Rural areas of Punjab in India have been found to have soil rich in selenium (Se); about 2160 hectare area is seleniferous and is populated by about 10,000 inhabitants. Selenium concentrations in these villages were reported to be as high as 65 times over non-seleniferous areas. The aim of this cross-sectional study was to evaluate selenium levels in blood, hair and nails in a group of subjects living in this area, and to evaluate the correlation between selenium exposure levels and a relevant cardiovascular risk factor and blood pressure. 

A total of 680 human subjects were recruited in this study, with a male/female ratio of 0.65 and a median age of 43 (IQR 32-52). Medium selenium levels in blood, hair and nail were 86.7 μg/l (IQR 55.9-200.3), 20.7 μg/g (IQR 12.6-40.3) and 56.9 μg/g (IQR 42.8-83.9), respectively, with lower levels in women in all three kind of samples. Concerning systolic blood pressure, Pearson’s correlation coefficients were 0.102 (95 % CI -0.025 to 0.226, p=0.116); 0.076 (95% CI -0.010 to 0.160, p=0.085); 0.072 (95% CI -0.015 to 0.157, p=0.104) with blood, hair and nail, respectively. For diastolic blood pressure, Pearson’s correlation coefficients are 0.106 (95% CI -0.022 to 0.230, p=0.104), 0.036 (95% CI -0.050 to 0.122, p=0.409), 0.049 (95% CI -0.038 to 0.135, p=0.272), respectively. 

Our findings indicate a positive correlation between selenium content in blood, hair and nails and increasing systolic and diastolic pressure levels, in line with previous epidemiologic findings, indicating a possible health concern for this highly exposed population. The possible relation between selenium over-exposure and onset of hypertension and other cardiovascular diseases deserves further investigation.