Background: The consistent finding of higher prevalence of hypertension in US blacks compared to whites has led to speculation that African-origin populations are particularly susceptible to this condition. Large surveys now provide new information on this issue. Methods: Using a standardized analysis strategy we examined prevalence estimates for 8 white and 3 black populations (N = 85,000 participants). Results: The range in hypertension prevalence was from 27 to 55% for whites and 14 to 44% for blacks. Conclusions: These data demonstrate that not only is there a wide variation in hypertension prevalence among both racial groups, the rates among blacks are not unusually high when viewed internationally. These data suggest that the impact of environmental factors among both populations may have been under-appreciated.

Severe acute malnutrition in childhood manifests as oedematous (kwashiorkor, marasmic kwashiorkor) and non-oedematous (marasmus) syndromes with very different prognoses. Kwashiorkor differs from marasmus in the patterns of protein, amino acid and lipid metabolism when patients are acutely ill as well as after rehabilitation to ideal weight for height. Metabolic patterns among marasmic patients define them as metabolically thrifty, while kwashiorkor patients function as metabolically profligate. Such differences might underlie syndromic presentation and prognosis. However, no fundamental explanation exists for these differences in metabolism, nor clinical pictures, given similar exposures to undernutrition. We hypothesized that different developmental trajectories underlie these clinical-metabolic phenotypes: if so this would be strong evidence in support of predictive adaptation model of developmental plasticity. We reviewed the records of all children admitted with severe acute malnutrition to the Tropical Metabolism Research Unit Ward of the University Hospital of the West Indies, Kingston, Jamaica during 1962–1992. We used Wellcome criteria to establish the diagnoses of kwashiorkor (n = 391), marasmus (n = 383), and marasmic-kwashiorkor (n = 375). We recorded participants' birth weights, as determined from maternal recall at the time of admission. Those who developed kwashiorkor had 333 g (95% confidence interval 217 to 449, p<0.001) higher mean birthweight than those who developed marasmus. These data are consistent with a model suggesting that plastic mechanisms operative in utero induce potential marasmics to develop with a metabolic physiology more able to adapt to postnatal undernutrition than those of higher birthweight. Given the different mortality risks of these different syndromes, this observation is supportive of the predictive adaptive response hypothesis and is the first empirical demonstration of the advantageous effects of such a response in humans. The study has implications for understanding pathways to obesity and its cardio-metabolic co-morbidities in poor countries and for famine intervention programs.

The prevalence of obesity has increased in societies of all socio-cultural backgrounds. To date, guidelines set forward to prevent obesity have universally emphasized optimal levels of physical activity. However there are few empirical data to support the assertion that low levels of energy expenditure in activity is a causal factor in the current obesity epidemic are very limited. The Modeling the Epidemiologic Transition Study (METS) is a cohort study designed to assess the association between physical activity levels and relative weight, weight gain and diabetes and cardiovascular disease risk in five population-based samples at different stages of economic development. Twenty-five hundred young adults, ages 25-45, were enrolled in the study; 500 from sites in Ghana, South Africa, Seychelles, Jamaica and the United States. At baseline, physical activity levels were assessed using accelerometry and a questionnaire in all participants and by doubly labeled water in a subsample of 75 per site. We assessed dietary intake using two separate 24-hour recalls, body composition using bioelectrical impedance analysis, and health history, social and economic indicators by questionnaire. Blood pressure was measured and blood samples collected for measurement of lipids, glucose, insulin and adipokines. Full examination including physical activity using accelerometry, anthropometric data and fasting glucose will take place at 12 and 24 months. The distribution of the main variables and the associations between physical activity, independent of energy intake, glucose metabolism and anthropometric measures will be assessed using cross-section and longitudinal analysis within and between sites. METS will provide insight on the relative contribution of physical activity and diet to excess weight, age-related weight gain and incident glucose impairment in five populations' samples of young adults at different stages of economic development. These data should be useful for the development of empirically-based public health policy aimed at the prevention of obesity and associated chronic diseases.

While some of the variance observed in adiposity and weight change within populations can be accounted for by traditional risk factors, a new factor, the gut microbiota, has recently been associated with obesity. However, the causal mechanisms through which the gut microbiota and its metabolites, short chain fatty acids (SCFAs) influence obesity are unknown, as are the individual obesogenic effects of the individual SCFAs (butyrate, acetate and propionate). This study, METS-Microbiome, proposes to examine the influence of novel risk factors, the gut microbiota and SCFAs, on obesity, adiposity and weight change in an international established cohort spanning the epidemiologic transition. The parent study; Modeling the Epidemiologic Transition Study (METS) is a well-established and ongoing prospective cohort study designed to assess the association between body composition, physical activity, and relative weight, weight gain and cardiometabolic disease risk in five diverse population-based samples in 2500 people of African descent. The cohort has been prospectively followed since 2009. Annual measures of obesity risk factors, including body composition, objectively measured physical activity and dietary intake, components which vary across the spectrum of social and economic development. In our new study; METS-Microbiome, in addition to continuing yearly measures of obesity risk, we will also measure gut microbiota and stool SCFAs in all contactable participants, and follow participants for a further 3 years, thus providing one of the largest gut microbiota population-based studies to date. This new study capitalizes upon an existing, extensively well described cohort of adults of African-origin, with significant variability as a result of the widespread geographic distributions, and therefore variation in the environmental covariate exposures. The METS-Microbiome study will substantially advance the understanding of the role gut microbiota and SCFAs play in the development of obesity and provide novel obesity therapeutic targets targeting SCFAs producing features of the gut microbiota. Registered NCT03378765 Date first posted: December 20, 2017.

Malnutrition below 5 years remains a global health issue. Severe acute malnutrition (SAM) presents in childhood as oedematous (kwashiorkor) or nonoedematous (marasmic) forms, with unknown long-term cardiovascular consequences. We hypothesized that cardiovascular structure and function would be poorer in SAM survivors than unexposed controls. We studied 116 adult SAM survivors, 54 after marasmus, 62 kwashiorkor, and 45 age/sex/body mass index–matched community controls who had standardized anthropometry, blood pressure, echocardiography, and arterial tonometry performed. Left ventricular indices and outflow tract diameter, carotid parameters, and pulse wave velocity were measured, with systemic vascular resistance calculated. All were expressed as SD scores. Mean (SD) age was 28.8±7.8 years (55% men). Adjusting for age, sex, height, and weight, SAM survivors had mean (SE) reductions for left ventricular outflow tract diameter of 0.67 (0.16; P <0.001), stroke volume 0.44 (0.17; P =0.009), cardiac output 0.5 (0.16; P =0.001), and pulse wave velocity 0.32 (0.15; P =0.03) compared with controls but higher diastolic blood pressures (by 4.3; 1.2–7.3 mm Hg; P =0.007). Systemic vascular resistance was higher in marasmus and kwashiorkor survivors (30.2 [1.2] and 30.8 [1.1], respectively) than controls 25.3 (0.8), overall difference 5.5 (95% confidence interval, 2.8–8.4 mm Hg min/L; P <0.0001). No evidence of large vessel or cardiac remodeling was found, except closer relationships between these indices in former marasmic survivors. Other parameters did not differ between SAM survivor groups. We conclude that adult SAM survivors had smaller outflow tracts and cardiac output when compared with controls, yet markedly elevated peripheral resistance. Malnutrition survivors are thus likely to develop excess hypertension in later life, especially when exposed to obesity.

Cardiovascular disease (CVD) causes 12.4 million deaths annually, most (9.6 million) occurring in developing countries. Hypertension, the most common CVD, arises within the context of obesity, but the underlying mechanisms remain obscure. Obesity and salt intake are two important risk factors for hypertension and are the focus of this paper. Traditional African populations show a low prevalence of hypertension, but hypertension is more common in migrant African populations in the West than in other ethnic groups. One explanation is genetic, but no causative gene has been confidently identified. Nongenetic susceptibilities such as fetal programming are an alternative explanation. Hypothetically, fetal programming induced by transient stimuli permanently alters fetal structure and function at the cellular, organ and whole-body levels. Birth weight is inversely related to blood pressure and hypertension risk, suggesting that susceptibility to hypertension risk factors such as obesity and salt sensitivity are themselves programmed. In support of this hypothesis, obesity (especially central obesity) is also inversely related to size at birth. Likewise, salt sensitivity might derive from undernutrition in utero, reducing the nephron number and resetting the pressure-natriuresis curve rightward. However, no robust human data or evidence of enhanced salt sensitivity among African-origin populations exist. In the United States, blacks have a greater prevalence of low birth weight than whites, suggesting that the higher prevalence of hypertension among blacks is related to fetal programming. Nevertheless, we need to be scrupulous in ascribing risk to the myriad other confounders of this relationship, including environmental and behavioral correlates of ethnicity, before concluding that excess risk of hypertension in Africans is programmed in utero.