Nutrition and growth of primary ciliary dyskinesia patients: a systematic review.

Background
Growth, nutritional status and intake can be crucial for the management and prognosis of chronic lung diseases, including primary ciliary dyskinesia (PCD); yet research in PCD is scarce. In this study, we systematically reviewed the existing literature and summarised the evidence on growth, nutritional status and intake of patients with PCD.Methods
We conducted searches in Medline, Embase, Scopus and PubMed limited to the past 20 years, due to changes in the diagnosis of PCD. Eligible studies included cross-sectional, case-control and prospective studies, and case series with >5 people that reported on the growth, nutritional status or intake of patients with PCD. We performed additional searches through reference list checking and in medRxiv for relevant preprints. The review was registered in PROSPERO (CRD420251065699).Results
50 studies were included in the qualitative synthesis. We observed variability in growth-related outcomes, with some studies reporting reduced z-score for height, body weight or BMI, while others reported no growth differences in patients with PCD. The prevalence of undernutrition ranged from 4 to 11%; underweight ranged from 0 to 50%. Overweight and obesity estimates ranged from 3 to 25%. The prevalence of vitamin D insufficiency was 54%, while deficiency was reported in 18-26% of study participants. Only three studies reported on the nutritional intake of patients with PCD.Discussion
We observed considerable variability in growth-related outcomes and a lack of nutritional intake-related data in patients with PCD. The findings we noted related to malnutrition and vitamin D insufficiency/deficiency are alarming and warrant further investigation.