A recent study conducted at the Pediatrics Department of “Sapienza” University of Rome determined that low vitamin D status is associated with primary snoring and obstructive sleep apnea in children.
Sleep disordered breathing (SDB) describes a group of conditions that present abnormal respiratory patterns or insufficient ventilation during sleep. Of the several conditions that are included in SDB, primary snoring (PS) and obstructive sleep apnea syndrome (OSAS) are the most common breathing disorders that children face in sleep.
Those with PS exhibit loud breathing during sleep; though, aside from the noise disruption, this condition is not linked with a more serious underlying problem. Whereas, OSAS results from obstruction of the upper airway due to a temporary relaxation of the muscles lining the throat. This condition may be dangerous due to the lack of oxygen reaching tissues, known as hypoxia, during these episodes.
OSAS is a known independent risk factor for future cardiovascular complications, metabolic disorder and hypertension. As a result, early diagnosis and treatment is crucial for the future health of the child.
In both cell and animal studies, researchers have observed that hypoxia activates inflammatory pathways. Researchers theorize that inflammation may be a potential contributing factor behind the increased risk of cardiovascular complications, metabolic disease and hypertension in OSAS patients; though, future research is needed to confirm this.
Due to vitamin D’s anti-inflammatory properties and beneficial effects on muscle, researchers hypothesize that vitamin D may play a role in SDB. No studies to date have evaluated the role of inflammation and vitamin D status in both OSAS and PS. Therefore, researchers recently aimed to determine if a relationship exists between C Reactive Protein (CRP), mean platelet volume (MPV) and vitamin D status in the development of SDB. CRP and MPV are both markers for inflammation, often present in cardiovascular disease and hypertension.
The researchers conducted a case-control study with a total of 137 children: 67 affected by SBD (22 with PS and 45 with OSAS) and 70 healthy controls. All participants received a blood draw, in which their CRP, complete blood count (CBC) and vitamin D levels were measured.
Here is what the researchers found:
- The mean age of children with SDB was 8.49±2.19 years.
- Males were more likely to have SDB than females, 66% vs 34% respectively.
- Those with PS and OSAS had higher MPV compared to healthy controls (p<0.001).
- Vitamin D levels were lower in children with PS (26.21±10.7) and OSAS (20.80±7.57) compared to their healthy counterparts (34.07±11.11 ng/ml; p<0.001).
- MPV levels were linked with platelet count (p<0.001), vitamin D status (p<0.001) and CRP (p<0.01).
- Vitamin D, CRP and platelet count significantly predicted MPV (p<0.0001).
- Platelet count and vitamin D significantly added to the prediction (p<0.05).
The researchers summarized their findings,
“The present study provides evidence of higher MPV and lower vitamin D levels in children with PS as well as in children with OSAS, and supports the underlying inflammation, hence, highlighting the importance of an early diagnosis of this previously considered benign form of SDB.”
The results also presented the researchers with a novel finding regarding PS. Since inflammation and low vitamin D status were also observed in children with PS, the authors of the study hypothesize that these findings indicate a subtle occurrence of hypoxia, and thus, should be treated as mild OSAS.
The study was limited by its small sample size and observational design. Therefore, in order to prove a causal relationship between vitamin D, inflammation and SDB, large scaled randomized controlled trials are needed.
Sturges, M. Is vitamin D associated with primary snoring and obstructive sleep apnea in children? The Vitamin D Council Blog & Newsletter, 2016.