of 0.195mg of vitamin C. This indicates that N-Hanz possesses almost 20% of the anti-oxidant potency Vitamin C. On sexual activity on rat, oral administration of 50mg/kg of N-Hanz exhibited a 10 folds increased in mounting frequency compared to before treatment and rats also displayed more frequent and vigorous licking and anogenital sniffing towards the receptive females. Furthermore, the rats spentmore time grooming their genitals compared to before treatment. Genital grooming may be interpreted as self-pleasuring since the rats were most likely enjoying the sensation of touching themselves.Wenoticed another interesting finding is after N-Hanz treatment the rats began to hang around the females instead of exploring the cage. In terms of the human species, this may be interpreted as a man having more interest in the females (increased libido). In conclusions we believe the antioxidant property of N-hanz will induced the vasodilatation effect, caused the increases blood flow into cavernosal spaces that leads to increased intracavernosal pressure produce penile erection. Thus, we believe N-Hanz will be a breakthrough not only for treatment of ED but will be able to enhance male potency. 51 Exposure to pesticide residues and semen quality: A cross-sectional study F. Hossain, O. Ali, U.J.A.D. D’Souza, D.K.S. Naing. University Malaysia Sabah, Malaysia Background: Epidemiologic studies have indicated a decline in sperm count and semen quality to almost a half over the last five decades among healthy men all over the world. Pesticides have been proposed as one of the major causes for such a decline. Objectives: The aim of the present study was to assess the effects of pesticides use on semen quality among farmers in Telupid, Kundasang and Papar district of Sabah, Malaysia. Methods: A cross – sectional study was conducted. 152 farmers participated of which 62 farmers were exposed to either paraquat or malathion or both. A questionnaire was designed to record a history of pesticides exposure, population profile and other risk behaviors. Semen samples were examined and analyzed based on WHO (1992) guidelines after collection by masturbationwith sexual abstinence of 2–3 days. Volume, pH, sperm concentration, motility, morphology, WBC count were examined and recorded. Results: The mean values semen parameters were significantly less in the exposed group than non-exposed (p< 0.05). Those who were exposed to pesticides had 3–9 times greater risk of having abnormal semen parameters in compare with the non-exposed group (p< 0.05). There was no significant difference observed between semen qualities of exposure to different types of pesticides & in relation to potential risk factors. Conclusions: The result showed the pesticide exposure was significantly associated with abnormal semen characteristics and there was increase in the risk of impairs semen quality among people who had exposed to pesticides.

No secular trend over the last decade in sperm counts among Swedish men from the general population

Based on historical data, a decline in sperm counts during the years 1940-1990 has been suggested and aetiologically linked to a concomitant increase in the incidence of testicular cancer. This study, focusing on possible changes in sperm parameters among young Swedish men, during the past 10 years, was specifically designed in order to answer the question of whether there is a continuing decline in sperm counts. During the period 2008-2010, 295 young (17-20 years; median 18) men born and raised in Sweden were recruited at the age they were supposed to undergo medical examination prior to military service. The participants filled in questionnaires, underwent andrological examination and delivered an ejaculate. Their semen parameters were compared with those of a similar cohort of men (n = 216) recruited in the year 2000-2001. No significant changes (means; 2000-2001 versus 2008-2010) in sperm concentration (78 × 10⁶/ml versus 82 × 10⁶/ml; P = 0.54), semen volume (3.1 ml versus 3.0 ml; P = 0.26) or total sperm counts (220 × 10⁶ versus 250 × 10⁶; P = 0.18) were found. The proportion of progressively motile spermatozoa also remained unchanged. Between the years 2000 and 2010 we found no evidence of time-related deterioration of semen parameters among young Swedish men from the general population. This finding does not exclude that such a decrease may have taken place before year 2000. If the risk of testicular cancer is linked to the sperm counts, the increase in incidence of this malignancy should be levelling off in southern Sweden in the next 10-15 years.

Effects of Pesticide Use on Semen Quality among Farmers in Rural Areas of Sabah, Malaysia

To determine the relationship between semen quality and exposure to pesticide residues. A cross-sectional study was conducted among male farmers from 3 different communities in Sabah, Malaysia. A total of 152 farmers participated in this study of whom 62 farmers had been exposed to either paraquat or malathion or both to varying extents. Questionnaires were designed to record a history of pesticides exposure and other potential risk factors among farmers. All semen samples were collected, processed and analyzed by qualified personnel based on WHO guidelines. Volume, pH, sperm concentration, motility, morphology and WBC count were examined and recorded. The association between pesticide exposure and semen parameters was highly significant. The mean values of volume, pH, sperm concentration, motility, and WBC count were significantly less in the exposed group than in compared with the non-exposed group, with p<0.005. Those who were exposed to pesticides had greater risk of having abnormal semen parameters than those in with the non exposed group, with p values of less than 0.05. The comparison between semen qualities such as lower sperm count, motility and higher percentage of sperm abnormality of those exposed to different types of pesticides (paraquat and malathion) showed no significant differences. The results showed a significant decline in semen quality with a decline in sperm count, motility and higher percent of teratospermia among subjects with pesticide exposure, and those who were exposed to pesticides had significantly 3 to 9 times greater risk of having abnormal semen parameters.

Obesity and age affect male fertility potential

A case-cohort study of 2,157 patients, aged 17-67 years was performed to assess the impact of body mass index and age on male fertility. Using a multiple regression analysis across the total cohort, only age correlated significantly with all spermiogram parameters and serum hormones, but in patients aged 20-30 years (n = 617) the total sperm count was significantly negatively correlated with body mass index.

Environmental/lifestyle effects on spermatogenesis

The high incidence of low sperm counts in young (European) men and evidence for declining sperm counts in recent decades mean that the environmental/lifestyle impact on spermatogenesis is an important health issue. This review assesses potential causes involving adverse effects on testis development in perinatal life (primarily effects on Sertoli cell number), which are probably irreversible, or effects on the process of spermatogenesis in adulthood, which are probably mainly reversible. Several lifestyle-related (obesity, smoking) and environmental (exposure to traffic exhaust fumes, dioxins, combustion products) factors appear to negatively affect both the perinatal and adult testes, emphasizing the importance of environmental/lifestyle impacts throughout the life course. Apart from this, public concern about adverse effects of environmental chemicals (ECs) (pesticides, food additives, persistent pollutants such as DDT, polychlorinated biphenyls) on spermatogenesis in adult men are, in general, not supported by the available data for humans. Where adverse effects of ECs have been shown, they are usually in an occupational setting rather than applying to the general population. In contrast, a modern Western lifestyle (sedentary work/lifestyle, obesity) is potentially damaging to sperm production. Spermatogenesis in normal men is poorly organized and inefficient so that men are poorly placed to cope with environmental/lifestyle insults.

040. ARE ENVIRONMENTAL EXPOSURES AFFECTING HUMAN REPRODUCTIVE HEALTH?

The concern that human reproductive health may be affected by chemicals in our daily environment has grown in recent years with the recognition that: (1) some countries have seen a recognizable decline in sperm counts and an increase in urogenital tract abnormalities among newborn males, (2) the incidence of some cancers has increased precipitously, and (3) the number of infertile couples has increased markedly in many countries. Our laboratory focuses on the oocyte and the factors that cause the production of chromosomally abnormal eggs. We know that the risk of a chromosomally abnormal pregnancy is strongly influenced by maternal age, but there is growing concern that environmental exposures may influence the ability of both the male and female to produce normal gametes. Our laboratory has focused on the effect of exposures to a ubiquitous chemical to which humans are exposed daily, bisphenol A (BPA). BPA is used in a wide variety of consumer products from plastics and resin coatings to eyeglasses and pressure printed receipts. Our studies in mice demonstrate that BPA exposure during fetal development adversely affects female fertility because BPA influences several significant stages of egg development. In the male mouse, we and others have found that prenatal, perinatal, and adult exposures can affect the function of the testis. In current studies we are attempting to determine if effects seen in the mouse are also a feature of BPA exposed primates. We are using a rhesus monkey model to determine how BPA is metabolized in the pregnant and nonpregnant female and how BPA exposure influences the developing fetus. Lastly, in human studies we are evaluating BPA levels in the developing fetus and assessing their effect on the developing fetal ovary.