Gut microbiome profiling of a rural and urban South African cohort reveals biomarkers of a population in lifestyle transition.

BACKGROUND: Comparisons of traditional hunter-gatherers and pre-agricultural communities in Africa with urban and suburban Western North American and European cohorts have clearly shown that diet, lifestyle and environment are associated with gut microbiome composition. Yet, little is known about the gut microbiome composition of most communities in the very diverse African continent. South Africa comprises a richly diverse ethnolinguistic population that is experiencing an ongoing epidemiological transition and concurrent spike in the prevalence of obesity, largely attributed to a shift towards more Westernized diets and increasingly inactive lifestyle practices. To characterize the microbiome of African adults living in more mainstream lifestyle settings and investigate associations between the microbiome and obesity, we conducted a pilot study, designed collaboratively with community leaders, in two South African cohorts representative of urban and transitioning rural populations. As the rate of overweight and obesity is particularly high in women, we collected single time-point stool samples from 170 HIV-negative women (51 at Soweto; 119 at Bushbuckridge), performed 16S rRNA gene sequencing on these samples and compared the data to concurrently collected anthropometric data. RESULTS: We found the overall gut microbiome of our cohorts to be reflective of their ongoing epidemiological transition. Specifically, we find that geographical location was more important for sample clustering than lean/obese status and observed a relatively higher abundance of the Melainabacteria, Vampirovibrio, a predatory bacterium, in Bushbuckridge. Also, Prevotella, despite its generally high prevalence in the cohorts, showed an association with obesity. In comparisons with benchmarked datasets representative of non-Western populations, relatively higher abundance values were observed in our dataset for Barnesiella (log2fold change (FC) = 4.5), Alistipes (log2FC = 3.9), Bacteroides (log2FC = 4.2), Parabacteroides (log2FC = 3.1) and Treponema (log2FC = 1.6), with the exception of Prevotella (log2FC = - 4.7). CONCLUSIONS: Altogether, this work identifies putative microbial features associated with host health in a historically understudied community undergoing an epidemiological transition. Furthermore, we note the crucial role of community engagement to the success of a study in an African setting, the importance of more population-specific studies to inform targeted interventions as well as present a basic foundation for future research.

Experience of hypoglycaemia is associated with changes in beliefs about diabetes in patients with type 2 diabetes.

AIM: Hypoglycaemia may have a detrimental impact on quality of life for patients with Type 2 diabetes. There are few clinical studies exploring the impact of experiencing hypoglycaemia on beliefs about diabetes and health status. The aim of this study was to explore associations between experience of hypoglycaemia and changes in diabetes beliefs and self-reported health status in patients with non-insulin-treated Type 2 diabetes using a blood glucose meter. METHODS: One-year prospective cohort analysis of 226 patients recruited to a randomized trial evaluating the impact of self-monitoring of blood glucose. Self-reported hypoglycaemia over 1 year was categorized into three groups: (1) no experience of hypoglycaemia; (2) blood glucose measurements < 4 mmol/l with no associated symptoms of hypoglycaemia (grade 1); and (3) symptomatic hypoglycaemia (grade 2 and 3). Measures of beliefs about diabetes (Revised Illness Perception Questionnaire) and health status (EuroQol-5D) were assessed at baseline and 1 year. Differences in mean changes over 1 year were explored with analyses of covariance. RESULTS: There was a significant increase in mean score in beliefs about personal control (1.14; 95%CI 0.14-2.14) among those experiencing grade 1 hypoglycaemia compared with those not experiencing hypoglycaemia. There were no significant differences in changes in health status between groups, with small overall changes that were inconsistent between groups. CONCLUSIONS: This study does not provide support for a long-term adverse impact on beliefs about diabetes or health status from the experience of mild symptomatic hypoglycaemia, in well-controlled, non-insulin-treated patients with Type 2 diabetes using self-monitoring of blood glucose.

Blood glucose self-monitoring in type 2 diabetes: a randomised controlled trial.

OBJECTIVES: To determine whether self-monitoring of blood glucose (SMBG), either alone or with additional instruction in incorporating the results into self-care, is more effective than usual care in improving glycaemic control in non-insulin-treated diabetes. DESIGN: An open, parallel group randomised controlled trial. SETTING: 24 general practices in Oxfordshire and 24 in South Yorkshire, UK. PARTICIPANTS: Patients with non-insulin-treated type 2 diabetes, aged > or = 25 years and with glycosylated haemoglobin (HbA1c) > or = 6.2%. INTERVENTIONS: A total of 453 patients were individually randomised to one of: (1) standardised usual care with 3-monthly HbA1c (control, n = 152); (2) blood glucose self-testing with patient training focused on clinician interpretation of results in addition to usual care (less intensive self-monitoring, n = 150); (3) SMBG with additional training of patients in interpretation and application of the results to enhance motivation and maintain adherence to a healthy lifestyle (more intensive self-monitoring, n = 151). MAIN OUTCOME MEASURES: The primary outcome was HBA1c at 12 months, and an intention-to-treat analysis, including all patients, was undertaken. Blood pressure, lipids, episodes of hypoglycaemia and quality of life, measured with the EuroQol 5 dimensions (EQ-5D), were secondary measures. An economic analysis was also carried out, and questionnaires were used to measure well-being, beliefs about use of SMBG and self-reports of medication taking, dietary and physical activities, and health-care resource use. RESULTS: The differences in 12-month HbA1c between the three groups (adjusted for baseline HbA1c) were not statistically significant (p = 0.12). The difference in unadjusted mean change in HbA1c from baseline to 12 months between the control and less intensive self-monitoring groups was -0.14% [95% confidence interval (CI) -0.35 to 0.07] and between the control and more intensive self-monitoring groups was -0.17% (95% CI -0.37 to 0.03). There was no evidence of a significantly different impact of self-monitoring on glycaemic control when comparing subgroups of patients defined by duration of diabetes, therapy, diabetes-related complications and EQ-5D score. The economic analysis suggested that SMBG resulted in extra health-care costs and was unlikely to be cost-effective if used routinely. There appeared to be an initial negative impact of SMBG on quality of life measured on the EQ-5D, and the potential additional lifetime gains in quality-adjusted life-years, resulting from the lower levels of risk factors achieved at the end of trial follow-up, were outweighed by these initial impacts for both SMBG groups compared with control. Some patients felt that SMBG was helpful, and there was evidence that those using more intensive self-monitoring perceived diabetes as having more serious consequences. Patients using SMBG were often not clear about the relationship between their behaviour and the test results. CONCLUSIONS: While the data do not exclude the possibility of a clinically important benefit for specific subgroups of patients in initiating good glycaemic control, SMBG by non-insulin-treated patients, with or without instruction in incorporating findings into self-care, did not lead to a significant improvement in glycaemic control compared with usual care monitored by HbA1c levels. There was no convincing evidence to support a recommendation for routine self-monitoring of all patients and no evidence of improved glycaemic control in predefined subgroups of patients.

Self-monitoring of blood glucose changed non-insulin-treated Type 2 diabetes patients' beliefs about diabetes and self-monitoring in a randomized trial.

AIMS: To determine whether differences in beliefs about diabetes and its treatment resulted from different intensities of self-monitoring of blood glucose (SMBG) in non-insulin treated patients with Type 2 diabetes in the Diabetes Glycaemic Education and Monitoring (DiGEM) trial. METHODS: Patients (n = 453) were randomized to usual care, less-intensive SMBG and more intensive SMBG. Beliefs about diabetes were measured with a standard questionnaire (the revised Illness Perceptions Questionnaire; IPQ-R). Changes in beliefs were analysed using analysis of covariance (ancova) with adjustment for baseline values. Mediation analyses assessed whether differences in behavioural outcomes between groups could be attributed to differences in beliefs. RESULTS: Completed questionnaires were returned by 339 patients (74.8%). Respondents were mean (+/- sd) age 65.9 +/- 10 years and with diabetes duration of 4.8 +/- 4.7 years (median 36, range 1-384 months). Concerns about the consequences of diabetes increased in both self-monitoring groups, relative to control subjects [P = 0.004; Cohen's d standardized effect size = 0.19 less intensive and d = 0.36 more intensive monitoring]. No other beliefs about diabetes differed between groups. Beliefs about the importance of self-testing increased in both self-monitoring groups relative to the usual-care group (P < 0.001; d = 0.57 less intensive and d = 0.63 more intensive monitoring). Changes in psychological well-being did not differ between groups, but control patients reported greater increases in general (P = 0.014) and specific (P < 0.001) dietary adherence than did patients in the self-monitoring groups. These outcomes were not mediated by intervention-related changes in beliefs. CONCLUSIONS: Despite changes in some beliefs about diabetes differing between groups there were no corresponding changes in self-reported health behaviours. This suggests that changes in illness beliefs resulting from SMBG do not cause changes in diabetes-related health behaviours.