Sleep duration as an independent factor associated with vitamin D levels in the EPISONO cohort

Vitamin D deficiency: A forgotten aspect in sleep disorders? A critical update

Over the past few years, there has been a surge in interest regarding the connection between sleep duration and quality, sleep disorders, mainly Obstructive sleep apnoea (OSA) and Vitamin D. There is growing evidence to support a new role of Vitamin D in the maintenance and regulation of optimal sleep. Furthermore, a notable link has been identified between OSA and a decrease in serum Vitamin D levels, which appears to intensify as the severity of sleep apnea worsens. Vitamin D status could also potentially serve as a mediator or provide an explanation for the association between OSA and cardiometabolic morbidity, but the current state of research in this area is inadequate. Studies have indicated that the supplementation of Vitamin D can optimize sleep quality, presenting more proof of the connection between insufficient vitamin D levels and sleep disorders. However, it is unclear whether low serum Vitamin D levels are a contributing factor to OSA development or if OSA predisposes individuals to Vitamin D deficiency. As a result, various studies have endeavored to examine the complex relationship between OSA and Vitamin D deficiency. In children and adolescents, while data is limited, there seems also to be a link between sleep disorders and Vitamin D levels. Therefore, the objective of this review is to provide a comprehensive overview of the current evidence on the association between Vitamin D and sleep disorders in both adults and children.

Obstructive sleep apnea and vitamin D level: Has the dust settled?

Obstructive sleep apnea and vitamin D deficiency are associated with multiple complications with increased morbidity and mortality. However, the relationship between these two entities remains unclear, with clinical studies demonstrating contradictory results. This narrative review aims to present the current evidence and understanding of this relationship and discuss the possible mechanisms linking these two disease entities. Finally, we summarize and propose areas of opportunity for future research.

Sleep Patterns Modify the Association between Vitamin D Status and Coronary Heart Disease: Results from NHANES 2005-2008

BACKGROUND

Although an increased risk of coronary heart disease (CHD) has been reported in individuals with low vitamin D status, this remains controversial. Growing evidence suggests that sleep behaviors may influence vitamin D endocrine functions.

OBJECTIVES

We explored the association between serum 25-hydroxyvitamin D [[25(OH)D] concentrations and CHD and whether sleep behaviors modify this relationship.

METHODS

A cross-sectional analysis of 7511 adults aged ≥20 y in 2005-2008 National Health and Nutrition Examination Survey (NHANES) that included serum 25(OH)D concentrations and provided information on sleep behaviors and history of CHD was performed. Logistic regression models were used to assess the association between serum 25(OH)D concentrations and CHD, whereas stratified analyses and multiplicative interaction tests were used to evaluate the modification effect of overall sleep patterns and each sleep factor on this relationship. The overall sleep patterns integrated 4 sleep behaviors (sleep duration, snoring, insomnia, and daytime sleepiness) in the form of healthy sleep score.

RESULTS

Serum 25(OH)D concentrations were inversely associated with risk of CHD (P < 0.01). Hypovitaminosis D [serum 25(OH)D <50nmol/L] was associated with a 71% increased risk of CHD (OR: 1.71; 95% CI: 1.28, 2.28; P < 0.01) compared with that in participants with sufficient vitamin D [serum 25(OH)D ≥75nmol/L], and the association was more evident and stable among participants with poor sleep patterns (P-interaction < 0.01). Among the individual sleep behaviors, sleep duration had the strongest interaction with 25(OH)D (P-interaction < 0.05). The association between serum 25(OH)D concentrations and risk of CHD was more pronounced in participants with sleep duration <7 h/d or >8 h/d compared with those with sleep duration 7-8 h/d.

CONCLUSIONS

These findings suggest that the influence of lifestyle-related behavioral risk factors, such as sleep behaviors (especially sleep duration), need to be considered when evaluating the association between serum 25(OH)D concentrations and CHD as well as the clinical benefits of vitamin D supplementation.

Nocturnal sleep duration and bone mineral density: a cross-sectional study of the National Health and Nutrition Examination Survey (NHANES) 2007-2014

BACKGROUND

This study aimed to investigate the association between sleep duration and bone mineral density (BMD) and determine whether vitamin D (VD) status influenced the association between sleep duration and BMD.

METHODS

National Health and Nutrition Examination Survey 2007-2014 participants aged ≥ 40 years were included in this study. BMD testing was conducted with dual-energy X-ray absorptiometry examinations. Moreover, all individuals were divided into four groups according to self-reported nocturnal sleep duration (7-8 h; 6 h; < 6 h; and > 8 h). In addition, the differences in BMD between the normal sleep duration group and other groups were calculated using multiple linear regression models.

RESULTS

Overall, the median age of the overall study population was 55.00 years old, with 46.97% of men distributed. Participants sleeping > 8 h/night had lower BMDs than those sleeping 7-8 h/night. Moreover, the association between unhealthy sleep duration (especially > 8 h/night) and low BMD was more pronounced in older individuals, men, postmenopausal women, and subjects with inadequate VD intakes (< 15.00 µg/day) or deficient/insufficient serum 25-hydroxyvitamin D (< 75.00 nmol/L).

CONCLUSIONS

In conclusion, unhealthy sleep duration, especially long sleep duration, was associated with decreased BMD, particularly among individuals aged > 60 years, men, or postmenopausal women. Moreover, VD status might influence the association between sleep duration and BMD, especially in the context of inadequate VD intake or deficient/insufficient serum 25-hydroxyvitamin D levels. However, given the limitations of the present study, further investigation is warranted to confirm this association and to explore potential mechanisms.

Poor sleep quality, vitamin D deficiency and depression in the stroke population: A cohort study

BACKGROUND

Depression is a common psychiatric complication after stroke. However, the relationships among sleep quality, vitamin D status and depression are unclear in stroke patients. The aim of this study was to explore the impact of poor sleep quality and vitamin D status on post-stroke depression (PSD).

METHODS

In the present study, 233 stroke patients completed the one-month follow-up. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI) both at admission and 1 month after stroke. Depressive symptom was measured by the Hamilton Depression Scale (HAMD) at 1 month after stroke. Serum vitamin D levels were measured at admission. Multivariable logistic regression and mediation analysis were used to examine the mediating and moderating effects of sleep quality and vitamin D status on PSD.

RESULTS

The incidence of PSD was higher in patients with poor sleep quality than those with good sleep quality. Vitamin D levels were negatively correlated with HAMD score (r = -0.244, P < 0.001). Prestroke poor sleep quality was associated with an increased risk of PSD in the vitamin D deficiency group after adjustment for potential confounders (OR = 4.047, 95%CI = 1.300-12.600, P = 0.016), while this association was not significant in the vitamin D sufficiency group. In mediation analysis, the relationship between vitamin D deficiency and PSD was mediated by poststroke sleep quality.

LIMITATIONS

Vitamin D levels were measured only at admission.

CONCLUSIONS

The combination of poor sleep quality and vitamin D deficiency is associated with a substantially increased risk of PSD.