In the first long-term study of pediatricians' records on 1,246 children with pneumonia in the first 3 years of life, lower lung function persisted though adulthood.
"We initially had funding from the National Institute of Health (NIH) to study these children for the first 5-7 years," explained Fernando Martinez, MD, director, Arizona Respiratory Center, University of Arizona, Tucson and one of the study authors. "The funding continued through the present so we have objective data that isn't biased by recall. We knew the asthma continued through the school years and we hoping to see some recovery but that's not the case. The curve appear to be parallel."
Children who experienced lower respiratory illnesses during the first 3 years of their life had diminished lung function as adults, and those who suffered from pneumonia as young children were at nearly twice the risk of having asthma and wheeze as adults compared with children who had no lower respiratory illnesses, according to the longitudinal study.
Martinez, Johnny Y.C. Chan, MBChB, from the Department of Pediatrics, Kwong Wah Hospital, Hospital Authority, Kowloon, Hong Kong, and Arizona Respiratory Center, University of Arizona, Tucson, and co-authors reported their findings in an article published online March 2 in Pediatrics. The research team analyzed data from the Tucson Children's Respiratory Study, which enrolled healthy infants from 1980 to 1984, shortly after the children were born.
Parents completed questionnaires when their children were 11, 13, and 16 years old; the youths then filled out the questionnaires when they were 18, 22, 24, 26, and 29 years old. In addition to answering questions about asthma and wheezing, the parents were counseled to take their young children to pediatricians if they developed symptoms of lower respiratory illnesses, opening the door to radiologically ascertained pneumonia in children not yet hospitalized. The children's lung function was confirmed by spirometry at ages 11, 16, 22, and 26 years, and cigarette smoking was self-reported at ages 16, 18, 22, 24, 26, and 29 years.
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Compared with children who did not have early lower respiratory illnesses, those who had pneumonia during the first 3 years of life had a significantly lower forced expiratory volume in 1 second (FEV1) at ages 11, 16, and 22 years. In addition, children who had pneumonia in the first 3 years of life had a significantly lower prebrochodilator FEV1 and FEV1:forced vital capacity ratio up to age 26 years. Over the same range of ages, pneumonia was associated with a nearly doubled increased risk for asthma (odds ratio [OR], 1.95; 95% confidence interval [CI], 1.11 - 3.44) and wheeze (OR, 1.94; 95% CI, 1.28 - 2.95).
"Now, we know the pneumonia is associated with asthma and possibly COPD into adulthood," confirmed Martinez.
According to Martinez, it remains unclear whether having severe respiratory ailments early in life begins a cascade that results in lingering lung injury or whether pneumonia lodges in vulnerable young lungs. The two may have "separate and complementary" roles in early pneumonia and later deficits in adults' lung function, the authors note.
"Radiologically ascertained pneumonia before age three is associated with asthma and impaired airway function that is only partially reversible with bronchodilators and that persists into adult life," Chan and colleagues concluded in the study. "Because there is considerable evidence that asthma associated with airflow limitation is a strong risk factor for subsequent chronic obstructive pulmonary disease, the prevention of early-life pneumonia and of the factors that determine low lung function in infancy may contribute significantly to decrease the public health burden of chronic obstructive pulmonary disease."
It's also possible that another factor in utero or very early in life accounts for the connection. Prematurity predisposes some children to asthma because the lungs didn't fully grow in utero. Other children may have had other viruses that damaged their lungs, noted Martinez.
"The pneumonia is only the canary in the mine to know if something went wrong in early development," commented Martinez. "From other studies, we know that children with asthma are more likely to have continued wheezing and coughing and miss more school days. The main issue that isn't elucidated is whether or not pneumonia is the cause."
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Certainly, some asthma cases can be attributed to breathing tube damage, but the chicken-egg question remains. "Breathing tube damage is important but we don't know if it occurred before the pneumonia," acknowledged Martinez. "In some of the children who had pneumonia between birth and age 3, it's the same effect as smoking cigarettes for 10-15 years."
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With the root cause of the asthma still a mystery, Martinez said the preventing pneumonia is the only step to avoid the long-term consequence of negative lung function. As far as circumventing asthma and COPD as an adult, he was adamant that not smoking is essential.
"Number one, two and three is do not smoke if you'd had pneumonia," Martinez stated. "Other papers have shown that people who've had severe infections in their first years of life are much worse if they start smoking. It's bad to smoke if you've never had pneumonia but much, much worse if you had it."
Avoiding smoky environments and workplace fumes will also help in not triggering asthma, he said.
Attaining a pulmonary function test measuring how much air can be blown out of your lungs and how quickly will determine the amount of airway obstruction for patients with asthma and show disease progression.
"Unfortunatley, many insurance companies don't reimburse for pulmonary function testing without specific reason," declared Martinez. "However, patients and practitioners should insist upon it if the patient has repeated coughing in the winter for 3 months more than 2 consecutive years or wheezing episodes with a diagnosis of asthma. Anyone who has had significant symptoms when they were young should also insist on the (pulmonary function) test."
Robin Hocevar is on staff at ADVANCE. Contact email@example.com.