#729: Cancer Cluster at California School (Also see message # 721)
From Lloyd Morgan
Findings of Cancer at La Quinta Middle School
By Sam Milham and Lloyd Morgan
Introduction
In November 2003, teachers at La Quinta Middle School (LQMS) reported to the school administration what they felt was an abnormally high level of cancers.
We became aware of this when a local newspaper, The Desert Sun, wrote a story about the cancer at the school on February 22, 2004. The story reported there were 11 cancers.
We contacted the teachers who requested our assistance. Working with the teachers, who initially used yearbooks and later room assignment lists, we were able to define the “cohort at risk” to be 137 teachers who ever worked at the school since it opened in 1988. The cohort at risk included age at hire, race and gender information.
Using California Cancer Registry cancer incidence data by age, gender and race we have calculated the expected number of cancers through the end of the current academic year ending in June 2007. Starting with the teachers” age at hire, increasing their age each year we found that the expected number of cancers at LQMS is 6.5. There are now 18 primary cancers in 16 teachers. Assuming no new cancers will be diagnosed the relative risk (the ratio of observed cancers to expected cancers) is 2.8. The possibility that this is due to chance is 1 in 10,000 (p=0.0001).
Such an excessive rate of cancer with so little possibility that it is due to chance is best described as a cancer cluster.
Types of Cancers
There have been 4 cases of melanoma diagnosed at LQMS. The expected number of melanoma is 0.41. The relative risk is 9.8. The possibility that this is due to chance is 1 in 1,250 (p=0.0008).
When we excluded the melanoma cancers, the expected number of non-melanoma cancers decreased to 6.1. There are 14 non-melanoma cancers. This is a relative risk of 2.3 with one possibility in 238 that this is due to chance (p=0.0042).
There are 2 cases of thyroid cancer, 2 cases of uterine cancer and 2 cases of breast cancer. The relative risk of these cancers is 13.3, 9.2 and 1.3, respectively. The thyroid and uterine are well above a “statistically significant” (>95% confidence) increased risk level while the breast cancer is not statistically significant (it is at a 75% confidence level).
The other cancers within this cancer cluster are: colon, pancreas, ovary, larynx, lymphoma, polycythemia, multiple myeloma, and leiomyosarcoma.
Length of Employment at LQMS
We divided the teachers into 3 ranges of employment: less that 3 years, 3 to 14 years and 15 or greater years. The longer a teacher works at LQMS the greater the risk. For teachers who worked less than 3 years, the relative risk was 1.7. This increased to 3.2 for teachers who worked between 3 and 14 years and increase yet further to 3.9 for teachers who worked 15 or more years.
Such a trend is a classic sign that some kind of occupational exposure exists.
LQMS Exposures
Measurements taken by the California Dept. of Health Services (Cal-DHS) of a electricity property colloquially referred to as “dirty power” [Electrical engineers refer to dirty power as “high frequency transients” created whenever the electrical current disturbances.] showed that LQMS has “unusual” levels of dirty power. Measurement were taken with a patented meter we call the Microsurge II meter (MS II). [US Patent 6,914,435 B2 granted to Martin H. Graham, Professor Emeritus, Electrical Engineering, UC Berkeley.] We call the values shown on the MS II meter, “MS II units.” Fifty-one rooms were measured. Thirteen of these rooms had dirty powers levels above the maximum value that the meter can measure (>2,000 MS II units).
An analysis was done among teachers who have ever worked in any of these 13 rooms. A risk, 5.1-fold above the expected number of cancers were found in these teachers. For teachers who ever worked in any of these rooms and who worked at LQMS for more than 10 years, a 7.1-fold risk of cancer above what was expected was found.
An analysis was done examining the cumulative exposure to dirty power over the time the teachers worked at the school. This analysis had 4 categories: teachers who worked at LQMS for less than 3-years, teachers whose cumulative MS II exposure was less than 5,000, teachers whose cumulative MS II exposure was between 5,000 and 10,000 and teachers whose cumulative exposure was greater than 10,000. The relative risk of cancer above what was expected was 1.7, 2.3, 5.0 and 4.2 respectively for these 4 categories.
Our conclusion is that the excess risk of cancer at LQMS depends on the amount of exposure to dirty power electricity.
Town Meeting Presentation
On April 26, 2007 a Town Meeting was held for all interested persons. This presentation can be found at http://www.thedesertsun.com/assets/pdf/J171263427.PDF
Lloyd Morgan