| Declining Sex Ratio in a First Nation Community Constanze A. Mackenzie,1 Ada Lockridge,2 and Margaret Keith3 1Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; 2Aamjiwnaang Environment Committee, Aamjiwnaang, Ontario, Canada; 3Occupational Health Clinics for Ontario Workers Sarnia-Lambton, Pt. Edward, Ontario, Canada Abstract
Members of the Aamjiwnaang First Nation community near Sarnia, Ontario, Canada, voiced concerns that there appeared to be fewer male children in their community in recent years. In response to these concerns, we assessed the sex ratio (proportion of male births) of the Aamjiwnaang First Nation over the period 1984-2003 as part of a community-based participatory research project. The trend in the proportion of male live births of the Aamjiwnaang First Nation has been declining continuously from the early 1990s to 2003, from an apparently stable sex ratio prior to this time. The proportion of male births (m) showed a statistically significant decline over the most recent 10-year period (1994-2003) (m = 0.412, p = 0.008) with the most pronounced decrease observed during the most recent 5 years (1999-2003) (m = 0.348, p = 0.006) . Numerous factors have been associated with a decrease in the proportion of male births in a population, including a number of environmental and occupational chemical exposures. This community is located within the Great Lakes St. Clair River Area of Concern and is situated immediately adjacent to several large petrochemical, polymer, and chemical industrial plants. Although there are several potential factors that could be contributing to the observed decrease in sex ratio of the Aamjiwnaang First Nation, the close proximity of this community to a large aggregation of industries and potential exposures to compounds that may influence sex ratios warrants further assessment into the types of chemical exposures for this population. A community health survey is currently under way to gather more information about the health of the Aamjiwnaang community and to provide additional information about the factors that could be contributing to the observed decrease in the proportion of male births in recent years. Key words: community-based, endocrine disruption, environmental exposure, First Nation, sex ratio. Environ Health Perspect 113: 1295-1298 (2005) . doi:10.1289/ehp.8479 available via http://dx.doi.org/ [Online 17 August 2005]
Address correspondence to C.A.Mackenzie, c/o 171 Kendall St., Point Edward, ON, Canada, N7V 4G6. Telelephone: (519) 337-4627. Fax: (519) 337-9442. E-mail: cmack046@uottawa.ca We thank the Aamjiwnaang Environmental Committee for their interest and assistance. We also thank T. Colborn, M. Gilbertson, and N. Birkett for comments and encouragement, and W. Teel and J. Brophy for facilitating this study. C.M. received funding from the McConnell Foundation, Ecosystem Health Program, Faculty of Medicine, University of Western Ontario. The authors declare they have no competing financial interests. Received 7 July 2005 ; accepted 16 August 2005.
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