| Age groups/year | Cases | Control | ||
| No | Percentage | No | Percentage | |
| 20 - 25 | 56 | 34% | 62 | 37.8% |
| 26 - 30 | 48 | 29.2% | 64 | 39% |
| 31 - 35 | 20 | 12.1% | 30 | 18.2% |
| 36 - 40 | 36 | 21.9% | 8 | 0.048% |
| 41 - 44 | 4 | 0.024% | 0 | 0% |
| Total | 164 | 100% | 164 | 100% |