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Vol. LXVI, No. 7
March 28, 2014
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Digest

Prevalence of Allergies the Same, Regardless Of Where You Live

Scientists from NIH report that allergy prevalence is the same across different regions of the United States, except in children 5 years and younger.

Scientists from NIH report that allergy prevalence is the same across different regions of the United States, except in children 5 years and younger.

In the largest, most comprehensive, nationwide study to examine the prevalence of allergies from early childhood to old age, scientists from NIH report that allergy prevalence is the same across different regions of the United States, except in children 5 years and younger.

“Before this study, if you would have asked 10 allergy specialists if allergy prevalence varied depending on where people live, all 10 of them would have said yes, because allergen exposures tend to be more common in certain regions of the U.S.,” said Dr. Darryl Zeldin, NIEHS scientific director. “This study suggests that people prone to developing allergies are going to develop an allergy to whatever is in their environment. It’s what people become allergic to that differs.”

The research appeared online in the Journal of Allergy and Clinical Immunology.

Although the study found that the overall prevalence of allergies did not differ between regions, researchers discovered that one group of participants did exhibit a regional response to allergens. Among children ages 1-5, those from the southern U.S. displayed a higher prevalence of allergies than their peers living in other U.S. regions.

“The higher allergy prevalence among the youngest children in southern states seemed to be attributable to dust mites and cockroaches,” said Dr. Paivi Salo, an epidemiologist in Zeldin’s research group and lead author on the paper.

Researchers Find Reason Why Many Vein Grafts Fail

NIH researchers have identified a biological pathway that contributes to the high rate of vein graft failure following bypass surgery. Using mouse models of bypass surgery, they showed that excess signaling via the transforming growth factor beta (TGF-beta) family causes the inner walls of the vein to become too thick, slowing down or sometimes even blocking the blood flow that the graft was intended to restore. Inhibition of the TGF-B signaling pathway reduced overgrowth in the grafted veins.

The team, led by Dr. Manfred Boehm, chief of the Laboratory of Cardiovascular Regenerative Medicine, NHLBI, identified similar properties in samples of clogged human vein grafts, suggesting that select drugs might be used in reducing vein graft failure in humans.

This study was published Mar. 12 in Science Translational Medicine.

Bypass surgery to restore blood flow hindered by clogged arteries is a common procedure in the United States. The great saphenous vein, which is the large vein running up the length of the leg, often is used as the bypass conduit due to its size and the ease of removing a small segment. After grafting, the implanted vein remodels to become more arterial, as veins have thinner walls than arteries and can handle less blood pressure. However, the remodeling can go awry and the vein can become too thick, resulting in a recurrence of clogged blood flow. About 40 percent of vein grafts experience such a failure within 18 months of the operation.

High Plasticizer Levels in Males Linked to Delayed Pregnancy for Female Partners

Women whose male partners have high concentrations of three common forms of phthalates—chemicals found in a wide range of consumer products—take longer to become pregnant than women in couples in which the male does not have high concentrations of the chemicals, according to researchers at NIH and other institutions.

The researchers assessed the concentrations of phthalates and bisphenol A (BPA) in couples trying to achieve pregnancy. Phthalates, sometimes known as plasticizers, are used in the manufacture of plastics, to make them more flexible. BPA is also used in plastics, including in some food and drink packaging.

According to the Centers for Disease Control and Prevention, phthalates are used in hundreds of products such as fragrances, shampoos, nail polish, plastic film and sheets. Pregnancy took the most time to achieve in couples in which the males had high concentrations of monomethyl phthalate, mono-butyl phthalate and monobenzyl phthalate.

Because the researchers examined only the time it took to achieve pregnancy, the study could not determine precisely how the compounds might affect fertility. Future studies, the authors wrote, would be needed to determine if the compounds affected particular aspects of reproductive health, such as hormone levels. The study was published online in the journal Fertility and Sterility.


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