E Combet1, M E J Lean. 1. Human Nutrition, School of Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow Royal Infirmary, Glasgow, UK.
Abstract
BACKGROUND: Widespread subclinical iodine insufficiency has recently been reported in Europe, based on urinary iodine using World Health Organization/Food and Agriculture Organization criteria, in particular among young women. Although urinary iodine concentration (UIC) is a useful measurement of the iodine status in a population, it does not provide an insight into the habitual iodine intake of this population. This is compounded by the fact that very few iodine-specific food frequency questionnaires (FFQ) have been validated so far. The present study aimed to develop and validate a new, simple, rapid survey tool to assess dietary iodine exposure in females of childbearing age. METHODS: Iodine was measured in a duplicate 24-h urine collection. Iodine intake was measured with duplicate 4-day semi-quantitative food diaries and the FFQ. Correlation, cross-classification and Bland-Altman analyses were used to estimate agreement, bias and the reliability of the method. The triangular (triad) method was used to calculate validity coefficients. RESULTS: Forty-three women, aged 19-49 years, took part in the validation of the 17-items FFQ. Median (interquartile range) UIC was 74 (47-92) μg L(-1) , which is indicative of mild iodine insufficiency. The FFQ showed good agreement with food diaries with respect to classifying iodine intake (82% of subjects were classified in the same or adjacent quartile). The FFQ was moderately correlated with the food diaries (rs = 0.45, P = 0.002) and urinary excretion in μg L(-1) (rs = 0.34, P = 0.025) but not in μg day(-1) (P = 0.316). The validity coefficients were 0.69, 0.66 and 0.52 for the food diaries, FFQ and urinary iodine excretion, respectively. CONCLUSIONS: The FFQ provides a rapid and reliable estimate of dietary iodine exposure to identify those population subgroups at risk of iodine deficiency.
BACKGROUND: Widespread subclinical iodineinsufficiency has recently been reported in Europe, based on urinary iodine using World Health Organization/Food and Agriculture Organization criteria, in particular among young women. Although urinary iodine concentration (UIC) is a useful measurement of the iodine status in a population, it does not provide an insight into the habitual iodine intake of this population. This is compounded by the fact that very few iodine-specific food frequency questionnaires (FFQ) have been validated so far. The present study aimed to develop and validate a new, simple, rapid survey tool to assess dietary iodine exposure in females of childbearing age. METHODS:Iodine was measured in a duplicate 24-h urine collection. Iodine intake was measured with duplicate 4-day semi-quantitative food diaries and the FFQ. Correlation, cross-classification and Bland-Altman analyses were used to estimate agreement, bias and the reliability of the method. The triangular (triad) method was used to calculate validity coefficients. RESULTS: Forty-three women, aged 19-49 years, took part in the validation of the 17-items FFQ. Median (interquartile range) UIC was 74 (47-92) μg L(-1) , which is indicative of mild iodineinsufficiency. The FFQ showed good agreement with food diaries with respect to classifying iodine intake (82% of subjects were classified in the same or adjacent quartile). The FFQ was moderately correlated with the food diaries (rs = 0.45, P = 0.002) and urinary excretion in μg L(-1) (rs = 0.34, P = 0.025) but not in μg day(-1) (P = 0.316). The validity coefficients were 0.69, 0.66 and 0.52 for the food diaries, FFQ and urinary iodine excretion, respectively. CONCLUSIONS: The FFQ provides a rapid and reliable estimate of dietary iodine exposure to identify those population subgroups at risk of iodine deficiency.
Authors: M Del C Valdés Hernández; J Kyle; J Allan; M Allerhand; H Clark; S Muñoz Manieg; N A Royle; A J Gow; A Pattie; J Corley; M E Bastin; J M Starr; J M Wardlaw; I J Deary; E Combet Journal: J Nutr Health Aging Date: 2017 Impact factor: 4.075
Authors: Sarah C Bath; Victor J M Pop; Victoria L Furmidge-Owen; Maarten A C Broeren; Margaret P Rayman Journal: Thyroid Date: 2016-11-18 Impact factor: 6.568