Monday, April 17, 2017

Lyme Disease is On the Rise

People who live in the Northeast are aware of Lyme disease; a baffling, debilitating, bacterial infection spread by bites from certain types of ticks.  Lyme disease is difficult to treat if not detected and treated early.  The forecast is for an increase in the number of cases of Lyme disease this summer. The reason is an increase in the population of field mice last year; mice, it turns out, are a preferred host of the ticks that spread the disease.

Cases of Lyme disease in the U.S. have tripled in the past 20 years, according to the Centers for Disease Control and Prevention (CDC).  For more on why that is, see the recent article in The New York Times.

How can you prevent becoming infected? Your best defense is to avoid being bitten by ticks.  If you are outside in a tick-infested area, be sure to check yourself carefully for ticks after coming back inside.  Most ticks won't actually bite you in the first 12-24 hours or so, so it pays to get them off of you as soon as possible.

Thursday, April 13, 2017

Updated Prostate Cancer Screening Guidelines

Just five years ago the U.S. Preventive Services Task Force (USPSTF) recommended that men 55-69 should be "discouraged" from having the PSA test to screen for prostate cancer (see this blog, May 27, 2012). At the time, the best evidence was that the risks of having a PSA test slightly outweighed the rewards. That's because the PSA test is not 100% accurate; sometimes it gives false positive results, meaning that the test indicates that prostate cancer might be present when in fact it isn't. According to the USPSTF, these false positive PSA tests were leading to biopsies (the next step in making a diagnosis), radiation, and sometimes even to surgeries for prostate removal, all of which carry some risk.

But just recently the USPSTF reversed course; now it recommends that men aged 55-69 should "have a conversation with their doctor" about the advisability of having the PSA blood test to screen for prostate cancer. Why the apparent about-face? Again, it's based on the best available evidence. The PSA test hasn't gotten any more reliable, but what has changed is what happens after a positive test result. Recent research has showed early, aggressive treatment after a positive PSA test isn't necessary and doesn't increase patient survival. That means that doctors can afford to wait, doing repeated PSA tests for years if necessary before recommending biopsies or treatment. As a result, the risks of having the PSA test (and everything that comes after) have declined to the point that the rewards now slightly outweigh the risks.

As before, the PSA test is not recommended for men over 70 (they're likely to die of something else before they would die of a slow-growing prostate cancer) or for men under 50 (prostate cancer is too rare in younger men for the test to be of much benefit).

Saturday, April 8, 2017

Home Genetic Testing and Risk Assessment Approved by the FDA

Back in 2013, a company called 23andMe (referring to the 23 pairs of human chromosomes) offered a genome testing service that promised to analyze a sample of the DNA in your saliva for over 300 alleles, many of which were associated with increased risks of genetic diseases. At the time, the FDA claimed that providing information about future risk of genetic disease was tantamount to offering medical device, and ordered the company to stop selling the kits for medical purposes (see this blog, Dec. 5, 2013).

For a time thereafter, 23andMe survived by selling its kits for "entertainment", i.e. to provide insight into ancestry for those who were interested. But it kept working on the medical angle. In 2015 the company went back to the FDA and was given approval to provide genetic information regarding allele "carrier" status for 36 genetic conditions, such as cystic fibrosis and sickle cell anemia, as long as the company didn't make any statements about the risks of developing a genetic condition as a result of the alleles (see this blog Nov. 3, 2015).

Still, the company kept working on the goal of being able to provide customers with valid risk assessment data. And apparently they did a pretty good job, for this week the FDA gave 23andMe permission to identify 10 telltale markers of genetic diseases, including Parkinson's disease and late-onset Alzheimer's disease, and provide information about the likelihood that the customer will develop the genetic conditions associated with these markers (my emphasis added). It's a big win for a small company, and a testament to the company's perseverance.

A word of caution, however, before you decide to have your DNA analyzed. You should know that you may not be able to keep the results of your home genetic test private under certain circumstances (see this blog, Mar. 13, 2017).

Sunday, April 2, 2017

A Texting-While-Driving Accident Claims 13 Lives

Here we go again. A lot has been written about the dangers of texting while driving, yet many of us just can't seem to resist the temptation. The death toll continues to climb.

Consider the most recent incident. Local sheriff's offices received several calls that a pickup truck was driving erratically on a two-lane highway west of San Antonio, Texas. One of the callers even recorded video footage of the truck. Although police responded to the calls quickly, they reached the pickup only after it had plowed head-on into a church van, killing 13 people. According to a Fox News report, the 20-year-old driver of the pickup truck (who survived the crash) said "I'm sorry, I'm sorry, I was texting."

Thirteen deaths is a lot to feel sorry for, especially when they could have been avoided so easily. And a lifetime of remorse is only part of what this young man will have to endure; what's the law going to do to him? I do truly feel sorry for him, because I'm sure he had no intention of harming anyone.

What's it going to take to get you to put down your phone while driving?