Plasma n-3 Polyunsaturated Fatty Acids and Bone Mineral Density in Renal Transplant Recipients

The Prevalence and Risk Factors of Low Bone Mineral Density in the Population of the Abay Region of Kazakhstan

Osteoporosis is considered a serious public health problem that particularly affects the postmenopausal period. In 2018, in the Republic of Kazakhstan, the prevalence of osteoporosis was 10.0, and the incidence was 3.7 new cases, per 100,000 adults, respectively. The objective of this study was to assess the prevalence of osteoporosis and indicate the main factors affecting low bone mineral density by screening the adult population of the Abay region, Kazakhstan. The target group comprised 641 respondents aged between 18 and 65 years old, from a Kazakh population, who had been living in the Abay region since birth. All participants filled out a questionnaire and were subjected to a bone mineral density measurement by means of dual-energy X-ray absorptiometry (DXA) between 15 July 2023 and 29 February 2024. Logistic regression analysis was conducted to assess the association between low bone mineral density and key demographic characteristics, such as lifestyle factors and nutritional habits. We identified the prevalence of low bone mass (osteopenia) and osteoporosis to be 34.1%, with the highest prevalence of 48.3% being found in the older population group (50+ years). The regression analysis revealed a number of indicators associated with the likelihood of bone sparing. However, only four of these showed significance in the final multivariate model (R2 = 22.4%). These were age (adjusted odds ratio (AOR) 1.05) and fracture history (AOR 1.64) directly associated with the likelihood of low bone density. Meanwhile, the body mass index (AOR 0.92) and the consumption of nuts and dried fruits (AOR 0.48) reduced the chance of bone tissue demineralization. Additional studies examining the prevalence and any emerging risk factors for osteoporosis are needed to advance clinical epidemiological knowledge and implement public health programs.

Prevalence of Musculoskeletal and Metabolic Disorders in Kidney Transplant Recipients: A Systematic Review and Meta-Analysis

Introduction

Musculoskeletal disorders could be associated with metabolic disorders that are common after kidney transplantation, which could reduce the quality of life of patients. The aim of this study was to assess the prevalence of both musculoskeletal and metabolic disorders in kidney transplant patients.

Methods

MEDLINE, CINAHL, Cochrane Library, EMBASE and Web of Science were searched from their inception up to June 2023. DerSimonian and Laird random-effects method was used to calculate pooled prevalence estimates and their 95% confidence intervals (CIs).

Results

21,879 kidney transplant recipients from 38 studies were analysed. The overall proportion of kidney transplant patients with musculoskeletal disorders was 27.2% (95% CI: 18.4-36.0), with low muscle strength (64.5%; 95% CI: 43.1-81.3) being the most common disorder. Otherwise, the overall proportion of kidney transplant patients with metabolic disorders was 37.6% (95% CI: 21.9-53.2), with hypovitaminosis D (81.8%; 95% CI: 67.2-90.8) being the most prevalent disorder.

Conclusion

The most common musculoskeletal disorders were low muscle strength, femoral osteopenia, and low muscle mass. Hypovitaminosis D, hyperparathyroidism, and hyperuricemia were also the most common metabolic disorders. These disorders could be associated with poorer quality of life in kidney transplant recipients.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier [CRD42023449171].

Associations of Changes in Bone Turnover Markers with Change in Bone Mineral Density in Kidney Transplant Patients

BACKGROUND

Bone loss after kidney transplantation is highly variable. We investigated whether changes in bone turnover markers associate with bone loss during the first post-transplant year.

METHODS

Bone mineral density (BMD) was measured at 0 and 12 months, with biointact parathyroid hormone, bone-specific alkaline phosphatase (BALP), intact procollagen type I N -terminal propeptide (PINP), and tartrate-resistant acid phosphatase isoform 5b (TRAP5b) measured at 0, 3, and 12 months post-transplant ( N =209). Paired transiliac bone biopsies were available in a subset ( n =49). Between-group differences were evaluated by Student's t test, Wilcoxon signed-rank test, or Pearson's chi-squared test.

RESULTS

Changes in BMD varied from -22% to +17%/yr. Compared with patients with no change (±2.5%/yr), patients who gained BMD had higher levels of parathyroid hormone (236 versus 136 pg/ml), BALP (31.7 versus 18.8 μ g/L), and Intact PINP (121.9 versus 70.4 μ g/L) at time of transplantation; a greater decrease in BALP (-40% versus -21%) and Intact PINP (-43% versus -13%) by 3 months; and lower levels of Intact PINP (36.3 versus 60.0 μ g/L) at 12 months post-transplant. Patients who lost BMD had a less marked decrease, or even increase, in Intact PINP (+22% versus -13%) and TRAP5b (-27% versus -43%) at 3 months and higher Intact PINP (83.7 versus 60.0 μ g/L) and TRAP5b (3.89 versus 3.16 U/L) at 12 months compared with patients with no change. If none of the biomarkers decreased by the least significant change at 3 months, an almost two-fold (69% versus 36%) higher occurrence of bone loss was seen at 12 months post-transplant.

CONCLUSIONS

Bone loss after kidney transplantation was highly variable. Resolution of high bone turnover, as reflected by decreasing bone turnover markers, associated with BMD gain, while increasing bone turnover markers associated with bone loss.

Effects and Reversibility of Pre- and Post-natal Iron and Omega-3 Fatty Acid Deficiency, Alone and in Combination, on Bone Development in Rats

Both iron and omega-3 (n-3) polyunsaturated fatty acids may play an important role in bone development. The aim of this study was to investigate the effects of pre- and post-natal iron and n-3 fatty acid deficiency (FAD), alone and in combination, on bone development in rats, and to determine whether effects are reversible when a sufficient diet is provided post-weaning. Using a 2×2-factorial design, 56 female Wistar rats were allocated to one of four diets: (1) control, (2) iron deficient (ID), (3) n-3 FAD or (4) ID and n-3 FAD, and were maintained on the respective diets throughout gestation and lactation. At weaning (post-natal day [PND] 21), offspring (n = 24/group; male:female=1:1) were randomly allocated to either continue with their respective diets or to switch to the control diet until PND 42-45. Bone mineral density (BMD) and bone strength were determined using dual X-ray absorptiometry and three-point bending tests, respectively. Pre- and post-natal ID resulted in significantly lower BMD in the spine and bone strength in the left femur. Both ID and n-3 FAD resulted in lower BMD in the right femur, with an additive reduction in the combined ID and n-3 FAD group vs. controls. While negative effects of pre- and post-natal ID alone were reversed in offspring switched to a control diet post-weaning, lower BMD and bone strength persisted in offspring with combined ID and n-3 FAD during the prenatal and early post-natal period. Effects were not sex-specific. These results indicate that ID during early life may negatively influence bone development, with potential additive effects of n-3 FAD. While the effects of ID alone seem reversible, a combined ID and n-3 FAD may result in irreversible deficits in bone development.

Marine n-3 Polyunsaturated Fatty Acids and Bone Mineral Density in Kidney Transplant Recipients: A Randomized, Placebo-Controlled Trial

Kidney transplant recipients are at high risk of progressive bone loss and low-energy fractures in the years following transplantation. Marine n-3 polyunsaturated fatty acids (n-3 PUFA) supplementation may have beneficial effects on bone strength. The Omega-3 fatty acids in Renal Transplantation (ORENTRA) trial was an investigator initiated, randomized, placebo-controlled trial investigating the effects of marine n-3 PUFA supplementation after kidney transplantation. Effects of supplementation on bone mineral density (BMD) and calcium metabolism were pre-defined secondary endpoints. Adult kidney transplant recipients (n = 132) were randomized to 2.6 g marine n-3 PUFA supplement or olive oil (control) from 8 to 52 weeks post-transplant. Dual energy X-ray absorptiometry was performed to assess changes in bone mineral density of hip, spine, and forearm, as well as trabecular bone score (TBS) of the lumbar spine. Student's t test was used to assess between-group differences. There were no differences in ΔBMD between the two groups (intervention vs. control) at lumbar spine (-0.020 ± 0.08 vs. -0.007 ± 0.07 g/cm², p = 0.34), total hip (0.001 ± 0.03 vs. -0.005 ± 0.04, p = 0.38), or other skeletal sites in the intention-to-treat analyses. There was no difference in the change in TBS score (0.001 ± 0.096 vs. 0.009 ± 0.102, p = 0.62). Finally, no effect on biochemical parameters of mineral metabolism was seen. Results were similar when analyzed per protocol. In conclusion, we found no significant effect of 44 weeks of supplementation with 2.6 g of marine n-3 PUFA on BMD in kidney transplant recipients.

Effects of a plant-based fatty acid supplement and a powdered fruit, vegetable and berry juice concentrate on omega-3-indices and serum micronutrient concentrations in healthy subjects

The major aim of this controlled, randomised, open-labelled, parallel-grouped, clinical trial was to investigate whether supplementation with different dosages of omega-3 fatty acids (0.5 g/d and 1 g/d) from a plant-based fatty acid supplement affected omega-3-indices (O3I) in well-nourished, healthy people. In addition, the combined ingestion of the plant-based fatty acid supplement, together with an encapsulated fruit, vegetable and berry (FVB) juice powder concentrate, was applied in order to observe the absorption of certain micronutrients and to examine some aspects related to the safe consumption of the products. The data demonstrate that the intake of only 0.5 g/day of omega-3 fatty acids from of a vegan supplement was able to increase the O3I significantly after 8 and 16 weeks. The combined ingestion with the FVB supplement concurrently increased serum concentrations of specific vitamins and carotenoids without effects on hepatic, kidney and thyroid function or changes in blood lipids.