Preliminarty study on the relationship between environmental low selenium exposure and blood pressure in rural elderly Chinese

Objective To preliminarily explore the relationship between environmental low selenium exposure and blood pressure in rural elderly Chinese. Methods Respectively 500 subjects aged 65 or older were recruited from environmental low and optimal selenium rural areas. Questionnaire survey and physical measurement including blood pressure, were carried out. Finger nail samples were collected and the trace amount of selenium was detected with 2, 3-diaminonaphthalenet fluorometric determination method. Results Finger nail selenium level [ （0.211 ± 0.057 ）μg/g ] of subjects in low selenium areas was significantly lower than that [ （0.431 ±0.136） μg/g ] of subjects in optimal selenium areas （t = 33.87, P 〈 0.05）. Systolic blood pressure （SBP） and diastolic blood pressure（DBP） were positively associated with finger nail selenium levels in overall population（rSBP = 0.231 ,rDBP = 0.188, all P 〈 0.05）, but no such association was observed in population of optimal selenium areas or low selenium areas. The detection rate of hypertension [ 68.4% （342/500）] in optimal selenium areas was significantly higher than that [ 41.2% （206/500） ] of low selenium areas （χ2 = 74.672, P 〈 0.05）, but no significant difference was observed among 5 groups of subjects in different selenium quintiles（all P 〉 0.05）. Conclusions Low environmental selenium exposure may be associated with blood pressure in elderly population. Large-scale and longitudinal population studies are needed to verify the possible association. Key words: Selenium;  Environmental exposure ;  Blood pressure;  Elderly population