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Guide PHIT Data: Childhood Lead Poisoning

This dataset contains record-level pediatric blood lead testing data for children in Massachusetts. Data on childhood lead poisoning is presented by calendar year and provides blood lead screening counts and percentages and blood lead prevalence rates. Community-level data is available from 2001 onward.

Table of Contents

What you need to know

Lead poisoning is caused by swallowing or breathing lead. Lead can stay in your body for a long time. Young children absorb lead more easily than adults. The harm done by lead may never go away. Even low levels of lead can harm the health of a child. There is no safe level of lead exposure. Lead in the body can hurt the brain, kidneys, and nervous system, slow down growth and development, make it hard to learn, damage hearing and speech, and cause behavior problems. However, lead poisoning is preventable. Most children who have lead poisoning do not look or act sick. A simple screening test is the only way to identify a child with elevated blood lead levels. For this reason, state law requires that all children must be screened for lead poisoning each year through the age of three (children in high risk communities must be screened again at age four). All children must show proof of screening at least once in order to enter daycare, pre-kindergarten programs, and kindergarten. The U.S. Centers for Disease Control and Prevention (CDC) uses a reference level of 5 micrograms per deciliter (µg/dL) to identify children with blood lead levels higher than most children’s levels. This reference level is used to identify children who have been exposed to lead and who require case management by public health officials.

Lead paint continues to be the most important source of elevated blood lead levels in children. The older a house or apartment, the more likely it is to contain lead paint. Homes built before 1978 may have lead paint on the inside and outside of the building. Deteriorating paint (chipping, flaking, and peeling) and paint disturbed during home remodeling often results in the release of tiny paint chips and lead dust that children get onto their hands and into their mouth. Children can also breathe in lead dust. Lead dust also comes from opening and closing old windows. The key to preventing lead poisoning is to stop children from coming into contact with lead and managing the care of those who have been poisoned by lead. In order to do that:

  • Homes must be inspected for lead hazards
  • Lead in a child’s environment must be removed or properly contained
  • All public and health care professionals have to be educated about lead poisoning and how to prevent it
  • Children who are at risk of lead poisoning need to be tested and, if necessary, treated
  • Home renovation and repairs must be done following lead safe work practices

Lead from sources other than housing may also present a hazard to children. Other sources of lead include:

  • Ceramic dishes
  • Brass containers
  • Foreign/antique tea kettles (like samovars)
  • Stained glass
  • Large batteries
  • Bullets
  • Fishing sinkers
  • Folk medicines/cosmetics (like kohl) from other countries
  • Imported spices and herbal remedies
  • Children’s toys and jewelry
  • Drinking water
  • Soil

Information about these data

This data set was created for the MDPH Population Health Information Tool to help identify disparities in childhood lead poisoning and community health needs for public health prevention and intervention.

How prevalence is calculated:

Data on childhood blood lead poisoning is presented by calendar year. Data by calendar year provides blood lead screening percentages and blood lead level prevalence rates based on the year in which the child was tested for children between the ages of 9 and 47 months. If a child had multiple tests within the same calendar year, only the highest confirmed test is included for that year. A confirmed test result is one venous test or two capillary tests (within 12 weeks of each other) during a given year. For determining prevalence, children can be counted only once per year, but can appear in multiple years. Prevalence is the number of tests in a given blood lead level category out of all the children screened in that year within specific age ranges, per 1,000 children.

The data is stratified by year of screening, county of residence, and community of residence. The data is available by individual year as well as by an aggregate of 5 year groupings. The 5 year groupings are provided as an alternative to avoid suppression frequently found in individual years. Data is suppressed when the number of children screened or case count is between 1-5 and population or total screened is less than 1,200. These small numbers are suppressed to protect privacy.

In order to assess statistical significance, 95% confidence intervals are presented for percentages and rates. Non-overlapping confidence intervals are statistically significant. The data does not include complete race/ethnicity information.

Confirmed versus unconfirmed test results:

Confirmed blood lead levels include both venous and confirmed capillary test results. Unconfirmed blood lead levels include single capillary test results only. Estimated confirmed blood lead levels ≥5 µg/dL include both confirmed results and a proportion of unconfirmed results estimated to be truly elevated based on known capillary test reliability. This measure is used because a single capillary test does not provide adequate precision or reliability to be considered confirmatory of an elevated blood lead level. Until confirmatory testing of preliminary capillary tests 5-<10 µg/dL is uniformly adopted per the 2017 regulation requirements, a calculation is used to estimate the true number of children with blood lead levels ≥5 µg/dL.

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Additional Resources for Information about these data

Other considerations for interpreting blood lead data:

  • Blood lead prevalence results are based on only those children who have been screened. While the percentage of children screened in Massachusetts is one of the highest in the country, the blood lead prevalence results should be interpreted considering the screening percentage for the geographic area of interest.
  • When comparing rates across geographic areas, a variety of non-environmental factors, such as screening practices, can impact the prevalence of blood lead levels in children. Prevalence at the state and/or county level will not show the variation in disease burden at a more local level (i.e. community).
  • Prevalence is based on the residential location of the child and not necessarily the location of the source of exposure.
  • Numbers and rates may differ slightly from those contained in other publications. These differences may be due to file updates, differences in methodology, diagnostic techniques reported, and updates in population estimates.
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