Roundup: Extreme Heat and Air Pollution Linked to Heart Attack Risk; Omega 3 Fatty Acids Benefit Lung Health; and More News

Study: Extreme Temperatures, Combined with Air Pollution, can Raise Risk of Fatal Heart Attack

A newly published study finds that extreme temperatures and high levels of air pollution can significantly raise a person’s risk of a deadly heart attack – especially when the two factors are combined. 

Researchers reviewed more than 202,000 heart attack deaths in Jiangsu province in China between 2015 and 2020. They found that the risk of a deadly heart attack nearly doubled in areas where temperatures were extremely high or low, or when there was a high level of particle pollution. The highest  risk was when extreme heat and high pollution levels were combined.

Older people and women seemed to be most vulnerable. Most deaths were among older adults with an average age of 77.6, and over half (52 percent) were 80 or older.

Particle pollution, also known as particulate matter, is a combination of tiny solid and liquid droplets that float in the air. It can come from various sources like dirt, dust, soot, smoke, and even emissions from power plants and vehicles. In this study, researchers focused on the smallest type of particle pollution called PM2.5. These particles are so tiny that they can't be seen and can easily enter our bodies.

The study, published in the journal Circulation, is drawing much attention as the U.S. and other parts of the world are going through record-breaking heat waves this summer. The American Heart Association also issued an extensive news release on the findings of the study.

Initially, researchers considered extreme temperatures to fall in a range between 82.6 to 97.9 degrees Fahrenheit. At that temperature over a two-day heat wave, the risk of dying from a heart attack was 18 percent higher, the study found. The risk was 74 percent higher during a four-day heat wave when the temperatures ranged from 94.8 to 109.4 degrees Fahrenheit.

The extreme temperatures were gauged based on the daily heat index -- also referred to as the “feels like temperature” --  for an area, which records the combined effect of both heat and humidity.

“Extreme temperature events are becoming more frequent, longer and more intense, and their adverse health effects have drawn growing concern,” said senior author Yuewei Liu, an association professor of epidemiology in the School of Public Health at Sun Yat-sen University in Guangzhou, China, in a statement. “Another environmental issue worldwide is the presence of fine particulate matter in the air, which may interact synergistically with extreme temperatures to adversely affect cardiovascular health.”

NIH: Major New Study Links Omega-3 Fatty Acids to ‘Maintaining Lung Health’

Omega-3 fatty acids are a type of polyunsaturated fat that can lower inflammation. They are needed to build brain cells and for other important functions. Previous studies have established that omega-3s can help keep your heart healthy and protect against stroke. A major new study funded by the U.S. National Institutes of Health (NIH) finds that omega-3 fatty acids appear “promising for maintaining lung health” as well.

Omega-3s are obtained from a healthy, plant-based diet. They are most abundant in fish and fish oil supplements. (Always consult with your doctor before taking supplements.)

The new study provides the strongest evidence to date of the importance of including omega-3s in your diet, “especially given that many Americans do not meet current guidelines,” states the NIH in a news release. Funded largely by the National Heart, Lung, and Blood Institute (NHLBI), part of NIH, the study results were published in the American Journal of Respiratory and Critical Care Medicine. 

“We know a lot about the role of diet in cancer and cardiovascular diseases, but the role of diet in chronic lung disease is somewhat understudied,” said corresponding author Patricia A. Cassano, Ph.D., director of the Division of Nutritional Sciences at Cornell University in Ithaca, New York, in a statement. “This study adds to growing evidence that omega-3 fatty acids, which are part of a healthy diet, may be important for lung health too.”

Previous studies have suggested that omega-3 fatty acids may help lung health, due largely to their anti-inflammatory actions. However, major studies about this link have been lacking, until now, says the NIH.

Researchers developed a two-part study investigating the link between omega-3 fatty acid levels in the blood and lung function. In the first part, they conducted a longitudinal, observational study involving 15,063 Americans from the NHLBI Pooled Cohorts Study — a large collection of NIH-funded studies looking at specific risks for chronic lung disease.   

The participants studied were generally healthy at the start of the study, with the majority showing no evidence of chronic lung disease. They comprised a racially diverse group of adults, with an average age of 56 years, and 55 percent were female. The researchers followed participants for an average of seven years -- and up to 20 years. 

The conclusion: Higher levels of omega-3 fatty acids in a person’s blood were linked to a reduced rate of lung function decline. The strongest links to healthy lung functions were found with docosahexaenoic acid (DHA), an omega-3 fatty acid that is found at high levels in fatty fish such as salmon, tuna, and sardines. 

“This large population-based study suggests that nutrients with anti-inflammatory properties may help to maintain lung health,” said James P. Kiley, Ph.D., director of the NHLBI’s Division of Lung Diseases, in a statement. “More research is needed, since these findings raise interesting questions for future prospective studies about the link between omega-3 fatty acids and lung function.” 

Gene Mutation May Explain Why Some Infected with COVID Never Develop Symptoms

They're called "super dodgers" -- individuals who never develop symptoms after contracting COVID-19. Researchers are trying to pinpoint what makes them immune to sickness from COVID. Now, a research team from the University of California at San Francisco (UCSF) say that super dodgers are "more than twice as likely as those who become symptomatic to carry a specific gene variation that helps them obliterate the virus," states a news release from UCSF.

In a study published in Nature, they offer the first apparent evidence that there is a genetic basis for asymptomatic COVID-19 infections. It's one of the first studies that may help solve the mystery of why some people can be infected without ever getting sick from COVID.

The study centers on the human leukocyte antigen (HLA), or protein markers that signal the immune system.

"A mutation in one of the genes coding for HLA appears to help virus-killing T cells identify COVID and launch a lighting attack," states the news release on the findings. The T cells of some people who carry this variant can identify COVID because of its resemblance to the seasonal cold viruses with which  the T cells are already familiar. This discovery may help formulate new drugs and vaccines to fight COVID variants, the researchers say.

“If you have an army that’s able to recognize the enemy early, that’s a huge advantage,” explained the study’s lead researcher, Jill Hollenbach, Ph.D., MPH, professor of neurology and a member of the Weill Institute for Neurosciences at UCSF, in a statement. “It’s like having soldiers that are prepared for battle and already know what to look for, and that these are the bad guys.”

The mutation – HLA-B*15:01 – is quite common, carried by about 10 percent of the study’s population. It doesn’t prevent the virus from infecting cells but it does prevent those infected from developing any symptoms. That includes a runny nose or even a barely noticeable sore throat, researchers add.

UCSF researchers found that 20 percent of study participants who remained asymptomatic after infection carried at least one copy of the HLA-B*15:01 variant, compared to 9 percent of those who reported symptoms.