Tocopherol isoforms may regulate child lung growth and spirometric measures.
To determine the extent to which plasma alpha (α-T) or gamma tocopherol (γ-T) isoform levels in early childhood or in-utero are associated with childhood lung function.
We included 622 participants in the Project Viva cohort, who had lung function at a mid-childhood visit (age 6-10 years old). Maternal and child tocopherol isoform levels were measured by HPLC at second trimester and 3 years old, respectively. Multivariable linear regression models (adjusted for mid-childhood BMI-z-scores, and maternal education, smoking in pregnancy, and prenatal PM particulate exposure), stratified by tertiles of child γ-T, were employed to assess the association of α-T levels with FEV and FVC percent predicted. Similarly, models stratified by child α-T tertile evaluated associations of γ-T levels with lung function. We performed similar analyses with maternal second trimester tocopherol isoform levels.
The maternal second trimester α-T level was median;IQR: 63; 47-82 μM. The early childhood levels were median;IQR: 25; 20-33 μM. In the lowest tertile of early childhood γ-T, children with higher α-T levels (per 10 μM) had higher mid-childhood FEV %-predicted (β=3.09, 95%CI=0.58-5.59), and a higher FVC %-predicted (β=2.77, 95%CI=0.47,5.06). This protective association of α-T was lost at higher γ-T levels. We did not see any consistent associations of second trimester levels of either α-T or γ-T with mid-childhood FEV or FVC.
When γ-T levels were in the lowest tertile, higher early childhood α-T was associated with better lung function at mid-childhood. Second trimester maternal plasma α-T concentration was 3-fold higher than the adult female non-pregnant population.
α-Tocopherol and γ-tocopherol isoforms are potentially modifiable exposures that have differential associations with lung function in later childhood.