Health Effects of Lead

Health Effects of Lead

 

■ High-level lead exposure leading to lead poisoning can impact various parts of the body. 

High-level lead exposure leading to lead poisoning can impact various parts of the body. This includes gastrointestinal disorders such as lead colic, as well as impairments in the nervous and muscular systems (peripheral neuropathy, loss of sensation in the hands, etc.), and disorders of the central nervous system. Examining cases in the United States, clinical symptoms in individuals exposed to lead are often diverse and mild, with lead encephalopathy-related central nervous system disorders being very rare. However, exposure to organic lead, such as tetraethyl lead (TEL), often leads to central nervous system disorders. Nevertheless, high-level lead exposure, except in certain occupational settings, is rare in recent times.

 

■ The numerous epidemiological studies revealed that even very low levels of lead exposure are associated with neurological development in children and cardiovascular diseases in adulthood.

Until the 1970s, lead poisoning from high-level lead exposure was the primary public health concern. However, through numerous epidemiological studies on birth cohorts conducted thereafter, it was revealed that even very low levels of lead exposure, previously thought to have little impact on health, significantly affect children's growth and development, particularly neurological development. Maternal blood lead levels during pregnancy were associated with a higher risk of spontaneous abortion, as well as lower birth weight, length, and head circumference at birth. Lead significantly influences brain development from infancy to adolescence, with higher maternal blood lead levels during pregnancy associated with lower cognitive and motor development in children, and these differences tend to persist and worsen with age. The relationship between maternal blood lead levels and intelligence development has been consistently observed even at levels below 5-10 µg/dL. Such neurodevelopmental disorders affect children's intelligence, problem-solving skills, memory, and planning abilities, reducing academic achievement and increasing the risk of attention deficit hyperactivity disorder (ADHD), along with impairments in motor function. According to recent studies, cognitive and academic deficiencies can occur even when blood lead levels are below 5.0 μg/dL.

In adulthood, low-level lead exposure is reported to increase the risk of cardiovascular diseases, including hypertension, and is also being investigated for its association with neurodegenerative diseases in the elderly.

 

■  Reference values

As preventive measures, individuals exposed to lead in occupational settings should undergo pre-placement and periodic health assessments to determine excessive lead absorption. Additionally, regular biological monitoring should be conducted to evaluate lead exposure levels within the body. Proper management of the work environment and protective equipment is crucial for preventing lead exposure.

In daily life, efforts should be made to minimize lead exposure. Particularly for children and women of childbearing age, reducing lead exposure in their living environments, such as household paint, toys, school supplies, and playgrounds, is essential. Women of childbearing age should also be cautious of lead exposure in the environment.

There is no known safe blood lead concentration Each institution recommends maintaining blood lead levels below the following concentrations.

 

• WHO (World Health Organization): Blood lead level of 5 μg/dL (1)
• US CDC (Centers for Disease Control and Prevention): Blood lead level of 3.5 μg/dL for children (2)

< CDC: Lead Poisoning is 100% Preventable. (3)>

 

■   References

The content is primarily based on Casarett and Doull’s Toxicology 9th edition and the NTP Monograph Health Effects of Low-Level Lead

(https://ntp.niehs.nih.gov/sites/default/files/ntp/ohat/lead/final/monographhealtheffectslowlevellead_newissn_508.pdf).

(1)   Lead poisoning (who.int): https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health. Access date: 2024-03-01

(2)   Lead:(https://www.cdc.gov/niosh/topics/lead/referencebloodlevelsforadults.html). Access date: 2024-03-01

(3)   Lead Poisoning is 100% Preventable Infographic: https://www.cdc.gov/nceh/lead/prevention/infographic-lead-poisoning-preventable.htm. Access date: 2024-03-01