Towards the end of the baseline assessment period (April 2009-September 2010), the UK Biobank started collecting detailed dietary intake measures using a web-based self-administered 24 h dietary assessment, the Oxford WebQ. The Oxford WebQ was completed by 70,724 participants attending their baseline assessment. Additionally, between 2011 and 2012 all participants with valid email addresses (n = 331,013) were invited to complete the Oxford WebQ on four separate occasions. This was done every 3–4 months on variable days to maximise the coverage by season and day of the week (cycle 1: February 2011 to April 2011; cycle 2: June 2011 to September 2011; cycle 3: October 2011 to December 2011; cycle 4: April 2012 to June 2012). Approximately 53% of the participants (n = 176,012) who were contacted by email completed at least one assessment, with a total of 211,050 participants completing at least one dietary assessment either online or at the baseline assessment [6 (link)].
The Oxford WebQ collects information on foods and beverages consumed over the previous day. Participants were presented with a list of up to 206 foods and 32 beverages commonly consumed in the UK and selected the number of portions consumed from each food. This food list was constructed using information from the UK National Diet and Nutrition Survey (NDNS) as well as a pilot study [5 (link)]. At the start of the questionnaire, participants indicated whether their diet over the previous day was typical and if they were following a special diet. Descriptions and help sections were used to help estimating portion sizes of foods (e.g. slices, cups, servings) and participants were asked to report ingredients of composite dishes separately. Total energy and nutrient intakes were generated by multiplying the number of portions consumed by the set quantity of each food portion size and its nutrient composition obtained from the UK Nutrient Databank Food Composition Tables (FCT) from survey year 6, (2012–2013 and 2013–2014) [9 –11 ]. Dietary fibre was calculated using the Englyst method [12 ], which includes non-starch polysaccharides but not lignin and resistant starches.
The Oxford WebQ collects information on foods and beverages consumed over the previous day. Participants were presented with a list of up to 206 foods and 32 beverages commonly consumed in the UK and selected the number of portions consumed from each food. This food list was constructed using information from the UK National Diet and Nutrition Survey (NDNS) as well as a pilot study [5 (link)]. At the start of the questionnaire, participants indicated whether their diet over the previous day was typical and if they were following a special diet. Descriptions and help sections were used to help estimating portion sizes of foods (e.g. slices, cups, servings) and participants were asked to report ingredients of composite dishes separately. Total energy and nutrient intakes were generated by multiplying the number of portions consumed by the set quantity of each food portion size and its nutrient composition obtained from the UK Nutrient Databank Food Composition Tables (FCT) from survey year 6, (2012–2013 and 2013–2014) [9 –11 ]. Dietary fibre was calculated using the Englyst method [12 ], which includes non-starch polysaccharides but not lignin and resistant starches.
Free full text: Click here
