Relationship between nutritional status and lung function in cystic fibrosis: cross sectional and longitudinal analyses from the German CF quality assurance (CFQA) project.
BACKGROUND
The German cystic fibrosis (CF) quality assurance (CFQA) project is a patient registry for CF which was founded in 1995. Relevant clinical and laboratory data, respiratory function test results, complications, and CF treatments are entered into the database once a year for each patient. Using the database, a study was undertaken to elucidate the relationship between nutrition and lung function in a large patient cohort by cross sectional and longitudinal analysis.


METHODS
A cohort of 3298 patients above 2 years of age was analysed. Patients were grouped according to the presence or absence of malnutrition (wasting and/or stunting). Cross sectional and longitudinal analyses over 2 and 3 years including mixed model analyses were performed.


RESULTS
The prevalence of abnormal weight for height (<90% predicted) increased with age from 19% in children aged <6 years to 38% in adults with CF. Patients with malnutrition had significantly lower mean values of vital capacity, arterial oxygen tension (PO(2)), and forced expiratory volume in 1 second (FEV(1)) and higher serum IgG (p<0.05). Pseudomonas aeruginosa infection was also associated with decreased pulmonary function. Malnourished adolescents aged 12-18 years experienced a serious decline in FEV(1) of about 20% predicted, whereas mean FEV(1) values remained stable at above 80% predicted in adolescents of normal weight. Longitudinal follow up showed that malnourished patients of all ages and those with P aeruginosa infection had significantly worse lung function than their normally nourished counterparts and a greater yearly loss of FEV(1) % predicted. During 1 year of observation adolescents who experienced a >5% predicted decrease in weight for height had a concomitant mean loss of FEV(1) of 16.5% predicted during that year, whereas patients who gained relative weight had a parallel increase in FEV(1) of 2.1% predicted.


CONCLUSIONS
These data emphasise the close relationship between nutrition, lung function, and clinical course in CF. Normal body weight and absence of P aeruginosa infection was associated with better preservation of lung function.
Steinkamp
G
G
Clinical Research, Hannover, and CF Centre Hamburg-Altona, Germany. gratiana.steinkamp@t-online.de
Wiedemann
B
B
D000293:Adolescent; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000150:complications / Q000503:physiopathology*; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D009748:Nutrition Disorders / Q000150:complications / Q000503:physiopathology*; D009752:Nutritional Status; D011552:Pseudomonas Infections / Q000150:complications / Q000503:physiopathology; D011550:Pseudomonas aeruginosa; D014797:Vital Capacity / Q000502:physiology