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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.
Li, X, Chen, C, Zhang, Y, Wang, J, Cui, X, Xu, L, Zhou, J, Deng, L, Zhang, M, Lv, Y, et al
The Journal of nutrition. 2024;(3):1004-1013
Abstract
BACKGROUND Vitamin D deficiency and disability are both prevalent among older adults. However, the association between them has rarely been investigated in the oldest-old subjects (aged ≥80 y), and the causality remains unclear. OBJECTIVE 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. 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 y) 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 y, 231 participants developed disability in ADL. Serum 25(OH)D concentration was inversely associated with the risk of disability in ADL [per 10 nmol/L increase hazard ratio (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 a 20% reduced risk of ADL disability (HR 0.80; 95% CI: 0.68, 0.94). Nonlinear MR demonstrated a monotonic declining curve, with the HRs exhibiting a more pronounced reduction among individuals with 25(OH)D concentrations below 50 nmol/L. Subgroup analyses showed that the associations were more distinct among females and those with poorer health conditions. CONCLUSIONS Our study supports an inverse causal relationship between serum 25(OH)D concentration and the 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.
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Vitamin D status in women with dichorionic twin pregnancies and their neonates: a pilot study in China.
Li, X, Yu, J, Wen, L, Li, Q, Yan, J, Tian, J, Tong, C, Tong, Q, Qi, H, Saffery, R, et al
BMC pregnancy and childbirth. 2021;(1):279
Abstract
BACKGROUND Vitamin D deficiency is a global public health issue in women and children and is associated with adverse impacts on child growth, such as rickets. However, prior studies have mainly focused on measuring vitamin D levels in singleton pregnant women and their offspring, and very limited studies have revealed the prevalence of vitamin D deficiency in twin pregnant women and their offspring. The aim of this study was to investigate vitamin D levels in twin-pregnant women and their neonates. We also explored the correlation of maternal vitamin D levels with neonatal outcomes and infant growth. METHODS A prospective subcohort investigation was carried out among 72 dichorionic, diamniotic twin-pregnant mothers and their twin offspring from the Longitudinal Twin Study. Peripheral blood was collected from the mothers in the third trimester, and cord blood was collected from neonates at birth to identify 25[OH]D levels. Data on the characteristics of the mothers and neonates were collected. Infant growth data and food sensitivities were also collected. RESULTS The average maternal 25[OH]D level was 31.78 ng/mL, with 19.4% being deficient and 20.8% insufficient, while the average neonatal 25[OH]D level was 15.37 ng/mL, with 99.3% being deficiency or insufficient. A positive correlation was found between maternal and neonatal 25[OH]D levels (beta-value: 0.43, 95% CI: 0.37, 0.49). Interestingly, the higher the maternal 25[OH]D level was, the smaller the cotwin birthweight discordance (beta-value: -2.67, 95% CI: - 5.11, - 0.23). In addition, the infants of mothers with vitamin D deficiency were more likely to be allergic to foods at 6 months than those of mothers with vitamin D sufficiency. CONCLUSIONS Twin neonates were at high risk of vitamin D deficiency, although their mothers' vitamin D deficiency partially improved. Higher maternal vitamin D levels were associated with smaller discordance of cotwin birthweight. TRIAL REGISTRATION Chinese Clinical Trial Registry ChiCTR-OOC-16008203 , 1st April 2016.
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The efficacy of vitamin D therapy for patients with COPD: a meta-analysis of randomized controlled trials.
Li, X, He, J, Yu, M, Sun, J
Annals of palliative medicine. 2020;(2):286-297
Abstract
BACKGROUND Many studies have demonstrated that vitamin D has clinical benefits when used to treat patients with chronic obstructive pulmonary disease (COPD). However, most of these studies have insufficient samples or inconsistent results. The aim of this meta-analysis was to evaluate the effects of vitamin D therapy in patients with COPD. METHODS We performed an electronic literature search of the databases PubMed, China National Knowledge Internet (CNKI), Embase, Web of Science and Wanfang Data. Meta-analysis was carried out by Review Manager Version 5.3 (Revman 5.3), and standardized mean difference (SMD) and mean difference (MD) were used to assess the efficacy of vitamin D therapy in patients with COPD. RESULTS A total of 25 articles involving 2,670 participants were included in this study. The overall results showed a statistical significance of vitamin D therapy in patients with COPD on forced expiratory volume in 1 second (FEV1) (SMD: 1.21, 95% CI: 0.76-1.66, P<0.01), FEV1/FVC (SMD: 1.07, 95% CI: 0.56-1.58, P<0.01), Exacerbations (SMD: 0.39, 95% CI: 0.23-0.64, P<0.01), Sputum volume (SMD: -6.02, 95% CI: -8.25 to 3.79, P<0.01), 6-minute walk distance (6MWD) (MD: 8.82, 95% CI: 1.67-15.98, P=0.02) and COPD assessment test (CAT) score (SMD: -1.19, 95% CI: -1.74 to 0.63, P<0.01). CONCLUSIONS Our analysis indicated that vitamin D used in patients with COPD could improve the lung function (FEV1, FEV1/FVC), 6MWD and reduce acute exacerbation, sputum volume and CAT score.
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Association between serum vitamin D levels and venous thromboembolism (VTE): A systematic review and meta-analysis of observational studies.
Wan, J, Yuan, J, Li, X, Bao, Y, Hou, Y, Li, Z, Tan, SC, Low, TY, Chu, Y
Complementary therapies in medicine. 2020;:102579
Abstract
OBJECTIVE Although many studies have attempted to unravel the relationship between vitamin D deficiency and the incidence of VTE, the results remained inconsistent. To address this discrepancy, we performed a systematic review and meta-analysis to precisely disentangle the relationship between serum vitamin D levels and VTE risk. METHODS The Web of Science, Scopus, PubMed/Medline, Embase, and Google Scholar databases were searched for all available observational studies that reported the risk of venous thromboembolism (VTE) based on serum vitamin D levels categories. The search was performed up to March 2020. RESULTS Seven studies were included. The overall analysis showed a significantly increased risk of VTE in subjects with low levels of serum vitamin D compared with those with normal vitamin D levels (RR = 1.34; 95% CI: 1.07-1.69; P = 0.011). In a sensitivity analysis, we did not observe a significant effect of any individual study on the combined effect sizes. Nevertheless, significant heterogeneity was present among the studies (Cochrane Q test, p = 0.018, I2 = 61%). In the stratified analysis, low vitamin D levels were positively associated with an increased risk of VTE in prospective population-based studies (RR = 1.31; 95% CI: 1.06-1.61; P = 0.010) and in subjects below 60 years old (RR = 1.28; 95% CI: 1.07-1.54; P = 0.060). CONCLUSION our systematic review and meta-analysis showed that a low serum vitamin D level was indeed associated with an increased risk of VTE.
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Serum Vitamin D Affected Type 2 Diabetes though Altering Lipid Profile and Modified the Effects of Testosterone on Diabetes Status.
Wang, L, Liu, X, Hou, J, Wei, D, Liu, P, Fan, K, Zhang, L, Nie, L, Li, X, Huo, W, et al
Nutrients. 2020;(1)
Abstract
Numerous studies have investigated the associations between serum vitamin D or testosterone and diabetes; however, inconsistencies are observed. Whether there is an interaction between vitamin D and testosterone and whether the lipid profile (total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)) mediates the association between vitamin D and diabetes is unclear. To investigate the effect of vitamin D and testosterone on impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2DM), 2659 participants from the Henan Rural Cohort were included in the case-control study. Generalized linear models were utilized to estimate associations of vitamin D with IFG or T2DM and interactive effects of vitamin D and testosterone on IFG or T2DM. Principal component analysis (PCA) and mediation analysis were used to estimate whether the lipid profile mediated the association of vitamin D with IFG or T2DM. Serum 25(OH)D3, 25(OH)D2, and total 25(OH)D levels were negatively correlated with IFG (odds ratios (ORs) (95% confidence intervals (CIs)): 0.99 (0.97, 1.00), 0.85 (0.82, 0.88), and 0.97 (0.96, 0.98), respectively). Similarity results for associations between serum 25(OH)D2 and total 25(OH)D with T2DM (ORs (95%CIs): 0.84 (0.81, 0.88) and 0.97 (0.96, 0.99)) were observed, whereas serum 25(OH)D3 was negatively correlated to T2DM only in the quartile 2 (Q2) and Q3 groups (both p < 0.05). The lipid profile, mainly TC and TG, partly mediated the relationship between 25(OH)D2 or total 25(OH)D and IFG or T2DM and the proportion explained was from 2.74 to 17.46%. Furthermore, interactive effects of serum 25(OH)D2, total 25(OH)D, and testosterone on T2DM were observed in females (both p for interactive <0.05), implying that the positive association between serum testosterone and T2DM was vanished when 25(OH)D2 was higher than 10.04 ng/mL or total 25(OH)D was higher than 40.04 ng/mL. Therefore, ensuring adequate vitamin D levels could reduce the prevalence of IFG and T2DM, especially in females with high levels of testosterone.
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Comparison of fracture risk using different supplemental doses of vitamin D, calcium or their combination: a network meta-analysis of randomised controlled trials.
Hu, ZC, Tang, Q, Sang, CM, Tang, L, Li, X, Zheng, G, Feng, ZH, Xuan, JW, Shen, ZH, Shen, LY, et al
BMJ open. 2019;(10):e024595
Abstract
OBJECTIVE Inconsistent findings in regard to association between different concentrations of vitamin D, calcium or their combination and the risk of fracture have been reported during the past decade in community-dwelling older people. This study was designed to compare the fracture risk using different concentrations of vitamin D, calcium or their combination. DESIGN A systematic review and network meta-analysis. DATA SOURCES Randomised controlled trials in PubMed, Cochrane library and Embase databases were systematically searched from the inception dates to 31 December 2017. OUTCOMES Total fracture was defined as the primary outcome. Secondary outcomes were hip fracture and vertebral fracture. Due to the consistency of the original studies, a consistency model was adopted. RESULTS A total of 25 randomised controlled trials involving 43 510 participants fulfilled the inclusion criteria. There was no evidence that the risk of total fracture was reduced using different concentrations of vitamin D, calcium or their combination compared with placebo or no treatment. No significant associations were found between calcium, vitamin D, or combined calcium and vitamin D supplements and the incidence of hip or vertebral fractures. CONCLUSIONS The use of supplements that included calcium, vitamin D or both was not found to be better than placebo or no treatment in terms of risk of fractures among community-dwelling older adults. It means the routine use of these supplements in community-dwelling older people should be treated more carefully. PROSPERO REGISTRATION NUMBER CRD42017079624.
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Vitamin D concentration and risk of Alzheimer disease: A meta-analysis of prospective cohort studies.
Yang, K, Chen, J, Li, X, Zhou, Y
Medicine. 2019;(35):e16804
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Abstract
BACKGROUND Considerable controversy exists on the association between serum vitamin D concentrations and Alzheimer disease (AD) risk. This study aimed to synthesize the association of serum vitamin D concentrations with AD in adults. METHODS PubMed, Embase, and Cochrane library databases were searched for prospective cohort studies with data on serum vitamin D concentrations and AD risk. RESULT The studies that reported the adjusted relative risks (RRs) with 95% confidence intervals (CIs) of AD associated with serum vitamin D concentrations were included and subjected to subgroup analyses. Six prospective cohort studies with 1607 AD cases and 21,692 individuals were included in the meta-analysis. In 4 cohort studies with information about serum vitamin D concentrations <25 and 25 to 50 nmol/L, the random effects summary estimate did not show an increased risk of AD after adjustment for the established risk factors, while 3 cohort studies reported the RRs for incident AD per standard deviation (SD) decrease in serum vitamin D concentration and the random effects summary estimate did not show an increased risk of AD after adjustment for the established risk factors. CONCLUSIONS The current meta-analysis indicated that serum vitamin D deficiency (<25 nmol/L) or insufficiency (25-50 nmol/L) was not statistically significant and associated with the risk of AD.
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Lipoprotein lipase links vitamin D, insulin resistance, and type 2 diabetes: a cross-sectional epidemiological study.
Huang, Y, Li, X, Wang, M, Ning, H, A, L, Li, Y, Sun, C
Cardiovascular diabetology. 2013;:17
Abstract
BACKGROUND Lipoprotein lipase (LPL) and serum 25-hydroxyvitamin D [25(OH)D] play important roles in the regulation of lipid metabolism. Although dyslipidemia is associated with insulin resistance (IR) and type 2 diabetes (T2D), there are limited data available regarding the relationship of LPL and 25(OH)D to IR and T2D at a population level. The objective of the present study is to investigate the associations of LPL and 25(OH)D with IR and T2D in a Chinese population. METHODS The study cohort consisted of 2708 subjects (1326 males, 1382 females; mean age 48.5 ± 12.6 years) in main communities of Harbin, China. Serum 25(OH)D, LPL, free fatty acids (FFAs), fasting glucose (FG), fasting insulin, lipid profile, apoA and apoB concentrations were measured. RESULTS Serum 25(OH)D concentration was positively associated with LPL (β = 0.168, P < 0.001). LPL was inversely associated with IR and T2D. Subjects in the lowest quartile of LPL had the highest risk of IR [odds ratio (OR) = 1.85, 95% CI = 1.22-2.68] and T2D (OR = 1.65, 95% CI = 1.14-2.38). Serum 25(OH)D was also inversely associated with IR and T2D. Vitamin D deficiency [25(OH)D < 20 ng/ml] was associated with an increasing risk of IR (OR = 1.91, 95% CI = 1.23-2.76) and T2D (OR = 2.06, 95% CI = 1.37-3.24). The associations of 25(OH)D with IR and T2D were attenuated by further adjustment for LPL. CONCLUSIONS LPL is associated with serum 25(OH)D, IR and T2D in the Chinese population. These results suggest a potential mediating role of LPL in the associations of 25(OH)D with IR and T2D.