Wednesday, October 26, 2016

Dishonesty May Be a Slippery Slope

Why is it that some people seem to lie or cheat consistently, with no apparent remorse? According to a report in Nature Neuroscience, it may be that they have been lying (or cheating) for so long that their brains' neural circuits have adapted to it, leaving them insensitive to their own dishonesty.

The researchers devised a research protocol in which volunteer subjects were put in a situation in which deliberate dishonesty was to their advantage, with no risk of detection. (As controls, other subjects were put in a situation in which only honesty was to their advantage.) Using magnetic resonance imaging (MRI), the researchers found that subjects who were dishonest showed a reduction in brain activity in the amygdala, the area of the brain associated with emotions. The degree of reduction of activity in the amygdala tracked with the history of dishonesty, suggesting adaptation. Even more startling was the finding that the rate of amygdala adaptation predicted the rate of escalation of subsequent dishonesty. It appears, then that dishonesty tends to increase with repetition.

Nearly everyone tells a little lie now and then ("That dress looks great on you!"). But when lying becomes a self-serving habit, it may become a habit that's hard to break. Think about that the next time you are tempted to cheat on an exam.

Tuesday, October 25, 2016

New Infant Safe-Sleep Recommendations to Prevent SIDS

Every year in the U.S., approximately 3,500 seemingly healthy infants die suddenly during their sleep.  A few deaths are clearly due to strangulation or suffocation, but most are lumped under the ill-defined heading of sudden infant death syndrome (SIDS).  The actual causes of many of these SIDS deaths are never identified clearly, though it is suspected that certain body positions and the type of bedding may contribute to many of the cases.  The highest risk is to infants between 1 and 4 months of age.

Recognizing that parenting is a new and potentially overwhelming experience for some parents, the American Academy of Pediatrics (AAP) has produced relatively easy-to-understand guidelines for parents that are designed to reduce the risk of SIDS.  Foremost among them; newborns should sleep in a crib or bassinet in the same room as their parents for at least six months, and preferably up to a year.  According to the AAP, room-sharing alone reduces the risk of SIDS by 50%.  The crib (or bassinet) should have a relatively firm, bare sleep surface that is free of toys, pillows, and, if possible, even blankets.  The newborn should be placed on his/her back.  If blankets are necessary for warmth, they should not restrict the baby's breathing or cause overheating.

For some reason, breastfeeding also apparently reduces the risk of SIDS, so it, too, is recommended. And it goes without saying that the infant should not be exposed to smoke, alcohol, or illicit drugs.

Simple, really.  Easy enough for even a new parent to understand, and that's the point. A little prevention goes a long way.

Thursday, October 13, 2016

Why is Myopia on the Rise?

Babies are born with "short" eyeballs, so shortly after birth they are unable to focus on near objects. During early childhood the eyeball elongates until both near and far images are in proper focus. At that point, eyeball elongation generally stops. However, in some people the eyeball continues to elongate beyond its ideal length. The result is the common condition known as myopia, in which the person now sees distant objects as fuzzy and out of focus. Fortunately, the condition is easily corrected with corrective lenses or Lasix surgery.

The incidence of myopia has doubled among young U.S. adults in the past 50 years. No one knows for sure why, though there are some interesting theories. One is that we spend too much time on our computers, cell phones, video games, etc., looking at screens up-close. Another theory is that we don't spend enough time outside in the sunlight. The second theory is supported by research in animals showing that a neurotransmitter called dopamine controls elongation of the eye; too little dopamine throughout childhood and young adulthood allows elongation to continue, leading to myopia. And, as it turns out, dopamine production is stimulated by sunlight.

The theory that the rise in incidence of myopia might be due to too little time in the sun is interesting, but no one is suggesting just yet that spend more time outside. For starters, we don' have any idea just how much time in the sun might be needed to prevent myopia. And we wouldn't necessarily want to trade myopia for skin cancer when myopia is so easily corrected.

Friday, October 7, 2016

Is There a Natural Limit to Human's Lifespan?

For at least a century, human life expectancy (how long a person can expect to live) has been steadily increasing. Some of the increase in life expectancy has been due to advances in medicine and improvements in health care delivery. An increased awareness of safety has also had an effect. And yet, we can all expect to die sometime. Is there a natural upper limit to the human lifespan?

Better understanding of the process whereby cells age and die has led some scientists to propose that the aging process could someday be slowed, to the extent that humans could live a lot longer than they currently do. That may be possible in the distant future. But a new report in Nature seems to suggest that in the absence of successful intervention with the aging process, the "natural" limit to the human lifespan is about 115 years.

The evidence is intriguing. Using the death records of the International Database on Longevity, the authors plotted the age of the oldest person to die in each year from 1968 to 2006. The age of the oldest person to die in any given year rose from 111 years old in 1969 to about to 115 years old in 1995. But since that time it has risen no further. Only three persons have ever lived longer than 115 years (call them exceptions). So unless those scientists who are working on delaying the aging process achieve a breakthrough soon, you better plan on having your affairs in order by the time you reach 115 years old.

Sunday, October 2, 2016

Health Impact of Air Pollution

The World Health Organization (WHO) has just released its latest figures for air pollution worldwide. According to WHO, one specific type of air pollution is associated with over 3 million deaths per year worldwide, not to mention the adverse health effects it produces. It's not ozone or other gaseous pollutants; it's PM 2.5 (particulate matter smaller than 2.5 micrometers in diameter). PM 2.5 is especially damaging to the lungs because it is small enough to be drawn into the deepest parts of the lung's airways. In industrial areas, PM 2.5 includes byproducts of diesel fuel combustion and black carbon, a component of soot. In rural areas and in some cities, naturally-occurring dust is a major contributor.

It might surprise you to learn that the highest levels of air-borne particulate matter worldwide are not necessarily in the most industrialized countries. According to the WHO, the highest levels of PM 2.5 are found in Northern Africa, the middle East, India, and parts of Asia. That's because in many of these areas, naturally-occurring dust is a major problem. In the United States, though, the most significant air pollutants are man-made. Major U.S. cities with the worst air are Chicago and Los Angeles; the states with the worst air are Illinois, Indiana and Ohio, in the industrial heartland. You can use WHO's interactive map to find the reported levels of particulate matter in your specific area. The full WHO report can be viewed here.

Admittedly, we're not likely to make much headway against the problem of naturally-occurring dust anytime soon. Nevertheless, adequate monitoring and reporting can at least warn citizens when their air quality is at its worst, and better education can help them take precautions. Man-made pollution is another matter; in addition to monitoring and education, progress can (and should) be made to reduce its occurrence, to the extent it is feasible to do so.

We can pay now to reduce exposure to bad air or we can pay later in health care costs. It's our choice.