Tag Archives: risk

Study in polluted Taiwan shows regular exercise still prevents high blood pressure

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People who regularly exercise are at a lower risk of high blood pressure, even if they live in highly polluted areas, found a new research, since the risk-benefit relationship between air pollution and physical activity is a major concern as more than 91% of people worldwide live in areas where air quality fails to meet World Health Organization (WHO) guidelines.

The paper published in the American Heart Association’s flagship journal Circulation, is based on a study of more than 140,000 adults without high blood pressure in Taiwan, who are followed for five years. Researchers classified the weekly physical activity levels of each adult as inactive, moderately active or highly active.

Researchers also classified level of exposure to fine particulate matter (PM2.5) as low, moderate and high. PM2.5 is the most commonly used indicator of air pollution. High blood pressure was defined as 140/90 mm Hg, though the American Heart Association 2017 Guideline defines high blood pressure as 130/80 mm Hg.

Exercise helps despite high pollution 

Study author Xiang Qian Lao, an associate professor at the Jockey Club School of Public Health and Primary Care at The Chinese University of Hong Kong in Shatin, said: “While we found that high physical activity combined with lower air pollution exposure was linked to lower risk of high blood pressure, physical activity continued to have a protective effect even when people were exposed to high pollution levels. The message is that physical activity, even in polluted air, is an important high blood pressure prevention strategy.”

Highlights of the study show that people who are highly active and exposed to low levels of pollution had a lower risk of developing high blood pressure, whereas those who were inactive and exposed to highly polluted air had a higher high blood pressure risk.

High risk levels

Each increase in PM2.5 level was associated with a 38% increase in risk of incident hypertension, whereas each increase in physical activity level lead to a 6% lower risk of hypertension, suggesting that reducing air pollution is more effective in preventing high BP.

Regardless of pollution level, people who exercised moderately had a 4% lower risk of high blood pressure than those who didn’t exercise. People who exercised at a high level had a 13% lower risk of high blood pressure than those who don’t.

The findings of this study are limited to air pollution because it only included people living in Taiwan, where ambient air was moderately polluted (the annual PM2.5 concentration was 2.6 times of the limit recommended by the World Health Organization).

‘Increased risk’ donor organs a tough sell to transplant patients

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Increasingly, transplant surgeons must initiate a tough conversation: explaining to patients what it means to accept an organ from a person who died from a drug overdose.

Organ donors who recently injected drugs, as well those who were incarcerated or had sex for drugs or money, are among a growing group of people classified as being at “increased risk” of an infectious disease such as hepatitis C or HIV.

But the label may not be doing patients any favors, according to a study about transplant trends and organ discard.

National organ transplant numbers show the United States Public Health Service’s increased risk of infection label (PHS-IR) is associated with hundreds of available organs going unused each year.

Despite the very low risk of disease transmission, patients in need are saying no to these organs, which account for 1 in every 5 deceased donor organs today.

Better guidance is needed for surgeons and patients on how much risk an increased-risk label actually presents to patients, says study author Daniel Kaul, M.D., director of the Transplant Infectious Disease Service at Michigan Medicine.

For a study published in Transplantation, Kaul led an analysis of Organ Procurement and Transplantation Network (OPTN) data showing organs labeled as increased risk are 7 percent less likely to be used than organs without the label.

“Overall utilization was less despite the extraordinarily low risk of disease transmission,” says Kaul, a professor of internal medicine at the University of Michigan. “The organ may have gone to the next person on the transplant waiting list, but it might not have been used at all.”

Also troubling, utilization rates of PHS-IR organs varied dramatically by geography. Depending on the donation service area, transplantation of available adult kidneys from increased-risk donors ranged from 20 to 100 percent, the analysis found.

“What that tells us is there may be a different understanding of true risk associated with this label — from one center to another and even within a center, from one organ specialty to another,” Kaul says.

If the increased-risk label did not exist, an estimated 313 more transplants could be performed in the United States each year, according to the study.

All organs identified as increased risk were less likely to be used with the exception of livers, for which transplant rates were nearly identical.

A possible explanation? Patients with liver failure may be too sick to say no. By comparison, a patient needing a kidney may continue dialysis and wait for another organ offer.

Favorable Odds

For most patients with end-stage organ failure, the immediate risk of dying is greater than the risk of getting an organ with an infection.

After rigorous screening, the risk of HIV or hepatitis C transmission from organ donation is low, at less than 1 percent — much less, for example, than the lifetime chances of dying in a motor vehicle accident.

Co-authored by Michael Volk, M.D., a former U-M physician now practicing in Loma Linda, California, and others, the study was published in a special issue of Transplantation that looked at reducing organ discard while safely maximizing organ availability.

Researchers analyzed criteria of donors from 2010 to 2013. The rate of nonutilization of increased-risk organs, the authors write, is likely now even higher because of a 2015 change to the PHS-IR criteria. Combined with the opioid epidemic, the change resulted in an increase in the proportion of organs with this label from 12 percent to 20 percent.

With little guidance about magnitude of risk, the stigma surrounding drug addiction can lead someone to turn down an organ that could save his or her life.

As of early October, about 116,500 Americans are waiting for an organ transplant.

Walking Like Ants Reduces Risk for Spiders: Study

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Humans aren’t the only actors on the planet. To avoid being eaten, some jumping spiders pretend to be ants, according to Cornell University research published in Proceedings of the Royal Society B.

Ants are aggressive at defending themselves: They are well-armed with bites, stings and formic acid. Ant-mimicking jumping spiders – Myrmarachne formicaria – in contrast, can’t do much more than run on their eight legs when attacked. Not surprisingly, insect predators tend to prefer spiders over ants, so appearing to be an ant confers significant protection.

Protective mimicry is a remarkable example of adaptive evolution: Moths can be colored like butterflies and grasshoppers may look like tiger beetles. While most mimicry studies focus on traits like color and shape, the researchers used multiple high-speed cameras and behavioral experiments to pinpoint how the spider’s movements mimic ants.

Ant-mimicking spiders walk using all eight legs but pause frequently to raise their forelegs to mimic ant antennae. When walking, they take winding trajectories of about five to 10 body lengths, which made them look like ants following pheromone trails. While the researchers could see what the spiders were doing thanks to high-speed cameras, many potential predators have slower visual systems, so that to them the mimics appear to be moving just like an ant would.

The researchers note that the findings “highlight the importance of dynamic behaviors and observer perception in mimicry.”