Ultraviolet radiation adversely affects hormonal balance in postmenopausal women

Postmenopausal women with exposure to ultraviolet radiation (UVR) appear to have lower oestrogen and higher gonadotropin levels, an imbalance associated with osteoporosis, lung function decline, and other adverse health effects, a study has found.

Researchers looked at 580 postmenopausal women from six European countries and estimated average UVR exposure 1 month before blood sampling based on personal sun behaviour and ambient levels. The collected samples were assayed for hormone concentrations.

The median daily UVR exposure during the previous month was 55.1 J/m². The average 1-month exposure to UVR correlated with diminished levels of 17β-oestradiol (–15.6 pmol/L, 95 percent confidence interval [CI], –27.69 to –3.51) and estrone (–13.36 pmol/L, 95 percent CI, –26.04 to –0.68), as well as an increase in concentrations of follicle stimulating hormone (9.34 IU/L, 95 percent CI, 2.91–15.77) and luteinizing hormone (13.86 IU/daL, 95 percent CI, 2.48–25.25).

Results of analyses with other exposure windows of 1 week and 3 months were similar, although with somewhat lower effect sizes. Meanwhile, exploring the direct association between dietary intake of vitamin D and hormones did not yield any statistically significant results.

Stratified analyses showed stronger associations for exposure during the sun-rich months and very similar results for white skin complexion versus the entire study population, whereas no statistically significant results could be seen for nonwhite skin complexion.

The findings suggest that limiting UVR exposure may favourably influence hormone balance and counteract adverse health conditions after menopause. The next step in the study is to consider inclusion of several vitamin metabolites, not only the routinely measured vitamin D3.