title: Spatial analysis of the relationship between mortality from cardiovascular and cerebrovascular disease and drinking water hardness.
abstract: Previously published scientific papers have reported a negative correlation between drinking water hardness and cardiovascular mortality. Some ecologic and case-control studies suggest the protective effect of calcium and magnesium concentration in drinking water. In this article we present an analysis of this protective relationship in 538 municipalities of Comunidad Valenciana (Spain) from 1991-1998. We used the Spanish version of the Rapid Inquiry Facility (RIF) developed under the European Environment and Health Information System (EUROHEIS) research project. The strategy of analysis used in our study conforms to the exploratory nature of the RIF that is used as a tool to obtain quick and flexible insight into epidemiologic surveillance problems. This article describes the use of the RIF to explore possible associations between disease indicators and environmental factors. We used exposure analysis to assess the effect of both protective factors--calcium and magnesium--on mortality from cerebrovascular (ICD-9 430-438) and ischemic heart (ICD-9 410-414) diseases. This study provides statistical evidence of the relationship between mortality from cardiovascular diseases and hardness of drinking water. This relationship is stronger in cerebrovascular disease than in ischemic heart disease, is more pronounced for women than for men, and is more apparent with magnesium than with calcium concentration levels. Nevertheless, the protective nature of these two factors is not clearly established. Our results suggest the possibility of protectiveness but cannot be claimed as conclusive. The weak effects of these covariates make it difficult to separate them from the influence of socioeconomic and environmental factors. We have also performed disease mapping of standardized mortality ratios to detect clusters of municipalities with high risk. Further standardization by levels of calcium and magnesium in drinking water shows changes in the maps when we remove the effect of these covariates.
authors.affiliation: Departamento d Estadistica i Investigacio Operativa, Universitat de Valencia, Valencia, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Ferrandiz
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Abellan
authors.forename: Virgilio
authors.initials: V
authors.lastname: Gomez-Rubio
authors.forename: Antonio
authors.initials: A
authors.lastname: Lopez-Quilez
authors.forename: Pilar
authors.initials: P
authors.lastname: Sanmartin
authors.forename: Carlos
authors.initials: C
authors.lastname: Abellan
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Martinez-Beneito
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Melchor
authors.forename: Hermelinda
authors.initials: H
authors.lastname: Vanaclocha
authors.forename: Oscar
authors.initials: O
authors.lastname: Zurriaga
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
authors.forename: Jose M
authors.initials: JM
authors.lastname: Gil
authors.forename: Santiago
authors.initials: S
authors.lastname: Perez-Hoyos
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ocana
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002118:Calcium / Q000494:pharmacology*; D002318:Cardiovascular Diseases / Q000401:mortality* / Q000517:prevention & control*; D002561:Cerebrovascular Disorders / Q000401:mortality* / Q000517:prevention & control*; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004781:Environmental Exposure; D016021:Epidemiologic Studies; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D018570:Risk Assessment; D014867:Water / Q000737:chemistry*; D014881:Water Supply
chemical_list: D014867:Water; D008274:Magnesium; D002118:Calcium