(P23-20-26) Associations of Selenium and Glutathione Peroxidase Activity With Lipid Profiles During Pregnancy in Rural Bangladesh

Objectives: Lipid metabolism is substantially altered during pregnancy, and selenium (Se) may influence these changes through glutathione peroxidase (GPx), a Se-dependent antioxidant enzyme implicated in lipid oxidation, but evidence during pregnancy is limited.

Methods: Data were from 334 pregnant women enrolled in the Micronutrient Dose Response (MiNDR) randomized controlled trial in which they were allocated to one of four supplementation groups that provided 65, 100, 200, or 300 µg /day of selenium, along with other micronutrients at varying levels, from early pregnancy until birth in rural Bangladesh. Serum Se, plasma GPx activity, and plasma triglyceride (TG) were measured in early (pre-supplementation, ~10 weeks gestational age, GA), mid (~26 weeks GA), and late (~35 weeks GA) pregnancy. Data were pooled across arms and visits. A set of linear mixed-effects models with random intercepts were used to assess mediation by GPx in the association between serum Se and ln-transformed TG as the outcome, adjusted for visit, supplementation group, gestational age, BMI, fasting time, baseline season, maternal age, and parity.

Results: Participants (age: 26.9 ± 5.2 years) had serum Se of 65.7 ± 11.5 µg/L at early, 77.6 ± 20.9 at mid, and 71.5 ± 20.9 at late pregnancy. By a cutoff of < 70 µg/L, 66.5% were Se-deficient at early, 40.5% at mid, and 51.7% at late pregnancy. TG rose from 121 ± 55 mg/dL at early to 240 ± 82 at mid and 294 ± 85 at late pregnancy. Every unit increase in serum Se (µg/L) was associated with 0.16% higher TG (p=0.019). Se was also positively associated with GPx activity across all visits (p < 0.0001). In a separate model that additionally included GPx as a potential mediator, each unit (nmol/min/ml) increase in GPx activity was associated with 0.21% lower TG at early pregnancy (p=0.007) but not at mid or late pregnancy. The association between Se and TG remained significant after adjusting for GPx (p=0.015). However, the estimated mediation effect was close to 0.

Conclusions: The positive association between Se and TG may reflect enhanced lipid availability to support fetal development, but this does not appear to operate through GPx-mediated antioxidant pathways. Future analyses will further examine these associations across additional lipid measures including cholesterol fractions.

Funding Sources: Gates Foundation, Seattle, WA.