A recent study found improvements in lung function and body mass index (BMI) among children and young adults with cystic fibrosis (CF) both in the United States and Canada from 1990 to 2013, though the American patients improved faster than those in Canada.
The study, “Comparison of Nutrition and Lung Function Outcomes in Patients with Cystic Fibrosis Living in Canada and the United States,” appeared in the American Journal of Respiratory and Critical Care Medicine.
The analysis — which included data from 5,149 patients in the Canadian Cystic Fibrosis Registry and 37,772 patients in the U.S. Cystic Fibrosis Foundation Registry — compared changes in lung function and BMI among CF patients in both countries from 1990 to 2013.
It found that, while lung function improved in both countries, Americans with CF born after 1990 are nutritionally healthier than those north of the border, and that certain age groups showed faster improvement in the United States.
Specifically, the lung function of U.S. children in the 6-18 age bracket surpassed that of Canadian children in 2002, while young Americans aged 19-40 surpassed similarly aged Canadian CF patients in lung function by 2006.
Yet lung function in U.S. patients over 40 was worse than that of similarly aged Canadians for the entire study period.
Lung function and nutritional status are two key factors known to influence survival in CF patients. Maintaining a healthy weight is a key predictor of outcomes in CF, given that improper nutrition is a serious problem with this disease.
The study assessed lung function through forced expiratory volume (FEV) measures — the amount of air an individual can exhale during a forced breath — and FEV1, the air exhaled during the first second after a deep breath.
The median FEV1 predicted for U.S. children aged 6-18 increased by 2.9 percent over a five-year period in comparison to Canadian children, who had a median increase of 2.1 percent.
The team suggested that the faster U.S. rate of improvement in nutrition and lung function could be thanks to newborn screening or other initiatives, as well as access to medical care now facilitated by the 1997 Medicaid Children’s Health Insurance Program (CHIP).
“The reasons for the observed improvements, and catch-up in the U.S., are likely multifactorial, and include the introduction of high-fat/high-calorie diets, introduction of newborn screening, and/or improved access to care for CF children in the U.S.,” researchers wrote.
“The findings from this study are encouraging in that they support positive trends in the health of people with CF in both Canada and the U.S.,” Bruce Marshall, lead study investigator for the Cystic Fibrosis Foundation and senior vice president of clinical affairs at CFF, said in a press release. “As a community, we can all take pride in these improvements while continuing to learn as much as we can to slow down the progression of this disease and improve the quality of life for all those living with it.”