Associations between medication use and homocysteine levels in an older population, and potential mediation by vitamin B12 and folate: data from the B-PROOF Study

A micronutrient supplement modulates homocysteine levels regardless of vitamin B biostatus in elderly subjects

Elevated homocysteine (Hcy) levels (≥15 μmol/L) in the elderly are frequently associated with a higher risk of cardiovascular disease and cognitive decline. Several studies have already shown an Hcy-lowering effect of B vitamin supplementation in cohorts deficient in these nutrients. The aim of this randomized, double-blinded 12-week intervention study was to investigate whether Hcy levels in healthy elderly subjects (75.4±4.5 years, n=133) could be lowered with a micronutrient supplement (i.e., 400 μg folic acid, 100 μg cobalamin). Difference in mean initial Hcy levels between intervention (17.6±7.1 μmol/L, n=65) and placebo group (18.9±6.1 μmol/L, n=68) was not significant. The prevalence of cobalamin and folate deficiency in the total study population was low: 27% had serum-cobalamin levels ≤150 pmol/L, 12% holo-transcobalamin (Holo-TC) levels ≤50 pmol/L, 13% low cobalamin status using the aggregated cobalamin marker 4cB12 and 10% red blood cell (RBC) folate ≤570 nmol/L. Nevertheless, the treated subjects still showed improved cobalamin and folate biostatus (serum cobalamin Δt12-t0: 63±48 pmol/L; Holo-TC Δt12-t0: 17±19 pmol/L; RBC folate Δt12-t0: 326±253 nmol/L) and Hcy levels (Δt12-t0: -3.6±5.7 μmol/L). The effects were statistically significant compared to the placebo group with p=0.005 (serum cobalamin), p=0.021 (Holo-TC), p=0.014 (RBC-folate) and p<0.001 (Hcy). The Hcy-lowering effect was dependent on the initial Hcy levels (p<0.001). Our findings suggest that elevated Hcy levels in elderly subjects can be lowered regardless of the initial cobalamin and folate biostatus.

Homocysteine levels, H-Hypertension, and the MTHFR C677T genotypes: A complex interaction

Background and objectives

High homocysteine levels are associated with increased risk of hypertension and stroke. Homocysteine is metabolized by the methylenetetrahydrofolate reductase (MTHFR). We aimed to investigate the levels of homocysteine and their association with hypertension, stroke, and antihypertensive medication usage in patients with different MTHFR C677T genotypes.

Methods and results

Genotype frequency of MTHFR polymorphism was performed, and plasma homocysteine levels were measured in 2,640 adult Lebanese patients. Hypertension, history of stroke, and list of medications were documented, among other clinical and demographic parameters. The TT mutant genotype and the T mutant allele of MTHFR were more prevalent in hyperhomocysteinemia (HHcy) and H-hypertensive (H-HTN, defined as hypertension with hyperhomocysteinemia) patients when compared to non-HHcy subjects and non H-HTN patients respectively. Homocysteine levels were significantly higher in hypertensive patients specifically among those on diuretics. A higher level of homocysteine was found in hypertensive patients with the MTHFR T allele compared to patients carrying the C allele. Among the T allele carriers, the average plasma homocysteine level was 13.3 ± 0.193 μmol/L for hypertensive subjects compared to 11.9 ± 0.173 μmol/L (non-hypertensives). Furthermore, homocysteine levels significantly correlated with stroke risk in patients with the T alleles.

Conclusions

We found an association of homocysteine with hypertension, hypertensive medication, and stroke risk among patients with the MTHFR T allele and the TT genotype. The association of diuretics therapy with higher homocysteine levels calls for routine measurements and therapeutic control of homocysteine in patients on diuretic, to improve health-related outcomes.

A Propensity Score Matched Approach to Assess the Associations of Commonly Prescribed Medications with Fall Risk in a Large Harmonized Cohort of Older Ambulatory Persons

Introduction

Several medication classes are considered to present risk factors for falls. However, the evidence is mainly based on observational studies that often lack adequate adjustment for confounders. Therefore, we aimed to assess the associations of medication classes with fall risk by carefully selecting confounders and by applying propensity score matching (PSM).

Methods

Data from several European cohorts, harmonized into the ADFICE_IT cohort, was used. Our primary outcome was time until the first fall within 1-year follow-up. The secondary outcome was a fall in the past year. Our exposure variables were commonly prescribed medications. We used 1:1 PSM to match the participants with reported intake of specific medication classes with participants without. We constructed Cox regression models stratified by the pairs matched on the propensity score for our primary outcome and conditional logistic regression models for our secondary outcome.

Results

In total, 32.6% of participants fell in the 1-year follow-up and 24.4% reported falling in the past year. ACE inhibitor users (prevalence of use 15.3%) had a lower fall risk during follow-up when matched to non-users, with a hazard ratio (HR) of 0.82 (95% CI 0.68–0.98). Also, statin users (prevalence of use 20.1%) had a lower risk, with an HR of 0.76 (95% CI 0.65–0.90). Other medication classes showed no association with risk of first fall. Also, in our secondary outcome analyses, statin users had a significantly lower risk. Furthermore, β-blocker users had a lower fall risk and proton pump inhibitor use was associated with a higher risk in our secondary outcome analysis.

Conclusion

Many commonly prescribed medication classes showed no associations with fall risk in a relatively healthy population of community-dwelling older persons. However, the treatment effects and risks can be heterogeneous between individuals. Therefore, focusing on identification of individuals at risk is warranted to optimize personalized falls prevention.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40266-021-00876-0.

Long-term effects of folic acid and vitamin-B12 supplementation on fracture risk and cardiovascular disease: Extended follow-up of the B-PROOF trial

BACKGROUND & AIMS

In the initial B-proof, we found inconsistent results of B vitamin supplementation. However, the debate regarding the effects of B vitamins on age-related diseases continues. Therefore, our aim was to investigate the long-term effects (5-7 years follow-up) of an intervention with folic acid and vitamin-B12 supplementation on fracture and cardiovascular disease risk.

METHODS

Extended follow-up of the B-PROOF trial, a multi-center, double-blind randomized placebo-controlled trial designed to assess the effect of 2-3 years daily supplementation with folic acid (400 μg) and vitamin-B12 (500 μg) versus placebo (n = 2,919). Primary outcome was verified self-reported fracture incidence and secondary outcomes were self-reported cardiovascular endpoints, which were collected through a follow-up questionnaires Proportional hazard analyses was used for the effect of the intervention on risk of fracture(s) and logistic regression for the effect of the intervention on risk of cardiovascular disease.

RESULTS

A total of 1,298 individuals (44.5%) participated in the second follow-up round with median of 54 months [51-58], (n = 662 and n = 636, treatment versus placebo group). Median age at baseline was 71.0 years [68.0-76.0] for both groups. No effect was observed of the intervention on osteoporotic fracture or any fracture risk after a follow-up (HR: 0.99, 95% CI: 0.62-1.59 and HR: 0.77; 95% CI: 0.50-1.19, respectively), nor on cardiovascular or cerebrovascular disease risk (OR: 1.05; 95%CI: 0.80-1.44 and OR: 0.85; 95%CI: 0.50-1.45, respectively). Potential interaction by baseline homocysteine concentration was observed for osteoporotic- and any fracture (p = 0.10 and 0.06 respectively), which indicated a significantly lower risk of any fracture in the treatment group with higher total homocysteine concentrations (>15.1 μmol/l). No age-dependent effects were present.

CONCLUSIONS

This study supports and extends previous null-findings of the B-PROOF trial and shows that supplementation of folic acid and vitamin-B12 has no effect on fracture risk, nor on cardiovascular disease in older individuals over a longer follow-up period. However, B-vitamin supplementation may be beneficial in reducing fractures in individuals with high total homocysteine concentrations, a finding which needs to be replicated.

Voluntary fortification is ineffective to maintain the vitamin B12 and folate status of older Irish adults: evidence from the Irish Longitudinal Study on Ageing (TILDA)

Mandatory fortification of staple grains with folic acid and/or vitamin B12 (B12) is under debate in many countries including Ireland, which has a liberal, but voluntary, fortification policy. Older adults can be at risk of both deficiency and high folate status, although little is known on the actual prevalence and the major predictors. Population prevalence estimates from older adults (n 5290 ≥50 years) from the Irish Longitudinal Study on Ageing (TILDA) (Wave 1) are presented here. Measures included plasma total vitamin B12 and folate, whereas predictors included detailed demographic, socio-economic, geographic, seasonal and health/lifestyle data. The prevalence of deficient or low B12 status (45 nmol/l) was observed in 8·9 %, whereas high B12 status was observed in 3·1 % (>601 pmol/l). The largest positive predictor of B12 concentration was self-reported B12 injection and/or supplement use (coefficient 51·5 pmol/; 95 % CI 9·4, 93·6; P=0·016) followed by sex and geographic location. The largest negative predictor was metformin use (-33·6; 95 % CI -51·9, -15·4; P<0·0001). The largest positive predictor of folate concentration was folic acid supplement use (6·0; 95 % CI 3·0, 9·0 nmol/l; P<0·001) followed by being female and statin medications. The largest negative predictor was geographic location (-5·7; 95 % CI -6·7, -4·6; P<0·0001) followed by seasonality and smoking. B-vitamin status in older adults is affected by health and lifestyle, medication, sampling period and geographic location. We observed a high prevalence of low B12 and folate status, indicating that the current policy of voluntary fortification is ineffective for older adults.

Metformin and Breast Cancer: Molecular Targets

Metformin has been the first-line drug for the treatment of type II diabetes mellitus for decades, being presently the most widely prescribed antihyperglycemic drug. Retrospective studies associate the use of metformin with a reduction in cancer incidence and cancer-related death. However, despite extensive research about the molecular effects of metformin in cancer cells, its mode of action remains controversial. The major molecular targets of metformin include complex I of the mitochondrial electron transport chain, adenosine monophosphate (AMP)-activated protein kinase (AMPK), and mechanistic target of rapamycin complex 1 (mTORC1), but AMPK-independent effects of metformin have also been described. Breast cancer is one of the leading causes of cancer-related morbidity and mortality among women worldwide. Several studies have reinforced a link between breast cancer risk and diabetes. Moreover, metformin significantly reduces breast cancer risk, compared to patients who are not using metformin and is independent of diabetes status. In this review, we summarize the current molecular evidence to elucidate metformin's mode of action against breast cancer cells.

Elevated plasma homocysteine upon ischemic stroke is associated with increased long-term mortality in women

BACKGROUND

Ischemic stroke is a leading cause of death worldwide, despite preventive and therapeutic advances during the last twenty years. Blood-borne biomarkers have been studied in association to short- and long-term outcome, in order to investigate possible modifiable predictors of disability and death. Increased homocysteine has been associated with increased vascular risk and unfavorable outcome, but homocysteine lowering treatment has not consistently been successful in risk reduction. The aim of this study was to investigate homocysteine levels upon acute ischemic stroke in association to long-term mortality.

METHODS

Of 622 patients included in our hospital-based registry, 331 survived the first month after admission, and had a diagnosis of ischemic stroke and available homocysteine values. All-cause and vascular mortality were investigated based on the national patient- and cause of death-registries. Survival analysis and Cox proportional hazard models were used to investigate time to death and predictors of outcome.

RESULTS

Of 331 patients, 148 (45%) had low homocysteine (<13 micromol/L) and 183 (55%) had high homocysteine (> = 13 micromol/L). During 10 years of follow-up (median 5.5 years), 47 patients (32%) with low homocysteine and 94 (51%) with high homocysteine died (p<0.0001). Estimated median survival was not reached for the low homocysteine group, and was 80 months in the high homocysteine group (p with log-rank test 0.002). High homocysteine was not independently associated with increased risk for death after adjustment for age, sex, comorbidities, and eGFR (HR 1.29, 95% CI 0.86-1.93; p = 0.2). Subgroup analysis by sex showed that high homocysteine was an independent predictor of mortality in women after adjustment for age and vascular comorbidities (HR 1.85; 95% CI 1.03-3.31; p = 0.04), but not in men (HR 0.87; 95% CI 0.52-1.43; p = 0.6).

CONCLUSION

Increased plasma homocysteine (> = 13 micromol/L) upon acute ischemic stroke was not independently associated with mortality in our study. In the subgroup of women, high homocysteine was associated with increased five-year risk of death. Our study's retrospective design and the exploratory nature of subgroup analysis, prevent robust conclusions based on that observation. Future studies on homocysteine levels before as well as upon stroke will shed further light on a possible causal association.

Metformin Treatment and Homocysteine: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The aim of this systematic review is to assess whether metformin could change the concentration of serum homocysteine (Hcy) with and without simultaneous supplementation of B-group vitamins or folic acid. A literature search was conducted in PubMed, EmBase, and Cochrane Central Register of Controlled Trials (CENTRAL) to identify randomized controlled trials (RCTs) reporting the concentration of serum Hcy in metformin-treated adults. Meta-analysis was applied to assess the association between metformin and the changes of Hcy concentration. Twelve publications were included in this study. In the overall analysis, metformin administration was not statistically associated with the change of Hcy when compared with the control treatment (mean difference (MD), 0.40 μmol/L; 95% confidence interval (CI), -0.07~0.87 μmol/L, p = 0.10). In the subgroup analysis, metformin was significantly associated with an increased concentration of Hcy in the absence of exogenous supplementation of folic acid or B-group vitamins (MD, 2.02 μmol/L; 95% CI, 1.37~2.67 μmol/L, p < 0.00001), but with a decreased concentration of serum Hcy in the presence of these exogenous supplementations (MD, -0.74 μmol/L; 95% CI, -1.19~-0.30 μmol/L, p = 0.001). Therefore, although the overall effect of metformin on the concentration of serum Hcy was neutral, our results suggested that metformin could increase the concentration of Hcy when exogenous B-group vitamins or folic acid supplementation was not given.

Metformin and cancer: Between the bioenergetic disturbances and the antifolate activity

For decades, metformin has been the first-line drug for the treatment of type II diabetes mellitus, and it thus is the most widely prescribed antihyperglycemic drug. Retrospective studies associate the use of metformin with a reduction in cancer incidence and cancer-related death. However, despite extensive research about the molecular effects of metformin in cancer cells, its mode of action remains controversial. In this review, we summarize the current molecular evidence in an effort to elucidate metformin's mode of action against cancer cells. Some authors describe that metformin acts directly on mitochondria, inhibiting complex I and restricting the cell's ability to cope with energetic stress. Furthermore, as the drug interrupts the tricarboxylic acid cycle, metformin-induced alteration of mitochondrial function leads to a compensatory increase in lactate and glycolytic ATP. It has also been reported that cell cycle arrest, autophagy, apoptosis and cell death induction is mediated by the activation of AMPK and Redd1 proteins, thus inhibiting the mTOR pathway. Additionally, unbiased metabolomics studies have provided strong evidence to support that metformin alters the methionine and folate cycles, with a concomitant decrease in nucleotide synthesis. Indeed, purines such as thymidine or hypoxanthine restore the proliferation of tumor cells treated with metformin in vitro. Consequently, some authors prefer to refer to metformin as an "antimetabolite drug" rather than a "mitochondrial toxin". Finally, we also review the current controversy concerning the relationship between the experimental conditions of in vitro-reported effects and the plasma concentrations achieved by chronic treatment with metformin.

Carotid hemodynamics is associated with monocyte count determined by serum homocysteine level in patients with essential hypertension

To examine the association between pulsatility index (PI) in the common carotid artery (CCA) as a marker of vascular resistance and cardiovascular risk factors, including serum homocysteine and inflammation, 67 hypertensive patients were enrolled. PI correlated with homocysteine and interleukin-6, monocyte count, gender, age and BMI, with monocyte count and age being independent determinants for PI. In turn, monocyte count correlated with homocysteine, tumor necrosis factor-alpha, and HDL-cholesterol, BMI, and gender, with HDL-cholesterol and homocysteine being independent determinants for monocyte count. These results indicated monocyte count determined by homocysteine is associated with arterial stiffness in hypertensive patients.