App Technology to Support Physical Activity and Intake of Vitamins and Minerals After Bariatric Surgery (the PromMera Study): Protocol of a Randomized Controlled Clinical Trial

Stephanie Erika Bonn   ¹ , PhD ;   Mari Hult   ^{1, 2} , MD ;   Kristina Spetz   ^{3, 4} , MSc ;   Marie Löf   ^{5, 6} , PhD ;   Ellen Andersson   ^{3, 4} , MD, PhD ;   Mikael Wiren   ⁷ , MD, PhD ;   Ylva Trolle Lagerros   ^{1, 8} , MD, PhD

¹ Clinical Epidemiology Division, Department of Medicine (Solna), Karolinska Institutet, Stockholm, Sweden

² Division of Upper Abdominal Surgery, Karolinska University Hospital, Stockholm, Sweden

³ Department of Surgery, Linköping University, Norrköping, Sweden

⁴ Department of Biomedical and Clinical Sciences, Linköping University, Norrköping, Sweden

⁵ Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden

⁶ Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden

⁷ Department of Surgery, Ersta Hospital, Stockholm, Sweden

⁸ Center for Obesity, Academic Specialist Center, Stockholm Health Services, Stockholm, Sweden