Featured Research

from universities, journals, and other organizations

Workers Exposed To Lead Show More Cognitive Problems Later In Life

Date:
January 13, 2009
Source:
American Psychological Association
Summary:
Both the developing brain and the aging brain can suffer from lead exposure. For older people, a buildup of lead from earlier exposure may be enough to result in greater cognitive problems after age 55, according to a follow-up study of adults exposed to lead at work.

Both the developing brain and the aging brain can suffer from lead exposure. For older people, a buildup of lead from earlier exposure may be enough to result in greater cognitive problems after age 55, according to a follow-up study of adults exposed to lead at work.

Related Articles


A full report appears in the January issue of Neuropsychology, which is published by the American Psychological Association.

From the Graduate School of Public Health and the School of Medicine at the University of Pittsburgh, the authors reported that cognitive problems were linked to cumulative exposure.

The researchers followed up on the 1982 Lead Occupational Study, which assessed the cognitive abilities of 288 lead-exposed and 181 non-exposed male workers in eastern Pennsylvania. The lead-exposed workers came from three lead battery plants; the unexposed control workers made truck chassis at a nearby location. At both points in time, all the workers were given the Pittsburgh Occupational Exposures Test battery, which includes measures of five primary cognitive domains: psychomotor speed, spatial function, executive function, general intelligence, and learning and memory.

In 1982, lead-exposed workers were found to have an average blood lead level of 40 micrograms per deciliter (ug/dL), well above normal. Pennsylvania workers found to have 25 ug/dL or more must be taken off the job. In 1982, the unexposed workers had an average blood level of 7.2, within normal limits.

In 2004, the current study followed up with 83 of the original lead-exposed workers and 51 of the original non-exposed workers. Researchers measured current lead levels in their blood and cumulative lead levels through special X-rays of the tibia, or lower leg bone (bone is the final repository of circulating blood lead, where it has a half life of about 30 years). Researchers also re-administered the test battery to assess cognitive performance relative to both measures of lead.

Among the lead-exposed workers, men with higher cumulative lead had significantly lower cognitive scores. The clearest inverse relationships – when one went up, the other went down – emerged between cumulative lead and spatial ability, learning and memory, and overall cognitive score.

This linkage was more significant in the older lead-exposed men, of at least age 55. Their cognitive scores were significantly different from those of younger lead-exposed men even when the researchers controlled for current blood levels of lead. In other words, even when men no longer worked at the battery plants, their earlier prolonged exposure was enough to matter.

The mild deficits, although not clinically significant, were consistent with other studies that show previous exposure to lead is, according to the authors, "particularly detrimental to the aging brain and that specific cognitive domains may be particularly vulnerable."

Scientists have been investigating how lead damages the brain, especially the hippocampus and frontal cortex, seats of memory and learning. Lead exposure also puts people at greater risk for high blood pressure, which itself weakens cognition -- one possible pathway by which lead can cause problems.

The men who built lead batteries were exposed to it in the air and through their skin. Other occupations, including semiconductor fabrication, ceramics, welding and soldering, and some construction work, also may expose workers. The authors wrote that, "Increased prevention measures in work environments will be necessary to reduce [lead exposure] to zero and decrease risk of cognitive decline."


Story Source:

The above story is based on materials provided by American Psychological Association. Note: Materials may be edited for content and length.


Journal Reference:

  1. Khalil et al. Association of Cumulative Lead and Neurocognitive Function in An Occupational Cohort. Neuropsychology, 2009; 23 (1): 10-19 [link]

Cite This Page:

American Psychological Association. "Workers Exposed To Lead Show More Cognitive Problems Later In Life." ScienceDaily. ScienceDaily, 13 January 2009. <www.sciencedaily.com/releases/2009/01/090112093332.htm>.
American Psychological Association. (2009, January 13). Workers Exposed To Lead Show More Cognitive Problems Later In Life. ScienceDaily. Retrieved March 27, 2015 from www.sciencedaily.com/releases/2009/01/090112093332.htm
American Psychological Association. "Workers Exposed To Lead Show More Cognitive Problems Later In Life." ScienceDaily. www.sciencedaily.com/releases/2009/01/090112093332.htm (accessed March 27, 2015).

Share This


More From ScienceDaily



More Mind & Brain News

Friday, March 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

AAA: Distracted Driving a Serious Teen Problem

AAA: Distracted Driving a Serious Teen Problem

AP (Mar. 25, 2015) While distracted driving is not a new problem for teens, new research from the AAA Foundation for Traffic Safety says it&apos;s much more serious than previously thought. (March 25) Video provided by AP
Powered by NewsLook.com
Smartphone Use Changing Our Brain and Thumb Interaction, Say Researchers

Smartphone Use Changing Our Brain and Thumb Interaction, Say Researchers

Reuters - Innovations Video Online (Mar. 25, 2015) European researchers say our smartphone use offers scientists an ideal testing ground for human brain plasticity. Dr Ako Ghosh&apos;s team discovered that the brains and thumbs of smartphone users interact differently from those who use old-fashioned handsets. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
Many Don't Know They Have Alzheimer's, But Their Doctors Do

Many Don't Know They Have Alzheimer's, But Their Doctors Do

Newsy (Mar. 24, 2015) According to a new study by the Alzheimer&apos;s Association, more than half of those who have the degenerative brain disease aren&apos;t told by their doctors. Video provided by Newsy
Powered by NewsLook.com
A Quick 45-Minute Nap Can Improve Your Memory

A Quick 45-Minute Nap Can Improve Your Memory

Newsy (Mar. 23, 2015) Researchers found those who napped for 45 minutes to an hour before being tested on information recalled it five times better than those who didn&apos;t. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins