Scientists Say American Sperm Counts Are on the Decline

Sérgio Valle Duarte
, Wikimedia Commons // CC BY 3.0
IMAGE CREDIT: Sérgio Valle Duarte , Wikimedia Commons // CC BY 3.0

Concerned scientists say the sperm count of men in Western nations has dropped significantly since the 1970s, a change that may signify underlying public health issues. They described their findings in the journal Human Reproductive Update.

The international team of researchers analyzed data from 185 studies of semen samples collected from 1973 to 2011. The 42,935 donors hailed from 50 countries, which the scientists divided into two groups: "Western," including North America, Europe, Australia, and New Zealand; and "Other," including South America, Asia, and Africa.

At first glance, the results are both concerning and surprising. The last 40 years seem to have seen a slow but significant sperm slump among American and other Western men. The studies recorded an average annual decrease of 1.6 percent, yielding a total loss of 59.3 percent over the 38-year study period.

The same could not be said for men in the "Other" group, whose sperm count appeared to experience no significant change.

The authors of the current paper seem alarmed by their own findings.

"The fact that the decline is seen in Western countries strongly suggests that chemicals in commerce are playing a causal role in this trend," co-author Shanna Swan of the Icahn School of Medicine at Mount Sinai told New Scientist.

Swan and her colleagues did not look into any possible causes of the decrease but believe it could be a sign of overall declining health in the West.

"A decline in sperm count might be considered as a 'canary in the coal mine' for male health across the lifespan," they write. "Our report of a continuing and robust decline should, therefore, trigger research into its causes, aiming for prevention."

But before we all freak out, it's important to consider other elements that could be influencing these results. First, the sperm samples were not distributed evenly across all 50 nations. Only 16 percent of samples came from North America, and there were far fewer studies on the "Other" group overall; it's possible that sperm populations in South America, Asia, and Africa are experiencing the same slow decline.

Second, these studies measured sperm count—not sperm quality.

Third, and most importantly, even with the decrease, the global average sperm count remains within normal range. While a downturn means that more men's count may fall beneath ideal levels, we’re hardly facing a worldwide sperm shortage. Let's take this situation one drop at a time.

FDA Recalls Thyroid Medications Due to Contamination Risk


Hypothyroid medications manufactured by Westminster Pharmaceuticals have been recalled after it was discovered that one of the company’s Chinese suppliers failed to meet U.S. Food and Drug Administration (FDA) standards, CNN reports.

The oral tablets contain levothyroxine (LT4) and liothyronine (LT3), which are both synthetic hormones used to treat thyroid conditions.

The medicine was recalled as a precaution after it was discovered during a 2017 FDA inspection that the Chinese supplier in question, Sichuan Friendly Pharmaceutical Co., was not practicing good manufacturing practices.

However, patients with serious thyroid conditions shouldn’t throw out their pills just yet. No adverse effects from the medication have been reported, and the risk of not taking the medication outweighs the risk of taking a recalled pill.

According to the FDA, “Because these products may be used in the treatment of serious medical conditions, patients taking the recalled medicines should continue taking their medicine until they have a replacement product.”

For more information on the specific lots and products in question, visit the FDA’s website.

[h/t CNN]

A 'Zombie Gene' Might Be the Reason Elephants Rarely Get Cancer


When it comes to cancer rates in the animal kingdom, elephants are an anomaly. As Popular Science notes, cancer should be more common among larger species, but with elephants, that simply isn’t the case. Only about 5 percent of elephants die from cancer, compared to 11 to 25 percent of humans.

In a new study, published in Cell Reports, University of Chicago researchers found what’s believed to be the genetic source of elephants’ cancer immunity. Elephants, like all mammals, have a gene called LIF that is known to suppress tumors. Humans have one copy of this gene, but elephants have 10 copies, which have developed over 80 million years of evolution. However, only one of those copies, called LIF6, is functional in elephants.

The other LIF copies are essentially dead because they lack a specific piece of DNA to make them function. At some point during the evolutionary process, the LIF6 gene copy turned back on, but scientists don’t know why or when this occurred. This “zombie gene” helps kill mutated cells, in true Night of the Living Dead fashion.

“This reanimation of LIF6 occurred perhaps over 59 million years,” Joshua Schiffman, who studies cancer in elephants but was not involved in the study, told Popular Science. “That’s an amazingly long period of time for nature to modify and perfect an anticancer mechanism.”

Scientists aren’t yet sure how this could be applied to cancer research in humans, but they say it’s a promising start and a creative approach to the problem. While these findings are still fresh and need to be duplicated, it raises the possibility of creating a drug that mimics the function of LIF6.

[h/t Popular Science]


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