Vitamin D deficiency, functional status, and balance in older adults with osteoarthritis.

BACKGROUND: Low vitamin D levels are associated with a more severe case of knee osteoarthritis (OA). However, there are few published reports concerning an association between vitamin D deficiency and functional status of individuals with OA and no reports about postural balance in this population. AIM: To analyze the relationship between vitamin D deficiency and severity, functional status, and balance in elderly patients with OA. METHODS: In this cross-sectional study, 105 elderly patients with hip and knee OA were included. The severity was assessed by the Kellgren-Lawrence criteria. The functional status was assessed with the Lequesne index. Postural balance was assessed using a force platform, and center-of-pressure parameters (velocity at anteroposterior and mediolateral axis) were used as the balance outcomes. Serum 25(OH) vitamin D levels were measured using a chemiluminescence method. RESULTS: Most of the patients (mean age: 70.6 ± 6.5 years) were female (n = 78, 74.3%). In the group with vitamin D deficiency, 43 patients (56.6%) had severe OA, while 33 patients (43.4%) had mild or moderate OA (χ 2 test, P = 0.04). Patients with vitamin D deficiency showed a higher Lequesne index score (Mann-Whitney test, P = 0.04), indicating a worse functional impairment when compared to individuals with normal vitamin D levels. Additionally, patients with vitamin D deficiency had worse postural balance according to the Mann-Whitney test (P = 0.03). CONCLUSION: Vitamin D deficiency is associated with worse severity, functional status, and postural balance in patients with OA.

Association of interleukin-6 gene polymorphism (rs1800796) with severity and functional status of osteoarthritis in elderly individuals.

Osteoarthritis (OA) is the most prevalent disease of the musculoskeletal system and it has an important genetic component. Despite several reports have shown the involvement of pro-inflammatory cytokine such as interleukin-1ß and TNF-α, the role of interleukin-6 (IL-6) in osteoarthritis is still unclear. Thus, this study aimed to analyze the relationship between the single nucleotide polymorphism in the portion -572 of the promoter region of the IL6 gene (SNP -572G/C) with hip and knee OA in the elderly. In this case-control study, 257 physically independent elderly were recruited (case group: 92 individuals with osteoarthritis and control group: 165 individuals with no osteoarthritis). Blood samples were collected from patients for the DNA fragments extraction and amplification by real-time polymerase chain reaction (PCR) by TaqMan system for subsequent genotyping of IL6 gene. The degree of joint damage was assessed by radiographic classification based on the criteria of Kellgren and Lawrence. The functional status was evaluated by Lequesne and WOMAC questionnaires. It was observed that individuals carrying the C allele have lower susceptibility to osteoarthritis (OR=0.51, 95% CI: 0.32-0.80, p=0.004) and less radiological impairment for both hip (Fisher-Freeman-Halton test=4.2 and p=0.04) and knee joints (Fisher-Freeman-Halton test=4.7 and p=0.03). Regarding functional status, individuals carrying the C allele has a lower degree of functional impairment assessed by WOMAC (Mann-Whitney test, p=0.04), although no difference was observed in the Lequesne questionnaire (p>0.05). Additionally, it was observed a marked reduction in IL-6 serum levels in individuals with GC and CC genotypes when compared to individuals harboring GG genotype. In conclusion, the polymorphism -572G/C IL6 is a protective factor for the presence and severity of hip and knee osteoarthritis in the elderly. Further prospective studies with large sample size and methods (e.g. effect of this polymorphism on gene expression, haplotype analysis for IL-6 promoter polymorphism) are needed to validate this study findings.

Age-related changes in the global DNA methylation profile of leukocytes are linked to nutrition but are not associated with the MTHFR C677T genotype or to functional capacities.

Global DNA methylation of peripheral blood leukocytes has been recently proposed as a potential biomarker for disease risk. However, the amplitude of the changes in DNA methylation associated with normal aging and the impacts of environmental changes on this variation are still unclear. In this context, we evaluated the association of global DNA methylation with nutritional habits, tobacco smoking, body mass index (BMI), clinical laboratory parameters, polymorphism C677T MTHFR, functional cognition and the daily practice of physical activity in a cancer-free older population. Leukocyte global DNA methylation from 126 older individuals was quantified using a high-throughput ELISA-based method. Global DNA hypomethylation was observed in older individuals when compared to a younger population (p = 0.0469), confirming changes in DNA methylation in the aging process. Furthermore, the methylation profile of elders was correlated with the daily ingestion of carbohydrates (p = 0.0494), lipids (p = 0.0494), vitamin B6 (p = 0.0421), magnesium (p = 0.0302), and also to the serum levels of total protein (p = 0.0004), alpha 2 globulin (p = 0.0013) and albumin (p = 0.0015). No statistically significant difference was observed when global DNA methylation were stratified according to C677T MTHFR genotypes (p = 0.7200), BMI (p = 0.1170), smoking habit (p = 0.4382), physical activity in daily life (p = 0.8492), scored cognitive function (p = 0.7229) or depression state (p = 0.8301). Our data indicate that age-related variations in the global DNA methylation profile of leukocytes might be modulated by the daily intake of carbohydrates, lipids, vitamin B6, and magnesium and be associated with serum protein levels, however it is independent of C677T MTHFR genotype and not correlated with BMI, smoking habit, cognitive function or the routine physical activities.