Age, menopausal status and homocysteine levels in women around menopause

Association between dietary folate intake and the risk of osteoporosis in adults: a cross-sectional study

BACKGROUND

Increased intake of specific vitamins has been linked to a decreased prevalence of osteoporosis. However, the association between dietary folate intake and the risk of osteoporosis in the general population remains incompletely understood. Therefore, we aimed to determine the association between dietary folate intake and the risk of osteoporosis in the general population of the USA.

METHODS

In this cross-sectional study, data from the National Health and Nutrition Examination Survey (2017-2020) were collected. Osteoporosis was considered to be indicated by a bone mineral density greater than 2.5 standard deviations below the mean of the young adult reference group. Dietary folate intake was measured by a 24-hour dietary recall. Multivariate logistic regression models and restricted cubic spline models were used.

RESULTS

The study included 2297 participants (mean age: 63.69 ± 0.35 years), 49.92% of whom were female. In the general population, increased dietary folate intake was directly associated with a decreased risk of osteoporosis (P for trend = 0.005). In the age > 60 years and female subgroups, folate intake was inversely associated with the risk of osteoporosis (P for trend < 0.001). The dose‒response curve suggested that this association was nonlinear (P for nonlinearity = 0.015).

CONCLUSIONS

Our cross-sectional study provides initial insights into the inverse association between dietary folate intake and the risk of osteoporosis in the general U.S.

POPULATION

Further research is needed to confirm these associations.

The protective effects of the methylenetetrahydrofolate reductase rs1801131 variant among Saudi smokers

Methylenetetrahydrofolate reductase (MTHFR) polymorphism plays a fundamental role in susceptibility to various diseases, including cancers and autoimmune diseases. In the current study, we aimed to compare genotype and allele frequency variations of rs1801131, one of the most common variants found in the MTHFR gene, among Saudi smokers and non-smokers. We hypothesized that genetic variations of this gene are responsible for many diseases, particularly those caused by cigarette smoking (CS) such as pulmonary diseases, oral cancer and lung cancer. We performed a case-control study on a sample of 235 healthy smokers and 239 healthy non-smokers in Saudi Arabia. The rs1801131 SNP genotypes were determined using a genotyping assay and multiple in silico algorithmic software programs were used to identify the effects and structural functions of the rs1801131 (Glu429Ala) mutation. Using chi-squared tests, we found that, among smokers, TG and GG genotype carriers had 0.209-fold (OR = 0.209, P < 0.005) and 0.427-fold (OR = 0.427, P = 0.003) lower risks of CS-related disease compared to TT reference genotypes. In addition, this protective effect was observed in Saudi smokers independent of age, gender, types of smoking, duration, and average daily smoking consumption. Filling a research gap by exploring this topic in the Saudi population, the current findings indicate that genotype and allele distributions of MTHFR rs1801131 polymorphism present fundamental protective effects against the risk of CS-related disease. These findings should be verified in future studies with larger sample sizes, different ethnicities, and patients suffering from CS-related diseases, such as oral cancer and lung cancer.

Neuroprotective and neurotoxic outcomes of androgens and estrogens in an oxidative stress environment

BACKGROUND

The role of sex hormones on cellular function is unclear. Studies show androgens and estrogens are protective in the CNS, whereas other studies found no effects or damaging effects. Furthermore, sex differences have been observed in multiple oxidative stress-associated CNS disorders, such as Alzheimer's disease, depression, and Parkinson's disease. The goal of this study is to examine the relationship between sex hormones (i.e., androgens and estrogens) and oxidative stress on cell viability.

METHODS

N27 and PC12 neuronal and C6 glial phenotypic cell lines were used. N27 cells are female rat derived, whereas PC12 cells and C6 cells are male rat derived. These cells express estrogen receptors and the membrane-associated androgen receptor variant, AR45, but not the full-length androgen receptor. N27, PC12, and C6 cells were exposed to sex hormones either before or after an oxidative stressor to examine neuroprotective and neurotoxic properties, respectively. Estrogen receptor and androgen receptor inhibitors were used to determine the mechanisms mediating hormone-oxidative stress interactions on cell viability. Since the presence of AR45 in the human brain tissue was unknown, we examined the postmortem brain tissue from men and women for AR45 protein expression.

RESULTS

Neither androgens nor estrogens were protective against subsequent oxidative stress insults in glial cells. However, these hormones exhibited neuroprotective properties in neuronal N27 and PC12 cells via the estrogen receptor. Interestingly, a window of opportunity exists for sex hormone neuroprotection, wherein temporary hormone deprivation blocked neuroprotection by sex hormones. However, if sex hormones are applied following an oxidative stressor, they exacerbated oxidative stress-induced cell loss in neuronal and glial cells.

CONCLUSIONS

Sex hormone action on cell viability is dependent on the cellular environment. In healthy neuronal cells, sex hormones are protective against oxidative stress insults via the estrogen receptor, regardless of sex chromosome complement (XX, XY). However, in unhealthy (e.g., high oxidative stress) cells, sex hormones exacerbated oxidative stress-induced cell loss, regardless of cell type or sex chromosome complement. The non-genomic AR45 receptor, which is present in humans, mediated androgen's damaging effects, but it is unknown which receptor mediated estrogen's damaging effects. These differential effects of sex hormones that are dependent on the cellular environment, receptor profile, and cell type may mediate the observed sex differences in oxidative stress-associated CNS disorders.

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.

Sex-related differences in oxidative stress and neurodegeneration

Oxidative stress has been implicated in a number of neurodegenerative diseases spanning various fields of research. Reactive oxygen species can be beneficial or harmful, depending on their concentration. High levels of reactive oxygen species can lead to oxidative stress, which is an imbalance between free radicals and antioxidants. Increased oxidative stress can result in cell loss. Interestingly, sex differences have been observed in oxidative stress generation, which may underlie sex differences observed in neurodegenerative disorders. An enhanced knowledge of the role of sex hormones on oxidative stress signaling and cell loss can yield valuable information, leading to sex-based mechanistic approaches to neurodegeneration.

Novel relationships between B12, folate and markers of inflammation, oxidative stress and NAD(H) levels, systemically and in the CNS of a healthy human cohort

OBJECTIVE

To evaluate the relationship between folate, cobalamin (Cbl), and homocysteine (Hcy), and markers of inflammation and oxidative stress within the periphery and central nervous system (CNS) of a healthy human cohort.

METHODS

Thirty-five matched cerebrospinal fluid (CSF) and plasma samples were collected from consenting participants who required a spinal tap for the administration of anaesthetic. Plasma concentrations of Hcy and both plasma and CSF levels of folate, Cbl, nicotinamide adenine dinucleotide (NAD(H)) and markers of inflammation (interleukin-6, IL-6), and oxidative stress (F2-isoprostanes, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and total antioxidant capacity (TAC)) were quantified.

RESULTS

In the peripheral circulation, positive associations were observed between plasma folate and Cbl, and plasma TAC (P ≤ 0.01; P ≤ 0.01) and plasma NAD(H) (P ≤ 0.05; P ≤ 0.05) levels, respectively. Plasma folate was inversely associated with plasma Hcy concentrations (P ≤ 0.05); however, no statistically significant relationships were observed between plasma Hcy and plasma markers of inflammation, oxidative stress, or [NAD(H)]. Within the CNS plasma Hcy correlated positively with CSF IL-6 (P ≤ 0.01) and negatively with CSF NAD(H) (P ≤ 0.05) concentrations. An inverse association was observed between CSF folate and CSF levels of IL-6 (P ≤ 0.05). Unexpectedly, a positive association between CSF Cbl and CSF 8-OHdG levels was also found (P ≤ 0.01).

DISCUSSION

These results indicate that folate and Cbl concentrations may influence the levels of oxidative damage, inflammation, and NAD(H), both systemically and within the CNS.

Serum homocysteine and asymmetric dimethylarginine levels in patients with premature ovarian failure: a prospective controlled study

OBJECTIVE

To investigate serum homocysteine and asymmetric dimethylarginine (ADMA) levels in patients with premature ovarian failure (POF).

STUDY DESIGN

A total of 69 women, 32 with POF and 37 apparently healthy women were included in the study. Fasting blood samples were drawn to measure serum homocysteine and ADMA levels using ELISA method.

RESULTS

The study and control group had a mean age of 37.3 + 2.6, 37.5 + 2.5 years; a mean homocysteine level of 13.54 + 5.19, 12.71 + 3.99 mmol/l and a mean ADMA level of 1.32 + 0.27, 1.26 + 0.36 mmol/l, respectively. There were no statistically significant differences between the two groups in terms of homocysteine and ADMA levels (with p values of 0.465 and 0.423, respectively). A negative significant correlation was found between estradiol and ADMA (p <0.05).

CONCLUSION

Homocysteine and ADMA levels did not change in comparison with the control group, which suggests that estrogen deficiency in patients with POF does not have any effect on homocysteine and asymmetric dimethylarginine levels.

Relation of folates, vitamin B12 and homocysteine to vertebral bone mineral density change in postmenopausal women. A five-year longitudinal evaluation

Elevation of homocysteine is associated with an increased risk for bone fractures. Whether the risk is due to homocysteine or to the reduced levels of cofactors necessary for its metabolisation, such as folates or vitamin B12, is not completely clear. In this study we wanted to determine whether in postmenopausal women, levels of folates, homocysteine or vitamin B12 are predictive of the rate of vertebral bone mineral density (BMD) change. The study was conducted at the centre for the menopause of our university hospital. Between September 2001 and March 2002, 161 healthy postmenopausal women volunteered for a cross-sectional evaluation of BMD and levels of serum folates, homocysteine and vitamin B12. Women were recalled for a second evaluation of vertebral BMD after about 5 years. Women having used anti-resorptive therapies for more than 1 year were excluded. The analysis was possible in 117 postmenopausal women. The annual rate of vertebral BMD change was independently related to levels of folates (coefficient of regression (CR): 2.040; 95%CI: 0.483, 3.596; p=0.011), and initial BMD values (CR: -0.060; 95%CI: -0.117, -0.003; p=0.040). No significant relation was found between the change of vertebral BMD and homocysteine or vitamin B12. BMD values at the first (r=0.225; p=0.016) and the second (r=0.206; p=0.027) evaluation were related to levels of folates, but not of homocysteine or of vitamin B12. These data suggest an important role for folates deficiency in the vertebral BMD decline of postmenopausal women.

Effects of estrogen and estrogen-progestogen therapy on homocysteine levels and their correlation with carotid vascular resistance

OBJECTIVE

To evaluate the correlation between homocysteine levels and carotid vascular resistance in menopausal women submitted to estrogen and estrogen-progestogen therapy.

METHODS

Eighty-six women with a mean age of 52 years were enrolled in a prospective, randomized, double-blind, 6-month study. Patients were allocated to use one of three oral therapies: placebo (n = 26), micronized estradiol 2 mg/day (n = 30) or micronized estradiol 2 mg/day plus norethisterone acetate 1 mg/day (n = 30). Evaluation of homocysteine levels and Doppler sonography of the common carotid artery, used to calculate pulsatility index (PI), were carried out prior to initiating therapy and at the end of the study. The correlation between these two parameters was evaluated using Pearson's coefficient of correlation.

RESULTS

There was a significant reduction in homocysteine levels in the groups treated with estrogen alone or estrogen combined with norethisterone. PI was significantly lower only in users of estrogen alone; however, no significant correlation was found between homocysteine measurements and PI.

CONCLUSION

No significant correlation was found between homocysteine levels and carotid vascular resistance following hormone therapy.