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. 2015 May 2;5(4):e007385. doi: 10.1136/bmjopen-2014-007385

Table 2.

Statistical models of Danish drinking water composition and sialolithiasis from 2000 to 2010

Estimate SD T-Value p Value
Calcium model
 Copenhagen region (east Zealand) 12.71 5.07 −1.40 0.165
 Western Zealand region 16.09 4.84 3.32 0.001
 North West Denmark region −5.77 5.40 −1.07 0.289
 South West Denmark region 0.11 4.12 0.03 0.979
 Mean age −1.43 0.73 1.96 0.054
 Per cent females 475.77 261.49 1.82 0.072
 Drinking water calcium 0.22 0.08 2.69 0.009
 Drinking water pH 23.12 13.63 1.70 0.094
Adjusted R2 0.50
Magnesium model
 Copenhagen region (East Zealand) 11.24 5.57 2.02 0.047
 Western Zealand region 11.96 5.89 2.03 0.045
 North West Denmark region −4.41 5.41 −0.82 0.417
 South West Denmark region 1.54 4.08 0.38 0.706
 Mean age −1.63 0.76 −2.14 0.035
 Per cent females 492.66 263.31 1.87 0.065
 Drinking water magnesium 1.84 0.80 2.29 0.024
 Drinking water pH 8.76 11.63 0.75 0.454
  Adjusted R2 0.49
Hydrogen carbonate model
 Copenhagen region (East Zealand) 9.66 5.39 −1.79 0.077
 Western Zealand region 9.16 5.98 1.53 0.130
 North West Denmark region −3.93 5.28 −0.74 0.459
 South West Denmark region −0.55 4.10 −0.13 0.893
 Mean age −1.65 0.74 −2.24 0.028
 Per cent females 419.62 261.11 1.61 0.112
 Drinking water hydrogen carbonate 0.09 0.03 3.06 0.003
 Drinking water pH 17.33 12.08 1.43 0.155
  Adjusted R2 0.51

Estimates, t values, p values and adjusted R2 values for three models relating drinking water calcium, magnesium and hydrogen carbonate levels to the incidence of hospital-admitted sialolithiasis in the years from 2000 to 2010 (ie, number of cases per 100 000 citizens per year) on a municipality level (n=98).