Monthly Archives: November 2015

People with ‘social jetlag’ may have higher risk of chronic illness, study suggests

Did you have a long sleep-in last weekend?

If you did, you may be among the estimated two-thirds of Americans who regularly experience “social jetlag” — a shift in their weekend sleep schedule to one that is more aligned with their body’s natural, circadian rhythms.

For most Americans, that shift means waking up later than they do on weekdays.

Social jetlag is difficult to avoid in today’s 9 to 5 (or 8 to 6?) working world. But, unfortunately, there is mounting evidence that it is bad for our health.

The latest piece of evidence comes from a study published last week in the Journal of Clinical Endocrinology & Metabolism. In that study, researchers from the University of Pittsburgh found a strong association between social jetlag and an increased risk of metabolic changes in the body that can contribute to obesity, type 2 diabetes and heart disease.

Scientists have long known that shift workers are at greater risk than normal daytime workers of developing chronic diseases such as diabetes and heart disease. This new study is the first one, say its authors, to show quantitatively that social jetlag — which essentially involves traveling back and forth each week between two time zones — can also lead to unhealthy metabolic changes linked to those diseases.

Study details

For the study, the researchers studied data collected from 445 healthy men and women aged 50 to 54. Each worked for at least 25 hours a week outside the home, but not as a shift worker.

The participants wore devices on their wrists that tracked their movement and sleep for 24 hours a day for a week. They also filled out questionnaires about their diet and health habits. Blood samples were collected to measure various health-related biomarkers, such as cholesterol and blood glucose levels.

The data revealed that about 85 percent of the participants went to sleep later and woke up later on their “free” days than on their workdays. The other 15 percent did the opposite: They got up earlier on their non-working days.

A further crunching of the data revealed that the participants with the greatest differences between their working- and non-working-day sleep schedules tended to have poorer cholesterol profiles, higher fasting insulin levels, and more resistance to insulin than the participants with less social jetlag. They also had larger waist circumferences and higher body mass indexes.

Those factors are all associated with an increased risk of type 2 diabetes and heart disease. 

The findings held even after the researchers adjusted for health behaviors, such as physical activity, calorie intake and alcohol consumption, and for how long people slept.

Limitations and implications

This study does not prove that having mismatched sleep schedules on working and non-working days contributes to diabetes or heart disease. It just found an association between social jetlag and markers for those illnesses. Other factors — ones not identified in this study and having nothing to do with social jetlag — may also explain the results.

Furthermore, the study’s findings do not mean that sleeping in on the weekends is bad for you.

What it does suggest, however, is that societal imposed work schedules that are not in sync with our natural, circadian rhythms may be harmful to our health.

“If future studies replicate what we found here, then we may need to consider as a society how modern work and social obligations are affecting our sleep and health,” said Patricia Wong, a graduate student at the University of Pittsburgh and the study’s lead author, in a released statement. “There could be benefits to clinical interventions focused on circadian disturbances, workplace education to help employees and their families make informed decisions about structuring their schedules, and policies to encourage employers to consider these issues.”

You’ll can read the study in full at the Journal of Clinical Endocrinology & Metabolism website.

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Pedestrian wheelchair users are at increased risk of dying in road collisions, study finds

Pedestrians who use wheelchairs are a third more likely to be struck and killed by a car or other motor vehicle than other pedestrians, according to a study published Thursday in the journal BMJ Open.

The findings demonstrate yet another reason why we need to improve our pedestrian infrastructure so that our streets are safer for everyone, including people using motorized or standard wheelchairs.

“When there is poor pedestrian infrastructure or it's poorly adapted to people with mobility impairments, people who use wheelchairs often are forced to use the streets, or are otherwise exposed to greater risk,” said John Kraemer, the study’s lead author and a public health epidemiologist at Georgetown University, in a released statement.

Each year in the U.S., about 5,000 pedestrians — in and out of wheelchairs — are killed and another 76,000 are injured in crashes on public roads, according to government statistics.

Men at greatest risk

For the study, Kraemer and his co-author, Dr. Connor Benton, a resident at MedStar Georgetown University Hospital, used data from two sources: the National Highway Traffic Safety Administration's Fatality Analysis Reporting System (FARS) and news stories about fatal car crashes published on the LexisNexis U.S. newspaper database.

From this data, they estimated that 528 pedestrians using wheelchairs were killed in traffic collisions between 2006 and 2012 — a rate that was 36 percent higher than that for other pedestrians.

The risk was especially high for men who use wheelchairs, especially those between the ages of 50 and 64. They were 75 percent more likely to be killed in a pedestrian-car accident their other men their age.

A failure to yield

Digging deeper into the data, Kraemer and Benton found that more than half of the fatal pedestrian accidents involving people using wheelchairs occurred on arterial roadways — busy streets that serve as “collector roads” to freeways. They also found that about half of the accidents were at intersections.

Of those intersection accidents, almost 40 percent occurred where there were no crosswalks, pedestrian signals or other infrastructure to help people on foot — or in wheelchairs — cross the road.

Most of the accidents — 90 percent — took place during fair weather, and almost half took place during daylight. According to the police reports, 11 of the pedestrians and 9 percent of the drivers had been using alcohol or drugs.

In three-quarters of the accidents, men were behind the wheel of the car or other motor vehicle. The most common reason for the accident (cited by the police in 36 percent of the cases) was failure of the vehicle driver to yield the right of way. In about 15 percent of the accidents, the police said the leading contributing factor was the wheelchair not being visible to the driver.

In 76 percent of the accidents, the driver had taken no braking, steering or other manuevers to avoid hitting the pedestrian.

Making pedestrian safety a priority

“That crashes frequently were attributed by police to a driver’s failure to yield right-of-way underscores the challenges faced by pedestrians who use wheelchairs as they seek to safely [use] existing pedestrian infrastructure,” write Kraemer and Benton.

“Improving pedestrian safety for people using wheelchairs should be a policy priority,” they add. “Some improvements are general to road safety: reducing distracted driving and pedestrian activity, improving safe crossing behaviour, reducing incapacitated driving, and improving pedestrian infrastructure — all of which appear to have played a role in a significant number of fatal crashes identified in this study. Others are specific to pedestrian risks faced by wheelchair users: low conspicuity of the wheelchair and pedestrian infrastructure that is particularly ill-suited to pedestrians who use wheelchairs.”

Under the Americans with Disability Act, roads are required to be wheelchair accessible by having curb cuts and ramps. But, as Kraemer told The Atlantic CityLab reporter Linda Poon, traffic engineers and other urban planners don’t focus enough on people with disabilities.

“If you really want to have zero pedestrian death we have to not only think about pedestrians as whatever our archetype is,” he said, “but also people who use wheelchairs, who are blind or deaf, who otherwise might be at greater risk because of the environment.”

You can read Kraemer’s study in full on the BMJ Open website.

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New Nerve Drugs May Finally Prevent Migraine Headaches

The cause of migraine headaches has eluded scientists for centuries. Now a theory blaming one nerve has led to drugs that prevent attacks -- Read more on

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Iodine-containing Contrast Agents for Medical Imaging: Drug Safety Communication – Rare Cases of Underactive Thyroid in Infants

Audience: Radiology, Endocrinology, Patient ISSUE: FDA is advising that rare cases of underactive thyroid have been reported in infants following the use of contrast media containing iodine, also called “contrast dye,” for X-rays and other...

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Antibiotics in Animal Feed May Endanger Kids, Doctors Warn

The widespread practice of giving antibiotics to healthy livestock to promote growth and prevent disease is making the drugs ineffective, the American Academy of Pediatrics says -- Read more on

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U.S. Deaths Drop for Leading Causes

Fatalities from causes like heart disease, cancer and stroke dropped 43 percent between 1969 and 2013 -- Read more on

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An Overreaction to Food Allergies

Many children are wrongly diagnosed with food allergies because of inaccurate tests -- Read more on

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Plavix (clopidogrel): Drug Safety Communication – Long-term Treatment Does Not Change Risk of Death

Audience: Cardiology, Hematology, Surgery ISSUE: An FDA review has determined that long-term use of the blood-thinning drug Plavix (clopidogrel) does not increase or decrease overall risk of death in patients with, or at risk for, heart disease. FDA...

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