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.

Gender Norms and HIV Testing/Treatment Uptake: Evidence from a Large Population-Based Sample in South Africa.

How does the endorsement of different dimensions of gender norms by men and/or women influence their use of HIV testing and antiretroviral treatment? This question was examined using data from a 2014 population-based survey of 1053 women and 1004 men, ages 18-49, in rural South Africa. We used a global measure for views toward gender norms (the GEM Scale), plus four subsets of scale items (all reliabilities ≥ 0.7). In multivariate analyses using the global measure, endorsement of inequitable gender norms was associated with more testing (AOR 2.47, p < 0.01) and less treatment use (AOR 0.15, p < 0.01) among women but not men. When examining specific subsets of inequitable norms (e.g., endorsing men as the primary decision-maker), decreased odds of treatment use was found for men as well (AOR 0.18, p < 0.01). Careful attention to the role specific gender norms play in HIV service uptake can yield useful programmatic recommendations.

Gross motor skills of South African preschool-aged children across different income settings.

OBJECTIVES: No studies have investigated gross motor skill (GMS) proficiency of preschool-aged children across different income settings in South Africa. Research from high-income countries suggests that children from low-income settings display poorer GMS proficiency compared to higher-income peers. This study aimed to (1) describe GMS proficiency of preschool-aged children in urban high-income (UH), urban low-income (UL) and rural low-income (RL) settings; and (2) explore differences in proficiency between income settings and sex. DESIGN: Descriptive cross-sectional study. METHODS: The Test of Gross Motor Development-Edition 2 (TGMD-2) was used to assess GMS. The TGMD-2 gross motor quotient, standardised scores and raw scores were used to describe proficiency. RESULTS: GMS proficiency was assessed in n=259 3-6-year-old children (n=46 UH, n=91 UL, n=122 RL). Overall, 93% of the children were classified as having 'average' or better GMS. According to TGMD-2 standardised scores, the RL children performed significantly better than UH and UL children (p=0.028 and p=0.009, respectively). RL children were significantly more proficient than UH and UL children in the strike and horizontal jump when comparing raw scores. Overall, boys performed significantly better than girls in the strike, stationary dribble, kick and leap when comparing raw scores (all p<0.001). CONCLUSIONS: This study reports high GMS proficiency in preschool-aged children across income settings in South Africa. The factors associated with higher GMS in low-income settings are not immediately obvious. Thus, future research should explore potential factors and identify opportunities to ensure that GMS proficiency is capitalised on as preschool-aged children enter formal schooling.

The associations between interpersonal violence and psychological distress among rural and urban young women in South Africa.

BACKGROUND: Approximately 25% of the world's population consists of young people. The experience of violence peaks during adolescence and the early adult years. A link between personal experience of violence and mental health among young people has been demonstrated but rural-urban differences in these associations are less well known in low to middle income countries. The aim of this study was to investigate the associations between interpersonal violence and psychological distress among rural and urban young women. METHODS: Data on experiences of violence and psychological distress were collected from a total of 926 non-pregnant young women aged between 18 and 22 years of age in rural and urban sites in South Africa. The General Health Questionnaire-28 was used to assess psychological distress as an indicator of mental health. Generalised structural equation models were employed to assess potential pathways of association between interpersonal violence and psychological distress. RESULTS: Thirty-four percent of the urban young women (n = 161) reported psychological distress compared to 18% of rural young women (n = 81). In unadjusted analysis, exposure to interpersonal violence doubled the odds of psychological distress in the urban adolescents and increased the odds 1.6 times in the rural adolescents. In adjusted models, the relationship remained significant in the urban area only (OR 1.84, 95% CI 1.13-3.00). Rural residence seemed protective against psychological distress (OR 0.41, 95% CI 0.24-0.69). Structural equation modelling did not reveal any direct association between exposure to interpersonal violence and psychological distress among rural young women. Stressful household events were indirectly associated with psychological distress, mediated by violence among young women in the urban area. CONCLUSION: The relationship between violence and psychological distress differs between urban and rural-residing young women in South Africa, and is influenced by individual, household and community (contextual) factors.

H3Africa AWI-Gen Collaborative Centre: a resource to study the interplay between genomic and environmental risk factors for cardiometabolic diseases in four sub-Saharan African countries.

Africa is experiencing a rapid increase in adult obesity and associated cardiometabolic diseases (CMDs). The H3Africa AWI-Gen Collaborative Centre was established to examine genomic and environmental factors that influence body composition, body fat distribution and CMD risk, with the aim to provide insights towards effective treatment and intervention strategies. It provides a research platform of over 10 500 participants, 40-60 years old, from Burkina Faso, Ghana, Kenya and South Africa. Following a process that involved community engagement, training of project staff and participant informed consent, participants were administered detailed questionnaires, anthropometric measurements were taken and biospecimens collected. This generated a wealth of demographic, health history, environmental, behavioural and biomarker data. The H3Africa SNP array will be used for genome-wide association studies. AWI-Gen is building capacity to perform large epidemiological, genomic and epigenomic studies across several African counties and strives to become a valuable resource for research collaborations in Africa.

Temporal association of infant immunisation with pneumococcal conjugate vaccine on the ecology of Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus nasopharyngeal colonisation in a rural South African community.

BACKGROUND: Immunisation of children with pneumococcal conjugate vaccines (PCV) may affect the bacterial-ecology of the nasopharynx, including colonisation by Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. The aim of this study was to evaluate the effect of infant PCV-immunisation on the nasopharyngeal ecology of these potentially pathogenic bacteria in a rural African setting. METHODS: Two cross sectional surveys were undertaken from May to October in 2009 (Period-1) which coincided with the introduction of 7-valent PCV (PCV7) and in May-October 2011 (Period-2). Consenting household members, where there was a child <2 years of age in residence, had nasopharyngeal swabs undertaken for culture. RESULTS: From Period-1 to Period-2 in children 0-2 years and 3-12 years, prevalence of overall S. pneumoniae colonisation decreased from 74.9% to 67.0% (p<0.001) and H. influenzae declined among children 3-12 years (55.1-45.3%, p<0.001) but not among those <2 years. The prevalence of S. aureus remained unchanged in all children. Competitive associations were found between S. pneumoniae and S. aureus and between H. influenzae and S. aureus among children. In individuals >12 years, the prevalence of colonisation decreased from 11.2% to 6.8%, 16.7% to 8.8% and 31.2% to 23.7% for S. pneumoniae, H. influenzae and S. aureus, respectively; p<0.001 for all comparions. Synergistic relationships for S. aureus with H. influenzae and S. pneumoniae were observed in both periods among this group.

Early detection of carcinomas of the right colon: role of hemoglobin and mean corpuscular volume.

The authors suggest that utilization of the hemoglobin-mean corpuscular volume index (HGB-MCV) can serve as an approach to the early detection of certain colon carcinomas. The results of a study of 50 patients using this index are analyzed.