The UK NDNS data are based on individual weighed records.
7 Data for portion weights were sourced from UK population data and weighed records in 40 74-year-old 40 74-year-old 40 74-year-old
The 4-d diaries have been assessed alongside the gold-standard method of 7-d weighed records (28) and have been shown to produce comparable results.
Lastly, and perhaps most importantly, the sample size was very small (as befitting a pilot study) and some data (e.g., weighed records) were collected from only a subsample of participants.
The FFQ has been validated in an Irish adult population by comparison with seven day weighed records and the use of one biomarker, 24-hour urinary nitrogen [ 17- 19].
The use of estimated diaries in the NDNS rolling programme was partly motivated by the need to reduce participant burden and minimise under-reporting compared with the weighed records that had been used previously.
The first study by Torheim et al.[ 51] compared the validity of the Food Variety Score and Diet Diversity Score calculated from two FFQs (69 and 164 food items) to those from 2-day weighed records.
The relative validity of the MDC method was evaluated in a sample of Malmö residents, 105 women and 101 men, 50 69 years old, using 3 days of weighed records every other month during a year, as a reference method.
Design: In 30 women of reproductive age (18 45 y), we monitored diets monthly for 1 y by using 48-h weighed records to measure intakes of choline, betaine, folate, methionine, riboflavin, and vitamins B-6 and B-12.
If the remaining wood fuel was not sufficient for the next day, extra wood fuel was weighed, recorded, and added to the remaining wood fuel.
