The relationship between microbiota, short chain fatty acids (SCFAs), and obesity remains enigmatic. We employ amplicon sequencing and targeted metabolomics in a large (n = 1904) African origin cohort from Ghana, South Africa, Jamaica, Seychelles, and the US. Microbiota diversity and fecal SCFAs are greatest in Ghanaians, and lowest in Americans, representing each end of the urbanization spectrum. Obesity is significantly associated with a reduction in SCFA concentration, microbial diversity, and SCFA synthesizing bacteria, with country of origin being the strongest explanatory factor. Diabetes, glucose state, hypertension, obesity, and sex can be accurately predicted from the global microbiota, but when analyzed at the level of country, predictive accuracy is only universally maintained for sex. Diabetes, glucose, and hypertension are only predictive in certain low-income countries. Our findings suggest that adiposity-related microbiota differences differ between low-to-middle-income compared to high-income countries. Further investigation is needed to determine the factors driving this association.

Sleep disorders are increasingly being characterized in modern society as contributing to a host of serious medical problems, including obesity and metabolic syndrome. Changes to the microbial community in the human gut have been reportedly associated with many of these cardiometabolic outcomes. In this study, we investigated the impact of sleep length on the gut microbiota in a large cohort of 655 participants of African descent, aged 25–45, from Ghana, South Africa (SA), Jamaica, and the United States (US). The sleep duration was self-reported via a questionnaire. Participants were classified into 3 sleep groups: short (<7hrs), normal (7-<9hrs), and long (≥9hrs). Forty-seven percent of US participants were classified as short sleepers and 88% of SA participants as long sleepers. Gut microbial composition analysis (16S rRNA gene sequencing) revealed that bacterial alpha diversity negatively correlated with sleep length (p<0.05). Furthermore, sleep length significantly contributed to the inter-individual beta diversity dissimilarity in gut microbial composition (p<0.01). Participants with both short and long-sleep durations exhibited significantly higher abundances of several taxonomic features, compared to normal sleep duration participants. The predicted relative proportion of two genes involved in the butyrate synthesis via lysine pathway were enriched in short sleep duration participants. Finally, co-occurrence relationships revealed by network analysis showed unique interactions among the short, normal and long duration sleepers. These results suggest that sleep length in humans may alter gut microbiota by driving population shifts of the whole microbiota and also specific changes in Exact Sequence Variants abundance, which may have implications for chronic inflammation associated diseases. The current findings suggest a possible relationship between disrupted sleep patterns and the composition of the gut microbiota. Prospective investigations in larger and more prolonged sleep researches and causally experimental studies are needed to confirm these findings, investigate the underlying mechanism and determine whether improving microbial homeostasis may buffer against sleep-related health decline in humans.

Long-chain omega-3 PUFAs, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are of increasing interest because of their favorable effect on cardiometabolic risk. This study explores the association between omega 6 and 3 fatty acids intake and cardiometabolic risk in four African-origin populations spanning the epidemiological transition. Data are obtained from a cohort of 2500 adults aged 25–45 enrolled in the Modeling the Epidemiologic Transition Study (METS), from the US, Ghana, Jamaica, and the Seychelles. Dietary intake was measured using two 24 h recalls from the Nutrient Data System for Research (NDSR). The prevalence of cardiometabolic risk was analyzed by comparing the lowest and highest quartile of omega-3 (EPA+ DHA) consumption and by comparing participants who consumed a ratio of arachidonic acid (AA)/EPA + DHA $\le 4:1$ and >4:1. Data were analyzed using multiple variable logistic regression adjusted for age, gender, activity, calorie intake, alcohol intake, and smoking status. The lowest quartile of EPA + DHA intake is associated with cardiometabolic risk 2.16 (1.45, 3.2), inflammation 1.59 (1.17, 2.16), and obesity 2.06 (1.50, 2.82). Additionally, consuming an AA/EPA + DHA ratio of >4:1 is also associated with cardiometabolic risk 1.80 (1.24, 2.60), inflammation 1.47 (1.06, 2.03), and obesity 1.72 (1.25, 2.39). Our findings corroborate previous research supporting a beneficial role for monounsaturated fatty acids in reducing cardiometabolic risk.

Background Non-communicable diseases (NCDs) such as obesity, hypertension (HPT), and type II diabetes (T2D) are of increasing concern in South Africa (SA), with women being more at risk. Authors conducted a scoping review to identify and map the evidence available about the barriers of access to obesity, HPT, and T2D care among women in SA. Methods Arksey and O'Malley's framework for scoping review was used. The search of the literature was completed in the Scopus, Web of Science, and PubMed databases between April and May 2022. Only studies conducted among women in SA were eligible for inclusion. Identified barriers were mapped onto Levesque’s framework of access to health care to determine which points along the chain of accessing NCD health care among women are mostly impacted. Results Seven articles were included in the review: qualitative (n=2), quantitative (n=2), mixed methods (n=2), and grey literature (n=1). The included studies reported barriers of access to HPT and T2D care only, and no study reported barriers to obesity care. Supply-side barriers included lack of knowledge about available services, physician heavy workloads, medicine stock-outs, limited availability of testing equipment, travelling long distances, long waiting times, and delayed referral. Demand-side barriers included women having low self-awareness of NCD status, concerns about confidentiality, perceived discrimination, and poverty. Conclusions The study highlighted barriers related to the availability and accessibility dimension of access to health care, indicating that care for HPT and T2D is often inaccessible, with women often unable to reach health facilities or service providers. There is a pressing need for further research on access to healthcare for obesity, T2D, and HPT for women in South Africa, particularly among women who bear a disproportionately high burden of these conditions.

Objective This cross-sectional study aims to assess the associations between serum leptin, adiponectin, leptin-to-adiponectin ratio (L/A ratio), and metabolic syndrome (MS) and HOMA-IR in five African-origin populations: Ghana, South Africa, Jamaica, Seychelles, and US. Methods Clinical measures included serum glucose, insulin, adipokines, blood pressure and anthropometric measures. MS was determined using the Harmonized criteria. The final sample included 2087 adults. Results After adjusting for age, sex, and fat mass, L/A ratio, unlike HOMA-IR, was significantly associated with MS across all sites (p < 0.001). Within sites, L/A ratio was only associated with MS and HOMA-IR in the US (p < 0.001) and South Africa (p < 0.01), respectively. Leptin was associated with MS in South Africa only (p < 0.05) but was significantly associated with HOMA-IR across all five sites and within the US (p < 0.05). Similarly, adiponectin was associated with HOMA-IR in South Africa (p < 0.05) and with MS across all five sites (p < 0.001) and within each site separately, except Ghana. Conclusions Our study suggests that individuals of the African diaspora in different geographical locations may differ in the determinants of MS. Future studies should investigate the determinants for the disparate relationships between MS, IS and adipokines across different African-origin populations.

Underlying mechanisms by which exposures to toxic metals/metalloids impact obesity and type 2 diabetes (T2DM) risk remain largely unknown. Gut microbiota have been strongly associated with cardiometabolic risk. To assess relationships between high metal exposures, gut dysbiosis, and metabolic dysregulation, we analyzed associations among gut microbiome taxa, dichotomized metal levels (arsenic, lead, mercury, cadmium), clinical measures (BMI, fasting blood glucose, blood pressure), and diagnoses (hypertension, obesity, diabetes) in 178 African-origin adults (52% female, mean age = 43.0 ± 6.4 years) from Ghana, South Africa, Jamaica, Seychelles, and USA. High vs. low lead and arsenic levels had a significant effect on beta diversity (p < 0.05). Seventy-one taxa were associated with high lead levels: 30 with elevated BMI, 22 with T2DM, and 23 with elevated fasting blood glucose (p < 0.05); 115 taxa were associated with high arsenic levels: 32 with elevated BMI, 33 with T2DM, and 26 with elevated blood glucose (p < 0.05). Porphyrin metabolism was the most enriched metabolic pathway in taxa associated with higher lead and arsenic exposure. These data provide the first findings from African-origin adults that demonstrate the association between the gut microbiome with lead and arsenic exposure and obesity and T2DM risk.