Public Health Consultation

Appendix G: Response letter to Senator Clinton's office
Attachment: Respiratory hospitalizations in 6 ZIP Code area near the AES Power Plant.

The following tables contain the results of an analysis by the New York State Department of Health (NYSDOH) which assessed hospitalization rates in the six ZIP Code area near the AES power plant which was first evaluated by Dr. Carpenter. The current NYSDOH analysis was done using the same methodology described in the original NYSDOH report entitled "Respiratory Hospitalizations in Areas Surrounding the AES Greenidge Power Plant, Town of Torrey, Yates County, New York", released in January, 2008.

Findings

  • Chronic bronchitis and COPD (Chronic Obstructive Pulmonary Disease) as well as rates of acute respiratory infections were statistically similar to those of other parts of upstate New York between 1993 and 2000. These are the same outcomes and years that Dr. Carpenter originally evaluated.
  • Asthma rates during this period were 37% lower than expected in this area and this deficit was statistically significant.
  • During the earliest period examined, from 1986-1992 acute respiratory infections and asthma were significantly higher than expected while chronic bronchitis and COPD were significantly lower than expected.
  • In the latest study period examined, 2001-2005, asthma was significantly lower than expected and no respiratory illnesses were significantly higher.
  • For the 20 year time period, acute respiratory infections were about 10% higher than expected while asthma and chronic bronchitis and COPD were about 10% lower than expected. All of these findings were statistically significant. The excess in respiratory infections was due entirely to excesses reported during the first time period.
  • Rates of chronic and acute respiratory infections have changed dramatically over the twenty year study period for both the study area and the 40 county comparison area. This may be due to changes in billing practices and changes in NYSDOH hospitalization data reporting requirements and regulations over the past 20 years which has resulted in apparent variations in the rates of certain hospital admissions over that time period.

Several methodological differences between the two analyses may explain why results differ. As in our original analysis, we used a group of 40 predominantly rural upstate NY counties as our comparison area. This is somewhat different than the comparison area examined by Dr. Carpenter which was based on whether or not a ZIP code had or was near a hazardous waste site (and thus included ZIP codes from downstate (excluding NYC) and Long Island). Also, as noted in our original analysis, we only considered primary diagnosis for the hospitalization in selecting individuals whereas Dr. Carpenter evaluated primary diagnosis and 14 additional secondary diagnosis codes. While neither method should cause substantial bias, the results will not be directly comparable. The NYSDOH report describing the methods used and a detailed account of differences between the two analyses can be found at http://www.nyhealth.gov/environmental/investigations/aes/index.htm

Respiratory hospitalization rates for 6 ZIP codes used in the previous analysis conducted by Dr. Carpenter, compared to rates in 40 rural upstate NY counties. The Standardized Prevalence Ratio (SPR) is the ratio of the observed number of hospitalizations to the expected number based on age adjusted statewide hospitalization rates. The confidence interval represents the range around the SPR that tells us there is a 95% chance that the true result is within this range (similar to the margin of error in a poll). Statistically significant, higher than expected results are highlighted in red, while those that are significantly lower than expected are highlighted in blue. Hospitalization rates shown are per 100,000 persons per year.

Table Key
Symbol Meaning
Statistically Significant Decrease Statistically Significant Decrease
Statistically Significant Increase Statistically Significant Increase
1986 – 1992.
Primary Diagnosis of Hospitalization Observed Number of Cases Expected Number of Cases SPR 95% Confidence Interval Age adjusted Hospitalization Rate in Study Area Hospitalization Rate in Reference Area
Acute respiratory infections* 632 510 1.24 Statistically Significant Increase 1.15 1.34 350.4 279.1
Asthma 410 343 1.20 Statistically Significant Increase 1.08 1.32 234.8 200.6
Chronic bronchitis and COPD NOS* 118 196 0.60 Statistically Significant Decrease 0.50 0.72 61.8 102.6
1993 – 2000.
Primary Diagnosis of Hospitalization Observed Number of Cases Expected Number of Cases SPR 95% Confidence Interval Age adjusted Hospitalization Rate in Study Area Hospitalization Rate in Reference Area
Acute respiratory infections* 217 229 0.95 0.83 1.08 102.7 108.9
Asthma 174 278 0.63 Statistically Significant Decrease 0.54 0.73 87.4 140.1
Chronic bronchitis and COPD NOS* 549 555 0.99 0.91 1.07 246.6 251.0
2001 – 2005.
Primary Diagnosis of Hospitalization Observed Number of Cases Expected Number of Cases SPR 95% Confidence Interval Age adjusted Hospitalization Rate in Study Area Hospitalization Rate in Reference Area
Acute respiratory infections* 82 100 0.82 0.65 1.02 59.1 72.3
Asthma 117 152 0.77 Statistically Significant Decrease 0.64 0.92 92.2 118.4
Chronic bronchitis and COPD NOS* 363 372 0.98 0.88 1.08 259.6 266.5
All years, 1986 - 2005
Primary Diagnosis of Hospitalization Observed Number of Cases Expected Number of Cases SPR 95% Confidence Interval Age adjusted Hospitalization Rate in Study Area Hospitalization Rate in Reference Area
Acute respiratory infections* 931 841 1.11 Statistically Significant Increase 1.04 1.18 176.1 158.8
Asthma 701 775 0.90 Statistically Significant Decrease 0.84 0.97 138.1 155.7
Chronic bronchitis and COPD NOS* 1,030 1,124 0.92 Statistically Significant Decrease 0.86 0.97 185.4 203.3

* Outcomes evaluated in Dr. Carpenter's analysis