Associations between fetal size, maternal α-tocopherol and childhood asthma

Background The origins of respiratory disease might be traced back to exposures during fetal life. The aim of the present study was to explore whether there was a relationship between fetal size and respiratory outcomes at 5 years of age in the context of fetal exposure to vitamin E.

Methods A longitudinal birth cohort study was recruited (n=1924). Antenatal ultrasound scan results were identified and the following recorded: crown–rump length (CRL) in the first trimester; femur length (FL) and biparietal diameter (BPD) in the second trimester. Maternal plasma α-tocopherol (vitamin E) was measured at the time of the first trimester scan. At 5 years, wheeze and asthma symptoms were reported by questionnaire, and spirometry was measured.

Results CRL, spirometry and questionnaire data at 5 years were available for 835, 579 and 1145 individuals, respectively. There were positive associations between CRL and forced expiratory volume in 1 s (FEV1; 5 ml increase in FEV1 per mm CRL, p=0.001, n=283), forced vital capacity (FVC; 6 ml increase in FVC per mm CRL, p=0.001) and forced expiratory flow between 25% and 75% of FVC (FEF25–75; 0.008 ml/s increase in FEF25–75 per mm CRL, p=0.023), and inverse relationships with CRL and current wheeze (OR 0.59 per CRL quartile, p=0.026, n=547) and asthma (OR 0.55 per CRL quartile p=0.011). CRL was positively associated with maternal plasma α-tocopherol (p=0.002).

Conclusions These findings support the concept of very early fetal programming of respiratory disease. Maternal vitamin E status may be one determinant for growth of the fetus and fetal lungs during early pregnancy.