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

Scientists Say American Sperm Counts Are on the Decline

IMAGE CREDIT: 
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.

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Animals
Owning a Dog May Add Years to Your Life, Study Shows
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We've said that having a furry friend can reduce depression, promote better sleep, and encourage more exercise. Now, research has indicated that caring for a canine might actually extend your lifespan.

Previous studies have shown that dog owners have an innate sense of comfort and increased well-being. A new paper published in Scientific Reports and conducted by Uppsala University in Sweden looked at the health records of 3.4 million of the country's residents. These records typically include personal data like marital status and whether the individual owns a pet. Researchers got additional insight from a national dog registry providing ownership information. According to the study, those with a dog for a housemate were less likely to die from cardiovascular disease or any other cause during the study's 12-year duration.

The study included adults 40 to 80 years old, with a mean age of 57. Researchers found that dogs were a positive predictor in health, particularly among singles. Those who had one were 33 percent less likely to die early than those who did not. Authors didn't conclude the exact reason behind the correlation: It could be active people are more likely to own dogs, that dogs promoted more activity, or that psychological factors like lowered incidences of depression might bolster overall well-being. Either way, having a pooch in your life could mean living a longer one.

[h/t Bloomberg]

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Live Smarter
Not Sure About Your Tap Water? Here's How to Test for Contaminants
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In the wake of Flint, Michigan's water crisis, you may have begun to wonder: Is my tap water safe? How would I know? To put your mind at ease—or just to satisfy your scientific curiosity—you can find out exactly what's in your municipal water pretty easily, as Popular Science reports. Depending on where you live, it might even be free.

A new water quality test called Tap Score, launched on Kickstarter in June 2017, helps you test for the most common household water contaminants for $120 per kit. You just need to take a few samples, mail them to the lab, and you'll get the results back in 10 days, telling you about lead levels, copper and cadmium content, arsenic, and other common hazardous materials that can make their way into water via pipes or wells. If you're mostly worried about lead, you can get a $40 test that only tells you about the lead and copper content of your water.

In New York State, a free lead-testing program will send you a test kit on request that allows you to send off samples of your water to a state-certified lab for processing, no purchase required. A few weeks later, you'll get a letter with the results, telling you what kind of lead levels were found in your water. This option is great if you live in New York, but if your state doesn't offer free testing (or only offers it to specific locations, like schools), there are other budget-friendly ways to test, too.

While mailing samples of your water off to a certified lab is the most accurate way to test your water, you can do it entirely at home with inexpensive strip tests that will only set you back $10 to $15. These tests aren't as sensitive as lab versions, and they don't test for as many contaminants, but they can tell you roughly whether you should be concerned about high levels of toxic metals like lead. The strip tests will only give you positive or negative readings, though, whereas the EPA and other official agencies test for the concentration of contaminants (the parts-per-billion) to determine the safety of a water source. If you're truly concerned with what's in your water, you should probably stick to sending your samples off to a professional, since you'll get a more detailed report of the results from a lab than from a colored strip.

In the future, there will likely be an even quicker way to test for lead and other metals—one that hooks up to your smartphone. Gitanjali Rao, an 11-year-old from Colorado, won the 2017 Young Scientist Challenge by inventing Tethys, a faster lead-testing device than what's currently on the market. With Tethys, instead of waiting for a lab, you can get results instantly. It's not commercially available yet, though, so for now, we'll have to stick with mail-away options.

[h/t Popular Science]

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