Average height in the United States has plateaued and even seems to be declining.

This trend parallels what we see with lifespan, IQ, fertility, and also lines up with the negative trajectory on obesity. Height is typically used by demographic scientists to gauge the quality and quantity of nutrition, quality of healthcare, and overall environmental conditions in a population. Historically, we’ve seen declines in height tied to major hardships—war, economic crises, pandemics—and while height is slower to respond than other variables, it remains a critical piece of the larger puzzle.

People often blame obesity on the easy availability of calories, but I think we’ve been in that situation in the U.S. for over a century, minus a few years during the Great Depression and World War II. So something—or more likely a combination of factors—is disrupting our health, especially in children.

Some might want to dismiss this as just a demographic shift toward ethnicities that are statistically shorter, but apparently researchers have already adjusted for that, and the general conclusion is that the effect is real. It hits Black America disproportionately, which in our society tends to serve as the canary in the coal mine when it comes to negative health trends that eventually affect everyone.

We shouldn’t jump to the conclusion that this is due to any single cause. It could be nutritional, biochemical, lifestyle, social, emotional—likely a mix of them all. My suspicion is that the biggest contributors are endocrine disruptors, declining nutritional quality, demands from school and work that force people into sedentary routines, lack of outdoor play, lack of sunlight, high levels of chronic stress, and possibly even changes in family composition that alter endocrine profiles.

We’re degrading our environment in ways we don’t fully recognize, and we need to start paying attention. It’s our version of the Roman Empire’s hidden lead poisoning crisis. I’m not saying for sure it’s an environmental pollutant, but that’s high on my list of possible culprits.