RESUMEN
Selenium (Se) is an essential nutrient element for human health, and middle-aged and elderly people (age ≥ 45 years old) are at higher risk of nutrient deficiency including Se due to their physiological characteristics. This study investigated the hair Se content of middle-aged and elderly people in China with the purpose of providing a reference for prescription of hair Se normal range in this population. In this study, the hair Se content of 2155 middle-aged and elderly people was detected with atomic fluorescence photometry. The participants were recruited from 15 provinces or municipalities spreading from south to north of China with a diverse Se content in soil. Additionally, the relationships between hair Se content with sex, age, and BMI were analyzed. The results found that the median and 95% quantile of hair Se content were 0.36 µg/g and 0.60 µg/g respectively, with a range of 0.08 to 20.04 µg/g in middle-aged and elderly Chinese. The hair Se content mostly concentrated at 0.23~0.48 µg/g in 81.11% of participants. The participants in Guangdong and Hunan provinces had the highest hair Se levels (medians were 0.51 and 0.50 µg/g, respectively), while Henan and Shaanxi provinces had the lowest levels (medians were 0.30 and 0.29 µg/g, respectively). In addition, the Se content of males was higher than that of females (p < 0.05), whereas there was no significant difference between different ages and BMI (p > 0.05). In conclusion, this study found that the hair Se content of middle-aged and elderly Chinese ranges from 0.08 to 20.04 µg/g, with median and 95% quantile of 0.36 µg/g and 0.60 µg/g, respectively. Our results provide a reference for the establishment of hair Se content in this population and suggest that the differences of region and sex should be considered when setting up the range.