Today's Health Tip will explore the validity of several medical issues that are commonly bandied about.  After reading each statement, decide whether it is true or false and then read on to learn more about the topic.

1. "Reading, sewing or doing other close work in dim light can damage your eyes."
In a survey on the topic, 71% of those polled had the misconception that eye damage would occur from reading under dim light.  Additionally, 66% erroneously thought that sitting too close to a television set would cause eye damage.  Reading in dim light can cause eye fatigue, but it will not cause eye damage.  When you think about it, for hundreds of years, people have been reading and working under dim light, such as oil or kerosene lamps.  While it is certainly preferable to perform these tasks with good lighting, aside from the fatigue that it creates, it does not do permanent damage.

2.  "Eating grilled meat can cause cancer."
Eating meat grilled well done or burned has been linked to several types of cancer, including colon and pancreatic.  The longer meat cooks at high temperatures, the greater the buildup of cancer-causing compounds called heterocyclic amines (HCAs)  This increased  risk of cancer is n
ot confined to grilled foods but is associated with pan-fried meats at high temperatures also.  Grilled vegetables, even well-done, do not appear to pose the same risk as overcooked meat.  You may be able to reduce your risk by precooking meats in the oven or microwave, and then finishing them on the grill for just a few minutes.

3.  "Eating chocolate will give you acne" 
This one has been debated back and forth for years.  Previously it was believed that acne development was related to factors such as hormones, heredity, and stress. Food, including chocolate, was not thought to cause it.  More recent research has found that people eating a diet with a low glycemic load (less sugar, higher fiber, etc.) were found to have healthier skin than those whose diet contained higher amounts of sugar.  This has led organizations, such as the American Academy of Dermatology, to recommend avoiding food with a high glycemic index (white bread, pasta, white rice, etc.) if acne is a concern.

4.  "Cracking your knuckles will give you arthritis."
There is no evidence that cracking knuckles causes damage, such as arthritis, to finger joints.  There is one report in the medical literature, however, of long-standing knuckle cracking resulting in injury to ligaments that support the finger joints. Additionally, people who habitually crack their knuckles have been found to have reduced grip strength as compared to people who did not crack their knuckles.
 
5.  "Undergoing anesthesia will cause your hair to fall out" 
The great majority of people undergoing general anesthesia notice no effect on hair growth or loss. There are two situations, however, in which receiving anesthesia may cause hair loss. The first is known as "pressure alopecia"--- hair loss in a specific area due to scalp pressure from the head lying in one position during prolonged anesthesia or postoperative recovery. The second is a condition known as "telogen effluvium".  This results in a more diffuse thinning of the hair on the scalp and is primarily seen following stressful events such as undergoing surgery, receiving general anesthesia or experiencing an illness with high fever.
That's all for this edition of Medical Fact and Fiction.  I hope that you found this entertaining as well as educational.  Stay tuned for the next episode.

Article Sources:
Safeguarding your sight, Harvard Health Publications
Chemicals in Meat Cooked at High Temperatures and Cancer Risk, National Cancer Institute
Acne, American Academy of Dermatology
Will Joint Cracking Cause Osteoarthritis?, WebMD
Hidden Causes of Hair Loss, WebMD

Content last reviewed by our Medical Director on 4-27-2016

Around six million people go to the emergency department each year with chest pain.  In many cases, the determination has to be made as to whether the chest pain is due to a relatively minor condition or to a life-threatening process.  Often this means making the distinction between heartburn (a gastrointestinal condition) and angina or heart attack (heart-related conditions), since these can all present with similar symptoms.

Heartburn, also called acid indigestion, is experienced by as many as 60 million Americans at least once a month. Heartburn is the most common symptom of gastroesophageal reflux (GERD), a disorder in which stomach acid "backs up" into the esophagus, the tube-like structure that connects the mouth to the stomach. Symptoms result when harsh stomach juices come in contact with delicate lining of the esophagus.  The most common features of heartburn are:

• A painful, burning sensation just below the breastbone or ribs
   
• Pain that develops after eating or upon reclining
   
• Improvement in symptoms when taking antacids or "acid blockers"
   
• A sour or bitter taste in the mouth and belching  

Angina is a symptom of coronary heart disease that occurs when the heart muscle is not being supplied with enough oxygen-carrying blood. It is usually described as a pressure or squeezing discomfort in the chest. This discomfort can also be felt in the arms (usually left), neck, or jaw.   A heart attack (myocardial infarction) occurs when blood flow to the heart is interrupted due to complete blockage of a coronary artery. This results in death of heart muscle. The pain caused during a heart attack or from a severe heartburn episode is sometimes so similar that sophisticated equipment may be required to tell them apart. The following are symptoms typical for heart attack:

• Chest discomfort in the center of the chest that lasts for more than a few minutes, or goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain.
   
• Discomfort in other areas of the upper body including one or both arms, the back, neck, jaw, or stomach.
   
• Shortness of breath, often occurring along with chest discomfort.
   
• Other symptoms may include breaking out in a cold sweat, nausea, or light-headedness.

 As with men, women's most common heart attack symptom is chest pain or discomfort. But instead of the classic chest discomfort women are somewhat more likely than men to experience certain "atypical" symptoms, particularly shortness of breath, nausea/vomiting, and back or jaw pain. An important distinguishing feature of coronary heart disease is that the discomfort often occurs with exertion or activity.  To confound things, however, heart attack as well as heartburn may occur after eating.  With severe chest pain, atypical symptoms suggestive of heart disease, or if chest pain is a new occurrence, it is best to leave the determination of the cause to the physician.

While a heart attack is a medical emergency, recurrent heartburn, particularly if associated with GERD is not entirely benign either. If left untreated, GERD can cause or contribute to a wide range of problems such as inflammation and ulcers of the esophagus (esophagitis). Some patients with esophagitis develop strictures (narrowing of the esophagus due to scar tissue) which can lead to problems swallowing food or pills. GERD can also contribute to asthma, pneumonia, hoarseness, chronic cough, abnormal functioning of larynx and dental problems. Medical attention should be sought if heartburn is associated with any of the following:

• Persistent heartburn after taking the full course of prescription or OTC medications (e.g. Prilosec, Tagamet, others)
   
• Severe hoarseness or wheezing
   
• Painful swallowing, especially with solid foods or pills
   
• Frequent nausea, vomiting or unanticipated weight loss
   
• Heartburn occurring several times a week or for more than a year

If you have warning signs of a heart attack, do not try to decide for yourself what the problem is—seek immediate medical attention.  A heart attack is an emergency. Call 9-1-1 if you think you (or someone else) may be having a heart attack. Prompt treatment of a heart attack can help prevent or limit lasting damage to the heart and can prevent sudden death. Remember that although both conditions make reference to the "heart", one is primarily a painful nuisance whereas the other represents a true medical emergency.

Article sources:
"Gastroesophageal Reflux Disease (GERD) in Adults" from The National Institute of Diabetes and Digestive and Kidney Diseases
"Heart Attack" from Family Doctror.org
What are the Symptoms of a Heart Attack" from the National Heart, Lung, and Blood Institute

Reviewed on April 20, 2016 by our Medical Director

X-rays done during dental visits have seemingly become a routine part of the examination. But did you know that the American Dental Association (ADA) in conjunction with the U.S. Food and Drug Administration (FDA) has developed guidelines for when and why they should be performed?
   
Why perform x-rays of teeth?   Dental x-rays can provide valuable information to help guide the dentist in providing the best care possible. Some of the advantages to the dentist as well as to patients include:

• Being able to detect areas of decay that are not visible on oral examination
   
• Identifying decay occurring beneath a filling
   
• Finding bone loss due to gum disease
   
• Revealing an abscess at the root of the tooth
   
• Allowing certain dental problems to be addressed at an early stage

Types of dental x-rays.  The three most common types of dental x-rays are the bitewing, periapical and panoramic.  Of these, the bitewing is the one most often performed.  The bitewing is performed by having the patient bite down on a piece of plastic with x-ray film.  These x-rays are designed to primarily view the molars and specifically look for decay between the teeth. A periapical x-ray provides an image of the entire tooth from crown to root.  These are particularly useful when evaluating for a cyst or abscess. Panoramic x-rays provide a view of the upper and lower teeth in a single view.  This type is particularly useful in evaluating children's tooth development or for the emergence of wisdom teeth.

Key recommendations from the ADA/FDA regarding dental x-rays in adults:

1. For new patients, an "individualized radiographic exam consisting of posterior bitewings with panoramic exam or posterior bitewings and selected periapical images", is considered to be appropriate.
    
2. In a new patient with evidence of dental disease or a history of extensive dental treatment, a “full mouth intraoral radiographic exam is preferred.”
    
3. For patients returning for dental evaluation, who have evidence of dental decay or who are at increased risk of developing cavities, a posterior bitewing exam at 6-18 month intervals" is recommended.
    
4. In return patients with no evidence of dental decay and no increased risk of developing cavities, "posterior bitewing x-rays at 24-36 month intervals" are advised.

Factors related to an increased risk of developing dental disease. Everyone is at risk of developing tooth decay, but a number of factors increase the likelihood of developing dental caries (cavities) including:

• Poor dental hygiene
   
• Foods that stick to teeth for a long time such as milk or sweets.
   
• Inadequate fluoride intake which is typically not present in bottled water.
   
• Worn fillings or dental devices.
   
• Dry mouth due to certain medical conditions, radiation to the head or neck, and taking medications that inhibit saliva production.
  
  
• Younger or older individuals who are more prone to developing cavities

It should be noted that these are recommendations only, with the final decision on when and why to perform x-rays left up to the dentist's clinical judgement. These guidelines vary somewhat in children, adolescents or in adults who do not have teeth. The ADA/FDA guidelines also state that the dentist should have dental x-rays performed only after reviewing the patient's health history and completing a clinical examination.

Additionally, measures should be taken to minimize radiation exposure by limiting the number of images produced, using "fast" speed film, and providing patients with radiation-blocking aprons and collars when appropriate.

Sources for article:
The Selection of Patients for Dental Radiographic Examinations from the FDA and ADA
American Dental Association Oral Health Topics---X-rays

Reviewed on April 13, 2016 by our Medical Director

Rather than considering the amount of protection that they afford, new sunglasses are often selected for their frames, the size of the lenses, or for a particular coating on the lenses. It is important to remember, however, that the most important job for sunglasses is to prevent damage to the eyes from the sun's harmful rays. Fortunately, with a little knowledge about Ultraviolet (UV) radiation and sunglasses technology, fashion does not have to take a backseat to safety.

What does UV protection indicate? The amount of UV protection is the single most important factor to consider when shopping for sunglasses. The three types of invisible high-energy UV rays are UVA, UVB, and UVC.  At present, UVC waves are being blocked by the earth's ozone layer and are not a factor in causing eye damage. UVA and UVB rays are the ones that are most damaging to the eyes. Fortunately, even inexpensive sunglasses can provide complete protection against these rays. Always select sunglasses with labeling that indicates that they block "99 to 100% of UVA and UVB rays". If this is not indicated on the label, pass them up.

What other features provide help protect the eyes? In general, larger lenses provide more protection than smaller lenses. In addition, "wraparound" styles of sunglasses help prevent sunlight from reaching the eye from the sides of the glasses.

Why are some sunglasses more expensive than others? This has to do with a number of factors, such as the optical clarity of the lenses, the exclusivity of the frames, or the special coatings that are applied to the lenses. So long as they are both providing complete UV protection, however, a twenty-dollar pair of sunglasses can be just as protective as a two-hundred dollar pair.  Typically, however, the more expensive brands of sunglasses, include a higher quality lens capable of producing a clearer, sharper, image with less distortion.

Does being darker mean that the lens is more protective? How deeply tinted the lenses of sunglasses has no bearing on the amount of protection that they provide. Lightly tinted sunglasses that block 99 to 100% of UV rays are more protective than a darker pair with a lower UV rating.

What about the protection provided by Transitions® sunglasses?  Transition lenses are also known as "photochromic lenses" since they darken on exposure to UV light. Their manufacturer indicates that they provide 100% UV protection whether they are clear or as dark as regular sunglasses. Not all manufacturers of photochromic lenses offer complete UV protection, so be sure to check the product label.

What is the advantage of polarized glasses? Polarized glasses are best for preventing glare, particularly when near the water. That makes them particularly useful when fishing or boating. They can also prevent eyestrain from glare when driving. In most cases, polarized sunglasses also provide complete UV radiation protection, but this is worth confirming before purchasing.

Are certain lens colors better than others? As long as the lenses are providing complete protection against UV radiation, the American Academy of Ophthalmology indicates that color is a matter of personal preference. Gray, green, or brown lenses are the most popular shades of lenses for sunglasses.

What about shaded lenses? These are popular with many designer sunglasses manufacturers. They are also known as "gradient lenses", since they are permanently shaded from top to bottom or top and bottom toward the middle. This variation in tinting of the lens does not affect the UV protection and can be as protective as sunglasses with a uniform tint.

From this discussion, it becomes clear that eye protection from the sun and stylishness can co-exist. The most important issue is to make sure that the sunglasses you choose provide complete protection against UV rays. Be aware that even though contact lenses can provide some UV protection, sunglasses should be worn outside since contacts do not cover the entire eye. Also, considering the amount of time that children spend in the sun, they should wear UV-protective sunglasses also.

Sources for article:
How to choose the best sunglasses from the American Academy of Ophthalmology
Guidance Document For Nonprescription Sunglasses from the U.S. Food and Drug Administration

Guidelines published by the U.S. Preventive Services Task Force recommend that adults ages 50-75 who are at average risk for the development of colon cancer can reasonably be screened by one of three methods: 1) fecal occult blood testing, 2) sigmoidoscopy, or 3) colonoscopy.  Fecal occult blood testing involves the use of "cards" onto which a stool sample is placed and tested for the presence of blood which may not be readily apparent. Sigmoidoscopy is a more limited version of colonoscopy in which the lower portion of the colon is viewed using a flexible fiber optic “scope”.  Colonoscopy, in which the entire colon is directly visualized, is currently considered to be the “gold standard” for colorectal cancer screening.
 
In 2014, an alternative to these screening methods was approved by the U.S. Food and Drug Administration (FDA) as well as by the Centers for Medicare & Medicaid Services. This screening method is called Cologuard, and like the fecal occult blood test, is stool-based.

How does Cologuard work?  The test detects microscopic amounts of blood in the stool as well as detecting altered DNA that could have been caused by colon cancer or pre-cancer.  Cologuard is available only by prescription.  It is performed at home by collecting two samples of stool that are sent to a laboratory for analysis.

Who should consider having this test?  Screening rates for colon cancer fall below the targets set by the U.S. Centers for Disease Control. Reasons for this include the expense and typically unpleasant nature of preparation for colonoscopy and the requirement that fecal occult blood testing must be repeated on an annual basis.  Cologuard represents an alternative for someone who would otherwise not undergo colon cancer screening due to these and other reasons. It should be noted that the test is intended for people who are at average risk for developing colon cancer. It is not currently recommended for those at increased risk, such as someone with a family history of colon cancer or with an inflammatory condition affecting the colon such as ulcerative colitis. People at higher than average risk may require more frequent or a different method of screening.

How accurate is Cologuard?   Prior to FDA approval, Cologuard was evaluated in a large clinical trial involving more than 10,000 people.  Cologuard was found to detect 92 percent of colorectal cancers as compared to 74 percent of cancers detected using a home-based stool test (Fecal Immunochemical Test--FIT).  Cologuard also detected 42 percent of precancerous lesions compared to a 24 percent detection rate with the FIT test. One downside of Cologuard testing is that is has a higher likelihood of a false positive result.  This means that the test can come back positive even in the absence of disease.  In these cases, follow-up testing with colonoscopy is recommended.

Will this test replace other methods of screening?   Colonoscopy remains the best single test for colorectal cancer screening. Not only is the entire length of the colon directly visualized, but the doctor also has the ability to perform biopsies and remove polyps during the procedure.  As mentioned previously, Cologuard’s main application may be to provide people who are unable or unwilling to undergo other forms of testing with a reliable screening method. As of now, Cologuard is listed as an acceptable method of screening for colorectal cancer by the American Cancer Society and as an “alternative” method of screening by the USPSTF.

How much will Cologuard cost?  Cologuard is a very sophisticated test that will not come cheaply. This is primarily due to the component of the test that looks for abnormal DNA. An estimated cost is somewhere in the $500-650 range.  This is much more expensive than the basic stool test costing in the $5-10 range but considerably less than a colonoscopy at around $6000 per procedure.
Article sources:

1. USPSTF recommendations regarding colorectal screening
2. FDA Press Announcement regarding Cologuard
3. Cologuard by Exact Sciences