User login
FAIRFAX, VIRGINIA — Nearly 30 years ago, in a 1995 paper, the British physician-epidemiologist David Barker, MD, PhD, wrote about his fetal origins hypothesis — the idea that programs to address fetal undernutrition and low birth weight produced later coronary heart disease (BMJ 1995;311:171-4).
His hypothesis and subsequent research led to the concept of adult diseases of fetal origins, which today extends beyond low birth weight and implicates the in utero environment as a significant determinant of risk for adverse childhood and adult metabolic outcomes and for major chronic diseases, including diabetes and obesity. Studies have shown that the offspring of pregnant mothers with diabetes have a higher risk of developing obesity and diabetes themselves.
“It’s a whole discipline [of research],” E. Albert Reece, MD, PhD, MBA, of the University of Maryland School of Medicine (UMSOM), said in an interview. “But what we’ve never quite understood is the ‘how’ and ‘why’? What are the mechanisms driving the fetal origins of such adverse outcomes in offspring?
At the biennial meeting of the Diabetes in Pregnancy Study Group of North America (DPSG), investigators described studies underway that are digging deeper into the associations between the intrauterine milieu and longer-term offspring health — and that are searching for biological and molecular processes that may be involved.
The studies are like “branches of the Barker hypothesis,” said Dr. Reece, former dean of UMSOM and current director of the UMSOM Center for Advanced Research Training and Innovation, who co-organized the DPSG meeting. “They’re taking the hypothesis and dissecting it by asking, for instance, it is possible that transgenerational obesity may align with the Barker hypothesis? Is it possible that it involves epigenetics regulation? Could we find biomarkers?”
The need for a better understanding of the fetal origins framework — and its subsequent transgenerational impact — is urgent. From 2000 to 2018, the prevalence of childhood obesity increased from 14.7% to 19.2% (a 31% increase) and the prevalence of severe childhood obesity rose from 3.9% to 6.1% (a 56% increase), according to data from the U.S. National Health and Nutrition Examination Survey (Obes Facts. 2022;15[4]:560-9).
Children aged 2-5 years have had an especially sharp increase in obesity (Pediatrics 2018;141[3]:e20173459), Christine Wey Hockett, PhD, of the University of South Dakota School of Medicine, said at the DPSG meeting (Figure 1). 
Also notable, she said, is that one-quarter of today’s pediatric diabetes cases are type 2 diabetes, which “is significant as there is a higher prevalence of early complications and comorbidities in youth with type 2 diabetes compared to type 1 diabetes.”
Moreover, recent projections estimate that 57% of today’s children will be obese at 35 years of age (N Engl J Med. 2017;377[22]:2145-53) and that 45% will have diabetes or prediabetes by 2030 (Popul Health Manag. 2017;20[1]:6-12), said Dr. Hockett, assistant professor in the university’s department of pediatrics. An investigator of the Exploring Perinatal Outcomes Among Children (EPOCH) study, which looked at gestational diabetes (GDM) and offspring cardiometabolic risks, she said more chronic disease “at increasingly younger ages [points toward] prebirth influences.”
She noted that there are critical periods postnatally — such as infancy and puberty — that can “impact or further shift the trajectory of chronic disease.” The developmental origins theory posits that life events and biological and environmental processes during the lifespan can modify the effects of intrauterine exposures.
The transgenerational implications “are clear,” she said. “As the number of reproductive-aged individuals with chronic diseases rises, the number of exposed offspring also rises ... It leads to a vicious cycle.”
Deeper Dives Into Associations, Potential Mechanisms
The EPOCH prospective cohort study with which Dr. Hockett was involved gave her a front-seat view of the transgenerational adverse effects of in utero exposure to hyperglycemia. The study recruited ethnically diverse maternal/child dyads from the Kaiser Permanente of Colorado perinatal database from 1992 to 2002 and assessed 418 offspring at two points — a mean age of 10.5 years and 16.5 years — for fasting blood glucose, adiposity, and diet and physical activity. The second visit also involved an oral glucose tolerance test.
The 77 offspring who had been exposed in utero to GDM had a homeostatic model assessment of insulin resistance (HOMA-IR) that was 18% higher, a 19% lower Matsuda index, and a 9% greater HOMA of β-cell function (HOMA-β) than the 341 offspring whose mothers did not have diabetes. Each 5-kg/m2 increase in prepregnancy body mass index predicted increased insulin resistance, but there was no combined effect of both maternal obesity and diabetes in utero.
Exposed offspring had a higher BMI and increased adiposity, but when BMI was controlled for in the analysis of metabolic outcomes, maternal diabetes was still associated with 12% higher HOMA-IR and a 17% lower Matsuda index. “So [the metabolic outcomes] are a direct effect of maternal diabetes,” Dr. Hockett said at the DPSG meeting, noting the fetal overnutrition hypothesis in which maternal glucose, but not maternal insulin, freely passes through the placenta, promoting growth and adiposity in the fetus.
[The EPOCH results on metabolic outcomes and offspring adiposity were published in 2017 and 2019, respectively (Diabet Med. 2017;34:1392-9; Diabetologia. 2019;62:2017-24). In 2020, EPOCH researchers reported sex-specific effects on cardiovascular outcomes, with GDM exposure associated with higher total and LDL cholesterol in girls and higher systolic blood pressure in boys (Pediatr Obes. 2020;15[5]:e12611).]
Now, a new longitudinal cohort study underway in Phoenix, is taking a deeper dive, trying to pinpoint what exactly influences childhood obesity and metabolic risk by following Hispanic and American Indian maternal/child dyads from pregnancy until 18 years postpartum. Researchers are looking not only at associations between maternal risk factors (pregnancy BMI, gestational weight gain, and diabetes in pregnancy) and offspring BMI, adiposity, and growth patterns, but also how various factors during pregnancy — clinical, genetic, lifestyle, biochemical — ”may mediate the associations,” said lead investigator Madhumita Sinha, MD.
“We need a better understanding at the molecular level of the biological processes that lead to obesity in children and that cause metabolic dysfunction,” said Dr. Sinha, who heads the Diabetes Epidemiology and Clinical Research Section of the of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) branch in Phoenix.
The populations being enrolled in the ETCHED study (for Early Tracking of Childhood Health Determinants) are at especially high risk of childhood obesity and metabolic dysfunction. Research conducted decades ago by the NIDDK in Phoenix showed that approximately 50% of Pima Indian children from diabetic pregnancies develop type 2 diabetes by age 25 (N Engl J Med. 1983;308:242-5). Years later, to tease out possible genetic factors, researchers compared siblings born before and after their mother was found to have type 2 diabetes, and found significantly higher rates of diabetes in those born after the mother’s diagnosis, affirming the role of in utero toxicity (Diabetes 2000;49:2208-11).
In the new study, the researchers will look at adipokines and inflammatory biomarkers in the mothers and offspring in addition to traditional anthropometric and glycemic measures. They’ll analyze placental tissue, breast milk, and the gut microbiome longitudinally, and they’ll lean heavily on genomics/epigenomics, proteomics, and metabolomics. “There’s potential,” Dr. Sinha said, “to develop a more accurate predictive and prognostic model of childhood obesity.”
The researchers also will study the role of family, socioeconomics, and environmental factors in influencing child growth patterns and they’ll look at neurodevelopment in infancy and childhood. As of October 2023, almost 80 pregnant women, most with obesity and almost one-third with type 2 diabetes, had enrolled in the study. Over the next several years, the study aims to enroll 750 dyads.
The Timing of In Utero Exposure
Shelley Ehrlich, MD, ScD, MPH, of the University of Cincinnati and Cincinnati Children’s Hospital Medical Center, is aiming, meanwhile, to learn how the timing of in utero exposure to hyperglycemia predicts specific metabolic and cardiovascular morbidities in the adult offspring of diabetic mothers.
“While we know that exposure to maternal diabetes, regardless of type, increases the risk of obesity, insulin resistance, diabetes, renal compromise, and cardiovascular disease in the offspring, there is little known about the level and timing of hyperglycemic exposure during fetal development that triggers these adverse outcomes,” said Dr. Ehrlich. A goal, she said, is to identify gestational profiles that predict phenotypes of offspring at risk for morbidity in later life.
She and other investigators with the TEAM (Transgenerational Effect on Adult Morbidity) study have recruited over 170 offspring of mothers who participated in the Diabetes in Pregnancy Program Project Grant (PPG) at the University of Cincinnati Medical Center from 1978 to 1995 — a landmark study that demonstrated the effect of strict glucose control in reducing major congenital malformations.
The women in the PPG study had frequent glucose monitoring (up to 6-8 times a day) throughout their pregnancies, and now, their recruited offspring, who are up to 43 years of age, are being assessed for obesity, diabetes/metabolic health, cardiovascular disease/cardiac and peripheral vascular structure and function, and other outcomes including those that may be amenable to secondary prevention (J Diabetes Res. Nov 1;2021:6590431).
Preliminary findings from over 170 offspring recruited between 2017 and 2022 suggest that in utero exposure to dysglycemia (as measured by standard deviations of glycohemoglobin) in the third trimester appears to increase the risk of morbid obesity in adulthood, while exposure to dysglycemia in the first trimester increases the risk of impaired glucose tolerance. The risk of B-cell dysfunction, meanwhile, appears to be linked to dysglycemia in the first and third trimesters — particularly the first — Dr. Ehrlich reported.
Cognitive outcomes in offspring have also been assessed and here it appears that dysglycemia in the third trimester is linked to worse scores on the Wechsler Abbreviated Scale of Intelligence (WASI-II), said Katherine Bowers, PhD, MPH, a TEAM study coinvestigator, also of Cincinnati Children’s Hospital Medical Center.
“We’ve already observed [an association between] diabetes in pregnancy and cognition in early childhood and through adolescence, but [the question has been] does this association persist into adulthood?” she said.
Preliminary analyses of 104 offspring show no statistically significant associations between maternal dysglycemia in the first or second trimesters and offspring cognition, but “consistent inverse associations between maternal glycohemoglobin in the third trimester across two [WASI-II] subscales and composite measures of cognition,” Dr. Bowers said.
Their analysis adjusted for a variety of factors, including maternal age, prepregnancy and first trimester BMI, race, family history of diabetes, and diabetes severity/macrovascular complications.
Back In The Laboratory
At the other end of the research spectrum, basic research scientists are also investigating the mechanisms and sequelae of in utero hyperglycemia and other injuries, including congenital malformations, placental adaptive responses and fetal programming. Researchers are asking, for instance, what does placental metabolic reprogramming entail? What role do placental extracellular vesicles play in GDM? Can we alter the in utero environment and thus improve the short and long-term fetal/infant outcomes?
Animal research done at the UMSOM Center for Birth Defects Research, led by Dr. Reece and Peixin Yang, PhD, suggests that “a good portion of in utero injury is due to epigenetics,” Dr. Reece said in the interview. “We’ve shown that under conditions of hyperglycemia, for example, genetic regulation and genetic function can be altered.”
Through in vivo research, they have also shown that antioxidants or membrane stabilizers such as arachidonic acid or myo-inositol, or experimental inhibitors to certain pro-apoptotic intermediates, can individually or collectively result in reduced malformations. “It is highly likely that understanding the biological impact of various altered in utero environments, and then modifying or reversing those environments, will result in short and long-term outcome improvements similar to those shown with congenital malformations,” Dr. Reece said.
FAIRFAX, VIRGINIA — Nearly 30 years ago, in a 1995 paper, the British physician-epidemiologist David Barker, MD, PhD, wrote about his fetal origins hypothesis — the idea that programs to address fetal undernutrition and low birth weight produced later coronary heart disease (BMJ 1995;311:171-4).
His hypothesis and subsequent research led to the concept of adult diseases of fetal origins, which today extends beyond low birth weight and implicates the in utero environment as a significant determinant of risk for adverse childhood and adult metabolic outcomes and for major chronic diseases, including diabetes and obesity. Studies have shown that the offspring of pregnant mothers with diabetes have a higher risk of developing obesity and diabetes themselves.
“It’s a whole discipline [of research],” E. Albert Reece, MD, PhD, MBA, of the University of Maryland School of Medicine (UMSOM), said in an interview. “But what we’ve never quite understood is the ‘how’ and ‘why’? What are the mechanisms driving the fetal origins of such adverse outcomes in offspring?
At the biennial meeting of the Diabetes in Pregnancy Study Group of North America (DPSG), investigators described studies underway that are digging deeper into the associations between the intrauterine milieu and longer-term offspring health — and that are searching for biological and molecular processes that may be involved.
The studies are like “branches of the Barker hypothesis,” said Dr. Reece, former dean of UMSOM and current director of the UMSOM Center for Advanced Research Training and Innovation, who co-organized the DPSG meeting. “They’re taking the hypothesis and dissecting it by asking, for instance, it is possible that transgenerational obesity may align with the Barker hypothesis? Is it possible that it involves epigenetics regulation? Could we find biomarkers?”
The need for a better understanding of the fetal origins framework — and its subsequent transgenerational impact — is urgent. From 2000 to 2018, the prevalence of childhood obesity increased from 14.7% to 19.2% (a 31% increase) and the prevalence of severe childhood obesity rose from 3.9% to 6.1% (a 56% increase), according to data from the U.S. National Health and Nutrition Examination Survey (Obes Facts. 2022;15[4]:560-9).
Children aged 2-5 years have had an especially sharp increase in obesity (Pediatrics 2018;141[3]:e20173459), Christine Wey Hockett, PhD, of the University of South Dakota School of Medicine, said at the DPSG meeting (Figure 1).
Also notable, she said, is that one-quarter of today’s pediatric diabetes cases are type 2 diabetes, which “is significant as there is a higher prevalence of early complications and comorbidities in youth with type 2 diabetes compared to type 1 diabetes.”
Moreover, recent projections estimate that 57% of today’s children will be obese at 35 years of age (N Engl J Med. 2017;377[22]:2145-53) and that 45% will have diabetes or prediabetes by 2030 (Popul Health Manag. 2017;20[1]:6-12), said Dr. Hockett, assistant professor in the university’s department of pediatrics. An investigator of the Exploring Perinatal Outcomes Among Children (EPOCH) study, which looked at gestational diabetes (GDM) and offspring cardiometabolic risks, she said more chronic disease “at increasingly younger ages [points toward] prebirth influences.”
She noted that there are critical periods postnatally — such as infancy and puberty — that can “impact or further shift the trajectory of chronic disease.” The developmental origins theory posits that life events and biological and environmental processes during the lifespan can modify the effects of intrauterine exposures.
The transgenerational implications “are clear,” she said. “As the number of reproductive-aged individuals with chronic diseases rises, the number of exposed offspring also rises ... It leads to a vicious cycle.”
Deeper Dives Into Associations, Potential Mechanisms
The EPOCH prospective cohort study with which Dr. Hockett was involved gave her a front-seat view of the transgenerational adverse effects of in utero exposure to hyperglycemia. The study recruited ethnically diverse maternal/child dyads from the Kaiser Permanente of Colorado perinatal database from 1992 to 2002 and assessed 418 offspring at two points — a mean age of 10.5 years and 16.5 years — for fasting blood glucose, adiposity, and diet and physical activity. The second visit also involved an oral glucose tolerance test.
The 77 offspring who had been exposed in utero to GDM had a homeostatic model assessment of insulin resistance (HOMA-IR) that was 18% higher, a 19% lower Matsuda index, and a 9% greater HOMA of β-cell function (HOMA-β) than the 341 offspring whose mothers did not have diabetes. Each 5-kg/m2 increase in prepregnancy body mass index predicted increased insulin resistance, but there was no combined effect of both maternal obesity and diabetes in utero.
Exposed offspring had a higher BMI and increased adiposity, but when BMI was controlled for in the analysis of metabolic outcomes, maternal diabetes was still associated with 12% higher HOMA-IR and a 17% lower Matsuda index. “So [the metabolic outcomes] are a direct effect of maternal diabetes,” Dr. Hockett said at the DPSG meeting, noting the fetal overnutrition hypothesis in which maternal glucose, but not maternal insulin, freely passes through the placenta, promoting growth and adiposity in the fetus.
[The EPOCH results on metabolic outcomes and offspring adiposity were published in 2017 and 2019, respectively (Diabet Med. 2017;34:1392-9; Diabetologia. 2019;62:2017-24). In 2020, EPOCH researchers reported sex-specific effects on cardiovascular outcomes, with GDM exposure associated with higher total and LDL cholesterol in girls and higher systolic blood pressure in boys (Pediatr Obes. 2020;15[5]:e12611).]
Now, a new longitudinal cohort study underway in Phoenix, is taking a deeper dive, trying to pinpoint what exactly influences childhood obesity and metabolic risk by following Hispanic and American Indian maternal/child dyads from pregnancy until 18 years postpartum. Researchers are looking not only at associations between maternal risk factors (pregnancy BMI, gestational weight gain, and diabetes in pregnancy) and offspring BMI, adiposity, and growth patterns, but also how various factors during pregnancy — clinical, genetic, lifestyle, biochemical — ”may mediate the associations,” said lead investigator Madhumita Sinha, MD.
“We need a better understanding at the molecular level of the biological processes that lead to obesity in children and that cause metabolic dysfunction,” said Dr. Sinha, who heads the Diabetes Epidemiology and Clinical Research Section of the of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) branch in Phoenix.
The populations being enrolled in the ETCHED study (for Early Tracking of Childhood Health Determinants) are at especially high risk of childhood obesity and metabolic dysfunction. Research conducted decades ago by the NIDDK in Phoenix showed that approximately 50% of Pima Indian children from diabetic pregnancies develop type 2 diabetes by age 25 (N Engl J Med. 1983;308:242-5). Years later, to tease out possible genetic factors, researchers compared siblings born before and after their mother was found to have type 2 diabetes, and found significantly higher rates of diabetes in those born after the mother’s diagnosis, affirming the role of in utero toxicity (Diabetes 2000;49:2208-11).
In the new study, the researchers will look at adipokines and inflammatory biomarkers in the mothers and offspring in addition to traditional anthropometric and glycemic measures. They’ll analyze placental tissue, breast milk, and the gut microbiome longitudinally, and they’ll lean heavily on genomics/epigenomics, proteomics, and metabolomics. “There’s potential,” Dr. Sinha said, “to develop a more accurate predictive and prognostic model of childhood obesity.”
The researchers also will study the role of family, socioeconomics, and environmental factors in influencing child growth patterns and they’ll look at neurodevelopment in infancy and childhood. As of October 2023, almost 80 pregnant women, most with obesity and almost one-third with type 2 diabetes, had enrolled in the study. Over the next several years, the study aims to enroll 750 dyads.
The Timing of In Utero Exposure
Shelley Ehrlich, MD, ScD, MPH, of the University of Cincinnati and Cincinnati Children’s Hospital Medical Center, is aiming, meanwhile, to learn how the timing of in utero exposure to hyperglycemia predicts specific metabolic and cardiovascular morbidities in the adult offspring of diabetic mothers.
“While we know that exposure to maternal diabetes, regardless of type, increases the risk of obesity, insulin resistance, diabetes, renal compromise, and cardiovascular disease in the offspring, there is little known about the level and timing of hyperglycemic exposure during fetal development that triggers these adverse outcomes,” said Dr. Ehrlich. A goal, she said, is to identify gestational profiles that predict phenotypes of offspring at risk for morbidity in later life.
She and other investigators with the TEAM (Transgenerational Effect on Adult Morbidity) study have recruited over 170 offspring of mothers who participated in the Diabetes in Pregnancy Program Project Grant (PPG) at the University of Cincinnati Medical Center from 1978 to 1995 — a landmark study that demonstrated the effect of strict glucose control in reducing major congenital malformations.
The women in the PPG study had frequent glucose monitoring (up to 6-8 times a day) throughout their pregnancies, and now, their recruited offspring, who are up to 43 years of age, are being assessed for obesity, diabetes/metabolic health, cardiovascular disease/cardiac and peripheral vascular structure and function, and other outcomes including those that may be amenable to secondary prevention (J Diabetes Res. Nov 1;2021:6590431).
Preliminary findings from over 170 offspring recruited between 2017 and 2022 suggest that in utero exposure to dysglycemia (as measured by standard deviations of glycohemoglobin) in the third trimester appears to increase the risk of morbid obesity in adulthood, while exposure to dysglycemia in the first trimester increases the risk of impaired glucose tolerance. The risk of B-cell dysfunction, meanwhile, appears to be linked to dysglycemia in the first and third trimesters — particularly the first — Dr. Ehrlich reported.
Cognitive outcomes in offspring have also been assessed and here it appears that dysglycemia in the third trimester is linked to worse scores on the Wechsler Abbreviated Scale of Intelligence (WASI-II), said Katherine Bowers, PhD, MPH, a TEAM study coinvestigator, also of Cincinnati Children’s Hospital Medical Center.
“We’ve already observed [an association between] diabetes in pregnancy and cognition in early childhood and through adolescence, but [the question has been] does this association persist into adulthood?” she said.
Preliminary analyses of 104 offspring show no statistically significant associations between maternal dysglycemia in the first or second trimesters and offspring cognition, but “consistent inverse associations between maternal glycohemoglobin in the third trimester across two [WASI-II] subscales and composite measures of cognition,” Dr. Bowers said.
Their analysis adjusted for a variety of factors, including maternal age, prepregnancy and first trimester BMI, race, family history of diabetes, and diabetes severity/macrovascular complications.
Back In The Laboratory
At the other end of the research spectrum, basic research scientists are also investigating the mechanisms and sequelae of in utero hyperglycemia and other injuries, including congenital malformations, placental adaptive responses and fetal programming. Researchers are asking, for instance, what does placental metabolic reprogramming entail? What role do placental extracellular vesicles play in GDM? Can we alter the in utero environment and thus improve the short and long-term fetal/infant outcomes?
Animal research done at the UMSOM Center for Birth Defects Research, led by Dr. Reece and Peixin Yang, PhD, suggests that “a good portion of in utero injury is due to epigenetics,” Dr. Reece said in the interview. “We’ve shown that under conditions of hyperglycemia, for example, genetic regulation and genetic function can be altered.”
Through in vivo research, they have also shown that antioxidants or membrane stabilizers such as arachidonic acid or myo-inositol, or experimental inhibitors to certain pro-apoptotic intermediates, can individually or collectively result in reduced malformations. “It is highly likely that understanding the biological impact of various altered in utero environments, and then modifying or reversing those environments, will result in short and long-term outcome improvements similar to those shown with congenital malformations,” Dr. Reece said.
FAIRFAX, VIRGINIA — Nearly 30 years ago, in a 1995 paper, the British physician-epidemiologist David Barker, MD, PhD, wrote about his fetal origins hypothesis — the idea that programs to address fetal undernutrition and low birth weight produced later coronary heart disease (BMJ 1995;311:171-4).
His hypothesis and subsequent research led to the concept of adult diseases of fetal origins, which today extends beyond low birth weight and implicates the in utero environment as a significant determinant of risk for adverse childhood and adult metabolic outcomes and for major chronic diseases, including diabetes and obesity. Studies have shown that the offspring of pregnant mothers with diabetes have a higher risk of developing obesity and diabetes themselves.
“It’s a whole discipline [of research],” E. Albert Reece, MD, PhD, MBA, of the University of Maryland School of Medicine (UMSOM), said in an interview. “But what we’ve never quite understood is the ‘how’ and ‘why’? What are the mechanisms driving the fetal origins of such adverse outcomes in offspring?
At the biennial meeting of the Diabetes in Pregnancy Study Group of North America (DPSG), investigators described studies underway that are digging deeper into the associations between the intrauterine milieu and longer-term offspring health — and that are searching for biological and molecular processes that may be involved.
The studies are like “branches of the Barker hypothesis,” said Dr. Reece, former dean of UMSOM and current director of the UMSOM Center for Advanced Research Training and Innovation, who co-organized the DPSG meeting. “They’re taking the hypothesis and dissecting it by asking, for instance, it is possible that transgenerational obesity may align with the Barker hypothesis? Is it possible that it involves epigenetics regulation? Could we find biomarkers?”
The need for a better understanding of the fetal origins framework — and its subsequent transgenerational impact — is urgent. From 2000 to 2018, the prevalence of childhood obesity increased from 14.7% to 19.2% (a 31% increase) and the prevalence of severe childhood obesity rose from 3.9% to 6.1% (a 56% increase), according to data from the U.S. National Health and Nutrition Examination Survey (Obes Facts. 2022;15[4]:560-9).
Children aged 2-5 years have had an especially sharp increase in obesity (Pediatrics 2018;141[3]:e20173459), Christine Wey Hockett, PhD, of the University of South Dakota School of Medicine, said at the DPSG meeting (Figure 1).
Also notable, she said, is that one-quarter of today’s pediatric diabetes cases are type 2 diabetes, which “is significant as there is a higher prevalence of early complications and comorbidities in youth with type 2 diabetes compared to type 1 diabetes.”
Moreover, recent projections estimate that 57% of today’s children will be obese at 35 years of age (N Engl J Med. 2017;377[22]:2145-53) and that 45% will have diabetes or prediabetes by 2030 (Popul Health Manag. 2017;20[1]:6-12), said Dr. Hockett, assistant professor in the university’s department of pediatrics. An investigator of the Exploring Perinatal Outcomes Among Children (EPOCH) study, which looked at gestational diabetes (GDM) and offspring cardiometabolic risks, she said more chronic disease “at increasingly younger ages [points toward] prebirth influences.”
She noted that there are critical periods postnatally — such as infancy and puberty — that can “impact or further shift the trajectory of chronic disease.” The developmental origins theory posits that life events and biological and environmental processes during the lifespan can modify the effects of intrauterine exposures.
The transgenerational implications “are clear,” she said. “As the number of reproductive-aged individuals with chronic diseases rises, the number of exposed offspring also rises ... It leads to a vicious cycle.”
Deeper Dives Into Associations, Potential Mechanisms
The EPOCH prospective cohort study with which Dr. Hockett was involved gave her a front-seat view of the transgenerational adverse effects of in utero exposure to hyperglycemia. The study recruited ethnically diverse maternal/child dyads from the Kaiser Permanente of Colorado perinatal database from 1992 to 2002 and assessed 418 offspring at two points — a mean age of 10.5 years and 16.5 years — for fasting blood glucose, adiposity, and diet and physical activity. The second visit also involved an oral glucose tolerance test.
The 77 offspring who had been exposed in utero to GDM had a homeostatic model assessment of insulin resistance (HOMA-IR) that was 18% higher, a 19% lower Matsuda index, and a 9% greater HOMA of β-cell function (HOMA-β) than the 341 offspring whose mothers did not have diabetes. Each 5-kg/m2 increase in prepregnancy body mass index predicted increased insulin resistance, but there was no combined effect of both maternal obesity and diabetes in utero.
Exposed offspring had a higher BMI and increased adiposity, but when BMI was controlled for in the analysis of metabolic outcomes, maternal diabetes was still associated with 12% higher HOMA-IR and a 17% lower Matsuda index. “So [the metabolic outcomes] are a direct effect of maternal diabetes,” Dr. Hockett said at the DPSG meeting, noting the fetal overnutrition hypothesis in which maternal glucose, but not maternal insulin, freely passes through the placenta, promoting growth and adiposity in the fetus.
[The EPOCH results on metabolic outcomes and offspring adiposity were published in 2017 and 2019, respectively (Diabet Med. 2017;34:1392-9; Diabetologia. 2019;62:2017-24). In 2020, EPOCH researchers reported sex-specific effects on cardiovascular outcomes, with GDM exposure associated with higher total and LDL cholesterol in girls and higher systolic blood pressure in boys (Pediatr Obes. 2020;15[5]:e12611).]
Now, a new longitudinal cohort study underway in Phoenix, is taking a deeper dive, trying to pinpoint what exactly influences childhood obesity and metabolic risk by following Hispanic and American Indian maternal/child dyads from pregnancy until 18 years postpartum. Researchers are looking not only at associations between maternal risk factors (pregnancy BMI, gestational weight gain, and diabetes in pregnancy) and offspring BMI, adiposity, and growth patterns, but also how various factors during pregnancy — clinical, genetic, lifestyle, biochemical — ”may mediate the associations,” said lead investigator Madhumita Sinha, MD.
“We need a better understanding at the molecular level of the biological processes that lead to obesity in children and that cause metabolic dysfunction,” said Dr. Sinha, who heads the Diabetes Epidemiology and Clinical Research Section of the of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) branch in Phoenix.
The populations being enrolled in the ETCHED study (for Early Tracking of Childhood Health Determinants) are at especially high risk of childhood obesity and metabolic dysfunction. Research conducted decades ago by the NIDDK in Phoenix showed that approximately 50% of Pima Indian children from diabetic pregnancies develop type 2 diabetes by age 25 (N Engl J Med. 1983;308:242-5). Years later, to tease out possible genetic factors, researchers compared siblings born before and after their mother was found to have type 2 diabetes, and found significantly higher rates of diabetes in those born after the mother’s diagnosis, affirming the role of in utero toxicity (Diabetes 2000;49:2208-11).
In the new study, the researchers will look at adipokines and inflammatory biomarkers in the mothers and offspring in addition to traditional anthropometric and glycemic measures. They’ll analyze placental tissue, breast milk, and the gut microbiome longitudinally, and they’ll lean heavily on genomics/epigenomics, proteomics, and metabolomics. “There’s potential,” Dr. Sinha said, “to develop a more accurate predictive and prognostic model of childhood obesity.”
The researchers also will study the role of family, socioeconomics, and environmental factors in influencing child growth patterns and they’ll look at neurodevelopment in infancy and childhood. As of October 2023, almost 80 pregnant women, most with obesity and almost one-third with type 2 diabetes, had enrolled in the study. Over the next several years, the study aims to enroll 750 dyads.
The Timing of In Utero Exposure
Shelley Ehrlich, MD, ScD, MPH, of the University of Cincinnati and Cincinnati Children’s Hospital Medical Center, is aiming, meanwhile, to learn how the timing of in utero exposure to hyperglycemia predicts specific metabolic and cardiovascular morbidities in the adult offspring of diabetic mothers.
“While we know that exposure to maternal diabetes, regardless of type, increases the risk of obesity, insulin resistance, diabetes, renal compromise, and cardiovascular disease in the offspring, there is little known about the level and timing of hyperglycemic exposure during fetal development that triggers these adverse outcomes,” said Dr. Ehrlich. A goal, she said, is to identify gestational profiles that predict phenotypes of offspring at risk for morbidity in later life.
She and other investigators with the TEAM (Transgenerational Effect on Adult Morbidity) study have recruited over 170 offspring of mothers who participated in the Diabetes in Pregnancy Program Project Grant (PPG) at the University of Cincinnati Medical Center from 1978 to 1995 — a landmark study that demonstrated the effect of strict glucose control in reducing major congenital malformations.
The women in the PPG study had frequent glucose monitoring (up to 6-8 times a day) throughout their pregnancies, and now, their recruited offspring, who are up to 43 years of age, are being assessed for obesity, diabetes/metabolic health, cardiovascular disease/cardiac and peripheral vascular structure and function, and other outcomes including those that may be amenable to secondary prevention (J Diabetes Res. Nov 1;2021:6590431).
Preliminary findings from over 170 offspring recruited between 2017 and 2022 suggest that in utero exposure to dysglycemia (as measured by standard deviations of glycohemoglobin) in the third trimester appears to increase the risk of morbid obesity in adulthood, while exposure to dysglycemia in the first trimester increases the risk of impaired glucose tolerance. The risk of B-cell dysfunction, meanwhile, appears to be linked to dysglycemia in the first and third trimesters — particularly the first — Dr. Ehrlich reported.
Cognitive outcomes in offspring have also been assessed and here it appears that dysglycemia in the third trimester is linked to worse scores on the Wechsler Abbreviated Scale of Intelligence (WASI-II), said Katherine Bowers, PhD, MPH, a TEAM study coinvestigator, also of Cincinnati Children’s Hospital Medical Center.
“We’ve already observed [an association between] diabetes in pregnancy and cognition in early childhood and through adolescence, but [the question has been] does this association persist into adulthood?” she said.
Preliminary analyses of 104 offspring show no statistically significant associations between maternal dysglycemia in the first or second trimesters and offspring cognition, but “consistent inverse associations between maternal glycohemoglobin in the third trimester across two [WASI-II] subscales and composite measures of cognition,” Dr. Bowers said.
Their analysis adjusted for a variety of factors, including maternal age, prepregnancy and first trimester BMI, race, family history of diabetes, and diabetes severity/macrovascular complications.
Back In The Laboratory
At the other end of the research spectrum, basic research scientists are also investigating the mechanisms and sequelae of in utero hyperglycemia and other injuries, including congenital malformations, placental adaptive responses and fetal programming. Researchers are asking, for instance, what does placental metabolic reprogramming entail? What role do placental extracellular vesicles play in GDM? Can we alter the in utero environment and thus improve the short and long-term fetal/infant outcomes?
Animal research done at the UMSOM Center for Birth Defects Research, led by Dr. Reece and Peixin Yang, PhD, suggests that “a good portion of in utero injury is due to epigenetics,” Dr. Reece said in the interview. “We’ve shown that under conditions of hyperglycemia, for example, genetic regulation and genetic function can be altered.”
Through in vivo research, they have also shown that antioxidants or membrane stabilizers such as arachidonic acid or myo-inositol, or experimental inhibitors to certain pro-apoptotic intermediates, can individually or collectively result in reduced malformations. “It is highly likely that understanding the biological impact of various altered in utero environments, and then modifying or reversing those environments, will result in short and long-term outcome improvements similar to those shown with congenital malformations,” Dr. Reece said.
FROM DPSG-NA 2023