Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort

This review article discusses the gut microbiota and vitamin D as an emerging and vital axis influencing immune aging and age-related diseases. It highlights the dual role of gut microbiota in shaping host immunity and regulating vitamin D metabolism, alongside the significant immunomodulatory potential of vitamin D in maintaining intestinal homeostasis and barrier integrity. The findings suggest that vitamin D deficiency and gut dysbiosis accelerate immunosenescence and inflammageing, contributing to unhealthy aging and increased risk of age-related diseases.

This study suggests that 820,000 deaths per year in the United States and Europe and an increased incidence of breast cancer, colorectal cancer, hypertension, cardiovascular disease, metabolic syndrome, multiple sclerosis, Alzheimer's disease, autism, asthma, type 1 diabetes, and myopia could be attributed to insufficient sun exposure.

This review article, assembled by a team of UV experts, indicates that UV exposure may support multiple internal systems linked to a longer healthspan, including immune regulation, cardiovascular health, metabolic balance, and neuro-endocrine function. UV exposure activates complex neuro-immune-endocrine pathways through the skin that influence systemic physiology. These effects include lowering blood pressure via nitric oxide release, modulating inflammatory and immune responses, supporting metabolic processes related to weight, glucose homeostasis, and adipose tissue function, and influencing hormonal and reproductive pathways. Large cohort studies also associate higher lifetime sunlight exposure with reduced all-cause and cardiovascular mortality, suggesting that sunlight-induced UV signaling may contribute to enhanced longevity and reduced risk of cardiometabolic and inflammatory diseases.