No negative impact of routine use of sunscreens on bone health, finds JAMA study

Sun screens are popularly suggested to prevent skin cancer but they may put the population at risk of vitamin D deficiency, which in turn may lead to secondary hyperparathyroidism, loss of cortical bone and, ultimately, osteoporotic fractures. Lack of evidence on whether multimodal sun protection is associated with reduced bone mineral density (BMD) or increased prevalence of osteoporotic bone fractures.

A population study by Dr Mohsen Afarideh, MD, MPH and team revealed that routine use of sun-protective behaviors among the US adult population was not associated with decreased BMD or increased risk of osteoporotic fracture. Sun protection may be associated with a modest decrease in the prevalence of osteoporotic fractures, possibly owing to risk-averse behaviours.

The findings of the study are published in JAMA Dermatology.

The objective of the study was to investigate the association of sun-protective behaviors with BMD z scores and the prevalence of osteoporotic fractures.

The study was a population-based cross-sectional study that included data from US adults who participated in the 2017 to 2018 cycle of the National Health and Nutrition Examination Survey (NHANES). Data were analyzed between September and November 2020. Definition of sun-protective behaviors (staying in the shade, wearing long sleeves, and sunscreen use), site-specific and total BMD, and osteoporotic fractures (hip, wrist, and spine) in the NHANES data.

The results of the study were

• A total of 3418 adults 20 years and older (average age, 39.5 years; 1612 men and 1806 women who completed the NHANES dermatology questionnaire were included in this study.

• The prevalence of frequent staying in the shade, wearing of long sleeves, and sunscreen use were 31.6% (95% CI, 27.8%-35.7%), 11.8% (95% CI, 10.6%-13.1%), and 26.1% (95% CI, 23.5%-28.8%), respectively.

• The use of individual sun-protective behaviors was not associated with diminished site-specific and total BMD z scores in the multivariate models (estimate, −0.23 , P = .18; −0.08 [−0.27 to 0.12], P = .72; and −0.10, P = .15 )

• Moderate to frequent staying in the shade was associated with reduced prevalence of spine fractures in the multivariate model (odds ratio, 0.19 [95% CI, 0.04-0.86], P = 0.02).

Afarideh, and team concluded that "In this cross-sectional study, routine use of sun-protective behaviors among the US adult population was not associated with decreased BMD or increased risk of osteoporotic fracture. These reassuring findings add to the growing body of evidence on the safety of sun protection, with no considerable negative association with bone health."

Reference: Afarideh M, Sartori-Valinotti JC, Tollefson MM. Association of Sun-Protective Behaviors With Bone Mineral Density and Osteoporotic Bone Fractures in US Adults. JAMA Dermatol. Published online October 27, 2021.

doi:10.1001/jamadermatol.2021.4143