Elise Miller, MEd, CHE Director, and Ted Schettler, MD, MPH, Science Director at SEHN and CHE, contributed the following article to the current edition of San Francisco Medicine, focused on human health and the environment, and especially the effects of early-life exposures. The full article can be found on the San Francisco Medical Society’s website. Join CHE on December 2nd for a call with contributors to the journal as they discuss neurotoxicants, climate change, cancer, and much more.
Upward trends in a number of childhood diseases and disabilities are featured almost daily in the media. As many as one in six children in the US has a neurodevelopmental disability, including autism, ADHD, and speech or cognitive delays. The number of children needing special education has increased by 200 percent from a quarter century ago. The incidence of childhood leukemia and brain cancer is also on the rise, and asthma is still the number one reason for school absenteeism among school children.
Meanwhile, we have been learning a great deal more about how children’s earliest experiences, beginning in utero, can significantly influence their lifelong health.
Many studies show that “toxic stress”–intense, sustained adverse experiences–in childhood increases the risk of many health and behavioral problems in the short and long term, including intellectual delays, obesity, diabetes, and heart disease. This evidence has in turn prompted a surge of programs that provide support for new mothers and improved child care, such as Zero to Three and Early Head Start.
Other environmental influences on fetal development, starting even before conception, can of course be critical for lifelong health as well. Initiatives like the Program for Women, Infants and Children (WIC) take this into consideration with their emphasis on healthy nutrition before, after and during pregnancy. Efforts to address other social stressors like poverty and violence are also included in some maternal health programs in different health care systems as well as at local, county, and state levels across the country.
Various biologic mechanisms mediate the influence of environmental variables on child development, including genetic and epigenetic changes, altered molecular signaling patterns, and influences on hormonal and metabolic set points, which can lead to disturbances of organ structure and function over varying timeframes.
Another Highly Influential Factor: Chemical Exposures in Early Life
In addition to excessive stress and inadequate nutrition, a large and growing body of research shows that the developmental effects of pre- and post-natal exposures to toxic chemicals–now ubiquitous in air, water, food, soil, and consumer products–must also be considered. Most chemicals circulating in maternal blood can and do pass through the placenta and can adversely impact the developing fetus. Lead, alcohol, mercury, some pesticides, and flame retardants are among the best known, but in its Proposition 65 program, California lists 652 chemicals as reproductive/developmental toxicants. Biomonitoring programs, like CDC’s NHANES, show how commonly the general population is exposed to chemicals that can interfere with normal development with lifelong health consequences.
Continue reading the article on pages 10 and 11 of the journal.