1. How did you get my name and address?

The Australian Electoral Commission provides names, addresses, sex, and age group to approved research studies. This is permitted by the Commonwealth Electoral Act 1918. We have not been given any additional information about you. For more information about this, you can visit:

2. If I am in the sunscreen group, will I have to provide my own sunscreen?

We will provide you with sunscreen. More information about the sunscreen we are using is in the brochure.

3. Where will I have to go to give blood samples?

You will be able to go to the blood collection centre that you would attend if your general practitioner ordered a blood test. They will collect a sample and send it to us by courier.

4. Will the study cost me anything?

The study will mainly cost you in time. We estimate that the monthly surveys will take about 5 minutes, and the survey at the beginning about 15 minutes. If you are in the sunscreen group it will take you a couple of minutes each morning to apply sunscreen.

We know that it takes some time, and the cost of transport, to give the blood samples. To partially compensate you for this, we will give you a $50 e-voucher for each sample you return.

5. Why is vitamin D important & how much do I need?

Vitamin D helps to regulate the amount of calcium in your bloodstream. Having enough vitamin D is important for your bone and muscle health. It is possible that vitamin D might influence many other health outcomes, although this is not yet proven.

In Australia, the levels of a chemical called 25 hydroxy vitamin D (25(OH)D) in your blood are used to classify your vitamin D status as follows:

Sufficient vitamin D:   > 50 nmol/L
Mild deficiency:   30 to 49 nmol/L
Moderate deficiency:   12.5 to 29 nmol/L
Severe deficiency:   <12.5 nmol/L


6. What is the ultraviolet index (UVI)

The UVI is a measure used to indicate the intensity of the sun’s ultraviolet rays, particularly those that lead to sunburn. The Cancer Council recommends that when the UVI is 3 or greater, and you are going to be outdoors for more than a few minutes, you should ensure you have applied sunscreen, and that you seek shade, and wear covering clothing, a hat and sunglasses. The Cancer Council now advises that to protect the skin from the sun when you are going about your everyday activities (e.g., walking to the coffee shop) you should apply sunscreen each morning as part of your usual routine, on all days when the UVI is forecast to reach 3 at some time during the day.

The grid below shows the average monthly maximum UVI for selected Australian locations. The shaded cells show months of the year when routine daily sunscreen application is not needed (you should still use sunscreen if you are going to be outside for an extended period).


7. Who are the Sun-D collaborators?

The following people are collaborating on the Sun-D Trial:

Professor David Whiteman: QIMR Berghofer Medical Research Institute
Dr Mary Waterhouse QIMR Berghofer Medical Research Institute
A/Prof Louisa Gordon QIMR Berghofer Medical Research Institute
Dr Gunter Hartel QIMR Berghofer Medical Research Institute
A/Prof Donald McLeod QIMR Berghofer Medical Research Institute
A/Prof Craig Sinclair Cancer Council Victoria
Prof Robyn Lucas Australian National University
Hayley Bennett Melanoma and Skin Cancer Advocacy Network
Tamara Dawson Melanoma and Skin Cancer Advocacy Network


8. What is a randomised controlled trial?

Randomised controlled trials (RCTs) are considered to the best study design to understand the effect of an intervention (e.g., sunscreen) on health (e.g., vitamin D). This is because by randomly assigning people to the sunscreen and control groups, we even out any differences between daily sunscreen users and non-users. That is, the percentage of people who spend lots of time outdoors, or who are regular exercisers, will be the same between the two groups. That means we can be sure that any differences in vitamin D levels that arise between the two groups are due to the sunscreen, and not due to anything else that might influence vitamin D levels.

9. What sunscreen will be used on the Sun-D Trial?

We are using sunscreen that we have purchased from Hamilton (Hamilton Active Family and Hamilton Everyday Face).

Hamilton Active Family ingredients

Active ingredients: Octyl Salicylate 5%, Homosalate 10%, Butyl Methoxydibenzoylmethane 4%, Octocrylene 8%.

Also contains: Phenoxyethanol, Benzoates, Benzyl Alcohol, and Hydroxybenzoates.

Hamilton Everyday Face ingredients

Active ingredients: Octocrylene 3%, Methoxydibenzoylmethane 3%, 4-Methylbenzylidene Camphor 2%, Ethylhexyl Triazone 2%.

Also contains: Phenoxyethanol

10. If I am in the control group, am I allowed to apply sunscreen?

If you are in the control group we will ask you to continue with your usual sun protection behaviour, including sunscreen use. It is fine to apply sunscreen to avoid your skin getting burnt, as you usually would.