The association between age at menarche and later risk of gestational diabetes is mediated by insulin resistance

Mendelian randomization identifies age at menarche as an independent causal effect factor for gestational diabetes mellitus

AIMS

The relationship between age at menarche (AAM) and gestational diabetes mellitus (GDM) risk is still inconclusive. This Mendelian randomization (MR) analysis was used to assess systematically the causal relationship between AAM and GDM risk in human beings.

MATERIALS AND METHODS

Single-nucleotide polymorphisms associated with AAM, oestradiol levels, sex hormone-binding globulin (SHBG) levels and bioavailable testosterone (BioT) levels were screened via the genome-wide association study enrolling individuals of European descent. Summary-level data for GDM (123 579 individuals) were extracted from the UK Biobank. An inverse-variance-weighted method was used for the primary MR analysis. Sensitivity analyses were examined via MR-Egger regression, heterogeneity tests, pleiotropy tests and leave-one-out tests. The directionality that exposure causes the outcome was verified using the MR-Steiger test.

RESULTS

Genetically predicted early AAM was found to have a causal positive association with a higher risk of GDM (odds ratio = 0.798, 95% confidence interval = 0.649-0.980, p = .031). In the multivariable MR analysis adjusted for oestradiol, SHBG and BioT levels, the causal association between AAM and GDM risk remained (odds ratio = 0.651, 95% confidence interval = 0.481-0.881, p = .006). A 1-SD increase in SHBG or BioT levels was significantly associated with a 41.4% decrease or 20.8% increase in the overall GDM risk (p = 3.71E-05 and .040), respectively. However, after controlling for AAM, oestradiol levels and BioT levels by multivariable MR analysis, there was no direct causal effect of SHBG levels on GDM risk (p = .084). Similarly, after adjusting for AAM, oestradiol levels and SHBG levels by multivariable MR analysis, there was no direct causal effect of BioT levels on the risk of GDM (p = .533). In addition, no direct causal association was identified between oestradiol levels and GDM risk in univariable MR analysis or multivariable MR analysis.

CONCLUSION

Genetic variants predisposing individuals to early AAM were independently associated with higher GDM risk. Further research is required to understand the mechanisms underlying this putative causative association. In addition, AAM may be helpful in clinical practice to identify women at risk for GDM; pregnant women who are young for menarche may need to take precautions before GDM develops.

Development and Validation of Risk Prediction Models for Gestational Diabetes Mellitus Using Four Different Methods

Gestational diabetes mellitus (GDM), a common perinatal disease, is related to increased risks of maternal and neonatal adverse perinatal outcomes. We aimed to establish GDM risk prediction models that can be widely used in the first trimester using four different methods, including a score-scaled model derived from a meta-analysis using 42 studies, a logistic regression model, and two machine learning models (decision tree and random forest algorithms). The score-scaled model (seven variables) was established via a meta-analysis and a stratified cohort of 1075 Chinese pregnant women from the Northwest Women's and Children's Hospital (NWCH) and showed an area under the curve (AUC) of 0.772. The logistic regression model (seven variables) was established and validated using the above cohort and showed AUCs of 0.799 and 0.834 for the training and validation sets, respectively. Another two models were established using the decision tree (DT) and random forest (RF) algorithms and showed corresponding AUCs of 0.825 and 0.823 for the training set, and 0.816 and 0.827 for the validation set. The validation of the developed models suggested good performance in a cohort derived from another period. The score-scaled GDM prediction model, the logistic regression GDM prediction model, and the two machine learning GDM prediction models could be employed to identify pregnant women with a high risk of GDM using common clinical indicators, and interventions can be sought promptly.

Risk Factors Screening for Gestational Diabetes Mellitus Heterogeneity in Chinese Pregnant Women: A Case-Control Study

PURPOSE

To study the risk factors of gestational diabetes mellitus (GDM) heterogeneity, and to evaluate the correlation between the risk factors and obesity.

METHODS

We performed a case-control study of 452 women with GDM and 516 women with normal glucose tolerance (NGT) at the first and second trimester. We defined GDM women as GDM-resistance subtype, GDM-dysfunction subtype, and GDM-mixed subtype, according to their simultaneous insulin-release test with predominant insulin-sensitivity defect, insulin-secretion defect, or both defects.

RESULTS

We found that higher maternal age, family history of diabetes, the elevated level of fasting blood glucose in the first trimester (≥5.1 mmol/L) were risk factors of all GDM subtypes. Pre-pregnancy overweight/obesity and the increased gestational weight gain (GWG) in the first-trimester are risk factors of the GDM-resistance subtype. Indicators including younger age at first menstruation, the elevated levels of alanine aminotransferase (ALT), total bile acid (TBA), triglyceride (TG), and the decreased level of high-density lipoprotein cholesterol (HDL-C) are risk factors of the GDM-resistance subtype. However, the associations between those risk factors and GDM-resistance subtype attenuated after adjusted by pre-pregnancy body mass index (pre-BMI) and gestational weight gain (GWG) in the first trimester. Nonalcoholic fatty liver disease (NAFLD) and the improved level of TG are independent risk factors for the GDM-resistance subtype and the GDM-mixed subtype, respectively.

CONCLUSION

Women with GDM exhibited heterogeneity based on glycemic physiology and their risk factors are not all the same. Some obesity-related risk factors are specific to the GDM-resistance subtype, which are mediated by pre-pregnancy overweight/obesity and the elevated GWG the first-trimester.

Pubertal timing in boys and girls born to mothers with gestational diabetes mellitus: a systematic review

CONTEXT

The incidence of gestational diabetes mellitus (GDM) has been on the rise, driven by maternal obesity. In parallel, pubertal tempo has increased in the general population, driven by childhood obesity.

OBJECTIVE

To evaluate the available evidence on pubertal timing of boys and girls born to mothers with GDM.

DATA SOURCES

We searched MEDLINE, EMBASE, CINAHL Plus, Cochrane library and grey literature for observational studies up to October 2019.

STUDY SELECTION AND EXTRACTION

Two reviewers independently selected studies, collected data and appraised the studies for risk of bias. Results were tabulated and narratively described as reported in the primary studies.

RESULTS

Seven articles (six for girls and four for boys) were included. Study quality score was mostly moderate (ranging from 4 to 10 out of 11). In girls born to mothers with GDM, estimates suggest earlier timing of pubarche, thelarche and menarche although for each of these outcomes only one study each showed a statistically significant association. In boys, there was some association between maternal GDM and earlier pubarche, but inconsistency in the direction of shift of age at onset of genital and testicular development and first ejaculation. Only a single study analysed growth patterns in children of mothers with GDM, describing a 3-month advancement in the age of attainment of peak height velocity and a slight increase in pubertal tempo.

CONCLUSIONS

Pubertal timing may be influenced by the presence of maternal GDM, though current evidence is sparse and of limited quality. Prospective cohort studies should be conducted, ideally coupled with objective biochemical tests.

Early menarche is associated with insulin resistance in advanced maternal age before delivery

Purpose: With the wide implementation of the universal two-child policy in China, the number of pregnant women in advanced maternal age (AMA) will increase gradually. We aimed to assess the association between age at menarche (AAM) and insulin resistance (IR) before delivery in AMA. Methods: A total of 80 pregnant women in AMA were consecutively enrolled before delivery in Zhongda hospital. Pregnant women were stratified into early menarche group and late menarche group according to the age of regular menstruation (about 13 years). At delivery, serum glucose and lipid levels were measured. IR was calculated by the method of homeostasis model assessment 2(HOMA2). Results: The fasting blood insulin (17.68(9.72-36.71) and 10.35(7.76-15.10), respectively; p = .006) and HOMA-IR (2.08(1.18-4.37) and 1.24(0.89-1.78), respectively; p = .005) were higher in early menarche group than in late menarche group. AAM was inversely associated with HOMA-IR in AMA (r= -0.27, p = .014). In the multivariable analysis, AAM in late menarche group was negatively related to the level of HOMA-IR compared to those in early menarche group (β= -2.275, p≤.0001). Conclusions: Taken together, our findings suggest that AAM was inversely associated with HOMA-IR in AMA. Furthermore, pregnant women in AMA with early menarche might have higher HOMA-IR levels than those with late menarche. Clinical trial registration: Chinese Clinical Trial Registry (No. ChiCTR-RRC-16008714), retrospectively registered.

Temporal trends without seasonal effects on gestational diabetes incidence relate to reductions in indices of insulin secretion: the Cambridge Baby Growth Study

AIMS

The incidence of gestational diabetes has been reported to have risen over the first decade of this century. Some studies have also found it to vary with seasons of the year. We investigated temporal and seasonal trends on gestational diabetes incidence in a single-centre cohort study from Cambridge, UK, and attempted to explain trends using associated risk factors.

METHODS

Using a cosinor model, we tested both temporal and seasonal trends in gestational diabetes incidence in 1074 women recruited to the Cambridge Baby Growth Study in 2001-2009 who underwent oral glucose tolerance tests around week 28 of pregnancy.

RESULTS

There was a temporal increase in gestational diabetes incidence over the course of recruitment to this study [0.014 (0.005, 0.022) proportional increase per year, p = 2.1 × 10^-3], but no seasonal effect (p = 0.7). HOMA B [- 0.015 (- 0.025, - 0.005) per year, p = 3.0 × 10^-3] and the insulin disposition index [- 0.036 (- 0.060, - 0.013) per year, p = 3.0 × 10^-3], unlike HOMA S, showed negative temporal trends. Risk factor analyses showed a concomitant temporal slight increase in the index of multiple deprivation [0.191 (0.138, 0.257) units per year, p = 4.6 × 10^-10]. This index was positively associated with HOMA B (p = 6.1 × 10^-5) but not directly with gestational diabetes (p = 0.6), HOMA S (p = 0.2) or the insulin disposition index (p = 0.4).

CONCLUSIONS

In this cohort, there were temporal, but not seasonal, increases in gestational diabetes incidence between the years 2001 and 2009, which appeared to be related more to reductions in insulin secretion than sensitivity. Possible mediators of this link include confounding factors related to deprivation.

Age at Menarche and Blood Pressure in Pregnancy

Objectives

To investigate whether age at menarche is related to maternal blood pressure in pregnancy and, if so, whether obesity and insulin resistance can modify the associations.

Study Design

Analysis of data collected from 438 pregnant women from the longitudinal and prospective Cambridge Baby Growth Study.

Main Outcome

Testing associations between questionnaire-derived age at menarche and blood pressure measurements in pregnancy collected from hospital notes, and investigating whether any associations were altered by maternal pre-pregnancy body mass index (BMI) and insulin resistance.

Measures

Mean arterial blood pressure at four time points across pregnancy, age at menarche, (Homeostasis Model Assessment) insulin resistance around week 28 of pregnancy.

Results

For each increased year in age at menarche there was a drop in mean arterial blood pressure (mmHg) of 0.6 at 11.9 weeks, 0.9 at 31.4 and 37.0 weeks, and 0.4 at 38.8 weeks (a maximal difference of over 7 mmHg across extremes of AAM). Each association was attenuated by both maternal pre-pregnancy BMI and insulin resistance.

Conclusions

Age at menarche is negatively associated with future blood pressure in pregnancy, so those with the earliest age at menarche have the highest blood pressures. Either these associations may be mediated by links between age at menarche and obesity/insulin resistance, or there may be a confounder (e.g. systemic inflammation) that links age at menarche to each of them.

Age at menarche and the future risk of gestational diabetes: a systematic review and dose response meta-analysis

Published studies show an inconsistent association between age at menarche and the subsequent risk of developing gestational diabetes mellitus when pregnant. This systematic review and meta-analysis was performed to clarify any trends in this association in published observational population studies. We searched online databases for relevant studies, entered into them up until June 21st 2017. Five eligible studies were found and a pooled random effects dose response meta-analysis of results from these was conducted. This included coverage of 58,133 pregnancies, from which 3,035 women developed gestational diabetes. There was evidence of a non-linear association between age at menarche and gestational diabetes (overall p = 1.4 × 10^-8; p for non-linearity = 2.4 × 10^-4), along with evidence of relatively low heterogeneity (I² = 25.5%). The largest predicted risk of gestational diabetes was associated with having a low age at menarche; the mean (95% confidence interval) risk relative to that associated with menarche at age 13 years being: 9 years 2.0 (1.6, 2.4), 10 years 1.6 (1.4, 1.9), 11 years 1.3 (1.2, 1.4), 12 years 1.1 (1.1, 1.1), 13 years was the reference, 14 years 1.0 (1.0, 1.0), 15 years 1.1 (0.9, 1.2), 16 years 1.1 (0.9, 1.4). There was evidence of potential publication bias, such that the maximal true relative risk of gestational diabetes, associated with an age at menarche of 9 years, may be closer to 1.6 than 2. Nevertheless, the curvilinear relationship between age at menarche and the future risk of gestational diabetes in pregnancy appears robust.