Adult Exposure to Lead

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“Children in approximately 4 million households in the United States are being exposed to high levels of lead.” As I discuss in my video The Effects of Low-Level Lead Exposure in Adults, “Despite the dramatic decline in children’s blood-lead concentrations over the decades, lead toxicity remains a major public health problem”—and not just for children. Yes, lead is “a devastating neurotoxin,” with learning disabilities and attention deficits in children beginning around blood lead levels of 10 mg/dL, which is when you start seeing high blood pressure and nerve damage in adults, as you can see at 0:41 in my video. But, the blood levels in American adults these days are down around 1 mg/dL, not 10 mg/dL, unless you work or play in an indoor firing range, where the lead levels in the air are so high that more than half of recreational target shooters have levels over 10 mg/dL or even 25 mg/dL.

In fact, even open-air outdoor ranges can be a problem. Spending just two days a month at such a range may quadruple blood lead levels and push them up into the danger zone. What if you don’t use firearms yourself but live in a house with someone who does? The lead levels can be so high that the Centers for Disease Control and Prevention advises those who go to shooting ranges to take “measures to prevent take-home exposure including showering and changing into clean clothes after shooting…, storing clean clothes in a separate bin from contaminated clothing, laundering of non disposable outer protective clothing…and leaving at the range shoes worn inside the firing range,” among other actions. Even if none of that applies and your blood levels are under 10 mg/dL, there is still some evidence of increased risk of hand tremors, high blood pressure, kidney damage, and other issues, as you can see at 1:44 in my video. But what if you’re down around a blood lead level of 1 mg/dL, like most people?

“Blood lead levels in the range currently considered acceptable are associated with increased prevalence of gout,” a painful arthritis. In fact, researchers found that blood levels as low as approximately 1.2 mg/dL, which is close to the current American average, can be associated with increased prevalence of gout. So, this means that “very low levels of lead may still be associated with health risks,” suggesting “there is no such thing as a ‘safe’ level of exposure to lead.”

Where is the lead even coming from? Lead only circulates in the body for about a month, so if you have lead in your bloodstream, it’s from some ongoing exposure. Most adults don’t eat peeling paint chips, though, and autos aren’t fueled by leaded gas anymore. There are specific foods, supplements, and cosmetics that are contaminated with lead (and I have videos on all those topics), but for most adults, the source of ongoing lead exposure is from our own skeleton. I just mentioned that lead only circulates in the body for about a month. Well, where does it go after that? It can get deposited in our bones. “More than 90% of the total body lead content resides in the bone, where the half-life is decades long,” not just a month. So, half or more of the lead in our blood represents lead from past exposures just now leaching out of our bones back into our bloodstream, and this “gradual release of lead from the bone serves as a persistent source of toxicity long after cessation of external exposure,” that is, long after leaded gasoline was removed from the pumps for those of us that who were around back before the 1980s.

So, the answer to where the lead comes from is like Pogo’s We’ve met the enemy and he is us or that classic horror movie scene where the call is coming from inside the house.

The amount of lead in our bones can actually be measured, and research shows higher levels are associated with some of our leading causes of death and disability, from tooth decay and miscarriages to cognitive decline and cataracts. “Much of the lead found in adults today was deposited decades ago. Thus, regulations enacted in the 1970s were too late” for many of us, but at least things are going in the right direction now. The “dramatic societal decreases” in blood lead in the United States since the 1970s have been associated with a four- to five-point increase in the average IQs of American adults. Given that, a “particularly provocative question is whether the whole country suffered brain damage prior to the 1980 decreases in blood lead. Was ‘the best generation’ really the brain damaged generation?”

I’m such a sucker for science documentaries, and my favorite episode of Cosmos: A Spacetime Odyssey was The Clean Room, which dealt with this very issue. Trivia: Carl Sagan was my next-door neighbor when I was at Cornell!

If you want to find out How the Leaded Gas Industry Got Away with It, check out that video. How the Lead Paint Industry Got Away with It is similarly scandalous. Lead in Drinking Water offers the modern-day tale of what happened in Flint, Michigan, and “Normal” Blood Lead Levels Can Be Toxic explores the impacts on childhood development.

I close out this extended video series on lead with information on what we can do about it:

Interested in learning more about lead being absorbed and released in our bones, and how calcium supplements may affect that process? See The Rise in Blood Lead Levels at Pregnancy and Menopause and Should Pregnant Women Take Calcium Supplements to Lower Lead Levels?.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

 

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