Drinking water source and mortality in US cities

Area of Science:

• Environmental epidemiology
• Public health
• Cancer research

Background:

• Previous studies suggested a link between drinking water sources and cancer risk.
• Geographical variations in cancer mortality and water supply types require further investigation.

Purpose of the Study:

• To investigate the association between surface drinking water supplies and all-cancer mortality in large US cities.
• To determine if the association between surface water and cancer mortality is statistically significant and consistent with prior research.

Main Methods:

• Analysis of cancer mortality data for 473 large US cities.
• Comparison of mortality risks between cities with 100% surface water and 100% groundwater supplies.
• Replication of findings within 11 independent geographical regions.

Main Results:

• A statistically significant, albeit slight (approximately 2%), excess risk of all-cancer mortality was observed in relation to surface drinking water supplies.
• The association was consistent across different regions, supporting the initial findings.
• The data suggest the observed association may be specific to cancer mortality.

Conclusions:

• Surface drinking water is associated with a small but statistically significant increase in overall cancer mortality.
• This association warrants further investigation, particularly for specific cancer types previously linked to surface water contaminants.
• Public health strategies may need to consider drinking water source as a factor in cancer prevention efforts.