Serum vitamin D and sex hormones levels in men and women: The Multi-Ethnic Study of Atherosclerosis (MESA)

Gestational vitamin D and offspring fracture risk: do associations persist into mid adolescence?

BACKGROUND

Previous studies report that maternal vitamin D exposure during pregnancy is associated with offspring later-life bone health. A study in the Vitamin D in Pregnancy (VIP) cohort reported sexually dimorphic effects of maternal 25-hydroxyvitamin-D (25(OH)D) and offspring fracture profiles at 10 years of age. We, therefore, aimed to determine associations between maternal 25(OH)D status and offspring fracture risk at 16 years of age in this cohort.

METHODS

In total, 475 mother-child pairs were recruited to the VIP study in southeastern Australia. Maternal serum samples were obtained at recruitment (<16 weeks' gestation) and/or 28-32 weeks' gestation and analysed for 25(OH)D. Radiologically-confirmed incident fractures in children were ascertained from date of birth (2002-2004) until July 16, 2019. Cox proportional hazard models were used to determine associations between maternal 25(OH)D and childhood fracture risk, and final models included maternal age at recruitment, offspring sex, birth weight, gestation length and season of 25(OH)D sample.

RESULTS

Data were available for 400 children (mean age 16.1 years). There were 122 (30.5%) children who sustained at least one fracture. Higher maternal 25(OH)D (per 10 nmol/L) in early gestation was associated with a decreased fracture risk in boys (HR 0.87; 95% CI: 0.77, 0.99); the pattern was reversed in girls (HR 1.10; 95% CI 1.00, 1.22). At late gestation, higher maternal 25(OH)D was associated with an increased fracture risk in girls (HR 1.14; 95% CI: 1.04, 1.24).

CONCLUSIONS

While our findings must be interpreted within the constraints of our limitations, we report that the contradictory risk profiles observed at early childhood in this cohort remain in adolescence.

Effects of vitamin D on sex steroids, luteinizing hormone, and testosterone to luteinizing hormone ratio in 307 infertile men

OBJECTIVE

Vitamin D status has been associated with sex steroid production. The question is whether vitamin D supplementation has an impact on sex steroid production in infertile men with vitamin D insufficiency?

DESIGN

A single-center, double-blinded, randomized clinical trial. Differences in sex steroids and reproductive hormones were predefined secondary outcomes, vitamin D status at baseline was a predefined subgroup and the primary outcome was differences in semen quality.

METHODS

A total of 307 infertile men were included and randomized 1:1 to active or placebo treatment for 150 days. Men in the active group initially received an oral bolus of 300,000 IU cholecalciferol, followed by daily supplementation with 1400 IU cholecalciferol and 500 mg calcium.

RESULTS

After intervention, no differences were found in serum concentrations of sex steroids, luteinizing hormone, testosterone/luteinizing hormone ratio or SHBG between the vitamin D and placebo group. However, in a predefined subgroup analysis of men with serum 25OHD ≤ 50 nmol/L, men treated with vitamin D had a significantly higher testosterone/luteinizing hormone ratio [4.2 (3.8-4.4) vs. 3.7 (3.4-4.0); p = 0.033] compared with placebo treatment. In men with vitamin D deficiency, the difference between groups was larger but not significant due to few men with serum 25OHD < 25 nmol/L.

CONCLUSION

Vitamin D + calcium supplementation did not alter sex steroid production in infertile men. However, vitamin D insufficient men treated with vitamin D supplementation had a significantly higher testosterone/LH ratio compared with placebo-treated men, suggesting that optimal Leydig cell function are dependent on adequate vitamin D status.

Vitamin D and potential effects on cancers: a review

Cancer is characterized by the abnormal and uncontrollable division and growth of cells that can infiltrate tissues and alter normal physiological function, which will become crucial and life-threatening if left untreated. Cancer can be a result of genetics, such as mutations or environmental causes, including smoking, lack of physical activity, as well as nutritional imbalance in the body. Vitamin D is one of the foremost nutrients that play a crucial role in a variety of biochemical pathways, and it is an important key factor in several diseases. Vitamin D is an essential nutrient for preventing malignancies and a complementary treatment for cancer through direct and indirect biochemical pathways. In this article, we summarized the correlation between vitamin D and various cancers using an extensive search on PubMed, Google Scholar, and Scopus. This paper reviews the role of vitamin D in different types of cancer.

Vitamin D and suicidality: a Chinese early adolescent cohort and Mendelian randomization study

AIMS

Previous cross-sectional and case-control studies have proposed that decreased vitamin D levels are positively correlated with the risk of suicidality in adults. However, limited studies have examined the association between vitamin D and suicidality in adolescents. This study aimed to investigate the relationship between serum vitamin D and suicidality risk among early adolescents.

METHODS

Data were obtained from a Chinese early adolescent cohort. In this cohort, seventh-grade students from a middle school in Anhui Province were invited to voluntarily participate in the baseline assessments and provide peripheral blood samples (in September 2019). The participants were followed up annually (in September 2020 and September 2021). Serum 25-hydroxyvitamin D [25(OH)D] and vitamin D-related single-nucleotide polymorphisms at baseline were measured in November 2021. Traditional observational and Mendelian randomization (MR) analyses were performed to examine the relationship between serum 25(OH)D at baseline and the risk of baseline and incident suicidality (i.e., suicidal ideation [SI], plans and attempts).

RESULTS

Traditional observational analysis did not reveal a significant linear or non-linear association of serum 25(OH)D concentration with the risks of baseline and 2-year incident suicidality in the total sample (P > .05 for all). Sex-stratified analysis revealed a non-linear association between the 25(OH)D concentration and the risk of baseline SI in women (Poverall = .002; Pnon-linear = .001). Moreover, the risk of baseline SI in the 25(OH) insufficiency group was lower than that in the 25(OH) deficiency group in the total sample (odds ratio [OR] = 0.69, 95% confidence interval [CI] = 0.51-0.92, P = .012). This difference remained significant in women (OR = 0.59, 95% CI = 0.40-0.87, P = .008) but not in men (OR = 0.78, 95% CI = 0.53-1.15, P = .205). Additionally, both linear and non-linear MR analyses did not support the causal effect of serum 25(OH)D concentration on the risk of baseline, 1-year and 2-year incident suicidality (P > .05 for all).

CONCLUSIONS

This study could not confirm the causal effect of vitamin D on suicidality risk among Chinese early adolescents. Future studies must confirm these findings with a large sample size.

Association Between 25-hydroxyvitamin D Levels and Testosterone in Healthy, Non-Obese, Young Adult, Filipino Men

Objective

This study seeks to determine the association between vitamin D and testosterone in healthy, adult Filipino males.

Methodology

This cross-sectional study included 110 healthy, non-obese, male volunteers aged 21-40. History and physical exam were taken, and blood was drawn for vitamin D, total testosterone (TT), sex hormone binding globulin (SHBG), albumin, insulin, fasting plasma glucose, and total cholesterol. Free testosterone (FT) was calculated. Vitamin D data were classified by status and TT, FT, and SHBG levels compared using the Kruskal-Wallis test. The associations of vitamin D levels with TT, FT, and SHBG were explored using multiple regression analysis.

Results

Vitamin D levels were sufficient in 3 (2.7%), insufficient in 17 (15.45%), and deficient in 90 (81.8%) of the sample. There were no significant differences in the mean TT (p = 0.7981), FT (p = 0.8768), nor SHBG (p = 0.1838) across vitamin D status. Vitamin D was not associated with TT nor FT before or after adjustment for age and age plus body mass index (BMI). Vitamin D was associated with SHBG before and after the aforementioned adjustments, but this became insignificant on sensitivity analysis.

Conclusion

There is no association between vitamin D and TT, FT nor SHBG in our cohort with deficient vitamin D levels.

Decreased Vitamin D Levels and Altered Placental Vitamin D Gene Expression at High Altitude: Role of Genetic Ancestry

High-altitude hypoxia challenges reproduction; particularly in non-native populations. Although high-altitude residence is associated with vitamin D deficiency, the homeostasis and metabolism of vitamin D in natives and migrants remain unknown. We report that high altitude (3600 m residence) negatively impacted vitamin D levels, with the high-altitude Andeans having the lowest 25-OH-D levels and the high-altitude Europeans having the lowest 1α,25-(OH)2-D levels. There was a significant interaction of genetic ancestry with altitude in the ratio of 1α,25-(OH)2-D to 25-OH-D; with the ratio being significantly lower in Europeans compared to Andeans living at high altitude. Placental gene expression accounted for as much as 50% of circulating vitamin D levels, with CYP2R1 (25-hydroxylase), CYP27B1 (1α-hydroxylase), CYP24A1 (24-hydroxylase), and LRP2 (megalin) as the major determinants of vitamin D levels. High-altitude residents had a greater correlation between circulating vitamin D levels and placental gene expression than low-altitude residents. Placental 7-dehydrocholesterol reductase and vitamin D receptor were upregulated at high altitude in both genetic-ancestry groups, while megalin and 24-hydroxylase were upregulated only in Europeans. Given that vitamin D deficiency and decreased 1α,25-(OH)2-D to 25-OH-D ratios are associated with pregnancy complications, our data support a role for high-altitude-induced vitamin D dysregulation impacting reproductive outcomes, particularly in migrants.

Differential effects of vitamin D on upper and lower body fat-free mass: potential mechanisms

Vitamin D insufficiency is a global health concern and low vitamin D status is regularly associated with reduced muscle mass and sarcopenia in observational research. Recent research using Mendelian randomization (MR) has highlighted the potentially causal positive effect of serum vitamin D (25(OH)D) on total, trunk and upper body appendicular fat-free mass (FFM). However, no such effect was found in lower body FFM, a result that mirrors the outcomes of some vitamin D intervention studies. Here we review the current literature on vitamin D, muscle mass and strength and discuss some potential mechanisms for the differing effects of vitamin D on upper and lower body FFM. In particular, differences in distribution of the vitamin D receptor as well as androgen receptors, in the upper and lower body musculature, will be discussed.

Association of a low vitamin D status with risk of post-stroke depression: A meta-analysis and systematic review

Background

Although post-stroke depression (PSD) affects one-third of patients following an acute stroke, pooled evidence addressing the correlation between a low vitamin D status and the risk of PSD remains inconclusive.

Methods

Comprehensive database search of Medline, EMBASE, Cochrane library, and Google Scholar was performed from inception to December 2022. The primary outcome was the association of PSD risk with a low vitamin D status, while the secondary outcomes included the relationship between PSD and other risk factors.

Results

Analysis of seven observational studies published between 2014 and 2022 with 1,580 patients showed pooled incidences of vitamin D deficiency (defined as 25[OH] D levels < 50 nmol/L) and PSD of 60.1 and 26.1%, respectively. Patients with PSD had a lower circulating vitamin D concentration compared to those without [mean difference (MD) =-13.94 nmol/L, 95% CI: -21.83 to -6.05, p = 0.0005, I ² = 91%, six studies, 1,414 patients]. Meta-analysis also demonstrated a correlation between a low vitamin D level and an increased PSD risk [odd ratio (OR) = 3.25, 95% CI: 1.57-6.69, p = 0.001, I ² = 78.7%, 1,108 patients], the heterogeneity of which was found to be associated with the incidence of vitamin D deficiency but not female proportion on meta-regression. Besides, female gender (OR = 1.78, 95% CI: 1.3-2.44, p = 0.003, I ² = 31%, five studies, 1,220 patients), hyperlipidemia (OR = 1.55, 95% CI: 1.01-2.36, p = 0.04, I ² = 0%, four studies, 976 patients), and high National Institutes of Health Stroke Scale (NIHSS) scores (MD = 1.45, 95% CI: 0.58-2.32, p = 0.001, I ² = 82%, five studies, 1,220 patients) were potential risk factors for PSD. For the primary outcome, the certainty of evidence was very low. Regarding secondary outcomes, the certainty of evidence was low for BMI, female gender, hypertension, diabetes, and stroke history, and very low for age, level of education, hyperlipidemia, cardiovascular disease, and NIHSS scores.

Conclusion

The results suggested an association of a low circulating vitamin D level with an increased risk of PSD. Besides, female gender, hyperlipidemia, high NIHSS score were related to an increased risk or occurrence of PSD. The current study may imply the necessity of routine circulating vitamin D screening in this population.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022381580.

The Association between Vitamin D and the Components of Male Fertility: A Systematic Review

OBJECTIVE

Previous systematic reviews of the effects of vitamin D on the components of male fertility have been inconclusive. This article systematically reviews the latest research to examine the relationship between vitamin D, semen quality parameters, and sex hormones production.

METHODS

MEDLINE, Cochrane, and Web of Science databases were searched using the appropriate keywords.

RESULTS

Observational studies indicate significant correlation between vitamin D levels and sperm parameters, with a particular emphasis on sperm motility, and partially suggest a relationship between higher serum testosterone and vitamin D levels. Additionally, interventional studies confirmed that vitamin D supplementation has a positive effect on sperm motility, especially progressive. However, most randomized clinical trials indicate that vitamin D treatment does not have any significant effect on testosterone or other hormone levels.

CONCLUSIONS

Although our findings add to the discussion regarding the effect of vitamin D on male fertility, there is still no solid evidence to support the use of vitamin D supplementation to improve the outcomes of patients with impaired sperm parameters and hormonal disorders. Additional dedicated clinical studies are needed to clarify the relationship between vitamin D and male fertility, along with its components.

Sex differences in vitamin D metabolism, serum levels and action

The ubiquity of vitamin D metabolising enzymes and vitamin D receptors in mammalian organisms suggests that vitamin D has pleiotropic effects. There are quite a few studies indicating the anticancer, cardioprotective and antidiabetic effects of vitamin D; however, the best-documented actions of vitamin D are the regulation of Ca-phosphate balance and its effect on immune function.Vitamin D levels in organisms are modulated by many environmental and non-environmental factors. One potential factor that may influence vitamin D levels and effects is the sex of the individuals studied. This review focuses on the scientific evidence indicating different synthesis and metabolism of vitamin D in females and males, mainly from PubMed database sources. The article verifies the sex differences in vitamin D levels reported around the world. Moreover, the different effects of vitamin D on the musculoskeletal, cardiovascular, nervous and immune systems, as well as cancer in males and females, were discussed.Most studies addressing sex differences in vitamin D levels and effects are observational studies with conflicting results. Therefore, carefully designed clinical trials and experiments on animal models should be carried out to determine the role of non-environmental factors that may differentiate vitamin D levels in females and males.

Gender-related differences in the association of serum levels of vitamin D with body mass index in northern Iranian population: the PERSIAN Guilan Cohort Study (PGCS)

BACKGROUND

Vitamin D (VD) insufficiency has now become a global problem throughout the world. The association between increasing body mass index (BMI) and VD insufficiency has attracted great attention in recent researches. The aim was to study if BMI was independently associated with serum 25-hydroxy VD in a large population-based study, specify by gender.

METHODS

Data on 9520 adults 35 years and older participating in PERSIAN Guilan Cohort Study (PGCS) were used. Serum levels of 25-hydroxy VD less than 20 ng/mL (50 nmol/L) was used as a measure of VD inadequacy. Multiple logistic and linear regression analyses were used to estimate the strength of the association between VD and BMI before and after adjusting for demographic factors and lifestyle variables.

RESULTS

After adjustment in male population, overweight (adjusted OR = 1.2, P < 0.05) and obese (adjusted OR = 1.4, P > 0.05) individuals were more likely to have VD inadequacy than normal weight counterparts. Moreover, there was a weak inverse linear association between BMI and serum 25 (OH) D levels in males (β = -0.14, P value > 0.05). In contrast, no significant associations between BMI and serum 25 (OH (D levels were observed in females. In male population, higher BMI were associated with lower serum vitamin 25 (OH) D levels.

CONCLUSIONS

However, association between BMI and VD level was not observed in female population. The suggestion of current study for public health was special consideration to serum VD levels in over weight and obese males.

Association of serum 25-hydroxyvitamin D with metabolic disturbances in adolescents

OBJECTIVES

Data concerning the association of vitamin D with metabolic disturbances in adolescents are contradictory. The aim of this study was to identify metabolic abnormalities in adolescents with 25-hydroxyvitamin D (25[OH]D) deficiency and to determine informative indices for the early detection of these metabolic disturbances.

METHODS

A cross-sectional observational study including 90 adolescents aged 13-15 years was carried out during the winter. Anthropometric measures were collected. Fasting blood samples were assessed for the following parameters: serum 25(OH)D, lipids, and glucose.

RESULTS

The majority of the study adolescents had low 25(OH)D concentration. The prevalence of 25(OH)D deficiency (<12 ng/ml) and insufficiency (12-20 ng/ml) in adolescents was 34.4% and 55.6%, respectively. Among the metabolic disturbance, hypo-high-density lipoprotein cholesterolemia prevailed in the adolescents, while hypercholesterolemia, hypertriglyceridemia, and hyperglycemia were rare. 25(OH)D status showed an association with the metabolic score for insulin resistance (METS-IR, r = -0.40; p < .001), high-density lipoprotein cholesterol level (r = 0.31; p = .003), atherogenic index of plasma (r = -0.30; p = .004) and body mass index (r = -0.23, p = .032). There were no significant correlations between 25(OH)D level and other lipid or glucose levels. The degree of hypovitaminosis D affects METS-IR values.

CONCLUSIONS

25(OH)D deficiency in the studied adolescents had not yet manifested serious metabolic diseases. Of all the analyzed parameters, METS-IR was most strongly associated with 25(OH)D level and can be considered a useful marker of early metabolic disturbances in adolescents with 25(OH)D deficiency.

The effect of antiretroviral therapy initiation on vitamin D levels and four oral diseases among Kenyan children and adolescents living with HIV

OBJECTIVES

The impact of antiretroviral treatment (ART) on the occurrence of oral diseases among children and adolescents living with HIV (CALHIV) is poorly understood. The aim of this study was to determine the effect of ART timing on vitamin D levels and the prevalence of four oral diseases (dry mouth, dental caries, enamel hypoplasia, and non-herpes oral ulcer) among Kenyan CALHIV from two pediatric HIV cohorts.

METHODS

This nested cross-sectional study was conducted at the Kenyatta National Hospital, Nairobi, Kenya. CALHIV, 51 with early-ART initiated at <12 months of age and 27 with late-ART initiated between 18 months-12 years of age, were included. Demographics, HIV diagnosis, baseline CD4 and HIV RNA viral load data were extracted from the primary study databases. Community Oral Health Officers performed oral health examinations following standardized training.

RESULTS

Among 78 CALHIV in the study, median age at the time of the oral examination was 11.4 years old and median ART duration at the time of oral examination was 11 years (IQR: 10.1, 13.4). Mean serum vitamin D level was significantly higher among the early-ART group than the late-ART group (29.5 versus 22.4 ng/mL, p = 0.0002). Children who received early-ART had a 70% reduction in risk of inadequate vitamin D level (<20 ng/mL), compared to those who received late-ART (p = 0.02). Although both groups had similar prevalence of oral diseases overall (early-ART 82.4%; late-ART 85.2%; p = 0.2), there was a trend for higher prevalence of dry mouth (p = 0.1) and dental caries (p = 0.1) in the early versus late ART groups. The prevalence of the four oral diseases was not associated with vitamin D levels (p = 0.583).

CONCLUSIONS

After >10 years of ART, CALHIV with early-ART initiation had higher serum vitamin D levels compared to the late-ART group. The four oral diseases were not significantly associated with timing of ART initiation or serum vitamin D concentrations in this cohort. There was a trend for higher prevalence of dry mouth and dental caries in the early-ART group, probably as side-effects of ART.

Anti-Inflammatory Effects of 1,25(OH)2D/Calcitriol in T Cell Immunity: Does Sex Make a Difference?

Hypovitaminosis D is involved in various inflammatory, infectious and autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. Moreover, the active form of vitamin D, calcitriol, has been shown to modulate the immune response, playing an anti-inflammatory effect. However little is known about the mechanisms underlying this anti-inflammatory effect and the potential sex differences of calcitriol immune regulation. Hence, the aim of this study was to investigate whether calcitriol could act differently in modulating T cell immunity of age-matched male and female healthy donors. We analyzed the effects of calcitriol in T lymphocytes from healthy women and men on the expression levels of the vitamin D receptor (VDR) and pro- and anti-inflammatory cytokine production. We showed that a treatment with calcitriol induced a significant increase in the VDR expression levels of activated T lymphocytes from male and female healthy subjects. Moreover, we found that calcitriol significantly reduced the expression level of pro-inflammatory cytokines IL-17, INF-γ and TNF-α in the T lymphocytes of both sexes. Notably, we observed that calcitriol induced a significant increase in the expression level of anti-inflammatory cytokine IL-10 only in the T lymphocytes from female healthy donors. In conclusion, our study provides new insights regarding the sex-specific anti-inflammatory role of calcitriol in T cell immunity.

Small Differences in Vitamin D Levels between Male Cardiac Patients in Different Stages of Coronary Artery Disease

Cardiovascular diseases are the main cause of mortality in males older than 65 years of age. The prevalent vitamin D deficiency in the worldwide population may have multiple effects on the cardiovascular system. This study sought to determine the association between serum levels of 25-hydroxyvitamin D (25(OH)D) and the stage of coronary artery disease (CAD) in Polish male subjects. Additionally, subjects with a history of myocardial infarction (MI) were analyzed for potential differences in 25(OH)D levels in comparison with those diagnosed with stable CAD. The study was conducted prospectively in a group of 669 male patients subjected to coronarography examination. CAD stage was defined using the Coronary Artery Surgery Study Score. Patients without significant coronary lesions had significantly higher 25(OH)D levels than patients with single-, double-, or triple-vessel disease (median, 17 vs. 15 ng/mL; p < 0.01). Significantly lower levels of 25(OH)D were apparent when MI was identified as the cause of the then-current hospitalization in comparison with stable CAD, as well as in patients with a history of MI; all of these cases had lower levels of 25(OH)D in comparison with patients with no such history. Male patients with single-, double-, or triple-vessel CAD, acute coronary syndrome, or a history of MI presented lower serum 25(OH)D.

Sleep duration as an independent factor associated with vitamin D levels in the EPISONO cohort

STUDY OBJECTIVES

Obstructive sleep apnea and short sleep duration have been separately associated with inadequate serum 25-hydroxyvitamin D [25(OH)D] levels. However, whether these 2 factors may concurrently influence 25(OH)D in the general population is unknown. We hypothesized that both obstructive sleep apnea and short sleep duration would be independently associated with lower concentrations of 25(OH)D in a sex-dependent manner.

METHODS

In this cross-sectional study, 712 individuals, part of the prospective EPISONO cohort (Brazil), underwent polysomnography, answered sleep questionnaires, and had their blood collected for serum 25(OH)D quantification.

RESULTS

Individuals with a sleep duration of < 6 hours had 2-fold increased odds of 25(OH)D < 20 ng/mL compared with those who reported 6 or more hours of sleep, even after adjusting for confounding factors. Subset sex analysis revealed that men with a sleep duration of < 6 hours had 4-fold increased odds of 25(OH)D < 20 ng/mL. In women, short sleep duration was not associated with lower 25(OH)D levels. The presence of obstructive sleep apnea (as classified according to the individual's apnea-hypopnea index) was not independently related to 25(OH)D concentrations in men or women. Sleep parameters, including sleep latency and sleep efficiency, had no association with 25(OH)D < 20 ng/mL.

CONCLUSIONS

Short sleep, but not apnea-hypopnea index, was an independent factor associated with low 25(OH)D serum levels in men, but not in women. Apnea-hypopnea index scores were not associated with 25(OH)D levels in either sex. These results raise the possibility of investigating sex-specific characteristics, such as gonadal hormone regulation, and re-evaluating obstructive events by classifying them in mild, moderate, and severe obstructive sleep apnea.

CITATION

de Oliveira DL, Dokkedal-Silva V, Fernandes GL, Kim LJ, Tufik S, Andersen ML. Sleep duration as an independent factor associated with vitamin D levels in the EPISONO cohort. J Clin Sleep Med. 2021;17(12):2439-2449.

A high prevalence of prediabetes and vitamin D deficiency are more closely associated in women: results of a cross-sectional study

OBJECTIVE

Many studies have shown that vitamin D deficiency is associated with insulin resistance and metabolic syndrome. However, few studies have shown independent associations between vitamin D deficiency and the metabolic characteristics of prediabetes. We aimed to evaluate the relationship between serum vitamin D concentration and metabolic risk factors in adults with prediabetes.

METHODS

We enrolled 161 patients aged 25 to 75 years in a cross-sectional study and collected clinical and biochemical data, including 25-hydroxyvitamin D (25[OH]D) status and fasting glucose concentration. Vitamin D status was defined as follows: deficiency (25[OH]D <49.9 ng/mL), insufficiency (49.9 to 74.9 nmol/L) or sufficiency (>74.9 nmol/L). Prediabetes was defined using fasting plasma glucose concentrations of 5.55 to 6.49 mmol/L.

RESULTS

The prevalences of vitamin D deficiency and insufficiency were 49.7% and 24.8%, respectively. Participants with vitamin D deficiency had a higher prevalence of prediabetes than those without (53.8% vs. 32.1%), and there was a significant relationship between female sex and vitamin D status (odds ratio: 1.382; 95% confidence interval: 0.335-5.693).

CONCLUSION

Vitamin D deficiency is more closely associated with a high prevalence of prediabetes in women than in men. Further studies are needed to elucidate the explanation for this association.

Sex disparity in skin carcinogenesis and potential influence of sex hormones

Background

Sex or gender disparity in skin cancer has been documented for a long time at the population level. UV radiation (UVR) is a common environmental risk for all three major types of skin cancer: cutaneous melanoma (CM), basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC). The underlying mechanism for sex disparity has been largely attributed to sex‐differentiated behaviour patterns related to UVR. Non‐UVR factors such as intrinsic physiological differences have been suggested but remain understudied.

Aims, Materials and Methods

This review summarizes and compares the known sex differences in three skin cancer types with regard to body site distribution and age influence.

Results

We found a similar age‐dependent sex difference pattern in CM and BCC. Specifically, CM and BCC tend to show higher incidence in young women and old men, with a switching age around menopause. The switching age suggests involvement of sex hormones, which has shown controversial influence on skin cancers at epidemiological level. Literatures regarding sex hormone receptors for oestrogen, androgen and progesterone are summarized for potential explanations at molecular level.

Discussion

Overall, more and more evidence suggests non‐UVR factors such as sex hormones play critical roles in skin cancer (especially CM and BCC), yet solid population and molecular evidence are required. Incidences of skin cancer are increasing which suggests limited effect for the current UVR‐avoidance prevention methods.

Conclusion

Fully understanding the causes of sex disparities in incidence is necessary for developing a comprehensive prevention strategy.

Vitamin D deficiency in primary health care users at risk in Spain

BACKGROUND AND OBJECTIVES

despite long hours of sunlight in Spain, vitamin D deficiency has been rising of late. We aimed to describe vitamin D deficiency and insufficiency in at-risk patients in La Rioja, a region in northern Spain.

METHODS

a retrospective, cross-sectional study involving 21,490 patients (74.3 % women) aged 14-105 years, who were primary health care (PHC) users in La Rioja, with an available 25-hidroxyvitamin D (25(OH)D) test result corresponding to the first request from January 2013 to October 2015. Vitamin D deficiency, insufficiency, and sufficiency were defined as 25(OH)D levels < 12 ng/mL, 12-20 ng/mL, and ≥ 20 ng/mL, respectively. Hypovitaminosis D was defined considering 2 cut-off points for 25(OH)D: < 20 ng/mL and < 30 ng/mL.

RESULTS

mean 25(OH)D levels were 18.3 (SD, 11.6) ng/mL in the whole sample, being lower in men than in women (17.6 vs 18.5 ng/mL, p < 0.001). Significantly higher 25(OH)D levels were found in the groups with 55-59, 60-64, 65-69, and 70-74 years of age (range, 19.4-20.4 ng/mL), and lower levels were found in the groups with 80-85 years and older (16.7 and 14.5 ng/mL), as compared to other groups. Two thirds of the population were vitamin D-deficient (< 12 ng/mL, 30.9 %) or insufficient (12-20 ng/mL, 32.8 %), and only 32.8 % of patients were found to be vitamin D-sufficient (> 20 ng/ml). Hypovitaminosis D rate was higher (89.7 %) when the 25(OH)D cut-off point was set at < 30 ng/mL. A higher hypovitaminosis D rate (< 20 ng/mL) was found in men (67.1 %) vs women (62.6 %) (p < 0.001), and it was more prevalent in patients over 75 years (72.6 %). The prevalence of hypovitaminosis D followed a seasonal pattern ranging from 51.8 % to 76.5 %; the lowest 25(OH)D levels were found in winter, and the highest in summer, with levels above 20 ng/mL in all age groups except for patients over 75 years (17.7 ng/mL). Patients over 75 years exhibited high rates of deficiency or insufficiency across all seasons of the year.

CONCLUSIONS

in La Rioja, Spain, hypovitaminosis D was highly prevalent among PHC users, and especially in older age groups and during the winter months.

Birth month and mortality in Japan: a population-based prospective cohort study

Epidemiologic studies investigating the association between birth season and risk of mortality in adulthood are limited and have yielded inconclusive results. We aimed to examine the relationship between birth month and all-cause and cause-specific mortality, after controlling for potential confounders, including lifestyle and medical factors, in a population-based cohort study in Japan. We included 28,884 subjects (13,262 men and 15,622 women) from Takayama City, aged 35 years or older without cancer, stroke, and ischemic heart disease, who were born in Japan at baseline. Participants who were enrolled in 1992 were followed up for over 16 years. Information including place of birth, lifestyles, and medical history was obtained from a baseline questionnaire. We performed a Cox proportional hazards analysis to determine the association between birth month and all-cause and cause-specific mortality after adjusting for potential confounders. During the follow-up period (mean follow-up: 14.1 years), 5,303 deaths (2,881 men and 2,422 women) were identified. After controlling for multiple covariates, it was found that being born in April or June was associated with an increased risk of all-cause mortality compared to being born in January (hazard ratio [HR] 1.138; 95% confidence interval [CI], 1.006-1.288 and HR 1.169; 95% CI, 1.028-1.329, respectively). The HRs for cardiovascular mortality were significantly higher in participants born in March and May (HR 1.285; 95% CI, 1.056-1.565 and HR 1.293; 95% CI, 1.040-1.608, respectively). Our findings indicate that an individual's birth month may be an indicator of the susceptibility to mortality in later life.

Relationship of Vitamin D status with testosterone levels: a systematic review and meta-analysis

PURPOSE

Despite a biological plausibility of a direct link between low vitamin D and androgen deficiency, the association remains inconclusive in epidemiological studies. Therefore, this systematic review and meta-analysis of case-control studies aim to assess whether and in what populations such an association can be demonstrated.

METHODS

A systematic search was performed in PubMed, EMBASE, Cochrane Library, Web of science, Science Direct, and CINAHL. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) in total testosterone (TT) levels between men with 25-hydroxyvitamin D (25(OH)D) <20 and ≥20 ng/mL were combined using random-effects models. Funnel plot and trim-and-fill analysis were used to assess publication bias. Heterogeneity source was explored by a sub-group analysis according to health-related characteristics of the study populations.

RESULTS

Eighteen included studies collectively gave information on 9892 men with vitamin D deficiency and 10,675 controls. The pooled SMD revealed a slight, albeit just significant, positive association between 25(OH)D and TT (pooled SMD: -0.23, 95% CI: -0.45 to -0.01; P = 0.04) with a large between-study heterogeneity (I² = 98%, P_{for heterogeneity} < 0.00001). At the sub-group analysis, a significant positive association, along with noticeable decrease in heterogeneity, could only be demonstrated in studies of patients with frailty states (pooled SMD: -0.19; 95% CI: -0.27, -0.10,  P < 0.0001; I² = 51%, P_{for heterogeneity} = 0.06). A sensitivity analysis revealed a high stability of the result and the trim-and-fill adjustment for publication bias did not affect pooled estimate.

CONCLUSIONS

Both hypovitaminosis D and androgen deficiency should be regarded as markers of a poor health status, sharing common underlying aetiologies and risk factors.

Effects of supraphysiological vitamin D3 (cholecalciferol) supplement on normal adult rat ovarian functions

This study measured the sequelae of cholecalciferol (VD₃) therapy on ovarian functions in adult VD-replete rats (n = 48). The animals were distributed into the control and VD groups following estrous cycle synchronisation. The VD group received VD₃ injections for 4 weeks (600 IU/Kg; 3 times/week). Vaginal cytology and cycle durations were recorded throughout the study. Serum VD (25-OH VD), Ca²⁺, gonadotrophins (FSH & LH) and sex steroids (E2 & progesterone) were measured following euthanasia. Follicles and corpora lutea were counted in ovarian tissue sections. VD receptor, binding protein, Ca²⁺-sensing receptor and retinoid X receptor-α genes and proteins were measured by quantitative RT-PCR and immunohistochemistry. Serum VD, LH, E2 and progesterone levels were significantly higher, whereas FSH declined, in the VD group than controls. VD₃ therapy was also associated with markedly higher rates alongside shorter durations of estrous cycles than controls. While serum Ca²⁺ levels were equal between the study groups, they correlated directly with serum 25-OH VD. The numbers of small and medium size ovarian follicles were equal in both study groups, whereas large follicles and corpora lutea counts were significantly higher in the VD group. The mRNAs and proteins of targeted molecules also increased substantially in the VD group than controls. In conclusion, treating VD-sufficient female rats with supraphysiological VD₃ supplements was not associated with hypercalcaemia, and could contribute to ovarian functions by regulating the hypothalamic-pituitary-ovarian hormones and ovarian VD-related molecules. However, further studies are still needed to illustrate the clinical significance of VD₃ in female reproduction.

The role of vitamin D in autoimmune diseases: could sex make the difference?

Over the last decades, a central role for vitamin D in immune modulation has been well established. The active form of vitamin D, i.e., 1,25-dihydroxyvitamin D, through the interaction with vitamin D receptor, exerts different activities on the innate and adaptive immune system, among which suppression of inflammation and promotion of tolerogenic responses. Vitamin D insufficiency has been linked to autoimmune disorders that commonly display significant differences between females and males due to genetic, epigenetic, hormonal, and environmental factors. Notably, a number of studies recently showed a cross-talk between vitamin D and the sex hormone estrogen. Estrogen-mediated effects on immune response may favor a Th1 profile or a Th2 profile, depending on hormone concentration. Thus, estrogen-mediated effects appear to be variable on autoimmunity depending on its concentration but also on the pathogenic mechanisms underlying the different autoimmune diseases (i.e., Th1- or Th2-mediated diseases). Notably, estrogen has been demonstrated to enhance vitamin D function favoring its accumulation, and increasing the expression of vitamin D receptor, thus resulting in a more potent anti-inflammatory response in females than males. On the other hand, vitamin D has been shown to downregulate in immune cells the expression of aromatase, which converts testosterone to estrogen, leading to a decrease in estrogen level. Overall, available data allow us to hypothesize a higher protective effect of vitamin D-based therapeutic approaches in women, at least in fertile age, than in men. Future studies are needed to expand current knowledge on the immunomodulatory role of vitamin D in a sex and gender perspective, paving the way to a more personalized therapeutic approach in autoimmune diseases.

Vitamin D status and prevalence of hypovitaminosis D in different genders throughout life stages: A Brazilian cross-sectional study

OBJECTIVES

To evaluate the mean concentration of 25-hydroxivitamin D [25(OH) D] and prevalence of hypovitaminosis D in individuals residing in Rio de Janeiro, Brazil.

METHODS

The data of 80,000 consecutive individuals who had 25(OH) D measurements performed by electrochemiluminescence between 1/2/2018 and 2/5/2018 were selected. Patients who reported the use of therapies/supplements were excluded. Levels of 25(OH) D ≥20 ng/mL (ages <60 years) and ≥30 ng/mL (ages ≥60 years) were considered adequate.

RESULTS

We analyzed the data of 24,074 individuals (1-95 years old, 64.7% female). Descriptive curves showed that, in both sexes, the mean values of 25(OH) D decreased from the first years of life until adolescence, then slightly increased, and then tended to stabilize during adulthood. Levels of 25(OH) D <20 ng/mL were observed in 6% of girls versus 3.6% of boys and in 13.6% of adolescent girls versus 12.6% of adolescent boys and 11% of adults. The percentage of seniors with serum levels of 25(OH) D <20 ng/mL was 13.6% in women and 12.7% in men; 53.2% of women and 50.6% of men had levels <30 ng/mL.

CONCLUSIONS

Mean 25(OH) D values were higher in children and lower in adolescents and women. Approximately 90% of non-seniors and presumably healthy residents of the urban metropolitan region of Rio de Janeiro presented satisfactory levels of 25(OH) D during the summer months; however, in over half of the elderly, the serum concentrations of 25(OH) D were inadequate. Therefore, strategies for the prevention of hypovitaminosis D should be considered in the senior population.

Association of Bone Mineral Density, Vitamin D, and Serum Calcium in Intracranial Aneurysm

Aims

The objective of this study is to understand the association between bone mineral density (BMD), serum calcium, and Vitamin D in s (IA) patients.

Subjects and Methods

A total of 100 patients with IA diagnosed at the department of neurosurgery between January 2019 and December 2019 were reviewed and analyzed in this study. Computed tomography angiography was used to confirm and locate the site of aneurysms. BMD, serum calcium, and Vitamin D levels were measured.

Statistical Analysis Used

Linear or logistic regression statistical models were applied to found the association between BMD and IA size. To confirm the statistical significance, P < 0.05 (twos-tailed) was considered as statistically significant.

Results

Of the studied 100 patients, 61 patients were female and 39 were male. According to the age group, patients were divided into five categories: below 30, 31-40, 41-50, 51-60, and ≥60 years. The most common site of aneurysm observed to be the anterior communicating artery (Acom); 39.25% of the patients had Acom aneurysm followed by the middle cerebral artery (18.69%). This clearly shows that the occurrence of aneurysm is more prominent in anterior circulation as compared to posterior circulation. The results showed that there is a negative linear correlation between BMD and size of aneurysm (P = 0.00043, r =-0.12). Sex-specific analysis showed that females have lower mean BMD value as compared to males (i.e., females 0.785 ± 0.13; males 0.887 ± 0.13; P = 0.0003). We also found that the multiplicity of IAs also shows an association with BMD (i.e. mean BMD: 0.825 ± 0.14, whereas BMD of patients with multiple aneurysms was 0.747 ± 0.08; P = 0.05). Of 100 patients, 66 were observed calcium deficient (normal range: 8.8-10.2 mg/dl). The obtained mean value of calcium was 8.56 ± 0.859 standard deviation (SD), i.e., below the normal range of calcium. In the case of Vitamin D, 85% of the patients were observed Vitamin D deficient, whereas 14 patients showed Vitamin D insufficiency and merely 1 patient has Vitamin D sufficiency. The mean 25-hydroxy Vitamin D level obtained in our study was 14.57 ± 5.60 (SD), which is considered as Vitamin D deficiency.

Conclusions

The size and multiplicity of IA can be associated with BMD, calcium, and Vitamin D. The results from the research provide evidence of common pathophysiology between the development of IA and these factors.

Vitamin D Deficiency Induces Elevated Oxidative and Biomechanical Damage in Coronary Arterioles in Male Rats

Background: Several reports prove interconnection between vitamin D (VD) deficiency and increased cardiovascular risk. Our aim was to investigate the effects of VD status on biomechanical and oxidative–nitrative (O–N) stress parameters of coronary arterioles in rats. Methods: 4-week-old male Wistar rats were divided into a control group (11 animals) with optimal VD supply (300 IU/kgbw/day) and a VD-deficient group (11 animals, <5 IU/kg/day). After 8 weeks, coronary arteriole segments were prepared. Geometrical, elastic, and biomechanical characteristics were measured by in vitro arteriography. O–N stress markers were investigated by immunohistochemistry. Results: Inner radius decreased; wall thickness and wall-thickness/lumen diameter ratio increased; tangential wall stress and elastic modulus were reduced in VD-deficient group. No difference could be found in wall-cross-sectional area, intima-media area %. While the elastic elements of the vessel wall decreased, the α-smooth muscle actin (α-SMA) immunostaining intensity showed no changes. Significant elevation was found in the lipid peroxidation marker of 4-hidroxy-2-nonenal (HNE), while other O–N stress markers staining intensity (poly(ADP)ribose, 3-nitrotyrosine) did not change. Conclusions: Inward eutrophic remodeling has developed. The potential background of these impairments may involve the initial change in oxidative damage markers (HNE). These mechanisms can contribute to the increased incidence of the cardiovascular diseases in VD deficiency.

Association between blood cadmium and vitamin D levels in the Yangtze Plain of China in the context of rapid urbanization

BACKGROUND

China has experienced rapid urbanization in the past 30 years. We aimed to report blood cadmium level (BCL) in the rapidly urbanized Yangtze Plain of China, and explore the association between BCL and 25-hydroxyvitamin D (25(OH)D).

METHODS

Our data source was the Survey on Prevalence in East China for Metabolic Diseases and Risk Factors (SPECT-China) cross-sectional study (ChiCTR-ECS-14005052, www.chictr.org). We enrolled 3234 subjects from 12 villages in the Yangtze Plain. BCLs were measured by atomic absorption spectrometry. 25(OH)D was measured with a chemiluminescence assay.

RESULTS

A total of 2560 (79.2%) subjects were diagnosed with vitamin D deficiency. The median (interquartile range) BCL was 1.80 μg/L (0.60-3.42) for men and 1.40 μg/L (0.52-3.10) for women. In women, mean 25(OH)D concentrations were inversely associated with BCL (0.401, 95% confidence interval: -0.697 to -0.105 nmol/L lower with each doubling of the BCL) after adjustment for age, educational status, current smoking, body mass index, diabetes, and season. However, there was no significant difference in 25(OH)D across the BCL tertiles for men.

CONCLUSIONS

BCL in Chinese residents in the Yangtze Plain were much higher than that in developed countries. An inverse association between BCL and 25(OH)D was found in general Chinese women after multivariable adjustment. Future prospective cohort and animal studies are warranted to resolve the direction and temporality of these relationships, and to elucidate the exact mechanisms involved.

The synergistic effects of vitamin D and estradiol deficiency on metabolic syndrome in Chinese postmenopausal women

OBJECTIVE

Recent studies show that vitamin D (VitD) deficiency is associated with metabolic syndrome (MetS). Current evidence suggests that estrogen and VitD have similar physiological functions and potentially interact with bone health. We investigated the association between estradiol (E2) and 25-hydroxyvitamin-D [25(OH)D] with MetS and its components in Chinese postmenopausal women.

METHODS

In this cross-sectional study, we examined 616 postmenopausal women (aged 49-86 y) from southern China who were not taking estrogen and VitD/calcium supplements. At the end of data collection, serum E2 and 25(OH)D were measured for each participant. MetS was defined according to the 2006 International Diabetes Federation standard.

RESULTS

There was a positive correlation between 25(OH)D and E2. Higher 25(OH)D was associated with a favorable lipid profile, blood pressure, and glucose level. E2 was negatively associated with cholesterol, triglycerides, and blood pressure. The odds ratio for MetS was 2.19 (95% CI, 1.19-4.01, P value for trend=0.009) for deficient compared with sufficient women after multivariable adjustment. This association remained unchanged after further adjusting for E2 levels. After stratified analysis by VitD status, low E2 increased MetS risk in women with VitD deficiency (odds ratio = 3.49, 95% CI, 1.45-8.05 for the lowest vs the highest tertile).

CONCLUSIONS

These results suggest a synergistic role of VitD and E2 deficiency in MetS in Chinese postmenopausal women.

Serum 25-Hydroxyvitamin D Concentrations Are Associated with Mental Health and Psychosocial Stress in Young Adults

We aimed to test the hypothesis that serum 25-hydroxyvitamin D₃ (25(OH)D) concentration is associated with mental health and life stress measures in young adults and investigate gender and racial disparities in these associations. This study comprised 327 black and white participants. Depression, trait anxiety, perceived stress, and hostility were measured by the following validated instruments: Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), Perceived Stress Scale (PSS), and Cook–Medley Hostility Scale (CMHS). Linear regression was used to estimate correlations between serum 25(OH)D concentration and mental health measurements in the total population and in subgroups stratified by gender and race. In this sample (28.2 ± 3.1 years, 52% female, 53% black), serum 25(OH)D concentration was negatively related to BDI, STAI, PSS, total CMHS score, and the majority of CMHS subscale scores (p-values < 0.05). Stratified by gender, most of these associations remained significant only in women (p-values < 0.05). Stratified by race, higher 25(OH)D concentrations in white participants were significantly related to lower BDI, STAI, PSS, and CMHS-cynicism subscales (p-values < 0.05); 25(OH)D concentrations in the black participants were only inversely associated with CMHS and most CMHS subscales (p-values < 0.05) but not with BDI, STAI, and PSS. We present novel findings of consistent inverse relationships between serum 25(OH)D concentration and various measures of mental health and life stress. Long-term interventional studies are warranted in order to investigate the roles of vitamin D supplementation in the prevention and mitigation of depression, anxiety, and psychological stress in young adults.

Effects of Dietary or Supplementary Micronutrients on Sex Hormones and IGF-1 in Middle and Older Age: A Systematic Review and Meta-Analysis

Observational research suggests that micronutrients may be protective for sarcopenia, a key health issue during ageing, potentially via effects on hormone synthesis and metabolism. We aimed to carry out a systematic review of RCTs investigating effects of increasing dietary or supplemental micronutrient intake on sex hormones and IGF-1 in individuals aged 45 years or older. We searched MEDLINE, EMBASE and Cochrane databases for RCTs reporting the effects of different micronutrients (vitamins A, C, D, or E; carotenoids; iron; copper; zinc; magnesium; selenium; and potassium) on sex hormones or IGF-1. Of the 26 RCTs identified, nine examined effects of vitamin D, nine of multi-nutrients, four of carotenoids, two of selenium, one of zinc, and one of vitamin E. For IGF-1 increasing vitamin D (MD: -0.53 nmol/L, 95% CI: -1.58, 0.52), multi-nutrients (MD: 0.60 nmol/L, 95% CI -1.12 to 2.33) and carotenoids (MD -1.32 nmol/L; 95% CI -2.76 to 0.11) had no significant effect on circulating concentrations. No significant effects on sex hormones of other micronutrients were found, but data were very limited. All trials had significant methodological limitations making effects of micronutrient supplementation on sex hormones unclear. Further high quality RCTs with physiological doses of micronutrients in people with low baseline intakes or circulating concentrations, using robust methodology, are required to assess effects of supplementation adequately.

Gender differences in the prevalence of vitamin D deficiency in a southern Latin American country: a pilot study

Aim: This study aimed to study the prevalence of vitamin D deficiency, assessing the influence of sex, age, and season of the year.Methods: A cross-sectional study was conducted with 1329 healthy subjects (668 women and 661 men) aged 18-89 years in Santiago, Chile. Age (years), body mass index, medical history, working status, sex, and date of blood sample were collected.Results: Men were slightly older than women (53.1 ± 18.2 vs. 50.0 ± 15.6 years; p < 0.01) and a higher percentage worked outside the home (73.1% vs. 51.9%, p < 0.001). The mean serum concentration of 25-hydroxyvitamin D (25(OH)-D) was 23.3 ± 9.3 ng/ml in women and 20.9 ± 9.5 ng/ml in men (p < 0.001). The levels of 25(OH)-D by season were 26.7 ± 9.0, 23.6 ± 9.7, 19.4 ± 8.5, and 19.1 ± 9.5 ng/ml (for summer, fall, winter, and spring, respectively; p < 0.05). The prevalence of vitamin D deficiency increases with age, rising from 36.5% under 40 years to 48.0% over 60 years (p < 0.004). Male sex, winter and spring, and age showed negative correlation with levels of 25(OH)-D (p < 0.05). Multivariate linear regression showed a final model that incorporates: age (coefficient: -0.06; 95% confidence interval [CI]: -0.09 to -0.03; p < 0.001), male sex (coefficient: -2.00; 95% CI: -2.96 to -1.05; p < 0.001), summer (coefficient: 7.30; 95% CI: 6.17 to 8.43; p < 0.001), and fall (coefficient: 4.27; 95% CI: 3.04 to 5.50; p < 0.001).Conclusions: Vitamin D deficiency is more prevalent in men than in women, in the elderly, and during the winter and spring seasons.

Sex-Specific Association between Serum 25-Hydroxyvitamin D and Metabolic Risk Factors in T2DM Patients

OBJECTIVE

To evaluate the relationship between serum 25-hydroxyvitamin (25(OH)D) levels and metabolic risk factor levels in patients with type 2 diabetes mellitus (T2DM) on a sex-specific basis.

METHODS

Our study comprised 507 patients with T2DM (321 men, 186 women; median age, 59 years). The metabolic risk factors examined included lipoprotein(a), glycated albumin (GA-L), and random blood glucose (RBG); the levels of these parameters were determined enzymatically. Serum 25(OH)D levels were measured by commercial ELISA kits. Participants were divided into low and high 25(OH)D groups according to the median 25(OH)D concentration (13.2 ng/mL). Two-way analysis of covariance and multiple linear regression analysis were performed.

RESULTS

The median 25(OH)D concentration was 13.9 ng/mL in men and 12.2 ng/mL in women. 25(OH)D levels inversely correlated with levels of three metabolic risk factors in a sex-dependent manner after adjusting for several confounding factors. These were lipoprotein(a) in men (141.3 ± 137.9 and 195.3 ± 204.8 mg/L in high and low 25(OH)D groups, respectively; P < 0.05); GA-L in women (22.2 ± 8.8 vs. 23.3 ± 7.3% in high and low 25(OH)D groups, respectively; P < 0.05). In a subgroup analysis, serum 25(OH)D levels inversely correlated with lipoprotein(a) levels in men (β = -0.185, P = 0.002) and RBG levels in women (β = -0.176, P = 0.028).

CONCLUSION

Higher serum 25(OH)D levels indicate a more favorable lipid profile in men and a more favorable glucose profile in women.

Pre-conception 25-hydroxyvitamin D (25(OH)D) and fecundability

STUDY QUESTION

Is pre-conception 25(OH)D associated with the per cycle probability of conception, i.e fecundability, in a prospective cohort study?

SUMMARY ANSWER

There are suggestive associations of high 25(OH)D (at least 50 ng/ml) with increased fecundability and low 25(OH)D (<20 ng/ml) with reduced fecundability, but the estimates were imprecise.

WHAT IS KNOWN ALREADY

Vitamin D has been associated with reproductive function and fertility in animal studies, but few human studies exist.

STUDY DESIGN, SIZE, DURATION

This community-based prospective cohort study included 522 women attempting to become pregnant between 2010 and 2016. The women completed online daily and monthly diaries until a positive home pregnancy test was observed or 12 months had elapsed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included women from central North Carolina who were aged 30-44 with no history of infertility, with no more than 3 months of attempt time at recruitment. Women recorded vaginal bleeding so that the ongoing number of attempt cycles could be counted and used to quantify a woman's pregnancy attempt time. Blood collected at the study entry was analysed for 25(OH)D using liquid chromatography tandem mass spectrometry. Associations with fecundability were estimated with a log-binomial discrete time-to-event model.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 522 women, 257 conceived during the study. The mean age was 33 years and the mean 25(OH)D was 36 ng/ml. There was an estimated 10% higher fecundability with each 10 ng/ml increase in 25(OH)D (fecundability ratio (FR) 1.10, 95% CI: 0.96, 1.25). The suggestive dose-response association with the continuous measure of 25(OH)D was driven by women in the lowest and the highest categories of 25(OH)D. Compared to women with 25(OH)D of 30-40 ng/ml, women below 20 ng/ml had an estimated 45% reduction in fecundability (FR (CI): 0.55 (0.23, 1.32)), and women with at least 50 ng/ml had an estimated 35% increase in fecundability (FR (CI): 1.35 (0.95, 1.91)). Across these three categories (25(OH)D of <20 ng/ml, 30-40 ng/ml and > 50 ng/ml), the probability of taking longer than 6 months to conceive was, respectively, 51% (17%, 74%), 28% (17%, 39%) and 15% (10%, 37%).

LIMITATIONS, REASONS FOR CAUTION

While the distribution of 25(OH)D was wide, the number of observed cycles with high 25(OH)D (N = 107) or low 25(OH)D (N = 56) was small.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings are consistent with prior reports of reduced fertility in women with 25(OH)D concentrations below the clinically defined deficiency level (20 ng/ml). Further studies are needed to evaluate the possible reproductive benefits of considerably higher 25(OH)D concentration (>50 ng/ml).

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (NIH) under award numbers R00HD079659 and R01HD067683 and supported in part by the Intramural Research Program of the National Institute of Environmental Health Sciences, under projects ES103086, ES049003 and ES044003. ClearBlue ovulation predictor kits were generously donated to AMZJ and AJW by Swiss Precision Diagnostics. Drs Wilcox and Jukic report non-financial support from Swiss Precision Diagnostics during the conduct of the study; Dr Jukic reports non-financial support from Theralogix, LLC, outside the submitted work. Otherwise there are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Relationship among urinary advanced glycation-end products, skeletal muscle mass and physical performance in community-dwelling older adults

AIM

Advanced glycation end-products are important factors in muscle function and physical performance among older adults. However, the association between sarcopenia and urinary carboxymethyl-lysine (uCML) levels remains unclear. The present study aimed to investigate the relationship among uCML levels, skeletal muscle mass, physical performance and sarcopenia among community-dwelling older adults.

METHODS

This work was a community-based cross-sectional study. The participants were recruited from the Taichung Community Health Study-Elderly and were followed up until 2017. A total of 104 participants underwent dual-energy X-ray absorptiometry examination, physical performance tests and measurement of uCML levels. After the natural log transformation of the uCML levels, Pearson's correlation coefficient and a general linear model were used for statistical analysis.

RESULTS

The mean uCML levels of older men and women were 1.34 μg/mg and 1.63 μg/mg creatinine, respectively. After multivariate adjustment, grip strength among older women significantly decreased as uCML levels increased. Participants with uCML levels and Timed Up and Go test values higher than the median had a 13.76-fold risk of acquiring sarcopenia compared with those whose corresponding variables were lower than the median after adjusting for age, sex, body fat percentage, and serum creatinine and blood urea nitrogen levels.

CONCLUSIONS

uCML levels were negatively associated with grip strength among older women. The joint association of uCML and Timed Up and Go test values was correlated with the risk of acquiring sarcopenia among older adults. This finding suggests that uCML levels can be used as a biomarker for screening sarcopenia and as a strategy for treating sarcopenia. Geriatr Gerontol Int 2019; 19: 1017-1022.

Relationship between serum homocysteine and different menopausal stage

Objective: This study aimed to investigate the serum level of homocysteine in menopausal women and to explore the association between menopausal status, blood lipids, and homocysteine concentrations.Methods: The study recruited females aged 40-60 years who were not receiving menopausal hormone therapy. The demographic characteristics and menopausal status of the women were collected in the form of questionnaires. The study analyzed the association between hyperhomocysteinemia and variables using binary logistic stepwise regression.Results: Among 366 enrolled subjects, menopausal status was divided into four stages: premenopause stage (n = 135), menopausal transition stage (n = 91), early postmenopause stage (n = 87), and late postmenopause stage (n = 53). The proportion of hyperhomocysteinemia in the premenopausal stage, menopausal transition stage, and postmenopausal stage was 43%, 26.4%, and 45%, respectively (χ² = 8.999, p = 0.011). The mean concentration of homocysteine was 9.75 µmol/l. The level of homocysteine was higher in the postmenopause stage than in the other stages (p = 0.043), and the difference between postmenopause and menopausal transition was statistically significant (p < 0.01). In the binary logic analysis, menopausal transition compared with postmenopause (odds ratio = 2.027, 95% confidence interval = 1.117-3.679, p = 0.005).Conclusions: Serum homocysteine levels are associated with menopausal status. Homocysteine concentrations were progressively higher across menopausal stages. The transformation in the female body across the menopause transition stages may cause elevations in the homocysteine level in postmenopausal women.

Vitamin D and Male Fertility: An Updated Review

To date, the key role of vitamin D in male reproductive system has been suggested, since the expression of vitamin D receptors and metabolizing enzymes was demonstrated in the testis and spermatozoa. Nevertheless, a general consensus about the role of vitamin D in male fertility is still debated. The aim of this review is to provide an updated systematic revision of the current available literature, discussing the experimental and clinical evidence on the role of vitamin D in the regulation of testis hormone production, seminal parameters and male fertility. The consequences of vitamin D deficiency on serum levels of testicular hormones have been analysed by several observational and interventional studies, with controversial results. Equally, the experimental researches not were able to state a certain relationship between vitamin D status and testis hormone production. Possible bias, including age, body mass index, and baseline vitamin D status justified the differences among studies. As well as concerning the effect of vitamin D on semen parameters, most of the studies agreed in the possibility that vitamin D might have a positive effect on human male fertility potential, particularly through better sperm motility. Regarding pregnancy outcomes, normal level of vitamin D seems to be related to better pregnancies. However, all the previous studies displayed a wide heterogeneity in study design, population, methodology, and cut off values used for the evaluation of vitamin D status. Future studies are needed to better clarify the exact role of vitamin D on hormonal and seminal panel in both fertile and infertile men.

Assessing the effect of omega-3 fatty acid combined with vitamin D3 versus vitamin D3 alone on estradiol levels: a randomized, placebo-controlled trial in females with vitamin D deficiency

Purpose

Outcomes investigating the effect of vitamin D3 (VD3) and omega-3 fatty acids (Omega-3FA) on serum estradiol (E2) are scarce and conflicting. No previous study has investigated the effect of VD3 combination with Omega-3FA on E2 levels. This study was designed to investigate the effect of VD3, Omega-3FA and VD3 plus Omega-3FA on serum E2 levels in premenopausal females diagnosed with vitamin D deficiency (VDD).

Subjects and methods

This randomized, placebo-controlled clinical trial was designed to evaluate the effects of 50,000 IU VD3 taken weekly, 300 mg Omega-3FA taken daily and their combination by the study participants for 8 weeks. The mid-follicular serum levels of E2 and 25-hydroxy vitamin D (25OHD) were assessed at 8 weeks. The study was conducted during winter on a convenience sample of healthy premenopausal Jordanian females with diagnosed VDD. Fasting serum levels for 25OHD and E2 were assessed at baseline and the end of the trial (after 8 weeks). Data were entered into SPSS and analyzed.

Results

Healthy premenopausal Jordanian females (N=86) with diagnosed VDD, mean age 32.8±8.9 years, were recruited into the study. Supplementation of VD3 alone resulted in a significant increase in serum 25OHD (13.4±7.9–28.2±7.1 ng/mL, P<0.001) and a significant decrease in E2 levels (85.7±16.5–60.3±20.6 pg/mL, P=0.001). Omega-3FA intake led to a significant decrease in serum 25OHD levels (21.2±12.8–13.6±9.2 ng/mL, P=0.001) and a significant increase in E2 levels (56.3±19.2–78.4±23.7 pg/mL, P=0.006). Combination therapy (VD3 plus Omega-3FA) resulted in a significant increase in both 25OHD (12.0±4.7–35.1±9.5 ng/mL, P<0.001) and E2 (43.0±23.4–57.3±31.5 pg/mL, P=0.028) levels.

Conclusion

Results of this study provide vital insight into the effects of D3, Omega-3FA and a combination of their supplementation on premenopausal Jordanian females with diagnosed VDD. Eight weeks of therapy led to decreased E2 level by VD3 and increased level by Omega-3FA supplementation. With regard to 25OHD, its level was increased by VD3 and decreased by Omega-3FA supplementation. Combination of VD3 plus Omega-3FA increased the levels of both E2 and 25OHD.

Trial registration

This trial was registered at clinicaltrials.gov as NCT03333564.

Vitamin D is associated with bioavailability of androgens in eumenorrheic women with prior pregnancy loss

BACKGROUND

Prior studies have reported mixed results regarding relationships between vitamin D, androgens, and sex hormone-binding globulin in patients with polycystic ovary syndrome. However, less is known regarding these associations in eumenorrheic, premenopausal women.

OBJECTIVE

Our objective was to study the relationships between serum vitamin D and androgen biomarkers in eumenorrheic women with a history of pregnancy loss who were attempting pregnancy.

STUDY DESIGN

This was an analysis of a cohort of 1191 participants from the Effects of Aspirin in Gestation and Reproduction trial (2006-2012). Participants were attempting to conceive, aged 18-40 years, with 1-2 documented prior pregnancy losses and no history of infertility, and recruited from 4 academic medical centers in the United States. Serum vitamin D (25-hydroxyvitamin D) and hormone concentrations were measured at baseline.

RESULTS

Vitamin D concentration was negatively associated with free androgen index (percentage change [95% confidence interval, -5% (-8% to -2%)] per 10 ng/mL increase) and positively associated with sex hormone-binding globulin (95% confidence interval, 4% [2-7%]), although not with total testosterone, free testosterone, or dehydroepiandrosterone sulfate after adjusting for age, body mass index, smoking status, race, income, education, physical activity, and season of blood draw.

CONCLUSION

Overall, vitamin D was associated with sex hormone-binding globulin and free androgen index in eumenorrheic women with prior pregnancy loss, suggesting that vitamin D may play a role in the bioavailability of androgens in eumenorrheic women. We are limited in making assessments regarding directionality, given the cross-sectional nature of our study.

Vitamin D, PCOS and androgens in men: a systematic review

BACKGROUND

Accumulating evidence from animal and human studies suggests that vitamin D is involved in many functions of the reproductive system in both genders.

AIM

The aim of this review was to provide an overview on the effects of vitamin D on polycystic ovary syndrome (PCOS) in women and androgen metabolism in men.

METHODS

We performed a systematic literature search in PubMed for relevant English language publications published from January 2012 until September 2017.

RESULTS AND DISCUSSION

The vitamin D receptor and vitamin D-metabolizing enzymes are found in reproductive tissues of women and men. In women, vitamin D status has been associated with several features of PCOS. In detail, cross-sectional data suggest a regulatory role of vitamin D in PCOS-related aspects such as ovulatory dysfunction, insulin resistance as well as hyperandrogenism. Moreover, results from randomized controlled trials (RCTs) suggest that vitamin D supplementation may be beneficial for metabolic, endocrine and fertility aspects in PCOS. In men, vitamin D status has been associated with androgen levels and hypogonadism. Further, there is some evidence for a favorable effect of vitamin D supplementation on testosterone concentrations, although others failed to show a significant effect on testosterone levels.

CONCLUSION

In summary, vitamin D deficiency is associated with adverse fertility outcomes including PCOS and hypogonadism, but the evidence is insufficient to establish causality. High-quality RCTs are needed to further evaluate the effects of vitamin D supplementation in PCOS women as well as on androgen levels in men.

Optimal Vitamin D Status in a Middle-Aged and Elderly Population Residing in Shanghai, China

BACKGROUND The aim of this study was to investigate the optimal vitamin D status in the middle-aged and elderly population residing in Shanghai, China. MATERIAL AND METHODS A total of 1,829 males and postmenopausal females older than 45 years of age in the Changfeng community of Shanghai were included in this study. The optimal vitamin D level was determined according to the suppression of parathyroid hormone (PTH) and the highest bone mineral density (BMD). Locally weighted scatter plot smoothing (LOWESS) was performed to study the correlations of 25(OH)D with PTH and BMD in the lumbar spine and total hip, adjusting for gender, age, weight, use of calcium and vitamin D supplements, eGFR, smoking status, and alcohol consumption. RESULTS The mean serum 25(OH)D concentration was 48.0±19.2 nmol/L for the whole study population. The circulating PTH was maximally suppressed by the serum 25(OH)D of 55 nmol/L in the total population (60 nmol/L for males and 50 nmol/L for females). The 25(OH)D concentrations corresponding to the highest BMD at lumbar spine (L1-L4) and total hip were 53 nmol/L and 75 nmol/L, respectively, for the whole population. These values were also higher in males than females. CONCLUSIONS The optimal 25(OH)D concentration of 55 nmol/L is sufficient to maintain the bone health and metabolic status in middle-aged and elderly individuals living in Shanghai. Males probably need higher vitamin D concentration than females. There are differences between vitamin D status based on lumbar spine BMD and total hip BMD.

Vitamin D Supplementation Changed Relationships, Not Levels of Metabolic-Hormonal Parameters in Autoimmune Thyroiditis

In women with chronic autoimmune thyroiditis and vitamin D deficiency we have found reference levels of relevant metabolic-hormonal parameters except for parathormone and total calcium. Three months supplementation with vitamin D (4300 IU/day, cholekalciferol) did not lead to significant changes of investigated hormonal parameters, while the levels of parathormone and calcium reached normal levels. However, a correlation analysis revealed marked changes in mutual relations. First, an inverse correlation of vitamin D with parathormone, insulin secretion (C peptide, insulin) and its efficiency (HOMA IR) disappeared. Relationships of vitamin D to hepatic insulin resistance (insulin/C peptide), to DHEA (both negative), and to DHEAS/DHEA ratio (positive) were newly found. Second, a positive correlation of CRP with insulin secretion remained, while its relation to insulin efficiency (HOMA IR, insulin/ C peptide) was newly observed. Analogical positive correlations appeared also among anti TPO and insulinemia, insulin/C peptide, HOMA IR, and anti Tg to C peptide. A relationship of the CRP with anti TPO became significant (+). Third, out of glucose metabolism parameters only insulin/C peptide and glycemia did not correlate with vitamin D during its deficiency, while after supplementation insulin/ C peptide alone correlated positively with both DHEAS and DHEA, and negatively with vitamin D.

The role of vitamin D in male fertility: A focus on the testis

In the last decade, vitamin D has emerged as a pleiotropic molecule with a multitude of autocrine, paracrine and endocrine functions, mediated by classical genomic as well as non-classical non-genomic actions, on multiple target organs and systems. The expression of vitamin D receptor and vitamin D metabolizing enzymes in male reproductive system, particularly in the testis, suggests the occurrence of vitamin D synthesis and regulation as well as function in the testis. The role of vitamin D in the modulation of testis functions, including hormone production and spermatogenesis, has been investigated in animals and humans. Experimental studies support a beneficial effect of vitamin D on male fertility, by modulating hormone production through genomic and non-genomic actions, and, particularly, by improving semen quality essentially through non-genomic actions. However, clinical studies in humans are controversial. Indeed, vitamin D seems to contribute to the modulation of the bioavailable rather than total testosterone. Moreover, although an increased prevalence or risk for testosterone deficiency was reported in men with vitamin D deficiency in observational studies, the majority of interventional studies demonstrated the lack of effect of vitamin D supplementation on circulating levels of testosterone. The most consistent effect of vitamin D was reported on semen quality. Indeed, vitamin D was shown to be positively associated to sperm motility, and to exert direct actions on spermatozoa, including non-genomic driven modulation of intracellular calcium homeostasis and activation of molecular pathways involved in sperm motility, capacitation and acrosome reaction. The current review provides a summary of current knowledge on the role of vitamin D in male fertility, by reporting clinical and experimental studies in humans and animals addressing the relationship between vitamin D and testis function.

Vitamin D and multiple sclerosis: An update

The most recent findings linking exposure to sun and vitamin D insufficiency to multiple sclerosis (MS) are reviewed. Due to insufficient sunshine and changing lifestyles, hypovitaminosis D is widespread in temperate countries. Numerous epidemiological studies have strongly suggested that sunshine and vitamin D insufficiency contributes to MS risk in these countries. Moreover, several large genetic studies in MS patients have recently stated unequivocally that diverse abnormalities involving vitamin D metabolism are related to the risk of the disease. The important implications of such results are discussed here. Then, the interactions of hypovitaminosis D with the other genetic and environmental protective and risk factors, such as the allele HLA DRB1*1501, Epstein-Barr virus infection, obesity, smoking and sexual hormones, are summarized. Vitamin D insufficiency and sufficiency could be a risk and a protective factor, respectively, among many other factors possibly continuously modulating the global MS risk from the mother's pregnancy to the triggering of MS in adulthood. However, many interactions between these different factors occur more particularly between conception and the end of adolescence, which corresponds to the period of maturation of the immune system and thymus and may be related to the dysimmune nature of the disease. The main mechanisms of action of vitamin D in MS appear to be immunomodulatory, involving the various categories of T and B lymphocytes in the general immune system, but neuroprotector and neurotrophic mechanisms could also be exerted at the central nervous system level. Furthermore, several controlled immunological studies performed in MS patients have recently confirmed that vitamin D supplementation has multiple beneficial immunomodulatory effects. However, there is still an enduring absence of major conclusive randomized clinical trials testing vitamin D supplementation in MS patients because of the quasi-insurmountable practical difficulties that exist nowadays in conducting and completing over several years such studies involving the use of a vitamin. Nevertheless, it should be noted that similar robust statistical models used in five different association studies have already predicted a favorable vitamin D effect reducing relapses by 50-70%. If there is now little doubt that vitamin D exerts a beneficial action on the inflammatory component of MS, the results are as yet much less clear for the progressive degenerative component. Lastly, until more information becomes available, vitamin D supplementation of MS patients, using a moderate physiological dose essentially correcting their vitamin insufficiency, is recommended.

Serum vitamin D and change in lipid levels over 5 y: The Atherosclerosis Risk in Communities study

OBJECTIVES

Deficiency of 25-hydroxyvitamin D (25[OH]D) is associated with increased risk for cardiovascular disease, perhaps mediated through dyslipidemia. Deficient 25(OH)D is cross-sectionally associated with dyslipidemia, but little is known about longitudinal lipid changes. The aim of this study was to determine the relationship of 25(OH)D deficiency to longitudinal lipid changes and risk for incident dyslipidemia.

METHODS

This was a longitudinal community-based study of 13 039 participants from the ARIC (Atherosclerosis Risk in Communities) study who had 25(OH)D and lipids measured at baseline (1990-1992) and lipids remeasured in 1993 to 1994 and 1996 to 1998. Mixed-effect models were used to assess the association of 25(OH)D and lipid trends after adjusting for clinical characteristics and for baseline or incident use of lipid-lowering therapy. Risk for incident dyslipidemia was determined for those without baseline dyslipidemia.

RESULTS

Baseline mean ± SD age was 57 ± 6 y and 25(OH)D was 24 ± 9 ng/mL. Participants were 57% women, 24% black. Over a mean follow-up of 5.2 y, the fully adjusted average differences (95% confidence interval [CI]) comparing deficient (<20 ng/mL) to optimal (≥30 ng/mL) 25(OH)D were: total cholesterol (TC) -2.40 mg/dL (-4.21 to -0.60), high-density lipoprotein cholesterol (HDL-C) -3.02 mg/dL (-3.73 to -2.32) and the ratio of TC to HDL-C 0.18 (0.11-0.26). Those with deficient compared with optimal 25(OH)D had modestly increased risk for incident dyslipidemia in demographic-adjusted models (relative risk [RR], 1.19; 95% CI, 1.02-1.39), which was attenuated in fully adjusted models (RR, 1.12; 95% CI, 0.95-1.32).

CONCLUSIONS

Deficient 25(OH)D was prospectively associated with lower TC and HDL-C and a greater ratio of TC to HDL-C after considering factors such as diabetes and adiposity. Further work including randomized controlled trials is needed to better assess how 25(OH)D may affect lipids and cardiovascular risk.