The Interaction of Age and Anatomical Region Influenced Skin Biophysical Characteristics of Chinese Women

Figures & data

Table 1 Characteristics of the Subjects

Characteristics	Age Range
	20–29	30–39	40–49	50–64	20–64
Age, mean (SD)	25.4 (3.3)	34.1 (2.8)	44.6 (2.8)	56.6 (4.1)	40.1 (12.4)
Number	47	44	40	47	178
Indoor work, %	100	100	100	100	100
Non-smoker, %	100	100	100	100	100
Moisturizers user, %	95.7	100	87.5	87.2	92.7
Daily sunlight exposure time, %
< 2 h	85.1	95.5	92.5	80.9	88.2
2–6 h	14.9	4.5	7.5	19.1	11.8
>6 h	0	0	0	0	0

Figure 1 Age-related change of skin hydration for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). Hydration values are indicated by solid lines and 95% CIs by shaded area in the line graphs, and are expressed as mean ± 95% CIs in the bar graphs.

Table 2 Influence of Anatomical Regions on the Biophysical Parameters

Biophysical Parameters	Forehead	Cheek	Chin	Forearm
Hydration (a.u.)	42.52 ± 11.96	42.12 ± 11.15	43.49 ± 9.80	33.45 ± 8.32**
TEWL (g/m^2·h)	13.58 ± 4.83	13.40 ± 4.18	14.40 ± 4.97	11.04 ± 3.54**
Sebum (μg/cm^2)	38.7 ± 38.1	29.8 ± 30.1**	42.11 ± 38.0	N/A
pH	5.77 ± 0.40	5.91 ± 0.33**	5.78 ± 0.44	5.73 ± 0.44
Melanin index (a.u.)	184.7 ± 45.5	158.1 ± 48.0**	212.2 ± 46.0**	175.7 ± 37.2
Erythema index (a.u.)	305.1 ± 55.4**	281.0 ± 71.1**	377.6 ± 64.6**	209.1 ± 43.7**
Brightness L* (a.u.)	63.64 ± 2.80	63.79 ± 3.18	59.68 ± 4.04**	64.31 ± 2.63
Redness a* (a.u.)	9.86 ± 1.42**	11.20 ± 256	10.83 ± 2.23	8.09 ± 1.55**
Yellowness b* (a.u.)	14.97 ± 2.25*	13.57 ± 2.81	14.24 ± 2.29^#	13.98 ± 1.98
Individual typological angle ITA (°)	42.3 ± 8.8*	45.3 ± 8.4	33.3 ± 12.0**	45.5 ± 6.9

Notes: The data are expressed as mean ± SD. *p<0.05, **p<0.01 compared with other anatomical regions. ^#p<0.05, compared with cheek.

Figure 2 Age-related change of TEWL for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). TEWL values are indicated by solid lines and 95% CIs by shaded area in the line graphs, and are expressed as mean ± 95% CIs in the bar graphs.

Figure 3 Age-related change of skin sebum content for the forehead (A), cheek (B) and chin (C), and the comparison among the four age groups (D). Sebum values are indicated by solid lines and 95% CIs by shaded area in the line graphs, and are expressed as mean ± 95% CIs in the bar graphs. *p <0.05, **p <0.01.

Figure 4 Age-related change of skin surface pH for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). pH values are indicated by solid lines and 95% CIs by shaded areas, and are expressed as mean ± 95% CIs in the bar graphs. *p <0.05.

Figure 5 Age-related change of skin melanin index for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). MI values are indicated by solid lines and 95% CIs by shaded areas, and are expressed as mean ± 95% CIs in the bar graphs. **p <0.01.

Figure 6 Age-related change of skin erythema index for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). EI values are indicated by solid lines and 95% CIs by shaded area in the line graphs, and are expressed as mean ± 95% CIs in the bar graphs.

Figure 7 Age-related change of skin lightness L* for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). Lightness L* values are indicated by solid lines and 95% CIs by shaded area in the line graphs, and are expressed as mean ± 95% CIs in the bar graphs. *p <0.05, **p <0.01.

Figure 8 Age-related change of skin redness a* for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). Redness a* values are indicated by solid lines and 95% CIs by shaded area in the line graphs, and are expressed as mean ± 95% CIs in the bar graphs. *p <0.05, **p <0.01.

Figure 9 Age-related change of skin yellowness b* for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). Yellowness b* values are indicated by solid lines and 95% CIs by shaded area in the line graphs, and are expressed as mean ± 95% CIs in the bar graphs. *p <0.05, **p <0.01.

Figure 10 Age-related change of skin individual typological angle for the forehead (A), cheek (B), chin (C) and forearm (D), and the comparison among the four age groups (E). ITA values are indicated by solid lines and 95% CIs by shaded area in the line graphs, and are expressed as mean ± 95% CIs in the bar graphs. *p <0.05, **p <0.01.