Low Level Lead Exposure May Lead to Kidney Damage: Study

Amid continuing concerns about the risk of lead paint poisoning in older homes, the findings of a new study suggest that even very low lead blood levels can still cause kidney damage. 

In a study published in the February issue of the medical journal Environmental Health Perspectives (EHP), researchers from Korea looked at the mechanisms for potential links between lead exposure and kidney damage.

The findings suggest that aging red blood cells, known as erythrocytes, which can collect heavy metals, may play a key role to kidney-damage associated.

Researchers incubated lead-exposed human erythrocytes and conducted a number of tests and analyses on the cells and on rats. They found iron was being deposited in the kidneys, causing oxidative stress in the renal tissues.

In an accompanying editorial, Julia R. Barrett, an editor and science writer for EHP noted that the current evidence indicates that kidney damage can occur at blood lead levels as low as 5 micrograms of lead per deciliter of blood, or 5 μg/dL.

“Specific populations, including people with preexisting kidney disease, diabetes, or hypertension, may be at even greater risk of effects of low-level lead exposure,” Barrett said. “Both in vivo and in vitro data highlight oxidative stress as a factor in lead-associated kidney damage, but it has been unclear how the stress is generated.”

The study’s findings, which Barrett indicates need to be further researched and duplicated, focus on the risks of lead poisoning to adults and the rest of the population in the form of kidney damage, which may be often overlooked due to the focus on lead exposure in children, which can cause developmental problems, brain damage and even death.

In 2012, the U.S. Centers for Disease Control and Prevention lowered the blood lead level (BLL) required for a child to be considered as suffering from lead poisoning will be dropped from 10 micrograms of lead per deciliter to five.

The threshold for a lead poisoning diagnosis is reassessed every four years, according to the CDC. However, the blood poisoning level only applies to children ages six and under. Older children and adults do not have a lead poisoning threshold.

However, according to Barrett, adults may be at risk of kidney damage even at BLLs set as a threshold for children.

The CDC estimates that 535,000 children ages 1-5, or about 2.6% of such children in the U.S., have levels of lead in their blood that place them at risk for adverse health effects. To come up with that number, the CDC analyzed data from the National Health and Nutrition Examination Survey from the years 1999 to 2002, and 2007 through 2010.

Lead poisoning for children can result in nervous system injury, brain damage, seizures or convulsions, growth or mental retardation, coma and even death for young children.

One of the more common causes of of lead poisoning is lead-based paint, which was banned in the United States in 1978 due to the risk of severe and permanent brain damage and developmental problems, particularly in children. However, a number of older homes still contain the toxic paint on the walls, and if it flakes or peals off, young children could ingest the paint chips or breathe dust that comes from the paint, resulting in lead poisoning.