a1 Department of Social Medicine, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
a2 Department of Community Based Medicine, University of Bristol, Hampton House, Cotham Hill, Bristol BS6 6JS, UK
This study assesses the stability of dietary patterns obtained using principal components analysis (PCA) through early to mid-childhood. Dietary data were collected from children in the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC). Frequency of consumption of a range of food items was recorded by mothers using self-completion postal questionnaires when their children were 3, 4, 7 and 9 years of age. Dietary patterns were identified using PCA and component scores were calculated at each time-point. In total 6177 children had data available at all four time-points. Three patterns were consistently seen across time: the ‘processed’, ‘traditional’ and ‘health conscious’ patterns. At 3 years an additional ‘snack’ pattern was obtained and at 9 years the ‘health conscious’ pattern was slightly modified (meat products were negatively associated). High correlations were evident for all three scores between each pair of time-points. The widest limits of agreement were seen for all pairings between the 3 and 9 years data, whilst the narrowest were seen between the 4 and 7 years data. A reasonable level of agreement was seen with the categorised component scores from each time-point of data (κ ranging from 0·28 to 0·47). Virtually identical dietary patterns were obtained at the ages of 4 and 7; however, periods of change were apparent between the ages of 3 and 4 and the ages of 7 and 9. It is important to make regular dietary assessments during childhood in order to assess accurately the effects of diet on future health outcomes.
(Received November 05 2007)
(Revised February 25 2008)
(Accepted February 25 2008)
(Online publication April 01 2008)
Abbreviations: ALSPAC, Avon Longitudinal Study of Pregnancy and Childhood; PCA, principal components analysis