Table 2

Relative risk (95% CI) in heart disease mortality for a quadrupling in concentrations of constituents in drinking water (for example, 20 mg/l v 5 mg/l of magnesium) in north west England, 1990–92

  • Results from Poisson regression analyses with expected numbers standardised for age, sex, and Carstairs deprivation quintile. CIs are adjusted with overdispersion parameters (1.6 for acute myocardial infarction and 1.9 for ischaemic heart disease).