Vitamin D status and its longitudinal association with changes in patterns of sleep among middle-aged urban adults

Serum Vitamin D3 Concentration, Sleep, and Cognitive Impairment among Older Adults in China

BACKGROUND

Cognitive decline in older adults has become one of the critical challenges to global health. This study aims to examine both cross-sectional and longitudinal associations of levels of serum 25-hydroxyvitamin D3 (25(OH)D3) (briefed as VD3) concentration and sleep quality/duration, especially their interactions, with risk of cognitive impairment among older adults in China.

METHODS

We utilized a special subsample of adults aged 65-105 years (individuals = 3412, observations = 4816) from eight provinces in China derived from the 2011/2012 and 2014 waves of the Chinese Longitudinal Healthy Longevity Survey. Cognitive impairment was measured by the Mini-Mental State Examination scale. Sleep quality was classified as good versus fair/poor, and sleep duration was classified into short (<7 h), normal (≥7 but <9 h), and long (≥9 h). The VD3 concentration was divided into three levels: deficiency (VD3 < 25 nmol/L), insufficiency (25 nmol/L ≤ VD3 < 50 nmol/L), and sufficiency (VD3 ≥ 50 nmol/L). A wide set of covariates that include demographics, socioeconomic status, family support, health practice, and health conditions was adjusted for robust findings. Multilevel random intercept logit regression models were used to examine the cross-sectional associations between VD3, sleep, and cognitive impairment, whereas logit regression models were applied to investigate the longitudinal associations.

RESULTS

In the cross-sectional analyses, when all covariates were adjusted, VD3 sufficiency was significantly associated with a 33% lower risk of cognitive impairment compared with VD3 deficiency; good sleep quality was associated with 34% lower odds of cognitive impairment compared with fair/poor sleep quality; sleep hours were not associated with cognitive impairment, although a long sleep duration (≥9 h) was associated with 30% higher odds of being cognitively impaired when baseline health was not controlled. Interaction analyses reveal that VD3 sufficiency could help to additionally reduce the risk of cognitive impairment for good sleep quality and normal sleep hours. In the longitudinal analyses, the association of VD3 sufficiency remains significant, whereas sleep quality and sleep duration were not significant associates.

CONCLUSIONS

Good sleep quality, normal sleep hours, and VD3 sufficiency are positively associated with good cognitive function. VD3 sufficiency could enhance the associations between sleep and cognitive impairment.

The association between nutritional status and sleep quality of Chinese community-dwelling older adults

BACKGROUND

Sleep disorders are a common syndrome and could affect the life quality of the older adults.

AIMS

This study aimed to investigate the association between nutritional status and sleep quality in the Chinese community-dwelling older adults.

METHODS

A total of 2,878 participants ≥ 65 years old from the Yiwu Elderly Cohort were included in the study. Nutritional status was assessed using the Mini Nutritional Assessment Short Form (MNA-SF). Participants were categorized as subjects with malnutrition, at risk of malnutrition or well-nourished based on their MNA-SF score. Pittsburgh Sleep Quality Index (PSQI) was used to identify sleep disorders. PSQI score ≥ 6 was categorized as poor sleep quality.

RESULTS

Among the 2,878 participants (mean age 72.71 ± 5.79 years, 50.3% men), 31.5% (n = 906) were classified as having sleep disorders, and 25.5% were identified as malnutrition or at risk of malnutrition. We found a significantly relationship between nutritional status and sleep quality in older adults, and the results showed well-nourished decreased the risk of sleep disorders (OR = 0.32, 95% CI = 0.13, 0.75). And well-nourished status was significantly associated with less daytime dysfunction, adequate sleep duration, and good subjective sleep quality (all P < 0.05).

CONCLUSION

There was a close association of nutritional status and sleep quality in older adults. We should pay more attention to the nutritional status of older people with sleep problems, as well as the sleep quality of older adults with malnutrition.

Associations of serum 25-hydroxyvitamin D and subjective sleep measures in an Arctic population: Insights from the population-based Tromsø Study

Objective

To investigate the relation between serum 25-hydroxyvitamin D (s-25(OH)D) and subjective sleep measures in an Arctic population (69°N).

Methods

Cross-sectional data was collected from 21,083 individuals (aged ≥40 years) participating in the population based Tromsø Study: Tromsø7 (2015–2016). The present study included 20,438 participants, after having excluded respondents missing data on s-25(OH)D (n = 161) and/or subjective sleep measures (including sleep duration, insomnia, and daytime sleepiness)(n = 490). Based on s-25(OH)D (assessed using LC-MS/MS), participants were grouped as deficient (<30 nmol/L), insufficient (30–49.9 nmol/L), sufficient (50–75 nmol/L), or high (>75 nmol/L). Sleep duration was grouped as inadequate (ISD) if < 7 or ≥9 h. Linear and logistic regression were used to calculate unstandardized β-values and odds ratios [95% confidence intervals]. The analyses were adjusted for season, age, BMI, lifestyle factors and relevant comorbidities.

Results

In both men and women, s-25(OH)D was positively associated with sleep duration, and compared to the sufficient s-25(OH)D group, the insufficient s-25(OH)D group reported significantly shorter sleep duration in both sexes. There was an increased odds of ISD in both men and women but adjusted for confounding factors this was only significant in women (1.16 [1.03, 1.32], p = .017). In men, there were no significant associations between s-25(OH)D and the remaining sleep measures. Women in the high s-25(OH)D group had lower ESS-scores (−0.28 [-0.47, −0.08], p = .006), but higher odds of insomnia (1.16 [1.01, 1.33], p = .036) compared to women in the sufficient group.

Conclusions

In this Arctic population, a tenuous association was found between s-25(OH)D and subjective sleep measures, predominantly in women.

•

25(OH)D was associated with self-reported sleep measures in this Arctic population.

•

25(OH)D was positively associated with self-reported sleep duration in both sexes.

•

Women with sufficient 25(OH)D had lower odds of insomnia.

•

RCTs are needed to determine the role of vitamin D in sleep health.