Table 4 Study questionnaire items divided into sections

Demographic characteristics

11 items

When were you born?

- 1940, 1941, 1942…, 1999, 2000.

What is your sex?

- Male, female.

What is your smoking status?

- Nonsmoker, Former smoker, I smoke between 0 and 10 cigarettes a day, I smoke between 10 and 20 cigarettes a day, I smoke between 20 and 30 cigarettes a day, I smoke between 30 and 40 cigarettes a day, I smoke more than 40 cigarettes a day.

How much alcohol do you drink?

- I do not drink alcohol, between 0 and 10 items a week, between 10 and 20 items a week, between 20 and 30 items a week, more than 30 items a week.

Do you exercise regularly?

- Yes, no.

Where do you stay on holidays?

- I go on sun holiday more than 4 weeks a year, between 3 and 4 weeks a year, between 2 and 3 weeks a year, between 1 and 2 weeks a year, less than 1 week a year, I only spend my holidays in Denmark or neighboring countries

How many hours a week do you spend outdoor at leisure?

- More than 40 hours, between 30 and 40 hours, between 20 and 30 hours, between 10 and 20 hours, few hours, no hours

Have you used solarium?

- Yes to a very high extend, yes to a high extend, yes to moderate extend, yes to a low extend, yes to a very low extend, no never

How many hours a week do you spend outdoor at leisure?

- More than 40 hours, between 30 and 40 hours, between 20 and 30 hours, between 10 and 20 hours, few hours, no hours

Have you used solarium?

- Yes to a very high extend, yes to a high extend, yes to moderate extend, yes to a low extend, yes to a very low extend, no never

What is your skin type?

- According to the Fitzpatrick scale [58].

Occupational history

8 items

What is your highest educational level?

- Primary school, vocational school, gymnasium, higher education, other

What is your status as outdoor or indoor worker?

- I predominantly work outdoor, I work equal parts outdoor and indoor, I predominantly work indoor

Do your employer provide avoiding the sun around noon as sun protection at work?

- Yes, no

Do your employer provide long trousers and shirt with sleeves as sun protection at work?

- Yes, no

Do your employer provide a wide brimmed hat or cap (not safety helmet) as sun protection at work?

- Yes, no

Do your employer provide readily available sunscreen as sun protection at work?

- Yes, no

Do your employer provide information on prevention of sunlight exposure at work?

- Yes, no

Is your employer aware of protecting his employees from sunlight during outdoor work in the summer?

- Yes, no

Attitude towards occupational skin cancer risk and use of sun protection

14 items

What do you think of the risk of occupational skin cancer?

- The risk is high, moderate, low, insignificant, I do not think about the risk

Do you think it is important to protect your skin from sunlight during outdoor work in the summer?

- Yes to a high degree, moderate degree, low degree, no

For me use of sun protection at work in the summer is: too hot, work disruptive, too expensive, spoils the pleasure of working outdoor, at risk of being ridiculed, just not possible?

- Strongly agree, agree, neither agree nor disagree, disagree, strongly disagree

Use of long trousers and shirt with sleeves in the summer can reduce my risk of skin cancer!

- Strongly agree, agree, disagree, strongly disagree.

Use of a wide brimmed hat in the summer can reduce risk of skin cancer!

- Strongly agree, agree, disagree, strongly disagree

Use of sunscreen in the summer can reduce risk of skin cancer!

- Strongly agree, agree, disagree or strongly disagree

Avoiding the sun around noon in the summer can reduce risk of skin cancer!

- Strongly agree, agree, disagree, strongly disagree

In your opinion which of the following are significant skin cancer risk factors?

- Sunburn, solarium use, sun holidays, working outdoor, outdoor stay at leisure

Of the following, which is the most significant skin cancer risk factor in your opinion?

- Sunburn, solarium use, sun holidays, working outdoor, outdoor stay at leisure

Use of sun protection in the summer according to ICNRP guidelines

12 items

Do you use long trousers and shirt with sleeves respectively at work, at outdoor leisure in Denmark and on sun holiday to locations with more sun than in Denmark?

- Always, often, rarely, never, I do not spend outdoor leisure in Denmark, I do not go on sun holiday to locations with more sun than in Denmark.

Do you use a wide brimmed hat respectively at work, at outdoor leisure in Denmark and on sun holiday to locations with more sun than in Denmark?

- Always, often, rarely, never, I do not spend outdoor leisure in Denmark, I do not go on sun holiday to locations with more sun than in Denmark.

Do you use sunscreen respectively at work, at outdoor leisure in Denmark and on sun holiday to locations with more sun than in Denmark?

- Always, often, rarely, never, I do not spend outdoor leisure in Denmark, I do not go on sun holiday to locations with more sun than in Denmark.

Do you avoid the sun around noon respectively at work, at outdoor leisure in Denmark and on sun holiday to locations with more sun than in Denmark?

- Always, often, rarely, never, I do not spend outdoor leisure in Denmark, I do not go on sun holiday to locations with more sun than in Denmark.

Health characteristics

2 items

Have you ever had skin or lip cancer?

- Skin cancer, lip cancer, skin and lip cancer, no, do not know.

How often have you experienced a sunburn at work?

- Often, rarely, never