Effects of white European, African Caribbean and South Asian ethnicity on homocysteine levels in patients with systolic heart failure

Ethnic inequalities in multiple long-term health conditions in the United Kingdom: a systematic review and narrative synthesis

Indicative evidence suggests that minoritised ethnic groups have higher risk of developing multiple long-term conditions (MLTCs), and do so earlier than the majority white population. While there is evidence on ethnic inequalities in single health conditions and comorbidities, no review has attempted to look across these from a MLTCs perspective. As such, we currently have an incomplete understanding of the extent of ethnic inequalities in the prevalence of MLTCs. Further, concerns have been raised about variations in the way ethnicity is operationalised and how this impedes our understanding of health inequalities. In this systematic review we aimed to 1) describe the literature that provides evidence of ethnicity and prevalence of MLTCs amongst people living in the UK, 2) summarise the prevalence estimates of MLTCs across ethnic groups and 3) to assess the ways in which ethnicity is conceptualised and operationalised. We focus on the state of the evidence prior to, and during the very early stages of the pandemic. We registered the protocol on PROSPERO (CRD42020218061). Between October and December 2020, we searched ASSIA, Cochrane Library, EMBASE, MEDLINE, PsycINFO, PubMed, ScienceDirect, Scopus, Web of Science, OpenGrey, and reference lists of key studies/reviews. The main outcome was prevalence estimates for MLTCs for at least one minoritised ethnic group, compared to the majority white population. We included studies conducted in the UK reporting on ethnicity and prevalence of MLTCs. To summarise the prevalence estimates of MLTCs across ethnic groups we included only studies of MLTCs that provided estimates adjusted at least for age. Two reviewers screened and extracted data from a random sample of studies (10%). Data were synthesised using narrative synthesis. Of the 7949 studies identified, 84 met criteria for inclusion. Of these, seven contributed to the evidence of ethnic inequalities in MLTCs. Five of the seven studies point to higher prevalence of MLTCs in at least one minoritised ethnic group compared to their white counterparts. Because the number/types of health conditions varied between studies and some ethnic populations were aggregated or omitted, the findings may not accurately reflect the true level of ethnic inequality. Future research should consider key explanatory factors, including those at the macrolevel (e.g. racism, discrimination), as they may play a role in the development and severity of MLTCs in different ethnic groups. Research is also needed to ascertain the extent to which the COVID19 pandemic has exacerbated these inequalities.

Short Sleep Duration Is Associated With Increased Serum Homocysteine: Insights From a National Survey

STUDY OBJECTIVES

Both short sleep duration and increased serum homocysteine levels are associated with cardiovascular events. However, research on the relationship between sleep duration and serum homocysteine levels is sparse. The aim of this study is to examine the association between sleep duration and serum homocysteine levels from a national database.

METHODS

In total, 4,480 eligible participants older than 20 years who had serum homocysteine data and reported sleep duration were enrolled from the US National Health and Nutrition Examination Survey of 2005 to 2006. The association between sleep duration and serum homocysteine levels was analyzed using multivariate regression models for covariate adjustment.

RESULTS

Serum homocysteine level was lowest in individuals with a sleep duration of 7 hours and increased in those with both shorter and longer self-reported total sleep time (groups were categorized into ≤ 5 hours, 6 hours, 7 hours, 8 hours, and ≥ 9 hours). After adjustment for covariates, those in the group sleeping ≤ 5 hours had significantly higher serum homocysteine levels than the reference group (sleep duration of 7 hours). In subgroup analyses by sex, body mass index (BMI), and ethnicity, the association between short sleep duration (≤ 5 hours) and higher serum homocysteine levels persisted in women, individuals with obesity (BMI ≥ 30 kg/m²), and non-Hispanic whites.

CONCLUSIONS

This study highlighted that short sleep duration was associated with higher serum homocysteine levels in women, individuals with obesity (BMI ≥ 30 kg/m²), and non-Hispanic whites; this finding might suggest increased vulnerability to cardiovascular risk or other atherothrombotic events in these groups in the context of short sleep.

Disparities in diabetes mellitus among Caribbean populations: a scoping review

Background

Despite the large body of research on racial/ethnic disparities in health, there are limited data on health disparities in Caribbean origin populations. This review aims to analyze and synthesize published literature on the disparities in diabetes mellitus (DM) and its complications among Afro-Caribbean populations.

Methods

A detailed protocol, including a comprehensive search strategy, was developed and used to identify potentially relevant studies. Identified studies were then screened for eligibility using pre-specified inclusion and exclusion criteria. An extraction form was developed to chart data and collate study characteristics including methods and main findings. Charted information was tagged by disparity indicators and thematic analysis performed. Disparity indicators evaluated include ethnicity, sex, age, socioeconomic status, disability and geographic location. Gaps in the literature were identified and extrapolated into a gap map.

Results

A total of 1009 diabetes related articles/manuscripts, published between 1972 and 2013, were identified and screened. Forty-three studies met inclusion criteria for detailed analysis. Most studies were conducted in the United Kingdom, Trinidad and Tobago and Jamaica, and used a cross-sectional study design. Overall, studies reported a higher prevalence of DM among Caribbean Blacks compared to West African Blacks and Caucasians but lower when compared to South Asian origin groups. Morbidity from diabetes-related complications was highest in persons with low socioeconomic status. Gap analysis showed limited research data reporting diabetes incidence by sex and socioeconomic status. No published literature was found on disability status or sexual orientation as it relates to diabetes burden or complications. Prevalence and morbidity were the most frequently reported outcomes.

Conclusion

Literature on diabetes health disparities in Caribbean origin populations is limited. Future research should address these knowledge gaps and develop approaches to reduce them.

Cardiovascular Risk Profiles amongst Women in a Multiethnic Population in Inner City Britain: A Potential Impact of Anaemia

The risk of diabetes is markedly reduced in men with iron deficiency anaemia (IDA). The nature of this relationship in women is not clear, nor is there information about the influence of ethnicity, given the increased susceptibility of diabetes amongst South Asians and Afro-Caribbeans. We reviewed 3563 patients with a diagnosis of anaemia from 2000 to 2007. The age-adjusted prevalence of vitamin B12 deficiency and IDA was calculated, together with cardiovascular comorbidities amongst Caucasians, South Asians, and Afro-Caribbeans. The prevalence of vitamin B12 deficiency (women only) or IDA was markedly higher in South Asians compared to Caucasians and Afro-Caribbeans. Among women with IDA, diabetes was more prevalent among South Asians (45%, 95% CI 39.0-51.0) compared to Caucasians (3.0%, 2.1-4.0); P < 0.001. Among South Asian women with vitamin B12 deficiency, the prevalence of diabetes was reduced 8.5% (5.2-12.0). South Asian women with vitamin B12 deficiency had a higher prevalence of myocardial infarction (MI) and ischemic heart disease (IHD), but this relationship was reversed in IDA. IDA is associated with a greater prevalence of diabetes in South Asian women, but it is not coordinated by a greater risk of macrovascular complications. Given the cardiovascular impact of diabetes in South Asians, this association merits further study in relation to its pathophysiological implication.

Heart failure among South Asians: a narrative review of risk, nature, outcomes and management

Individuals of South Asian descent have a high prevalence of comorbidities that are risk factors for the development of heart failure (HF), including diabetes mellitus and metabolic syndrome. However, little is known about the prevalence of HF, its management and prognosis for this population compared to Caucasians. Therefore, a literature review relating to the nature, outcome and treatment of HF in South Asian patients compared to Caucasians was conducted. It was anticipated that collating existing studies in this manner would be useful for guiding professionals in managing HF within this ethnic group, given that to achieve optimal care, regimens need to take into account cultural differences that may impact on adherence. Reviewed literature showed that South Asians with HF were more likely to be younger and have diabetes and hypertension. These papers also implied that outcomes for South Asians with HF were similar or even better than for Caucasians. The review highlighted the under-representation of South Asians in HF trials, meaning that evidence-based recommendations tailored to this specific population are limited. This is an important consideration because ethnic differences in response to medication have been reported; it cannot be assumed that treatments shown to work for Caucasians will be efficacious for those from minority ethnic groups.

The role of B vitamins in the management of heart failure

Heart failure (HF) is the leading cause of morbidity and mortality in industrialized countries, creating a significant burden on both the healthcare system and quality of life. Research efforts continue to explore new pharmaceutical or surgically based approaches to HF management, but the role of nutrition as an adjunct therapy has been largely ignored. Elderly age, anorexia, malabsorption, premature satiety, and disease severity are among the factors identified as contributing to reduced nutrient intakes in patients with HF. These factors suggest that patients with HF are at increased risk of multiple-nutrient deficiencies, including B vitamins. B vitamins may be of particular therapeutic interest because of their key roles as cofactors in energy-producing pathways. Recently, impaired stores of high-energy compounds have been linked with myocardial dysfunction and prognosis in patients with HF. Therefore, deficiencies of B vitamins might contribute to reduced energy stores and disease progression. This review summarizes the existing literature both with respect to the prevalence of B vitamin deficiency as well as evidence from supplementation trials in patients with HF. The findings suggest that most of the literature in this area has focused on thiamin deficiency in patients with HF, whereas other B vitamins remain largely unstudied. Although few sporadic trials suggest a role for B vitamins in the management of HF, none are conclusive. Therefore, there is a need for larger, more robust trials to assist in defining the B vitamin requirements as well as the impact of supplementation on both morbidity and mortality in patients with HF.

Systolic heart failure in South Asians

Heart failure (HF) is a common condition leading to an unfavourable prognosis and impaired quality of life. In this review, we provide an overview of published literature on possible epidemiological and pathophysiological differences between patients with systolic HF of South Asian origin and those from other ethnic groups (mainly White). Systolic HF tends to manifest earlier among South Asians and with frequent hospital admissions. However, survival for such patients appears to be significantly better compared with the White group, which might be associated with different patterns of HF. For example, this could be attributed to a lower prevalence of left ventricular systolic dysfunction in South Asian subjects. Indeed, the high prevalence of hypertension and diabetes among South Asians may predispose to diastolic HF with preserved systolic function. In addition, because of underrepresentation of South Asians in clinical trials, there are little data on optimal management of this ethnic group.

Candidate genetic variants in the fibrinogen, methylenetetrahydrofolate reductase, and intercellular adhesion molecule-1 genes and plasma levels of fibrinogen, homocysteine, and intercellular adhesion molecule-1 among various race/ethnic groups: data from the Women's Genome Health Study

BACKGROUND

Although inflammation is a core element of atherogenesis and plasma levels of fibrinogen (FGB), homocysteine, and intercellular adhesion molecule-1 (ICAM-1) differ by race/ethnicity, little is known about the role of genetic polymorphisms in the FGB, methylenetetrahydrofolate reductase (MTHFR), and ICAM-1 genes in determining plasma levels of these biomarkers. We examined the relationship between specific polymorphisms in the FGB, homocysteine, and ICAM-1 genes and their respective inflammatory biomarker concentrations at baseline in women from different race/ethnic groups.

METHODS

We genotyped specific polymorphisms in FGB (-455G>A/rs1800790), MTHFR (677C>T/rs1801133), and ICAM-1 (Lys56Met/rs5491 and Gly241Arg/rs1799969) at baseline and evaluated their relationship with respective inflammatory biomarker levels in 25,565 white, 476 African-American (black), 277 Hispanic, and 370 Asian women participating in the Women's Genome Health Study.

RESULTS

Overall, the minor allele frequencies for -455G>A were similar among white, Hispanic, and Asian women (17.2%-21.9%) but significantly lower in black women (6.6%, P < .001). The minor allele was associated with elevated FGB levels only in whites and Asians. After adjustment for age, body mass index, smoking, postmenopausal status, diabetes, hormone replacement therapy use, hypertension, and education, black women had the highest FGB levels compared to other race/ethnic groups. The minor allele frequency of the MTHFR 677C>T polymorphism was lowest in blacks (blacks 12.1%, whites 33.1%, Hispanics 39.0%, Asians 24.0%), and the T allele was only significantly associated with homocysteine levels in white women. Among whites, Hispanics, and Asians, the Lys56Met polymorphism was rare compared to the frequency in blacks (P < .001). Neither the Lys56Met nor Gly241Arg polymorphisms were common in Asians. Nonetheless, both polymorphisms were generally associated with lower ICAM-1 levels; the lowest levels were observed in black women.

CONCLUSION

We found significant associations between certain candidate genetic polymorphisms and baseline plasma levels of FGB, homocysteine, and ICAM-1 in women from various race/ethnic groups. The present investigation is hypothesis generating and suggests genetic determination of differential concentrations of these atherosclerosis-related inflammatory biomarkers differ among various race/ethnic groups.