Asking People With Psoriasis About Lifestyle and Eating

The self-assessed Simplified Psoriasis Index measures psoriasis severity as a joint score of 3 categories.

Severity; a 3-point scale will measure the severity of skins lesions on 10 body parts. 0=minimal, +/-=noticeable. + =extensive. A 5-point scale ranging from 0=clear to 5=intensely inflamed skin will measure the overall state of psoriasis.

Psychosocial; a 10 point scale ranging from 0=not at all to 10=very much will indicate the extent to which psoriasis is affecting day-to-day life.

Intervention; participants will need to indicate each psoriasis treatment that is being received. 1 point per treatment.

The sa-PSI will generate a total score out of 70. The higher the score, the greater the severity of psoriasis.

This index measures the impact of psoriasis on day-to-day routines as well as on psychological and social fronts. Responses to questions are scored as follows: very much (3 points), a lot (2 points), a little (1 point), not at all/not relevant (0 points).

The DLQI provides a score between 0-30. The score range is interpreted as follows: 0-1 points = no effect at all on the participants life, 2-5 points = small effect on participant's life, 6-10 points = moderate effect on participant's life, 11-20 = very large effect on participant's life and 21-30 = extremely large effect on participant's life.

The Twins United Kingdom (TwinsUK) modified European Prospective Investigation into Cancer Food Frequency Questionnaire (EPIC FFQ) will assess dietary intake.

This FFQ will provide an overview of the consumption of 131- food items over the past 12 months. Each food item will be rated on a 9 point scale as follows: Never or less than once a month, 1-3 times per month, Once a week, 2-4 per week, 5-6 per week, Once a day, 2-3 per day, 4-5 per day and 6+ per day.

Nutrient consumption will be examined using the Intake24 (https://intake24.co.uk/). This is dietary assessment tool in which participants will record their food intake over the past 24 hours. The results obtained from the Intake24 will provide a detailed breakdown of the total calories, macronutrients and micronutrients consumed.

Questions from the Pittsburgh Sleep Quality Index will be used to evaluate sleep quality, latency and duration.

Sleep quality: is measured on a 4-point scale ranging from very bad to very good.

Sleep latency: participants will indicate the number of minutes taken to fall asleep on a weekday and weekend day. The 6-point scale ranges from 0-10 minutes to 60+ minutes.

Sleep duration: participants will indicate the number of hours of actual sleep that are obtained on a weekday/weekend day.

The International Physical Activity Questionnaire (IPAQ) categorises PA into vigorous intensity, moderate intensity and walking. The frequency (number of days/week) and the duration (number of hours) for each PA category will determine the participant's PA level:

Health Enhancing Physical Activity (HEPA)=vigorous intensity physical activity is undertaken on at least 3 days/ week with a minimum of 1500 metabolic equivalent (MET) minutes/week or with 7 or more days of any combination of walking, moderate or vigorous intensity activities with a minimum of 3000 MET minutes/week.

Minimally active (any one of the following)=3 or more days of vigorous activity with at least 20 minutes/day, 5 or more day of moderate intensity or walking at least 30 minutes/day, or 5 or more days of combination of walking, moderate or vigorous intensity activities with a minimum of 600 MET minutes/week.

Inactive=no activity is reported or if some activity is reported but does not meet the above criteria.

The frequency and units of alcohol intake will be examined using the Alcohol Use Disorders Identification Test Consumption (AUDIT-C).

Smoking status will be evaluated as smoker, non-smoker or ex-smoker.

Meal timings will be captured using the Food Timing Questionnaire.

The demographic characteristics assessed include age, gender and ethnicity.

General health will be examined based on the presence of health conditions such as obesity, cardiovascular disease, diabetes etc.

Dietary habits will be evaluated based on the inclusion and exclusion of food items from diet, beliefs around diets and following specific diets as means to improve psoriasis.