Exposure to fine particulate matter associated with senile lentigo in Chinese women: a cross-sectional study

Skin ageing especially senile lentigo directly affects self-esteem. For decades, senile lentigo has been associated with chronic exposure to solar radiation. However, a study conducted recently in Caucasian subjects suggested that exposure to air pollution was significantly correlated with extrinsic skin ageing, in particular senile lentigines.

To investigate the association between fine particulate matter (PM_2.5 ) and skin ageing, particularly senile lentigo and seborrheic keratosis.

The study enrolled 400 Chinese women aged 40-90 years including 210 from the Yanqing county in Beijing (low PM_2.5 exposure group) and 190 from the Xuanwumen in Beijing (high PM_2.5 exposure group). Skin ageing symptoms, particularly senile lentigines and seborrheic keratoses, were clinically assessed using scores of intrinsic and extrinsic skin ageing. An ordinal logistic regression model was used to analyse the effect of PM_2.5 on skin ageing adjusted for factors underlying skin ageing.

In the study population of Xuanwumen, we found that senile lentigo on cheeks and back of hands was 1.48 times and 2.8 times higher, respectively, compared with those from Yanqing county. However, no association was found between PM_2.5 and seborrheic keratosis. We found that other variables such as smoking, second-hand smoking, contact with fossil fuels and skin types were significantly associated with skin ageing.

These results indicate that PM_2.5 was another extrinsic factor promoting skin ageing.