Fig. 6.

The results of facial elasticity assessment in different solar-exposure time subgroups (a), Fitzpatrick type subgroups (b), and skin type subgroups (O: oily; D: dry; N/C: normal/combinative) (c) of young, middle-aged and old participators

χ ² test was performed for comparison with the 0~2 h/d subgroup, ^* P<0.05, ^** P<0.01; comparison with the Fitzpatrick type II subgroup, ^# P<0.05, ^## P<0.01; comparison with the dry subgroup, ^§ P<0.05, ^§§ P<0.01