Association between climate and skin aging: A cross-sectional analysis from three metropolitan cities of India

BACKGROUND AND AIM: Skin aging is driven by a large extent by environmental factors such as air pollution. However, it is unknown if and how climate parameters contribute to skin aging and/or if the association is modified by air pollution. To address the above research gap, we analyzed the association between skin aging traits and ambient temperature (AT), relative humidity (RH), and solar radiation (SLR). METHODS: This study was conducted in three metropolitan Indian cities; Delhi, Mumbai, and Bangalore with 1510 women aged between 20-91 years between May 2018 to Feb 2019. SCINEXA™, a validated visual score was used to measure extrinsic facial skin aging. We used an ordinal multiple logistic regression model for the analysis adjusting for air pollutants (PM2.5 and NO2) and psychological stress each at a time with AT. RESULTS: We here report a positive and significant association between AT, and skin aging parameters- wrinkles under the eyes (OR: 1.10, 95% CI; 1.03, 1.19), hyperpigmentation on the forehead (OR: 1.19, 95% CI; 1.08, 1.31), and dark circles under eye (OR: 1.64, 95% CI; 1.51, 1.78). These skin aging signs also showed a positive and significant association with RH and SLR. The association of skin aging signs with AT was robust after accounting for the confounding effect of PM2.5 and NO2 and psychological stress. CONCLUSIONS: The study shows epidemiological evidence of an association between long-term exposure to high AT, RH, and SLR and skin aging parameters and that it might increase the effect of particulate and traffic-related air pollution on skin aging. KEYWORDS: Skin aging; climate; temperature; air pollution; India