Higher maternal body mass index is associated with an increased risk for later type 2 diabetes in offspring

Maternal diabetes independent of BMI is associated with altered accretion of adipose tissue in large for gestational age fetuses

Aim

To analyse the effects of maternal diabetes mellitus (DM) and body mass Index (BMI) on central and peripheral fat accretion of large for gestational age (LGA) offspring.

Methods

This retrospective study included LGA fetuses (n = 595) with ultrasound scans at early (19.23 ± 0.68 weeks), mid (28.98 ± 1.62 weeks) and late (36.20 ± 1.59 weeks) stages of adipogenesis and measured abdominal (AFT) and mid-thigh (TFT) fat as surrogates for central and peripheral adiposity. Women were categorised according to BMI and DM status [pre-gestational (P-DM; n = 59), insulin managed (I-GDM; n = 132) and diet managed gestational diabetes (D-GDM; n = 29)]. Analysis of variance and linear regressions were applied.

Results

AFT and TFT did not differ significantly between BMI categories (normal, overweight and obese). In contrast, AFT was significantly higher in pregnancies affected by D-GDM compared to non-DM pregnancies from mid stage (0.44 mm difference, p = 0.002) and for all DM categories in late stage of adipogenesis (≥ 0.49 mm difference, p < 0.008). Late stage TFT accretion was higher than controls for P-DM and I-GDM but not for D-GDM (0.67 mm difference, p < 0.001; 0.49 mm difference, p = 0.001, 0.56 mm difference, p = 0.22 respectively). In comparison to the early non-DM group with an AFT to TFT ratio of 1.07, the I-GDM group ratio was 1.25 (p < 0.001), which normalised by 28 weeks becoming similar to control ratios.

Conclusions

DM, independent of BMI, was associated with higher abdominal and mid-thigh fat accretion in fetuses. Use of insulin improved central to peripheral fat ratios in fetuses of GDM mothers.

A Genetic Risk Score Improves the Prediction of Type 2 Diabetes Mellitus in Mexican Youths but Has Lower Predictive Utility Compared With Non-Genetic Factors

Background

Type 2 diabetes (T2D) is a multifactorial disease caused by a complex interplay between environmental risk factors and genetic predisposition. To date, a total of 10 single nucleotide polymorphism (SNPs) have been associated with pediatric-onset T2D in Mexicans, with a small individual effect size. A genetic risk score (GRS) that combines these SNPs could serve as a predictor of the risk for pediatric-onset T2D.

Objective

To assess the clinical utility of a GRS that combines 10 SNPs to improve risk prediction of pediatric-onset T2D in Mexicans.

Methods

This case-control study included 97 individuals with pediatric-onset T2D and 84 controls below 18 years old without T2D. Information regarding family history of T2D, demographics, perinatal risk factors, anthropometric measurements, biochemical variables, lifestyle, and fitness scores were then obtained. Moreover, 10 single nucleotide polymorphisms (SNPs) previously associated with pediatric-onset T2D in Mexicans were genotyped. The GRS was calculated by summing the 10 risk alleles. Pediatric-onset T2D risk variance was assessed using multivariable logistic regression models and the area under the receiver operating characteristic curve (AUC).

Results

The body mass index Z-score (Z-BMI) [odds ratio (OR) = 1.7; p = 0.009] and maternal history of T2D (OR = 7.1; p < 0.001) were found to be independently associated with pediatric-onset T2D. No association with other clinical risk factors was observed. The GRS also showed a significant association with pediatric-onset T2D (OR = 1.3 per risk allele; p = 0.006). The GRS, clinical risk factors, and GRS plus clinical risk factors had an AUC of 0.66 (95% CI 0.56-0.75), 0.72 (95% CI 0.62-0.81), and 0.78 (95% CI 0.70-0.87), respectively (p < 0.01).

Conclusion

The GRS based on 10 SNPs was associated with pediatric-onset T2D in Mexicans and improved its prediction with modest significance. However, clinical factors, such the Z-BMI and family history of T2D, continue to have the highest predictive utility in this population.

Environmental and Nutritional Effects Regulating Adipose Tissue Function and Metabolism Across Generations

The unabated rise in obesity prevalence during the last 40 years has spurred substantial interest in understanding the reasons for this epidemic. Studies in mice and humans have demonstrated that obesity is a highly heritable disease; however genetic variations within specific populations have so far not been able to explain this phenomenon to its full extent. Recent work has demonstrated that environmental cues can be sensed by an organism to elicit lasting changes, which in turn can affect systemic energy metabolism by different epigenetic mechanisms such as changes in small noncoding RNA expression, DNA methylation patterns, as well as histone modifications. These changes can directly modulate cellular function in response to environmental cues, however research during the last decade has demonstrated that some of these modifications might be transmitted to subsequent generations, thus modulating energy metabolism of the progeny in an inter- as well as transgenerational manner. In this context, adipose tissue has become a focus of research due to its plasticity, which allows the formation of energy storing (white) as well as energy wasting (brown/brite/beige) cells within the same depot. In this Review, the effects of environmental induced obesity with a particular focus on adipose tissue are discussed.

A Maternal High-Fat Diet Induces DNA Methylation Changes That Contribute to Glucose Intolerance in Offspring

Scope: Overnutrition in utero is a critical contributor to the susceptibility of diabetes by programming, although the exact mechanism is not clear. In this paper, we aimed to study the long-term effect of a maternal high-fat (HF) diet on offspring through epigenetic modifications. Procedures: Five-week-old female C57BL6/J mice were fed a HF diet or control diet for 4 weeks before mating and throughout gestation and lactation. At postnatal week 3, pups continued to consume a HF or switched to a control diet for 5 weeks, resulting in four groups of offspring differing by their maternal and postweaning diets. Results: The maternal HF diet combined with the offspring HF diet caused hyperglycemia and insulin resistance in male pups. Even after changing to the control diet, male pups exposed to the maternal HF diet still exhibited hyperglycemia and glucose intolerance. The livers of pups exposed to a maternal HF diet had a hypermethylated insulin receptor substrate 2 (Irs2) gene and a hypomethylated mitogen-activated protein kinase kinase 4 (Map2k4) gene. Correspondingly, the expression of the Irs2 gene decreased and that of Map2k4 increased in pups exposed to a maternal HF diet. Conclusion: Maternal overnutrition programs long-term epigenetic modifications, namely, Irs2 and Map2k4 gene methylation in the offspring liver, which in turn predisposes the offspring to diabetes later in life.

IL-10 expression in macrophages from neonates born from obese mothers is suppressed by IL-4 and LPS/INFγ

Obese women offspring have a higher risk of developing chronic diseases associated with an altered immune function. We aim to determine, in neonatal monocyte-derived macrophages, whether maternal obesity is associated with an altered expression and DNA methylation of pro- and anti-inflammatory genes, along with a higher pro-inflammatory response. Cord blood from newborns of obese (Ob) and lean (control) women were obtained at delivery. Monocytes were isolated and differentiated into macrophages, in which M1 (LPS/IFNγ) and M2 (IL-4) polarization were assayed. The mRNA levels for TNFα, IL-1β, IL-12A, IL-12B, IL-10, and IL-4R were quantified by qPCR and the DNA methylation of candidate genes determined by pyrosequencing.

RESULTS

Ob-monocytes had decreased levels of mRNA for pro-inflammatory cytokines IL-1β, IL-10, and IL-12B compared with controls. Conversely, Ob-macrophages showed increased levels of mRNA for TNFα, IL-4R, and IL-10 compared with controls. M1 response was comparable between both groups, characterized by an important induction of TNFα and IL-1β. In response to an M2 stimulus, control macrophages showed a decreased expression of inflammatory mediators while Ob-macrophages had an additional suppression of the anti-inflammatory mediator IL-10. Changes in IL-1β (monocytes) and IL-10 (macrophages) in Ob-monocytes were paralleled by changes in their promoter DNA methylation in fetal monocytes. These results suggest that monocyte-derived macrophages from obese newborns show a basal anti-inflammatory phenotype with an unbalanced response to M1 and M2 polarization stimuli. The presence of changes in DNA methylation of key inflammatory genes in neonatal monocytes suggests an intrauterine programing of immune function by maternal obesity.

High perceived social support protects against the intergenerational transmission of obesity: The Cardiovascular Risk in Young Finns Study

AIMS

Our aims were to assess whether offspring social support moderates the relationship between parental body mass index (BMI) and offspring BMI.

METHODS

A prospective design was used with an analytic sample of 1049 participants from Finland (the offspring) who were 35-50years old in 2012 when adulthood BMI was measured. Parental BMI was self-reported at baseline in 1980. Offspring social support was measured in 2007 when participants were 30-45years old. Linear and logistic regression was used to examine whether there was an interaction between parental BMI and offspring social support when predicting offspring BMI in adulthood. An analysis of simple slopes and multilevel growth curve modeling were used to further examine the interaction.

RESULTS

The interaction between maternal BMI and offspring social support was significantly and negatively related to offspring BMI in adulthood (β=-0.068, R(2) change=0.005, p=0.015) in the fully adjusted model which also adjusted for parental occupational status and offspring depressive symptoms. The logistic regression supported these results, with the interaction between maternal overweight (BMI≥25kg/m(2)) and offspring social support negatively associated with offspring overweight in adulthood (odds ratio=0.74, 95% confidence interval, 0.56 to 0.98). The growth curve analysis further demonstrated that high maternal BMI predicts more rapidly rising offspring BMI in those reporting low social support compared to high social support.

CONCLUSIONS

Our results suggest that social support protects against the intergenerational transmission of obesity and therefore presents an important opportunity for obesity prevention efforts.

Role of Conventional Childhood Risk Factors Versus Genetic Risk in the Development of Type 2 Diabetes and Impaired Fasting Glucose in Adulthood: The Cardiovascular Risk in Young Finns Study

OBJECTIVE

We examined whether the addition of novel genetic risk variant data to conventional childhood risk factors improves risk assessment of impaired fasting glucose (IFG) and type 2 diabetes in adulthood.

RESEARCH DESIGN AND METHODS

An association of a weighted genetic risk score (wGRS) based on 73 risk variants with IFG and type 2 diabetes was analyzed in 2,298 participants of the Cardiovascular Risk in Young Finns Study who were followed for 24-31 years from childhood to adulthood. In addition, the value of the wGRS in pediatric prediction of type 2 diabetes was examined.

RESULTS

Of the 2,298 participants, 484 (21.8%) and 79 (3.4%) had IFG or type 2 diabetes in adulthood, respectively. Adjusting for age, sex, baseline BMI, parental diabetes, mother's BMI, fasting insulin concentration, systolic blood pressure, and smoking status, wGRS was associated with an increased risk of IFG (odds ratio 1.64 [95% CI 1.33-2.01] per unit increase in the wGRS) and type 2 diabetes (2.22 [1.43-3.44]). Incorporating wGRS into pediatric risk models improved model discrimination and reclassification properties. Area under the receiver operating curve improved for IFG (from 0.678 to 0.691, P = 0.015), combined IFG and type 2 diabetes outcome (from 0.678 to 0.692, P = 0.007), and type 2 diabetes (from 0.728 to 0.749, P = 0.158). The net reclassification improvement and integrated discrimination improvement were significant for all outcomes.

CONCLUSIONS

A multifactorial approach combining genetic and clinical risk factors may be useful in identifying children at high risk for adult IFG and type 2 diabetes.

Mother's pre-pregnancy BMI is an important determinant of adverse cardiometabolic risk in childhood

OBJECTIVE

Maternal adiposity is associated with poor offspring cardiometabolic health. We aimed to evaluate the relationship of maternal pre-pregnancy body mass index (BMI) on the BMI, body composition and cardiometabolic characteristics of the offspring.

METHODS

Forty offspring of overweight/obese mothers (O-OW) and 28 offspring of normal weight mothers (O-NW) underwent evaluation of body composition, abdominal fat distribution, blood pressure measurement, fasting lipids and an oral glucose tolerance test. The anthropometric and cardiometabolic characteristics of O-OW were compared with those of O-NW, and the relationship to maternal BMI was evaluated.

RESULTS

Subjects (mean age: 12.6 ± 0.4, female: 52.9%) had similar gestational age, birth weight, age, gender, and Tanner stage. However, O-OW had a significantly higher BMI (24.4 ± 1.2 vs. 19.7 ± 0.8 kg/m(2) , p = 0.001), % body fat (31.7 ± 1.6 vs. 24.6 ± 1.1%, p < 0.001), visceral fat (41.9 ± 4.7 vs. 26.1 ± 3.9 cm(2) , p = 0.012) with no difference in lean body mass compared with O-NW. O-OW had lower whole body insulin sensitivity index (WBISI) with an adverse cardiovascular disease risk profile [higher blood pressure (BP), triglycerides to high-density lipoprotein (HDL) ratio, hs-C-reactive protein (CRP) and lower HDL]. In addition to offspring's %body fat (β = -0.60, p < 0.001), maternal pre-pregnancy BMI (β = -0.19, p = 0.046) contributed significantly and independently to the offspring's WBISI (R(2) =0.55, p < 0.001).

CONCLUSIONS

High pre-pregnancy BMI is an important contributor to excess adiposity, insulin resistance, and cardiometabolic disease risk in the offspring during childhood.

Associations of maternal weight status prior and during pregnancy with neonatal cardiometabolic markers at birth: the Healthy Start study

Background

Maternal obesity increases adult offspring risk for cardiovascular disease; however the role of offspring adiposity in mediating this association remains poorly characterized.

Objective

To investigate the associations of maternal pre-pregnant body mass index (maternal BMI) and gestational weight gain (GWG) with neonatal cardio-metabolic markers independent of fetal growth and neonatal adiposity.

Methods

A total of 753 maternal-infant pairs from the Healthy Start study, a large multi-ethnic pre-birth observational cohort were used. Neonatal cardio-metabolic markers included cord blood glucose, insulin, glucose-to-insulin ratio (Glu/Ins), total and high-density lipoprotein cholesterol (HDL-c), triglycerides, free fatty acids and leptin. Maternal BMI was abstracted from medical records or self-reported. GWG was calculated as the difference between the first pre-pregnant weight and the last weight measurement before delivery. Neonatal adiposity (percent fat mass) was measured within 72 hours of delivery using whole body air displacement plethysmography.

Results

In covariate adjusted models, maternal BMI was positively associated with cord blood insulin (p=0.01) and leptin (p<0.001) levels and inversely associated with cord blood HDL-c (p=0.05) and Glu/Ins (p=0.003). Adjustment for fetal growth or neonatal adiposity attenuated the effect of maternal BMI on neonatal insulin, rendering the association non-significant. However, maternal BMI remained associated with higher leptin (p<0.0011), lower HDL-c (p=0.02) and Glu/Ins (p=0.05), independent of neonatal adiposity. GWG was positively associated with neonatal insulin (p=0.02), glucose (p=0.03) and leptin levels (p<0.001) and negatively associated with Glu/Ins (p=0.006). After adjusting for neonatal adiposity, GWG remained associated with higher neonatal glucose (p=0.02) and leptin levels (p=0.02) and lower Glu/Ins (p=0.048).

Conclusions

Maternal weight prior and/or during pregnancy is associated with neonatal cardio-metabolic makers including leptin, glucose, and HDL-c at delivery, independent of neonatal adiposity. Our results suggest that intrauterine exposure to maternal obesity influences metabolic processes beyond fetal growth and fat accretion.

Childhood obesity: Current and novel approaches

The prevalence of childhood obesity has increased over the last fifty years by approximately 5% per decade, and approximately a quarter of all children are now either overweight or obese. These children have a significantly increased risk of many future health problems including adult obesity, type 2 diabetes and heart disease. Despite this relentless increase, common-sense approaches aimed at prevention and treatment have failed to solve the problem. Current approaches at prevention have faced major challenges with some progress in implementing smaller scale programs and social marketing, but little action on broad public policy approaches which often appears unpalatable to society or individual governments. Meanwhile, treatment approaches have mainly focused on lifestyle change, and novel approaches are urgently needed. Prevention needs to shift to improving maternal health prior to conception, with more research focussed on the impact of early years in programming offspring to future overweight/obesity. Likewise, treatment paradigms need to move from simply thinking that obesity can be solved by readdressing diet and activity levels. Novel approaches are needed which take into consideration the complex physiology which regulates early childhood growth and the development of obesity in susceptible individuals.