New developments in calcium and vitamin D metabolism

Association between serum 25-hydroxyvitamin D concentrations and depressive symptoms in an older Korean population: A cross-sectional study

BACKGROUND

This study aims to examine associations between serum 25-hydroxyvitamin D [25(OH)D] concentrations and depressive symptoms in an older Korean population.

METHODS

The study used data from the Korean Urban Rural Elderly study, which enrolled 2942 participants aged 65 years or older from urban and rural communities. After excluding those treated with antidepressants, we conducted cross-sectional analysis of 2853 participants (962 men and 1891 women). Serum 25(OH)D was analyzed as both a continuous and categorized variable. Depressive symptoms were assessed using the Korean version of the Geriatric Depression Scale - Short Form. Multivariate logistic regression analyses were conducted to examine relationships between serum 25(OH)D and depressive symptoms for men and women separately.

RESULTS

In men, ORs (95% CIs) for depressive symptoms were 1.74 (0.85, 3.58), 2.50 (1.20, 5.18), and 2.81 (1.15, 6.83) for those with a 25(OH)D concentration of 20.0-29.9, 10.0-19.9, and <10.0ng/mL, respectively (P-trend=0.013), compared with those with a 25(OH)D concentration of ≥30.0ng/mL, after adjustment for study year, month of assay, age, parathyroid hormone, body mass index, number of comorbidities, smoking status, alcohol intake, exercise, sleep duration, income, education, cohabitation status, and residential area. In women, the associations between 25(OH)D and depressive symptoms were significant neither before nor after adjustment.

LIMITATIONS

Due to the cross-sectional study design, causal association is uncertain. Intake of vitamin D supplements and outdoor activity were not examined.

CONCLUSIONS

Our findings suggest that lower concentrations of vitamin D are independently associated with depressive symptoms in older Korean adults.

The association between serum 25-hydroxyvitamin D concentrations and depressive symptoms in Korean adults: findings from the fifth Korea National Health and Nutrition Examination Survey 2010

The aims of this study were to examine the association between circulating vitamin D (25(OH)D) levels and depressive symptoms and to evaluate the associations between depressive symptoms and various sociodemographic factors. Data on serum 25(OH)D levels, sociodemographic factors, and information on depressive symptoms were obtained from the Korea National Health and Nutrition Examination Survey V-1 2010. A total of 3,570 Koreans aged ≥20 years were included in the statistical analysis. Subjects with depressive symptoms had lower serum levels of 25(OH)D (41.6±16.2 nmol/L) than those without (44.3±16.2 nmol/L; P-value<0.05; effect size = 0.17). In a logistic regression analysis, the 25(OH)D sufficiency group (≥50 nmol/L) revealed fewer depressive symptoms (OR, 0.72; 95% CI, 0.53-0.97; P-value = 0.032) after adjusting for multiple factors. In addition, females (OR, 3.61; 95% CI, 2.55-5.11; P-value<0.001), problematic alcohol users (OR, 2.33; 95% CI, 1.63-3.34; P-value<0.001), current smokers (OR, 1.43; 95% CI, 1.02-1.99; P-value = 0.036), and subjects who experienced weight loss (OR, 1.78; 95% CI, 1.30-2.44; P-value<0.001) were more likely to answer "yes" on question for depressive symptoms. In conclusion, low serum levels of 25(OH)D were associated with an increased risk for depression symptoms in Korean adults. In addition, several sociodemographic factors were related to the depressive symptoms. Our results provide insight into the relationships among vitamin D status, sociodemographic factors, and depression in the Korean population.

Renal osteodystrophy: a pediatric perspective, 2005

Renal osteodystrophy (ROD) associated with chronic kidney disease (CKD) involves a complex interrelationship of the loss of divalent mineral homeostasis, hyperparathyroidism, and gene modulation. In affected children, ROD leads to impaired linear growth as well as to the development of other significant skeletal and extraskeletal manifestations. Despite the success of kidney transplantation, many ROD complications cannot be completely reversed; and thus, patients with CKD and ROD require long-term follow-up. Although the availability of vitamin D analogues has advanced ROD management, it has also created new issues for clinicians to address, motivating future investigations of calcimimetic therapies. An algorithmic approach to the management of ROD in children is presented; to be most effective, this approach requires close and frequent surveillance to prevent side effects related to potent therapies.

The loss of Smad3 results in a lower rate of bone formation and osteopenia through dysregulation of osteoblast differentiation and apoptosis

Smad3 is a well-characterized intracellular effector of the transforming growth factor beta (TGF-beta) signaling pathway and was implicated recently in the potentiation of vitamin D receptor (VDR)-mediated signaling. Given that both TGF-beta and vitamin D are important regulators of bone remodeling, it is expected that Smad3 plays an integral role in normal maintenance of bone. However, the exact mechanisms by which Smad3 functions in bone remodeling are unknown. Here, we show that mice with targeted deletion of Smad3 are osteopenic with less cortical and cancellous bone compared with wild-type littermates. Decreases in bone mineral density (BMD) in Smad3 null mice reflect the inability of osteoblasts to balance osteoclast activity, although osteoclast numbers are normal and vitamin D mediated serum calcium homeostasis is maintained. The osteopenia of Smad3 null mice is attributed to a decreased rate of bone formation associated with increased osteocyte number and apoptosis. These findings are supported by studies with isolated primary osteoblasts that show TGF-beta can no longer inhibit the differentiation of osteoblasts in the absence of Smad3; yet, TGF-beta-stimulated proliferation remains intact. Together these data support a model that a loss of Smad3 increases the osteocyte fate of the osteoblast and decreases the duration of osteoblast function by shortening lifespan, ultimately resulting in osteopenia.