Cancer mortality and other causes of death in users of geothermal hot water

Abstract

Background. Residents of geothermal areas have increased incidence of non-Hodgkin ' s lymphoma, breast, prostate, and kidney cancers. The aim was to study whether this is also refl ected in cancer mortality among the population using geothermal hot water for space heating, washing, and showering. Methods. The follow-up was from 1981 to 2009. Personal identifi er of those 5 -64 years of age was used in record linkage with nationwide death registry. Thus, vital and emigration status was ascertained. The exposed population was defi ned as inhabitants of communities with district heating generated from geothermal wells since 1972. Reference populations were inhabitants of other areas with different degrees of volcanic/geothermal activity. Hazard ratio (HR) and 95% confi dence intervals (CI) were adjusted for age, gender, education, housing, reproductive factors and smoking habits. Results. Among those using geothermal water, the HR for all causes of death was 0.98 (95% CI 0.91 -1.05) as compared with cold reference area. The HR for breast cancer was 1.53 (1.04 -2.24), prostate cancer 1.74 (1.21 -2.52), kidney cancer 1.78 (1.03 -3.07), and for non-Hodgkin ' s lymphoma 2.01 (1.05 -3.38). HR for infl uenza was 3.36 (1.32 -8.58) and for suicide 1.49 (1.03 -2.17). Conclusion. The signifi cant excess mortality risk of breast and prostate cancers, and non-Hodgkin ' s lymphoma confi rmed the results of similarly designed studies in Iceland on cancer incidence among populations from high-temperature geothermal areas and users of geothermal hot water. The risk is not confi ned to cancers with good prognosis, but also concerns fatal cancers. Further studies are needed on the chemical and physical content of the water and the environment emissions in geothermal areas.

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 communities in geothermal heating areas were all located in the central region of the country where the bedrock is less than 3.3 million years old, and some of these communities were on or near even younger bedrock, less than 0.8 million years old. The two reference populations were also identified by the community codes in the census [ 19 ]; they had not utilised geothermal heating systems as old as 1972 [ 11 ], and age of the bedrock was also taken into consideration [ 20 ]. The first of these two reference populations, called the cold reference area, included residents of communities located in the west and east parts of Iceland where the bedrock is more than 3.3 million years old and up to 15 million years old.…”

“…With the passage of time, it is becoming increasingly difficult to obtain populations in Iceland unexposed to geothermal water, as approximately 90% of all houses and swimming pools are at present heated with geothermal water and 12% of the electricity is generated from geothermal power plants [ 11 ]. The exposed area and reference areas were the same as used in the previous mortality study [ 20 ].…”

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

“…Since 1985, the Public Health Institute of Iceland has collected results from annual surveys on smoking habits among random samples of the population according to gender and postal codes [ 25 ]. The estimation of smoking habits on community and gender level was done according to the same procedure as has been described in previous studies [ 16 , 20 ].…”