College of Nursing

lead and your health

Tremendous progress has been made in the United States to reduce lead exposure and to lower blood lead levels. Much of this success is due to research supported by the National Institute of Environmental Health Sciences (NIEHS) and others who have helped to identify and reduce the health effects of lead exposure in children and adults.

What is lead?

Lead is a naturally occurring metal found deep in the ground. It occurs in small amounts in ore, along with other elements such as silver, zinc, or copper. Even though it is found in small amounts, there is an abundant supply of lead throughout the earth. Because it is widespread, and easy to extract and work with, lead was used for hundreds of years in a wide variety of products found in and around homes, including paint and gasoline. 

 Where is lead found now?

Lead can still be found in lead-based paint used in older homes, contaminated soil, household dust, drinking water pumped through leaded pipes, lead crystal, lead-glazed pottery, airplane fuel, some toys, and some inexpensive metal jewelry. Until 1978, lead paint was commonly used on the interior and exterior of homes. Deteriorated lead paint in older housing remains the most common source of lead exposure for children in the United States.

How does lead get into the body?

Lead can get into your body in two ways - through breathing it in or by eating it. For example, lead can enter the body through eating or inhaling paint dust or chips. The soil around your home can pick up lead from sources such as exterior paint. Lead can also enter your drinking water through your plumbing.

Who is most vulnerable to the effects of lead? Both children and adults are vulnerable to the effects of lead. Young children under the age of 5 are particularly vulnerable, because their body, brain, and metabolism are still developing. Two-year-olds tend to have the highest blood level concentration, because they put many things into their mouth, including toys or other products that may contain lead.

How do you measure lead exposure?

Blood tests are typically used to measure the concentration or amount of lead in your blood, and are used to detect lead in both children and adults. Although long-standing national surveys, such as the National Health and Nutrition Examination Survey, show that blood lead levels have decreased over the last 30 years for all age groups, black, non-Hispanic children have higher levels of lead detectable in their blood. A person's blood lead level reflects both the current environmental exposure and previous lead exposures stored in body tissues, primarily in bone. 

Measuring bone lead requires specialized testing equipment, whereas blood lead testing is the most readily available indicator for lead exposure.

What are the effects of lead in children?

Exposure to lead can have a wide range of effects on a child's development and behavior. Blood lead levels less than 10 micrograms per deciliter (µg/dL) are associated with increased behavioral effects, delayed puberty, and decreases in hearing, cognitive performance, and postnatal growth or height.
Some of these health effects are found even at low blood lead levels less than 5 µg/dl, including lower IQ scores, decreased academic achievement, and increases in both behavioral problems and attention ­related behaviors. There is a wide range of lead­associated behavioral effects in the area of attention. Attention deficit hyperactivity disorder (ADHD) is one example on the more severe end of the spectrum.

Children Decreased academic achievement, IQ and specific cognitive measures; increased incidence of problem and attention-related behaviors Adults  Decreased kidney function, maternal blood lead associated with reduced fetal growth	Blood lead levels below 5 µg/dl
Children Delayed puberty, reduced postnatal growth, decreased IQ and hearing Adults Increased blood pressure, risk of hypertension, and incidence of essential tremor	Blood lead levels below 10 µg/dl

What are the health effects of lead in adults? 

Lead exposure has been linked to a number of health effects in adults. As a general rule, the more lead you have in your body, the more likely it is you'll have health problems. High blood lead levels greater than 15 µg/dl are associated with cardiovascular effects, nerve disorders, decreased kidney function, and fertility problems, including delayed conception and adverse effects on sperm and semen, such as lower sperm counts and motility.

Blood lead levels below 10 µg/dl are associated with decreased kidney function and increases in blood pressure, hypertension, and incidence of essential tremor, a degenerative disorder of the central nervous system whose most recognizable feature is a tremor of the arms or hands during voluntary movements, such as eating and writing. There is also evidence showing that adults who have low levels of exposure to lead less than 5 µg/dl may have decreased kidney function.

Pregnant women need to be particularly careful around lead. Maternal blood lead levels less than 5 µg/dl are associated with reduced fetal growth. Because the effects of lead are different for everyone, more research needs to be done to fully understand the health effects.

A 2004 study, supported by NIIEHS, also showed that lifetime lead exposure may increase the risk of developing cataracts, a clouding of the eye lens resulting in partial loss of vision, which can be common in older people. Most adults with elevated blood lead levels are exposed to lead at work. Those in occupations related to mining, ironwork or welding, construction, renovation and remodeling activities, smelters, firing ranges, the manufacture and disposal of car batteries, automobile radiator repair, metal shop work, and the manufacture of pottery or stained glass are particularly at risk for lead exposure. 

How much lead is harmful?

No amount of lead is safe. Eliminating all lead exposure in our environment is our best course of action.
New findings from NIEHS-supported grantees, as well as the National Toxicology Program (NTP), provide support for many adverse health effects in both children and adults at blood lead levels below 10 µg/dL, and, for some, below 5 µg/dl.

These findings add to the body of evidence that led the Centers for Disease Control and Prevention (CDC), in 2012, to update its reference value to identify children who have been exposed to lead and who require case management. The new level is based on the population of children aged 1-5 years, in the U.S., who are in the top 2.5 percent of children when tested for lead in their blood. Currently, this means that public health actions be initiated for children with blood lead levels above 5 µg/dl. Prior to this, children were identified as having a blood lead level of concern if the test result was 10 µg/dL or more. As part of a shift in focus to primary prevention of lead exposure, the CDC has dropped the level of concern terminology, since no safe blood lead level in children has been identified. The new, lower value gives parents, doctors, and public health officials an opportunity to prevent and reduce lead exposure very early on. 

Are there treatments to remove lead from the body? Yes, medications exist that can remove some lead from the body. However, no medical treatment is recommended for children with blood lead levels lower than 45 µg/dl. Medications, such as succimer, have been shown to significantly reduce lead in children with very high blood lead levels. Although succimer lowered blood lead about 25% in the short term, it did not improve IQ or other test scores. This reinforces the need for prevention. Treatment after the fact does not undo the damage caused by lead. Children must be protected from being exposed at all.