Vitamin D Status and Its Associated Risk Factors among Adults in the Southwest Region of Cameroon

Exploring the impact of vitamin D on tendon health: a comprehensive review

Tendons are vital components of the musculoskeletal system, facilitating movement and supporting mechanical loads. Emerging evidence suggests that vitamin D, beyond its well-established role in bone health, exerts significant effects on tendon physiology. The aim of this manuscript is to review the impact of vitamin D on tendons, focusing on its mechanisms of action, clinical implications, and therapeutic applications. A comprehensive search of scientific electronic databases was conducted to identify articles on the effects of vitamin D on tendon health. Fourteen studies were included in this review. Five studies were performed in vitro, and nine studies were conducted in vivo. Despite some conflicting results, the included studies showed that vitamin D regulates collagen synthesis, inflammation, and mineralization within tendons through its interaction with vitamin D receptors. Epidemiological studies link vitamin D deficiency with tendon disorders, including tendinopathy and impaired healing. Supplementation with vitamin D shows promise in improving tendon strength and function, particularly in at-risk populations such as athletes and the elderly. Future research should address optimal supplementation strategies and explore the interplay between vitamin D and other factors influencing tendon health. Integrating vitamin D optimization into clinical practice could enhance tendon integrity and reduce the burden of tendon-related pathologies.

Association of circulating serum free bioavailable and total vitamin D with cathelicidin levels among active TB patients and household contacts

The free hormone hypothesis postulates that the estimation of free circulating 25 (OH)D may be a better marker of vitamin D status and is of clinical importance compared to total vitamin D fraction. The unbound fraction is involved in biological activities since it is able to penetrate into the cell. Studies have shown that cathelicidin/LL-37 inhibits the growth of Mycobacterium tuberculosis in a vitamin D-dependent manner and therefore adequate vitamin D is required for its expression. The study aimed to determine the association between serum bioavailable and total vitamin D with LL-37 levels in ATB patients, LTBI, and individuals with no TB infection. This was a cross-sectional study in which bioavailable vitamin D and LL-37 levels were measured using competitive ELISA kits and total vitamin D was measured using electrochemilumiscence and consequently determined their association. The mean (SD) bioavailable vitamin D levels of the study participants were 3.8 ng/mL (2.6) and the median (IQR) of LL-37 levels were 320 ng/mL (160, 550 ng/mL). The mean (SD) of total vitamin D levels was 19.0 ng/mL (8.3) ng/mL. Similar weak correlations were observed between the bioavailable and total vitamin D with LL-37 levels, therefore, deviating from our hypothesis.

Ionised and total hypocalcaemia in pregnancy: An analysis of prevalence and risk factors in a resource-limited setting, Cameroon

INTRODUCTION

Hypocalcaemia remains a prevalent laboratory finding in pregnancy, capable of inducing adverse maternofoetal outcomes. This study compares the prevalence of hypocalcaemia in apparently healthy pregnant women from the ionised, and total calcaemia viewpoints and further identifies factors associated with total crude and ionised hypocalcaemia in pregnancy.

METHODS

A hospital-based cross-sectional study was conducted between November 2020 and September 2021, targeting apparently healthy pregnant women received in late pregnancy in four maternities in the Nkongsamba Health District, Cameroon. Blood samples were collected and analysed for serum ionised calcium concentrations and pH (by ion-selective electrode potentiometry), and for total calcium and albumin concentration (by atomic absorption spectrophotometry). Sociodemographic, obstetric and nutritional data were collected using an interviewer-administered questionnaire.

RESULTS

The average age of the 1074 participants included in the study was 28.20±6.08 years. The prevalence of total crude and total albumin-corrected hypocalcaemia in this study was 61.64 [58.69-64.50]% and 56.70 [53.72-59.64]%, respectively (p-value = 0.000). The prevalence of ionised hypocalcaemia was very low (2.89 [2.04-4.07]%) compared with the prevalence of total hypocalcaemia (p-value = 0.000). Monthly income below 100.000FCFA (179 USD) (AOR = 0.73, p-value = 0.024), taking more than 2 meals daily (AOR = 0.68, p-value = 0.006) and taking desserts (AOR = 0.73, p-value = 0.046) reduced the odds of total crude hypocalcaemia, while having banana/plantain and tubers as the content of their most consumed meal significantly increased the odds of total crude hypocalcaemia (AOR = 1.37, p-value = 0.012). Single women (AOR = 2.54, p-value = 0.021), with a higher education (AOR = 3.27, p-value = 0.017), who initiated antenatal care before 4 months (AOR = 2.47, p-value = 0.029), had their odds of ionised hypocalcaemia significantly increased. On the other hand, women below 30 years (AOR = 0.44, p-value = 0.039), with occupations other than housewife (AOR = 0.34, p-value = 0.027), and women who took desserts between meals (AOR = 0.45, p-value = 0.034) had their odds of ionised hypocalcaemia significantly reduced. Taking calcium supplements simultaneously with other supplements also significantly reduced the odds of total hypocalcaemia in pregnancy (OR = 0.69, p-value = 0.027).

CONCLUSION

Ionised hypocalcaemia in pregnancy is a rare finding. Only 2.89% of all apparently healthy pregnant women have ionised hypocalcaemia in late pregnancy, while 56.70% have total hypocalcaemia. Factors like the daily number of meals, taking of desserts, the content of the most consumed meal and monthly revenue significantly affect the prevalence of total hypocalcaemia in pregnancy. On the other hand, factors like age above 30 years, having a higher education, being single, having initiated antenatal care before 4 months of pregnancy, being a housewife and not taking desserts between meals have a significantly positive association with ionised hypocalcaemia.

Hypovitaminosis D among newly diagnosed pulmonary TB patients and their household contacts in Uganda

An estimated one billion people globally live with hypovitaminosis D. Studies have indicated that vitamin D deficiency is a risk factor for active tuberculosis (TB) disease. The aim of this study was to determine the association between vitamin D deficiency and TB status among patients with active TB, latent TB infection (LTBI) and those without TB infection. In a cross-sectional study of active TB patients, LTBI, QuantiFERON GOLD testpositive and (QFN+TST+) household contact and controls QuantiFERON GOLD testnegative (QFN-TST-) samples vitamin D levels were compared. Vitamin D status was determined by measurement of total vitamin D levels with 56 samples of active TB patients, 17 with LTBI, and 22 without TB infection using electrochemiluminescence. The median interquartile range (IQR) age of the study participants was 28 (20-35) years, and the majority (63%) were females. The median (IQR) vitamin D levels were 18 ng/ml (14-24). All groups had vitamin D hypovitaminosis with significantly lower levels among active TB patients (17 ng/ml, 13, 2) than among LTBI individuals (23 ng/ml 16-29) and those without TB infection (22 ng/ml, 17-28).

Prevalence and Predictors of Hypovitaminosis D in Ethiopian HIV-Infected Adults

Background

Hypovitaminosis D is associated with bone fracture and cardiovascular disease in patients receiving antiretroviral therapy. Currently, there are few data on the magnitude of hypovitaminosis D in people living with HIV in Sub-Saharan country. Therefore, the present study determines the magnitude of hypovitaminosis D in people living with HIV and its associated factors in Ethiopia.

Methods

A cross-sectional study was conducted among 171 adult people living with HIV at Debre Berhan Specialized Hospital. Serum vitamin D was measured. Multivariate logistic regression analysis and p-value <0.05 was used to identify the associated factors of hypovitaminosis D.

Results

In the present study, the prevalence of hypovitaminosis D was 129/171 (75.4%), with 11/171 (6.4%) having vitamin D deficiency and 118/171 (69%) having vitamin D insufficiency. Female sex was significantly associated with hypovitaminosis D (AOR: 3.01, 95% CI = 1.381–6.561, P = 0.006).

Conclusion

Our study found a high burden of hypovitaminosis D among adult people living with HIV on antiretroviral therapy. Female sex was associated with hypovitaminosis D.

Vitamin D and associated factors, among pregnant women in southeastern Nigeria

In this prospective study on vitamin D and its associated factors conducted on 256 pregnant women from Anambra state of southeastern Nigeria, Vitamin D deficiency (VDD) occurred in 36 (14.1%). Vitamin D levels were significantly associated with parity, gestational age, social class, place of abode, skin colour, workplace location, and compliance to ANC drugs. Pregnant women with these features are considered to be at risk for vitamin D deficiency. The study however did not show any association between vitamin D and maternal age, social class of the pregnant women, and the season of the year. It is recommended that vitamin D supplementation be considered routinely for women with the risk factors - especially for the grandmultipara, women at term gestational age, women of dark complexion, those with indoor work location, and of urban habitat.Impact statementWhat is already known on this subject? Vitamin D is a fat-soluble vitamin primarily responsible for calcium and phosphorous homeostasis in the human body. it is derived in the human body both from endogenous sources through cutaneous synthesis following exposure to sunlight, and from endogenous conversion from pre-vitamin D to 25-hdroxycholecalciferol (25 (OH)D. Vitamin D is essential in pregnancy for maternal health, foetal skeletal growth and bone development. Vitamin D deficiency (VDD) in pregnancy occurs globally with a prevalence of 4.7% to as high as 80%.What do the results of this study add? This study shows that parity, gestational age, social class, place of domicile, skin colour, workplace location, and compliance to ANC drugs constitutes associated factors to vitamin D levels.What are the implications of these findings for clinical practice and/or further research? These findings imply that grandmultiparous pregnant women, women at term gestational age, of dark complexion, with indoor work location, and of urban habitat, by virtue of their relatively lower levels of vitamin D, should be considered for routine vitamin D supplementation.

Vitamin D Status of Adults in the Community, in Outpatient Clinics, in Hospital, and in Nursing Homes in the West of Ireland

BACKGROUND

Approximately 1 billion people worldwide have Vitamin D deficiency. The aim of this study was to compare Vitamin D status and serum 25-hydroxyvitamin D (25(OH)D) concentrations among adults sampled in the community, in outpatient clinics, as hospital inpatients and in nursing homes in the West of Ireland. The secondary aim was to determine the associations between length of hospital stay (inpatients) at the time of serum 25(OH)D sampling and Vitamin D status.

METHODS

A cross-sectional study was carried out. Patients who had serum 25(OH)D analysis carried out in Galway University Hospitals (January 2011-December 2015) were identified following interrogation of the electronic laboratory data system. Baseline demographics, location, and date of sample collection were recorded. Vitamin D deficiency was defined as a serum 25(OH)D concentration <25 nmol/L.

RESULTS

In total, 24,302 patient samples were eligible for inclusion: community 15,319; outpatient clinics 6,371; inpatients 2,339; and nursing home residents 273. Vitamin D deficiency was more common in nursing home residents than inpatients, or those sampled in outpatient clinics or in the community (42% vs 37% vs 17% vs 13%; p < .001). Inpatients sampled further into their hospital stay (≥3 days) had greater Vitamin D deficiency than inpatients sampled on 0-2 days (p = .007). Season (p < .001), sex (p < .001), and age (p < .001) were associated with 25(OH)D concentrations. Vitamin D deficiency was more common in Winter/Spring, in males, and in those aged ≥80 years.

CONCLUSIONS

Nursing home residents and inpatients are at the highest risk for Vitamin D deficiency. Season, sex, age, and day of hospital stay on which serum 25(OH)D concentrations were sampled were associated with Vitamin D status.

Developing a Model for Prediction of Serum 25-Hydroxyvitamin D Level: The Use of Linear Regression and Machine Learning Methods

OBJECTIVE

Because vitamin D status affects many organs and tissues of the body, it is important to determine the factors affecting it. The purpose of this study was to develop a model for predicting the serum 25-hydroxyvitamin D [25(OH)D] level in healthy young adults.

METHOD

This cross-sectional study was conducted on 201 healthy individuals aged 20 to 40 years old in Shiraz, Iran. Data regarding demographic characteristics, vitamin D intake through supplements, and sun exposure habits were gathered. Serum 25(OH)D concentration was also measured. Data were analyzed with R software using linear regression and different machine learning methods such as conditional tree, conditional forest and random forest.

RESULTS

Based on the linear regression, male sex (p < 0.001), taking 50,000 IU vitamin D₃ supplement monthly (p < 0.001), and lower waist circumference (p = 0.018) were identified as effective factors in increasing serum 25(OH)D levels. According to the conditional tree, taking 50,000 IU vitamin D₃ supplement monthly (p < 0.001) and sex (p < 0.001) were two main factors in the classification of individuals in terms of serum 25(OH)D levels. Besides, conditional forest and random forest results showed that the most important variable was taking 50,000 IU vitamin D₃ supplement monthly.

CONCLUSIONS

Supplement use is the first and most important predictor of 25(OH)D levels and other factors, including sex and waist circumference, are ranked thereafter, and the importance of these factors is greater in those who do not take vitamin D₃ supplements.

Prevalence of and Risk Factors for Hypovitaminosis D in Patients with Rotator Cuff Tears

Backgroud

It has been reported that vitamin D may play an important role in rotator cuff tears. However, there has been limited information about the prevalence of and risk factors for hypovitaminosis D in patients with rotator cuff tears. Therefore, the purpose of current study was to investigate the prevalence of and risk factors for hypovitaminosis D in patients with rotator cuff tears.

Methods

One hundred seventy-six patients (age, 61.9 ± 8.90 years) who underwent arthroscopic rotator cuff repair for a full-thickness tear were enrolled in this retrospective study. Preoperative serum vitamin D levels (25-hydroxyvitamin D) were measured. Hypovitaminosis D was defined as a serum concentration of 25-hydroxyvitamin D < 20 ng/mL. We investigated whether age, sex, height, weight, body mass index, bone mineral density, alcohol consumption, smoking status, and outdoor occupation were associated with hypovitaminosis D.

Results

The prevalence of hypovitaminosis D in patients with rotator cuff tears was 44.3% (78/176). The mean serum concentration of 25-hydroxyvitamin D of total patients was 24.7 ± 13.7 ng/mL. A higher serum level of vitamin D was significantly associated with older age (p < 0.001). Young age was an independent risk factor for hypovitaminosis D. The prevalence of hypovitaminosis D was also lower in patients with an outdoor occupation than in those with an indoor occupation (19.0% vs. 31.4%, p = 0.001).

Conclusions

The prevalence of hypovitaminosis D in patients with rotator cuff tears was 44.3%. Age had a significant positive correlation with the serum concentration of 25-hydroxyvitamin D. Young age and indoor working were independent risk factors for hypovitaminosis D in patients with rotator cuff tears. Therefore, the possibility of hypovitaminosis D should be considered for young and indoor working patients who have rotator cuff tears.

Vitamin D status influences transcriptional levels of RANKL and inflammatory biomarkers which are associated with activation of PBMC

Vitamin D status is involved in the risk of many chronic diseases including cancer, inflammatory and autoimmune disease. The RANK/RANKL/OPG system is also implicated in the orchestration of immune functions. We aimed to investigate the expression of RANKL, OPG and markers of inflammation and immune activation in peripheral blood mononuclear cells (PBMC) from healthy subjects with different 25(OH)D3 plasma levels. The 25(OH)D3 plasma concentrations were assessed by HPLC. The gene expression was evaluated by qRT-PCR. The expression of CYP27B1 was lower in subjects with 25(OH)D3 levels below 50 nmol/L (deficiency) than subjects with both insufficient and sufficient levels of 25(OH)D3. In subjects with deficiency, we observed the up-regulation of RANKL, TNF-α, IFN-γ, ICAM and LFA-1, and a reduction of the anti-inflammatory cytokines IL-13 and IL-4 in comparison to other subjects. Finally, we found a negative correlation between RANKL mRNA levels and 25(OH)D3 and between 25(OH)D3 and ICAM mRNA levels. A positive correlation between ICAM and RANKL was observed. Our results give evidence of the modulatory effects of circulating 25(OH)D3 levels on gene expression of biomarkers of immune activation in PBMC, suggesting the possible use of PBMC as ex-vivo model to characterize molecular mechanisms of immune/inflammatory response in hypovitaminosis conditions.