Study shows low death rates for Kelly AFB

SAN ANTONIO -- Results of a newly released mortality study of workers at the former Kelly Air Force Base here show there were significantly fewer deaths from all causes than would have been expected using either U.S. or Texas reference rates for comparison.

The study, published in the Journal of Occupational and Environmental Medicine, investigated the causes of death from among the almost 32,000 civilians who worked for one year or more at Kelly AFB between 1981 and 2000. It was commissioned by Air Force Materiel Command to address concerns about possible health threats to workers from materials used at Kelly AFB.

The Air Force Institute for Environment, Safety, and Occupational Health Risk Analysis at Brooks City-Base, Texas; the San Antonio Metropolitan Health District; the Texas Department of Health; the Agency for Toxic Substances and Disease Registry; and the Amyotrophic Lateral Sclerosis Association monitored the design and progress of the study conducted by Applied Epidemiology Inc., an Amherst, Mass., firm.

"Overall, the findings were consistent with a generally healthy workforce," said Lt. Col. Kenneth Cox, chief of AFIERA's risk assessment division. "Workers are usually healthier than the general population, especially if their jobs include specific physical requirements, and these results showed that the Kelly AFB workers are even healthier than what is usually seen in similar studies involving other occupational groups in America."

The study also looked at specific causes of death identified as concerns by people living near Kelly AFB and in earlier ATSDR public-health assessments. These included cancers of the lung, bladder, liver, kidney, and cervix; leukemia; diabetes; and amyotrophic lateral sclerosis, or ALS, commonly called Lou Gehrig's Disease. Although there were more deaths among Kelly AFB workers from liver cancer, emphysema, and diabetes when compared to U.S. rates, this was not true using specific Texas reference rates.

"This shows that these conditions are, unfortunately, more common in Texas than in other parts of the country, but are not unique to former workers at Kelly AFB," said Dr. Fernando Guerra, director of SAMHD. "This might be due to regional differences in known risk factors such as obesity, smoking, genetic makeup, and sedentary lifestyles."

One finding in the mortality study was that breast cancer occurred more often than expected in both men and women.

Three men died from breast cancer, where one or no deaths would be expected. Male breast cancer is rare and not well understood, though obesity and having a mother or sister with breast cancer seem to go along with an increased risk for the disease. There were 18 breast-cancer deaths among women in the study where only eight would have been expected.

The non-occupational risk factors for developing breast cancer in women are personal or first-degree family history of pre-menopausal breast cancer, early onset of menses, late menopause, and first full-term pregnancy after age 30. Excessive weight gain and too little physical activity seem to play roles as well.

Several occupations, like chemists and beauticians, have been linked with increased breast cancer risk, but these occupations were not found in the study group. Other research has been conducted on potential breast-cancer risks from shift work and workplace exposure to electromagnetic fields, ionizing radiation, and organic solvents.

"Other occupational studies have not been able to clearly identify specific workplace risks for the development of breast cancer in women. It is difficult to evaluate this finding because we didn't have information on common workplace exposure or personal risk factors," explained Cox.

The study did find that 13 of the women who died from breast cancer were Hispanic. Breast cancer is the leading cancer cause of death among Hispanic women.

There were 13 deaths from ALS in this group of workers, which is what would have been expected using either the U.S. or Texas reference rates.

"The openness and cooperative nature of this effort, together with the indispensable support and commitment of ALSA's South Texas chapter and our science advisors, ensured the completion of the most appropriate study to determine whether there were increased numbers of ALS cases at Kelly AFB," said Dr. Lucie Bruijn, ALSA's science director and vice president.

There is a separate study underway to investigate the occurrence of ALS among Kelly AFB workers, living or dead, over the entire history of the base. Although ALS is not always listed as a cause on death certificates, this study is being conducted in close cooperation with the ALS Association and with local South Texas Chapter of ALSA, which has identified 140 people with ALS who either worked at Kelly AFB or lived in surrounding neighborhoods. The results of the ALS-specific study are expected in 2003.

"Overall, these mortality patterns are consistent with a healthy worker population and don't reveal an increased risk of death associated with former employment at Kelly Air Force Base," said Cox. "While encouraging, it's important to remember that there are limitations to mortality studies. For example, death certificates vary considerably in the amount of detail provided by the attending physician. Also, the workforce studied was relatively young and a follow-up look in five or ten years could be useful to see if the findings from this study persist over time."

The SAMHD recently established a Public Center for Environmental Health to monitor the health of the communities surrounding the former base, where many workers still live. The PCEH, in coordination with AFIERA, will follow this group of workers and determine whether additional studies might improve the current understanding of health outcomes and their possible relationship to environmental exposures.