World Allergy Organization-McMaster University Guidelines for Allergic Disease Prevention (GLAD-P): Vitamin D.
BACKGROUND
The prevalence of allergic diseases is approximately 10 % in infants whose parents and siblings do not have allergic diseases and 20-30 % in those with an allergic first-degree relative. Vitamin D is involved in the regulation of the immune system and it may play a role in the development, severity and course of asthma and other allergic diseases.


OBJECTIVE
The World Allergy Organization (WAO) convened a guideline panel to develop evidence-based recommendations addressing the use of vitamin D in primary prevention of allergic diseases.


METHODS
Our WAO guideline panel identified the most relevant clinical questions and performed a systematic review of randomized controlled trials and non-randomized studies (NRS), specifically cohort and case-control studies, of vitamin D supplementation for the prevention of allergic diseases. We also reviewed the evidence about values and preferences, and resource requirements (up to January 2015, with an update on January 30, 2016). We followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to develop recommendations.


RESULTS
Having reviewed the currently available evidence, the WAO guideline panel found no support for the hypothesis that vitamin D supplementation reduces the risk of developing allergic diseases in children. The WAO guideline panel suggest not using vitamin D in pregnant women, breastfeeding mothers, or healthy term infants as a means of preventing the development of allergic diseases. This recommendation does not apply to those mothers and infants who have other indications for prophylactic or therapeutic use of vitamin D. The panel's recommendations are conditional and supported by very low certainty evidence.


CONCLUSIONS
WAO recommendations about vitamin D supplementation for the prevention of allergic diseases support parents, clinicians and other health care professionals in their decisions whether or not to use vitamin D in preventing allergic diseases in healthy, term infants.
Department of Clinical Epidemiology & Biostatistics, McMaster University Health Sciences Centre, Room 2C16 1280 Main Street West, Hamilton, L8N 4K1 ON Canada.|University of Antioquia, School of Medicine, Medellín, Colombia.
Juan José
0000-0002-9912-0031
JJ
Yepes-Nuñez
Pediatric Hospital Bambino Gesù, Vatican City, Italy.
Alessandro
A
Fiocchi
Department of Pediatrics, Nippon Medical School, Tokyo, Japan.
Ruby
R
Pawankar
Department of Clinical Epidemiology & Biostatistics, McMaster University Health Sciences Centre, Room 2C16 1280 Main Street West, Hamilton, L8N 4K1 ON Canada.|Tecnologico de Monterrey School of Medicine, Monterrey, Mexico.
Carlos A
CA
Cuello-Garcia
Department of Clinical Epidemiology & Biostatistics, McMaster University Health Sciences Centre, Room 2C16 1280 Main Street West, Hamilton, L8N 4K1 ON Canada.
Yuan
Y
Zhang
Department of Clinical Epidemiology & Biostatistics, McMaster University Health Sciences Centre, Room 2C16 1280 Main Street West, Hamilton, L8N 4K1 ON Canada.
Gian Paolo
GP
Morgano
Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Kangmo
K
Ahn
Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates.
Suleiman
S
Al-Hammadi
Faculty of Medicine, University of Toronto, Toronto, ON Canada.
Arnav
A
Agarwal
Faculty of Medicine, University of Toronto, Toronto, ON Canada.
Shreyas
S
Gandhi
Charité Klinik für Pädiatrie, Berlin, Germany.
Kirsten
K
Beyer
Department of Pediatrics, University of North Carolina, Chapel Hill, NC USA.
Wesley
W
Burks
University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy.
Giorgio W
GW
Canonica
Department of Allergy, Clinical Research Center for Allergology and Rheumatology, Sagamihara National Hospital, Kanagawa, Japan.
Motohiro
M
Ebisawa
Department of Pediatrics and Child Health, Aga Khan University Hospital, Nairobi, Kenya.
Rose
R
Kamenwa
Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore.
Bee Wah
BW
Lee
Department of Primary Child Care, Children's Hospital, Chongqing Medical University, Chongqing, China.
Haiqi
H
Li
Department of Immunology, Perth Children's Hospital, Telethon KIDS Institute, School of Paediatrics and Child Health, University of Western Australia, Crawley, Australia.
Susan
S
Prescott
Department of Clinical Epidemiology & Biostatistics, McMaster University Health Sciences Centre, Room 2C16 1280 Main Street West, Hamilton, L8N 4K1 ON Canada.|Department of Family Medicine, McMaster University, Hamilton, ON Canada.
John J
JJ
Riva
Allergy-Immunology Division, Children's Mercy Hospital & University of Missouri - Kansas City School of Medicine, Kansas City, MO USA.
Lanny
L
Rosenwasser
Jaffe Food Allergy Institute, Icahn School of Medicine at Mount Sinai, New York, NY USA.
Hugh
H
Sampson
Food Allergy Research & Education (FARE), McLean, VA USA.
Michael
M
Spigler
Department of Child and Maternal Medicine, University of Milan Medical School at the Melloni Hospital, Milan, Italy.
Luigi
L
Terracciano
Allergology Department, Hospital Infantil Universitario Niño Jesus, Madrid, Spain.
Andrea
A
Vereda
Department of Medicine, McMaster University, Hamilton, ON Canada.
Susan
S
Waserman
Department of Clinical Epidemiology & Biostatistics, McMaster University Health Sciences Centre, Room 2C16 1280 Main Street West, Hamilton, L8N 4K1 ON Canada.|Department of Medicine, McMaster University, Hamilton, ON Canada.
Holger J
HJ
Schünemann
Department of Clinical Epidemiology & Biostatistics, McMaster University Health Sciences Centre, Room 2C16 1280 Main Street West, Hamilton, L8N 4K1 ON Canada.|Department of Medicine, McMaster University, Hamilton, ON Canada.
Jan L
JL
Brożek
Allergic Diseases; GRADE; Practice guidelines; Prevention; Vitamin D