HEALTH

New study suggests blood pressure should be measured in both arms

BY Michael Johnsen

PHILADELPHIA — New research published in the March issue of the American Journal of Medicine suggests that there is an association between a difference in interarm systolic blood pressure and a significant increased risk for future cardiovascular events, leading researchers to recommend expanded clinical use of interarm blood-pressure measurement.

While blood pressure is a widely used medical metric, most measurements are taken only using one arm. Measuring interarm blood pressure involves taking two readings, one for each arm. Increased interarm systolic blood pressure differences are defined as 10 mmHg or more, and while a link between interarm blood pressure and cardiovascular risk was suspected, little data existed to support the hypothesis until now. 

This new study examined 3,390 participants ages 40 years and older from the Framingham Heart Study. All subjects were free of cardiovascular disease at baseline, but investigators found that participants with higher interarm systolic blood-pressure differences were at a much higher risk for future cardiovascular events than those with less than a 10 mmHg difference between arms.

"In this large prospective, in a community-based cohort of middle-age men and women free of cardiovascular disease, an increased interarm systolic blood pressure difference was found to be present in nearly 10% of individuals and is associated with increased levels of traditional cardiovascular risk factors," explained lead investigator Ido Weinberg of the Institute for Heart Vascular and Stroke Care at Massachusetts General Hospital in Boston. "Furthermore, an increased interarm systolic blood pressure difference is associated with an increased risk for incident cardiovascular events, independent of traditional cardiovascular risk factors."

Researchers also found that participants with elevated interarm blood pressure difference were older, had a greater prevalence of diabetes mellitus, higher systolic blood pressure and a higher total cholesterol level.

According to these findings, investigators suggest practitioners should consider including blood-pressure readings in both arms in order to get the most accurate readings possible and detect any differences in interarm blood pressure. "Even modest differences in clinically measured systolic blood pressures in the upper extremities reflect an increase in cardiovascular risk," Weinberg said. "This study supports the potential value of identifying the interarm systolic blood pressure difference as a simple clinical indicator of increased cardiovascular risk."

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Researchers explore viability of self-administered flu vaccine patch

BY Michael Johnsen

ATLANTA — The annual ritual of visiting a doctor’s office or health clinic to receive a flu shot may soon be outdated, thanks to the findings of a new study published in the journal Vaccine.

The research, which involved nearly 100 people recruited in the metropolitan Atlanta area, found that test subjects could successfully apply a prototype vaccine patch to themselves. That suggests the self-administration of vaccines with microneedle patches may one day be feasible, potentially reducing administration costs and relieving an annual burden on healthcare professionals.

The study also suggested that the use of vaccine patches might increase the rate at which the population is vaccinated against influenza. After comparing simulated vaccine administration using a patch and by conventional injection, the percentage of test subjects who said they’d be vaccinated grew from 46% to 65%.

"Our dream is that each year there would be flu vaccine patches available in stores or sent by mail for people to self-administer," stated Mark Prausnitz, a Regent’s professor in the School of Chemical and Biomolecular Engineering at the Georgia Institute of Technology. "People could take them home and apply them to the whole family. We want to get more people vaccinated, and we want to relieve healthcare professionals from the burden of giving these millions of vaccinations."

In addition to Georgia Tech researchers, the project also included scientists from Emory University and the Centers for Disease Control and Prevention. Research into the use of microneedle patches for influenza vaccination has been supported by the National Institutes of Health.

The study is believed to be the first published report of a head-to-head comparison between microneedle patches and traditional intramuscular injection for the administration of vaccines in human subjects. The patches consisted of arrays of 50 microscopic needles about as tall as the thickness of a few hairs. When used for vaccination, the patches would be pressed painlessly onto a person’s forearm to carry vaccine into the outer layers of skin, where they would prompt an immune reaction from the body.

The 91 study subjects, who had no previous experience with microneedle patches, were given brief instructions on applying the patches to themselves. Each volunteer applied three patches, had a fourth patch applied by a member of the research team, and received an injection of saline with a conventional hypodermic needle. Neither the patches nor the hypodermic needle actually carried a vaccine, and the study did not assess the efficacy of using microneedle patches for vaccinations in humans.

The researchers evaluated how well the volunteers were able to self-administer the microneedle patches. After the subjects pressed the patches into their skin, the researchers applied a dye to highlight the tiny holes made by the microneedles. By photographing the administration sites and counting the number of holes, they were able to assess the accuracy of the application.

"We found that everyone was capable of administering a microneedle patch appropriately, though not everyone did on the first try," Prausnitz said.

Some of the subjects used an applicator that made a clicking sound when sufficient force was applied to the patch. Use of that feedback device improved the ability of subjects to correctly apply patches and virtually eliminated administration mistakes.

During the study, the volunteers were asked if they planned to receive a flu vaccination in the next year and if their intent to be vaccinated would change if it could be done with the patch. The percentage saying they’d be vaccinated jumped from 46% to 65% when the patch was an option.

"If this holds for the population as a whole, that would have a tremendous impact on preventing disease and the cost associated with both influenza and the vaccination process," stated Paula Frew, an assistant professor in the Emory University School of Medicine and a co-author of the study.

"In addition to the preference for the vaccine patch, we found that a large majority of the people willing to be vaccinated would choose to self-administer the vaccine," said James Norman, the study’s first author, who was a Georgia Tech graduate student when the research was conducted.

Study participants were asked to assess the pain associated with administering the patch and receiving the intramuscular injection. On a scale of 1 to 100, they rated the patches 1.5 on average, while the injection was rated 15.

If all goes well, the vaccine patch could be available within five years. Prausnitz expects it to be administered first by healthcare professionals before being made available for self-administration.

 

 

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Researchers discover how low vitamin D levels are linked to Autism Spectrum Disorder

BY Michael Johnsen

OAKLAND, Calif. — A study released Wednesday by Rhonda Patrick and Bruce Ames of Children’s Hospital Oakland Research Institute demonstrated the impact that vitamin D may have on social behavior associated with Autism Spectrum Disorder. 

Patrick and Ames show that serotonin, oxytocin and vasopressin, three brain hormones that affect social behavior, are all activated by vitamin D hormone. Autism, which is characterized by abnormal social behavior, has previously been linked to low levels of serotonin in the brain and to low vitamin D levels, but no mechanism has linked the two until now. 

In this study, Patrick and Ames show that vitamin D hormone activates the gene that makes the enzyme tryptophan hydroxylase 2 (TPH2), which converts the essential amino acid tryptophan, to serotonin in the brain. This suggests that adequate levels of vitamin D may be required to produce serotonin in the brain where it shapes the structure and wiring of the brain, acts as a neurotransmitter and affects social behavior. They also found evidence that the gene that makes the enzyme tryptophan hydroxylase 1 (TPH1) is inhibited by vitamin D hormone, which subsequently halts the production of serotonin in the gut and other tissues, where when found in excess, it promotes inflammation.

This mechanism explains many of the known, but previously not understood facts about autism including: 1) the "serotonin anomaly" low levels of serotonin in the brain and high levels in the blood of autistic children; 2) the preponderance of male over female autistic children: estrogen, a similar steroid hormone, also can boost the brain levels of serotonin in girls; 3) the presence of autoimmune antibodies to the fetal brain in the mothers of autistic children: vitamin D regulates the production of regulatory T-cells via repression of TPH1. The Patrick/Ames mechanism is relevant to the prevention of autism, and likely its treatment, the researchers concluded.

The study suggests dietary intervention with vitamin D, tryptophan and omega-3 fatty acids would boost brain serotonin concentrations and help prevent and possibly ameliorate some of the symptoms associated with ASD without side effects. There is little vitamin D present in food, and fortification is still inadequate as is the amount in most multivitamin and prenatal supplements. In addition, vitamin D levels should be routinely measured in everyone and should become a standard procedure in prenatal care.

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