Public domain image courtesy Wikimedia Commons
A large study of women from both Germany and China has found a link between air
pollution and the formation of lentigenes, with the most pronounced changes seen in the
cheeks of Chinese women older than age 50, according to research published online
in Journal of Investigative Dermatology (Feb. 8, 2016).
While the impact of traffic-related air pollution, including both particulate material and nitrogen dioxide, on lung function and health has been examined extensively, there has not been any previous investigation of the effect nitrogen dioxide has on human skin said lead investigator Dr. Jean Krutmann, of the IUF-Leibniz Research Institute for Environmental Medicine in Dusseldorf, Germany, in a press release. “This is important because environmentally-induced lung and skin aging appear to be closely related,” he said.
The study looked at two populations. The first was 806 Caucasian women who
participated in the SALIA (Study on the influence of Air pollution on Lung function,
Inflammation and Aging) study, with an average age of 73.5 years (ranging from 67 to 80
years), an average daily sun exposure of 2.6 hours, and of whom 20% had a history of
smoking. The second group comprised 743 Han Chinese women with an average age of
59 (ranging from 28 to 70 years), an average daily sun exposure of 3.5 hours, and of
whom 20% had a history of smoking. More of the German women reported using sun
protective cosmetics (61% vs. 4.2%). Mean nitrogen dioxide exposures were
28.8 µg/cubic meter in the German group, and 24.1 µg/cubic meter in the Chinese group.
They found that nitrogen dioxide exposure was significantly associated with the number
of cheek lentigenes in women older than 50 in both populations—a 10 µg/cubic meter
increase in gas concentration was associated with approximately 25% more lentigenes.
“To the best of our knowledge, this is the largest epidemiological study demonstrating a
link between traffic-related air pollution and the formation of lentigenes,” co-investigator
Li Jin, PhD, of Fudan University’s State Key Laboratory of Genetic Engineering and
Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative
Innovation Center for Genetics and Development, School of Life Sciences, Shanghai,
China, and the Fudan-Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China, said
in the release.
Interestingly, there was no correlation between nitrogen dioxide concentration and
number of lentigenes on the hands or forearms. “The findings also strengthen the concept that the pathogenesis of lentigenes might differ depending on the anatomical site,” said Dr. Jin.