The Relationship between Vitamin D Status and the Menstrual Cycle in Young Women: A Preliminary Study

The Key Role of Vitamin D in Female Reproductive Health: A Narrative Review

Vitamin D, besides its crucial role in bone health and immune function, has received increased attention in recent years due to its possible impact on many processes related to female reproductive health. Recent research has tried to explain the role played by vitamin D in maintaining adequate hormonal status, fertility, and pregnancy outcomes. Our aim for this narrative literature review was to highlight and explain the mechanisms through which vitamin D status impacts female reproductive health. We believe this represents a very important subject of research, especially due to the increased incidence of infertility nowadays. Further studies are necessary on the association between vitamin D status and female reproductive health in order to fully understand its effects and to reach a consensus regarding vitamin D supplementation as a method to improve fertility status.

The effect of iron supplementation on menstrual bleeding volume and hemoglobin level during menstrual bleeding : A randomized clinical trial

BACKGROUND

Many women around the world avoid taking iron supplements during their menstrual bleeding, thinking that menstrual bleeding will increase after taking these supplements. Due to the lack of relevant scientific evidence in this regard, this study was performed to determine the effect of iron supplementation on menstrual blood volume and hemoglobin level during menstrual bleeding.

MATERIALS AND METHODS

In this three-blind randomized clinical trial, 160 non-anemic female students of Rafsanjan University of Medical Sciences were selected through a public call and then they were randomly assigned to two intervention and control groups. The intervention group was given a ferrous sulfate tablet containsing 50 mg of elemental iron daily in the first four days of bleeding for three consecutive menstrual cycles, and the control group received a placebo simultaneously. Before and after the intervention, the level of hemoglobin was measured and the Higham chart was completed in each menstrual cycle by the participants of the two groups. The obtained data were analyzed using the SPSS software version 21 and Chi-square, independent t-test, paired t-test, analysis of variance with repeated measures, and nonparametric tests.

RESULTS

Before performing the intervention, the mean Higham score and hemoglobin level of the two groups were not statistically significant (P = 0.307, P = 0.670). The mean Higham score after each intervention was not statistically significant between the two groups over time or when considering the interaction of the time group (P = 0.77, P = 0.916). The hemoglobin level of these two groups did not change significantly after the intervention compared with that before the intervention (P = 0.444).

CONCLUSION

Compared with a placebo, taking iron supplements containing 50 mg of elemental iron during the first four days of menstrual bleeding in non-anemic women did not change the volume of menstrual bleeding and hemoglobin level.

Characteristics of the hormonal background in women with abnormal uterine bleeding and extragenital disorders

OBJECTIVE

Aim: To establish the peculiarities of the hormonal background in women with abnormal uterine bleeding and extragenital disorders.

PATIENTS AND METHODS

Materials and Methods: The study involved examination of 100 women of reproductive age with concomitant ED and AUB (MG). CG included 50 healthy women. MG women were additionally divided into subgroups depending on the detected pathological changes in the uterine cavity. When examining the hormonal status, concentrations of FSH, LH, estradiol, progesterone, and leptin in BS were determined. Additionally, the level of 25-hydroxyvitamin D ((25-OH) D) was determined.

RESULTS

Results: The decrease in FSH level in subgroups of GP, PSL, EH, EHL was 1.8-2.4 times (KWT, p<0.01). LH in BS of MG patients was statistically lower than that of CG patients (MWT, p=0.0083). The lowest level of LH was registered in patients with EHL, which was 2 times lower than this indicator in CG. A statistically significant increase in the level of estradiol was registered in 73% of MG patients (MWT, p=0.044). The lowest level of progesterone was registered in patients with EHL - 8.40, which is 4.7 times lower than in CG (MWT, p=0.0021). A statistically significant increase in the level of leptin in BS was observed in MG patients (KWT, p=0.0021). The highest level of leptin was found in women with AFP, 2.3 times higher than CG indicators. A statistically significant correlation between the level of leptin and BMI (r=0.86, p=0.011) and a statistically significant (p=0.023) correlation between the level of leptin and estradiol in BS of patients of the examined groups (r=0.42) were revealed. In 87% of MG women, vitamin D deficiency was observed in BS (KWT, p=0.03). A statistically significant (p=0.01) negative correlation between the level of estradiol and vitamin D in the BS of female patients was revealed (r=-0.61, p=0.01).

CONCLUSION

Conclusions: Women of reproductive age with AUB and ED were found to have disorders in the hypothalamic-pituitary-ovarian system. Most patients are characterized by an elevated level of leptin, the concentration of which is closely correlated with BMI, and an elevated level of estradiol is correlated with the level of vitamin D.

The clinical value of serum-related indexes in differentiating simple premature thelarche from idiopathic central precocious puberty

Objective

To explore the changes of serum-related indexes at different time points, so as to identify the critical time of converting from simple premature thelarche (PT) to idiopathic central precocious puberty (ICPP).

Methods

This is a retrospective study. The subjects of the study were 50 girls with PT who were admitted to the Children's Hospital of Hebei Province from January 2019 to September 2020. The enrolled 50 children were divided into the conversion group(n=12) and the non-conversion group(n=38) according to whether PT was converted into ICPP during follow-up. Furthermore, the levels of serum-related indexes and uterine and ovarian volumes were compared after the diagnosis of PT.

Results

The IGF-1 and IGFBP-3 levels of children in the conversion group began to change significantly from six months after the diagnosis, with statistically significant differences when compared with the levels of children at the initial diagnosis, three months and those of the non-conversion group at the same time points (p<0.05). The levels of vitamin-D, DHEA and leptin began to change significantly at nine months after the diagnosis (p<0.05). Besides, uterine and ovarian volumes in the conversion group began to increase significantly six months after the diagnosis, with statistically significant differences when compared with those in the non-conversion group (p<0.05).

Conclusion

Findings in our study suggest that regular monitoring of vitamin-D, IGF-1, IGFBP-3, DHEA and leptin levels, and uterine and ovarian volumes can predict the conversion from PT to ICPP at an early stage.

Serum 25-hydroxyvitamin D levels and the risk of idiopathic central precocious puberty in girls

INTRODUCTION

Prior studies have found inconsistent results regarding the relationship between vitamin D status and Idiopathic Central Precocious Puberty (ICPP).

OBJECTIVE

To assess the role of serum 25-hydroxyvitamin D (25 [OH]D) levels in ICPP development.

METHOD

The authors retrospectively collected data from 221 girls with ICPP and 144 healthy girls between January 2017 and December 2019. The participants' serum 25(OH)D levels were measured using an automatic chemiluminescence method, and the association between serum 25(OH)D levels and the risk of ICPP was assessed using multivariate logistic regression analysis. Odds Ratios (OR) with 95% Confidence Intervals (95% CI) were calculated as effect estimates.

RESULTS

Serum 25(OH)D levels in the ICPP group were significantly lower than those in healthy controls (p < 0.001). Multivariate analysis indicated that girls with insufficient vitamin D levels (OR = 0.201; 95% CI 0.094-0.428; p < 0.001) and sufficient vitamin D levels (OR = 0.141; 95% CI 0.053-0.375; p < 0.001) both had a lower risk of ICPP than girls with vitamin D deficiency. Moreover, the authors found that the height (p = 0.014), weight (p = 0.014), breast stage (p = 0.010), mother's height (p < 0.001), and luteinizing hormone/follicle-stimulating hormone ratio (p = 0.010) in girls with ICPP could be associated with levels of vitamin D.

CONCLUSION

This study found that a low serum 25(OH)D level is an independent risk factor for ICPP, and several characteristics of girls with ICPP could be affected by their vitamin D status.

Serum fat-soluble vitamins and the menstrual cycle in women of childbearing age

Evidence suggests that fat-soluble vitamins are involved in reproduction, but their association with the menstrual cycle, the proxy of female fecundity, remains largely unexplored in women of childbearing age. Serum fat-soluble vitamin levels were measured by HPLC-MS/MS and menstrual cycle data were acquired from 3123 women of reproductive age in Nanjing, China, using standard questionnaires. Irregular and long menstrual cycles occurred in 725 (23.2%) and 604 (19.3%) participants, respectively. Participants with higher levels of vitamins A and K had increased odds of irregular menstrual cycles (vitamin A: OR = 1.39 (95% CI: 1.12, 1.74); vitamin K: OR = 1.41 (95% CI: 1.13, 1.76)) and long menstrual cycles (vitamin A: OR = 1.34 (95% CI: 1.06, 1.69); vitamin K: OR = 1.27 (95% CI: 1.00, 1.61)), and the relationship showed a linear dose-response pattern (P-overall < 0.05, P-nonlinearity > 0.05). Vitamin A was positively associated with the average menstrual cycle length (β: 1.83, 95% CI: 0.28, 3.39). Vitamins A and K were interacted in their associations with irregular menstrual cycles and long cycles. In sensitivity analysis with further exclusion of participants with abnormal thyroid function or a history of polycystic ovary syndrome (PCOS), the association of vitamins A and K with the menstrual cycle remained robust. This study indicates that higher serum vitamin A and K levels in women of childbearing age are significantly associated with higher odds of irregular and long menstrual cycles with a linear dose-response curve. Further investigations are warranted to determine the appropriate fat-soluble vitamin levels for women of childbearing age.

Body Composition Analysis in Perimenopausal Women Considering the Influence of Vitamin D, Menstruation, Sociodemographic Factors, and Stimulants Used

(1) The perimenopausal period and menopause are physiological stages of a woman's life, and they may result in the occurrence of many health problems. The aim of this study was to assess the impact of sociodemographic factors related to the use of stimulants and the presence of menstruation and vitamin D concentration in women's health based on the analysis of their body composition parameters. (2) The study was carried out among 191 women. The diagnostic poll method was used, the levels of serum vitamin D were tested, and a body composition analysis was carried out. (3) Correlations between the vitamin D serum concentration and the following factors were established: adipose tissue mass (%) (rho = -0.18; p = 0.011), visceral adipose tissue (rho = -0.18; p = 0.014), BMI (rho = -0.22; p = 0.002), muscle mass (rho = -0.19; p = 0.008), osseous tissue mass (rho = -0.18; p = 0.013), and the phase angle value (rho = -0.2; p = 0.005). A statistically significant correlation between adipose tissue mass (Mdn = 34.4 vs. 32.2; p = 0.018; η² = 0.029), visceral adipose tissue (Mdn = 8 vs. 6; p = 0.000; η² = 0.106), and metabolic age (Mdn = 49 vs. 42; p = 0.000; η² = 0.098) exists. (4) The following conclusions were made: (i) Menstruating women were characterized by increased body composition parameters, especially adipose tissue mass, visceral adipose tissue, and metabolic age. Greater muscle and osseous masses were noted in regularly menstruating women. (ii) A correlation between the vitamin D concentration and body composition parameters in the studied women was observed.

Correlation between Serum 25-Hydroxyvitamin D Level and Depression among Korean Women with Secondary Amenorrhea: A Cross-Sectional Observational Study

Vitamin D deficiency is considered a major public health problem worldwide and has been reported as having an association with depression. However, studies on the association between vitamin D deficiency and depressive symptoms in secondary amenorrhea (SA) patients are still scarce. This study examined the relationship between serum 25-hydroxyvitamin D (25(OH)D) levels and depressive symptoms among Korean women with SA. In this cross-sectional observational study, 78 patients with SA were initially recruited. Clinical and biochemical parameters, including serum 25(OH)D level, were measured. Data from 63 SA patients who met the study inclusion criteria and completed psychiatric assessments were finally analyzed. We analyzed their association with depression using a hierarchical regression model. The average serum 25(OH)D level was 34.40 ± 24.02 ng/mL, and 41.3% of the women with SA were vitamin D-deficient (<20 ng/mL). The total score of the Korean version of the Hamilton Depression Rating Scale (K-HDRS) was negatively related to serum 25(OH)D levels, free testosterone, and serum anti-Müllerian hormone (AMH) after adjusting for age and BMI (r = −0.450, p < 0.001; r = −0.258, p = 0.045; and r = −0.339, p = 0.006, respectively). Serum 25(OH)D levels and AMH levels were the most powerful predictors of depressive severity when using the K-HDRS in SA patients (β = −0.39, p < 0.005; β = −0.42, p < 0.005, respectively). This study showed that low serum 25(OH)D levels were associated with the severity of depressive symptoms in SA patients. This observation suggests that the evaluation of vitamin D deficiency for the risk of depression may be necessary in patients with SA.

Menstrual changes following COVID-19 infection: A cross-sectional study from Jordan and Iraq

Purpose

COVID-19 infection is normally followed by several post-COVID effects. This study aimed to investigate to evaluate menstrual changes in females following COVID-19 infection, and to evaluate female perception about the effect of COVID-19 on their menstrual cycles.

Methods

During this cross-sectional survey-based study, a convenience sample of 483 women from Jordan and from Iraq, who had infected with COVID-19 were invited to fill-out the study questionnaire.

Results

The study was conducted on the females, with a median age 31 years old. Results showed that 47.2% of them (n = 228) suffered from a change in the number of days between two consecutive periods, as well as from a change in the amount of blood loss. Also, more than 50% of them believed that COVID-19 infection may cause changes in the amount of blood loss during the cycle (n = 375, 56.9%), and changes in the number of days between the two consecutive periods (n = 362, 54.2%).

Regression analysis showed that participants with higher educational level (bachelor or higher) (Beta = -0.114, P = 0.011), and those living in Iraq (Beta = -0.166, P<0.001) believed that COVID-19 has lower tendency to cause menstrual changes. In addition, non-married females (Beta = 0.109, P = 0.017), and those who are current smokers (Beta = 0.091, P = 0.048) believed that COVID-19 has higher tendency to cause menstrual changes.

Conclusion

his study revealed that COVID-19 infection could affect the menstrual cycle for the females. Further prospective studies should be done to confirm these findings and evaluate how long these menstrual irregularities lasted.

Relationship Between Gymnastic Rhythmic Practice and Body Composition, Physical Performance, and Trace Element Status in Young Girls

This study evaluates the influence on body development of doing rhythmic gymnastics in girls from 10 to 17 years of age, the results of certain strength and flexibility abilities, and the trace element status (Ca, Fe, Zn, Cu, Mn, Cr, and Ni). The subjects were divided into three groups: (a) girls who practiced rhythmic gymnastics at a competition level (competition group); (b) girls who practiced this sport at a non-competitive level (training group); and (c) girls who do not practice any sport and with a low level of physical activity (control or sedentary group). Trace element status was determined in hair and urine samples. Results showed that doing rhythmic gymnastics does not alter the normal physical development of muscle mass, and even leads to a decrease in body fat content. Furthermore, better scores in the strength and flexibility test were obtained by the participants of this sports discipline. Statistically significant differences in urine Fe, Cu, and Mn values (p < 0.05) and in hair Cr, Cu, and Mn values (p < 0.05) were found between the two rhythmic gymnastics groups and the control group, and were higher in the competition and training groups. A principal component analysis model was performed to evaluate the possibility of cluster formation among the girls. The PCA results revealed a separation between the different groups although the separation was not perfect. PLS-DA was attempted in order to verify whether it was possible to discriminate between the groups included in this study. It was clear that the competition and control ones were very well classified (around 95% of correct predictions) but 20% of the girls belonging to the training group were misclassified as belonging to the competition one.

Ultraviolet radiation and age at natural menopause in a nationwide, prospective US cohort

BACKGROUND

Solar ultraviolet radiation (UV) is a critical environmental factor for dermal conversion of vitamin D, which is suggested to support reproductive health. However, current epidemiological studies have reported conflicting results on the associations between vitamin D levels and ovarian reserve. Further, few studies have considered UV exposure and reproductive aging, which is closely related to declined ovarian reserve.

OBJECTIVES

We sought to examine the associations of long-term UV exposure and age at natural menopause in a large, nationwide, prospective cohort.

METHODS

Participants in the Nurses' Health Study II (NHS II) who were premenopausal at age 40 were included and followed through 2015. Erythemal UV radiation from a high-resolution geospatial model was linked to the participants' residential histories. Early-life UV was estimated using the reported state of residence at birth, age 15, and age 30. We used time-varying Cox proportional hazards models to estimate the hazard ratio (HR) and 95% confidence intervals (CIs) for natural menopause, adjusting for potential confounders and predictors of menopause.

RESULTS

A total of 63,801 women reported natural menopause across the 1,051,185 person-years of follow-up among 105,631 eligible participants. We found very modest associations with delayed menopause for long-term UV exposure (adjusted HR comparing highest to lowest quartile of cumulative average UV: 0.96, 95% CI: 0.94, 0.99). There was a suggestive inverse association between UV at age 30 with menopause (adjusted HR comparing highest to lowest quartile: 0.97, 95% CI: 0.95, 1.00) but not with UV at birth and age 15.

CONCLUSIONS

Solar UV exposure in adulthood was modestly associated with later onset of menopause. Although consistent with previous findings on vitamin D intake and menopause in the same population, these weak associations found in this study may not be of clinical relevance.

Gender difference in the relationship between anemia and vitamin D in Korean adults: the fifth Korea National Health and Nutrition Examination Survey

This study was conducted to assess the relationship between vitamin D deficiency and anemia, by gender, in Korean adults. The data of 16,060 adults were analyzed (men, 6,840; premenopausal women, 4,916; postmenopausal women, 4,340) from the fifth Korean National Health and Nutrition Examination Survey (KNHANES V) (2010–2012). There were several key findings. First, after adjusting for related variables, the odds ratio (OR) of anemia [hemoglobin (Hb) <13 g/dl in men or Hb <12 g/dl in women] using the vitamin D normal group {25-hydroxyvitamin [25(OH)D] ≥15.0 ng/ml} as reference, was significant for the vitamin D deficient group [25(OH)D <15.0 ng/ml] in the overall population [OR, 1.310; 95% confidence interval (CI), 1.168–1.470]. Second, the OR of anemia, using the vitamin D normal group as reference, was significant for the vitamin D deficient group in premenopausal women (OR, 1.293; 95% CI, 1.105–1.513). However, vitamin D deficiency in the vitamin D normal group in men (OR, 1.093; 95% CI, 0.806–1.484) and postmenopausal women (OR, 1.130; 95% CI, 0.906–1.409) was not significant. In conclusion, Vitamin D deficiency is positively associated with anemia in premenopausal women, but not in men and postmenopausal women.

Hypovitaminosis D in Young Basketball Players: Association with Jumping and Hopping Performance Considering Gender

This study aimed to verify whether a group of young well-trained basketball players presented deficiencies in vitamin D concentration, and to analyze whether there was an association between vitamin D concentration and jumping and hopping performance. Gender differences were considered. Twenty-seven players from an international high-level basketball club (14 female, 16.00 ± 0.55 years; 13 male, 15.54 ± 0.52 years) participated in this cross-sectional study. Rate of force development was evaluated by means of the Abalakov test (bilateral: AbB; right leg: AbR; left leg: AbL); and the triple hop test (right leg: THR; left leg: THL). Blood samples were collected for the determination of serum 25-hydroxyvitamin D and nutritional status. Vitamin D insufficiency was found in both women (29.14 ± 6.08 ng/mL) and men (28.92 ± 6.40 ng/mL), with no gender differences regarding nutritional scores. Jumping and hopping performance was confirmed to be significantly larger in males (AbL, THR, and THL p < 0.005), whose CV% were always smaller. A positive correlation was found between AbB and vitamin D (r = 0.703) in males, whereas this correlation was negative (−0.611) for females, who also presented a negative correlation (r = −0.666) between THR and vitamin D. A prevalence of hypovitaminosis D was confirmed in young elite athletes training indoors. Nutritional (i.e., calciferol) controls should be conducted throughout the season. Furthermore, whilst performance seems to be affected by low levels of this vitamin in men, these deficiencies appear to have a different association with jumping and hopping in women, pointing to different performance mechanisms. Further studies accounting for differences in training and other factors might delve into these gender differences.

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.

Vitamin D-fortified cooking oil is an effective way to improve vitamin D status: an institutional efficacy trial

PURPOSE

High prevalence of vitamin D deficiency (VDD) justifies a cost-effective and sustainable strategy to combat VDD in the community. This study was undertaken for the first time to evaluate the efficacy of daily consumption of vitamin D fortified sunflower oil with a meal.

METHODS

This single-blind trial was conducted in two separate institutions: one as intervention (D-fortified sunflower oil) group (DO, n₁ = 39) and the other as control (unfortified sunflower oil) group (SO, n₂ = 33). Participants consumed their lunches cooked either with D-fortified or unfortified cooking sunflower oil (500 IU/30 g) for 12 weeks. Dietary, anthropometric and biochemical assessments were done for all participants before and after the intervention.

RESULTS

A total of 65 subjects from both sexes aged 32.5 ± 4 years completed the intervention period. Serum 25(OH)D showed a significant increase in DO and a decrease in SO group (8.8 ± 9.3 vs. - 7.4 ± 6.4 ng/mL, p < 0.001). The rise in serum 25(OH)D in DO group was accompanied by a significant decrease in iPTH (DO: - 10.2 ± 29.4 vs. SO: + 9.2 ± 29.5 pg/mL; p = 0.009). A significant reduction in weight (p = 0.004), BMI (p = 0.029), waist girth (p < 0.001), serum total cholesterol (p = 0.0290) and LDL-C (p = 0.010) was observed in DO, as compared with SO group.

CONCLUSIONS

Cooking oil can be considered as an efficacious vehicle for mass fortification program to combat VDD. The improvement of vitamin D status may bring about betterment of certain cardiometabolic risk factors.

REGISTRATION NUMBER

Clinicaltrials.gov: NCT03826654.

Vitamin D metabolites across the menstrual cycle: a systematic review

Background

Accurate estimation of vitamin D status is important for health research and can impact prevention and treatment of deficiency in women of reproductive age. We aimed to assess if blood concentrations of 25-hydroxyvitamin D [25(OH)D] or 1,25-dihydroxyvitamin D [1,25(OH)₂D] change across the menstrual cycle.

Methods

We conducted a systematic search in PubMed, Web of Science, CAB and BIOSIS of literature published until December 2018 which reported concentrations of vitamin D metabolites at two or more identified points among women with regular menstrual cycles.

Results

Ten longitudinal studies met the inclusion criteria; nine studies measured 1,25(OH)₂D and five studies measured 25(OH)D. Study size ranged from 5 to 47 subjects, with an age range of 18–47 years. One study found a decrease in concentration of 25(OH)D in the periovulatory and luteal phase. Four studies found no changes in concentrations of 25(OH)D. Two studies found a rise in 1,25(OH)₂D within the follicular phase, including a 128% increase from day 1 to 15 and a 56% increase from day 0 to 12. Two studies found rises in 1,25(OH)₂D concentrations from the follicular to luteal phase of 13 and 26%. Five studies did not find any changes in concentrations of 1,25(OH)₂D.

Conclusions

No conclusion can be drawn on the pattern of 1,25(OH)₂D concentrations across the normal menstrual cycle due to inconsistencies in study findings. Evidence is currently insufficient to assess 25(OH)D concentrations across the cycle. Future studies should aim to measure 1,25(OH)₂D and 25(OH)D longitudinally, to understand relationships with other hormones and the potential impact on estimates of vitamin D deficiency.