Obesity is the scourge of the 21st century.  Carrying extra weight in adulthood causes diabetes and heart disease.  In childhood, obesity not only presages adult obesity, but it also leads to asthma, depression, orthopedic problems and other ills among children themselves.  Rates of obesity in children and adults are just about as high as they can be in western societies, and they are rapidly increasing in the developing world.  By 2030, close to a billion people across the globe will have diabetes or prediabetes.
Treating obesity is devilishly difficult.  Human physiology resists weight loss because we evolved during a time when it was advantageous to pack on the fat.  We didn’t know whence or when our next meal would come, and it required physical activity to get it.  But now it’s feast all the time, and by expending minimal energy we can drive to the supermarket at any time of night and our kids have fast food and convenience stores within arm’s reach.  Obesity also resists treatment because of learned behaviors and socio-cultural norms.  Once present, all of these cycles are hard to break.

For these reasons, much of the research in our Obesity Prevention Program focuses on prevention starting at early stages of human development, even before birth, when the first drivers of obesity and chronic disease make their marks. Because these early periods are developmentally plastic, some of these marks “program” our bodies for a lifetime of increased risk for obesity even if the stimulus isn’t present later.  Such critical or sensitive periods are well known in animal studies.  We and others are starting to find them in human populations as well. 

One of the ways to study population effects of early determinants is by mounting a cohort study beginning with women in pregnancy and following them and their children.  That’s exactly what we are doing in the long-running NIH-funded study Project Viva .  We recruited women in the 1st trimester of pregnancy back in 1999-2002 and have repeatedly visited them and their children since, now through the early teen years.

In a recent publication from Project Viva, we found that the combination of 2 prenatal factors—maternal smoking and excessive gestational weight gain—and 2 factors in infancy—shorter breastfeeding duration and inadequate nightly sleep—predicted a high amounts of fatness in mid-childhood (age 7-10 years).  Mother-infant pairs without these 4 risk factors conferred a 4% chance of obesity in childhood, whereas the presence of all 4 was associated with a 28% risk.  That’s a big difference from just four factors.

The findings from this observational study support the hypothesis that intervening to improve these (and other) risk factors would prevent a large chunk of childhood obesity. We and others are now conducting several intervention studies to examine this hypothesis.  And that’s a story for another post.



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