Nutrition, growth and body mass index of Baka Pygmy children and adults
Baka Pygmies suffer from poorer health and life expectancy than sympatric peoples because of greater poverty and insufficient health care. We use anthropometric and health data to estimate stunting, wasting, and obesity frequencies for a large sample of Baka Pygmy children living in southeastern Cameroon. We monitored the body mass index (BMI) of adult Baka and compared it with their Bantu neighbours.
The work was part of the Darwin Initiative project “Enabling Baka attain food security, improved health and sustain biodiversity” from 2017 to 2020, led by Dr Julia Fa from Manchester Metropolitan University. Nature Heritage provided analytic capacity and writing skills.
- Funk SM et al. 2020. Understanding Growth and Malnutrition in Baka Pygmy Children. Human Ecology 48:293–306.
We determined stunting, wasting, and obesity frequencies in a total 1092 2-to-12 year old Baka Pygmy children from anthropometric and health data gathered in 34 villages in the Djoum-Mintom region in southeastern Cameroon in four health campaigns in 2010 and 2017–9. We compare these to the WHO Child Growth Standards, Amazonian Tsiname growth references for inter-population comparisons and the study population itself. Population-specific growth charts were constructed using GAMLSS modelling.
Our results show that Baka children have one of the highest global rates of stunting relative to the WHO child growth standard with 57.8% for 2-to-12 year olds and 64% and 73% for 2-to-4 year old girls and boys, respectively. Frequencies of wasting, overweight, and low BMI were low at 3.4%, 4.6% and 4.3%, respectively, for 2-to-12 year olds. Underweight was at 25.5%, in the upper range for sub-Saharan Africa. Edemas indicated rare severe malnutrition (0.3%). Uncertainties in age estimation had dramatic effects on the reliability of estimated individual z-scores but distributions of z-scores were robust at a population level.
In the context of the recent evidence for genetic adaptation of the Pygmies’ small stature to the tropical forest environment we argue that WHO child standards for weight and BMI are applicable. However, standards for height are clearly not adequate for Pygmy people. To achieve UN Sustainable Development Goals, we recommend that Pygmy specific growth standards are developed for the various, genetically differing Pygmy tribes.
- Funk SM, Palomo Guerra B, de Mena Martínez N, Ickowitz A, Fa JE. 2020. Divergent trajectories of BMI over age for adult Baka Pygmy people and their sympatric non-Pygmy populations. Human Ecology 4: 143–153
Differences in socioeconomic conditions and health have been reported for African Pygmies and their sympatric populations of other ethnic groups.
We collected anthropometric data in southern Cameroon from Baka and their Bantu neighbours, and also extracted data from the five available and representative Demographic and Health Surveys (DHS) in sub-Saharan African countries that have Pygmy populations.
Our results show that the Baka exhibited a weak but significant decline of body mass index (BMI) with age (p = 0.003) without a sex difference. At a larger geographical scale, all five DHS surveys revealed flat or negative slopes for Pygmy BMI with age. Except for one non-Pygmy ethnic group, the slope was less than for all DHS- surveyed non-Pygmy African ethnicities. Pygmy populations were the least wealthy in all surveys, but no pattern for anaemia levels versus BMI emerged. We argue that the declining or stagnant trajectory of Pygmy BMI over age is most concerning, since this sets them apart not only from all other ethnic groups in the region, but from the general trend of increasing body weight over age.
We suggest that our results do not reflect the influence of ethnicity per se, but the fact Pygmy populations are socially and materially deprived groups. These findings are fully aligned with the extraordinary high premature death rate among the Baka and need to be addressed for sustainable development initiatives to be effectively implemented.