may 2013 – News from the latest research

Less TV, MORE SPERM

Too much TV watching not only affects the mind—it can also impact sperm levels, according to a recent study in the British Journal of Sports Medicine.

Sperm quality has sunk over the past decades in most Western countries. One possible factor for this is an increase in sedentary behavior. Audrey J. Gaskins, a doctoral candidate at the Harvard School of Public Health in Boston, decided to put this claim to the test. Her research team collected sperm samples from 189 men aged 18–22 years and queried them on the time they spent exercising and watching television over the last three months, the average time it takes to create sperm.

On average, the men spent from five to 14 hours exercising and four to 20 hours a week in front of the television. Men who exercised more and spent less time in front of the television screen had higher total sperm count and sperm concentration. Those who exercised more than 15 hours a week had 73 percent higher sperm concentrations than those who only exercised five hours per week. Similarly, men who watched television more than 20 hours a week had almost half the sperm concentration of those who never channel-surfed.

“A more physically active lifestyle may improve semen quality,” the authors wrote, adding that spending too much time on the couch possibly increases scrotal temperature and leads to lackluster sperm.

—Jacqueline Ruttimann Oberst, PhD

Stop Smoking Now,
Despite WEIGHT GAIN

American smokers typically gain 9 to 11 pounds in the first year after they kick the habit, which can lead to an increased risk for cardiovascular disease (CVD). For diabetes patients, it can also lead to poor glucose control.

Weighing in on whether or not the increased risk for CVD dissipates over time, Carole Clair, MD, now at the University of Lausanne, Switzerland, analyzed the four-year weight gain seen in adults with and without diabetes who quit smoking and incidence of six-year cardiovascular events.

Smokers without diabetes experienced the most cardiovascular events— 5.89 for every 100 examinations. Recent quitters (≤ 4 years) had 3.22 such events and long-term quitters (> 4 years) had 3.06 events. Nonsmokers had only 2.43 events.

As expected, those with diabetes had higher numbers. Smokers in this group had 5.12 events, compared with 3.93 for recent quitters and 2.32 for long-term quitters. The overall trends suggest that these benefi ts off set the risk associated with weight gain.

“Cigarette smoking has short- and long-term cardiovascular effects that are reversible shortly after cessation,” the authors write in their article published in JAMA, citing examples such as a decrease in triglycerides and high density-lipoprotein cholesterol.”

—Jacqueline Ruttimann Oberst, PhD

Soak Up Some RAYS

New research suggests just one hour more of sunlight every day can have healthy rewards. Greek researchers led by Natalia Vallianou of the General Hospital of Athens Polykliniki, studied 490 healthy Caucasian adults over age 35 who lived in the urban area of Athens. Participants were questioned about their dietary and lifestyle habits, including daily amount of time spent outdoors. Biomarkers were measured after a 12-hour fasting period.

After allowing for several behavioral and biological factors including age, BMI, smoking habits, and hemoglobin, researchers reported that one hour more of daily sunlight exposure lowered the chances of having vitamin D deficiency, considered less than 20 ng/mL, by 70 percent compared to adequate levels. Those with vitamin D levels less than 20 ng/mL had an average of 8 daily hours of sun exposure compared with those with levels 20–30 ng/mL who had about 9.3 daily hours.

Even a slight increase in sunlight exposure could have beneficial effects on serum vitamin D concentrations and eventually on hemoglobin and inflammatory marker levels, providing a simple and inexpensive lifestyle intervention that promotes public health, writes the researchers in their paper published in the Central European Journal of Public Health.

—Glenda Fauntleroy

BISPHENOL A Linked
to Childhood Asthma

Add asthma to bisphenol A (BPA)’s ever-expanding list of health offenses, which include obesity, cancer, and infertility. More than 90 percent of U.S. children have trace levels of it in their urine.

This latest link came from a study published in the Journal of Allergy and Clinical Immunology. A research team led by Kathleen M. Donohue, MD, at Columbia University in New York City, measured levels of BPA in the urine of 568 inner-city mother-child pairs—from mothers during the third trimester of their pregnancy and from their children at ages three, five, and seven years. From five to seven years of age, the children also answered questions about their wheezing history over the previous year. Between ages five and 12 years, the doctors determined whether a diagnosis of asthma was warranted.

The authors found that BPA exposure at ages three, five, and seven years was associated with increased wheeze at ages five, six, and seven years, and increased asthma between ages five and 12 years. The children had roughly the same BPA levels as the average for U.S. kids, indicating that even low doses could trigger asthma. The finding could partially explain the skyrocketing rates of asthma that has recently happened worldwide, beginning in the 1980s. One out of every 10 U.S. children has been diagnosed with asthma, according to 2011 data from the U.S. Centers for Disease Control and Prevention. In black U.S. children, that rate is even higher—one out of every six.

—Jacqueline Ruttimann Oberst, PhD

ATHEROSCLEROSIS Not a Modern Ailment

Thought to be a modern plague related to our sedentary lifestyle, atherosclerosis also burdened our ancestors. A team led by Randall C. Thompson, MD, at Saint Luke’s Mid America Heart Institute of the University of Missouri-Kansas City School of Medicine, fi rst found evidence of the artery-clogging disease in 20 of 44 ancient Egyptian mummies. They then asked whether the disease affl icted other ancient societies, including those that had diff erent diet and genetic makeup to ancient Egyptians.

In a study named HORUS, from the ancient Egyptian deity of sun, war, and protection, the group conducted wholebody CT analysis of 137 mummies from four different ancient populations—76 ancient Egyptians; 51 Peruvians; five Ancestral Puebloans of the U.S. Southwest, and five Unangan of Alaska’s Aleutian Islands.

The findings, published in Lancet, revealed hardened arteries, indicated as calcium deposits or bright spots on the scan, in over a third—47 out 137—of the mummies. Atherosclerosis was present in all four populations: 29 (38%) of 76 Egyptians, 13 (25%) of 51 Peruvians, two (40%) of five Ancestral Puebloans, and three (60%) of five Unangan.

The results lend further credence to the authors’ earlier claim that emulating preindustrial man’s lifestyle would not necessarily avoid hardened arteries in today’s man. The popular “Paleo diet,” which patterns the eating habits of our ancestors by eating fish, grassraised meats, fruits, and vegetables and eschewing grains and refined sugars, may not be the antidote for heart disease after all. However, the scientists do recommend “eating a healthy diet and exercising,” said Thompson, whose team hopes to examine tissue and gene samples from these mummies to identify underlying risk factors for the disease. “We may have less control over getting atherosclerosis than some would have us believe, but that is all the more reason to control the risk factors that can be controlled,” he added.

—Jacqueline Ruttimann Oberst, PhD

Sleep Restriction’s ILL EFFECTS

Chronic sleep deprivation, besides being no fun at all, as parents and medical residents everywhere can attest, may lead to metabolic, heart, and cognitive problems, suggesting that these biologic processes operate on a temporal basis.

Recently, scientists led by Derk-Jan Dijk, BSc, MSc, PhD, FSB, at the University of Surrey, United Kingdom, investigated the mechanisms underlying the adverse effects that insufficient sleep wreaks on health.

In their paper first published online in Proceedings of the National Academy of Sciences of the United States of America, the researchers report that in 26 study participants allowed one week of 8.5 hours of sleep per day followed by one week of 5.7 hours of sleep per day, a whopping 711 genes associated with circadian rhythms (e.g., PER1), sleep homeostasis (e.g., PER2), oxidative stress (e.g., IL6), and metabolism (e.g., RORA) showed altered activity on whole-blood transcriptome analysis. Furthermore, they demonstrated that normally cyclic gene activity was disrupted, whereas many noncyclic genes began establishing daily patterns.

The researchers conclude that circadian disruption in metabolic and immune processes brought about by sleep deficit is possibly what leads to health problems. Future chronobiologic studies via the blood transcriptome will unlock additional pathophysiologic mechanisms, they add.

—Kelly Horvath

ARTIFICIAL PANCREAS Attends Summer Camp

The artificial pancreas is one step closer to leaving the hospital entirely. A study at a diabetes camp found that the device had less nocturnal hypoglycemia and tighter glucose control than a sensor-controlled insulin pump.

For patients with type 1 diabetes, intensive insulin therapy with an insulin pump is the gold standard for tight glucose control. Yet it runs the risk of the patients developing hypoglycemic episodes. These episodes, when glucose bottoms out, typically occur at night and could result in seizures, even death.

Artificial pancreas systems, the computerized linking of glucose sensors with insulin pumps, could theoretically counter these nocturnal hypoglycemic attacks. Recent studies with children, adolescents, and adults have shown these systems to do just that—in a hospital setting.

To imbue some real-world experience to these machines, Moshe Phillip, MD, at the Schneider Children’s Medical Center in Israel, led a study at three youth diabetes camps, one each in Israel, Slovenia, and Germany. These camps represented a “transitional” phase between the hospital setting and a child’s home. Their results are published in a recent issue of Th e New England Journal of Medicine.

For two consecutive overnight sessions, Phillip’s group randomized 56 type 1 diabetes patients 10 to 18 years of age into two groups. One group received treatment with an artificial pancreas on the first night and the usual treatment with a sensor-controlled insulin pump on the second. The other group had the reverse order of therapies on the first and second nights. Glucose levels and number of hypoglycemic events were recorded for both groups.

Patients experienced fewer hypoglycemic episodes and tighter glucose control on the days they used the artificial pancreas than the sensor-controlled insulin pump—definitely something to write home about.

—Jacqueline Ruttimann Oberst, PhD

Pancreatitis Risk Associated with EXENATIDE and SITAGLIPTIN

Type 2 diabetes patients on glucagon-like peptide 1 (GLP-1)-based therapies are at greater risk for acute pancreatitis than those not on these medications, claimed a recent JAMA Internal Medicine study.

GLP-1 mimetics, such as exenatide, and dipeptidyl peptidase 4 inhibitors, like sitagliptin phosphate, already had a spotty history. Both drugs caused acute pancreatitis in rodents and human studies remained inconclusive.

Sonal Singh, MD, at Johns Hopkins University, Baltimore, and his group decided to put this issue to rest. Th e team conducted a database study, zeroing in on the hospital records of 2,538 adults with type 2 diabetes aged 18 to 64 years who were admitted for acute pancreatitis or for other diabetes complications.

Patients who used sitagliptin or exenatide within the past 30 days or over two years had a two-fold greater chance of being admitted for acute pancreatitis than those on other diabetes drugs. Next, Singh’s group plans to see whether these acute episodes turn into chronic pancreatitis and pancreatic cancer.

—Jacqueline Ruttimann Oberst, PhD

Breastfeeding Does Not
Buffer Against OBESITY

For battling obesity, breast may not be best: A recent study from JAMA indicates that breastfeeding is unlikely to curb the obesity epidemic.

Breastfeeding confers many advantages to babies but its relationship with body composition and stature has so far remained tenuous. Babies suckle as much as the mother provides—too little and the mother may opt for formula which adds weight, too much and the mother ends up over feeding the baby.

Richard M. Martin, PhD, at the University of Bristol in England and his research team decided to base their study in a region previously known for low rates of breastfeeding—Belarus. They followed nearly 14,000 mothers and children who participated in an intervention trial to promote breastfeeding, measuring fat indices such as body mass index, waist circumference, skin thickness, and insulin-growth factor I, a hormone known to regulate height and weight.

Although infants who were breastfed gained more weight during their first three months of infancy than those who did not, at age 6.5 years, they showed no differences of these measurable signs of adiposity. Th e same was seen in these kids at age 11.5 years.

Don’t give up on breastfeeding just yet. Its other advantages are enough to justify public health efforts to promote it, claim the authors. The World Health Organization and the American Academy of Pediatrics advise exclusive breastfeeding for babies for the first six months.

—Jacqueline Ruttimann Oberst, PhD

rhGH THERAPY Improves Sleep

Patients with growth hormone deficiency suffering from nights of disturbed sleep can sleep better after treatment with recombinant human GH.

A new study appearing in the European Journal of Endocrinology evaluated 13 patients (ages 22–74 years) with untreated GH deficiency due to pituitary damage who had more slow-wave sleep and higher delta activity—leading to poor sleep quality and daytime sleepiness. Participants received a daily dose of rhGH therapy or placebo for two separate fourmonth observation periods. The rhGH was administered 30 minutes before bedtime and doses were sex- and age-specific according to standard treatment guidelines for patients with GH deficiency. After rhGH treatment, patients had a shorter sleep time than at the end of the placebo period (431 vs. 479 minutes, respectively).

“The decreased sleep duration induced by GH treatment in our patients can be interpreted as a recovery of the physiological mechanisms that control the sleep-wake cycle,” reports lead researcher Lisa Morelli, MD, of the Sleep, Metabolism, and Health Center at the University of Chicago. “After GH treatment, our patients needed less sleep and felt better during the daytime.” Morelli added that the study’s results suggest GH treatment may contribute to the improvement in quality of life experienced by the patients.

—Glenda Fauntleroy

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