Differences in immunoreactive trypsin values between type of feeding and ethnicity in neonatal cystic fibrosis screening: a cross-sectional study.
BACKGROUND
We studied the differences in immunoreactive trypsin (IRT) in neonatal screening for cystic fibrosis (CF) associated individually with the age of the newborn, ethnicity and environmental temperature. In this study, we determine the overall influence of environmental temperature at birth, gender, feeding, gestational age, maternal age and ethnic origin on an abnormal IRT result.


METHODS
Cross-sectional observational study. A sample was selected of newborns from Alicante (Spain) who underwent neonatal CF screening in 2012-2013. Primary variable: abnormal IRT levels (≥65 ng/ml). Secondary variables: gender, maternal origin, maternal age (years) (<20, 20-40, >40), gestational age (weeks) (<32, 32-37, >37), type of feeding (natural, formula, mixed and special nutrition), >20 days from birth to blood collection, and average temperature during the month of birth (in°C). Using a multivariate logistic regression model the adjusted odds ratios (ORs) were estimated to analyze the association between atypical IRT levels and the study variables. The α error was 5% and confidence intervals (CI) were calculated for the most relevant parameters.


RESULTS
Of a total of 13,310 samples, 199 were abnormal (1.34%). Significant associated factors: feeding method (natural → OR = 1; mixed → OR = 0.53, 95% CI: 0.31-0.89; formula → OR = 0.72, 95% CI: 0.48-1.07; special → OR = 21.88, 95% CI: 6.92-69.14; p < 0.001).


CONCLUSIONS
Newborns receiving special nutrition have a 20-fold higher risk for abnormal IRT levels, and screening is advisable once normalized feeding is initiated. It is advisable to consider ethnic variability. Seasonality was not important.
Pharmacology, Paediatrics and Organic Chemistry Department, Miguel Hernández University, San Juan de Alicante, Spain. ernestocort@gmail.com.
Ernesto
E
Cortés
Clinical Analysis Department, Alicante General University Hospital, Alicante, Spain. amroldanc@hotmail.com.
Ana María
AM
Roldán
Clinical Medicine Department, Miguel Hernández University, Carretera de Valencia-Alicante S/N, 03550, San Juan de Alicante, Spain. antonio.pb23@gmail.com.
Antonio
A
Palazón-Bru
Nursing Department, University of Alicante, San Vicente del Raspeig, Spain. mercedes.rizo@ua.es.
María Mercedes
MM
Rizo-Baeza
Clinical Analysis Department, Alicante General University Hospital, Alicante, Spain. manero_her@gva.es.
Herminia
H
Manero
Clinical Medicine Department, Miguel Hernández University, Carretera de Valencia-Alicante S/N, 03550, San Juan de Alicante, Spain. vte.gil@gmail.com.
Vicente Francisco
VF
Gil-Guillén
D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology*; D005006:Ethnicity; D005260:Female; D005865:Gestational Age; D006801:Humans; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening / Q000379:methods*; D012307:Risk Factors; D014357:Trypsin / Q000097:blood*
D014357:Trypsin