Interpretation (In light of other evidence)
In our large cohort, the 1st trimester median FPG
level was 82 (78-87) mg/dl. Riskin-Mashiah et al. evaluated the FPG
level throughout pregnancy and demonstrated a mean 3 mg/dl decrease in
early pregnancy compared to the preconception state (from 81 to 78
mg/dl) 11. The same group reported in 2009 that
increased FPG levels at early pregnancy, even within normal levels, were
correlated with increased adverse pregnancy
outcomes12. Our study findings are consistent with
this pattern, showing a similar relationship between increasing
1st trimester FPG levels and the risk of developing
T2DM in the future, paralleling the observed association with perinatal
outcomes.
Our study demonstrated an increased risk for T2DM according to
1st trimester FPG levels within the normal
non-diabetic range. Our results are in line with previous studies that
evaluated FPG levels and risk for T2DM in the general population13,14 and young men 15. For example,
in alignment with our results, Tirosh et al. reported that FPG levels
exceeding 87 mg/dl were linked to an increased risk of future T2DM in a
cohort of 40,000 young adult males, even after accounting for multiple
T2DM risk factors 15.Other studies performed in the
general population suggested a cut-off level of 94 mg/dl as an optimal
point of specificity and sensitivity for predicting T2DM13,14. We can assume that the decrease in FPG levels,
which is suggested in early pregnancy compared to preconception11, as well as other differences in the cohort’s basic
characteristics, may account for these differences in cut-offs.
Furthermore, Specifically to pregnancy, a recently published study had
shown that women with glucose intolerance during pregnancy, even if it
did not meet the standard GDM criteria, had an increased risk of T2DM in
young adulthood 16. Moreover, they observed comparable
risks of developing T2DM among women with GDM and normal FPG levels and
those with isolated abnormal gestational FPG. It is worth noting that in
contrast to our study, the FPG level in that study was documented as
part of oGTT and not during early pregnancy 16.
The recently published TOBOGM study 17 is a randomized
controlled study explored immediate intervention for early GDM or
deferred intervention, according to oGTT results at 24-28 gestational
weeks, and perinatal outcomes. Early GDM was defined by the IADPSG as
1st trimester fasting glucose of 92-125
md/dl6. The study suggested that early intervention
for early GDM led to a modest improvement in composite neonatal outcomes17. However, the study evaluated only women with risk
factors for GDM and did not include maternal or offspring long-term
outcomes.