A biomarker feasibility study in the South East Asia Community Observatory health and demographic surveillance system.

BACKGROUND: Integration of biomarker data with information on health and lifestyle provides a powerful tool to enhance the scientific value of health research. Existing health and demographic surveillance systems (HDSSs) present an opportunity to create novel biodata resources for this purpose, but data and biological sample collection often presents challenges. We outline some of the challenges in developing these resources and present the outcomes of a biomarker feasibility study embedded within the South East Asia Community Observatory (SEACO) HDSS. METHODS: We assessed study-related records to determine the pace of data collection, response from potential participants, and feedback following data and sample collection. Overall and stratified measures of data and sample availability were summarised. Crude prevalence of key risk factors was examined. RESULTS: Approximately half (49.5%) of invited individuals consented to participate in this study, for a final sample size of 203 (161 adults and 42 children). Women were more likely to consent to participate compared with men, whereas children, young adults and individuals of Malay ethnicity were less likely to consent compared with older individuals or those of any other ethnicity. At least one biological sample (blood from all participants - finger-prick and venous [for serum, plasma and whole blood samples], hair or urine for adults only) was successfully collected from all participants, with blood test data available from over 90% of individuals. Among adults, urine samples were most commonly collected (97.5%), followed by any blood samples (91.9%) and hair samples (83.2%). Cardiometabolic risk factor burden was high (prevalence of elevated HbA1c among adults: 23.8%; of elevated triglycerides among adults: 38.1%; of elevated total cholesterol among children: 19.5%). CONCLUSIONS: In this study, we show that it is feasible to create biodata resources using existing HDSS frameworks, and identify a potentially high burden of cardiometabolic risk factors that requires further evaluation in this population.

Antimicrobial resistance in human populations: challenges and opportunities.

Antimicrobial resistance (AMR) is a global public health threat. Emergence of AMR occurs naturally, but can also be selected for by antimicrobial exposure in clinical and veterinary medicine. Despite growing worldwide attention to AMR, there are substantial limitations in our understanding of the burden, distribution and determinants of AMR at the population level. We highlight the importance of population-based approaches to assess the association between antimicrobial use and AMR in humans and animals. Such approaches are needed to improve our understanding of the development and spread of AMR in order to inform strategies for the prevention, detection and management of AMR, and to support the sustainable use of antimicrobials in healthcare.

Deriving an optimal threshold of waist circumference for detecting cardiometabolic risk in sub-Saharan Africa.

BACKGROUND: Waist circumference (WC) thresholds derived from western populations continue to be used in sub-Saharan Africa (SSA) despite increasing evidence of ethnic variation in the association between adiposity and cardiometabolic disease and availability of data from African populations. We aimed to derive a SSA-specific optimal WC cut-point for identifying individuals at increased cardiometabolic risk. METHODS: We used individual level cross-sectional data on 24 181 participants aged ⩾15 years from 17 studies conducted between 1990 and 2014 in eight countries in SSA. Receiver operating characteristic curves were used to derive optimal WC cut-points for detecting the presence of at least two components of metabolic syndrome (MS), excluding WC. RESULTS: The optimal WC cut-point was 81.2 cm (95% CI 78.5-83.8 cm) and 81.0 cm (95% CI 79.2-82.8 cm) for men and women, respectively, with comparable accuracy in men and women. Sensitivity was higher in women (64%, 95% CI 63-65) than in men (53%, 95% CI 51-55), and increased with the prevalence of obesity. Having WC above the derived cut-point was associated with a twofold probability of having at least two components of MS (age-adjusted odds ratio 2.6, 95% CI 2.4-2.9, for men and 2.2, 95% CI 2.0-2.3, for women). CONCLUSION: The optimal WC cut-point for identifying men at increased cardiometabolic risk is lower (⩾81.2 cm) than current guidelines (⩾94.0 cm) recommend, and similar to that in women in SSA. Prospective studies are needed to confirm these cut-points based on cardiometabolic outcomes.International Journal of Obesity advance online publication, 31 October 2017; doi:10.1038/ijo.2017.240.

Whole-genome association study of antibody response to Epstein-Barr virus in an African population: a pilot.

Epstein Barr virus (EBV) infects 95% of the global population and is associated with up to 2% of cancers globally. Immunoglobulin G (IgG) antibody levels to EBV have been shown to be heritable and associated with developing malignancies. We, therefore, performed a pilot genome-wide association analysis of anti-EBV IgG traits in an African population, using a combined approach including array genotyping, whole-genome sequencing and imputation to a panel with African sequence data. In 1562 Ugandans, we identify a variant in human leukocyte antigen (HLA)-DQA1, rs9272371 (p = 2.6 × 10-17) associated with anti-EBV nuclear antigen-1 responses. Trans-ancestry meta-analysis and fine-mapping with European-ancestry individuals suggest the presence of distinct HLA class II variants driving associations in Uganda. In addition, we identify four putative, novel, very rare African-specific loci with preliminary evidence for association with anti-viral capsid antigen IgG responses which will require replication for validation. These findings reinforce the need for the expansion of such studies in African populations with relevant datasets to capture genetic diversity.

Erratum: Antimicrobial resistance in human populations: challenges and opportunities - ERRATUM.

[This corrects the article DOI: 10.1017/gheg.2017.4.].

The need for an integrated approach for chronic disease research and care in Africa.

With the changing distribution of infectious diseases, and an increase in the burden of non-communicable diseases, low- and middle-income countries, including those in Africa, will need to expand their health care capacities to effectively respond to these epidemiological transitions. The interrelated risk factors for chronic infectious and non-communicable diseases and the need for long-term disease management, argue for combined strategies to understand their underlying causes and to design strategies for effective prevention and long-term care. Through multidisciplinary research and implementation partnerships, we advocate an integrated approach for research and healthcare for chronic diseases in Africa.

Study profile: the Durban Diabetes Study (DDS): a platform for chronic disease research.

The Durban Diabetes Study (DDS) is a population-based cross-sectional survey of an urban black population in the eThekwini Municipality (city of Durban) in South Africa. The survey combines health, lifestyle and socioeconomic questionnaire data with standardised biophysical measurements, biomarkers for non-communicable and infectious diseases, and genetic data. Data collection for the study is currently underway and the target sample size is 10 000 participants. The DDS has an established infrastructure for survey fieldwork, data collection and management, sample processing and storage, managed data sharing and consent for re-approaching participants, which can be utilised for further research studies. As such, the DDS represents a rich platform for investigating the distribution, interrelation and aetiology of chronic diseases and their risk factors, which is critical for developing health care policies for disease management and prevention. For data access enquiries please contact the African Partnership for Chronic Disease Research (APCDR) at data@apcdr.org or the corresponding author.

H3Africa multi-centre study of the prevalence and environmental and genetic determinants of type 2 diabetes in sub-Saharan Africa: study protocol.

The burden and aetiology of type 2 diabetes (T2D) and its microvascular complications may be influenced by varying behavioural and lifestyle environments as well as by genetic susceptibility. These aspects of the epidemiology of T2D have not been reliably clarified in sub-Saharan Africa (SSA), highlighting the need for context-specific epidemiological studies with the statistical resolution to inform potential preventative and therapeutic strategies. Therefore, as part of the Human Heredity and Health in Africa (H3Africa) initiative, we designed a multi-site study comprising case collections and population-based surveys at 11 sites in eight countries across SSA. The goal is to recruit up to 6000 T2D participants and 6000 control participants. We will collect questionnaire data, biophysical measurements and biological samples for chronic disease traits, risk factors and genetic data on all study participants. Through integrating epidemiological and genomic techniques, the study provides a framework for assessing the burden, spectrum and environmental and genetic risk factors for T2D and its complications across SSA. With established mechanisms for fieldwork, data and sample collection and management, data-sharing and consent for re-approaching participants, the study will be a resource for future research studies, including longitudinal studies, prospective case ascertainment of incident disease and interventional studies.

The ADRB3 Trp64Arg variant and BMI: a meta-analysis of 44 833 individuals.

BACKGROUND: The beta-3 adrenergic receptor gene (ADRB3) is part of the adrenergic system, which is known to play a key role in energy metabolism. The association between the Trp64Arg variant in the ADRB3 and body mass index (BMI) has been widely examined, but previous studies have been small and results have been inconsistent. METHODS: We assessed the association between the ADRB3 Trp64Arg variant and BMI in a large UK population-based cohort of 4854 middle-aged men and women. We also performed a meta-analysis of 97 studies, involving 44 833 individuals, to place our findings in context. RESULTS: Although we found no significant difference in BMI (0.20 kg/m(2), P=0.40) between the Trp64Trp homozygotes and Arg64 allele carriers in our UK population-based cohort, the meta-analysis showed significant association between the Arg64Trp variant and BMI, with Arg64-allele carriers having a 0.24 kg/m(2) (P=0.0002) higher BMI compared with noncarriers. However, we also found substantial heterogeneity among the studies (P=2.2 x 10(-14)). The difference in East Asians (0.31 kg/m(2), P=0.001) was 3.9 times larger than that in Europeans in whom no significant association was observed (0.08 kg/m(2), P=0.36). This was consistent with the chronological cumulative decrease in the effect size, which decreased steadily in Europeans and reached nonsignificance after 11 studies in 1996. In East Asians, the cumulative effect size decreased after the first reports, but reached a steady state at a significant effect size of 0.24 kg/m(2) in 2000. Although the funnel plot indicated no apparent publication bias, smaller studies tended to report greater differences in BMI, compared with larger studies. CONCLUSIONS: Collectively, these data suggest that the Trp64Arg ADRB3 genetic variant might be associated with BMI in East Asians, but not Europeans. More generally, our study shows the importance of meta-analyses in the field of genetic association studies for common traits. Each genetic variant makes only a small contribution to variation in BMI, and large sample sizes are needed to reliably assess and interpret gene-phenotype associations.

The V103I polymorphism of the MC4R gene and obesity: population based studies and meta-analysis of 29 563 individuals.

BACKGROUND: Previous studies have suggested that a variant in the melanocortin-4 receptor (MC4R) gene is important in protecting against common obesity. Larger studies are needed, however, to confirm this relation. METHODS: We assessed the association between the V103I polymorphism in the MC4R gene and obesity in three UK population based cohort studies, totalling 8304 individuals. We also did a meta-analysis of relevant studies, involving 10 975 cases and 18 588 controls, to place our findings in context. FINDING: In an analysis of all studies, individuals carrying the isoleucine allele had an 18% (95% confidence interval 4-30%, P=0.015) lower risk of obesity compared with non-carriers. There was no heterogeneity among studies and no apparent publication bias. INTERPRETATION: This study confirms that the V103I polymorphism protects against human obesity at a population level. As such it provides proof of principle that specific gene variants may, at least in part, explain susceptibility and resistance to common forms of human obesity. A better understanding of the mechanisms underlying this association will help determine whether changes in MC4R activity have therapeutic potential.

The association between marital adjustment and compliance with antihypertension regimens.

The purpose of this cross-sectional survey was to determine relations between marital adjustment as measured by the Dyadic Adjustment Scale and antihypertension compliance. From seven dependent measures, we found high marital adjustment scores to be significantly correlated with less obesity, lower frequency of forgetting blood pressure medications, and less cessation of blood pressure medicine. These effects were much larger in a younger subsample of respondents who were 28 to 50 years old. The Dyadic Adjustment Scale measures the respondent's perception of the degree of affection and consensus, cohesion, and satisfaction in marriage. We conclude that the perception of positive marital interaction and communication ultimately contributes to controlled blood pressure by helping the patient to maintain healthy weight and to remember and continue taking blood pressure medication.

Health promoting behaviors of family practice residents: do they compare with the general public?

To compare the health promoting behaviors of family medicine residents with those of the general population, data from a survey of 466 residents in the six-state south central region were compared by gender to data from the National Health Interview Survey (NHIS, 1985), adjusted for age, education, and income. The results showed that less than 5% of the family medicine residents were currently smoking cigarettes versus 28% of the NHIS respondents. Daily use of alcohol was significantly lower among men residents than NHIS men, 1.9% versus 13%, but was similar between women residents and NHIS women, 4.9% versus 4.0%. Residents were more likely to consistently use seat belts than the national study population, 74.3% versus 56.8%. There were no significant differences in weight or exercise patterns. However, residents reported a significantly higher incidence of personal or emotional problems during the previous year than NHIS respondents, 50.7% versus 37% for men, and 64.1% versus 49% for women, and were more likely to seek professional help.

Relationship of residents' emotional problems, coping behaviors, and gender.

Family medicine residents were studied to test the hypotheses that a higher incidence and greater severity of personal or emotional problems are associated with a higher incidence of maladaptive coping behaviors among women than men residents. Self-report data were collected from 466 residents in six states on personal or emotional problems and on alcohol use, cigarette smoking, weight, diet, and exercise. The study provides evidence that the women residents experienced a higher incidence and greater severity of personal or emotional problems than men and that these problems were associated with an increased percentage of women than men who had used alcohol during the preceding year, had used alcohol daily, had increased use of alcohol over the two years before the survey, and had had perceptions of being overweight and were on calorie restricted diets. The gender differences in cigarette smoking and frequency of exercise were not significant. The author concludes that residency programs need to provide flexible programs that would better accommodate women's needs and to help residents develop healthy strategies for dealing with stress.