Examining a Developmental Approach to Childhood Obesity The Fetal and Early Childhood Years: Workshop Summary (2015) / Chapter Skim
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5 Real-World Application
5 Real-World Application
Pages 91-120
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From page 91... ...
According to Aryeh Stein of Emory University, the Dutch Hunger inter W of 1944–1945, which Karen Lillycrop had briefly mentioned in her earlier presentation, has long been recognized by researchers as a useful period for studying the effects of short-term hunger on subsequent generations. Stein summarized evidence from those and other studies on "real-world" human prenatal exposure to famine and its effects on obesity-related outcomes.
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From page 92... ...
For example, evidence suggests that maternal poor nutrition during pregnancy combined with rapid infant catch-up growth leads to increased metabolic dysfunction in offspring. A potential clinical application of this knowledge is the promotion of appetite regulation during infancy.
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From page 93... ...
Individuals were also grouped according to the timing of exposure during gestation. The authors reported that individuals exposed during early and middle gestation had an increased prevalence of obesity at age 19 compared to individuals born in unaffected areas and that individuals exposed during very late gestation had a lower prevalence of obesity compared to individuals born in unaffected areas (i.e., obesity as defined 1 This section summarizes information and opinions presented by Aryeh Stein, M.P.H., Ph.D., Emory University, Atlanta, Georgia.
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From page 94... ...
In addition to the Dutch Hunger Winter, the Leningrad siege of 1941– 1944 has also been studied for its association with adult body weight. Stanner et al.
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From page 95... ...
Both areas suffered famines, but because mass shipments of food were sent from rural to urban areas, rural areas suffered a more severe famine. The researchers reported that individuals born before the famine had higher BMIs than individuals born after the famine, but that individuals born during the famine had lower BMIs than individuals born after the famine.
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From page 96... ...
Summary of the Evidence In summary, Stein found three relevant studies of the Dutch Hunger Winter. All three studies suggested that at least one group of individuals exposed to the famine in utero showed an increased prevalence of at least one measure of overweight later in life, with early gestation tending to have stronger associations than later gestation and with stronger associations observed in women than in men (when the researchers were able to analyze both sexes)
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From page 97... ...
Nor have any of the famine studies been able to separate the effects of food shortages from the effects of all the other wartime stressors, such as the particularly cold temperatures of the Dutch Hunger Winter. It is impossible to know how many of the observed effects were due to the famine versus the cold temperature.
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From page 98... ...
Epigenetic programming also resonates publicly, Richardson continued, because it raises philosophically riveting questions of the possibility that 2 Thissection summarizes information and opinions presented by Sarah Richardson, M.A., Ph.D., Harvard University, Boston, Massachusetts.
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From page 99... ...
Epigenetic studies of maternal effects, given this backdrop of history, raise vital social, ethical, and philosophical questions for Richardson and others. Is there a potential for this new research to heighten public health surveillance of and restrictions on pregnant women and mothers through a molecular policing of their behavior?
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From page 100... ...
According to Wells, Richardson explained, the maternal body serves as a transducing medium for health inequalities from one generation to another. In Wells's model, what he calls "maternal capital," including public health policies, education, and health care, is corporealized in the maternal–fetal relation, Richardson explained.
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From page 101... ...
. The Maternal Body as an Epigenetic Vector Richardson has argued in some of her writing on maternal fetal epigenetics that in scientific research the maternal body emerges as an epigenetic vector -- an intensified space for the introduction of epigenetic perturbations in development.
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From page 102... ...
Third, while the target of intervention is the maternal body, the desired outcome of epigenetics-driven health interventions is usually improved fetal health. Researchers, of course, do hope that a collateral effect of their policies will be to enhance resources for pregnant women.
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From page 103... ...
Conclusion In wrapping up, Richardson reiterated that epigenetic research on maternal effects advances a model of human inheritance and development in which the wider social and physical environment can be seen as heritable and as a determinant of future biomedical outcomes via discreet bio hemical modifi c cations introduced by the amplifying vector of the maternal body. She stated that while the hope is that this literature would move the field away from forms of deterministic explanations, in fact the language strongly resembles that of genetic determinism.
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From page 104... ...
Examples of DOHaD health policies are Massachusetts's regulation of child care centers requiring each child to participate in at least 60 minutes of physical activity daily and baby-friendly hospital initiatives to promote breastfeeding initiation, duration, and exclusivity, or to screen and provide treatment recommendations for gestational diabetes. Gillman explained that DOHaD health policies also include government policies, such as cigarette tax policies that reduce smoking both outside of and during pregnancy, and mixtures of government and health care policies such as the IOM guidelines for gestational weight gain, which could be transmitted either through health care or outside of health care.
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From page 105... ...
In particular, he suggested that animal studies follow epidemiology's lead in addressing pre-pregnancy obesity, gestational weight gain, low-carbohydrate and high-protein diets, glycemic index or load, vitamin D, and smoking. In his opinion, it would be great to have all of these translated into animal models.
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From page 106... ...
He noted that his list of innovative study designs or analyses was very similar to Caroline Relton's list (see Chapter 3 for a summary of Relton's presentation) : judicious multivariable analysis, sibling-pair design, cohorts with different confounding structures, comparing maternal versus paternal effects, long-term follow-up of randomized controlled trials, Mendelian randomization, the use of biomarkers, and quasi-experimental studies (which Gillman noted are not really cohort studies, but usually repeated cross-sectional studies)
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From page 107... ...
That is, if certain pre- and perinatal factors are related to epigenetic markers that themselves are related to certain outcomes, the question for Gillman then becomes, "How can we prevent those pre- and perinatal risk factors in the beginning? " In a recently published editorial on primordial prevention of cardiovascular disease, Gillman wrote about optimizing the socio-behavioral milieu starting with conception, or even preconception, as a way to avoid exposures known to be related to offspring obesity, such as maternal obesity, excess gestational weight gain, gestational diabetes, and smoking (Gillman, 2015)
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From page 108... ...
Associations between gestational weight gain and different outcomes vary. For example, the association with preterm delivery is U-shaped, whereas the association with small for gestational age is indirect and the associations with large for gestational age, postpartum weight retention, and child obesity are all direct.
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From page 109... ...
But for policy translation, Gillman encouraged researchers to move beyond efficacy and focus more on implementation. He listed some prevention interventions that the Harvard Pilgrim Health Care Institute's Obesity Prevention Program has been involved with, many of which are cluster randomized controlled trials.
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From page 110... ...
The first was a Project Viva time-series analysis of fish intake among pregnant women following warnings to eat less fish that was known to have high levels of mercury (Oken et al., 2003)
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From page 111... ...
. THEORY TO CLINICAL PRACTICE4 If scientists know the effects of what happens in utero and early in life, such as that excess gestational weight gain and rapid infant weight gain in the first 6 months of life place a child at greater risk for insulin resistance, hypertension, and obesity, then for Shari Barkin of the Vanderbilt University Medical Center, the key question is, how can clinicians apply that knowledge in their practices?
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From page 112... ...
. With all of this variability as a caveat, Barkin highlighted two pregnancy interventions focused on physical activity and nutrition education during pregnancy.
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From page 113... ...
"Stay tuned for more details," she said. "We are in the evolving stages of examining evidence related to this type of clinical application." In addition to the potential clinical applications of scientific evidence related to physical activity and nutrition during pregnancy, Barkin discussed potential applications of what is known about maternal excess gestational weight and its interaction with pre-pregnancy weight to alter early infant growth trajectories.
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From page 114... ...
In a study aimed at understanding how excess gestational weight gain interacts with pregnancy weight to alter early infant growth trajectories, Barkin and colleagues used linked electronic medical record data for about 500 mother–child pairs and objective measurements of infant weight (as opposed to self-reported weights) (Heerman et al., 2014)
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From page 115... ...
From Science to Clinical Application: Infancy Barkin identified two potential clinical applications of scientific evidence indicating that poor nutrition during pregnancy, with rapid infant catch-up growth, leads to later increased offspring adiposity, hyperphagia, and hyperinsulinemia. First is the promotion of infant appetite regulation, perhaps by training providers to discuss with parents how to recognize satiety cues.
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From page 116... ...
Toddlers also tend to imitate the world around them, including how others are eating and playing. Barkin suggested that two potential clinical applications of these observations are, first, to support and reinforce toddler self-regulation and, second, to set normative habits in nutrition and physical activity.
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From page 117... ...
The researchers found that both the control and intervention groups started with some initial ties and that both groups developed additional ties over the course of the 3-month study, but the intervention treatment had been designed so that by the end of the study, the intervention group had a much more significant and dense social network. Ø41 percent of LaƟno preschoolers already overweight ØThose that parƟcipated in the intervenƟon group were 2× as likely to change their weight category to normal ØThose in the control group increased their BMI FIGURE 5-1 Change in percentage of overweight children following a skills- uilding b intervention where the focus was on improving health for both the parents and child and helping them to use their built environment to reinforce healthy habits.
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From page 118... ...
; linking to effective programs for postpartum weight loss to better prepare women for a next pregnancy; teaching parents about satiety versus hunger cues and about soothing approaches that can be used during early infancy; reassessing recommendations for appropriate weight gain during infancy and rethinking catch-up growth parameters for infants who are premature or small for gestational age; including families in setting nutrition and physical activity goals during toddlerhood for themselves and their child; and linking to trusted, effective community programs. PANEL DISCUSSION WITH SPEAKERS Following Shari Barkin's presentation, a panel discussion with the speakers led to further discussion of breastfeeding and its association (or lack thereof)
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From page 119... ...
Stein replied that the differential susceptibility, or manifestation, of exposures seen in the two Dutch Hunger Winter studies were based on very small sample sizes in a very select population (Ravelli et al., 1999; Stein et al., 2007)
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From page 120... ...
. Another workshop participant commented on Gillman's suggestion that animal studies be more like human randomized controlled trials.
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