Vitamin D Deficiency

• Cox's Bazar — Cox’s Bāzār, Bangladesh
• BIRDEM General Hospital — Dhaka, Bangladesh

• Yale-New Haven Hospital-Women's Center — New Haven, Connecticut, United States

• Medical University of Graz — Graz, Austria
• Division of Critical Care, Department of Pediatrics, Victoria Hospital — London, Ontario, Canada
• Children's Hospital of Eastern Ontario — Ottawa, Ontario, Canada
• Hospital Guillermo Grant Benavente — Concepción, Chile

• Scheie Eye Institute of the University of Pennsylvania — Philadelphia, Pennsylvania, United States

• Gulcan Ozturk — Istanbul, Turkey (Türkiye)

• University of Colorado — Aurora, Colorado, United States
• University of Pittsburgh — Pittsburgh, Pennsylvania, United States

• Nutrition Institute, Ljubljana — Ljubljana, Slovenia

Not specified

• Bozok University Medical Center — Yozgat, Turkey (Türkiye)

• Human Intervention Studies Unit, Ulster University — Coleraine, Co.Londonderry, United Kingdom