Associations of α- and γ-tocopherol during early life with lung function in childhood

Background: Tocopherol isoforms may regulate child lung growth and spirometric measures. Objective: Our aim was to determine the extent to which plasma alpha-tocopherol (alpha-T) or g-tocopherol (gamma-T) isoform levels in early childhood or in utero are associated with childhood lung function. Methods: We included 622 participants in the Project Viva cohort who had lung function at a mid-childhood visit (age 6-10 years). Maternal and child tocopherol isoform levels were measured by HPLC at the second trimester and 3 years of age, respectively. Multivariable linear regression models (adjusted for mid-childhood body mass index z scores, maternal education, smoking in pregnancy, and prenatal particulate matter with diameter of <2.5 micrometers (PM2.5) particulate exposure) stratified by tertiles of child gamma-T level were used to assess the association of alpha-T levels with FEV1 and forced vital capacity (FVC) percent predicted. Similarly, models stratified by child alpha-T tertile evaluated associations of g-T levels with lung function. We performed similar analyses with maternal second trimester tocopherol isoform levels. Results: The median maternal second trimester alpha-T level was 63 mM (interquartile range = 47-82). The median early-childhood level was 25 mM (interquartile range = 20-33 mM). In the lowest tertile of early-childhood gamma-T, children with a higher alpha-T level (per 10 mM) had a higher mid-childhood FEV1 percent predicted (beta = 3.09; 95% CI = 0.58-5.59 and a higher FVC percent predicted (beta = 2.77; 95% CI = 0.47-5.06). This protective association of alpha-T was lost at higher gamma-T levels. We did not see any consistent associations of second trimester levels of either alpha-T or gamma-T with mid-childhood FEV1 or FVC. Conclusion: When gamma-T levels were in the lowest tertile, a higher early-childhood alpha-T level was associated with better lung function at mid-childhood. Second trimester maternal plasma alpha-T concentration was 3-fold higher than in the adult nonpregnant female population.