Dental plaque index (PLI), at baseline examination in 1985 for the 1390 subjects who were alive and dead from 1996 to 2009
| Alive (n) | Dead (n) | PLI alive | PLI dead | p Value | |
| 1996 | 1371 | 16 | 0.67± (0.47 SD) | 0.84± (0.58 SD) | NS |
| 1998 | 1364 | 23 | 0.66± (0.47 SD) | 0.87± (0.54 SD) | <0.05 |
| 2000 | 1367 | 23 | 0.66± (0.46 SD) | 0.87± (0.54 SD) | <0.05 |
| 2001 | 1359 | 31 | 0.66± (0.47 SD) | 0.91± (0.54 SD) | <0.01 |
| 2009 | 1332 | 58 | 0.66± (0.46 SD) | 0.87± (0.62 SD) | 0.001 |