Understanding Lead Data
What Is Lead Poisoning?
Lead is a metal that has many uses. It can be found in many places around a home such as in paint; dust from lead paint; soil and dirt; and pottery, crystal or ceramic dishes. When lead gets into the body it is poison and harms people. Anyone can get lead poisoning. However, lead is most dangerous to children under the age of six. Essentially causing brain damage, lead poisoning can result in learning difficulties, loss of IQ, and behavioral problems that are irreversible. Lead poisoned children are likely to suffer life-long consequences as a result of their exposure at a young age.
How Is Lead Measured And What Is A Safe Level?
Unlike many elements that are toxic in large amounts, but necessary for the proper function of the body in small amounts, there is no known use for lead in the body. Therefore, any lead in the body is toxic and ideally the amount of lead in the body should be zero!
We generally measure the amount of lead in a child’s body through the blood, the result being a Blood Lead Level (or BLL). The test to determine a child’s BLL is relatively inexpensive and requires only a simple blood draw. BLLs are reported as the number of micrograms of lead per deciliter of whole blood (abbreviated as mcg/dL).
Since lead is all around us, it is unlikely that any child could ever have no lead in his or her system. The federal Centers for Disease Control and Prevention (CDC) decided that a BLL less than 10mcg/dL is not a reason for concern. Levels greater than or equal to 10mcg/dL are considered to be an elevated blood lead level (EBL), and actions should be taken to lower the level to below 10.
What’s The Difference Between A Capillary (“Fingerstick”) And Venous Blood Sample?
A blood sample can be obtained from a child’s capillaries with a simple prick to the finger or from a vein with a hypodermic needle. A capillary or fingerstick sample is easier to obtain (it can be done by someone with minimal training) and usually less traumatic to the child than a venous sample. If proper techniques are used, the two tests are not likely to produce different results. If performed improperly, however, the fingerstick sample may become contaminated with dust and dirt on the child’s skin. This may result in a false positive, that is the reporting of a much higher BLL than the child actually has.
Capillary tests are often used to screen children for lead poisoning. If a fingerstick test result comes back high, the child will have to return to the doctor to have a venous test to confirm the results. In the data presented on prevalence of lead poisoning, no differentiation was made between venous and fingerstick tests.
What Services Does The State Provide For Children Who Are Lead Poisoned?
Environmental Inspections
The Rhode Island Department of Health (HEALTH) performs comprehensive environmental inspections for children with a “significantly elevated blood lead level”. Originally, only venous samples of 25mcg/dL or higher were considered significantly elevated. This level was dropped to a venous sample of 20mcg/dL in October of 1998. In July 2001, this definition was expanded to include “persistent BLLs of 15 to 19 mcg/dL” which is defined as “any two tests (fingerstick or venous) at least 90 days but less than 365 days apart of at least 15 mcg/dL”.
Home-Based Education
Parents of children with BLLs of 15-19 mcg/dL (non-persistent) receive home-based education from one of the four certified lead centers, to help identify potential lead hazards and offer advice on protecting their children from lead. Out of 76 children tested for the first time with BLLs of 15-19 in year 2007, and who had subsequent blood tests since then, 72.1% of them haven't had a blood lead result at 15 or above again. This means that 72.1% of the children with BLLs of 15-19 do not become significantly lead poisoned.
Educational Materials
Parents of children with BLLs between 10 and 14 mcg/dL receive lead poisoning prevention brochures from HEALTH through the mail.
Where Does HEALTH Get Data On Blood Lead Levels?
All BLL results are to reported to HEALTH. Screening tests are required to be analyzed by the state laboratory or at labs approved by the Department. Any licensed clinical lab can process diagnostic tests of a suspected lead poisoned child (for whom results are needed immediately for medical management), but the results must be promptly reported to HEALTH. Screening results are electronically transferred to the Lead Program’s database on a daily basis, with diagnostic results added as they are received. Since the database includes all BLLs, along with demographic information on the child, the Program has the information needed to conduct epidemiological studies and produce reports.
It should be noted, however, that HEALTH only has information on the children who receive a lead test. We have no information upon which to make assumptions about the children who are NOT screened, and all rates are by definition only amongst screened children.
How Does HEALTH Calculate Screening Rates If the Database Only Has Information On Children Screened?
The database provides reliable data on the number of children who actually had a lead test. We must look elsewhere for the total number of children who should be tested.
HEALTH uses data from the KIDSNET system. KIDSNET is a Health Department tracking system for children and doctors. All children born in the state of Rhode Island starting on 1/1/97 have a record created in KIDSNET. Children born out of state who move into the state will have a record created should they use a pediatrician connected to KIDSNET or participate in a program which provides data to KIDSNET (such as the Early Intervention Program or WIC).
What Accounts For The Large Decline In The Prevalence Of Elevated Blood Lead Levels Over The Last Decade?
Frankly, no one knows. While thousands of lead safe certificates have been issued to dwellings across the state, they are not numerous enough to account for the change – in other words the drop is not a result of children living in certified lead safe units. There are a couple of reasonable theories, however, which may help to explain it. The awareness of lead poisoning and its prevention seems to have greatly increased. Parents and property owners have almost certainly done more to address the environmental sources of lead. In addition, the promotion of regular screening has likely allowed parents and doctors to catch a slightly elevated blood lead level and discuss the importance of lead safety before the child could become lead poisoned. It is quite likely that we are still seeing some of the benefit from the elimination of lead in gasoline carried out in the late 1980s. Finally, it is possible that the good economy of the mid to late 90s allowed families to provide a solid diet (a lack of which can be factor in increased lead absorption) and allowed rental property owners to invest more in maintenance.
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