Metals are known endocrine disruptors and have been linked to cardiometabolic diseases via multiple potential mechanisms, yet few human studies have both the exposure variability and biologically-relevant phenotype data available. We sought to examine the distribution of metals exposure and potential associations with cardiometabolic risk factors in the “Modeling the Epidemiologic Transition Study” (METS), a prospective cohort study designed to assess energy balance and change in body weight, diabetes and cardiovascular disease risk in five countries at different stages of social and economic development.
Young adults (25–45 years) of African descent were enrolled (N = 500 from each site) in: Ghana, South Africa, Seychelles, Jamaica and the U.S.A. We randomly selected 150 blood samples (N = 30 from each site) to determine concentrations of selected metals (arsenic, cadmium, lead, mercury) in a subset of participants at baseline and to examine associations with cardiometabolic risk factors.
Median (interquartile range) metal concentrations (μg/L) were: arsenic 8.5 (7.7); cadmium 0.01 (0.8); lead 16.6 (16.1); and mercury 1.5 (5.0). There were significant differences in metals concentrations by: site location, paid employment status, education, marital status, smoking, alcohol use, and fish intake. After adjusting for these covariates plus age and sex, arsenic (OR 4.1, 95% C.I. 1.2, 14.6) and lead (OR 4.0, 95% C.I. 1.6, 9.6) above the median values were significantly associated with elevated fasting glucose. These associations increased when models were further adjusted for percent body fat: arsenic (OR 5.6, 95% C.I. 1.5, 21.2) and lead (OR 5.0, 95% C.I. 2.0, 12.7). Cadmium and mercury were also related with increased odds of elevated fasting glucose, but the associations were not statistically significant. Arsenic was significantly associated with increased odds of low HDL cholesterol both with (OR 8.0, 95% C.I. 1.8, 35.0) and without (OR 5.9, 95% C.I. 1.5, 23.1) adjustment for percent body fat.
While not consistent for all cardiometabolic disease markers, these results are suggestive of potentially important associations between metals exposure and cardiometabolic risk. Future studies will examine these associations in the larger cohort over time.
Arsenic; Cadmium; Cardiometabolic; Diabetes; Endocrine disruption; Lead; Mercury; Metals exposure; Obesity; Risk factor
Background. Certain hypertension subtypes have been shown to increase the risk for cardiovascular morbidity and mortality and may be related to specific underlying genetic determinants. Inappropriate characterization of subtypes of hypertension makes efforts at elucidating the genetic contributions to the etiology of hypertension largely vapid. We report the hypertension subtypes among patients with hypertension from South-Western Nigeria. Methods. A total of 1858 subjects comprising 76% female, hypertensive, aged 18 and above were recruited into the study from two centers in Ibadan, Nigeria. Hypertension was identified using JNCVII definition and was further grouped into four subtypes: controlled hypertension (CH), isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systolic-diastolic hypertension (SDH). Results. Systolic-diastolic hypertension was the most prevalent. Whereas SDH (77.6% versus 73.5%) and IDH (4.9% versus 4.7%) were more prevalent among females, ISH (10.1% versus 6.2%) was higher among males (P = 0.048). Female subjects were more obese (P < 0.0001) and SDH was prevalent among the obese group. Conclusion. Gender and obesity significantly influenced the distribution of the hypertension subtypes. Characterization of hypertension by subtypes in genetic association studies could lead to identification of previously unknown genetic variants involved in the etiology of hypertension. Large-scale studies among various ethnic groups may be needed to confirm these observations.
To evaluate evidence from published randomised controlled trials (RCTs) for the use of task-shifting strategies for cardiovascular disease (CVD) risk reduction in low-income and middle-income countries (LMICs).
Systematic review of RCTs that utilised a task-shifting strategy in the management of CVD in LMICs.
We searched the following databases for relevant RCTs: PubMed from the 1940s, EMBASE from 1974, Global Health from 1910, Ovid Health Star from 1966, Web of Knowledge from 1900, Scopus from 1823, CINAHL from 1937 and RCTs from ClinicalTrials.gov.
Eligibility criteria for selecting studies
We focused on RCTs published in English, but without publication year. We included RCTs in which the intervention used task shifting (non-physician healthcare workers involved in prescribing of medications, treatment and/or medical testing) and non-physician healthcare providers in the management of CV risk factors and diseases (hypertension, diabetes, hyperlipidaemia, stroke, coronary artery disease or heart failure), as well as RCTs that were conducted in LMICs. We excluded studies that are not RCTs.
Of the 2771 articles identified, only three met the predefined criteria. All three trials were conducted in practice-based settings among patients with hypertension (2 studies) and diabetes (1 study), with one study also incorporating home visits. The duration of the studies ranged from 3 to 12 months, and the task-shifting strategies included provision of medication prescriptions by nurses, community health workers and pharmacists and telephone follow-up posthospital discharge. Both hypertension studies reported a significant mean blood pressure reduction (2/1 mm Hg and 30/15 mm Hg), and the diabetes trial reported a reduction in the glycated haemoglobin levels of 1.87%.
There is a dearth of evidence on the implementation of task-shifting strategies to reduce the burden of CVD in LMICs. Effective task-shifting interventions targeted at reducing the global CVD epidemic in LMICs are urgently needed.
Task shifting; Cardiovascular diseases; Diabetes; Low-and middle-income countries; Systematic review
High blood pressure (BP) is the most common cardiovascular risk factor worldwide and a major contributor to heart disease and stroke. We previously discovered a BP-associated missense SNP (single nucleotide polymorphism)–rs2272996–in the gene encoding vanin-1, a glycosylphosphatidylinositol (GPI)-anchored membrane pantetheinase. In the present study, we first replicated the association of rs2272996 and BP traits with a total sample size of nearly 30,000 individuals from the Continental Origins and Genetic Epidemiology Network (COGENT) of African Americans (P = 0.01). This association was further validated using patient plasma samples; we observed that the N131S mutation is associated with significantly lower plasma vanin-1 protein levels. We observed that the N131S vanin-1 is subjected to rapid endoplasmic reticulum-associated degradation (ERAD) as the underlying mechanism for its reduction. Using HEK293 cells stably expressing vanin-1 variants, we showed that N131S vanin-1 was degraded significantly faster than wild type (WT) vanin-1. Consequently, there were only minimal quantities of variant vanin-1 present on the plasma membrane and greatly reduced pantetheinase activity. Application of MG-132, a proteasome inhibitor, resulted in accumulation of ubiquitinated variant protein. A further experiment demonstrated that atenolol and diltiazem, two current drugs for treating hypertension, reduce the vanin-1 protein level. Our study provides strong biological evidence for the association of the identified SNP with BP and suggests that vanin-1 misfolding and degradation are the underlying molecular mechanism.
Hypertension (HTN) or high blood pressure (BP) is common worldwide and a major risk factor for cardiovascular disease and all-cause mortality. Identification of genetic variants of consequence for HTN serves as the molecular basis for its treatment. Using admixture mapping analysis of the Family Blood Pressure Program data, we recently identified that the VNN1 gene (encoding the protein vanin-1), in particular SNP rs2272996 (N131S), was associated with BP in both African Americans and Mexican Americans. Vanin-1 was reported to act as an oxidative stress sensor using its pantetheinase enzyme activity. Because a linkage between oxidative stress and HTN has been hypothesized for many years, vanin-1's pantetheinase activity offers a physiologic rationale for BP regulation. Here, we first replicated the association of rs2272996 with BP in the Continental Origins and Genetic Epidemiology Network (COGENT), which included nearly 30,000 African Americans. We further demonstrated that the N131S mutation in vanin-1 leads to its rapid degradation in cells, resulting in loss of function on the plasma membrane. The loss of function of vanin-1 is associated with reduced BP. Therefore, our results indicate that vanin-1 is a new candidate to be manipulated to ameliorate HTN.
This difference in how populations living in low-, middle or upper-income countries accumulate daily PA, i.e. patterns and intensity, is an important part in addressing the global PA movement. We sought to characterize objective PA in 2,500 participants spanning the epidemiologic transition. The Modeling the Epidemiologic Transition Study (METS) is a longitudinal study, in 5 countries. METS seeks to define the association between physical activity (PA), obesity and CVD risk in populations of African origin: Ghana (GH), South Africa (SA), Seychelles (SEY), Jamaica (JA) and the US (suburban Chicago).
Baseline measurements of objective PA, SES, anthropometrics and body composition, were completed on 2,500 men and women, aged 25–45 years. Moderate and vigorous PA (MVPA, min/d) on week and weekend days was explored ecologically, by adiposity status and manual labor.
Among the men, obesity prevalence reflected the level of economic transition and was lowest in GH (1.7%) and SA (4.8%) and highest in the US (41%). SA (55%) and US (65%) women had the highest levels of obesity, compared to only 16% in GH. More men and women in developing countries engaged in manual labor and this was reflected by an almost doubling of measured MPVA among the men in GH (45 min/d) and SA (47 min/d) compared to only 28 min/d in the US. Women in GH (25 min/d), SA (21 min/d), JA (20 min/d) and SEY (20 min/d) accumulated significantly more MPVA than women in the US (14 min/d), yet this difference was not reflected by differences in BMI between SA, JA, SEY and US. Moderate PA constituted the bulk of the PA, with no study populations except SA men accumulating > 5 min/d of vigorous PA. Among the women, no sites accumulated >2 min/d of vigorous PA. Overweight/obese men were 22% less likely to engage in manual occupations.
While there is some association for PA with obesity, this relationship is inconsistent across the epidemiologic transition and suggests that PA policy recommendations should be tailored for each environment.
Physical activity patterns; Manual labor; Epidemiologic transition
The prevalence of pre-diabetes (PD) among US adults has increased substantially over the past two decades. By current estimates, over 34% of US adults fall in the PD category, 84% of whom meet the American Diabetes Association’s criteria for impaired fasting glucose (IFG). Low physical activity (PA) and/or sedentary behavior are key drivers of hyperglycemia. We examined the relationship between PD and objectively measured PA in NHANES 2003–2006 of 20,470 individuals, including 7,501 individuals between 20 and 65 yrs.We excluded all participants without IFG measures or adequate accelerometry data (final N = 1,317). Participants were identified as PD if FPG was 100–125 mg/dL (5.6–6.9 mmol/L). Moderate and vigorous PA in minutes/day individuals were summed to create the exposure variable “moderate-vigorous PA” (MVPA). The analysis sample included 884 normoglycemic persons and 433 with PD. There were significantly fewer PD subjects in the middle (30.3%) and highest (24.6%) tertiles of PA compared to the lowest tertile (35.5%). After adjusting for BMI, participants were 0.77 times as likely to be PD if they were in the highest tertile compared to the lowest PA tertile (p < 0.001). However, these results were no longer significant when age and BMI were held constant. Univariate analysis revealed that physical activity was associated with decreased fasting glucose of 0.5 mg/dL per minute of MVPA, but multivariate analysis adjusting for age and BMI was not significant. Overall, our data suggest a negative association between measures of PA and the prevalence of PD in middle-aged US adults independent of adiposity, but with significant confounding influence from measures of BMI and age.
Pre-diabetes; Physical activity; NHANES
Patients with sickle cell disease in the USA have been noted to have lower levels of vitamin D – measured as 25-hydroxyvitamin D (25(OH)D) – compared to controls. Average serum 25(OH)D levels are also substantially lower in African Americans than whites, while population distributions of 25(OH)D among Jamaicans of African descent and West Africans are the same as among USA whites. The purpose of this study was to examine whether adult patients with sickle cell disease living in tropical regions had reduced 25(OH)D relative to the general population.
We analyzed serum 25(OH)D in stored samples collected from studies in Jamaica and West Africa of adult patients with sickle cell disease and adult population controls.
In samples of 20 Jamaicans and 50 West Africans with sickle cell disease mean values of 25(OH)D were 37% and 39% lower than controls, respectively. Metabolic abnormalities in the absorption and conversion pathways are possible causes for the consistent relative deficiency of 25(OH)D in sickle cell disease.
Low 25(OH)D levels in tropical Africa where the burden of sickle cell disease is highest, deserve further investigation, and a randomized trial is warranted to address efficacy of supplementation.
Sickle cell disease; Sickle cell anemia; Vitamin D; 25-hydroxyvitamin D; Adult patients; Tropical Africa; Jamaica; West Africa
Sequences up to several megabases in length have been found to be present in individual genomes but absent in the human reference genome. These sequences may be common in populations, and their absence in the reference genome may indicate rare variants in the genomes of individuals who served as donors for the human genome project. As the reference genome is used in probe design for microarray technology and mapping short reads in next generation sequencing (NGS), this missing sequence could be a source of bias in functional genomic studies and variant analysis. One End Anchor (OEA) and/or orphan reads from paired-end sequencing have been used to identify novel sequences that are absent in reference genome. However, there is no study to investigate the distribution, evolution and functionality of those sequences in human populations.
To systematically identify and study the missing common sequences (micSeqs), we extended the previous method by pooling OEA reads from large number of individuals and applying strict filtering methods to remove false sequences. The pipeline was applied to data from phase 1 of the 1000 Genomes Project. We identified 309 micSeqs that are present in at least 1% of the human population, but absent in the reference genome. We confirmed 76% of these 309 micSeqs by comparison to other primate genomes, individual human genomes, and gene expression data. Furthermore, we randomly selected fifteen micSeqs and confirmed their presence using PCR validation in 38 additional individuals. Functional analysis using published RNA-seq and ChIP-seq data showed that eleven micSeqs are highly expressed in human brain and three micSeqs contain transcription factor (TF) binding regions, suggesting they are functional elements. In addition, the identified micSeqs are absent in non-primates and show dynamic acquisition during primate evolution culminating with most micSeqs being present in Africans, suggesting some micSeqs may be important sources of human diversity.
76% of micSeqs were confirmed by a comparative genomics approach. Fourteen micSeqs are expressed in human brain or contain TF binding regions. Some micSeqs are primate-specific, conserved and may play a role in the evolution of primates.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-685) contains supplementary material, which is available to authorized users.
Missing common sequence; De novo assembling; Next generation sequencing; Expression in brain; Transcription factor binding; Genome evolution
African Americans have substantially lower levels of circulating 25(OH)D than whites. We compared population-based samples of 25(OH)D in women of African descent from Nigeria and metropolitan Chicago.
100 Women of Yoruba ethnicity from southwest Nigeria and 94 African American women from metropolitan Chicago were recruited and compared using a standardized survey protocol and the same laboratory assay for 25(OH)D.
Mean 25(OH)D levels were 64 nmol/L among the Nigerians and 29 nmol/L among the African Americans. Only 10% of the values were shared in common between the groups, and 76% of the Nigerians were above the currently defined threshold for adequate circulating 25(OH)D compared to 5% of the African Americans. Modest associations were seen between 25(OH)D and measures of obesity, although adjustment for these traits did not materially affect the group differences.
These data support the presumption that skin color is an adaptive trait which has evolved in part to regulate 25(OH)D. It remains undetermined, however, whether lower values observed in African Americans have negative health consequences.
vitamin D; African American; Nigerian; obesity
Random number generation (RNG) is a complex cognitive task for human subjects, requiring deliberative control to avoid production of habitual, stereotyped sequences. Under various manipulations (e.g., speeded responding, transcranial magnetic stimulation, or neurological damage) the performance of human subjects deteriorates, as reflected in a number of qualitatively distinct, dissociable biases. For example, the intrusion of stereotyped behavior (e.g., counting) increases at faster rates of generation. Theoretical accounts of the task postulate that it requires the integrated operation of multiple, computationally heterogeneous cognitive control (“executive”) processes. We present a computational model of RNG, within the framework of a novel, neuropsychologically-inspired cognitive architecture, ESPro. Manipulating the rate of sequence generation in the model reproduced a number of key effects observed in empirical studies, including increasing sequence stereotypy at faster rates. Within the model, this was due to time limitations on the interaction of supervisory control processes, namely, task setting, proposal of responses, monitoring, and response inhibition. The model thus supports the fractionation of executive function into multiple, computationally heterogeneous processes.
random number generation; executive function; cognitive control; cognitive architecture; computational model; supervisory system
Countries in sub-Saharan Africa (SSA) are experiencing an epidemic of cardiovascular disease (CVD) propelled by rapidly increasing rates of hypertension. Barriers to hypertension control in SSA include poor access to care and high out-of-pocket costs. Although SSA bears 24% of the global disease burden, it has only 3% of the global health workforce. Given such limited resources, cost-effective strategies, such as task shifting, are needed to mitigate the rising CVD epidemic in SSA. Ghana, a country in SSA with an established community health worker program integrated within a national health insurance scheme provides an ideal platform to evaluate implementation of the World Health Organization (WHO) task-shifting strategy. This study will evaluate the comparative effectiveness of the implementation of the WHO Package targeted at CV risk assessment versus provision of health insurance coverage, on blood pressure (BP) reduction.
Using a cluster randomized design, 32 community health centers (CHCs) and district hospitals in Ghana will be randomized to either the intervention group (16 CHCs) or the control group (16 CHCs). A total of 640 patients with uncomplicated hypertension (BP 140–179/90–99 mm Hg and absence of target organ damage) will be enrolled in this study (20 patients per CHC). The intervention consists of WHO Package of CV risk assessment, patient education, initiation and titration of antihypertensive medications, behavioral counseling on lifestyle behaviors, and medication adherence every three months for 12 months. The primary outcome is the mean change in systolic BP from baseline to 12 months. The secondary outcomes are rates of BP control at 12 months; levels of physical activity, percent change in weight, and dietary intake of fruits and vegetables at 12 months; and sustainability of intervention effects at 24 months. All outcomes will be assessed at baseline, six months and 12 months. Trained community health nurses will deliver the intervention as part of Ghana’s community-based health planning and services (CHPS) program.
Findings from this study will provide policy makers and other stakeholders needed information to recommend scalable and cost-effective policy with respect to comprehensive CV risk reduction and hypertension control in resource-poor settings.
Hypertension; Cluster randomized controlled trial; Task shifting; Blood pressure control; Community health centers; Community health nurses; Ghana
In West Africa, hypertension, once rare, has now emerged as a critical health concern and the trajectory is upward and factors are complex. The true magnitude of hypertension in some West African countries, including in-depth knowledge of underlying risk factors is not completely understood. There is also a paucity of research on adequate systems-level approaches designed to mitigate the growing burden of hypertension in the region.
In this review, we thematically synthesize available literature pertaining to the prevalence of hypertension in West Africa and discuss factors that influence its diagnosis, treatment and control. We aimed to address the social and structural determinants influencing hypertension in the sub-region including the effects of urbanization, health infrastructure and healthcare workforce.
The prevalence of hypertension in West Africa has increased over the past decade and is rising rapidly with an urban-rural gradient that places higher hypertension prevalence on urban settings compared to rural settings. Overall levels of awareness of one’s hypertension status remain consistently low in West African. Structural and economic determinants related to conditions of poverty such as insufficient finances have a direct impact on adherence to prescribed antihypertensive medications. Urbanization contributes to the increasing incidence of hypertension in the sub-region and available evidence indicates that inadequate health infrastructure may act as a barrier to optimal hypertension control in West Africa.
Given that optimal hypertension control in West Africa depends on multiple factors that go beyond simply modifying the behaviors of the individuals alone, we conclude by discussing the potential role systems-thinking approaches can play to achieve optimal control in the sub-region. In the context of recent advances in hypertension management including new therapeutic options and innovative solutions to expand health workforce so as to meet the high demand for healthcare, the success of these strategies will rely on a new understanding of the complexity of human behaviors and interactions most aptly framed from a systems-thinking perspective.
Despite rising levels of obesity in England, little is known about slimming club and weight loss drug (medication) use or users. In order to inform future commissioning, we report the prevalence of various weight management strategies and examine the associations between slimming club and medication use and age, gender, deprivation and body mass index.
A population based cross-sectional survey of 26,113 adults was conducted in South Yorkshire using a self-completed health questionnaire. Participants were asked whether they had ever used the following interventions to manage their weight: increasing exercise, healthy eating, controlling portion size, slimming club, over the counter weight loss medication, or meal replacements. Factors associated with slimming club and weight-loss medication use were explored using logistic regression.
Over half of the sample was either overweight (36.6%) or obese (19.6%). Obesity was more common in the most deprived areas compared to the least deprived (26.3% vs. 12.0%). Healthy eating (49.0%), controlling portion size (43.4%), and increasing exercise (43.0%) were the most commonly reported weight management strategies. Less common strategies were attending a slimming club (17.2%), meal replacements (3.4%) and weight-loss medication (3.2%). Adjusting for BMI, age, deprivation and long standing health conditions, women were significantly more likely to report ever using a slimming club (adjusted OR = 18.63, 95% CI = 16.52–21.00) and more likely to report ever using over the counter weight-loss medications (AOR = 3.73, 95% CI = 3.10-4.48), while respondents from the most deprived areas were less likely to report using slimming clubs (AOR = 0.60, 95% CI = 0.53-0.68), and more likely to reporting using weight loss medications (AOR =1.38, 95% CI = 1.05-1.82).
A large proportion of individuals report having used weight management strategies. Slimming clubs and over-the-counter weight loss medication account for a smaller proportion of the overall uptake. Those from less deprived areas were more likely to use slimming clubs while those from more deprived areas were more likely to use weight-loss medications. Future NHS and Local Authority commissioning of weight management services must be aware of this varying social gradient in weight management strategies.
Obesity; Weight management strategy; Population; Survey; Cohort; Slimming clubs; Weight loss medication
Low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, and total cholesterol are heritable, modifiable, risk factors for coronary artery disease. To identify new loci and refine known loci influencing these lipids, we examined 188,578 individuals using genome-wide and custom genotyping arrays. We identify and annotate 157 loci associated with lipid levels at P < 5×10−8, including 62 loci not previously associated with lipid levels in humans. Using dense genotyping in individuals of European, East Asian, South Asian, and African ancestry, we narrow association signals in 12 loci. We find that loci associated with blood lipids are often associated with cardiovascular and metabolic traits including coronary artery disease, type 2 diabetes, blood pressure, waist-hip ratio, and body mass index. Our results illustrate the value of genetic data from individuals of diverse ancestries and provide insights into biological mechanisms regulating blood lipids to guide future genetic, biological, and therapeutic research.
Triglycerides are transported in plasma by specific triglyceride-rich lipoproteins; in epidemiologic studies, increased triglyceride levels correlate with higher risk for coronary artery disease (CAD). However, it is unclear whether this association reflects causal processes. We used 185 common variants recently mapped for plasma lipids (P<5×10−8 for each) to examine the role of triglycerides on risk for CAD. First, we highlight loci associated with both low-density lipoprotein cholesterol (LDL-C) and triglycerides, and show that the direction and magnitude of both are factors in determining CAD risk. Second, we consider loci with only a strong magnitude of association with triglycerides and show that these loci are also associated with CAD. Finally, in a model accounting for effects on LDL-C and/or high-density lipoprotein cholesterol, a polymorphism's strength of effect on triglycerides is correlated with the magnitude of its effect on CAD risk. These results suggest that triglyceride-rich lipoproteins causally influence risk for CAD.
Examination of patterns and intensity of physical activity (PA) across cultures where obesity prevalence varies widely provides insight into one aspect of the ongoing epidemiologic transition. The primary hypothesis being addressed is whether low levels of PA are associated with excess weight and adiposity.
We recruited young adults from five countries (500 per country, 2500 total, ages 25–45 years), spanning the range of obesity prevalence. Men and women were recruited from a suburb of Chicago, Illinois, USA; urban Jamaica; rural Ghana; peri-urban South Africa; and the Seychelles. PA was measured using accelerometry and expressed as minutes per day of moderate-to-vigorous activity or sedentary behavior.
Obesity (BMI ≥ 30) prevalence ranged from 1.4% (Ghanaian men) to 63.8% (US women). South African men were the most active, followed by Ghanaian men. Relatively small differences were observed across sites among women; however, women in Ghana accumulated the most activity. Within site-gender sub-groups, the correlation of activity with BMI and other measures of adiposity was inconsistent; the combined correlation across sites was -0.17 for men and -0.11 for women. In the ecological analysis time spent in moderate-to-vigorous activity was inversely associated with BMI (r = -0.71).
These analyses suggest that persons with greater adiposity tend to engage in less PA, although the associations are weak and the direction of causality cannot be inferred because measurements are cross-sectional. Longitudinal data will be required to elucidate direction of association.
Physical activity; Obesity; Epidemiologic transition
Genetic variation at loci influencing adult levels of HbF have been shown to modify the clinical course of sickle cell disease (SCD). Data on this important aspect of SCD have not yet been reported from West Africa. We investigated the relationship between HbF levels and the relevant genetic loci in 610 patients with SCD (98% HbSS homozygotes) from Cameroon, and compared the results to a well-characterized African-American cohort.
Methods and Findings
Socio-demographic and clinical features were collected and medical records reviewed. Only patients >5 years old, who had not received a blood transfusion or treatment with hydroxyurea were included. Hemoglobin electrophoresis and a full blood count were conducted upon arrival at the hospital. RFLP-PCR was used to describe the HBB gene haplotypes. SNaPshot PCR, Capillary electrophoresis and cycle sequencing were used for the genotyping of 10 selected SNPs. Genetic analysis was performed with PLINK software and statistical models in the statistical package R. Allele frequencies of relevant variants at BCL11A were similar to those detected in African Americans; although the relationships with Hb F were significant (p <.001), they explained substantially less of the variance in HbF than was observed among African Americans (∼ 2% vs 10%). SNPs in HBS1L-MYB region (HMIP) likewise had a significant impact on HbF, however, we did not find an association between HbF and the variations in HBB cluster and OR51B5/6 locus on chromosome 11p, due in part to the virtual absence of the Senegal and Indian Arab haplotypes. We also found evidence that selected SNPs in HBS1L-MYB region (HMIP) and BCL11A affect both other hematological indices and rates of hospitalization.
This study has confirmed the associations of SNPs in BCL11A and HBS1L-MYB and fetal haemoglobin in Cameroonian SCA patients; hematological indices and hospitalization rates were also associated with specific allelic variants.
Hypertension (HTN) affects ~30% of adults in industrialized countries and is the major risk factor for cardiovascular disease.
We sought to study the genetic effect of coding and conserved non-coding variants in syndromic HTN genes on systolic (SBP) and diastolic (DBP) blood pressure to assess their overall impact on essential hypertension (EH).
Methods and Results
We resequenced 11 genes (AGT, CYP11B1, CYP17A1, HSD11B2, NR3C1, NR3C2, SCNN1A, SCNN1B, SCNN1G, WNK1 and WNK4) in 560 European (EA) and African (AA) ancestry GenNet participants with extreme SBP. We investigated genetic associations of 2,535 variants with BP in 19,997 EAs and 6,069 AAs in three types of analyses. First, we studied the combined effects of all variants in GenNet. Second, we studied 1000 Genomes imputed polymorphic variants in 9,747 EA and 3,207 AA ARIC subjects. Lastly, we genotyped 37 missense and common noncoding variants in 6,591 EAs and 6,521 individuals (3,659 EA/2,862 AA) from the CLUE and FBPP studies. None of the variants individually reached significant false-discovery rates (FDR≤0.05) for SBP and DBP. However, upon pooling all coding and non-coding variants we identified at least 5 loci (AGT, CYP11B1, NR3C2, SCNN1G and WNK1), with higher association at evolutionary conserved sites.
Both rare and common variants at these genes affect BP in the general population with modest effects sizes (<0.05 standard deviation units) and much larger sample sizes are required to assess the impact of individual genes. Collectively, conserved noncoding variants affect BP to a greater extent than missense mutations.
essential hypertension; blood pressure; population genetics; sequencing; genotype
Research in industrialized countries has demonstrated that a key factor limiting the control of hypertension is poor patient adherence and that the most successful interventions for long-term adherence employ multiple strategies. Very little data exist on this question in low-income countries, where medication-taking behavior may be less well developed. We conducted a treatment adherence trial of 544 subjects (mean age ~63 years, mean BP ~168/92 mmHg) with previously untreated hypertension in urban and rural Nigeria. Eligible participants were randomized to one of two arms: clinic management only, or clinic management + home visits. Both interventions included three elements: a community based, nurse-led treatment program with physician backup; facilitation of clinic visits and health education; and the use of diuretics plus a beta blocker as needed. After initial diagnosis, the management protocol was implemented by a nurse with physician backup. Participants were evaluated monthly for 6 months. Medication adherence was assessed with pill count and urine testing. Dropout rates, by treatment group, ranged from 12% to 28%. Among participants who completed the 6 month trial, overall adherence was high (~77% of participants took > 98% of prescribed pills). Adherence did not differ by treatment arm, but was better at the rural than the urban site and among those with higher baseline BP. Hypertension control (BP < 140/90 mmHg) was achieved in ~66% of participants at 6 months. This community-based intervention confirms relatively modest default rates compared to industrialized societies, and suggests that medication adherence can be high in developing world settings in clinic attenders.
anti-hypertensive; adherence; compliance trial
Genome-wide association studies (GWAS) have identified 36 loci associated with body mass index (BMI), predominantly in populations of European ancestry. We conducted a meta-analysis to examine the association of >3.2 million SNPs with BMI in 39,144 men and women of African ancestry, and followed up the most significant associations in an additional 32,268 individuals of African ancestry. We identified one novel locus at 5q33 (GALNT10, rs7708584, p=3.4×10−11) and another at 7p15 when combined with data from the Giant consortium (MIR148A/NFE2L3, rs10261878, p=1.2×10−10). We also found suggestive evidence of an association at a third locus at 6q16 in the African ancestry sample (KLHL32, rs974417, p=6.9×10−8). Thirty-two of the 36 previously established BMI variants displayed directionally consistent effect estimates in our GWAS (binomial p=9.7×10−7), of which five reached genome-wide significance. These findings provide strong support for shared BMI loci across populations as well as for the utility of studying ancestrally diverse populations.
The objective was to investigate the association between BMI and single nucleotide polymorphisms previously identified of obesity-related genes in two Spanish populations. Forty SNPs in 23 obesity-related genes were evaluated in a rural population characterized by a high prevalence of obesity (869 subjects, mean age 46 yr, 62% women, 36% obese) and in an urban population (1425 subjects, mean age 54 yr, 50% women, 19% obese). Genotyping was assessed by using SNPlex and PLINK for the association analysis.
Polymorphisms of the FTO were significantly associated with BMI, in the rural population (beta 0.87, p-value <0.001). None of the other SNPs showed significant association after Bonferroni correction in the two populations or in the pooled analysis. A weighted genetic risk score (wGRS) was constructed using the risk alleles of the Tag-SNPs with a positive Beta parameter in both populations. From the first to the fifth quintile of the score, the BMI increased 0.45 kg/m2 in Hortega and 2.0 kg/m2 in Pizarra. Overall, the obesity predictive value was low (less than 1%).
The risk associated with polymorphisms is low and the overall effect on BMI or obesity prediction is minimal. A weighted genetic risk score based on genes mainly acting through central nervous system mechanisms was associated with BMI but it yields minimal clinical prediction for the obesity risk in the general population.
Obesity; Genetics; FTO gene; Genetic score
Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group’s mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered.
Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria.
The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative “Plan B” technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, “cannot intubate, cannot oxygenate” situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.
Appropriate planning is crucial to avoid morbidity and mortality when difficulty is anticipated with airway management. Many guidelines developed by national societies have focused on management of difficulty encountered in the unconscious patient; however, little guidance appears in the literature on how best to approach the patient with an anticipated difficult airway.
To review this and other subjects, the Canadian Airway Focus Group (CAFG) was re-formed. With representation from anesthesiology, emergency medicine, and critical care, CAFG members were assigned topics for review. As literature reviews were completed, results were presented and discussed during teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made, and levels of evidence were assigned.
Previously published predictors of difficult direct laryngoscopy are widely known. More recent studies report predictors of difficult face mask ventilation, video laryngoscopy, use of a supraglottic device, and cricothyrotomy. All are important facets of a complete airway evaluation and must be considered when difficulty is anticipated with airway management. Many studies now document the increasing patient morbidity that occurs with multiple attempts at tracheal intubation. Therefore, when difficulty is anticipated, tracheal intubation after induction of general anesthesia should be considered only when success with the chosen device(s) can be predicted in a maximum of three attempts. Concomitant predicted difficulty using oxygenation by face mask or supraglottic device ventilation as a fallback makes an awake approach advisable. Contextual issues, such as patient cooperation, availability of additional skilled help, and the clinician’s experience, must also be considered in deciding the appropriate strategy.
With an appropriate airway evaluation and consideration of relevant contextual issues, a rational decision can be made on whether an awake approach to tracheal intubation will maximize patient safety or if airway management can safely proceed after induction of general anesthesia. With predicted difficulty, close attention should be paid to details of implementing the chosen approach. This should include having a plan in case of the failure of tracheal intubation or patient oxygenation.
Over-the-counter (OTC) pharmacy medicines are considered relatively safe in contrast to prescribed and illicit substances, but their abuse and addiction potential is increasingly recognised. Those affected represent a hard to reach group, with little known about their experiences. Study objectives were to describe the experiences and views of those self-reporting OTC medicine abuse, and why medicines were taken, how they were obtained and associated treatment and support sought.
Qualitative study using in-depth mainly telephone interviews.
A purposive sample of 25 adults, aged 20–60s, 13 women.
UK, via two internet support groups.
Individuals considered themselves ‘addicted’, but socially and economically active and different from illicit substance misusers. They blamed themselves for losing control over their medicine use, which usually began for genuine medical reasons and not experimentation and was often linked to the cessation of, or ongoing, medical prescribing. Codeine, in compound analgesics, was the main medicine implicated with three distinct dose ranges emerging with decongestant and sedative antihistamine abuse also being reported. Subsequent use was for the ‘buzz’ or similar effects of the opiate, which was obtained unproblematically by having lists of pharmacies to visit and occasionally using internet suppliers. Perceived withdrawal symptoms were described for all three dose ranges, and work and health problems were reported with higher doses. Mixed views about different treatment and support options emerged with standard drug treatment services being considered inappropriate for OTC medicines and concerns that this ‘hidden addiction’ was recorded in medical notes. Most supported the continued availability of OTC medicines with appropriate addiction warnings.
Greater awareness of the addiction potential of OTC medicines is needed for the public, pharmacists and medical prescribers, along with appropriate communication about, and reviews of, treatment and support options, for this distinct group.
Qualitative Research; Primary Care
Decision-making behavior is studied in many very different fields, from medicine and economics to psychology and neuroscience, with major contributions from mathematics and statistics, computer science, AI, and other technical disciplines. However the conceptualization of what decision-making is and methods for studying it vary greatly and this has resulted in fragmentation of the field. A theory that can accommodate various perspectives may facilitate interdisciplinary working. We present such a theory in which decision-making is articulated as a set of canonical functions that are sufficiently general to accommodate diverse viewpoints, yet sufficiently precise that they can be instantiated in different ways for specific theoretical or practical purposes. The canons cover the whole decision cycle, from the framing of a decision based on the goals, beliefs, and background knowledge of the decision-maker to the formulation of decision options, establishing preferences over them, and making commitments. Commitments can lead to the initiation of new decisions and any step in the cycle can incorporate reasoning about previous decisions and the rationales for them, and lead to revising or abandoning existing commitments. The theory situates decision-making with respect to other high-level cognitive capabilities like problem solving, planning, and collaborative decision-making. The canonical approach is assessed in three domains: cognitive and neuropsychology, artificial intelligence, and decision engineering.
decision-making; autonomous agents; clinical decision-making; unified theories of cognition; cognitive systems