However, this difference reduced over the next 3 years and was gone by age 16. ‘Insulin level of resistance rises dramatically from age 9 to 13 years, falls to the same degree until age 16 in that case. Our study discovered that physical activity reduced this early-teenage peak in insulin resistance but got no effect at age 16,’ research author Brad Metcalf, a senior lecturer in exercise and health at the University of Exeter in England, stated in a university news release. ‘A decrease in this peak could lessen the demand on the cells that produce insulin during this critical period, which may protect them for longer in later life,’ Metcalf said.A comprehensive baseline interview was performed, and individuals had been screened for sexually transmitted infections. Participants prospectively were followed, with telephone interviews in 3 and 6 months and every six months thereafter for the duration of follow-up. Individuals received a $10 present card for every completed follow-up interview. In the baseline and follow-up interviews, we collected extensive information on demographic features and reproductive history. This analysis includes the first 7486 participants who used an IUD, implant, DMPA injection, pills, patch, or ring through the study.