UNASSIGNED: Prior reports have indicated an inconsistent relationship between vitamin D levels and myopia in children and adolescents with limited sample size. This study was undertaken to further clarify this relationship with a repeated cross-section study.
UNASSIGNED: The National Health and Nutrition Examination Survey (NHANES) database with samples <19 years old was utilized. Data on rates of myopia (spherical equivalent less than or equal to -1.0 D), serum 25-hydroxyvitamin D [25(OH)D] level (high performance liquid chromatography), and other key variables were extracted and analyzed. Three models were utilized to evaluate the dose response of vitamin D levels using stepwise logistic regression. Logistic regressions for sex subgroups and other covariates were also performed, and Forest plots were drawn.
UNASSIGNED: Data were available from 6,814 children (49.5% girls; mean age: 14.9±1.85 years). The myopia and non-myopia differed in serum 25(OH)D level, gender, race, poverty income ratio (PIR), and body mass index (BMI). Serum 25(OH)D levels were negatively correlated with myopia [odds ratio (OR) =0.98, 95% confidence interval (CI): 0.77-0.99, P<0.05] regardless of sex. Although the relationship did not appear to be linear, there was a dose effect with higher serum 25(OH)D levels linked with lower rates of myopia. In addition, rates of myopia were increased in females compared with males (OR =1.12, 95% CI: 1.01-1.24, P=0.03), those with a high PIR (OR =1.08, 95% CI: 1.04-1.11, P<0.001), and those with high BMI (OR =1.19, 95% CI: 1.11-1.27, P<0.001). White ethnicity (OR =0.78, 95% CI: 0.68-0.90, P<0.001) and leisure-time exercise (OR =0.94, 95% CI: 0.92-0.97, P=0.02) were associated with lower rates of myopia.
UNASSIGNED: These findings indicate that higher serum 25(OH)D levels and increased amounts of leisure-time exercise are associated with lower rates of myopia in this group of children and adolescents. Meanwhile, female gender, high PIR level, and high BMI were associated with greater rates of myopia. The findings indicated that children and adolescents needed leisure-time exercise to lower the risk of myopia.

BACKGROUND: Limited evidence exists on the relationship between vitamin D status and mortality in depressed patients.
METHODS: This study investigates serum 25-hydroxyvitamin D [25(OH)D] concentrations in 8417 adults with depression among the National Health and Nutrition Examination Survey (NHANES, 2005-2018). Mortality outcomes were assessed through National Death Index records up to December 31, 2019. Cox proportional risk models estimated risk ratios (HR) and 95 % confidence intervals (CI) for all-cause, cardiovascular disease (CVD), and cancer mortality. Restricted cubic spline analyses explored the nonlinear association of serum 25(OH)D levels with mortality, using the likelihood ratio test for nonlinearity.
RESULTS: The weighted mean serum 25(OH)D level was 66.40 nmol/L (95 % CI: 65.8, 67.0), with 36.3 % having deficient vitamin D (<50 nmol/L [20 ng/mL]). Over an average 7.16-year follow-up, 935 deaths were documented, including 296 CVD deaths and 191 cancer deaths. Higher serum 25(OH)D levels were associated with reduced all-cause mortality (HRs 0.55-1.00, p trend = 0.006) and cancer-specific mortality (HRs 0.36-1.00, p trend = 0.015) after multivariate adjustment. The relationship between serum 25(OH)D and all-cause mortality exhibited a nonlinear pattern (P for nonlinearity <0.001), with a 34 % lower risk for each unit increase in natural log-transformed 25(OH)D levels. Significant interactions were observed with age, antidepressant use, and diabetes status.
CONCLUSIONS: Higher serum 25(OH)D levels were associated with decreased all-cause and cancer-specific mortality in depressed adults, particularly among younger individuals and those using antidepressants or without diabetes. Further research is essential to understand mechanisms and interventions related to vitamin D in depression.

Patients with familial hypokalemic periodic paralysis (HOKPP) experience episodes of reversible immobility and are at an increased risk of limited sunlight exposure, potentially leading to vitamin D deficiency. However, there is a lack of data on vitamin D levels in this population. We investigated serum vitamin D levels and their associated factors in children with HOKPP. This study included 170 genetically-confirmed children with HOKPP, aged 3-18 years, and 170 age-, sex-, and body mass index (BMI)-matched healthy controls from the Korean Channelopathy Study, a prospective controlled investigation. Anthropometric and clinical characteristics were recorded, and serum levels of calcium, ionized calcium, phosphorus, alkaline phosphatase, 25-hydroxyvitamin D, and intact parathyroid hormone (PTH) were analyzed. Vitamin D deficiency (< 20 ng/mL) was observed in 87.0% of the patients compared to 45.5% of the controls (P < 0.05) during the summer-fall season. During the winter-spring season, 91.7% of the patients and 73.4% of the controls were deficient (P < 0.05). A strong positive correlation was found between onset age of the first paralytic attack and vitamin D levels (r = 0.78, P < 0.01). Conversely, the frequency and duration of paralytic attacks were negatively correlated with vitamin D levels (r = -0.82 and r = -0.65, P < 0.01, respectively). Age, BMI, age at onset, frequency and duration of attacks, and PTH levels were independently associated with vitamin D levels (ß = -0.10, -0.12, 0.19, -0.27, -0.21, and -0.13, P < 0.05, respectively).
CONCLUSIONS: Vitamin D deficiency was highly prevalent in children with HOKPP, and vitamin D levels correlated with various disease characteristics. We recommend routine screening for vitamin D levels in these patients to address this prevalent deficiency. Considering the high prevalence of vitamin D deficiency observed, further research on other diseases characterized by reversible immobility is warranted.
BACKGROUND: • A correlation between immobility and low serum vitamin D levels has been established. However, the vitamin D status of patients with familial hypokalemic periodic paralysis (HOKPP) who experience periods of reversible immobility remains unknown.
BACKGROUND: • Vitamin D deficiency was highly prevalent in children with HOKPP, and vitamin D levels correlated with various disease characteristics.

BACKGROUND: The comparatively low 25 hydroxyvitamin D [25(OH)D] levels have been reported in patients with metabolic syndrome (MetS). Herein we investigated the cross-sectional and longitudinal relationships between serum 25(OH)D levels and MetS risk profile in northern middle-aged Chinese subjects without vitamin D supplementation.
METHODS: A cohort of 211 participants including 151 MetS patients and 60 controls at 20-69 years of age were enrolled from suburban Beijing, China. The recruited MetS patients were subjected to diet and exercise counselling for 1-year. All subjects at baseline and MetS patients after intervention underwent clinical evaluations.
RESULTS: Serum 25(OH)D levels were significantly decreased in MetS patients. 25(OH)D levels were inversely related to MetS score, fasting blood glucose (FBG) and triglyceride-glucose index (TyG) after adjusting for cofounders (all P < 0.05). Participants in the lowest tertile of 25(OH)D levels had increased odds for MetS (P = 0.045), elevated FBG (P = 0.004) in all subjects, and one MetS score gain in MetS patients (P = 0.005). Longitudinally, the metabolic statuses as well as 25(OH)D levels of MetS patients were significantly improved (all P < 0.05), and the increase of 25(OH)D levels were inversely related to MetS scores, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), FBG, and TyG, while positively related to high-density lipoprotein cholesterol (HDL-C) after adjusting for confounders.
CONCLUSIONS: 25(OH)D levels were significantly decreased in MetS patients, and it was negatively associated with metabolic dysfunctions at baseline and 1-year after. Metabolic aberrations of MetS patients were significantly ameliorated with 1-year follow-up counselling accompanying by notably elevated 25(OH)D levels.

BACKGROUND: Vitamin D deficiency is considered to be a global health problem. The purpose of this study was to evaluate the prevalence of vitamin D deficiency and analyze its related factors among adult residents in Hainan, a tropical island province of southern China.
METHODS: A total of 1,700 healthy adults, aged 18-86 years (617 men and 1,073 women), were enrolled in our cross-sectional descriptive study. Binomial logistic regression analyses were performed to identify possible predictors of vitamin D status.
RESULTS: The average serum 25-hydroxyvitamin D [25(OH)D] concentration was 37.66±10.77 ng/mL (males 43.60±11.8 ng/mL, females 34.20±8.40 ng/mL; I<0.001). The proportions of vitamin D sufficiency [25(OH)D ≥30 ng/mL], insufficiency [20 ng/mL ≤25(OH)D <30 ng/mL], and deficiency [25(OH)D <20 ng/mL] were 76.6%, 20.5%, and 2.9%, respectively. Vitamin D deficiency in the young, middle-aged, and elderly groups were 4.2%, 2.7%, and 1.7%, respectively. Vitamin D sufficiency was found to be positively associated with male sex (P<0.0001), age >40 years (P=0.014), habitation in a rural area (P<0.0001), summer/autumn seasons (P<0.0001), and having <13 years of formal education (P<0.0001).
CONCLUSIONS: Our study was the first to assess the vitamin D status and analyze related factors among adult residents in Hainan Province, China. We found that vitamin D deficiency has low prevalence in this population, suggesting that before developing a strategy for the clinical use of vitamin D supplements in a region, the levels of vitamin D in generally healthy populations of that region should be assessed, to avoid unnecessary supplementation.

Vitamin D is beneficial in patients with immune-mediated rheumatic diseases as it has been shown that it lowers the incidence risk and the level of inflammation. To examine the association between clinical outcomes and initial 25-hydroxyvitamin D [25(OH)D] concentrations in patients with the immune-mediated rheumatic diseases treated with infliximab for 9 months. This study was performed in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) treated with infliximab for at least 38 weeks. Disease activity was assessed using Disease Activity Score (DAS28) for RA and PsA and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) for AS, while the global assessment was performed using the Visual Analogue Scale (VAS). Patients were divided into 2 groups according to 25(OH)D concentration which was classified as deficient or non-deficient (below and above 50 nmol/L, respectively). Concentrations of infliximab (IFX) and C-reactive protein (CRP) were measured according to the manufacturer\'s instructions.This study was performed in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) treated with infliximab for at least 38 weeks. Disease activity was assessed using Disease Activity Score (DAS28) for RA and PsA and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) for AS, while the global assessment was performed using the Visual Analogue Scale (VAS). Patients were divided into 2 groups according to 25(OH)D concentration which was classified as deficient or non-deficient (below and above 50 nmol/L, respectively). Concentrations of infliximab (IFX) and C-reactive protein (CRP) were measured according to the manufacturer\'s instructions. The study included 23 patients (14 with RA, 6 with AS and 3 with PsA), median age 54 years, 15 females. Vitamin D deficient and non-deficient groups had median initial concentrations of 38 and 61 nmol/L, respectively. DAS28 and pain on VAS calculated at the 2nd and 38th week showed a statistically significant decrease only in RA and PsA patients with vitamin D deficiency (P = 0.02 and 0.06, respectively). Lower initial concentration of 25(OH)D in patients treated with infliximab was associated with better improvement of clinical measures (DAS28 and VAS) of disease after 9 months of therapy.

Objective: The purpose of this study was to further clarify the association of Hashimoto\'s thyroiditis (HT) and vitamin D deficiency, and to seek the connection between them and related influencing factors. Methods: Data were obtained from subjects who underwent health examinations from January 2018 to December 2018. The diagnosis of HT was based on: antithyroid peroxidase antibody (TPO-Ab) levels >35 IU/ml and/or antithyroglobulin antibody (Tg-Ab) levels >40 IU/ml. Based on the Endocrine Society guidelines, 25-hydroxyvitamin D [25(OH)D] levels ≥30.0 ng/ml were classified as a vitamin D sufficiency; those between 20 and 29.9 ng/ml, as an insufficiency; and those <20 ng/ml, as a deficiency. All statistical analysis was performed by software R. Results: Of a total of 75,436 individuals who were physically examined, 5,656 of them had 25(OH)D levels tested at the same time; 5,230 were enrolled. The level of 25(OH)D in the non-HT group was higher than that in the HT group. Multiple regression analysis showed that HT was statistically significantly correlated with being male, body mass index (BMI), waist circumference, and thyroid-stimulating hormone (TSH). TSH levels in the insufficiency group and deficiency group were higher than those in the sufficiency group. Free triiodothyronine (FT3) and thyroxine (FT4) levels in the insufficiency group and deficiency group were lower than those in the sufficiency group. 25(OH)D increased by 1 ng/ml at the normal reference level, with an increase of 2.78 ng/dl in FT4 concentration and a decrease of 0.17 mIU/L in TSH. Conclusions: Patients with HT present with a reduced 25(OH)D level, and TSH is an independent risk factor for HT. TSH is negatively correlated with 25(OH)D level. FT3 and FT4 levels were positively correlated with 25(OH)D levels.

Low vitamin D status is prevalent worldwide and has been linked to a variety of pathologies including obesity in adults. The severity of vitamin D deficiency amongst the overweight and obese Singaporeans is not well documented. The purpose of this prospective observational study was to assess the prevalence and determinants of vitamin D deficiency in a multi-ethnic Asian population referred for weight management, including those seeking bariatric surgery.
This was a cross-sectional study conducted among 111 consecutive subjects referred to a single institution weight management service in Singapore. The data collected included their anthropometric data, body mass index (BMI), body fat percentage, waist circumference, 25-hydroxyvitamin D [25(OH)D] and other bone turnover markers.
The average BMI among the 111 subjects was 40.1 ± 8.2 kg/m2 and mean age of 40 ± 10 years. Vitamin D deficiency was found in 75.7% of the population. There was a significant negative association of vitamin D with adiposity markers including BMI (r = - 0.31), body fat percentage (r = - 0.34) and waist circumference (r = - 0.26). Predictors of vitamin D deficiency included age > 50 years, female gender, waist circumference and body fat percentage.
Vitamin D deficiency is prevalent among this target population in Singapore regardless of ethnicity. In particular, the elderly, females, those with larger waist circumference and body fat percentage were significantly associated with lower serum 25(OH)D level. Hence, routine screening for the overweight and obese subjects in multi-ethnic Singapore seeking weight management is indicated.

BACKGROUND: We investigated the prevalence and risk factors for vitamin D deficiency in Korean patients with anemia.
METHODS: We included 200 anemic patients and 300 controls. Anemia was defined according to the WHO criteria. Serum 25-hydroxyvitamin D [25(OH)D] was measured using an electrochemiluminescence immunoassay. We compared serum 25(OH)D levels based on the presence and subtypes of anemia.
RESULTS: We found that 91% (182/200) and 87.3% (262/300) of patients exhibited 25(OH)D inadequacies (<20 ng/ml) in the anemic (median hemoglobin (Hb), 9.6 g/dl) and control groups (median Hb 13.8 g/dl), respectively. The prevalence of 25(OH)D deficiency (<12 ng/ml) was significantly higher in the anemic group than in the control group (52.5% (105/200) vs. 25% (75/300), P < 0.0001), with an odds ratio of 3.316 (95% CI, 2.265-4.854; P < 0.0001). The prevalence of 25(OH)D deficiency was not different among anemia subtypes. Female gender and high C-reactive protein (CRP) were associated with vitamin D deficiency in anemic group.
CONCLUSIONS: This study demonstrates that vitamin D deficiency is associated with anemia. Therefore, the measurement of serum 25(OH)D levels and appropriate vitamin D supplementation should be considered in anemic patients, particularly in females and patients with high CRP level.