In a new study, scientists showed that quite unlike previous scientific opinion, progressive lung damage in CF patients could begin as early as infancy even though lung function shortly after diagnosis is normal.
"We might be able to stop some of the lung function reduction we're identifying in the first months of life. We don't know what's going to work, but we have to target those patients in the first six months of life if we're going to be effective," said Dr. Sarath Ranganathan, Ph.D., consultant respiratory physician at the Royal Children's Hospital in Melbourne, and lead author of the paper,
In the study conducted in Australia, 68 infants with CF were compared to 49 infants without the disease. The children were between six weeks and 30 months of age. Forced expiratory volume (FEV) measurements were obtained for the children at baseline, and 16 of the children with CF were measured again one year later.
The researchers found that FEV was equivalent for all children both with and without CF at baseline. However, by the time the kids reached six months of age, the mean FEV score was significantly lower in infants with CF compared to controls-and the deficit increased with each month of age.
"This finding indicates that lung function declines sooner than previously thought," said Ranganathan.
Also, it was found that diminished lung function occurred even in the absence of clinical symptoms and irrespective of CF genotype. But, notably, infants measured soon after birth and within the first six months of life had normal lung function.
The finding validates the early-screening approach taken in Australia and strongly suggests that other nations should adopt similar approaches.
"Ninety percent of those with CF can't absorb the fat in their diet, and people with this condition who are better nourished live longer. [Those patients] should take manufactured pancreatic enzymes with every meal that contains fat, so they can have a good high-fat diet with lots of calories. Although the patients in our study were well-nourished, they still had diminished lung function. However, we can't be certain whether or not fat malabsorption that occurs prior to starting enzymes at diagnosis contributes to diminished lung function later on in early childhood," said Dr. Ranganathan.
He added that if better tests for lung function in newborns could be developed, they could determine that lung function is not in fact normal during the first six months.
"Our paper really indicated that lung function is diminished after the first six months, but appears to be normal in the first six, which is good news and bad news. It's bad news because even with the best current treatment we don't seem able to prevent diminished lung function occurring in later infancy. The good news is that if we can diagnose infants with this condition early by newborn screening, we have shown for the first time that there appears to be a window of opportunity in the first six months of life to intervene to prevent diminished lung function," he said.
The study appeared in the second issue for December of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.