What's New: Hot Topics - Male Fertility
Daily ejaculation may help curb DNA-damaged sperm, scientist says.
WebMD (6/30, Hitti) reported, "Men with a history of fertility problems may curb DNA-damaged sperm by ejaculating for seven days in a row," according to a report titled "Keep the River Flowing" written by David Greening, MD, of Sydney IVF in Australia. Dr. Greening developed his theory after studying "118 men with a history of infertility, recurrent miscarriage, or repeated in vitro fertilization failure (IVF) who had DNA damage in more than 15 percent of their sperm from sperm samples." After having the men "ejaculate daily for seven consecutive days," their sperm samples "showed that 81 percent of the men had a reduction in DNA sperm damage." Dr. Greening speculated that such reductions occurred "because the sperm spent less time in the male reproductive system."
BBC News (6/30, Wilkinson) explained that "the warm environment" in the male reproductive system "could also make them more sluggish after a while." In addition, "sperm come under attack by free radicals -- small reactive molecules which can damage DNA and cause cell death -- in the tube that stores and carries sperm away from the testes." Dr. Greening also pointed out that his work may "have implications for couples undergoing IVF, as men are commonly told to abstain from sex for a couple of days to try and boost sperm numbers."
Rigorous training may reduce sperm quality in professional cyclists, research suggests.
BBC News (6/29) reported, "Professional cyclists should consider freezing their sperm before embarking on their careers," because researchers in Spain have discovered that "sperm quality drops dramatically with rigorous training." Specifically, "those who cover more than 186 miles (300km) a week on their bikes have less than four percent normal-looking sperm," a level where men would certainly "have 'significant fertility problems.'" The team at the University of Cordoba Medical School explained that "heat from wearing tight clothing, friction of the testes against the saddle, and stresses on the body from the sheer amounts of energy needed to do such rigorous exercise, could all contribute to poor sperm quality." Notably, "other studies had shown very high levels of exercise affected fertility in both men and women.
"Study indicates infertile men may have increased risk for testicular germ cell cancer.
MedWire (3/2/09, Grasmo) reported that "men who are infertile appear to have an increased risk for developing testicular germ cell cancer," according to a study appearing in the Archives of Internal Medicine. For the study, researches "analyzed data from 22,562 male partners of couples seeking fertility treatment during 1967-1998, and linked them to the California Cancer Registry." They "found that 4,549 of these men had male factor infertility, and a total of 34 postinfertility-diagnosis cases of histologically confirmed testicular cancer were identified." Upon analysis, "men in couples seeking treatment for infertility were 1.3 times more likely to develop testicular cancer compared with the general population." Moreover, "men with male factor infertility had 2.8 times the risk for testicular cancer compared with those without this condition." The researchers concluded that "a plausible explanation is that a common exposure underlies infertility and testicular cancer.
Study suggests anti-androgens in river fish could impact human fertility.
The UK's Telegraph (1/19/09, Gray) reported, "Anti-androgens, that are found in a number of medicines including cancer treatments and pesticides used in agriculture, were found in 30 rivers across England," according to a recent study. Other "studies have already shown that the female sex hormone estrogen is causing the feminization of fish, and in some cases, can lead to male fish changing sex." For this study, British researchers analyzed "more than 1,000 fish in rivers across the UK" over the course of three years. They found that "anti-androgens are also causing male fertility problems in a 'double whammy' for the fish."
The investigators "have yet to find the source of the...anti-androgens, but believe they could come from pesticides, industrial pollution, or pharmaceutical drugs," the UK's Daily Mail (1/19, Derbyshire) added. The authors warned that "anti-androgens can induce a lot of conditions we see in humans, such as low fertility and an increase in genital deformities, very readily.
National Research Council report says cumulative impact of phthalates may need further study.
In the Discover (12/22/08) 80beats blog, Eliza Strickland wrote, "To truly assess the risks posed by a ubiquitous group of chemicals," called phthalates, "found in everything from vinyl shower curtains to bug spray, researchers need to study their cumulative impact on human health," according to a report from the National Research Council. "In rodent studies exposure to phthalates has been shown to interfere with the development of the male reproductive system, causing infertility, reduced sperm production, undescended testes, penile birth defects, and other reproductive-tract malformations," Strickland noted. "Traditionally, health agencies have studied the risk of each chemical individually, but experts say such a process doesn't accurately reflect human exposure." In fact, "studies from the Centers for Disease Control and Prevention and independent scientists have found phthalates in virtually everyone, including pregnant women and babies."
Anti-Depressant-Associated Changes in Semen Parameters
UroToday.com (11/21/08) The authors previously reported an effect of antidepressants on semen parameters. The current study was designed to assess/confirm their prior report of the effects of an SSRI, paroxetine (Paxil), on semen parameters. This was a prospective clinical trial involving 35 healthy male volunteers ages 18-65. SA were obtained prior and 2 weeks and 4 weeks after SSRI initiation. Paroxetine was given for 5weeks: 10mg QD week 1, 20mg QD week 2, 30mg QD weeks 3-4, and 20mg QDweek 5. Standard WHO evaluation of semen parameters were assessed. TUNELassays were performed on baseline and week 4 semen samples to evaluate DNA fragmentation. Semen parameters and TUNEL assays for each individual were compared at each time point. As opposed to prior report, semen parameters (volume, concentration, motility, morphology) were not significantly altered during SSRI treatment. However, mean DNA fragmentation TUNEL score was significantly higher on SSRI (30.3%) versus baseline (13.8%). Multivariate logistic regression, correcting for age and body mass index, confirmed that SSRI treatment was significantly correlated with increased DNA fragmentation Up to 35% of men noted significant changes in erectile function and up to 47% of subjects reported ejaculatory difficulties while on paroxetine. Conclusions: In volunteer male subjects with normal semen parameters, paroxetine induced abnormal sperm DNA fragmentation in a significant proportion of patients. This effect occurred without a measurable effect on semen parameters. The fertility potential of a substantial proportion of men on paroxetine may be adversely affected by these changes in sperm DNA integrity. Editorial Comment (Harris Nagler, MD): This is an interesting study. The data refutes prior report by the same group indicating the effect on gross semen parameters and sperm transport mechanisms. None of these parameters were significantly different from baseline. However, this study noted an interesting and potentially significant change in DNA fragmentation. However, the mean DNA sperm fragmentation of 30.3% is at the upper limit of normal. The authors hypothesize that this may reflect delayed transport of sperm. The reported effect on sexual dysfunction is not surprising. Further studies are needed to assess the potential clinical significance of this interesting observation.
Studies suggest exposure to bisphenol A may reduce fertility.
MedPage Today (11/20/08, Johnson) reported that "several new studies suggest that exposure to bisphenol A may reduce fertility in both men and women." For instance, Harvard University researchers led by Shelley Ehrlich, M.D., discovered an "association between men with higher levels of urinary bisphenol A (BPA) and poorer semen quality." Specifically, "90 percent of the men had urinary evidence of BPA exposure at a mean concentration of 2.4 mg/L," a finding that "is in line with a much larger study published in Environmental Health Perspectives." That study found "BPA in 93 percent of urine samples from a reference population of 2,517." In "Dr. Ehrlich's study, men with BPA concentrations above the mean of the study group had 3.5 times greater odds of having low sperm concentration, compared with men with exposure levels below the mean." Likewise, "the men with higher exposure had lower sperm motility and more abnormal sperm morphology." The "findings did not reach statistical significance, she said, but they are suggestive of what has already been shown in animal studies."
In vitro fertilization may be associated with increased risk of ovarian malignancies, research suggests.
MedPage Today (11/20/08, Johnson) reported that "in vitro fertilization is associated with an increased risk of ovarian malignancies, particularly borderline tumors (also called tumors of low malignant potential) -- but the absolute risk of the uncommon cancers remains small," according to findings presented at the American Society for Reproductive Medicine's meeting. This theory, explained researchers in the Netherlands, "hinges on the fact that superovulation, ovarian puncture, and high levels of gonadotropins cause increased damage to the ovary." In short, "the cumulative risk of ovarian tumors before age 55 is 0.45 percent in the general population," however, "this risk increases to about 0.71 percent after in vitro fertilization." These findings are based on a "mail questionnaire [that] was used to collect data on reproductive and lifestyle factors."
Antidepressants may impair fertility in men, researchers say.
New Scientist (9/24/08, Aldhous) reported, "Antidepressants taken by millions of men could be impairing their fertility by causing damage to the DNA in their sperm," according to research that will be presented "in November at a meeting of the American Society for Reproductive Medicine in San Francisco."According to the U.K.'s Telegraph (9/24, Alleyne), "The findings, published in New Scientist, once again throw the spotlight on the most commonly prescribed anti-depressants known as selective serotonin re-uptake inhibitors (SSRIs) that have also been linked to suicide in the past." For the study, Professor Peter Schlegel and Dr. Cigdem "Cori" Tanrikut of the Cornell Medical Center in New York City "gave 35 healthy men doses of paroxetine, a popular SSRI sold as Seroxat and Paxil, over five weeks and examined their sperm. Superficially, the men's sperm seemed healthy -- the amounts of sperm and semen, and the shape and motility of sperm, were all normal."
Varicocele embolization may be useful, but there are drawbacks, physician says.
In continuing coverage from a previous edition of the Daily Scope, HealthDay (7/23/08, Reinberg) reported that according to a study published in the journal Radiology, varicocele embolization can correct a "condition, called varicocele," which "is a network of tangled blood vessels in the scrotum which prevents the normal circulation of blood through the veins in the testicles," and can cause male infertility. The study involved "223 infertile men with at least one varicose vein" who "had healthy partners with whom they wanted to have a baby." The results showed that the procedure improved "sperm motility and sperm count...significantly." Dr. Hossein Sadeghi-Nejad, of the University of Medicine and Dentistry, New Jersey, "thinks this procedure can be useful." But, he added that "there are drawbacks to embolization. ... These include a steep learning curve to get used to doing the procedure and the danger of prolonged or misdirected radiation, especially if there are varicoceles on both sides of the scrotum."
Study suggests diet containing soy may decrease sperm count.
The BBC (7/24/08) reports, "A regular diet of even modest amounts of food containing soy may halve sperm concentrations," according to a study published in the journal Human Reproduction. Investigators examined "the diets of 99 men who had attended a fertility clinic with their partners and provided a semen sample." Researchers divided the patients "into four groups depending on how much soy they ate, and when the sperm concentration of men eating the most soy was compared with those eating the least, there was a significant difference." The results indicated that "[t]he 'normal' sperm concentration for a man is between 80 and 120 million per milliliter, and the average of men who ate on average a portion of soy-based food every other day was 41 million fewer."
According to the U.K.'s Guardian (7/24, Sample), "The apparent fall in sperm count is unlikely to make healthy men infertile, but some experts said it could have a significant impact on those already with lower than average sperm counts." Men must "produce fewer than 20 million sperm per ml" to be "regarded as clinically subfertile." Currently, "20 percent of young Europeans having a low sperm count, while levels of soya have risen steadily in the western diet since the 1940s because it is a cheap source of protein," and can be "found in two-thirds of manufactured food including biscuits, sweets, pasta and bread."
The U.K.'s Daily Mail (7/24/08) notes, "It is thought that soya compounds called isoflavones, which mimic the female sex hormone estrogen, are behind the effect," as "[a]nimal studies have [also] linked a high consumption of isoflavones with infertility." The men in this current study were "questioned...about consumption of 15 soya-based foods" such as "tofu, tempeh, soy sausages, bacon, burgers and mince, soy milk, cheese, yoghurt and ice cream, and soya products such as roasted nuts, drinks, powders and energy bars."
Highlighting details of the survey's results, WebMD (7/23/08, Hitti) reported, "Almost all of the men -- 90 percent -- had sperm concentrations that were within the normal range, and 42 percent of the men had normal semen analyses, which include sperm shape and motion in addition to sperm concentration." Furthermore, "[m]ost of the men -- 39 of them -- said they hadn't eaten any soy foods during the previous three months," while "[a]nother 18 men said they ate soy foods less than twice a month, 22 said they ate soy foods between twice a month and twice a week, and 20 said they ate soy foods at least twice a week."
HealthDay (7/23/08, Reinberg) added that "the researchers found that the link between soy and sperm concentration was stronger among overweight and obese men," because they "produce more estrogen than thinner men, and soy may increase those estrogen levels even further." And, "the link between soy and sperm concentration was strongest in men with higher sperm concentrations," as those "who have normal or high sperm counts may be more susceptible to soy foods than men with low sperm counts."