Demolition Activities and Children's Lead Levels in St. Louis City

The goal of this study is to examine the relationship between demolition of housing units in St. Louis City and blood lead levels in children living in the vicinity of the demolition site.

Children’s blood lead levels have been decreasing steadily over the past 25 years, due primarily to the elimination of lead in gasoline and paint.  Nevertheless, a reservoir of lead remains in many of the country’s older homes, a direct result of the use of leaded paint prior to 1978, and particularly before 1950.  Today, older homes, particularly those in disrepair, represent the single most important factor contributing to children’s blood lead levels.  Contaminated paint, dust and soil provide a ready hazard to children whose major route of exposure is ingestion due to the normal hand to mouth activity of toddlers and children. Inhalation of airborne lead is also a potential exposure pathway. Researchers have found that effective dust control and lead-based paint remediation results in decreases in children’s blood lead levels.  However, it has also been found that home renovation and repair might be a potential source of exposure to lead. Once released from its source (primarily lead-based paint, paint chips), lead remains in the environment without degradation. If not properly contained, demolition of housing units that contain lead paint may become a new source of exposure due to the release of lead dust. 

The burden of childhood lead poisoning is particularly high in St. Louis, Missouri.  The prevalence of elevated lead levels among children in St. Louis is consistently and significantly higher than the national estimates of 2.2 percent reported by the most recent National Health and Nutrition Examination Survey (NHANES).  Furthermore, the housing stock in St. Louis is particularly old, with more than 80% of all structures built prior to 1950. 

Over the past several years, St. Louis has been the focus of a significant effort to replace older or unwanted structures with new ones.  This effort involves demolition of old housing.  A preliminary evaluation of the geographic correlation between aggregated elevated lead levels and demolition activities identified certain areas in St. Louis where high lead levels were coexistent with demolition activities.  A more rigorous study was needed to determine the impact, if any; demolitions have on children’s lead levels.

A retrospective epidemiological study was conducted to examine the relationship between demolition of housing units and blood lead levels of children living near demolitions sites. St. Louis, Missouri was selected as the study site because of the prevalence of elevated childhood blood lead levels, ongoing demolition of housing structures, and the availability of quality data on both children’s blood lead levels and demolitions.

The study objective was to examine whether children exposed to demolition(s) are more likely to have higher blood lead (BPb) levels than children not exposed to demolition activity, controlling for other known risk factors.  The specific aims of the study were:

• To determine if demolition activity has any effect on the blood lead levels of children living on the block where the demolition occurred.

• To determine if the magnitude of the effect, if any, differs by the number of demolitions on the block.

Tulane University Center of Excellence for Environmental Public Health Tracking
Missouri Department of Health and Senior Services, Office of Surveillance
City of St. Louis Health Department
City of St. Louis Building Division

A retrospective cohort study was conducted in St. Louis City, Missouri. The sampling frame included data from two routinely collected data sources.  Blood lead data and relevant covariate information were abstracted from the Missouri Childhood Lead Poisoning Prevention Program (CLPPP) lead surveillance system.  Demolition data were obtained from the St. Louis City Demolition Permit database maintained by the City’s Building Division.

A child’s lead test was included in the study if it was drawn between January 1, 2002, and December 31, 2002 and if the child lived on a block with at least one demolition.  Children who had a BPb test within 45 days of a demolition were considered “exposed”. Children who did not have a BPb test within 45 days of the demolition were considered “unexposed”.  The dependent variable was the child’s blood lead level. Covariates included date of birth, sex, race and age of the house where the child resided at the time of the blood draw.  We conducted multivariate regression analysis of blood lead level and demolition, controlling for relevant covariates, to determine whether living in the vicinity of a demolition was associated with an increased BPb, and whether the number of demolitions on the child’s block was associated with an increased in BPb. 

When controlling for known risk factors, being exposed to a demolition is not related to an increase in BPb level.  However, being exposed to multiple demolitions, after controlling relevant covariates, is related to an increase in BPb level.

This study suggests that demolition in low-income urban areas may exacerbate lead hazards and pose a new risk to neighborhood residents.  Although being exposed to multiple demolitions was related to an increase in BPb, the most important predictors in our model were age of housing and race. Further, the increase seen in blood lead level was not clinically significant.  Therefore, recommendations made to the buildings division included continuation of current lead containment efforts with increased attention to areas where multiple demolitions are scheduled to occur.