Ambient ultraviolet radiation as a cardioprotective factor: A global and regional analysis.

Background: Ambient ultraviolet radiation (UVR) has been found to have a greater cardioprotective effect than previously believed. This study aimed to quantitatively measure the role of UVR in protecting against the progression of cardiovascular disease (CVD) in general on a global and regional scale.

Methods: Population-level data on UVR, CVD incidence, aging, economic affluence, CVD genetic background (indexed with the Biological State Index, I), obesity prevalence, and urbanization were collected and analysed. The correlation between UVR and CVD was examined using bivariate correlations, partial correlation, and stepwise multiple linear regression. Countries were grouped to investigate regional correlations between UVR and CVD, and Fisher's r-to-z transformation was used to compare correlation coefficients.

Results: UVR showed a significant inverse correlation with CVD incidence rates in bivariate correlation analyses globally ( = - 0.775 and  = - 0.760,  < 0.001), as well as within high-income ( = -0.704,  < 0.001) and low- and middle-income countries (LMIC) ( = -0.851,  < 0.001). These correlations remained significant even after controlling for confounding variables ( = -0.689 to -0.812,  < 0.001). In stepwise regression models, UVR was found to be the most significant predictor of CVD incidence. The inverse correlation between UVR and CVD was stronger in LMICs compared to high-income countries ( = -1.96,  < 0.050).

Conclusions: Low ambient UVR may be a significant risk factor for the progression of CVD worldwide. The protective effect of UVR appears to be stronger in LMICs than in high-income countries, suggesting a greater impact of UVR on CVD prevention in these regions. These findings emphasize the need for further research into the mechanisms underlying the cardioprotective effects of UVR and the development of public health strategies to mitigate CVD risk associated with low UVR exposure.