Number of cases and controls (combined) by quartiles of their long term average nitrate concentration and quartiles of their most recent five year average nitrate concentration
| Long term average nitrate quartiles (mg nitrate-N/l) | Recent (five year) average nitrate quartiles (mg nitrate-N/l) | ||||
|---|---|---|---|---|---|
| Q1 (low) | Q2 | Q3 | Q4 (high) | Total | |
| Q1 (low) | 53 | 50 | 4 | 20 | 127 |
| Q2 | 5 | 61 | 174 | 58 | 298 |
| Q3 | 8 | 44 | 4 | 28 | 84 |
| Q4 (high) | 98 | 30 | 3 | 33 | 164 |