On March 14, 2016, the Healthy Homes Coalition of West Michigan and the Kent County Health Department (KCHD) spoke with representatives from the Michigan Department of Health and Human Services (MDHHS) to begin exploring why there was a 30% increase in the number of children with elevated blood lead test results in Kent County in 2015. In 2014 there were 470 children with blood lead levels ≥5.0 ug/dL* in Kent County. In 2015, that number rose dramatically to 610 children. The initial request on that day was to review historical data to identify potential abnormalities by the following:
- WIC testing sites (in the City of Grand Rapids)
- Geography (zip codes)
- Time of year (quarter)
On April 24, 2016, MDHHS shared data with the Healthy Homes Coalition and KCHD. The following is a synopsis of the data presented and conclusions drawn.
WIC Testing Sites
Among the WIC testing sites in Grand Rapids (typically the sites with the most testing), the Fuller Clinic saw a 55% increase and the Sheldon Clinic saw a 88% increase in children with elevated blood test results in 2015. These sites represent 37% of the tests conducted in 2014 and 38% of 2015 tests.
Conclusion: Results of testing at these sites does not fully explain the increase in elevated tests as these sites used a consistent testing methodology throughout 2014 and 2015 . This data does reveal that the high rate of elevated blood lead tests among low-income children living in the City (WIC eligible and proximal to these clinics) is driving the increase.
Venous vs. Capillary Testing
Following the April 24 call, MDHHS pulled elevated venous test results since 2010 by quarter. The pattern for venous test results was similar to the pattern for all results (capillary and venous), although the percentage of venous tests that are high tends to be higher due to the fact that they are frequently confirmatory tests.
Conclusion: It is highly unlikely that the 2015 increase can be attributed to false-positive capillary test results or other unconfirmed capillary testing.
Time of Year
When looking at the data by calendar quarter, the peak distribution of high tests seems to be consistent with past years. Quarters 3 & 4 continue to have higher testing levels annually, with the third quarter being the peak each year. There are annual decreases in the first and second quarters, although first quarter rates rose modestly in 2014 and significantly in 2016. This pattern was observed consistently for the city as a whole and at the individual zip code level. There were only three variations to the peak levels (49504 and 49506 peaked in the 4th quarter in 2014, and 49504 peaked in the 4th quarter again in 2015).
Conclusion: Because of the repeating pattern, the time of the year does not seem to be a significant contributing factor. The increase in 2015 occurred primarily in third and fourth quarter testing (July-December). The sustained increase in the first quarter of 2016 is concerning.
Elevated blood lead test data for the past five years was categorized by zip code. All zip codes seemed to trend in a similar manner, with only minor variances. None of those variances were meaningful enough to explain the 2015 increase.
Conclusion: Geography at the zip code level is not a significant driving factor for the 2015 increase.
Following the April 24 call, KCHD requested that MDHHS provide data for the WIC clinics located outside of the city of Grand Rapids since they may serve a significant Grand Rapids client base. The Healthy Homes Coalition requested that MDHHS also investigate other testing sited that test 500 or more children each year. That data has not yet been provided.
Because of the large increase in third quarter tests for 2015, it remains worthwhile to see if weather/climate data might be unique for the period of July – September 2015. A dry and hot weather pattern would increase the potential for exposure to exterior lead hazards (soil) and hazards related to windows, two of the more frequent historical sources of exposure for children in Grand Rapids.
The Healthy Homes Coalition also raised two additional areas for future consideration. First, the increasingly tight rental market may be resulting in more substandard units being occupied by families with children. A methodology for exploring this possibility needs to be developed. Second, while the stability of the Grand Rapids water system does not lend itself to water as a possible source, there is a lack of data to rule out water. The last time water surveillance was conducted in Grand Rapids was in 2013 when 50 homes served by Grand Rapids water provided samples. This is a small sample size and is three year old data. More robust data would allow for conclusive information about the potential role of Grand Rapids water in lead poisoning trends.
Lastly, the Healthy Homes Coalition suggested that KCHD engage in a qualitative assessment of a small sample of children exposed in 2015 to see if their stories suggest any common themes. The KCHD staff nurse responsible for case management for lead exposed children will be consulted and case review will be considered.
* CDC reference level for childhood lead poisoning.