Table 3.
General additive models for time trend of type 1 diabetes mellitus incidence
| Models | Residual deviance | AIC | p valuea |
|---|---|---|---|
| Base model | |||
| Null model | 2,883.4 | ||
| Year† | 1,872.8 | 2,487.6 | <0.000001 |
| Age* | 1,343.2 | 1,960.0 | <0.000001 |
| Age*+Year† | 332.59 | 951.34 | <0.000001 |
| Age*+Year†+Sex* | 315.23 | 935.97 | 0.000031 |
| Age*+Year†+Sex*+Year:Age* | 259.78 | 884.53 | <0.000001 |
| Age*+Year†+Sex*+Year:Age*+Age:Sex* | 239.51 | 868.26 | 0.000040 |
| Base model + geographical regionb, final model | |||
| Null model | 6,396.12 | ||
| Age*+Year†+Sex*+Year:Age*+Age:Sex*+Region*c | 953.7 | 2202.8 | <0.000001 |
| Base model + population density d, final model | |||
| Null model | 6,280.3 | ||
| Age*+Year†+Sex+Year:Age*+Age:Sex*+Area* e | 1,153.1 | 2,407.9 | <0.000001 |
The AIC and p values (a) from the test of relative fit (compared with the best model in previous step) are presented for model selection
aTest of relative fit
bRegion: north, south
c+Year:Region*+Age:Region*
dArea: urban, rural
e+Year:Area*+Year:Sex+Age:Area*+Area:Sex*+Age:Area:Sex*+Year:Area:Sex*
*Significant components (p < 0.05)
†Significant non-linear components (p < 0.05)