High prevalence of vitamin D deficiency and influencing factors among urban and rural residents in Tianjin, China

Low serum 25-hydroxy-vitamin D levels are associated with metabolic syndrome in a representative community population from Macau, China

Asians, especially Chinese have an increasingly high prevalence of vitamin D deficiency and insufficiency (serum 25-hydroxy-vitamin D 25(OH)D < 30 nmol/L and < 50 nmol/L, respectively). This population group also has a high prevalence of cardiometabolic risk factors such as Myocardial Infarction (MI), Metabolic Syndrome (MetS) and low blood levels of high-density lipoproteins (HDL) and high blood levels of triglycerides (TG). The aim of this analysis was to investigate these associations in a population from Macau, China. Blood, anthropometric, and physical data were collected from 1410 randomly selected residents of Macau. In this population, (55 % female, 19-89 years) 54 % were vitamin D insufficient. Results from categorical multivariate regression analyses (adjusted for age, sex, and physical activity, sitting and sunlight exposure) indicated significant two-fold associations between vitamin D insufficiency and prevalence of MI, MetS and low HDL and high TG levels. These associations became stronger when investigated with vitamin D deficiency (25(OH)D < 30 nmol/L). The association between cardiometabolic factors and vitamin D deficiency in those older (≥60 yrs) increased markedly to OR MI= 9.48 (2.62-34.32), OR MetS= 7.82 (3.31-18.46) and OR low HDL= 8.68 (1.56-21.16) and OR high TG= 2.37 (1.07-5.25). These interesting observational findings suggest high vulnerability to lower 25(OH)D levels with related health disparities affecting older Asians. Integration of public health measures to detect vitamin D deficiency and insufficiency in Macau is important, and we suggest that routine health screening including serum 25(OH)D, HDL and TG in China may be protective for those at higher risk for related cardiometabolic conditions.

Comparison of vitamin D status in healthy Bangladeshi urban and rural individuals and their association with serum calcium and alkaline phosphatase: A pilot study

Vitamin D insufficiency is a worldwide problem that is likely underestimated since physical symptoms may only be apparent in individuals with severe deficiencies. Previously, people in South Asian countries were thought to be vitamin D sufficient because of plentiful sunshine, but vitamin D insufficiency has also been reported in these countries. In a South Asian country like Bangladesh, people living in the rural and urban parts of the country can have considerable differences in their sun exposure, types of clothing worn, and levels of air pollution. This pilot study aimed to explore the vitamin D status (measured by serum 25[OH]D) of healthy urban and rural Bangladeshi people and to examine the association of serum 25(OH)D concentration with calcium and alkaline phosphatase concentrations. A total of 101 apparently healthy adult individuals, aged 20-58 years, were enrolled from both urban and rural areas. The participants were selected from students, staff and patient attendants from the outpatient department (OPD) of Bangabandhu Sheikh Mujib Medical University and Mirsarai Upazila Health Complex, Chittagong. The overall rate of vitamin D insufficiency was 39.6% and of vitamin D deficiency was 51.5%. However, it was observed that the proportion of vitamin D-deficient participants in urban areas (70.6%) was more than double that of participants living in rural areas (32%) and that serum 25(OH)D concentrations were higher in rural compared to urban participants with similar sunlight exposure times. However, participants aged 50 years or more showed similar concentrations of serum vitamin D levels irrespective of their habitat. This pilot study highlights the need for further larger-scale studies in Bangladesh to determine the reasons for the high rates of vitamin D inadequacy overall and the differences between rural and urban populations.

25-Hydroxyvitamin D status does not affect energy metabolism among young, healthy, non-obese adults: a metabolic chamber study

Purpose

here is a general consensus that an inverse relationship exists between vitamin D status and body mass index (BMI) in overweight and obese individuals, leading to the hypothesis that vitamin D deficiency may contribute to the development of unfavorable metabolic phenotypes. However, evidence from non-obese adults remains limited. This study measured energy metabolism in non-obese adults using a metabolic chamber and explored its association with vitamin D status.

Methods

Sixty-nine healthy adults (mean age = 22.8 years, mean BMI = 20.7 kg/m2) participated in this cross-sectional study. Participants were categorized into vitamin D-deficient, insufficient, and sufficient groups based on the Chinese classification for total 25(OH)D levels (WS/T 677-2020). They performed typical daily activities in a metabolic chamber, where their baseline lipid profile, 24-hour energy expenditure, and substrate oxidation were measured.

Results

A two-way ANOVA (seasonality × 25(OH)D) revealed no statistically significant differences in total energy expenditure, resting energy expenditure, sleeping energy expenditure, walking energy expenditure, carbohydrate oxidation rate, or fat oxidation rate among the three groups (p > 0.05). These results remained consistent even after adjusting for fat-free mass. Although statistically significant correlations were found between 25(OH)D status and certain lipid profile markers (i.e., total cholesterol, high-density lipoprotein, and free fatty acid) (p < 0.05), these correlations were weak, with Pearson's correlation coefficients below 0.3.

Conclusions

Total 25(OH)D status does not affect energy metabolism in young, healthy, non-obese adults. Along with existing evidence, this suggests that low 25(OH)D status is more likely a consequence of unfavorable metabolic phenotypes rather than a contributing factor.

Clinical trial registration

https://www.chictr.org.cn, identifier ChiCTR-IIR-17010604.

Variation in vitamin D status in infants and children: a two-year cross-sectional study in Shanghai, China

BACKGROUND

Vitamin D deficiency (VDD) is a public health problem. The variation in vitamin D status across regions and populations remains unclear, and there is a lack of consensus regarding the screening for VDD in individuals.

METHODS

Children who visited the hospital from January 2019 to December 2020 were included in this study. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured using an enzyme-linked immunosorbent assay. The cutoffs for serum 25(OH)D concentrations to define deficiency, insufficiency, and sufficiency were < 20 ng/mL, 20-30 ng/mL, and ≥ 30 ng/mL, respectively.

RESULTS

A total of 7285 children aged 0-11 years were assessed; the mean 25(OH)D level was 31.4 ng/mL, and the median 25(OH)D level was 30.7 (interquartile range 24.4, 37.5) ng/mL. The 25(OH)D level declined with age in clinical visiting children aged 0-11 years, but maintained a consistently high level in health examination children aged 4-11 years. The percentages of 25(OH)D < 20 ng/mL and 25(OH)D < 30 ng/mL were 10.0% and 43.8%, respectively. Higher percentages of VDD were found in clinical visiting children than in health examination children within the 6-11-year group (53.3% vs. 14.7%) and winter (44.3% vs. 15.4%).

CONCLUSION

Low vitamin D status (deficiency and insufficiency) was more common in clinic-visiting children than in health examinations, especially in schoolchildren and in the winter. The study implies the positive effects of vitamin D assessments included in child health checkups to optimize vitamin D status.

Association between serum vitamin D status and the anti-seizure treatment in Chinese children with epilepsy

Objective

To compare the serum 25-OH-VitD levels, the major marker of vitamin D (VitD) status, between healthy children and children with epilepsy before initiation of and during anti-seizure medications (ASMs) treatment and to evaluate the potential influence factors on 25-OH-VitD levels. Another major aim was to assess the potential role of VitD supplementation.

Methods

For comparison, we finally enrolled and collected data from 6,338 healthy children presenting to Health Care Department and 648 children visiting primary care pediatricians with symptoms of epilepsy in Children’s Hospital of Nanjing Medical University from January 2019 to June 2021. The demographic and biochemical characteristics of each child were extracted from the hospital information system.

Results

Serum 25-OH-VitD levels in 648 children with epilepsy were significantly lower than those of 6,338 healthy children (P &lt; 0.0001), and the percentage of VitD insufficiency and deficiency status in pediatric patients was 49.19%. Of note, the serum 25-OH-VitD levels in children with newly diagnosed epilepsy before receiving any ASMs treatment were also significantly lower than those in healthy controls. Interestingly, ASMs therapy, alone or in combination, did not consistently reduce baseline serum VitD levels in children with epilepsy. The lower serum VitD levels in pediatric patients than those in healthy children might be related to the disease itself, rather than the ASMs treatment. As expected, VitD supplementation substantially increased the serum 25-OH-VitD levels (P &lt; 0.0001). More critically, children with epilepsy receiving VitD supplementation achieved good seizure control in our study.

Significance

In this retrospective study, the childhood epilepsy before initiation of and during ASMs treatment decreased the serum 25-OH-VitD concentrations, suggesting a clear association between epileptic disease and the risk of VitD deficiency. ASMs coadministration and long-term valproic acid treatment did not worse VitD-deficiency status, but in the small group receiving VitD supplementation, there was a significant improvement in reduction of seizure frequency. Therefore, pediatric clinicians are urged to raise public awareness of epilepsy-associated VitD deficiency.

Relationship between serum vitamin D and hip fracture in the elderly: a systematic review and meta-analysis

INTRODUCTION

This study investigated the relationship between serum 25-hydroxyvitamin D (25OHD) levels and the occurrence of hip fractures in the elderly using a systematic review and meta-analysis approach.

MATERIALS AND METHODS

PubMed, Web of Science, and Scopus were used to identify studies that outlined an association between serum 25OHD and the occurrence of a hip fracture in a geriatric patient. The analysis calculated odds ratios (OR) for a hip fracture using a random-effects model.

RESULTS

In this study, 28 studies were included, 61,744 elderlies and 9767 cases (15.81%) of hip fractures. In the lowest vs. highest categories of vitamin D in the elderly, pooled OR of hip fractures was 1.80 (95% CI 1.56-2.07, P ≤ 0.001), and modified OR was equal to 1.40 (95% CI 1.20-1.63 P ≤ 0.001). A subgroup analysis showed that the OR of a hip fracture was 2.16 (1.49-3.11, P ≤ 0.001) in case-control studies; 1.52 (1.29-1.79, P = 0.001) in cohort studies; and 1.41 (1.18-1.70, P ≤ 0.001) in case-cohort studies.

CONCLUSION

Low serum vitamin D levels in the elderly are associated with an increase in the odds of hip fracture.

Vitamin D deficiency is associated with thyroid autoimmunity: results from an epidemiological survey in Tianjin, China

PURPOSE

The pathogenesis of Hashimoto's thyroiditis (HT) is unclear, although some studies have identified an association between vitamin D deficiency and thyroid autoantibody positivity. This study aimed to investigate vitamin D status, and its relationships with thyroid autoantibody positivity and HT, via a large epidemiological survey.

METHODS

The epidemiological survey was conducted in Tianjin, China. All participants underwent testing for serum 25-hydroxyvitamin D (25OHD), thyroid function, and thyroid autoantibodies, and some participants underwent testing to evaluate CD4⁺ T-cell differentiation and concentrations of related cytokines.

RESULTS

The study included 1812 participants and revealed prevalences of 13.1% for thyroid peroxidase antibodies (i-TPOAb) and 14.0% for thyroglobulin antibodies (i-TgAb). Logistic regression analysis revealed that thyroid autoantibody positivity was associated with sex, age, and 25OHD classification. An increased likelihood of i-TPOAb positivity was associated with 25OHD deficiency (odds ratio [OR]: 2.428, 95% confidence interval [CI]: 1.383-4.261) and 25OHD inadequacy (OR: 1.198, 95% CO: 0.828-1.733; p = 0.008). An increased likelihood of i-TgAb positivity was associated with 25OHD deficiency (OR: 2.366, 95% CI: 1.366-4.099) and 25OHD inadequacy (OR: 1.263, 95% CI: 0.883-1.807; p = 0.009). Relative to healthy subjects, patients with HT had significantly higher proportions of Th1 and Th17 cells, as well as higher concentrations of related cytokines.

CONCLUSIONS

This study revealed that vitamin D deficiency was associated with thyroid autoantibody positivity, and that vitamin D deficiency seems to be involved in the pathological mechanism underlying HT. Large randomized controlled trials are needed to investigate the effects of vitamin D supplementation on HT.

Frequency and determinants of vitamin D deficiency among premenopausal and postmenopausal women in Karachi Pakistan

Background

Vitamin D deficiency is becoming a serious public health problem, even in sun-drenched cities like Karachi, Pakistan. We investigated the prevalence of vitamin D deficiency and its association with sociodemographic characteristics, anthropometric measures, and lifestyle factors among premenopausal and postmenopausal women (n = 784).

Methods

Face-to-face interviews were conducted to collect information and serum concentrations of 25-hydroxyvitamin D were measured after the interviews.

Results

A total of 57% of women were vitamin D deficient with higher vitamin D deficiency found among premenopausal women (64.7%) compared to postmenopausal women (49%). The median serum concentrations of 25-hydroxyvitamin D (IQR) were 16.7 ng/ml (IQR 9.8–30.0). Factors associated with vitamin D deficiency were lower socioeconomic status (OR 2.00; 95% CI 1.15–3.48), younger age with highest vitamin D deficiency found in < 35 years of age group (OR 3.11; 95% CI 1.76–5.51), and winter season (OR 1.51, 95% CI 1.07–2.15) after adjusting for multiple confounders. The use of vitamin D supplement (OR 0.59, 95% CI 0.38–0.92) and vigorous exercise (OR 0.20, 95% CI 0.05–0.80) were protective against vitamin D deficiency.

Conclusions

The study shows a high prevalence of vitamin D deficiency, with detrimental health effects, among younger women belonging to lower socioeconomic status and during the winter season. The use of vitamin D supplements and vigorous exercise were protective measures. Public health campaigns are needed for education and awareness about vitamin D deficiency to improve vitamin D status for younger women living in poor environments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-021-01339-9.

Correlation between 25-hydroxyvitamin D level and arterial elasticity in middle-aged and elderly cadres in Guiyang, China: A retrospective observational study

There is evidence that serum 25-hydroxyvitamin D [25-(OH) D] levels may be associated with cardiovascular disease and its risk factors. This study aimed to investigate the relationship between 25-(OH) D levels and blood pressure (BP), blood lipids, and arterial elasticity in middle-aged and elderly cadres in China.In this retrospective study, we included 401 civil servants and cadres aged >42 years who underwent medical examinations at Guiyang Municipal First People's Hospital, China in 2018. The participants were assigned to deficiency (≤20 ng/mL), insufficiency (20-30 ng/mL), and sufficiency (≥30 ng/mL) groups according to 25-(OH) D levels in their blood. Demographics, brachial-ankle pulse wave velocity (baPWV), BP, ankle-brachial index (ABI), and blood lipids were compared among groups. The associations between 25-(OH) D and other parameters were evaluated using linear regression analysis.Median (range) 25-(OH) D levels in the deficiency (n = 162), insufficiency (n = 162), and sufficiency (n = 77) groups were 15.32 (2.93-19.88), 25.12 (20.07-29.91), and 33.91 (30.23-82.42) ng/mL, respectively. There were significant differences in systolic BP, pulse pressure, baPWV (left and right sides), ABI (left side), high-density lipoprotein-cholesterol, and triglycerides (TGs; all P < .05) among groups. Multivariate linear regression revealed that TG, left baPWV, and right baPWV were significantly negatively correlated with 25-(OH) D levels (all P < .05).In this study, 25-(OH) D levels were found to be associated with TG, left baPWV, and right baPWV values. 25-(OH) D deficiency may be associated with reduced arterial elasticity.

Poor Status of Vitamin D: A Survey of Area With Lowest Sunlight Radiation in Sichuan, China

OBJECTIVE

Vitamin D plays an important role in bone and mineral metabolism. Ultraviolet B (UVB) is the primary determinant for vitamin D synthesis. However, population-based data of vitamin D status was sparse in areas with sunlight deprivation in China. This study aimed to assess serum 25-hydroxyvitamin D [25(OH)D] levels among adult women in Sichuan basin with the lowest sunlight radiation in China, and the associations with sunlight exposure and age.

METHODS

In the context of the same ethnicity, similar latitude and lifestyle in sunlight-limited basin and sunlight-abundant plateau, 1,057 women in basin and 337 in plateau aged 29-95 years were included in this study, from November 2012 to February 2013. Daily sunlight exposure duration of previous month was obtained using questionnaires. Serum 25(OH)D was measured by enzyme-linked immunosorbent assay.

RESULTS

The prevalence of vitamin D severe deficiency [25(OH)D <30 nmol/L] and deficiency [30 ≤ 25(OH)D <50 nmol/L] was significantly higher in basin than plateau (21.85% vs. 10.09%, and 59.32% vs. 40.36%; P<0.0001). Women from basin exhibited lower serum 25(OH)D levels than those from plateau (40.66 ± 15.62 vs. 52.54 ± 19.94 nmol/L, P<0.0001). In basin, women more than 50 years old had higher 25(OH)D than younger counterparts, and 25(OH)D level of these groups was not associated with sunlight exposure duration. While in plateau, women younger than 60 years old had higher 25(OH)D than the older women. Furthermore, for those younger groups, women with long sunlight exposure (≥3 h daily) had higher 25(OH)D concentration than those with short sunlight exposure (<3 h daily). Serum PTH was negatively associated with 25(OH)D in basin, but not in plateau.

CONCLUSIONS

Alarmingly high prevalence of vitamin D deficiency was observed in women in sunlight-deprived basin in Sichuan. Only the vitamin D status of younger women from plateau with adequate solar radiation could benefit from sunlight exposure. Vitamin D supplementation and vitamin D-fortified food should be encouraged to improve vitamin D status for women living in sunlight-limited areas, or with old age.

A Nonlinear Relationship Between Serum 25-Hydroxyvitamin D and Urine Albumin to Creatinine Ratio in Type 2 Diabetes: A Cross-Sectional Study in China

BACKGROUND

Diabetic kidney disease often presents as increased urine albumin to creatinine ratio (UACR). 25-hydroxyvitamin D (25(OH)D) is considered as the best indicator of vitamin D status. Previous studies have shown that 25(OH)D is related to the UACR. However, evidence concerning the connection between 25(OH)D and UACR is still limited in the Chinese population.

MATERIALS AND METHODS

A total of 549 participants with type 2 diabetes were enrolled in the study from Shenzhen People's Hospital, China. The participants were grouped by the tertiles of 25(OH)D level. The association between 25(OH)D and UACR was examined by multiple linear regression. A generalized additive model (GAM) was used to verify a non-linear relationship. We conducted a subgroup analysis to evaluate the robustness of the results.

RESULTS

After adjusting for relevant variables, 25(OH)D was negatively correlated with UACR (β = -8.7, 95% CI (-12.0, -5.4)). A non-linear relationship was discovered between 25(OH)D and UACR, and the 25(OH)D threshold was 67. The effect sizes and confidence intervals on the left and right sides of the inflection point were -13.9 (-18.2, -9.6) and 8.9 (-1.1, 18.9), respectively. Subgroup analysis showed a stronger correlation could be detected in males. The same trend also could be found in patients older than 70 years old, those with using ACEI/ARB, with history of hypertension, with SBP ≥140 mmHg and eGFR <60 mL/min/1.73m².

CONCLUSION

The relationship between 25(OH)D and UACR is non-linear. 25(OH)D was negatively related to UACR when 25(OH)D is less than 67 nmol/L.

Vitamin D Status and Survival in Stage II-III Colorectal Cancer

Vitamin D status has been shown to be positively correlated with the morbidity and prognosis of colorectal cancer (CRC) patients. However, the prognostic effect of vitamin D status on patients with stage II and III CRC, especially Asian patients, remains unclear. A total of 728 patients (523 in the primary cohort and 205 in the validation cohort) who were diagnosed with stage II-III CRC between January 2011 and December 2015 were enrolled. Their serum 25-hydroxyvitamin D3 [25(OH)D] levels were tested. Kaplan-Meier curves and Cox regression analyses were carried out. Subgroup analyses were conducted according to tumor location. In the primary cohort, the serum 25(OH)D level was positively correlated with the overall survival (OS) of all CRC patients (p= 0.016) and stage III patients (p= 0.009), while no correlation was found between 25(OH)D level and the prognosis of patients with stage II CRC. Moreover, 25(OH)D level was an independent prognostic factor for the OS of all patients with CRC [HR 0.541, 95% CI 0.334-0.875, p=0.012] and those with stage III CRC (HR 0.563, 95% CI 0.319-0.993, p=0.047). Subgroup analysis indicated that only in the left-sided subgroup, stage III CRC patients with high 25(OH)D levels had better OS than those with low 25(OH)D levels (HR 0.474, 95% CI 0.230-0.978, p=0.043). In the validation cohort, serum 25(OH)D levels were verified to have prognostic value for patients with stage III CRC (HR 0.220, 95% CI 0.080-0.602, p=0.003), and low 25(OH)D levels indicated worse OS for left-sided stage III CRC patients (HR 0.233, 95% CI 0.075-0.727, p=.012). In conclusion, vitamin D status is positively correlated with the survival of CRC patients, especially those with left-sided stage III CRC.

Meteorological Condition and Air Pollution Exposure Associated with Vitamin D Deficiency: A Cross-Sectional Population-Based Study in China

Objective

The aim of this study was to investigate the status of Vitamin D deficiency and the effect of environmental factors on Vitamin D levels so as to provide theoretical support for public health promotion in this region.

Methods

A total of 22,387 subjects who underwent a physical examination at the center in the West China Hospital, Sichuan University, between April, 2018 and May, 2020 were enrolled in this study. Their data on gender, age, inspection date, serum 25 hydroxyvitamin D (25-(OH) D), parathyroid hormone (PTH), and total calcium were retrospectively reviewed. Next, the percentage of Vitamin D status was compared in different sex and age groups, and the fluctuation of Vitamin D level was described in relation to the change of environment. Finally, the univariable and multivariable linear regression analyses were performed to explore the risk and protective factors of Vitamin D deficiency.

Results

The proportion of Vitamin D deficiency in this area was 42.17%, and it was significantly higher among women and young people. The fluctuation trend of 25-(OH) D levels are consistent with temperature and solar radiation, and opposite to air quality, in the whole year. There was a positive relationship between 25-(OH) D levels with temperature and solar radiation; however, parathyroid hormone, female and AQI were negatively correlated with Vitamin D levels.

Conclusion

Vitamin D deficiency is common in subtropic areas, such as Sichuan Basin, which is related to solar radiation and air pollution.

Serum 25 hydroxyvitamin D levels and affecting factors among preconception fertile women

Background

Recent study found that vitamin D before conception was considered as a potential additional determinant for achieving pregnancy and live births. The study aimed to evaluate the serum 25 hydroxyvitamin D (25(OH)D) levels and its affecting factors among preconception fertile women.

Methods

This cross-sectional study enrolled 410 women aged 22–44 years who attended a preconception genetic counseling clinic from January 2018 to May 2019. Sociodemographic characteristics and reproductive history of women were collected, and height and weight were measured. Serum 25(OH)D concentration was assayed with chemiluminescence immunoassay. Descriptive statistics were used to examine serum 25(OH)D concentration, and socio-demographic characteristics and reproductive history among preconception women. Determinants of vitamin D deficiency and its affecting factors were assessed using χ2 test and logistic regression.

Results

Findings showed 84.4% of women had serum 25(OH)D concentration below 20 ng/mL. Women working indoors as well as without a history of childbirth had significantly lower 25(OH)D levels compared with those non-working individuals and having delivered a previous child (both P < 0.05). The 25(OH)D levels were the lowest in winter among that in spring, summer, and autumn (all P < 0.001). Women in winter have significantly elevated OR of 5.00 (95%CI 1.75–14.25) to develop vitamin D deficiency. Seasonal variation in serum 25(OH)D levels was not present in non-working individuals and women aged 31–44 years.

Conclusions

Vitamin D deficiency is common among preconception women especially nulliparous women and working women, which propose to screen serum 25(OH)D on preconception evaluation and emphasize need vitamin D supplements and get sunshine exposure.

Vitamin D and PTH: data from a cross-sectional study in an equatorial population

OBJECTIVE

Investigate the prevalence of vitamin D deficiency in an equatorial population through a large-sample study.

METHODS

Cross-sectional study with 30,224 healthy individuals from the North Region, in Brazil (Amazônia - state of Pará), who had 25-hydroxy-vitamin D (25(OH)D) and intact parathyroid hormone (PTH) serum levels measured by immunoassay method. Those with history of acute or chronic diseases were excluded. Abnormal levels of calcium, creatinine, glycemia and albumin were also exclusion criteria.

RESULTS

25(OH)D levels were 29.1 ± 8.2 ng/mL and values <12.7 ng/mL were equal to < -2 s.d. below average. Hypovitaminosis D was present in 10% of subjects according to the Institute of Medicine (values <20 ng/mL) and in 59%, in consonance with Endocrine Society (values 20-30 ng/mL as insufficiency and <20 ng/mL as deficiency) criteria. Individuals were divided according to four age brackets: children, adolescents, adults and elderly, and their 25(OH)D levels were: 33 ± 9; 28.5 ± 7.4; 28.3 ± 7.7; 29.3 ± 8.5 ng/mL, respectively. All groups differed in 25(OH)D, except adolescents vs adults. Regression model showed BMI, sex, living zone (urban or rural) and age as independent variables to 25(OH)D levels. Comparing subjects with vitamin D deficiency (<20 ng/mL) to those with vitamin D insufficiency (20-30 ng/mL), a difference between PTH levels in these two groups was observed (95.9 ± 24.7 pg/mL vs 44.2 ± 64.5 pg/mL; P < 0.01). Additionally, the most accurate predictive vitamin D level for subclinical hyperparathyroidism in ROC curve was 26 ng/mL.

CONCLUSION

Our equatorial population showed low prevalence of vitamin D hypovitaminosis ranging with age bracket. The insufficient category by Endocrine Society was corroborated by our PTH data.

Sleep duration is associated with vitamin D deficiency in older women living in Macao, China: A pilot cross-sectional study

Chinese women are known to have both a high prevalence of metabolic syndrome (MetS) and vitamin D deficiency (serum 25-hydroxyvitamin D (25OHD) <50 nmol/l). Associations between sleep duration and circulating 25OHD have recently been reported but, to our knowledge, these associations have not been studied in older Chinese populations. We thus investigated whether sleep duration was associated with vitamin D status in a population from Macao, China, and whether sleep duration modified the association between MetS and vitamin D deficiency. In 207 older (>55 years) Macanese, anthropometry, blood samples and validated questionnaires, including sleep duration and cardiovascular risk factors, were simultaneously collected. On multivariable categorical analyses, those women, not men, who had short sleep duration (≤6 hours (h)) were at a 2-fold risk for vitamin D deficiency (both <50 nmol/L and <37 nmol/L; OR = 1.94, 95%CI 1.29–2.92; OR = 2.05, 95%CI 1.06–3.98, respectively) and those who had longer sleep duration (>8 h) were 3-fold more likely to have vitamin D deficiency (OR = 3.07, 95%CI 1.47–6.39; OR = 2.75, 95%CI 1.08–7.00, respectively) compared to those with normal sleep duration (6–8 h). Both women and men with MetS were 2-fold more likely to have vitamin D deficiency (women: OR = 2.04, 95%CI 1.31–3.17; OR = 2.15, 95%CI 1.11–4.17, respectively; men: OR = 2.01, 95%CI 1.23–3.28; OR = 2.04, 95%CI 1.00–4.29, respectively). Moreover, women with both short sleep duration and MetS had an increased risk of vitamin D deficiency (OR = 3.26, 95%CI 1.10–9.64). These associations were not found in those with longer sleep. Men with longer sleep and MetS had a 5-fold risk of vitamin D deficiency (OR = 5.22; 95%CI 2.70–10.12). This association was non-significant for men with shorter sleep. We conclude that both short and long sleep duration were associated with vitamin D deficiency in older Chinese women. Further research is needed in larger cohorts or with intervention studies to further examine the associations between reduced sleep, metabolic syndrome and vitamin D deficiency.

Higher risk of vitamin D insufficiency/deficiency for rural than urban dwellers

There are many risk factors for Vitamin D deficiency. This study aimed to compare the Vitamin D status and serum 25(OH)D concentrations of adults living in an urban area to adults living in a rural area in the West of Ireland (latitude 53.27° North). A cross-sectional retrospective analysis of clinical records was performed. Following interrogation of the electronic laboratory information system, individuals who had serum 25(OH)D concentrations measured at Galway University Hospitals between January 2011 and December 2015 were identified. Clinical demographics, setting and date of sampling were recorded. In total, 17,590 patients (urban n = 4,824; rural n = 12,766) were eligible for inclusion. Serum 25(OH)D concentrations were lower among rural compared to urban dwellers irrespective of season (spring p < 0.001, summer p = 0.009, autumn p = 0.002, winter p < 0.001). There was a significant difference in Vitamin D status between urban and rural dwellers in three of the four seasons: spring- deficiency: 16%-v-23%, insufficiency: 39%-v-43%, sufficiency: 45%-v-35% (p < 0.001); autumn- deficiency: 11%-v-10%, insufficiency: 30%-v-35%, sufficiency: 59%-v-56% (p = 0.01); winter- deficiency: 23%-v-25%, insufficiency: 35%-v-42%, sufficiency: 41%-v-33% (p < 0.001). Serum 25(OH)D concentrations were higher and the prevalence of deficiency lower in urban/rural females compared to urban/rural males (p < 0.001). Serum 25(OH)D concentrations increased sequentially from the 18-39 year age group to the 60-69 year age group in both urban (p < 0.001) and rural (p < 0.001) dwellers and then decreased progressively as age increased to ≥90 years. The odds of Vitamin D deficiency increased with age, lower daily sunshine hours, male gender, rural address and season.

Aqueous humor and serum 25-Hydroxyvitamin D levels in patients with cataracts

Background

Serum 25-hydroxyvitamin D (25 (OH) D) levels are associated with various pathologic ocular conditions. Few studies have assessed 25 (OH) D concentrations in non-serum specimens, and none to date has assessed 25 (OH) D concentrations in human aqueous humor and their association with ocular diseases. This study investigated the possible correlations between 25 (OH) D concentrations in aqueous humor and serum and whether vitamin D concentrations in aqueous humor were associated with cataract.

Methods

This study prospectively enrolled 136 patients, including 87 with senile cataract and 49 with diabetic cataract, who underwent cataract surgery from January to November 2017. 25 (OH) D was measured in aqueous humor and serum specimens collected from all patients, and their correlation was analyzed statistically. Clinical and laboratory data, including the results of ophthalmologic examinations, were compared in the two groups of cataract patients.

Results

No correlation was observed between 25 (OH) D concentrations in aqueous humor and serum (P = 0.381). 25 (OH) D concentrations in aqueous humor were significantly higher in patients with diabetic than senile cataract (P = 0.006). Multivariate logistic regression analysis showed that the adjusted odds ratio for diabetic cataract for the highest compared with the lowest quartile of 25 (OH) D concentration in aqueous humor was 4.36 ng/ml (95% confidence interval [CI]: 1.33–14.34 ng/ml; P = 0.015). Multivariate linear regression analysis showed that 25(OH) D concentration in aqueous humor was 2.68 ng/ml (95% CI: 0.34–5.01 ng/ml; P = 0.025) higher in patients with diabetic than senile cataract.

Conclusions

25(OH) D concentrations in aqueous humor and serum did not correlate with each other. Higher 25(OH) D level in aqueous humor was associated with diabetic cataract. These findings suggest that studies of vitamin D levels in patients with ocular conditions should include measurements of vitamin D levels in aqueous humor.

The Association of Serum Vitamin D Deficiency and Metabolic Risk Factors in Chinese Adults with Prediabetes: A Cross-Sectional Study

The association of serum vitamin D deficiency and metabolic risk factors in Chinese adults with prediabetes (PreDM) has not been investigated. The present study aimed to investigate the association of serum vitamin D deficiency and metabolic risk factors in Chinese adults with PreDM. In this cross-sectional study, we stratified 412 PreDM patients into vitamin D sufficient, vitamin D insufficient and vitamin D deficient subgroups. The physical examination data was collected. Serum 25-hydroxyvitamin D₃ [25(OH)D₃] were measured by high performance liquid chromatography. The prevalence of vitamin D deficiency and insufficiency in PreDM patients were 30.58% and 26.70%, respectively. Compared with the vitamin D deficient group, the prevalence of metabolic syndrome, central obesity, hyperglycemia and hypertension were higher than those in the vitamin D insufficient or sufficient group (p<0.05). Moreover, the prevalence of dyslipidemia in the vitamin D deficient group was higher than those in the vitamin D sufficient group (p<0.05). We observed an inverse relationship between 25(OH)D₃ levels and waist circumference, triglyceride, and serum uric acid (β=-0.315; β=-0.134; β=-0.239), a positive relationship between 25(OH)D₃ levels and high-density lipoprotein cholesterol (β=0.197) after adjusting for age, sex and body mass index. Vitamin D deficiency is very common among PreDM patients in China and this deficiency is related to metabolic risk factors.