View clinical trials related to Puberty.
Filter by:Background: - Researchers want to collect information on diet, physical activity, and sun exposure in children and young adults. The data can provide information on the effect these factors might have on the development of cancer and other diseases. Information collected only from adults does not accurately measure these factors. To collect more accurate information, both mothers and children will provide information. Study participants will be from Hebei province in northeastern China and Jiangsu province in eastern China. Objectives: - To collect and study diet, activity, and sun exposure data from Chinese adolescents and their mothers. Eligibility: - Adolescents between 15 and 17 years of age from Hebei and Jiangsu provinces in China. - Mothers of the study adolescents. Design: - Participants will answer questions about their diet, physical activity, and time in the sun. - Participants will wear a pedometer to measure activity for 7 days. They will also wear a badge to measure sun exposure for 3 days. - Participants will record their activities and food and drinks consumed for 3 days. Urine samples will be collected for a full day. - Participants will have a grip strength test. On the last day of the study, they will provide blood, saliva, and toenail samples. - A smaller separate group of adolescents will provide saliva samples only and complete a food questionnaire.
By clinical examinations and withdrawing of blood samples from a large number of healthy Danish children, this study will reveal if age of pubertal onset is declining. Furthermore, the extensive normative data will provide detailed insight into normal ranges and individual changes of anthropometrics and hormone levels in healthy children during childhood and adolescence.