Does Childhood Asthma Lead to COPD?

Early childhood asthma, particularly when severe, seems to impart risk of COPD - an adult condition associated with abnormal lung function that declines over time faster than the general population.  Can controlling asthma early prevent this? Dr. Susarla

The association between childhood asthma and adult chronic obstructive pulmonary disease.

INTRODUCTION:

There is epidemiological evidence to suggest that events in childhood influence lung growth and constitute a significant risk for adult COPD. The aim of the study is to evaluate for an association between childhood asthma and adult COPD.

METHODS:

This longitudinal, prospective study of 6-7-year-old children with asthma has been regularly reviewed every 7 years to the current analysis at 50 years of age. Participants completed respiratory questionnaires and lung function spirometry with postbronchodilator response. At the age of 50, subjects were classified to the following subgroups: non-asthmatics, asthma remission, current asthma and COPD which was defined by FEV₁ to FVC ratio postbronchodilator of less than 0.7.

RESULTS:

Of the remaining survivors, 346 participated in the current study (participation rate of 76%) of whom 197 completed both questionnaire and lung function testing. As compared with children without symptoms of wheeze to the age of 7, (non-asthmatics) children with severe asthma had an adjusted 32 times higher risk for developing COPD (95% CI 3.4 to 269). In this cohort, 43% of the COPD group had never smoked. There was no evidence of a difference in the rate of decline in FEV₁ (mL/year, 95th CI) between the COPD group (17, 10 to 23) and the other groups: non-asthmatics (16, 12 to 21), asthma remission (20, 16 to 24) and current asthma (19, 13 to 25).

CONCLUSIONS:

Children with severe asthma are at increased risk of developing COPD.

Article linked here.

Preterm Birth May Raise Child's Asthma Risk, Study Suggests

Premie infants seem to have a higher risk for early childhood wheezing, which often follows a pattern consistent with asthma. Dr. Susarla

THURSDAY, March 13, 2014 (HealthDay News) -- A new study may add asthma to the list of downsides of being born too early.

Children who were born prematurely appear to be at higher risk for asthma and wheezing disorders, according to a new review.

Researchers led by Dr. Aziz Sheikh, of Brigham and Women's Hospital in Boston, looked at 30 studies focused on links between preterm birth -- defined as less than 37 weeks' gestation -- and asthma or wheezing disorders among more than 1.5 million children.

Their analysis found that preterm babies were 70 percent more likely than full-term infants to develop asthma or wheezing disorders later in childhood. Overall, close to 14 percent of "preemie" babies went on to develop asthma during childhood, compared to 8.3 percent of babies born at term.

The risk was even higher for very preterm babies, defined as children born at less than 32 weeks' gestation. These infants were about three times more likely than full-term babies to develop asthma or wheezing disorders later on.

"Worldwide, more than 11 percent of babies are born preterm," Sheikh said in a hospital news release.

"As asthma is a chronic condition, our findings underscore the need to improve our understanding of the mechanisms underlying the association between preterm birth and asthma or wheezing disorders in order to develop preventive and therapeutic interventions," he said.

Although the study found an association between premature birth and later asthma, it could not prove cause and effect. The findings were published in a recent issue of the journal PLoS Medicine.

Read article here.

Adding to the state of asthma research in children, there appear to be specific genes that confer risk of wheezing in children possibly portending risk of asthma as well.  Dr. Susarla

Genetic Variants and Wheezing Put Kids At Risk For Asthma

Almost every toddler will sniffle through a cold by the time they are three, but if they wheeze while they’re sick, they may be at higher risk of developing asthma.

Previous research found that wheezing-related illnesses can increase a child’s risk for developing asthma, and other studies connected certain genetic factors to this heightened tendency to wheeze. In a new study published in the New England Journal of Medicine, researchers connected the two and found that 90% of three-year-olds with a combination of specific genes and a particular wheezing illness were diagnosed with asthma by the age of 6.

The scientists focused on a region of chromosome 17, known as 17q21 that has been associated with an elevated risk of asthma early in life. Two genes in the region likely increase this risk — ORMDL3 and GSDMB. Variants of these genes, which are relatively common, seemed to confer higher risk of wheezing when children were infected with the rhinovirus, which is responsible for the common cold. About half of the infants in the study had one copy of the variant, while a quarter had both copies, which significantly increased their likelihood of wheezing and developing asthma.

The researchers included children from two separate study groups, all of whom came from families with a history of allergies or asthma. The first group included 200 children toddlers with at least one, and possibly two parents who had allergies or asthma while the second group consisted of Danish toddlers whose mothers were diagnosed with asthma. Among children without the high-risk genetic variants for asthma, 40% who wheezed when they caught a cold before age three developed asthma by age six, compared to 60% who had one copy of the variant and wheezed, and 90% of those who had two copies and also wheezed.

“We found that the interaction between this specific wheezing illness and a gene or genes on a region of chromosome 17 determines childhood asthma risk. The combination of genetic predisposition and the child’s response to this infection has a huge effect,” said study author Carole Ober, a Blum-Riese Professor of Human Genetics at the University of Chicago in a statement.

Overall, the children with the genetic and wheezing illness combination were almost four times as likely to develop asthma compared to kids who did not have the genetic variation or did not wheeze, suggesting that wheezing might be a relatively easy marker for identifying toddlers who might be at highest risk of developing asthma later.

The biological mechanisms underlying the connection are not well understood, but to get a better idea of what’s going on, the researchers collected blood from 100 healthy adults and exposed their immune cells to human rhinovirus. Infection with the cold virus seemed to make the asthma-related genes on chromosome 17 more active, possibly leading to more wheezing.

If the results are confirmed, then doctors and parents could be more alert to early signs of wheezing, and consider testing for the presence of the genetic variants that could increase the risk of asthma. Such early intervention could help to limit exposure to asthma triggers, such as cigarette smoke, bisphenol A and other potential irritants, and hopefully reduce the severest symptoms as well.

Read article here.