The Relationship Between Urbanization and White Blood Cell Count: A Case Study of the Turkana People of Kenya

Abstract

Non-communicable diseases (NCDs) are responsible for more than 75 percent of all deaths each year. Due to its effects on both lifestyle and biological factors, such as white blood cell (WBC) count, urbanization is one of the most prominent factors responsible for increased rates of NCDs. Movement of individuals from Turkana to Laikipia county in northwest Kenya has increased in recent years due to modernization, thus creating the opportunity to investigate the health differences of individuals in urban versus rural/pastoral lifestyles. We tested the hypotheses that WBC count differs between nomadic Turkana, settled Turkana, and Turkana residing in Laikipia county. The additional hypothesis that WBC count differs depending on dietary measures, non-geographic urbanicity measures, and biomarkers was also tested. Linear models revealed that pastoralist Turkana have significantly higher (p < 0.05) levels of basophils and eosinophils than non-pastoralist, rural Turkana. Lymphocyte levels in urban Turkana were significantly higher than both pastoralists and non-pastoralist, rural Turkana. Contrarily, neutrophil levels were significantly lower in urban Turkana than non-pastoralist, rural individuals. Neutrophil levels decreased significantly with reported animal product consumption. Lymphocyte levels increased significantly with fruit/vegetable and market carbohydrate consumption. For biomarkers, decreasing neutrophil counts was associated with increasing waist circumference. These findings support the proposition that urban environments may increase NCD and metabolic syndrome susceptibility through WBC count changes. We hope these findings encourage further research into the relationship between urbanization and WBC content, metabolic syndrome, and NCDs to aid in combating the chronic disease epidemic.