Cognitive function in 6- to 12-year-old offspring of women with Type 1 diabetes

Maternal diabetes affects rat offspring retinal structure and function: Sex-specific vulnerabilities at infancy

AIMS

Maternal diabetes negatively impacts the offspring's brain, but little is known about its effects on the retina, which is also part of the central nervous system. We hypothesized that maternal diabetes adversely influences offspring retina development leading to structural and functional deficits.

MAIN METHODS

Retinal structure and function were evaluated at infancy, by optical coherence tomography and electroretinography, in male and female offspring of control, diabetic and diabetic-treated with insulin Wistar rats.

KEY FINDINGS

Maternal diabetes induced a delay in male and female offspring eye-opening, while insulin treatment expedited it. Structural analysis showed that maternal diabetes decreased the thickness of the inner and outer segment layer of photoreceptors in male offspring. Electroretinography also revealed that maternal diabetes decreased the amplitude of scotopic b-wave and flicker response in males, suggesting bipolar cells and cone photoreceptor dysfunction, an effect not observed in females. Conversely, maternal diabetes decreased cone arrestin protein levels in female retinas, while not affecting cone photoreceptor number. Dam insulin therapy was efficient in preventing the offspring photoreceptor changes.

SIGNIFICANCE

Our results suggest that photoreceptors are affected by maternal diabetes, which may account for visual impairments at infancy. Notably, both male and female offspring presented specific vulnerabilities to hyperglycemia in this sensitive period of development.

Effect of exposure to maternal diabetes during pregnancy on offspring's brain cortical thickness and neurocognitive functioning

Little is known about the long-term effects of maternal diabetes during pregnancy (DP), either gestational diabetes or preexisting diabetes (type 1 or type 2), on offspring's brain morphometry and neurocognitive functioning (NCF). This study examined the effect of prenatal exposure to maternal DP on the brain structure and NCF in children between 9 and 10 years of age. This study used cross-sectional neuroimaging and NCF data from the baseline wave of the Adolescent Brain and Cognitive Development® study. Exposure to maternal DP was assigned from the developmental history questionnaire. Differences in the brain cortical thickness (CTh) and five cognitive abilities (executive function, working and episodic memory, processing speed, and language abilities) were examined in diabetes-exposed and diabetes-unexposed children. Linear mixed effect models and generalized linear models were used to adjust for the effect of confounding variables. A total of 9,967 children (718 diabetes-exposed and 9249 unexposed) were included in the analysis. Diabetes-exposed children had lower whole-brain CTh [mean: exposed vs unexposed = 2.725 mm vs 2.732 mm; difference (95%CI): -0.007 mm (-0.013, -0.001)] compared to unexposed children after adjusting for confounding variables. Diabetes-exposed children had lower CTh in most part of the occipital lobe of both hemispheres, right postcentral gyrus, and left superior parietal cortex. Diabetes-exposed children also had lower scores in processing speed task [mean difference (95%CI): -1.7 (-2.8, -0.6)] and total cognition [mean difference (95%CI): -0.6 (-1.2, -0.02)]. Diabetes-exposed children have reduced CTh and NCF during preadolescence, which might have implications for psychomotor development during later life. Prospective studies are needed to confirm our findings.

No Clinically Relevant Memory Effects in Perinatal Hyperglycemia and Hypoglycemia: A 40-Year Follow-Up of a Small Cohort

Maternal diabetes mellitus in pregnancy is associated with impairments in memory functions of the offspring in childhood and adolescence but has not been studied in adulthood. The association of perinatal hypoglycemia with memory has not been studied in adulthood either. The combined sequelae of these two risk factors have not been directly compared. We studied general cognitive ability and memory functions in a prospective follow-up of a cohort born in 1971 to 1974. The sample included participants exposed to prenatal hyperglycemia (n = 24), perinatal hypoglycemia (n = 19), or both (n = 7). It also included controls with no early risks (n = 82). We assessed the participants' Intelligence quotient (IQ), working memory, and immediate and delayed recall of both verbal and visual material at the age of 40. We did not find significant differences in IQ or the memory tests between the groups. We did identify an interaction (p = 0.03) of the early risk with the type of digit span task: compared to the controls, the participants exposed to perinatal hypoglycemia had a larger difference between the forward digit span, a measure of attention, and the backward digit span, a measure of working memory processing (p = 0.022). The interaction remained significant when birth weight was controlled for (p = 0.026). Thus, in this small cohort, prenatal hyperglycemia, perinatal hypoglycemia, and their combination appeared relatively benign disorders. The association of these conditions with neurocognitive impairments in adulthood remains unconfirmed. The significance of the working memory difference needs to be verified with a larger sample.

School performance in Danish children exposed to maternal type 1 diabetes in utero: A nationwide retrospective cohort study

BACKGROUND

Conflicting results have been reported concerning possible adverse effects on the cognitive function of offspring of mothers with type 1 diabetes (O-mT1D). Previous studies have included offspring of parents from the background population (O-BP), but not offspring of fathers with type 1 diabetes (O-fT1D) as the unexposed reference group.

METHODS AND FINDINGS

This is a population-based retrospective cohort study from 2010 to 2016. Nationally standardized school test scores (range, 1 to 100) were obtained for public school grades 2, 3, 4, 6, and 8 in O-mT1D and compared with those in O-fT1D and O-BP. Of the 622,073 included children, 2,144 were O-mT1D, and 3,474 were O-fT1D. Multiple linear regression models were used to compare outcomes, including the covariates offspring with type 1 diabetes, parity, number of siblings, offspring sex, smoking during pregnancy, parental age, and socioeconomic factors. Mean test scores were 54.2 (standard deviation, SD 24.8) in O-mT1D, 54.4 (SD 24.8) in O-fT1D, and 56.4 (SD 24.7) in O-BP. In adjusted analyses, the mean differences in test scores were -1.59 (95% CI -2.48 to -0.71, p < 0.001) between O-mT1D and O-BP and -0.78 (95% CI -1.48 to -0.08, p = 0.03) between O-fT1D and O-BP. No significant difference in the adjusted mean test scores was found between O-mT1D and O-fT1D (p = 0.16). The study's limitation was no access to measures of glycemic control during pregnancy.

CONCLUSIONS

O-mT1D achieved lower test scores than O-BP but similar test scores compared with O-fT1D. Glycemic control during pregnancy is essential to prevent various adverse pregnancy outcomes in women with type 1 diabetes. However, the present study reduces previous concerns regarding adverse effects of in utero hyperglycemia on offspring cognitive function.

The long-term metabolic and neurocognitive risks in offspring of women with type 1 diabetes mellitus

AIMS

Previous studies have evaluated long-term metabolic and neurocognitive outcomes in offspring of women with diabetes. However, many studies did not differentiate between different types of diabetes. We aimed to specifically evaluate both metabolic and neurocognitive outcomes in offspring of women with type 1 diabetes mellitus (OT1D).

METHODS

We conducted an extensive literature search on PubMed between February 2020 and September 2020. We performed a scoping review including 12 retrospective cohort studies, 15 prospective cohort studies, one case-control study and one cross-sectional study, comparing long-term metabolic and neurocognitive outcomes between OT1D and a control group.

RESULTS

OT1D had a higher body mass index and an increased risk for overweight and obesity compared to offspring of mothers without diabetes. A limited number of studies showed a higher risk for (pre)diabetes, higher rates of non-alcoholic fatty liver disease and metabolic syndrome in OT1D. Index offspring had in general similar intelligence and academic achievement as control children but a higher risk for attention deficit and hyperactivity disorders. Data were conflicting concerning the increased risk for autism spectrum disorders. There is limited evidence suggesting that female offspring have more often unfavorable metabolic parameters, while male offspring are more at risk for hyperactivity/impulsivity.

CONCLUSION

Maternal type 1 diabetes mellitus is associated with an increased risk of several metabolic complications and neurobehavioral disorders in the offspring. Increased attention for long-term complications in this population is needed. Further research is needed to evaluate whether improved glycemic control in pregnancy can reduce these long-term complications.

Psychosocial adjustment of young offspring in the context of parental type 1 and type 2 diabetes: a systematic review

AIMS

To identify all available research on psychosocial outcomes in young people who have a parent with type 1 or type 2 diabetes.

METHODS

Embase, PsychInfo, Scopus, Web of Science, PubMed and ProQuest Social Sciences databases were searched according to a registered study protocol (PROSPERO CRD42019125301). Quality assessment, data extraction and data synthesis were carried out.

RESULTS

The initial search yielded 11 599 articles, 10 of which met the criteria for this review: six for type 1 diabetes and four for type 2 diabetes. Through thematic analysis, five categories emerged related to offspring psychosocial adjustment: offspring mental health, offspring physical health, offspring personal resources, parental illness characteristics and offspring caregiving. Overall, there were few studies focusing solely on the effects of parental type 1 and type 2 diabetes on young people. From the limited available research, there is weak evidence suggesting both parental types of diabetes can adversely impact young offspring. Illness-related variables were only explored in parental type 1 diabetes studies, while offspring caregiving was only examined in parental type 2 diabetes studies.

CONCLUSIONS

Research on the effects of parental diabetes on young people is scarce; however, there was weak evidence to suggest some young people are at risk of adverse psychosocial impacts. Given the rise in the incidence of diabetes globally, there is a pressing public health need to conduct more rigorously designed studies to ascertain the extent to which young people are at risk of mental and physical health problems and to identify risk and protective factors associated with youth adjustment in the context of parental diabetes.

Sex differences in offspring neurodevelopment, cognitive performance and microglia morphology associated with maternal diabetes: Putative targets for insulin therapy

Diabetes during pregnancy has been shown to affect the central nervous system (CNS) of the offspring, resulting in short- and long-term adverse effects. Children of diabetic mothers are more likely to develop cognitive impairment, also having increased susceptibility to psychiatric disorders. Microglia, the immune cells of the CNS, work as sensors of environmental changes, namely metabolic challenges, as early as the intrauterine period. During this period, microglia is actively involved in processes of neurogenesis, synaptic pruning and detection of any environmental alteration that may impact brain development. The remarkable sex dimorphism in neurodevelopment, as well as sex differences in the morphology and immune function of microglia during development, led us to clarify if maternal diabetes affects specific behavioral traits and microglia morphology during infancy in a sex-specific manner. Another important goal of this study was to clarify if insulin, the gold standard treatment of diabetes during gestation, could prevent maternal diabetes-induced behavioral changes, as well as microglia morphology, also considering sex specificities. Other molecular and cellular players potentially involved in the link between changes in metabolism and behavior were also analyzed in the hippocampus, a brain region implicated in cognition and other behavioral outcomes. Diabetes during pregnancy globally delayed female and male offspring development and was associated with impairments in recognition memory, but only in female offspring. In line with these results, at early and late infancy, some molecular and cellular markers were altered in offspring hippocampus in a sex-specific manner. The strict control of glycemia by insulin during pregnancy prevented most of the negative effects induced by uncontrolled hyperglycemia. Notably, insulin administration to diabetic dams may also modulate offspring development in a way that differs from what is observed in physiological conditions, since it promoted the expedited acquisition of developmental milestones and of discrimination ability at memory test, also inducing a hyper-ramification of male and female hippocampal microglia. Importantly, this study highlights the importance of analyzing the impact of maternal diabetes and insulin therapy, taking into account sex differences, since male and female present different vulnerabilities to hyperglycemia in this critical period of life.

Systemic endocrinopathies (thyroid conditions and diabetes): impact on postnatal life of the offspring

Fetal programming may influence childhood and adult life, determining the risk of specific diseases. During earlier stages of pregnancy, the transfer of maternal thyroid hormones to the fetus is vital for adequate neurologic development. The presence of severe maternal thyroid dysfunction, particularly severe iodine deficiency, is devastating, leading to irreversible neurologic sequelae. Moreover, mild maternal thyroid conditions, such as a mild-to-moderate iodine deficiency, may also lead to milder neurologic and behavioral conditions later during the life of the offspring. Maternal dysglycemia due to pregestational or gestational diabetes mellitus is another common situation in which fetal development encounters a hostile environment. Hyperglycemia in utero may trigger metabolic conditions in the offspring, including abnormalities of glucose tolerance and weight excess. Physicians assisting pregnant women have to be aware about these conditions, because they may go unnoticed if not properly screened. Because an early diagnosis and appropriate management may prevent most of the possible negative consequences for the progeny, the prevention, early diagnosis, and proper management of these endocrine conditions should be offered to all women undergoing pregnancy. Here, we comprehensively review the current evidence about the effects of maternal thyroid dysfunction and maternal dysglycemia on the cognitive function and carbohydrate metabolism in the offspring, two prevalent conditions of utmost importance for the child's health and development.

Neurocognitive and behavioural outcomes in offspring exposed to maternal pre-existing diabetes: a systematic review and meta-analysis

AIMS/HYPOTHESIS

We performed a systematic review and meta-analysis to determine whether exposure to maternal pre-existing diabetes in pregnancy is associated with neurocognitive or behavioural outcomes in offspring.

METHODS

We searched MEDLINE, EMBASE, PsychINFO, the Cochrane Database of Systematic Reviews and Scopus for studies that examined any neurocognitive or behavioural outcomes in offspring of mothers with pre-existing diabetes in pregnancy in accordance with a published protocol (PROSPERO CRD42018109038). Title and abstract review, full-text review and data extraction were performed independently and in duplicate. Risk of bias was assessed using the Newcastle-Ottawa scale. Meta-analyses of summary measures were performed using random-effects models.

RESULTS

Nineteen articles including at least 18,681 exposed and 2,856,688 control participants were identified for inclusion. Exposure to maternal pre-existing diabetes in pregnancy was associated with a lower pooled intelligence quotient in the offspring (pooled weighted mean difference -3.07 [95% CI -4.59, -1.55]; I2 = 0%) and an increased risk of autism spectrum disorders (effect estimate 1.98 [95% CI 1.46, 2.68]; I2 = 0%). There was also an increased risk of attention deficit/hyperactivity disorder (pooled HR 1.36 [95% CI 1.19, 1.55]; I2 = 0%), though this was based on only two studies. Although most studies were found to be high quality in terms of participant selection, in many studies, comparability of cohorts and adequacy of follow-up were sources of bias.

CONCLUSIONS/INTERPRETATION

There is evidence to suggest that in utero exposure to maternal pre-existing diabetes is associated with some adverse neurocognitive and behavioural outcomes. It remains unclear what the role of perinatal factors is and the degree to which other environmental factors contribute to these findings.

Brain heparan sulphate proteoglycans are altered in developing foetus when exposed to in-utero hyperglycaemia

In-utero exposure of foetus to hyperglycaemic condition affects the growth and development of the organism. The brain is one of the first organs that start to develop during embryonic period and glycosaminoglycans (GAGs) and proteoglycans (PGs) are one of the key molecules involved in its development. But studies on the effect of hyperglycaemic conditions on brain GAGs/PGs are few and far between. We, therefore, looked into the changes in brain GAGs and PGs at various developmental stages of pre- and post-natal rats from non-diabetic and diabetic mothers as well as in adult rats induced with diabetes using a diabetogenic agent, Streptozotocin. Increased expression of GAGs especially that of heparan sulphate class in various developmental stages were observed in the brain as a result of in-utero hyperglycaemic condition but not in that of adult rats. Changes in disaccharides of heparan sulphate (HS) were observed in various developmental stages. Furthermore, various HSPGs namely, syndecans-1 and -3 and glypican-1 were overexpressed in offspring from diabetic mother. However, in adult diabetic rats, only glypican-1 was overexpressed. The offsprings from diabetic mothers became hyperphagic at the end of 8 weeks after birth which can have implications in the long run. Our results highlight the likely impact of the in-utero exposure of foetus to hyperglycaemic condition on brain GAGs/PGs compared to diabetic adult rats.

Brain Development in Fetuses of Mothers with Diabetes: A Case-Control MR Imaging Study

BACKGROUND AND PURPOSE

Offspring exposed to maternal diabetes are at increased risk of neurocognitive impairment, but its origins are unknown. With MR imaging, we investigated the feasibility of comprehensive assessment of brain metabolism (1H-MRS), microstructure (DWI), and macrostructure (structural MRI) in third-trimester fetuses in women with diabetes and determined normal ranges for the MR imaging parameters measured.

MATERIALS AND METHODS

Women with singleton pregnancies with diabetes (n = 26) and healthy controls (n = 26) were recruited prospectively for MR imaging studies between 34 and 38 weeks' gestation.

RESULTS

Data suitable for postprocessing were obtained from 79%, 71%, and 46% of women for 1H-MRS, DWI, and structural MRI, respectively. There was no difference in the NAA/Cho and NAA/Cr ratios (mean [SD]) in the fetal brain in women with diabetes compared with controls (1.74 [0.79] versus 1.79 [0.64], P = .81; and 0.78 [0.28] versus 0.94 [0.36], P = .12, respectively), but the Cho/Cr ratio was marginally lower (0.46 [0.11] versus 0.53 [0.10], P = .04). There was no difference in mean [SD] anterior white, posterior white, and deep gray matter ADC between patients and controls (1.16 [0.12] versus 1.16 [0.08], P = .96; 1.54 [0.16] versus 1.59 [0.20], P = .56; and 1.49 [0.23] versus 1.52 [0.23], P = .89, respectively) or volume of the cerebrum (243.0 mL [22.7 mL] versus 253.8 mL [31.6 mL], P = .38).

CONCLUSIONS

Acquiring multimodal MR imaging of the fetal brain at 3T from pregnant women with diabetes is feasible. Further study of fetal brain metabolism in maternal diabetes is warranted.

Long-term Cognitive Implications of Intrauterine Hyperglycemia in Adolescent Offspring of Women With Type 1 Diabetes (the EPICOM Study)

OBJECTIVE

Exposure to maternal diabetes in utero may have a negative impact on the developing brain. The objective was to examine long-term cognitive consequences of intrauterine hyperglycemia in adolescent offspring of women with type 1 diabetes and to ascertain a possible association with maternal HbA1c.

RESEARCH DESIGN AND METHODS

Offspring of a prospectively followed cohort of women with type 1 diabetes (n = 277) participated in a follow-up examination at the age of 13-19 years. A control group from the background population was identified (n = 301). Cognitive function was evaluated using Reynolds Intellectual Assessment Scales and classified into indices of composite intelligence, verbal and nonverbal intelligence, and composite memory. Frequencies of reading and writing problems and attendance to classes for children with learning difficulties were assessed.

RESULTS

Offspring of women with type 1 diabetes scored lower in all normalized and standardized intelligence indices compared with controls: composite intelligence (95.7 vs. 100, P = 0.001), verbal intelligence (96.2 vs. 100, P = 0.004), nonverbal intelligence (96.4 vs. 100, P = 0.008), and composite memory (95.7 vs. 100, P = 0.001). A higher frequency of diabetes-exposed offspring had parent-reported learning difficulties in primary school. Differences between groups remained after adjustment for confounders and potential mediators. We found no direct association between maternal HbA1c and offspring cognitive function in the exposed group.

CONCLUSIONS

Adolescent offspring of women with type 1 diabetes had lower cognitive function compared with a control group, also after adjustment for confounders and potential mediators. These differences may reflect direct harmful effects of maternal diabetes on neurodevelopment in the offspring.

Academic Achievement in Primary School in Offspring Born to Mothers With Type 1 Diabetes (the EPICOM Study): A Register-Based Prospective Cohort Study

OBJECTIVE

This study examined the effect of maternal pregestational type 1 diabetes on offspring primary school performance.

RESEARCH DESIGN AND METHODS

We performed a prospective combined clinical and register-based cohort study comparing primary school performance in offspring (n = 707) of women with pregestational type 1 diabetes with matched control offspring (n = 60,341). We also examined the association between HbA1c levels during pregnancy and later school performance among offspring born to women with pregestational type 1 diabetes.

RESULTS

Offspring of mothers with pregestational type 1 diabetes obtained similar school grades as control offspring when finishing primary school (regression coefficient [β] = -0.13; 95% CI = -0.30 to 0.03; P = 0.12). Adjusting for parental education also resulted in an insignificant difference between the two groups (β = -0.07; 95% CI = -0.23 to 0.09; P = 0.37). Among offspring of women with type 1 diabetes, increasing maternal HbA1c pregestationally and throughout the pregnancy was associated with lower average school grades. Offspring born to mothers with good glycemic control in the third trimester obtained higher average school grades compared with control offspring. The opposite applied to offspring born to mothers with inadequate glycemic control, who obtained significantly lower average school grades compared with control offspring.

CONCLUSIONS

Offspring of mothers with pregestational type 1 diabetes obtained similar average grades when finishing primary school compared with matched control offspring. Among offspring of women with type 1 diabetes, we found a consistent negative association between maternal HbA1c in pregnancy and primary school grades. However, whether this association reflects a direct causal influence of intrauterine hyperglycemia is uncertain.

Hypoglycemia induced by insulin as a triggering factor of cognitive deficit in diabetic children

This paper provides an overview of insulin-induced hypoglycemia as a triggering factor of cognitive deficit in children with type 1 diabetes mellitus. For this purpose, databases from 1961 to 2013 were used with the objective of detecting the primary publications that address the impact of hypoglycemia on cognitive performance of diabetic children. The results obtained from experimental animals were excluded. The majority of studies demonstrated that the cognitive deficit in diabetic children involves multiple factors including duration, intensity, severity, and frequency of hypoglycemia episodes. Additionally, age at the onset of type 1 diabetes also influences the cognitive performance, considering that early inception of the disease is a predisposing factor for severe hypoglycemia. Furthermore, the results suggest that there is a strong correlation between brain damage caused by hypoglycemia and cognitive deterioration. Therefore, a more cautious follow-up and education are needed to impede and treat hypoglycemia in children with diabetes mellitus.

Maternal diabetes in pregnancy and offspring cognitive ability: sibling study with 723,775 men from 579,857 families

AIMS/HYPOTHESIS

The aim of this study was to investigate the association between maternal diabetes in pregnancy and offspring cognitive ability and also to assess whether the association was due to intrauterine mechanisms or shared familial characteristics.

METHODS

We linked national registers and conducted a prospective cohort study of singleton Swedish-born men to explore associations between maternal pregnancy diabetes and educational achievement at age 16 years, the age of completing compulsory education in Sweden (n = 391,545 men from 337,174 families, graduating in 1988-1997 and n = 326,033 men from 282,079 families, graduating in 1998-2009), and intelligence quotient (IQ) at the mandatory conscription examination at 18 years of age (n = 664,871 from 543,203 families).

RESULTS

Among non-siblings, maternal diabetes in pregnancy was associated with lower offspring cognitive ability even after adjustment for maternal age at birth, parity, education, early-pregnancy BMI, offspring birth year, gestational age and birthweight. For example, in non-siblings, the IQ of men whose mothers had diabetes in their pregnancy was on average 1.36 points lower (95% CI -2.12, -0.60) than men whose mothers did not have diabetes. In comparison, we found no such association within sibships (mean difference 1.70; 95% CI -1.80, 5.21).

CONCLUSIONS/INTERPRETATION

The association between maternal diabetes in pregnancy and offspring cognitive outcomes is likely explained by shared familial characteristics and not by an intrauterine mechanism.

Long-term health outcomes in offspring born to women with diabetes in pregnancy

In this review, we critically assess recent evidence from human studies regarding the potential implications of exposure to maternal diabetes in-utero for long-term adiposity, cardiometabolic outcomes, and cognitive ability of the offspring. Evidence supports a direct causal role for exposure to maternal diabetes in utero in determining offspring long-term greater adiposity and adverse cardiometabolic health. Although a majority of observational studies report associations of exposure to maternal pregnancy diabetes with lower cognitive ability, there is also evidence supporting an opposite 'protective' intrauterine effect of exposure to maternal pregnancy diabetes on offspring cognitive ability. Epigenetic modification has been suggested as a mediator on the pathways from maternal pregnancy diabetes to long-term offspring outcomes and several recent studies that are reviewed here lend some support to this notion, but research in this area is still too novel to be conclusive.

Cognitive function in adult offspring of women with gestational diabetes--the role of glucose and other factors

Objective

We aimed to evaluate cognitive function in adult offspring of women with diet-treated gestational diabetes and to study potential associations with maternal glucose values.

Materials and Methods

In 2003–2005 cognitive function was assessed in a cohort of 18–27 year old offspring of women with diet-treated gestational diabetes mellitus (n = 153) and offspring from the background population (n = 118). The main outcome measure was global cognitive score derived from Raven’s Progressive Matrices and three verbal subtests from the Weschler Adult Intelligence Scale. Maternal fasting- and 2-hour blood glucose values from the diagnostic oral glucose tolerance test were used as exposure variables.

Results

Offspring of women with gestational diabetes mellitus had a lower global cognitive score, than offspring from the background population (93.1 vs. 100.0, P<0.001). However, when adjusted for maternal age at delivery, parity, smoking during pregnancy, pre-pregnancy overweight, family social class, parental educational level, gender, birth weight, gestational age, perinatal complications and offspring age at follow-up, the difference was no longer statistically significant. Offspring global cognitive score decreased significantly with increasing maternal fasting glucose (β = −4.5, 95% CI −8.0 to −0.9, P = 0.01) and 2-hour glucose (β = −1.5, −2.9 to −0.2, P = 0.03) in univariate general linear models, but not when adjusted for family social class and parental educational level.

Conclusions

Lower cognitive test scores in adult offspring of women with diet-treated gestational diabetes were explained by well known predictors of cognitive function, but not by maternal hyperglycaemia during pregnancy. We find it reassuring that mild intrauterine hyperglycaemia does not seem to have adverse effect on offspring cognitive function.

Maternal and offspring fasting glucose and type 2 diabetes-associated genetic variants and cognitive function at age 8: a Mendelian randomization study in the Avon Longitudinal Study of Parents and Children

Background

In observational epidemiological studies type 2 diabetes (T2D) and both low and high plasma concentrations of fasting glucose have been found to be associated with lower cognitive performance. These associations could be explained by confounding.

Methods

In this study we looked at the association between genetic variants, known to be robustly associated with fasting glucose and T2D risk, in the mother and her offspring to determine whether there is likely to be a causal link between early life exposure to glucose and child’s intelligence quotient (IQ) scores in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. We generated a fasting glucose (FGGRS) and a T2D (T2DGRS) genetic risk score and used them in a Mendelian randomization approach.

Results

We found a strong correlation between the FGGRS and fasting glucose plasma measurements that were available for a subset of children, but no association of either the maternal or the offspring FGGRS with child’s IQ was observed. In contrast, the maternal T2DGRS was positively associated with offspring IQ.

Conclusions

Maternal and offspring genetic variants which are associated with glucose levels are not associated with offspring IQ, suggesting that there is unlikely to be a causal link between glucose exposure in utero and IQ in childhood. Further exploration in even larger cohorts is required to exclude the possibility that our null findings were due to a lack of statistical power.

Associations of existing diabetes, gestational diabetes, and glycosuria with offspring IQ and educational attainment: the Avon Longitudinal Study of Parents and Children

Introduction. Results from studies examining associations of maternal diabetes in pregnancy with offspring cognitive outcomes have been inconclusive. Methods. We used data from the Avon Longitudinal Study of Parents and Children, a UK prospective pregnancy cohort. Outcomes were School Entry Assessment (SEA) scores (age 4, N = 6, 032) and WISC-III IQ (age 8, N = 5, 282–5,307) and General Certificate of Secondary Education (GCSE) results (age 16, N = 7, 615). Results. Existing diabetes, gestational diabetes, and, to a lesser extent, glycosuria were associated with lower offspring SEA scores (age 4), IQ (age 8), and GCSE results (age 16) even when adjusting for offspring sex, maternal age, prepregnancy BMI, smoking in pregnancy, parity, caesarean section, maternal education, and occupational social class. Offspring of mothers with existing diabetes had a threefold risk of achieving no GCSEs graded A*-C, whilst offspring of women with gestational diabetes had, on average, a five point lower IQ compared to offspring of women with no diabetes or glycosuria. Conclusions. Maternal diabetes in pregnancy is consistently associated with lower offspring cognition and educational attainment though confidence intervals were wide. The weaker associations with glycosuria suggest a dose-dependent adverse association with IQ.