TYPE 1 DIABETES CLUSTER INVESTIGATION: 
WESTON, WELLESLEY AND NEWTON

February 7, 2012

Suzanne K. Condon, Associate Commissioner
Director, Bureau of Environmental Health
Massachusetts Department of Public Health

Outline
I.	Introduction to the Bureau of Environmental Health 
II.	Massachusetts Pediatric Diabetes Surveillance
III.	MDPH Investigation of Type 1 Diabetes in Weston, Wellesley, and Newton
IV.	MDPH Investigation - Methods
V.	MDPH Investigation - Results
VI.	MDPH Investigation - Discussion
VII.	MDPH Investigation - Conclusions
VIII.	MDPH Investigation - Recommendations for Next Steps
IX.	Questions
I. Introduction to the Bureau of Environmental Health 
•	Indoor Air Quality Program
•	Community Assessment Program
•	Environmental Epidemiology Program
•	Environmental Toxicology Program
•	Environmental Health Education and Outreach Program
•	Community Sanitation Program
•	Food Protection Program
•	Radiation Control Program
•	Childhood Lead Poisoning and Prevention Program
I. Introduction to the Bureau of Environmental Health
How do we evaluate health?
•	Assess the potential impact of exposure on the population
•	Evaluate disease frequency in the population
•	Investigate possible associations between exposure and disease
II. Massachusetts Pediatric Diabetes Surveillance
•	Funded through the U.S. Centers for Disease Control and Prevention’s Environmental Public Health Tracking program
•	Coupled with pediatric asthma surveillance
•	Previous verification effort resulted in 97% agreement between school reports and child’s medical record
•	Mailed survey to 2100 public and private school nurses/administrative staff 
•	For 2007-2008 and 2008-2009 response rate >99% 
II. Massachusetts Pediatric Diabetes Surveillance
•	Counts are provided by type of diabetes (Type 1, Type 2, Unknown Type), race/ethnicity, grade, gender, and community of residence
•	Prevalence of Type 1 in MA students in grades K-8 (5-14 years of age) is 2.53 per 1,000 students 
•	Nationally, the prevalence of Type 1 among individuals 5-14 year of age is 2.12 per 1,000 (from the SEARCH for Diabetes in Youth study)
II. Massachusetts Pediatric Diabetes Surveillance
Diabetes in K-8 Students for the 2008-2009 School Year in Massachusetts
•	Children with Type 1 diabetes represented 93% of cases (n=1,761)
•	Children with Type 2 diabetes = 6% (n=111)
•	Unknown type was 1% (n=18)
II. Massachusetts Pediatric Diabetes Surveillance
Type 1 Diabetes in K-8 Students for the 2008-2009 School Year in Massachusetts
•	Although the national prevalence is lower than the MA rate, the methods for determining the rates were very different and could account for some of the difference
•	SEARCH estimates are based on a sample of individuals (0-19 years of age) who participate in their study
•	MDPH estimates are based on school health information for all children who attend grades K-8 (approximately 5-14 year olds) in public and private schools in MA
•	The proportion of non-Hispanic whites is higher in MA (76.1%) than in the U.S. (63.7%); non-Hispanic whites have higher prevalence than other groups

III. MDPH Investigation of Type 1 Diabetes in Weston, Wellesley, and Newton
Selected Massachusetts Communities
Image of map of Selected Communities in Massachusetts - Weston, Wellesley, Newton
III. MDPH Investigation of Type 1 Diabetes in Weston, Wellesley, and Newton
•	February 2008, contacted by Ann Marie Kreft
•	Residents concerned that there may be an unusual number of children with type 1 diabetes in Weston, Wellesley and Newton 
•	Concern was particular to the area where three communities are contiguous
•	Additional concerns focused on the possible relationship to environmental exposure opportunities 
IV. MDPH Investigation - Methods
Selected Census Tracts in Weston, Wellesley and Newton Massachusetts 
Image of map of Selected Census Tracts in Weston, Wellesley, Newton
Massachusetts
IV. MDPH Investigation - Methods
Environmental Epidemiologic Questions 
1.	Does the prevalence of type 1 diabetes in these 3 communities or the census tracts of concern differ from the expected prevalence?
2.	Does family history play more of a role in the observed prevalence in the 3 communities or the census tracts of concern than would be expected?
•	Five to ten percent of individuals diagnosed with type 1 diabetes have a family history of diabetes (Source: Juvenile Diabetes Research Foundation)
3.	Does residential history play a role in the observed prevalence?
4.	Does the geographic distribution of residence at diagnosis appear unusual?
5.	If there appears to be an excess, are there some shared exposures?
6.	Is there a grouping of diagnoses in space or time such that it is plausible that a shared common environmental exposure might have contributed to diagnoses?
IV. MDPH Investigation – Methods
Data Sources
•	In 2007-2008 MDPH began collecting diabetes data from school health records.
•	As with pediatric asthma, data are reported by school nurses and/or administrative staff at public and private schools in Massachusetts.
•	Family Educational Rights and Privacy Act of 1974 (20 U.S.C. 1232g)
•	Protects students’ privacy for educational records; cannot be released w/o parental consent
•	Applies to all educational institutions that receive funds from U.S. Dept of Education
•	Applies to entire content of the student’s record
IV. MDPH Investigation – Methods
Data Sources, continued
•	To address FERPA barriers, in 2009-2010, MDPH worked with school nurse leaders in the three communities to coordinate mailings to all parents of children (including those beyond DPH’s routine K-8 surveillance) diagnosed with type 1 diabetes to obtain consent and gather additional information
•	In 2010, MDPH also contacted health care providers to identify all children in the three communities with type 1 diabetes in an effort to capture information about:
•	pre-school age children  
•	those attending private schools outside Weston, Wellesley, and Newton
IV. MDPH Investigation – Methods
Prevalence Estimates and their Interpretation 
•	Prevalence estimates are calculated by dividing the number of children with type 1 diabetes in a community by appropriate population data
•	95% Confidence Intervals (CI) are calculated for each community to measure:
IV. MDPH Investigation – Methods
Consent Form
•	Residential History
•	Family History
•	Insulin dependency
•	Age at diagnosis
V.  MDPH Investigation - Results
Participant Information from Consent Forms 
Figure showing age at diagnosis and gender for participants
V.  MDPH Investigation – National Comparison Results
Prevalence Estimates of Type 1 Diabetes in Children/Adolescents Ages 0-19 Years in Weston, Wellesley and Newton as of December 31, 2009 
	Prevalence1	95% CI	
Newton	1.69-3.62	1.11-4.68	
Wellesley	2.98-3.58	1.93-5.11	
Weston	3.66-4.50	1.95-7.31	
SEARCH	2.00	1.94-2.06	
1 Diagnoses per 1,000 individuals 0-19 years of age
•	No statistically significant difference seen in community prevalence estimates compared to national prevalence.  
•	Lower bound of range represents results from consent forms and upper bound represents results from the provider response.
V.  MDPH Investigation – State Comparison Results
Prevalence Estimates of Type 1 Diabetes in Children/Adolescents 5-14 Years in Weston, Wellesley and Newton as of December 31, 2009 
	Prevalence	95% CI	
Newton	2.27-3.71	1.37-5.27	
Wellesley	2.53-3.44	1.26-5.68	
Weston	3.83-4.45	1.53-8.45	
Statewide	2.53	2.41-2.65	

•	No statistically significant difference seen in community prevalence estimates compared to statewide prevalence.  
•	These data represent a range of prevalence from 3 sources: consent forms, EPHT and provider response.  

V.  MDPH Investigation – Results
Prevalence Estimates of Type 1 Diabetes in Children/Adolescents Ages 0-19 Years in Selected Census Tracts in Weston, Wellesley, and Newton as of December 31, 2009 
 	Census Tract 	Count	Prevalence	95% CI	
Newton	3747	*	*	0.02-6.04	
Newton	3748	*	*	0.02-4.83	
Wellesley	4042.01	*	*	4.03-18.39	
Wellesley	4043.01	*	*	3.86-14.81	
Weston	3672	*	*	2.43-9.31	
 	All 5 Combined	30	4.88	3.29-6.96	
National	SEARCH Study	 	 	
 		4045	2.00	1.94-2.06	
*Due to the small numbers, counts and prevalence estimates are not reported to protect individuals' privacy.

•	Prevalence in 3 census tracts of Weston and Wellesley is statistically significantly higher than national prevalence. 
•	Prevalence in 2 census tracts in Newton is not statistically significantly different from national prevalence. 
V.  MDPH Investigation - Results
Residential and Family History Information from Consent Forms for 3 Communities 
•	85% of children/adolescents diagnosed with type 1 diabetes resided in Weston, Wellesley, and Newton at the time of diagnosis
•	21 of 65 (32%) reported a family history of diabetes
•	Of those 8 individuals with a parent previously diagnosed with type 1 diabetes, 7 are fathers
•	The risk of type 1 diabetes by age 20 in the offspring of fathers with type 1 diabetes is about 3 times the risk in the offspring of mothers with type 1 diabetes.  
V.  MDPH Investigation - Results
Residential and Family History Information from Consent Forms for 5 Census Tracts 
•	87% of children/adolescents diagnosed with type 1 diabetes resided in Weston, Wellesley, and Newton at the time of diagnosis
•	11 of 30 (37%) reported a family history of diabetes
•	2 of 11 have a parent previously diagnosed with type 1 diabetes
V.  MDPH Investigation - Results
Geographic Distribution of Residence  
•	Mapped address information reported on the consent forms using a GIS
•	Current address was mapped for the children/adolescents who reside in one of the three communities 
•	Address at the time of diagnosis was mapped for those individuals who lived in one of the three communities at the time of their diagnosis. 
•	The spatial pattern of address at diagnosis did not reveal any unusual patterns thus far
VI. MDPH Investigation – Discussion
Risk Factors for Diabetes
•	Type 1 diabetes is thought to be autoimmune in nature; for that reason environmental factors are also thought to play a role. Genetic factors and a family history are also thought to play a role in the development of Type 1
•	Type 2 diabetes also has some suggested environmental risk factors including persistent organic pollutants (e.g. PCBs)
•	Recognized risk factors for Type 2 diabetes include family history, obesity, physical inactivity, race/ethnicity and others

VI. MDPH Investigation - Discussion
Potential Environmental Risk Factors Associated with Type 1 Diabetes*
•	Class	•	Specific agent	
•	Viruses	•	Enteroviruses
•	Rubella (congenital)
•	Coxsackie B
•	Rotaviruses	
•	Nutritional	•	Cow’s milk and cow’s milk-based infant formula
•	Gluten
•	Exposure to Bafilomycin A1
•	Nitrates (N-nitroso compounds)
•	Vitamin D Deficiency	
•	Life-style / Other	•	Exposure to b-cell toxins (e.g. the rat poison, Vacor)
•	Smoking (Family members, indoors)
•	Older maternal age
•	Birth order
•	Infant Growth
•	Birth weight
•	Stressful life events	
*Based on Table 2 from Zvi Laron’s Interplay Between Heredity and Environment in the Recent Explosion of Type 1 Childhood Diabetes Mellitus
VI. MDPH Investigation – Discussion
Other Current Areas of Research and Type 1 Diabetes 
•	Exposure to ozone, sulfates, and particulate air pollution
•	One study in California has shown an association between estimates  of exposure to air pollution and type 1 diabetes; authors recommend further research
•	Exposure to persistent organic pollutants
•	Several studies have been conducted each with major limitation (e.g. cross-sectional design unable to report whether diabetes or higher PCB levels came first)
VI. MDPH Investigation - Discussion
Autoimmune Diseases and Environmental Exposures
•	Literature suggests that petroleum distillates (products, such as diesel fuel created from processing crude oil), mercury, silica and chlorinated hydrocarbons may be associated with lupus and other undifferentiated connective tissue diseases
VI. MDPH Investigation – Discussion
The Development of Type 1 Diabetes*
Genetic Predisposition	
	
Immunologic Trigger/Environmental Event	
	
Autoimmune Response	
	
Insulin Release Impaired	
	
Reduction in Beta Cell Mass	
	
Type I Diabetes	
*Adapted from Figure 338-6 in Diabetes Mellitus in Harrison’s Principles of Internal Medicine, 17th Edition (2008)
VII. MDPH Investigation – Conclusions
Prevalence
•	The prevalence in the three communities is not statistically significantly different from the national prevalence estimates (SEARCH) or statewide prevalence estimates
•	Prevalence estimates for three census tracts in Weston and Wellesley (3672, 4042.01, and 4043.01) are statistically significantly higher than the national prevalence estimate. This is not true for the Newton census tracts of 3747 and 3748.
VII. MDPH Investigation - Conclusions
Family History
•	It appears that family history of type 1 diabetes may have played more of a role in the prevalence of type 1 diabetes in Weston, Wellesley, and Newton as well as in the five census tracts, than in the general population
•	5-10% of individuals with type 1 diabetes are expected to have a family history
•	32% reported family history in the 3 communities 
•	37% reported family history in the 5 census tracts
VII. MDPH Investigation - Conclusions
Residential History
•	85% of the children/adolescents resided in Weston, Wellesley or Newton at the time of their diagnosis. Within the five census tracts in Weston and Wellesley, 87% resided in their census tract at the time of their diagnosis.
VIII. MDPH Investigation - Recommendations for Next Steps
•	Complete the review of environmental sites in the three census tracts in Wellesley and Weston (3672, 4042.01, and 4043.01) 
•	Particular attention will be paid to any patterns that may emerge suggesting that children who may already be at higher risk of developing type 1 diabetes share more common factors including opportunities for environmental exposure(s).
•	Evaluate statewide variability in the prevalence of type 1 diabetes using EPHT data (for grades K – 8) to identify areas with greater than and less than expected prevalence. 
•	The findings from this report coupled with the findings from the environmental site reviews will direct further follow-up investigative efforts. 
IX. Questions?