In 2013, Margreet completed her PhD on the social and cultural dynamics of adolescent risk behaviour. More specifically, she focused on comparing and explaining (trends in) adolescent substance use and sexual behaviours in more than 25 western countries. For her thesis, she received a cum laude distinction. In her current research, Margreet focuses on explaining trends in adolescent health in Europe and North America since the early 21st century. In particular, she examines sex inequalities in young people's mental health, substance use, sexual behaviour and internet use.

For her research, she is involved in the international Health Behaviour in School-aged Children (HBSC) study and chairs its gender equality focus group. She closely collaborates with WHO Europe in the field of gender disparities in adolescent health and health promotion. In the past, she worked at different universities, including Queen's University (Kingston, Canada), University of California in Berkeley (USA) and University of St Andrews (United Kingdom). Margreet (co)authored 45 publications in internationally peer-reviewed journals (H-index 21).