ABSTRACT
BACKGROUND: Inadequate pregnancy cobalamin status has been associated with adverse offspring metabolic health in Indian and Nepalese studies. Studies of pregnancy cobalamin status and mid-childhood health outside of Asia are scarce. METHODS: Associations between pregnancy fasting plasma total homocysteine (tHcy), cobalamin status (plasma cobalamin, holotranscobalamin (holoTC), methylmalonic acid (MMA)) and mid-childhood metabolic score (MetSco) ((including fat mass index (zFMI), homeostatic model assessment of insulin resistance (zHOMA-IR) and dyslipidemia (zTG - zHDLc)/2) z-scores)) were investigated in a prospective study of 293 mother-child dyads. RESULTS: Highest versus low-mid pregnancy tHcy tertile was associated with higher mid-childhood MetSco, specifically with higher child zFMI. Stratifying by sex, the maternal tHcy-child MetSco association was limited to boys and confirmed for zFMI and zHOMA-IR. The maternal tHcy-child zFMI association was not mediated by birth weight z-score. First trimester plasma cobalamin was not associated with child outcomes, but other indicators of cobalamin status were. Lowest versus mid-high plasma holoTC tertile was associated with MetSco (specifically zFMI and zHOMA-IR) and highest versus low-mid plasma MMA tertile with higher MetSco and dyslipidemia in boys. CONCLUSIONS: Moderately elevated pregnancy tHcy and low cobalamin status were associated with mid-childhood metabolic score in boys. The pregnancy tHcy-child zFMI association was not mediated by birth weight. IMPACT: Fasting plasma total homocysteine (tHcy) during pregnancy and low cobalamin status during early pregnancy are associated with mid-childhood metabolic score and its components in the offspring. These findings were only significant in male offspring. The study provides new evidence that impaired one carbon metabolism during pregnancy is associated with negative health outcomes in the offspring, in a population with low prevalence of cobalamin deficiency. The maternal-offspring associations were observed in the functional markers of cobalamin status (holotranscobalamin and methylmalonic acid) and tHcy, not with plasma cobalamin concentration. Screening for low pregnancy cobalamin status should be considered.
Subject(s)
Vitamin B 12 Deficiency , Vitamin B 12 , Child , Female , Humans , Male , Pregnancy , Folic Acid , Birth Weight , Methylmalonic Acid , Prospective Studies , Vitamin B 12 Deficiency/diagnosis , Vitamin B 12 Deficiency/epidemiology , HomocysteineABSTRACT
The association between elevated early pregnancy fasting plasma total homocysteine (tHcy) and miscarriage risk was investigated prospectively in participants (n = 544) from the Reus-Tarragona Birth Cohort study. Pregnancy was confirmed before 12 gestational weeks (GW) by ultrasound scan and a fasting blood sample collected. Pregnancies with complications other than miscarriages were excluded. Miscarriages were diagnosed by ultrasound scan and gestational age at the time of miscarriage estimated by embryo size, where possible. Cases in which blood samples were collected more than a week after the miscarriage, or the miscarriage was of known cause, were excluded. Fasting plasma folate, vitamin B12, tHcy, cotinine (biomarker of smoking), red blood cell (RBC) folate, MTHFR 677C > T (rs1801133) and SLC19A1 80G>A (rs1051266) genotypes were determined. The exposed group consisted of participants with first trimester tHcy ≥ P90 (7.1 µmol/L) (n = 57) and unexposed of those with tHcy < P90 (n = 487). Adherence to folic acid supplement recommendations, plasma folate, plasma vitamin B12, RBC folate and prevalence of optimal RBC folate status (≥ 906 µmol/L) were lower in the exposed compared to unexposed group. The prevalences of the MTHFR 677 TT genotype and miscarriage were higher in the exposed group. The relative risks (95% CI) of pregnancy ending in miscarriage were 2.5 (1.1, 5.7) and 2.1 (1.0, 4.5) for participants in the high tHcy and suboptimal RBC folate groups (compared to the reference groups) respectively. Adherence to folic acid supplement recommendations was positively associated, while the MTHFR 677 TT versus CC genotype and smoking versus non-smoking were negatively associated, with RBC folate status.
