Scientific Research

The Hispanic Paradox: Why Are Some Ethnic Groups Living Longer than Others?

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In the U.S., we focus much attention on the health behaviors that can help us live a longer life: the “secrets” of centenarians and long-lived animal species such as the naked mole rat, the optimal amount of exercise to help us maintain muscle tone and independence, and the best eating style—whether it’s eating like we live in the Mediterranean, restricting calories or something in between. Yet part of the U.S. population seems to be unlocking the keys to increased longevity despite having risk factors traditionally linked to a shorter lifespan.

Approximately 55 million people in the U.S. are of Hispanic descent, and on average, they live two years longer than non-Hispanic whites. The Hispanic population in the U.S. has a lower overall risk of dying from 7 of the top 10 leading causes of death, including cancer and heart disease. Known as the “Hispanic paradox,” these positive health outcomes are often achieved among immigrant populations and in people with a greater likelihood living in poverty, having less education and health insurance, being overweight and several other factors that can negatively affect health. Additionally, rates of illness and death from other chronic conditions such as diabetes and liver disease remain higher among Hispanics than whites.

In an effort to boost longevity across ethnicities, scientists are studying how these unlikely circumstances—being high risk in certain areas, yet having a longer lifespan—can coexist. Theories include:

  • A study of lung disease in Hispanics suggests that their genes may protect against chronic obstructive pulmonary disease (COPD), an inflammatory lung disease, in addition to other factors.
  • Hispanics who come to live in the U.S. are generally younger than the average population and stay healthier.
  • With the exception of people from Puerto Rico, immigrants from Hispanic cultures smoke less than the overall population, leading to less lung disease. One study found that Hispanics in New Mexico are diagnosed less often with COPD than those living in other areas. Puerto Ricans, however, tend to smoke more and have a higher asthma risk.
  • A diet rich in beans and lentils, common in some Hispanic cultures, may curb inflammation to reduce chronic health risks.
  • Researchers think the strong family ties and support system seen in extended Hispanic families may play a role in staying healthy, particularly in the area of mental health.

Researchers continue to study Hispanic populations in the U.S. to try to find concrete reasons behind the Hispanic paradox to help them live even longer, healthier lives. During National Hispanic Heritage Month, we celebrate Hispanic heritage and culture in the U.S.—and all that these communities can teach us about living a healthier and longer life!

– Erica Roth and Stacy Brooks

Dog Gazing: Attachment between Hound and Human

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While walking through Santiago, Chile, you are likely to come across at least one of the countless wandering dogs that live on the busy streets. Homeless dogs are a normal part of Santiago’s culture. They are quick to make friends with anyone who offers a welcoming hand or food. They are not quick, however, to forget their friends. If you make a canine companion in this city, as my classmates and I did, it will probably remember you the next time you come down the street.

The feeling of attachment between the dogs and people of Santiago reminded me of the way a mother and her infant gaze into each other’s eyes. This simple, mutual act of love causes an automatic reaction in both the mom and baby, which increases the levels of oxytocin in the body. Oxytocin is a hormone that plays a major role in social bonding between mothers and infants and between romantic partners. The release of oxytocin promotes a feeling of social well-being and may prevent stress. Interacting with the local dogs in Chile made me wonder if this same sense of happiness and bonding occurs between dogs and people.

A research study looking at the bond between humans and dogs found a similar release—and increase—of oxytocin during social interactions, such as gazing, in both the animals and people. The dogs’ hormone levels also increased when people talked to and petted them. Scientists think this looped interaction reaction (bonding in both directions between pooch and person) may be a reason that humans were able to domesticate wild dogs in the first place. Dogs are one of the only animals known to fully recognize human facial features and expressions. This ability likely helps dogs and people communicate, love and take comfort in one another’s presence.

This mutual interaction is likely the cause of a quick, yet memorable, friendship between humans and dogs both at home and in places like the streets of Santiago. So next time you see a dog in passing, don’t be afraid to gaze into its eyes and form a quick friendship.

 

goff black white dogLogan Goff is an exercise physiology major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes studying nutrition, sports and research in the context of the Chilean culture. This is the final installment in a three-part series (read part one and part two) that spies physiology in this dynamic South American country.  

 

 

 

When Hormones Take Your Breath Away

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After a healthy childhood, my best friend suddenly started having breathing difficulties when she was 20 years old. The doctor diagnosed her with asthma. With the help of inhaled medications, she was able to control her symptoms. But a year later, the medications were no longer effective and she started having monthly, life-threatening asthma attacks. The severe attacks became more frequent a few days before her menstrual period, and the symptoms disappeared days after her period ended. At that time, I wondered if hormones could be to blame.

As a graduate student investigating the role of male and female hormones in lung inflammation, I know now that asthma can be a hormone-related health issue. Unfortunately, many people are unaware of this relationship. Hormones are chemicals that travel as messengers around the body through the bloodstream. They affect many bodily functions and play a large role in a woman’s life cycle from birth through puberty, adulthood, pregnancy and menopause. In proper balance, hormones help the body communicate and thrive. But sometimes hormone levels can be too high or too low, causing serious health problems, especially in people with asthma.

Although more young boys have asthma than girls, the pattern is reversed in adults: More women have asthma than men. During puberty girls begin to produce higher levels of the sex hormones estrogen and progesterone, which rise and fall throughout their menstrual cycle. About one-third of females with asthma report premenstrual-related asthma symptoms, which may lead to severe attacks. A research study of girls ages 8 to 17 found that those who started menstruating at earlier ages developed more severe asthma after puberty, perhaps because their hormone levels began to change earlier in life. Studies have shown that hormonal changes can disturb the airways and inflammatory responses in the lungs. As hormone levels go up and down, new blood vessels in the lungs form and disappear, affecting the lungs’ ability to take in oxygen. In addition, female hormones do not just cause breathing problems in women with asthma, but also in those who smoke or are overweight.

Researchers are working to discover how sex hormones affect the lungs in order to develop personalized treatments for asthma. Ideally, specialized treatments in the future will be gender-specific and take into consideration a person’s hormonal status.

Nathalie Fuentes OrtizNathalie Fuentes is a PhD candidate in the biomedical sciences program at Penn State College of Medicine. Her studies in Dr. Patricia Silveyra’s lab include the development of sex-specific therapies to treat lung diseases, sex differences in asthma-related lung inflammation triggered by ground-level ozone and the role of male and female sex hormones in lung disease. Nathalie is originally from Caguas, Puerto Rico.

 

 

Fact or Fiction: Does Coca Candy Prevent Altitude Sickness?

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This summer, I spent a month studying at the Universidad de los Andes in Chile. We visited the Atacama Desert, the driest non-polar desert in the world. It is nestled between two sets of mountains; during one of our excursions we hiked up the Andes Mountains to a village called Socaire, located at an altitude of around 11,000 feet above sea level.

Our site coordinator, physiology professor and “temporary mom,” Anne Crecelius, PhD, kindly offered us coca candy, hoping it might prevent the dizziness, nausea and headaches sometimes associated with altitude sickness. She had asked us to drink more water than we usually do, too, just in case anyone in our group responded badly to being so high up. Coca candy is made in part from coca leaves, a plant that local people have chewed on for thousands of years. Coca leaves contain chemical compounds called alkaloids, which have been shown to reduce hunger and calm the side effects of high-altitude travel.

The question remains whether coca really has physiological benefits. The research is mixed. Some studies, citing the uses of coca throughout history, claim that there are significant benefits to chewing coca leaves. They recount improved energy efficiency during exercise, boosted energy levels—similar to the effect of caffeine in coffee—and decreased thirst and appetite.

However, other researchers suggest that the effects of coca leaves are mostly psychological, similar to a placebo effect (using a fake treatment, or placebo, in a group of people to compare the effects with people using a real treatment). In some cases, the group taking the placebo will also see improvement in their condition.

Even if coca leaves do prevent altitude sickness symptoms, the candies we munched on did not contain enough coca to help much. But perhaps they were enough to create some sort of placebo effect in our group, as no one was sick, just a little out of breath. Nevertheless, we enjoyed the town, the candy and a snowball fight near a very old church. Who knew that a small town at high altitude could be so much fun? Most likely, the locals and generations of indigenous people, who also know of the power of coca.

Andrew KramerAndrew Kramer is an exercise physiology major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes, studying nutrition, sports and research in the context of the Chilean culture. This is the second in a three-part series that spies physiology in this dynamic South American country. Read part one.

 

Beer Does a Body Good?

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Bone is a living organ that constantly breaks down and rebuilds itself. As we get older, bone breaks down more and rebuilds less, which often leads to weaker bones over time. If we lose too much bone, we increase our risk of fracture and developing osteoporosis.

Women tend to have weaker bones and a faster rate of bone loss—particularly after menopause—than men. Approximately 50 percent of women in the U.S. over the age of 50 will break a bone due to osteoporosis. If the broken bone is in the hip, there is about a 20 percent chance that the individual will die within one year. Breaking a bone in our later years can significantly affect quality of life and the ability to live independently. Therefore, it is important to do everything we can to minimize age-related bone loss.

Lifestyle choices can help minimize bone loss, including:

  • following a healthy diet with enough calcium and vitamin D;
  • participating in regular physical activity; and
  • refraining from smoking.

Believe it or not, drinking a beer now and then may even help.

Researchers in Spain have discovered a link between beer consumption and bone health in women. They found that women who drank moderate amounts of beer—defined in the U.S. as up to one 12-ounce beer per day—had stronger bones than those who did not.

Beer contains two important nutrients that could be beneficial to bone health: phytoestrogens and silicon. Phytoestrogens are naturally occurring nutrients in plants that act similar to the hormone estrogen. Estrogen protects women from bone loss, but levels drop significantly after menopause. Estrogen deficiency is the primary cause of bone loss after menopause. Silicon is a naturally occurring mineral that may be used as a supplement to reduce bone breakdown and increase bone rebuilding in women with osteoporosis. Beer is one of the most plentiful sources of silicon in the Western diet.

It’s likely that the combination of phytoestrogen and silicon in beer helps limit bone loss. This finding has potentially important implications for bone health, although more study is needed.

It is also important to remember that drinking too much alcohol has many negative health effects, including reduced bone strength. Keep beer intake at a moderate level. That said Aug. 4 is International Beer Day. Drink a toast to healthy bones!

 

Kim HenigeKim Henige, EdD, CSCS, ACSM EP-C, is an associate professor and undergraduate program coordinator in the department of kinesiology at California State University, Northridge.

 

Spinal Cord Injury: Let’s Clear the Air(ways)

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The spinal cord is the information processing highway in animals (including humans) that have a backbone. In humans, the spinal cord contains nerve cells called motor neurons that control movement in the muscle fibers of the body, similar to the way a puppeteer controls the movements of a puppet.

About 17,000 people in the U.S. sustain new spinal cord injuries (SCI) each year, and roughly 300,000 people in the U.S. live with an SCI. Motor neuron damage in the spinal cord may lead to a variety of problems, including:

  • decreased mobility and independence;
  • loss of independent breathing;
  • injuries associated with using a wheelchair, such as pinched nerves and muscle strain;
  • partial or total inability to control the bowels and/or bladder; and
  • sexual dysfunction.

New research is addressing all of these important problems, but one area that is not as widely studied is airway clearance. Most of the time we can clear our airways ourselves through coughing and sneezing, but these actions become more difficult with SCI. Close to half of all people with SCI have damaged the motor neurons that control their diaphragm, the muscle that sits below the lungs and helps us breathe. As a result, people with SCI have an increased risk of potentially fatal airway infections such as pneumonia.

Fortunately, about 90 percent of these injuries are incomplete, meaning that some of the neurons still function. People with incomplete SCI have some sensation below the injury site and can often breathe on their own. We only need 10 to 20 percent of our diaphragm muscle to activate in order to breathe, but almost the entire muscle needs to be functional to cough and sneeze. When the motor neurons controlling the diaphragm are injured, the organ isn’t able to generate the forces necessary to clear the airways fully.

Over time, the neurons in the diaphragm that still function in an incomplete SCI may adapt to take over other jobs besides just breathing. This is called neuroplasticity. Neuroplasticity in the spinal cord is a valuable topic of research.  Researchers are looking for new ways to manipulate this process to help people with SCI learn new airway clearing methods which would likely reduce their health risks and improve their quality of life.

 

obaid-khurram-15978141Obaid Khurram is a PhD candidate in the biomedical engineering and physiology program at Mayo Clinic Graduate School of Biomedical Sciences. His research focuses on the neuromotor control of the diaphragm muscle, particularly after motor neuron loss or muscle weakness.

 

What Animals Can Teach Humans about Muscle Maintenance

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We all know the saying “use it or lose it.” Your muscles and nerves are no exception. When people are not active, whether it’s because of bed rest, spinal cord and nerve injury, or other reasons, two big problems arise. First, the muscles shrink by losing protein (a state called atrophy). Second, nerve cells have trouble firing electrical signals to communicate with the muscles. This combination can make it harder for people who are inactive to perform normal activities in their daily lives.

Unlike in humans, inactivity in other animals is not always such a bad thing. Certain animals in the wild need to stay inactive (dormant) to survive in their environment. During times of low food availability and harsh environmental conditions, ground squirrels, frogs, bats, turtles and bears may remain inactive. In the winter, this is called hibernation, and in the summer, it’s known as estivation. Quite often, these animals’ muscles are less active than normal or completely inactive for several months at a time. Some frogs can even survive under water during the winter without using their breathing muscles. Based on the idea of  “use it or lose it,” you might think that hibernating animals wouldn’t be able to run, jump, fly or even breathe normally after months of not using their muscles. Think again!

Understanding how animals immediately return to using their muscles and nerves normally after long stretches of dormancy is a major area of research. By learning how different animals dodge neuromuscular problems related to inactivity, scientists can figure out why human muscles and nerves are not as well-equipped. For example, hibernating animals activate genes that reduce the loss of muscle protein and use less energy during periods of inactivity to avoid atrophy. These discoveries have the potential to provide new treatment options for people who are confined to bed rest or who suffer nerve injuries that leave muscles unable to contract.

Animals have already solved many problems that plague humans, such as nerve and muscle inactivity. Research that compares animal and human function is an example of comparative physiology. Comparative physiology findings can help scientists make important discoveries that would not be possible if the cures hiding inside animals were overlooked.

Joe SantinJoe Santin, PhD, is a postdoctoral fellow at the University of Missouri-Columbia.

 

Can Exercising in Low-Oxygen Conditions Help Breast Cancer Survivors?

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Physical activity has been linked to a lower risk of developing several types of cancer, including breast cancer. Walking a few hours a week may even decrease the risk of a breast cancer recurrence as well as dying from the disease. The American Cancer Society currently recommends that people recovering from cancer should exercise at least 150 minutes per week.

But people with breast cancer often face a number of challenges to establishing a regular exercise program. Chemotherapy and radiation can affect heart and lung function, and about 60 percent of breast cancer survivors have reduced strength in their legs as a result of a loss of muscle mass. In addition, more than 80 percent of women gain weight after a diagnosis of breast cancer. These factors, along with fatigue from treatment, can prevent breast cancer survivors from being as active as they want to be.

Knowing that exercise is beneficial for people with breast cancer but that they face challenges, researchers at the University of Alabama at Birmingham (UAB) are looking at new ways to improve breast cancer survivors’ response to exercise. Their study compares the effects of exercising under low-oxygen conditions—similar to that seen at an altitude of 7,000 feet—with exercising in normal oxygen conditions at sea level.

Elite athletes sometimes train in mountainous areas—between 5,000 and 8,000 feet above sea level—to improve their performance. The air at high altitudes is thinner and contains less oxygen. Lower oxygen levels help boost the number of red blood cells that carry oxygen around your body. Exercising at high altitudes also lets you train harder without the added stress on your joints and muscles that occur at sea level.

While it is impractical to take cancer survivors to the mountains, UAB researchers are trying to bring the mountains to the patients During exercise sessions, participants wear a mask that is connected to a machine that controls the amount of oxygen they breathe in. This mimics the low-oxygen levels of a high-altitude workout.

The study is ongoing, so it is too soon to know how beneficial exercising under lower oxygen levels will be. However, the researchers predict that exercising in low-oxygen conditions will trigger a number of physiological changes that will let people with breast cancer be more active and improve their overall health. If the results of the study are correct, it may lead to new approaches to help breast cancer survivors lead a more active life.

 
John Chatham

John Chatham, DPhil, is a professor of pathology and director of the Division of Molecular and Cellular Pathology at the University of Alabama at Birmingham.

Like Father, Like Son (and Daughter): How Your Dad’s Past Affects Your Future

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What makes your father the best dad in the world? Maybe it’s his sense of humor or the times he has taken you to the movies or played catch in the yard. Or maybe it’s the fact that he made healthy lifestyle choices before you were born. Recent research suggests that your father’s health before you were conceived (preconception) may change the way your genes behave to affect your future health. It almost sounds like something out of a science fiction movie, but it’s real.

Studies tend to focus on the mother’s preconception health and the risks her baby might face later in life if she’s overweight. But a dad’s weight and early eating habits can also play a role, according to research published in the American Journal of Stem Cells. Researchers found that offspring of men who were obese before reproducing were more likely to have diabetes and be overweight. On the other hand, the researchers also found that fathers who had limited food resources in their early life caused genetic changes that protected their children—and even grandchildren—against cardiovascular disease.

Most people know that exercise is one of the healthiest lifestyle choices you can make to maintain your weight and keep your heart and even your brain healthy. However, research presented at the APS Integrative Biology of Exercise 7 meeting showed that offspring of men who exercised long term before conceiving had a higher likelihood of being obese and developing diabetes. This result was a huge surprise to the research team, but is it a reason to stop exercising? Not really. The study focused on how efficiently the body used energy on a high-fat diet. Limiting dietary fat and being active is still the way to go for most people.

Keeping stress levels low is also a good plan for dads-to-be. One study suggests that a man’s preconception stress may program his kids for mood disorders. Researchers found a pathway in the brain that transmits signals about stress hormones, and it may be passed down to the next generation.  If the signal is passed on to you, then your father’s stress levels could affect your predisposition for anxiety and depression.

These studies represent clues to learning how genetic material is transformed as it passes through generations. It’s also a reminder that following a healthy diet, staying active and maintaining mental health is important for everyone at every age.

Happy Father’s Day!

– Erica Roth

Putting Out Fires Hurts Firefighters’ Hearts

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As the temperature outside rises, our bodies make adjustments to keep our internal temperature constant to prevent us from overheating through a process called thermoregulation. This includes bodily functions such as sweating and widening of the blood vessels (vasodilation). When we sweat, perspiration evaporates from our skin to cool us down. When the blood vessels under our skin widen, our heart pumps more blood to our skin, which releases more heat from our inner body.

Our bodies are constantly working to hold a steady core temperature around 98-100 degrees Fahrenheit (F). This allows our organs to function properly. But when the temperature outside is extremely hot, our temperature can start to rise. A person with a body temperature above 104 degrees can develop heat stroke. This can cause dizziness, difficulty breathing, confusion, seizures or loss of consciousness. Brain and heart damage—sometimes permanent—can occur when body temperature climbs above 107 degrees F.

Too much summer heat can be unhealthy for everyone, but it can be especially dangerous to firefighters. The incidence of fires increases in the U. S. during the summer months. Firefighters fight almost twice as many fires in the summer compared to the rest of the year. On top of dealing with the extreme heat (sometimes over 700 degrees F!), these first responders face extreme physical exertion, mental stress and smoke inhalation on the job. All of these factors together can place firefighters in immediate danger of heat exhaustion, heatstroke and heart problems. In fact, firefighters are up to 136 times more likely to die from coronary artery or heart disease during or soon after they suppress a fire.

In a study published in Circulation last month, researchers may have uncovered several reasons why putting out fires puts firefighters at risk for heart disease. They discovered that a single, 20-minute session of fire simulation training—where healthy firefighters were exposed to physical activity in the extreme heat (about 755 degrees F)—was enough to injure their blood vessels, even though the firefighters’ core body temperature never reached above 101 degrees F. The problem: Although the firefighters’ bodies did keep their core temperature within a healthy range, their blood vessels did not relax properly immediately after the training. Also, as a result of the training, the firefighters’ blood clotted more easily. Damaged blood vessels and increased clotting of the blood can be very harmful to the heart and sometimes can lead to a heart attack.

This research shows us that even when we are able to keep our body temperature from getting too high, there are hidden dangers of being physically active in extremely hot temperatures. So keep your heart healthy this summer and don’t overexert yourself while outdoors!

Dao Ho, PhD

Dao H. Ho, PhD, is a biomedical research physiologist at Tripler Army Medical Center. The views expressed in this blog post are those of the author and do not reflect the official policy or position of the U.S. Department of the Army, U.S. Department of Defense or the U.S. government.