Respiratory function of very prematurely born infants at follow up: influence of sex.
OBJECTIVE
To test the hypothesis that male compared with female prematurely born infants would have worse lung function at follow up.


METHODS
Prospective follow up study.


METHODS
Tertiary neonatal intensive care units


METHODS
Seventy six infants, mean (SD) gestational age 26.4 (1.5) weeks, from the United Kingdom oscillation study.


METHODS
Lung function measurements at a corrected age of 1 year.


METHODS
Airways resistance (Raw) and functional residual capacity (FRC(pleth)) measured by whole body plethysmography, specific conductance (sGaw) calculated from Raw and FRC(pleth), and FRC measured by a helium gas dilution technique (FRC(He)).


RESULTS
The 42 male infants differed significantly from the 34 female infants in having a lower birth weight for gestation, requiring more days of ventilation, and a greater proportion being oxygen dependent at 36 weeks postmenstrual age and discharge. Furthermore, mean Raw and FRC(pleth) were significantly higher and mean sGaw significantly lower. After adjustment for birth and current size differences, the sex differences in FRC(pleth) and sGaw were 15% and 26% respectively and remained significant.


CONCLUSIONS
Lung function at follow up of prematurely born infants is influenced by sex.
Thomas
M R
MR
Department of Child Health, 4th Floor Golden Jubilee Wing, King's College Hospital, London SE5 9RS, UK.
Marston
L
L
Rafferty
G F
GF
Calvert
S
S
Marlow
N
N
Peacock
J L
JL
Greenough
A
A
D000403:Airway Resistance / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D005652:Functional Residual Capacity; D006801:Humans; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology; D008297:Male; D011446:Prospective Studies; D012044:Regression Analysis; D012120:Respiration Disorders / Q000503:physiopathology*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012727:Sex Characteristics