The length of telomeres in white blood cells, or leukocytes, varies significantly among sub-Saharan African populations, according to a study published in The American Journal of Human Genetics. The researchers found that leukocyte telomere length (LTL) is negatively associated with malaria endemicity and may be influenced by genetic and environmental factors. This association between malaria and LTL appears to be larger than any other known exposure or behavior that has been studied.
Telomeres are repetitive DNA sequences that protect the ends of chromosomes from damage, and LTL is known to vary between individuals, with those of African ancestry generally having longer telomeres. LTL shortens with age and is a predictor of aging-related diseases and mortality. While LTL is highly heritable, the majority of large-scale studies have focused on populations of European ancestry, limiting our understanding of the genetic and environmental factors that influence LTL variation.
Little is known about the factors that have shaped the vast LTL variation across sub-Saharan African populations, including genetic, environmental, and evolutionary influences. Recent studies have shown a link between malaria infection and telomere shortening, but it remains unclear whether repeated malaria exposure throughout life has a lasting effect on LTL. The study aimed to examine LTL in diverse populations across Africa to better understand the impact of malaria and other factors on telomere length.
The results revealed significant variation in LTL among populations, with San hunter-gatherers from Botswana having the longest telomeres and Fulani pastoralists from Cameroon having the shortest telomeres. Genetic factors explained about half of the LTL variation among individuals, with LTL being shorter in adults from regions of high malaria endemicity compared to those from regions with low malaria exposure. The potential impact of malaria on LTL reported in this study appears larger than other environmental factors that affect telomere length.
The study suggests that exposure to malaria, through the destruction and replenishment of red blood cells, may play a role in shortening LTL. Longitudinal studies in children and adults from regions of high and low malaria endemicity would provide more insight into the relationship between malaria and LTL dynamics. This research was supported by various grants and organizations, highlighting the importance of understanding telomere length variation across diverse populations.
