Lead exposure decreased IQs in older Americans, study suggests
A recent study by Duke University estimated that lead exposure has caused a decrease in the intelligence quotient (IQ) of more than 170 million Americans alive today, around half of the United States population.
The study was published in the journal Proceedings of the National Academy of Science and led by Michael McFarland, PhD, associate professor of sociology at Florida State University. The study analyzed data from the National Health and Nutrition Examination Survey (NHANE) that measured the blood-lead level (BLL) of nearly 12,000 children aged one to five from 1976 to 1980 to 2015 to 2016, along with population estimates from the U.S. Census, the Human Mortality Database, and the United Nations. Researchers estimated BBLs from 1940 to 1975 through data on leaded gas consumption and the NHANE.
Researchers found that BBLs were considerably higher among those born between 1951 to 1980 than those born after 2001. According to the study, since 2015, the average lead-linked loss in cognitive ability is 2.6 IQ points per person, reducing Americans cumulative IQ score by 824 million points. Scientists determined that those born between 1951 to 1980 have a disproportionate loss of IQ points among today’s population, estimating some lost up to 10 IQ points depending on the levels of lead in their blood as a child.
“Millions of us are walking around with a history of lead exposure,” said Aaron Reuben, study author and PhD candidate in clinical psychology at Duke University in a statement. “It's not like you got into a car accident and had a rotator cuff tear that heals and then you’re fine. It appears to be an insult carried in the body in different ways that we're still trying to understand but that can have implications for life.”
This study suggests that lead exposure may have negatively impacted the cognitive abilities of half of today’s U.S. population, highlighting how widespread the damage of environmental toxins can be. For future studies, Rueben said he wants to explore the long-term effects of lead exposure on brain health in old age.
Utafiti wa hivi karibuni uliofanywa na Chuo Kikuu cha Duke ulikadiria kuwa kuambukizwa risasi imesababisha kupungua kwa IQ ya Wamarekani zaidi ya milioni 170 walio hai leo, karibu nusu ya idadi ya watu wa Marekani. Utafiti huo ulichapishwa katika jarida la Proceedings of the National Academy of Science na kuongozwa na Michael McFarland, PhD, profesa msaidizi wa sosholojia katika Chuo Kikuu cha Jimbo la Florida. Utafiti huo ulichunguza takwimu kutoka kwa utafiti wa National Health and Nutrition Examination Survey (NHEEN) ambao ulipima kiwango cha risasi ya damu ya watoto 12,000 wenye umri wa miaka 1 hadi 5, kutoka 1976 hadi 2015 hadi 2016, pamoja na makadirio ya idadi ya watu kutoka sensa ya Marekani, Hifadhidata ya Kifo cha Binadamu, na Umoja wa Mataifa. Watafiti walipima viwango vya BBL kutoka 1940 hadi 1975 kupitia data ya matumizi ya gesi yenye risasi na NHANE. Utafiti huo ulionyesha kuwa idadi ya watu waliozaliwa kati ya mwaka 1951 na 1980 ilikuwa kubwa kuliko wale waliozaliwa baada ya mwaka 2001. Kulingana na utafiti huo, tangu 2015, wastani wa kupoteza uwezo wa utambuzi unaohusiana na risasi ni pointi 2.6 kwa kila mtu, na kupunguza alama ya jumla ya IQ ya Wamarekani kwa pointi milioni 824. Wataalamu wa sayansi wamegundua kuwa watu waliozaliwa kati ya mwaka 1951 na 1980 wana kiwango kikubwa cha IQ kuliko watu wa leo, na wanakadiria kuwa baadhi yao walipoteza hadi IQ 10 kulingana na kiwango cha risasi katika damu yao wakiwa watoto. "Mamilioni yetu wanatembea huku na huku na historia ya kuathiriwa na risasi,"" alisema Aaron Reuben, mwandishi wa utafiti na mgombea PhD katika saikolojia ya kliniki katika Chuo Kikuu cha Duke katika taarifa. Si kama wewe got katika ajali ya gari na alikuwa na rotator cuff tear kwamba uponyaji na kisha wewe ni sawa. "Hii inaonekana kuwa ni ""hasifa"" inayobebwa katika mwili kwa njia tofauti ambazo bado tunajaribu kuelewa lakini ambayo inaweza kuwa na athari kwa maisha. utafiti huu unaonyesha kuwa mfiduo wa risasi inaweza kuwa na athari mbaya kwa uwezo wa utambuzi wa nusu ya idadi ya watu wa leo wa Marekani, ikionyesha jinsi uharibifu wa sumu za mazingira unaweza kuwa." Kwa ajili ya utafiti wa baadaye, Rueben alisema anataka kuchunguza athari za muda mrefu za kuambukizwa risasi kwenye afya ya ubongo katika uzee.