Elderly disability associated with low Vitamin D – Jan 2024

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Serum 25-hydroxyvitamin D and risk of disability in activities of daily living among the oldest-old: an observational and Mendelian randomization study

Journal of Nutrition https://doi.org/10.1016/j.tjnut.2024.01.016
Xinwei Li PhD a b, Chen Chen PhD b, Yue Zhang PhD c, Jun Wang PhD b, Xingyao Cui MD a b, Lanjing Xu MD b d, Jinhui Zhou PhD b, Luojia Deng PhD c, Min Zhang MD a b, Yuebin Lv PhD b, Qiong Yu PhD a, Xiaoming Shi PhD b

Background
Vitamin D deficiency and disability are both prevalent among older adults. However, the association between them has rarely been investigated in oldest-old subjects (aged ≥ 80 years) and the causality remains unclear. This study aimed to elucidate the causal effect of vitamin D on the incident risk of disability in activities of daily living (ADL) among Chinese oldest-old based on the 2012-2018 Chinese Healthy Ageing and Biomarkers Cohort Study (HABCS).
Methods
Serum 25-hydroxyvitamin D (25(OH)D) concentrations and ADL status at baseline and follow-up interviews were documented. Cox regression models were applied among 1427 oldest-old (mean age, 91.2 years) with normal baseline ADL status. One-sample Mendelian randomization (MR) analyses were performed on a subset of 941 participants with qualified genetic data, using a 25(OH)D-associated genetic risk score as the genetic instrument.
Results
During a median follow-up of 3.4 years, 231 participants developed disability in ADL. Serum 25(OH)D concentration was inversely associated with risk of disability in ADL (per 10 nmol/L increase HR 0.85, 95%CI: 0.75, 0.96). Consistent results from MR analyses showed that a 10 nmol/L increment in genetically predicted 25(OH)D concentration corresponded to 20% reduced risk of ADL disability (HR 0.80, 95% CI: 0.68, 0.94). Non-linear MR demonstrated a monotonic declining curve with the hazard ratios exhibiting a more pronounced reduction among individuals with 25(OH)D concentrations below 50 nmol/L. Subgroups analyses showed the associations were more distinct among females and those with poorer health conditions.
Conclusion
Our study supports an inverse causal relationship between serum 25(OH)D concentration and risk of disability in ADL among Chinese oldest-old. This protective effect was more distinct especially for participants with vitamin D deficiency. Appropriate measures for improving vitamin D might help reduce the incidence of physical disability in this specific age group.
Introduction
The world is facing unprecedented challenges brought about by aging. The United Nations declared that the world’s population passed 8 billion people on the 15th of November 2022, representing a milestone in human development. As modern techniques and advancing medicine contribute to a notable increase in average life expectancy, the proportion of older people is predicted to reach 16% in 2050 according to the World Population Prospects 2022 (1). Thus, more importance should be attached to healthy aging and longevity for older adults, especially the oldest-old (adults aged ≥ 80 years), who suffer more from diseases and disabilities.
Vitamin D is a fat-soluble vitamin reported for its importance in maintaining and improving musculoskeletal health, which is vital for older adults (2). However, vitamin D deficiency is highly prevalent nowadays due to the current lifestyle and environmental factors that limit sunlight exposure (3). Data suggested that approximately 40% of Europeans are vitamin D deficient (4), and concentrations of 25-hydroxyvitamin D (25(OH)D) as low as 25 nmol/L are common in regions including South Asia and the Middle East (5). The situation worsens with aging due to alterations in both the production and metabolism of vitamin D, and the estimated age-related decline in vitamin D production was estimated as 13% per decade (6, 7). According to the 2010-2013 China National Nutrition and Health Survey, 34.1% of males and 44.0% of females over 60 had vitamin D deficiency (defined by a serum 25(OH)D concentration < 50 nmol/L) (8, 9). Vitamin D deficiency can be responsible for detrimental outcomes for older adults such as rickets, falls and sarcopenia (10), and further associated with various unfavorable conditions including cardiovascular diseases, metabolic syndrome, neurological diseases and cancer (11). These conditions collectively contribute to the development of disability in older adults.
Disability is a major public health concern particularly for older individuals, which impairs functional performance and restricts societal participation and activity levels. According to a World Health Organization report, the prevalence of disability among subjects aged 60 years and above was approximately 10.2% in 194 countries and territories (12). The pooled prevalence of disability reached 26.2% in China, and the rate was even higher for older individuals (13). There has been a consistent association of vitamin D with mortality(14) and physical function(15) among older adults. As vitamin D is essential in maintaining bone density and skeletal structure (16), the deficiency can result in conditions such as osteoporosis, fractures and reduced muscle mass, thereby affecting the physical function of the body. Adequate levels of vitamin D may also support normal immune function and alleviate chronic inflammation, which help hindering physiological aging process and decline in physical function (17). Lower vitamin D levels are reported to be associated with impaired physical function among older people in North American and European nations (18, 19, 20). Unfortunately, few large-scale, long-term intervention studies were able to show any benefit on improved physical performance from vitamin D supplementation (21, 22, 23).
Nevertheless, given the reluctance of oldest-old individuals aged over to participate in surveys, there is a lack of evidence on the epidemiological evidence of adverse effect of vitamin D deficiency for this specific group. Previous studies have shown that some physiological indices like BMI (24) and lipid indicators (25, 26) may have different impact on this age group compared to general population. Aside from the uncertainty of the relationship of vitamin D with physical disability, the causal direction also remains ambiguous. The rates of disability and vitamin D deficiency both worsen with increasing age, introducing the potential for reverse causality as lower levels of vitamin D might be due to insufficient sunlight exposure brought by limited physical mobility and less outdoor activities (3). Therefore, we attempted to explore the causal relationship among the oldest-old population using one-sample Mendelian randomization (MR) method. MR analysis combines the genetic instruments associated with the exposure of interest and the cohort data to assess the incidence of outcome, provide advantages in reducing susceptibility to confounding factors (27, 28) such as lifestyle and environmental exposures and mitigating the potential reverse causation. Furthermore, one-sample MR helps avoid sample heterogeneity as it requires obtaining exposure, outcome, and genetic data from the same population, allowing us to provide insights into the real causal relationship within this population subset under their unique health conditions and characteristics.
In this study, we used longitudinal data from Chinese oldest-old enrolled in the 2012-2018 Healthy Ageing and Biomarkers Cohort Study (HABCS). The cohort provides a large and representative sample of octogenarians, nonagenarians and centenarians and supports several novel findings regarding the oldest-old, which encouraged us to explore if the situation differs for this age group regarding vitamin D and physical disability. The study intended to: 1) explore the observational association of serum 25(OH)D concentration on incident risk of disability in activities of daily living (ADL) among the oldest-old population, and 2) validate the causal role of vitamin D on the risk of ADL disability through one-sample MR analyses by constructing a 25(OH)D-associated genetic risk score as the genetic instrument.
Section snippets
Study Population
Participants were collected from the HABCS, which was initiated in 2008 in eight longevity areas across China and featured by the largest community-based multi-wave study of Chinese older adults and especially with regard to the oldest old (29). The cohort continued with follow-ups and the recruitment of new participants in 2012, 2014, and 2018. General personal information was collected using standardized questionnaires through face-to-face interviews, and anthropometric measurements were.. . .
Results
The baseline characteristics of the participants are presented in Table 1. Among the 1427 oldest-old, 550 (38.5%) were male, and the average measured concentration of 25(OH)D was 40.9 ± 18.6 nmol/L. During a mean (SD) follow-up of 3.4 (1.6) years, there were 231 participants who were documented to develop ADL disability. The ages of the participants ranged from 80 to 112 years, with a mean (SD) age of 91.2 ± 7.5 years. Among the 941 participants selected for MR analyses, the mean age (91.3±7.9)  . . .
Discussion
In this study based on a community-based cohort of the Chinese oldest-old, we first observed inverse associations between serum 25(OH)D concentrations and incident risk of disability in ADL. Linear and non-linear MR analyses further offered consistent results which validated the existence of causal protective role of vitamin D on risk of disability in ADL. Additionally, non-linear results suggested that the beneficial effects brought by an increase in 25(OH)D concentrations seemed more evident….
Conclusion
Based on a cohort of the Chinese oldest-old, we reported an inverse causal association between serum 25(OH)D concentration and disability in ADL using one-sample MR methods. Non-linear fitting results call for more attention on improving vitamin D levels among older people with 25(OH)D concentration below 50 nmol/L. These findings emphasize that approaches to improve vitamin D among the oldest-old may help reduce the occurrence of physical disability, especially for those who already have a….

References online

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17+ VitaminDWiki pages have FRAILTY in the title

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VitaminDWiki – Seniors contains:

431 items in Seniors

see also
Overview Seniors and Vitamin D
Muscles and Vitamin D - many studies 125+ items
Overview Fractures and Falls and Vitamin D

Falls and Fractures category listing has 258 items along with related searches

Overview Alzheimer's-Cognition and Vitamin D
Overview Cancer and vitamin D
Overview Influenza and vitamin D

Cancer - Prostate category listing has 103 items along with related searches

Overview Diabetes and vitamin D
Hearing Loss appears to be prevented and treated with vitamin D

Mortality category listing has 321 items along with related searches

Overview Osteoporosis and vitamin D
Restless Legs Syndrome dramatically reduced by vitamin D, etc
Overview Rheumatoid Arthritis and vitamin D
Frailty and Vitamin D - many studies many studies
Nursing homes and Vitamin D - many studies
13 reasons why many seniors need more vitamin D (both dose and level) - July 2023 has:

1. Senior skin produces 4X less Vitamin D for the same sun intensity
2. Seniors have fewer vitamin D receptor genes as they age
   Receptors are needed to get Vitamin D in blood actually into the cells
3. Many other Vitamin D genes decrease with age
4. Since many gene activations are not detected by a blood test,
   more Vitamin D is often needed, especially by seniors
5. Seniors are indoors more than when they were younger
   not as agile, weaker muscles; frail, no longer enjoy hot temperatures
6. Seniors wear more clothing outdoors than when younger
   Seniors also are told to fear skin cancer & wrinkles
7. Seniors often take various drugs which end up reducing vitamin D
   Some reductions are not detected by a vitamin D test of the blood
   statins, chemotherapy, anti-depressants, blood pressure, beta-blockers, etc
8. Seniors often have one or more diseases that consume vitamin D
   osteoporosis, diabetes, Multiple Sclerosis, Cancer, ...
9. Seniors generally put on weight as they age - and a heavier body requires more vitamin D
10. Seniors often (40%) have fatty livers – which do not process vitamin D as well
11. Reduced stomach acid means less Magnesium is available to get vitamin D into the cells
12. Vitamin D is not as bioavailable in senior intestines
13. Seniors with poorly functioning kidneys do not process vitamin D as well
14. Glutathione (which increases Vitamin D getting to cells) decreases with age
       Seniors category has 431 items

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VitaminDwiki Seniors category is associated with 37 categories – examples

Sports (Muscle) 37+, Virus 17+, Breathing 14+, Falls & Fractures 13+, Mortality 13+, Cardiovascular 10+, Depression 10+, Cognitive 7+, Omega-3 9+, Magnesium 8+