Online Program

Incidence of cancer among population utilizing geothermal hot water: A census based cohort study

Wednesday, November 6, 2013 : 1:20 p.m. - 1:35 p.m.

Vilhjalmur Rafnsson, MD, Department of Preventive Medicine, University of Iceland, Reykjavik, Iceland
Adalbjorg Kristbjornsdottir, PhD, Centre of Public Health Sciences, University of Iceland, Reykjavik, Iceland
Background/Purpose: Residents in high temperature geothermal areas have higher incidence of cancers than others due to increased incidence of non-Hodgkin lymphoma, breast, and pancreas cancers. The aim was to assess whether utilization of geothermal hot water for heating and washing is associated with risk of cancer. Methods: The data source was the census from 1981. Personal identifier of those 5-65 years of age was used in record linkage with nation-wide death and cancer registries. Thus, vital and emigration status was ascertained and cancers cases identified. The exposed population was defined as inhabitants of communities with geothermal hot-water supply generated from geothermal wells since 1972. Reference populations were inhabitants of other communities on areas with different degree of volcanic/geothermal activity. Hazard ratio (HR) and 95% confidence intervals (CI) were estimated in Cox-model. Results: Adjusted HR in the hot-water supply areas for all cancer was 1.11 (95%CI 1.03-1.20) as compared with cold area. The HR for breast cancer was 1.26 (1.04-1.52), prostate cancer 1.36 (1.13-1.64), kidney cancer 1.49 (1.07-2.08), and for basal cell carcinoma (BCC) of the skin 1.38 (1.14-1.68). Positive exposure-response relations were observed between these cancers and the degree of volcanic/geothermal activity in the reference areas. The HRs for single cancer site were never significantly lower than unity. Conclusion: The increase of breast cancer and BCC is consistent with previous findings in high temperature geothermal areas. Data on reproductive factors do not explain the increased risk of breast cancer. More precise information on exposure is needed in further studies.

Learning Areas:

Environmental health sciences
Public health or related education
Public health or related research

Learning Objectives:
Explain the procedure of record linkage based on personal identifier in register studies Identify the most important risk factors for breast cancer in population based studies Discuss the possible risk factors for basal cell carcinoma of the skin Discuss how to design and conduct an eocological study with adjustment for several risk factors

Keyword(s): Breast Cancer, Registry

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am currently professor in Preventive Medicine at the University of Iceland, Iceland, and have several international publications in the field.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.