[DiabEnv] Mass. type 1 diabetes cluster report
John
Last night, the Massachusetts Dept. of Public Health presented the results of a type 1 diabetes cluster investigation in the towns of Newton, Weston, and Wellesley (near Boston). They did indeed find a cluster, in parts of Weston and Wellesley (but not Newton).
Major conclusions:
- The prevalence estimates of type 1 diabetes in children for 3 of the 5 census tracts analyzed were statistically significantly higher than national prevalence estimates. Those higher were located in Weston and Wellesley, while the tracts in Newton were not significantly higher.
- At the community level, the prevalence of type 1 in children was not statistically significantly higher in these communities (i.e., only the smaller-scale census tracts showed a difference, while the larger-scale town estimates did not).
- The prevalence in the three communities is higher in females than males (58% vs 42%), whereas nationally type 1 prevalence in children is about 50-50.
- The prevalence of type 1 diabetes in Massachusetts as a whole is statistically significantly higher than US-wide data.
- A higher percentage of children in the 3 census tracts have family members with type 1 diabetes than is found nationally (32% vs. 5-10% nationally). However, the Mass. study may include more distant relatives than the US study.
- Of those families with parent-child pairs both with type 1 diabetes, 7 of 8 were fathers.
- 85% of the children diagnosed lived in these communities at the time of diagnosis.
- Mapping the locations of current residence and residence at time of diagnosis did not turn up any unusual patterns.
Next steps:
MDPH will complete a review of environmental sites (e.g., leaky underground storage tanks, etc.) in the three census tracts to evaluate potential for exposure to contaminants associated with these sites.
MDPH will evaluate variability in prevalence state-wide to identify areas with greater and less than expected prevalence.
The lead MDPH researcher, Suzanne Condon, was involved in the effort that documented a link between in utero trichloroethylene exposure and childhood leukemia in Woburn (of "A Civil Action" fame). (http://www.ncbi.nlm.nih.gov/pubmed/12685468)
Note that Massacusetts is the only US state that currently tracks diabetes prevalence in children. Beginning in 2007-8, Massachusetts began tracking type 1 and type 2 diabetes prevalence in students grades K-8. (For the cluster study above, the ages were expanded to 0-19).
US prevalence estimates were taken from the SEARCH for diabetes in youth study, which tracks type 1 and type 2 diabetes prevalence and incidence in 10 areas around the US.
Documentation and more details about the cluster study are available here:
and the Mass. diabetes prevalence data is here:
I was able to attend the presentation, and there was a lot of discussion about possible environmental chemical exposures that might have contributed to this cluster. For example, historic use of pesticides, current use of herbicides along railroad tracks, petroleum distillates from leaky underground storage tanks, arsenic in soil, etc. It will be interesting to see if anything turns up with further investigation; so far, efforts have largely focused on counting children with type 1 in these communities (obtaining addresses required parental permission from each family). Other states, however, could implement statewide diabetes surveillance programs similar to Massachusetts', which is based on surveys of school nurses and adminstrators, and provides town or school district level prevalence data on diabetes.
Thanks to Ann Marie Kreft for initiating this investigation!
Sarah