Low salivary cortisol and elevated depressive affect among rural men in Botswana: reliability and validity of laboratory results

Most research on hypothalamic-pituitary-adrenal axis function under aversive conditions has focused on relatively increased acute episodic, or chronic secretions as an operationalization of "stress." Severe or recurrent stress, perhaps in interaction with individual characteristics, results in chronically decreased HPA function among some persons suffering from posttraumatic stress disorder. Little evidence exists to assess the population distribution of chronic low cortisol in different free-ranging human populations, as a manifestation of past trauma or stress. This study reports findings of chronically depressed ambulatory salivary cortisol among rural-dwelling Batswana men (n=30) compared with men living in Gaborone (n=34), the capital of Botswana, based on repeated ambulatory sampling. Out of 914 saliva samples analyzed by radioimmunoassay, 268 (29.3%) samples (41 urban, 227 rural) were below the minimum detectable dose (