Vitamin D and Sun Exposure: A Community Survey in Australia

Round 1

Reviewer 1 Report

The authors used data from an online survey carried out in Australia of 4824 participants in the summer (January) of 2020 to 1 obain a recent indication of publik knowledge about /attitudes towards vitamin D and sun exposure and their associated factors; 2: examine the association between knowledge /attitudes and sun-related behaviors; and 3: examine the association between knowledge/attitudes and being sunburnt.

I missed the definition and authors' opinion of the optimal time of outdoor activity for the D vitamin synthesis in the different skin types; the role of D vitamin supplementation and recommended D vitamin dosage.

Author Response

Please see the attachement.

Author Response File: Author Response.docx

Reviewer 2 Report

Skin cancer incidence is on the rise and understanding people's views on the harmful effects of the sun as well as the benefits we get from it (vit. D) are important to the prevention of skin cancer. The authors performed a comprehensive survey study to understand people's beliefs related to the sun.  Overall, the study was performed well.  However, I have a couple of points that should be addressed.

(1) Although melanoma is more prevalent in people with fair/medium skin, individuals with darker skin color still do get it and are more likely to die from melanoma.  Therefore, the authors should include the data from the 6% of individuals who identified as having darker/olive/black skin. Further, some studies have reported as many as 95% of black adults as being vitamin D deficient. Thus, data that look at the survey results of darker-skinned individuals would be beneficial to the public.

(2) The authors should revise their introduction and conclusion in which they state that “Current evidence from observational studies and randomized controlled trials suggests that sunscreen use does not influence vitamin D status in real-life settings”. They remark that people who think that sunscreen use decreases vitamin D levels have “incorrect knowledge of current evidence”.  However, several studies have reported that sunscreen use can decrease vitamin D levels (other studies say the opposite).  Even the study that the authors cite included experimental studies in which they showed a decline in vitamin D production.  Further, they noted that none of the studies that tested sunscreen used SPF above 16, whereas most sunscreens people purchase now have higher SPFs.  The authors should clarify this statement to reflect that there is literature on both sides of this issue.  Further, if the survey had data that asked what level sunscreen the participants used, that could be useful information to include (i.e. less than 16 vs. greater than 16).

Author Response

Please see the attachment.

Author Response File: Author Response.docx