Objective: To derive dietary patterns using principal components analysis from separate FFQ completed by mothers and their teenagers and to assess associations with nutrient intakes and sociodemographic variables.

Design: Two distinct FFQ were completed by 13-year-olds and their mothers, with some overlap in the foods covered. A combined data set was obtained.

Setting: Avon Longitudinal Study of Parents and Children (ALSPAC), Bristol, UK.

Subjects: Teenagers (n 5334) with adequate dietary data.

Results: Four patterns were obtained using principal components analysis: a 'Traditional/health-conscious' pattern, a 'Processed' pattern, a 'Snacks/sugared drinks' pattern and a 'Vegetarian' pattern. The 'Traditional/health-conscious' pattern was the most nutrient-rich, having high positive correlations with many nutrients. The 'Processed' and 'Snacks/sugared drinks' patterns showed little association with important nutrients but were positively associated with energy, fats and sugars. There were clear gender and sociodemographic differences across the patterns. Lower scores were seen on the 'Traditional/health conscious' and 'Vegetarian' patterns in males and in those with younger and less educated mothers. Higher scores were seen on the 'Traditional/health-conscious' and 'Vegetarian' patterns in girls and in those whose mothers had higher levels of education.

Conclusions: It is important to establish healthy eating patterns by the teenage years. However, this is a time when it is difficult to accurately establish dietary intake from a single source, since teenagers consume increasing amounts of foods outside the home. Further dietary pattern studies should focus on teenagers and the source of dietary data collection merits consideration.