Relationship between serum vitamin D level and sarcopenia in chronic liver disease

AIM

Although the association of vitamin D with primary sarcopenia has been extensively investigated, its relationship with secondary sarcopenia in patients with liver disease remains unclear. This study aimed to identify factors associated with sarcopenia in patients with chronic liver disease with a focus on serum vitamin D levels.

METHODS

The study included 204 patients with chronic liver disease. Independent factors significantly associated with sarcopenia were determined using multiple logistic regression analysis. The sarcopenia diagnosis was based on the sarcopenia criteria proposed by the Japan Society of Hepatology. Serum 25-hydroxyvitamin D₃ (25[OH]D₃ ) levels to represent serum vitamin D levels were measured using double-antibody radioimmunoassay, and vitamin D deficiency was defined as a serum 25(OH)D₃ level of ≤20 ng/mL.

RESULTS

The prevalence of sarcopenia in the cirrhotic patients (28/76, 36.8%) was significantly higher than that in the non-cirrhotic patients (18/128, 14.1%; P = 2.48 × 10^-4 ). Sarcopenia was diagnosed in 44 (27.5%) of the 160 patients with vitamin D deficiency, and two (4.5%) of the 44 patients without vitamin D deficiency (P = 4.90 × 10^-3 ). On multivariate analysis, advanced age (odds ratio 1.11; P = 2.10 × 10^-4 ), low body mass index (odds ratio 1.42; p = 2.08 × 10^-5 ), and low serum 25(OH)D₃ level (odds ratio 1.13; p = 1.20 × 10^-2 ) were significant, independent factors associated with sarcopenia. Serum 25(OH)D₃ was positively correlated with grip strength and skeletal muscle mass index.

CONCLUSION

Sarcopenia complicated by chronic liver disease was associated with advanced age, low body mass index, and low serum 25(OH)D₃ level.

Epigenetics Predicts Serum 25-Hydroxyvitamin D Response to Vitamin D3 Supplementation in African Americans

SCOPE

The effects of vitamin D₃ supplementations on circulating 25-hydroxyvitamin D [25(OH)D] are varied. The hypothesis that the baseline DNA methylation plays a role in the serum 25(OH)D response to vitamin D₃ supplementation is tested.

METHODS AND RESULTS

A randomized clinical trial is first conducted among 64 African Americans, who are randomly assigned to a placebo or a 16-week treatment of 600, 2000, and 4000 IU d^-1 of vitamin D₃ supplements. Expected serum 25(OH)D concentrations at posttest are estimated by intervention, age, gender, body mass index, baseline 25(OH)D concentrations, and seasonal variations. The 25(OH)D response is categorized into a high-response group when the actual 25(OH)D concentrations at posttest are higher than expected, and a low-response group otherwise. The 25(OH)D response is associated with baseline methylation levels of CYP family and VDR genes (raw p < 0.05). At a genome-wide level, the baseline methylation level of cg07873128 (OSBPL5) that regulates cholesterol balance and calcium homeostasis is higher in the low-response group (false discovery rate = 0.028).

CONCLUSIONS

The baseline methylation levels of CYP family and VDR modulate 25(OH)D response. In addition, the hypermethylation of cg07873128 at the baseline, which is located in the imprinted gene OSBPL5, may reduce the serum 25(OH)D response to vitamin D₃ supplementation.

In Pursuit of Vitamin D in Plants

Vitamin D deficiency is a global concern. Much research has concentrated on the endogenous synthesis of vitamin D in human skin following exposure to ultraviolet-B radiation (UV-B, 280–315 nm). In many regions of the world there is insufficient UV-B radiation during winter months for adequate vitamin D production, and even when there is sufficient UV-B radiation, lifestyles and concerns about the risks of sun exposure may lead to insufficient exposure and to vitamin D deficiency. In these situations, dietary intake of vitamin D from foods or supplements is important for maintaining optimal vitamin D status. Some foods, such as fatty fish and fish liver oils, certain meats, eggs, mushrooms, dairy, and fortified foods, can provide significant amounts of vitamin D when considered cumulatively across the diet. However, little research has focussed on assessing edible plant foods for potential vitamin D content. The biosynthesis of vitamin D in animals, fungi and yeasts is well established; it is less well known that vitamin D is also biosynthesised in plants. Research dates back to the early 1900s, beginning with in vivo experiments showing the anti-rachitic activity of plants consumed by animals with induced rickets, and in vitro experiments using analytical methods with limited sensitivity. The most sensitive, specific and reliable method for measuring vitamin D and its metabolites is by liquid chromatography tandem mass spectrometry (LC-MS/MS). These assays have only recently been customised to allow measurement in foods, including plant materials. This commentary focuses on the current knowledge and research gaps around vitamin D in plants, and the potential of edible plants as an additional source of vitamin D for humans.

Serum 25-hydroxyvitamin D and risk of venous thromboembolism: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Some evidence suggests that an inadequate vitamin D level may increase the risk for atherosclerotic cardiovascular disease. Whether a low vitamin D level plays a role in venous thromboembolism (VTE), that is, venous thrombosis and pulmonary embolism, is largely unexplored.

OBJECTIVES

We tested prospectively, in the Atherosclerosis Risk in Communities (ARIC) cohort, whether the serum level of 25-hydroxyvitamin D (25[OH]D) is inversely associated with VTE incidence, and whether it partly explains the African American excess of VTE in the ARIC Study.

PATIENTS AND METHODS

We measured 25(OH)D by using mass spectroscopy in stored samples of 12 752 ARIC Study participants, and followed them over a median of 19.7 years (1990-1992 to 2011) for the incidence of VTE (n = 537).

RESULTS

The seasonally adjusted 25(OH)D level was not associated with VTE incidence. In a model adjusted for age, race, sex, hormone replacement therapy, and body mass index, the hazard ratios of VTE across 25(OH)D quintiles 5 (high) to 1 (low) were: 1 (ref.), 0.84 (95% confidence interval [CI] 0.65-1.08), 0.88 (95% CI 0.68-1.13), 1.04 (95% CI 0.78-1.38), and 0.90 (95% CI 0.64-1.27). The lowest 25(OH)D quintile contained 59% African Americans, whereas the highest quintile contained 7% African Americans. However, lower 25(OH)D levels explained little of the 63% greater VTE risk of African Americans over whites in this cohort.

CONCLUSIONS

A low 25(OH)D level was not a risk factor for VTE in this prospective study. However, the totality of the literature (three studies) suggests that a low 25(OH)D level might modestly increase VTE risk in whites, but this needs further confirmation.

[Vitamin D and breast cancer: physiopathology, biological and clinical implications]

There is a recent increase in interest of vitamin D and breast cancer, facing the number of publications on the subject. This increase have several reasons, on the one hand, vitamin D deficiency is more and more prevalent and, on the other hand, there are new data that highlights the extra-bone effects of vitamin D, especially in breast cancer, the vitamin D is involved in the breast cancer risk factor, the prognosis, and the interaction with breast cancer treatments. This combination between vitamin D deficiency and breast cancer is extremely usual, and combined with all cancer clinical parameters: the incidence, the tumour biology, the clinical presentation, the prognosis, and the antineoplastic treatment tolerance. This vitamin D deficiency is increased after adjuvant cancer treatments. And yet, this problem increases bone metabolism disruptions in breast cancer patients, inducing osteoporotic risk at long time, even though this population is curable. This problem is therefore serious in the adjuvant breast cancer treatment. Unfortunately, in this population, the current recommendations are clearly insufficient, and the current randomized clinical trial results would contribute to define the best way to correct the vitamin D deficiency, quickly and secure.