Shiseido Co., Ltd., MIRAI Technology Institute, Yokohama, Japan.
Photodermatol Photoimmunol Photomed. 2023 Jul;39(4):364-372. doi: 10.1111/phpp.12865. Epub 2023 Feb 18.
Several epidemiological studies have been conducted to understand the relationship between environmental factors (including chronic sun exposure) and clinical signs of pigmented spots. However, no quantitative analysis has focused on the adverse effects of the detailed features of pigmented spots, including their color intensity, size, and number on the cheek. This study was performed to elucidate the adverse effects of environmental factors on clinical signs of pigmented spots.
We conducted an epidemiological survey of 102 Japanese women in 2 regions of high and low sun exposure (southern and northern regions, respectively). Using image analysis of high-resolution digital facial photographs, individual pigmented spots were quantified according to color, size, and total number on the cheek. Each indicator was then compared between the groups.
For the number of pigmented spots on the cheek, the age-related increase curve showed a large slope in the southern group. For the size of pigmented spots, no significant difference was found between the two groups, and large pigmented spots were observed on the cheek even in the northern group. For the color intensity of the spots, the southern group showed a marked age-related change; among older subjects, the pigmented spots were significantly darker in the southern than northern group.
Our results may indicate that environmental factors, including chronic exposure to sunlight, mainly increase the number of pigmented spots and darkening of these spots. However, the occurrence of large pigmented spots may be related to intrinsic factors represented by heredity rather than environmental factors.
已有多项流行病学研究旨在探讨环境因素（包括慢性日照暴露）与色素斑临床特征之间的关系。然而，目前尚无研究定量分析色素斑的详细特征（包括颜色强度、大小和数量）对面部色素斑的不良影响。本研究旨在阐明环境因素对色素斑临床特征的不良影响。
我们对分别处于日照充足地区（南部地区）和日照较少地区（北部地区）的 102 名日本女性进行了一项流行病学调查。利用高分辨率数字化面部照片的图像分析，根据脸颊上的颜色、大小和总数对每个色素斑进行量化。然后对两组间的各项指标进行比较。
对于脸颊上的色素斑数量，南部组的年龄相关增加曲线斜率较大。对于色素斑大小，两组间无显著差异，即使在日照较少的北部组，脸颊上也可见较大的色素斑。对于色素斑的颜色强度，南部组显示出明显的年龄相关变化；在年龄较大的受试者中，南部组色素斑的颜色明显比北部组深。
我们的结果可能表明，环境因素，包括慢性日光暴露，主要增加色素斑的数量和色素斑的黑化。然而，大色素斑的发生可能与遗传等内在因素有关，而与环境因素无关。
