Allergies

Childhood obesity may cause asthma

It is more probable that childhood obesity contributes to asthma rather than the other way round, says a study.

Childhood obesity may cause asthma

For years, doctors have known that there is a link between childhood obesity and asthma, but have found it difficult to determine which condition tends to come first, or whether one causes the other.

“The relationship between obesity and asthma in adults, which shows that being overweight and obese can precede the onset of asthma, is supported by a number of studies,” said lead author of the study Perdita Permaul from Massachusetts General Hospital in the US.

“There is not as much evidence for children, but the progression from obesity to asthma, rather than the other way around, seems probable,” Permaul added.

Citing a study that showed that rapid growth in body mass index (BMI) during the first two years of life increased the risk of asthma up to six years of age, the team shows that the onset and duration of obesity and the composition of the excess fat can affect lung function.

“Most kids who suffer from asthma also have allergies,” said Michael Foggs, president, American College of Allergy, Asthma and Immunology (ACAAI).

“These allergic responses in the lung can lead to symptoms of allergy,” Foggs added.

The study appeared in the journal Annals of Allergy, Asthma and Immunology.

Source: times of india

Exposure to Dogs May Keep Kids from Developing Allergies

Exposure to “dog dust,” or the dried flakes of skin that fall from Fido, may protect against developing allergies and asthma in later life by altering intestinal bacteria, a new study in mice suggests.

The dust appears to contain bacteria that, when present in an animal’s gut, affects the production of immune cells in the animal’s airway.

“Perhaps early life dog exposure introduces microbes into the home that somehow influence the gut microbiome, and change the immune response in the airways,” said study researcher Susan Lynch, an associate professor of medicine at the University of California, San Francisco.

Past research has shown that exposure to pets, particularly dogs, during infancy may prevent people from developing allergies, and other work has found that bacteria in the gut can affect allergies and asthma. The new study adds to the research because it links these ideas showing that the reason exposure to dog dust may prevent allergies is that the dust affects the population of gut microbes.

In the study, Lynch and her colleagues exposed mice to dust from a dog owner’s home, and then tested the mice’s immune response to cockroach allergens and ovalbumin (a component of egg whites), two substances that commonly trigger asthma attacks. They found that mice exposed to dog dust had fewer immune cells in the airway that respond to allergens, compared with mice not exposed to dog dust.

The findings, detailed online today (Dec. 16) in the journal Proceedings of the National Academy of Sciences, hint at a mechanism for how dog exposure may protect against allergies or asthma.

“It seems to be that early life exposure to dogs, and cats to a lesser extent, can protect against asthma allergens,” Lynch told LiveScience, though she stopped short of recommending exposing infants to dogs

Source: Healcon