Reports

Questions and Answers

Why did MDPH attempt to link development disabilities and polychlorinated biphenyl (PCB) contamination data in Berkshire County, MA?
Community concerns related to developmental disabilities among children and possible exposures to polychlorinated biphenyls (PCBs) have been voiced by Housatonic River Area (HRA) residents since the discovery of more widespread PCB contamination in the HRA in the late 1990's. Given the extent of historical contamination in the HRA by PCBs, MDPH/BEH proposed to evaluate available developmental disabilities data and PCB contamination data as one of its tracking projects for the U.S. Centers for Disease Control and Prevention (CDC) Environmental Public Health Tracking (EPHT) initiative.

What is the CDC's Environmental Public Health Tracking (EPHT) initiative?
The CDC's EPHT program aims to explore the feasibility of integrating data on environmental hazards and exposures together with data about diseases that may have environmental risk factors. This cooperative agreement provided the MDPH/BEH with an opportunity to explore one of the long-standing concerns of HRA residents.

What is the EPHT developmental disabilities and PCB exposure project?
The purpose of this tracking project was to evaluate data for developmental disabilities in Berkshire County among children (ages 0-10 years) together with available PCB contaminant data to identify whether certain geographic areas display unusual patterns that may warrant further study or public health follow up.

How were the geographical areas of this project determined?
Dalton, Lanesborough, Lee, Lenox, Pittsfield, Sheffield, Stockbridge, and Great Barrington are the eight communities that comprise the HRA in Berkshire County; an area which has experienced PCB contamination related to the General Electric (GE) facility located in Pittsfield, Massachusetts.

What are developmental disabilities?
Developmental disabilities include a broad group of severe chronic conditions that are due to mental and/or physical impairments. People with developmental disabilities have problems with important life activities such as language, mobility, learning, self-help, and independent living. Developmental disabilities typically begin anytime during early development up to 22 years of age and usually last throughout an individual's lifetime. Information for this project included children (ages 0-10 years) diagnosed with developmental disabilities and reported to the MDPH Early Intervention (EI) Program and/or the Massachusetts Department of Education (MDOE).

What causes developmental disabilities?
Strong evidence suggests that the interaction of genetic, environmental, and social factors interacting in complex ways are important determinants of cognitive development and behavior. Heredity accounts for, at most, about 50% of the variance of cognitive, behavioral, and personality traits among individuals. This information suggests to some that the other 50% of variability could be due in part to environmental and social factors. In addition to PCBs, other toxins including lead, mercury, alcohol, and nicotine have been linked to developmental disabilities (Schettler, 2001).

What is known about PCB exposure and developmental disabilities in children?
Some research has shown that prenatal exposure to PCBs has been associated with deficits in cognitive development in children, especially with respect to memory (Jacobson et al., 1985). Toxicological studies have also demonstrated the effects of PCB exposure through disruption of the thyroid system (Brouwer et al., 1998). Epidemiological evidence suggests that exposure to PCBs can lead to delay and impairment in psychomotor and neurological development (Ribas-Fito et al., 2003; Gladen et al., 1998; Huisman et al., 1995a, 1995b; Walkowiak et al., 2001; Chen et al., 1992). As studies continue to be published there is growing evidence that PCB exposure effects neurodevelopment in infancy and childhood.

Did this project look at specific types of developmental disabilities shown in the scientific literature to be linked to PCB exposure?
Yes, using information from published research, MDPH/BEH identified specific diagnoses that might be associated with PCB exposure during early childhood development. MDPH/BEH wanted to look more closely at children who had these specific developmental disabilities and link residential information with areas of PCB contamination data.

Was the MDPH able to gain access to all data necessary to evaluate developmental disabilities in the Berkshire County area?
No, due to a new federal interpretation of the Family Educational Rights and Privacy Act (FERPA) of 1974 (20 U.S.C. 1232g) by the U.S. Department of Education Family Policy Compliance Office, MDPH/BEH was denied direct access to specific information necessary to identify individual children in the MDOE database. To overcome this barrier, it was necessary to seek active consent from parents of children (ages 3-10 years) with developmental disabilities who received MDOE Individual Education Plan (IEP) services. Unfortunately the overall participation rate for this effort was only 31%, which limited the extent to which statistically meaningful results could be determined.

How was study design modified to address this data gap?
Case specific information (including addresses and some other risk factors for developmental disabilities) for children in the EI Program was able to be evaluated individually (n = 2,113), however these data were limited to children ages 0 to 3 years. Since case specific data was not available for the entire MDOE IEP database (ages 3-10 years), aggregate data was used and analyzed separately for the EI data and the MDOE IEP data and crude period prevalence rates were calculated. These rates were compared to see if the number of children with developmental disability diagnoses in one area of Berkshire County (i.e. HRA) differed from that of another. These prevalence rates were considered crude because it was not possible to control for a number of confounding risk factors for developmental disabilities that could affect these rates.

What conclusions could be drawn from the analysis of individual child addresses and PCB environmental data in this project?
This analysis focused on a case defined subgroup of children in the MDPH EI and MDOE IEP datasets with diagnoses that research suggests may be associated with PCB exposure during early childhood development. Less than 1% (n=4) of the EI children in the case defined subgroup (n=609) had a residential address that matched a PCB soil sampling location. One of these EI children had potential exposure to PCBs in residential soil which was above the DEP residential soil standard of 2 ppm, and potential exposure to above background PCB air levels was identified for two of the other EI children. One MDOE IEP student (from those consenting to participate) of the case defined subgroup (n=116) had a matched address, however exposure for this child was unlikely because residential soil sampling was non-detect for PCBs. In general, results of linkage analyses did not reveal patterns that suggested exposure to PCBs likely played a primary role in the occurrence of developmental disability outcomes and evaluation of all data together did not appear to suggest that PCBs played a primary role in developmental disabilities in any one particular area of Berkshire County or across the study population.

What conclusions could be drawn from aggregate data analysis using crude period prevalence rates?
The EI and MDOE IEP crude period prevalence rates (including 95% confidence intervals) for the case defined subgroup of children showed some statistically significant differences between developmental disability outcomes in cities/towns and census tracts when compared to the HRA and Berkshire County as a whole. To evaluate the potential of environmental factors playing a role, those areas with statistically significantly elevated prevalence rates were evaluated in relation to residential PCB contamination in Berkshire County. Based on this analysis, there were no unusual patterns that would suggest PCBs played a primary role in the occurrence of developmental disability outcomes in any one area of Berkshire County. The majority of elevated prevalence rates were not consistent with areas of residential PCB contamination or with proximity to the GE site.

Which cities/towns and census tracts had elevated crude period prevalence rates?
The EI crude period prevalence rates for individual cities/towns were not statistically significantly different from either the HRA or Berkshire County as a whole. One census tract in Pittsfield (9009) was statistically significantly higher than the HRA and of Berkshire County as a whole. However, based on a review of available information (from the Early Intervention files) as well as environmental data for this census tract and others in close proximity to the GE site, it is unlikely that exposure to PCBs played a primary role in developmental disability diagnoses among children in this census tract. In addition, MDOE IEP crude period prevalence rates showed that Pittsfield, Stockbridge, and Windsor were significantly different from that of Berkshire County and of the HRA. These results suggest that it is unlikely that exposure to PCBs played a major role in the occurrence of developmental disabilities since Pittsfield is the only community of the three that has been significantly impacted by PCB contamination. Case specific data was restricted by FERPA so it was not possible to evaluate other important risk factor information for this portion of the analysis. Additionally, when comparing rates for the HRA to that of Berkshire County as a whole, they are not statistically significantly different.

Based on the results of this EPHT project, will there be any future follow-up?
Future surveillance of developmental disability outcomes can only be meaningfully conducted in Massachusetts and elsewhere with modification to the interpretation of FERPA that would allow access to specific information on children diagnosed with developmental disabilities. If modifications are made, and with adequate funding, the MDPH/BEH can more comprehensively evaluate the role of environmental exposures on developmental disability outcomes in Berkshire County and elsewhere in Massachusetts.

Where can I go for more information and resources related to developmental disabilities?
Information can be obtained from the MDPH Early Intervention (EI) Division and the State Department of Education. Additionally the CDC has online information related to developmental disabilities that can be accessed by www.cdc.gov/ncbddd/index.html.

How can I reduce my family's exposure to PCBs?
You can reduce your family's exposure to PCBs by adhering to advisories regarding PCB-contaminated fish and fish-eating wildlife. Children should be cautioned against playing with old appliances, electrical equipment, or transformers, since they may contain PCBs (www.atsdr.cdc.gov/toxfaqs/tf.asp?id=140&tid=26).

Whom should I contact for more information about this EPHT project?

Massachusetts Department of Public Health
Bureau of Environmental Health
ATTN: Environmental Toxicology Program
250 Washington Street
Boston, MA 02108

Phone #: (617) 624-5757
Hotline #: 1-800-240-4266
Fax #: (617) 624-5777
http://www.mass.gov/dph/


This information is provided by the Environmental Toxicology Program within the Department of Public Health.