Preface by Guest Editors

Abstract

The health of the individual and the population in general is based on the interaction between genetic and environmental factors. Nutrition and physical activity are two environmental factors of major importance that operate throughout the life cycle and influence human development. Adolescence is a critical period for growth and sexual, physical and emotional maturation and development, which creates a great deal of our physical trajectory into and through adulthood. HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) is a multicenter study of European adolescents located in urban settings from 11 cities in 10 different countries. These countries differ in geography, climate, religion and the physical and cultural environment with important differentials in dietary and physical activity and inactivity patterns. To carry out this collaborative study dedication on the part of both scientists and participants was required. As external advisors, we attended the working meetings, and were very impressed with the enthusiasm, hard work and persistence to complete the study on the part of Dr Luis Moreno, the coordinator of the study, and the individual investigators. The scientific meetings of the HELENA project consisted of extended discussions of the data generated by the different investigators, and the development of manuals following the training workshops and pilot studies.