Key genital measurement linked to male fertility

Source: MInsider Reuters: WASHINGTON, March 4 — When it comes to male fertility, it turns out that size does matter.

The dimension in question is not penis or testicle size, but a measurement known as anogenital distance, or AGD.

SOURCE:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2943951/bin/nihms220878f1.jpg

There is two alternative measures of AGD (anus to the posterior base of the scrotum [AGDAS], and to the cephalad insertion of the penis [AGDAP]).

AGDAS, but not AGDAP, was associated with sperm concentration, motility, morphology, total sperm count and total motile count (p-values 0.002-0.048).

NOTE: Explainatory words in this picture should be corrected as:

ASD = AGDAS,

AGD = AGDAP 

Men whose AGD is shorter than the median length — around 2 inches (52 mm) — have seven times the chance of being sub-fertile as those with a longer AGD, according to a study published on Friday in the journal Environmental Health Perspectives.

That distance, measured from the anus to the underside of the scrotum, is linked to male fertility, including semen volume and sperm count, the study found. The shorter the AGD, the more likely a man was to have a low sperm count.

This offers the prospect of a relatively simple screening test for men, said study co-author Shanna Swan of the University of Rochester Medical Center.

“It’s non-invasive and anybody can do it, and it’s not sensitive to the kinds of things that sperm count is sensitive to, like stress or whether you have a cold or whether it’s hot out,” Swan said in a telephone interview.

“If somebody’s got a short AGD, particularly if they have problems conceiving, I would say get to the infertility doctor, because the chances are good that something is wrong.”

To reach their conclusions, researchers measured the AGDs of 126 men born in or after 1988, a small but statistically significant sample, Swan said.

The study did not address what might cause certain men to have short AGD measurements.

But previous studies, published in 2005 and 2008, looked at the possible link between mothers who were exposed to chemicals called phthalates during pregnancy and the AGD of their infant and toddler sons.

Phthalates are a group of chemicals widely used in industrial and personal care products, including fragrances, shampoos, soaps, plastics, paints and some pesticides.

In these earlier studies, the scientists tested for the presence of phthalates in the pregnant women’s urine. They found that women who had high levels of phthalates in their urine during pregnancy gave birth to sons who were 10 times more likely to have shorter than expected AGDs.

Swan, who also co-authored the earlier papers, said they showed the correlation between prenatal phthalate exposure and shorter AGD.

The latest study does not address prenatal phthalate exposure directly, “but it does answer the question of why we should care about AGD,” Swan said. “And it does suggest that whatever is altering AGD is also altering sperm count.” — Reuters

Shorter Anogenital Distance Predicts Poorer Semen Quality in Young Men in Rochester, New York from the journal Environmental Health Perspectives

Jaime Mendiola, Richard W. Stahlhut, Niels Jørgensen, Fan Liu, Shanna H. Swan

Abstract Background: In male rodents, anogenital distance (AGD) provides a sensitive and continuous correlate of androgen exposure in the intrauterine environment and predicts later reproductive success. Some endocrine disrupting chemicals can alter male reproductive tract development, including shortening AGD, in both rodents and humans. Whether AGD is related to semen quality in human is unknown.

Objectives: To examine associations between AGD and semen parameters in adult males.

Methods: We used multiple regression analyses to model the relationships between sperm parameters and two alternative measures of AGD (anus to the posterior base of the scrotum [AGDAS], and to the cephalad insertion of the penis [AGDAP]), in 126 volunteers in Rochester, NY.

Results: AGDAS, but not AGDAP, was associated with sperm concentration, motility, morphology, total sperm count and total motile count (p-values 0.002-0.048). Men with AGDAS below (compared to above) the median were 7.3 times more likely (95% CI 2.5, 21.6) to have a low sperm concentration (<20×106/ml). For a typical study participant, sperm concentrations were 34.7 x106/ml and 51.6 x106/ml at the 25th and 75th percentiles of (adjusted) AGDAS.

Conclusions: In our population, AGDAS was a strong correlate of all semen parameters and a predictor of low sperm concentration. In animals, male AGD at birth reflects androgen levels during the masculinization programming window and predicts adult AGD and reproductive function. Our results suggest, therefore, that the androgenic environment during early fetal life exerts a fundamental influence on both AGD and adult sperm counts in humans, as demonstrated in rodents.

Citation: Mendiola J, Stahlhut RW, Jørgensen N, Liu F, Swan SH 2011. Shorter Anogenital Distance Predicts Poorer Semen Quality in Young Men in Rochester, New York. Environ Health Perspect :-. doi:10.1289/ehp.1103421

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2 Responses to “Key genital measurement linked to male fertility”

  1. Infertility « Dr Ko Ko Gyi’s Blog Says:

    […] Key genital measurement linked to male fertility (drkokogyi.wordpress.com) […]

  2. tim morgan Says:

    a very educated approach to blind faith.

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