Most occupational and environmental health research has focused on associations between a particular hazard and health outcomes, such as asbestos exposure and lung cancer and respiratory diseases, radiation exposure among uranium miners, or insecticide application and risk of leukemia (Alevanja, Ward, & Reynolds, 2007; Archer, 1981; Frost, Harding, Darnton, McElvenny, & Morgan, 2008). Some hazard surveillance or monitoring data have been collected on potential chemical exposure in work settings (Boiano & Hull, 2001; Froines, Wegman, & Eisen, 1989). Research in the Arctic and subarctic regions has examined associations between environmental contaminants, wild food use, and health effects on indigenous people (Egeland, Feyk, & Middagh, 1998; Muckle, Ayotte, Dewailly, Jacobson, & Jacobson, 2001; Mulvad et al., 1996). No studies have looked at population-level exposures in the U.S. to a variety of hazards and very little hazard surveillance data have been collected on a national level (Froines et al., 1989).
For many occupational and environmental hazards, the effects from long-term exposure are not clearly understood. The actual health effects on an individual posed by any particular occupational or nonoccupational hazard depend on the toxicity of the substance, the dose and duration of exposure, an individual's genetic susceptibility to the effects of the hazard, and other behavioral and environmental influences such as use of tobacco. These hazards can cause a variety of health effects such as mutagenic, carcinogenic, neurologic, and endocrine impairment (Rom & Markowitz, 2006).
Many hazards have multiplicative effects. For example, a study of malignant mesothelioma found that Native American silversmiths routinely used asbestos mats to insulate worktables while making silver jewelry (Driscoll, Mulligan, Schultz, & Candelaria, 1988), which exposed them to a hazard (asbestos) that was seemingly unrelated to the occupational activity (silversmithing). Other studies among American Indian, Alaska Native, and First Nations peoples in Canada have explored the effects of heavy metals, mining dust, and lead on the health of native people (Denham et al., 2005; Patel et al., 2008; Wheatley & Paradis, 1995). Surveying a variety of potential hazards provides baseline data for future examination of multiple simultaneous exposure pathways.
No studies to date have surveyed the variety of occupational and environmental hazards to which American Indian and Alaska Native (AI/AN) people might be exposed. AI/AN people work in many occupations with the potential for exposure to health hazards, from uranium and coal mining and processing and agricultural work among Navajo people (Brugge & Goble, 2002; Dawson & Madsen, 1995; Roscoe, Deddens, Salvan, & Schnorr, 1995) to Alaska Native people who work in the Alaska petroleum or mining industry, but the prevalence of exposure has not previously been quantified. Additionally, AI/AN people are overrepresented among U.S. military veterans ages 18-64 in comparison to the general U.S. population so special relevance exists for exposure to military chemicals for those who are active duty or had prior service in the military (U.S. Census Bureau, 2003).
The Education and Research Towards Health (EARTH) Study is a multicenter study of AI/AN people designed to examine risk and protective factors for chronic diseases. We report here on the prevalence of self-reported exposure to occupational and environmental hazards in a large cohort of AI/AN people living in Alaska and the Southwest U.S. and compare the sociodemographic characteristics of persons who reported hazard exposure to those reporting no exposure. These data can be used to provide a baseline for further focused research on the associations between health and occupational and environmental hazards among AI/AN people.
A detailed description of the study design, survey methods, and measurement
instruments for the EARTH Study is given elsewhere (Slattery et al., 2007). Participants from Alaska (95% Alaska Native and 5% American Indian) were recruited from one urban center and 26 small villages in southwest (Yukon-Kuskokwim Delta, primarily Yupik Eskimo), southeast (Panhandle, primarily Haida, Tlingit, and Tsimshian), and south central (Anchorage area, combination of Alaska Native ethnicities) Alaska. Most participating communities were located off the road system and were accessible only by airplane or seasonal access by snowmobile or boat. Navajo participants from the Southwest U.S. were recruited from 48 communities in northern New Mexico and Arizona.
Methods of recruitment included presentations to tribal groups and health care providers, informational tables with brochures and posters staffed by study personnel at community events or high-traffic locations, house-to-house recruiting, referrals, brochures and flyers in public locations, and public service announcements on local radio and in newspapers. In each community, attempts were made to enroll all eligible residents of the community who met the following criteria: self-identified Alaska Native or American Indian eligible for health care through the Indian Health Service, age >18 years of age, and able to give informed consent. Those who were pregnant or receiving chemotherapy were asked to participate at a later date due to health changes caused by those conditions. Our report considers data collected from 11,326 participants enrolled in the study from March 2004 through October 2007. Enrollment ranged from 2% to 49% (median = 29%) of those eligible for participation in each community. A greater proportion of persons in smaller communities participated in the study. Of the total study participants, only 0.2% (n = 19) did not do the occupational and environmental health questionnaire at all, and 0.5% (n = 55) were missing answers for at least one of the occupational and environmental hazard questions.
EARTH participants completed self- and interviewer-administered questionnaires on demographics, diet, physical activity, lifestyle and cultural practices, environmental exposures, cancer screening practices, medical and reproductive history, and family...