The results of a study of twins by the Mailman School of Public Health at Columbia University suggest that an association between asthma and posttraumatic stress disorder (PTSD) is not easily explained by common genetic factors.
The researchers looked at 3065 pairs of male twins who were Vietnam veterans. The brothers had lived together during childhood, and both served active military duty. The researchers found that among all twins, those who experienced the most PTSD symptoms were also 2.3 times more likely to have asthma, compared with those who experienced fewer PTSD symptoms. The findings suggest that a patient with asthma who experiences a traumatic event could benefit from professional help to avoid developing the disorder.
This new research helps bolster previous studies that support a link between asthma and other anxiety disorders, including depression. The findings were reported in the November 15, 2007, issue of the American Journal of Respiratory and Critical Care Medicine.
Researchers have long debated whether people who develop asthma have a genetic propensity to develop allergies, and results of a study conducted by the National Institutes of Health show that this may be the case. They found that 56.3% of the asthma cases studied were attributed to preexisting allergies, or atopy, a condition that results from gene?environment interactions and can be measured by a positive skin test for allergens. The study was published in the September 2007 online version of the Journal of Allergy and Clinical Immunology.
The researchers examined data from skin tests for 10 allergens that involved about 10,500 participants. They found that a positive skin test reaction to cat allergens accounted for 29.3% of the asthma cases, followed by the fungus Alternaria at 21.1% and white oak at 20.9%. Although all of the 10 allergens were associated with asthma, only these 3 were "independently and positively" associated, said the researchers.
Children who eat more fish and vegetables might have a chance of avoiding allergies or asthma, according to a Greek study. Researchers from the University of Crete, Heraklion, Greece followed 460 Spanish children from birth to age 6 and found that those who ate more fish were the least likely to develop allergies, compared with their peers who ate less fish.
They also found fewer instances of asthma among children who consumed the most ?fruity? vegetables, such as eggplant, tomatoes, green beans, and zucchini (fruits and other types of vegetables had no similar effect). Parents of the participating children answered questions on a variety of factors that affected a child?s risk of developing allergies, such as mother?s diet during pregnancy, breast-feeding, exposure to secondhand smoke in the home, and family history of allergies and asthma. After taking these and other factors into account, the researchers found that diet was still strongly related to a child?s asthma or allergy risk.
The researchers encouraged parents, especially those whose families carry one or more risk factors for allergy/asthma, to include these foods in their children?s diets regularly. The findings were reported in the September 2007 issue of the journal Pediatric Allergy and Immunology.
Although it is true that breast-feeding is best for babies, helping them stave off diarrhea, ear infections, and incidents of wheezing, the breathing benefits may be lacking in children whose mothers have asthma.
Researchers from the University of Wisconsin-Madison and the Arizona Respiratory Center at the University of Arizona in Tucson noted that "longer breast-feeding in infancy is associated with improved lung function in later childhood, with minimal effects on airflow in children of nonasthmatic mothers."When the mother has asthma, however, breastfeeding "demonstrates no improved lung growth and significant decrease in airflows later in life."
Investigators looked at data from the Children's Respiratory Study in Tucson, on 1246 infants enrolled at birth and monitored through adolescence. Of these, 679 participants who had performed lung function testing between the ages of 11 and 16 and had also disclosed complete information on infant feeding practices were analyzed. Researchers found that those who were breast-fed by mothers with asthma for 4 months or longer "had a significant reduction in airflows" as adolescents.
They speculated that the breast milk of nonasthmatic mothers may contain certain elements that promote lung development that asthmatic mothers may lack. The findings were reported in the November 1, 2007, issue of the American Journal of Respiratory and Critical Care Medicine.
F A S T F A C T : One in 3 asthma patients uses a rescue inhaler at least daily, and 73% use one at least once a month.
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