Factors Associated with Inadequate Vitamin D Levels in Older Chinese Adults

by | Nov 14, 2023 | 2023, Aging, Vitamin D - Recommended Levels

Written by Harold Oster, MD. Results suggest that vitamin D insufficiency is more likely in women, ethnic minorities, residents of temperate latitudes and urban areas, and those with obesity or anemia. 

vitamin DThe prevalence of vitamin D insufficiency is increasing worldwide. Inadequate vitamin D levels can lead to osteoporosis and other bone disorders and has been linked in some studies to an increased risk of infections, diabetes, and overall mortality1.

Yichun Hu et al. studied the factors associated with vitamin D insufficiency in participants sixty years of age and older in the China Adult Chronic Disease and Nutrition Survey, a large cross-sectional study examining nutrition and associated health conditions in Chinese adults2. Questionnaires were used to obtain data on age, sex, location, ethnicity, marital status, and level of education. Height, weight, and waist circumference were measured, and blood was tested for hemoglobin and vitamin D levels. A 25(OH)D level of 20 ng/ml or higher was defined as adequate, between 12 ng/ml and 20 ng/ml as insufficient, and less than 12 ng/ml as deficient. Odds and prevalence ratios, statistical techniques to assess the association of a factor with a condition3,4, were performed.

The authors noted the following:

  • There were 6,273 participants included in the study.
  • The median 25(OH)D level was 18.48 ng/ml.
  • The prevalence of vitamin D deficiency, insufficiency, and sufficiency was 22.17%, 36.41%, and 41.73%, respectively.
  • Males had a higher prevalence of vitamin D sufficiency than females. (50.65% vs. 33.5%)
  • Participants younger than 70 were more likely to have sufficient vitamin D levels than those over 70. (44% vs. 39%)
  • Participants of the Han ethnic majority were less likely to be vitamin D deficient than the other ethnicities.
  • Married participants had higher vitamin D levels than unmarried participants and those living alone. (18.78 ng/ml vs. 17.01 ng/ml.
  • Participants who had a middle or college education were more likely to have inadequate vitamin D levels than those with only a primary education.
  • As body mass index increased, the rate of vitamin D sufficiency decreased. As abdominal obesity increased, the rate of vitamin D sufficiency decreased.
  • Participants living in the warm and medium temperature zones had higher rates of vitamin D inadequacy than those living in the tropical zone.
  • Participants living in urban areas were less likely than those living in rural areas to have sufficient vitamin D levels.
  • Anemic patients were more likely to have inadequate vitamin D levels than those without anemia.

Results suggest that the likelihood of vitamin D insufficiency is increased in women, older individuals, ethnic minorities, residents of temperate climates and urban areas, people living alone, and those with abdominal obesity or anemia. A limitation of the study was the lack of assessment of the causes of inadequate vitamin D levels in the various groups.

Source: Hu, Yichun, Rui Wang, Deqian Mao, Jing Chen, Min Li, Weidong Li, Xiaoguang Yang, and Lichen Yang. “Vitamin D Status and Associated Factors of Older Adults in the Cross-Sectional 2015–2017 Survey.” Nutrients 15, no. 20 (2023): 4476.

© 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 November 14, 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:

  1. Amrein K, Scherkl M, Hoffmann M, et al. Vitamin D deficiency 2.0: an update on the current status worldwide. Eur J Clin Nutr. Nov 2020;74(11):1498-1513. doi:10.1038/s41430-020-0558-y
  2. Yu D, Zhao L, Zhang J, et al. China Nutrition and Health Surveys (1982-2017). China CDC Wkly. Feb 26 2021;3(9):193-195. doi:10.46234/ccdcw2021.058
  3. Szumilas M. Explaining odds ratios. J Can Acad Child Adolesc Psychiatry. Aug 2010;19(3):227-9.
  4. Petersen MR, Deddens JA. A comparison of two methods for estimating prevalence ratios. BMC Med Res Methodol. Feb 28 2008;8:9. doi:10.1186/1471-2288-8-9