Groups of people with unique environmental exposures create a place for politics and science to clash. Perhaps the most famous modern example is the long slow march towards government recognition of health problems associated with Agent Orange exposure during the war in Vietnam or, more recently, the debate over environmental factors in Autism.
The unique environmental public health issue for mine and just older generations however may be the exposures of September 11th first responders and clean up crews. Outrage over the lack of government response, foresight and funding for presumed health issues associated with exposure at Ground Zero seems to be a popular news focus, especially as we honor the tenth anniversary of that terrible day.
Over the past decade, most of the millions of dollars spent on helping treat sick Ground Zero workers has been focused on respiratory problems and mental health issues such as post-traumatic stress disorder.
Cancer treatment has been specifically excluded from federal health funding, with officials arguing there has been insufficient evidence to prove any direct link between the toxins present at the site and the disease.
But last week the results of the first large-scale study, published in the Lancet, found that firefighters who were involved on the day of the attacks and in the weeks that followed had a 19% higher risk of contracting cancer.
“People all around us are getting sick and some are tragically dying. For those who are sick with cancer it’s infuriating to see the foot-dragging in making the link between Ground Zero and the disease.”
Patrick Lynch, who heads a New York police officers’ union, said: “On September 11, we rescued you. Now it’s your turn to rescue us – New York city police officers who are sick and dying.”
The study The Guardian piece references is one of three major studies published in The Lancet recently looking at Ground Zero workers and the health effects associated with their work. This particular study looked at the incidence of all cancer types in New York firefighters who served at the World Trade Center site, as compared to a large control group. The study reports,
Compared with the general male population in the USA with a similar demographic mix, the standardised incidence ratios (SIRs) of the cancer incidence in WTC-exposed firefighters was 1·10 (95% CI 0·98—1·25). When compared with non-exposed firefighters, the SIR of cancer incidence in WTC-exposed firefighters was 1·19 (95% CI 0·96—1·47) corrected for possible surveillance bias and 1·32 (1·07—1·62) without correction for surveillance bias. Secondary analyses showed similar effect sizes.
Impressive in the abstract and worthy of outrage from first responders, friends and family who anecdotally are struggling with cancer diagnoses. However, the story isn’t so clear on further inspection. Indeed the data from the abstract above are firefighters who served at Ground Zero as compared to other New York City firefighters who did not serve at Ground Zero. When the firefighters who served at Ground Zero are compared to a random cohort of American males however the SIR is just 1.02. A 2% increase in cancer findings and, more importantly, not statistically significant.
One of the problems, as the great blog The Incidental Economist points out, is that the cancer incidence amongst the control group of New York City firefighters who did not serve at Ground Zero was much lower than expected for men (and women) their age. That makes the SIR larger and statistically significant. However, perhaps a better comparison is against an average cohort of American males and in such a case there is no increase in cancer incidence.
The second of The Lancet studies titled “Mortality among survivors of the Sept 11, 2001, World Trade Center disaster: results from the World Trade Center Health Registry cohort” there is a remarkable finding that
All-cause SMRs were significantly lower than that expected for rescue and recovery participants (SMR 0·45, 95% CI 0·38—0·53) and non-rescue and non-recovery participants (0·61, 0·56—0·66). No significantly increased SMRs for diseases of the respiratory system or heart, or for haematological malignancies were found…In rescue and recovery participants, level of WTC-related exposure was not significantly associated with all-cause mortality (adjusted hazard ratio 1·25, 95% CI 0·56—2·78, for high exposure and 1·03, 0·52—2·06, for intermediate exposure when compared with low exposure).
Rescue and recovery workers who served at Ground Zero have had lower all cause mortality over the past 10 years as compared to a random cohort of Americans.
I’m not saying that there aren’t real and terrible diseases associated or potentially associated with exposures at the World Trade Center site. Because there are.
9-year cumulative incidence of asthma was 27·6% (number at risk: 7027), sinusitis 42·3% (5870), and gastro-oesophageal reflux disease 39·3% (5650).
Those are incredible incidences as compared to expected. Those responders served incredibly that day and in the months that followed and deserve our attention and focus. But, at a minimum, we need further studies looking at specific cancer incidences for those serving at Ground Zero, before we race to condemn the lack of support they’re received for diseases dubiously linked to their incredible service