A critical assessment of geographic clusters of breast and lung cancer incidences among residents living near the Tittabawassee and Saginaw Rivers, Michigan, USA

Abstract

Objectives: To assess previously determined geographic clusters of breast and lung cancer incidences among residents living near the Tittabawassee and Saginaw Rivers, Michigan, using a new set of environmental factors.

Materials and methods: Breast and lung cancer data were acquired from the Michigan Department of Community Health, along with point source pollution data from the U.S. Environmental Protection Agency. The datasets were used to determine whether there is a spatial association between disease risk and environmental contamination. GIS and spatial techniques were combined with statistical analysis to investigate local risk of breast and lung cancer.

Results and conclusion: The study suggests that neighborhoods in close proximity to the river were associated with a high risk of breast cancer, while increased risk of lung cancer was detected among neighborhoods in close proximity to point source pollution and major highways. Statistically significant (P </= .001) clusters of cancer incidences were observed among residents living near the rivers. These findings are useful to researchers and governmental agencies for risk assessment, regulation, and control of environmental contamination in the floodplains.

Figure 1

Map showing the location of the study area and point source pollution, grouped by emission release type; major roads; and surface water, including the Tittabawassee and Saginaw Rivers.

Figure 2

Breast cancer incidence rates per 10 000 females and odds ratio illustrating positive association between breast cancer incidences among female residents living near suspected sources of environmental contamination covering the period 1989–2002.

Figure 3

Lung cancer incidence rates per 10,000 people and odds ratio illustrating positive association between lung cancer incidences among residents living near suspected sources of environmental contamination covering the period 1989–2002.

Figure 4

Locations of industrial facilities associated with increased risk of lung cancer identified by Lawson and Waller score test, around which clusters of lung cancer have been detected, as presented in Table 4.

Figure 5

Synthesis of spatial clusters of breast cancer based on odds ratio analysis and Turnbull's method.

Figure 6

Synthesis of spatial clusters of lung cancer based on local Moran's test, odds ratio analysis, Turnbull's method, and Lawson and Waller score test.