Arterial stiffness and cardiometabolic phenotype of Cameroonian Pygmies and Bantus

Pygmies living in the Central African rainforest with a traditional hunter-gatherer lifestyle have a low incidence of cardiovascular diseases. Because of progressive loss of traditional habitat and ancestral lands, some Pygmies have migrated to urban areas and adopt specific Bantu lifestyles such as increased salt consumption and a sedentary way of life. We tested the hypothesis that migrant Pygmies could present with hemodynamic and metabolic characteristics different from those of traditional in-situ Pygmies and possibly closer to those of Bantu farmers.

The study included 148 Pygmies (94 traditional and 54 migrants) and 164 Bantus. Peripheral and central hemodynamics, aortic pulse wave velocity (PWV), and augmentation index corrected for heart rate (AIx) were measured, as well as fasting lipid profile. Urinary sodium and potassium excretion was also measured on a morning spot.

Compared to Bantus, Pygmies had lower height (even between men and women, but men were taller than women in the three groups), weight, waist and hip circumference, peripheral and central blood pressure, total, low-density lipoprotein, and high-density lipoprotein cholesterol and apolipoprotein B100 levels, sodium urinary excretion, and lower prevalence of the metabolic syndrome. By contrast, they had a higher waist-to-hip ratio, and higher triglycerides levels, as compared to Bantu farmers. PWV and AIx did not differ between Bantus and Pygmies. Compared to traditional in-situ Pygmies, migrant Pygmies were not taller when adjusted for sex, had lower brachial and central blood pressure, higher PWV (adjusted for mean arterial pressure, BMI, and sex), and higher apolipoprotein B100 levels. In the whole population, multivariable analysis revealed that PWV was independently associated with age, weight, height, mean arterial pressure, total cholesterol, and hip circumference, whereas AIx was independently related to age, sex, height, heart rate, diastolic blood pressure, and group (from Bantu farmers to Pygmies).

Comparisons between Bantus and Pygmies, and between migrant Pygmies and traditional in-situ Pygmies, showed mixed results, with favorable and deleterious hemodynamic and metabolic characteristics in all groups. This could be due to increased contacts between these populations, which blunt the expected differences and because the beneficial effects of the hunter-gatherer subsistence mode of traditional in-situ Pygmies are counterbalanced by unhealthy behavioral habits.