Association of Vitamin D3 Levels with Cognitive Impairment and Sleep Quality in Older Adults

by | Oct 19, 2023 | 2023, Aging, Brain Health, Cognitive Health, Sleep, Vitamin D - General

Written By Harold Oster, MD. Results suggest that normal cognitive function is positively associated with sufficient vitamin D3 levels and good sleep quality.

man sleepingThe prevalence of cognitive impairment has increased with the rising life expectancy of the population. More than fifteen percent of people over 75 years old are affected by dementia1, and an additional ten to twenty percent have mild cognitive impairment2. Short sleep duration and poor quality of sleep have been linked to cognitive decline in older adults3. Vitamin D3 deficiency is associated with poor sleep quality and short sleep duration4.

Yuning Xie et al. studied the associations between vitamin D3 levels, cognitive impairment, sleep duration, and sleep quality in older adults. Data was obtained from 3412 individuals evaluated in 2011 and 2014 as part of a large, longitudinal study in China. About 40% of the participants were evaluated both in 2011 and 2014. The level of cognitive impairment was assessed by the Chinese version of the Mini-Mental Status Exam (MMSE), a validated 23-question test with a range of 0-30, with participants scoring 24 and above considered unimpaired5. Vitamin D3 levels were drawn: less than 25 nmol/L was classified as deficient, 25 to less than 50 nmol/L as insufficient, and 50 nmol/l or greater as sufficient. The participants were questioned about sleep duration, which was categorized as short (less than six hours), normal (seven to eight hours), and long (greater than nine hours). Overall sleep quality was evaluated with a question from the validated Pittsburgh Sleep Quality Index (PSQI)6, and participants were grouped into two categories: very good/good and fair/bad/very bad. Participants were evaluated for demographic, socio-economic, and health-related potential covariables.

The authors noted the following:

  • The mean vitamin D3 level was 6 nmol/L, with about 20% being deficient, 50% insufficient, and 30% sufficient.
  • After controlling for demographic factors and education, compared to participants deficient in vitamin D3, those in the insufficient category had a 43% lower odds of being cognitively impaired. Those with sufficient levels of vitamin D3 had 63% lower odds of being cognitively impaired. Adjusting for potential confounding variables affected the odds slightly, but they remained statistically significant.
  • Good sleep quality was associated with 51% lower odds of being cognitively impaired.
  • After controlling for all potential covariates, sleep duration was not significantly associated with vitamin D3
  • Participants with good sleep quality and sufficient vitamin D3 levels had 47% lower odds of cognitive impairment compared to those who had deficient levels of vitamin D3 and fair/bad sleep quality.

Results of the study suggest that poor sleep quality and inadequate levels of vitamin D3 are associated with cognitive impairment in older adults. Limitations include the self-reporting of sleep quality and duration and potential residual confounding variables.

Source: Xie, Yuning, Chen Bai, Qiushi Feng, and Danan Gu. “Serum Vitamin D3 Concentration, Sleep, and Cognitive Impairment among Older Adults in China.” Nutrients 15, no. 19 (2023): 4192.

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). 

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Posted October 19, 2023.

Harold Oster, MD graduated from medical school in Miami, Florida in 1992 and moved to Minnesota in 2004. After more than 25 years of practicing Internal Medicine, he recently retired. Dr. Oster is especially interested in nutrition, weight management, and disease prevention. Visit his website at haroldoster.com.

References:

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