Cancer incidence among population utilizing geothermal hot water: A census‐based cohort study

Abstract

The aim of the study was to assess whether utilization of geothermal hot-water is associated with risk of cancer. The cohort from census was followed from 1981 to 2010 in nation-wide death and cancer registries. The moving apart of AmericanEurasian tectonic plates, observed in Iceland, results in high volcanic activity. The definition of the study populations was based on geological information. The target population was inhabitants of communities located on bedrock younger than 3.3 million years, utilizing hot-water supply generated from geothermal wells since 1972. The two reference populations were inhabitants of communities without this hot-water supply located on areas with less volcanic/geothermal activity, and bedrock older than 3.3 million years. Hazard ratio (HR), and 95% confidence intervals (CI) were adjusted for age, gender, education, housing, reproductive factors and smoking. HR in the geothermal hot-water supply areas for all cancer was 1.15 (95% CI 1.05-1.25) as compared with nongeothermal areas. The HR for breast cancer was 1.40 (1.12-1.75), prostate cancer 1.61 (1.29-2.00), kidney cancer 1.64 (1.11-2.41), lymphatic and haematopoietic tissue cancers 1.45 (1.08-1.95), and for basal cell carcinoma (BCC) of the skin 1.46 (1.16-1.82). Positive exposure-response relations were observed between the risk of these cancers and the degree of volcanic/geothermal activity in the reference areas. Increased incidence of all cancers, breast, prostate, kidney cancer and BCC of the skin was found among the population utilizing geothermal hot-water for decades. More precise information on exposure is needed in future studies.

Hydrogen sulfide and traffic-related air pollutants in association with increased mortality: a case-crossover study in Reykjavik, Iceland

“…In a recent Icelandic long-term follow-up study among residents of geothermal areas who had been using the hot geothermal water for space heating, washing and bathing (not as drinking water), increased mortality was found for several cancer types, including non-Hodgkin's lymphoma, breast, prostate and kidney cancers, as well as influenza and suicide. 34 This study had a different approach, as compared to the present one, as it mainly aimed to confirm previously found increased cancer incidence; 35 36 however, the population was evidently exposed to low level H 2 S.…”

Association of Cancer Incidence and Duration of Residence in Geothermal Heating Area in Iceland: An Extended Follow-Up

“…The characteristics of the populations have been described in previous studies [ 15 , 16 , 20 ]. Briefly, eligible participants were people aged 5–64 years.…”

“…The authors conclude that increased risk of all cancers and for several tissue-specific types of cancer was a likely consequence of non-anthropogenic environmental pollution, and different cancer-specific carcinogens and mechanisms may be responsible for the higher incidence of certain tumour types among residents in the volcanic area [ 17 ]. In two Icelandic studies [ 15 , 16 ] a higher risk of non-Hodgkin’s lymphoma (NHL), breast cancer, prostate cancer, and basal cell carcinoma (BCC) of the skin were found. The same pattern emerged in both these studies.…”

“…The same pattern emerged in both these studies. The authors advocated the measurement and detection of possible carcinogens in the gas emissions in the geothermal areas and in the geothermal water used for space heating, washing and bathing [ 15 , 16 ].…”

The influence of the environment on the development of thyroid tumors: a new appraisal

“…Positive exposure-response relations were observed between the risk of cancers and the degree of volcanic/ geothermal activity in the reference areas. Increased incidence of all types of cancers was found in populations using geothermal hot water for decades (Kristbjornsdottir & Rafnsson 2013).…”