Pages

Sunday, April 28, 2019

Lyme disease 10 times more common than thought

It’s easy to think of heart disease and stroke as an almost inevitable part of aging in a developed country like the United States. After all, they are our leading causes of death and disability. But the truth is that these are largely preventable conditions.

New estimates from the Centers for Disease Control and Prevention (CDC) indicate that one-quarter of all deaths from heart disease and stroke are preventable. And that is almost certainly an underestimate.

According to the report, published online yesterday in Morbidity and Mortality Weekly Report, among American adults under age 75, approximately 200,000 of deaths caused each year by heart disease, stroke, and high blood pressure (hypertension) are preventable. Surprisingly, more than half of those preventable deaths occurred among individuals under age 65.

During a press conference to present the study results, CDC director Dr. Tom Frieden said, “As a doctor, I find it heartbreaking to know that the vast majority of people who are having a heart attack or stroke, under the age of 65 in particular, and dying from it didn’t have to have that happen.”

It’s possible that the rate of preventable deaths is lower among those over age 65 because they are covered by Medicare, and so may be more likely to see doctors and receive preventive treatment.

Other factors also influenced the rate of preventable death. Sex is one: men were twice as likely to die from a preventable heart attack or stroke as women. Race and ethnicity also matter: blacks were twice as likely to die from a preventable heart attack or stroke as whites.

Geography is another influence. “Longevity may be more likely to be influenced by your ZIP code than by your genetic code,” said Dr. Frieden. Preventable deaths were more common in southern states, as shown by the map below.
Rates of avoidable deaths due to heart disease, stroke, and high blood pressure by U.S. county, 2008 to 2010. (Source: Centers for Disease Control and Prevention)

Rates of avoidable deaths due to heart disease, stroke, and high blood pressure by U.S. county, 2008 to 2010. (Source: Centers for Disease Control and Prevention)

The good news is that the rate of preventable deaths declined 29% from 2001 to 2010, the last year for which there are complete statistics.
An underestimate

The CDC came up with its estimates using mathematical modeling. It essentially identified “avoidable deaths” as those occurring among men and women under age 75 who had been diagnosed with heart disease, stroke, or high blood pressure. Such people, so the thinking goes, can be treated to prevent the condition from killing them.

Preventing these conditions in the first place could lead to even greater reductions. Harvard School of Public Health researchers followed nearly 85,000 women in the Nurses’ Health Study, all free of cardiovascular disease, cancer, and diabetes at the study’s start in 1980. After 14 years of follow-up, 1,128 had experienced a heart attack or died of heart disease. Women with a healthy lifestyle (nonsmoker, healthy body weight, moderate-to-vigorous physical activity an average of at least half an hour per day, and a healthy diet) were far less likely to have had a cardiovascular problem than women who didn’t. In fact, the researchers estimated that 82% of the coronary events in these women could be attributed to aspects of an unhealthy lifestyle. The study was reported in the New England Journal of Medicine.
Do-it-yourself approach

No matter what your age and how good things look today, your future risk of heart disease, stroke and other related diseases is high. It’s true for all of us.

That’s why it’s so important to do all you can to lower your risk:

    Don’t smoke. If you smoke, it’s never too late to quit. Your risk of a heart attack starts to decrease within weeks of quitting.
    Aim for or maintain a healthy weight.
    Take steps to help keep your blood pressure in the healthy range. Eat a diet rich in fruits and vegetables and limit salt intake. If lifestyle changes aren’t enough to do the job, there are a number of medicines that work.
    Reduce your consumption of saturated and trans fats. This will help improve your LDL (bad) cholesterol level. Instead use more olive oil and other unsaturated oils. Some people may also need a statin drug to lower LDL.

Over the next 10 years, we have the knowledge and means to greatly increase the number of preventable deaths from heart disease, stroke, and from many other diseases as well. As a nation we could take a huge step forward by becoming more physically active and adopting other healthy lifestyle changes. No time in your busy schedule for a long workout? No problem. Combining brief bouts of moderate to vigorous exercise over the course of the day also add up to good health, an interesting new study suggests.

Most guidelines—such as those of the American Heart Association—call for at least 30 minutes of moderate plus vigorous physical activity five days a week in bouts of at least 10 to 15 minutes. Some experts call for even more. Exercise specialist Aaron Baggish, MD, assistant professor of medicine at Harvard-affiliated Massachusetts General Hospital, says people wishing to be in tip-top shape should strive to get in an hour of exercise five days a week.

Many people have trouble finding that kind of time. Is it possible to cram exercise into shorter bursts?
Every minute of exercise counts

To find out how we can squeeze more exercise into our lives, researchers led by Jessie X. Fan, PhD, professor of family and consumer studies at the University of Utah, analyzed data on 4,511 U.S. adults age 18 to 64 collected by the National Health and Nutrition Examination Survey. Fan’s team identified people who accumulated at least the minimum recommended amount of exercise, but in shorter-than-recommended bouts of 10 minutes or fewer. They found that people who accumulated exercise in very short bursts and who got at least 30 minutes of moderate activity five days a week had a lower body mass index (BMI, a measure of weight versus height) than those who didn’t get 150 minutes of exercise a week.

“We are talking about a brisk walk at three miles per hour, or anything of higher intensity like going up and down a flight of stairs or jumping rope,” Dr. Fan says. “This doesn’t change the recommendation of 150 minutes of brisk exercise a week or 30 minutes on five days. It is just a different way of accumulating this.”

The findings reinforce suggestions that people should look for simple ways to get short bouts of exercise: for example, by parking at the far end of the lot and walking briskly to the entrance, by taking the stairs quickly instead of riding the elevator, or by plugging in your earbuds and dancing energetically to a favorite song.

If you are a professional working a desk job at a computer, set a timer and every half hour get up and do a minute or two of something energetic, Dr. Fan suggests.

The Fan study isn’t the first to suggest that a little exercise is better than none, and that accumulating shorter bouts of exercise is better than not missing exercise days due to lack of time for a longer workout.

“This is a story that has been developing over some time,” says Dr. Daniel Forman, associate professor of medicine at Harvard-affiliated Brigham and Women’s Hospital. “Now people have no excuse for not exercising.” The 30,000 cases of Lyme disease reported to the Centers for Disease Control and Prevention (CDC) each year are just the tip of the iceberg. According to a new CDC estimate, more than 300,000 Americans are diagnosed with the tick-borne disease each year. The new number was presented at the 2013 International Conference on Lyme Borreliosis and Other Tick-Borne Diseases, being held in Boston.

Although the new numbers may be an overestimate, they still provide a clearer picture of the impact of Lyme disease in the United States, says Dr. Robert H. Shmerling, a rheumatologist at Beth Israel Deaconess Medical Center and associate professor of medicine at Harvard Medical School.

Instead of relying mainly on cases reported by doctors, a standard public health approach, CDC researchers are trying to get a more complete picture of Lyme infections by sifting through health insurance claims, analyzing data from clinical laboratories (which do the tests necessary to diagnose Lyme disease), and surveying the public for self-reported Lyme disease.

“We know that routine surveillance only gives us part of the picture, and that the true number of illnesses is much greater,” said Paul Mead, M.D., chief of epidemiology and surveillance for CDC’s Lyme disease program, in a statement. “This new preliminary estimate confirms that Lyme disease is a tremendous public health problem in the United States, and clearly highlights the urgent need for prevention.”

Although Lyme disease has been diagnosed in almost every state, most cases reported to the CDC are in the Northeast and upper Midwest—96% of cases come from 13 states.
The aftermath of a tick bite

Lyme disease is a zoonotic disease, meaning a disease spread between animals and humans. It is caused by a bacterium called Borrelia burgdorferi, which lives in mice and deer. These corkscrew-shaped bacteria, called spirochetes, get into black-legged ticks when they feed on an infected animal. They migrate to the tick’s salivary glands, and, if the tick bites a person, are injected into the bloodstream. An excellent illustration by The Boston Globe depicts this life cycle.

In some people, the immune system destroys the bacteria before they can do any damage. In others, they grow and multiply, causing an infection. Symptoms include a bull’s-eye-shaped rash, fever, headache, and fatigue. Treatment with antibiotics can usually prevent any short- or long-term repercussions, says Dr. Shmerling.

If the infection isn’t treated, problems can develop in other parts of the body, including the joints, heart, and nerves. It can also cause arthritis that persists months or years after the tick bite.

Some people with Lyme disease and some doctors have argued that Borrelia burgdorferi can somehow evade courses of antibiotics and become a chronic infection that needs long-term antibiotic treatment—even though conventional antibody tests are negative. Chronic Lyme disease has been blamed for causing pain, fatigue, muscle aches, loss of memory and thinking skills, and a host of other problems.

A Boston Globe series, “Bitten By Uncertainty,” has been exploring this controversial side of Lyme disease.
Prevention is key

Like most communicable diseases, Lyme disease is largely preventable, says Dr. Shmerling. Avoid being bitten by a blacklegged tick (also known as a deer tick) and you won’t get Lyme disease. There are two main ways to do that—stay out of brush and high grass in and around wooded areas, or get out in nature and protect yourself. Here are six tips for protecting yourself from ticks, adapted from the Connecticut Agricultural Experiment Station’s comprehensive handbook about tick management.

1. Wear light-colored clothing. Light colors make ticks easier to spot, especially tiny deer tick nymphs.

2. Tuck your pants inside your socks. It may not be a flattering look, but it creates a physical barrier against ticks.

3. Use insect repellent. Most of the chemicals that repel mosquitoes are somewhat effective against ticks, although it may take a heavier concentration of DEET—between 30% and 40%—to really keep them away. Permethrin is a stronger chemical that kills ticks as well as repels them. Products containing permethrin should be sprayed on clothes, not on the skin. Picaridin repels mosquitoes and other insects but not ticks.

4. Stay in the middle of the path (or fairway). Ticks can’t fly or jump, so they can only get on you if you come into contact with the kind of environment they live in: moist, often shady, wooded areas, with leaves, low-lying plants, and shrubs.

5. Think sunny. Ticks don’t do well in dry, open areas. Lawn furniture and playground equipment should be set back from the edge of wooded, shady areas. If you’re picnicking, pick a patch of well-tended lawn or some open ground.

6. Inspect yourself and your children (and your pets), especially the legs and groin. Ticks usually get picked up on the lower legs and then climb upward in search of a meal. The odds of contracting Lyme or other tick-borne disease are minimized if a tick is removed soon after it’s attached, and there’s no risk if it’s still crawling around. The shower is a good place to conduct a tick check. Feel for any new bumps on soaped-up skin.

And if you do get bitten by a tick, remove it using the method recommended by the CDC: Use a pair of fine-tipped tweezers to grasp the tick as close to the skin as possible. Then pull it out with a steady motion. Once the tick has been removed, clean the skin with soap and water. Dispose of the tick, which is probably still alive, by placing it in alcohol or flushing it down the toilet. Don’t fall for “home remedies” like covering the tick with Vaseline or touching it with a just-blown-out match.

No comments:

Leave a comment