Is It the Appropriate Time to Stop Applying Selenium Enriched Salt in Kashin-Beck Disease Areas in China?

We aimed to identify significant factors of selenium (Se) nutrition of children in Kashin-Beck disease (KBD) endemic areas and non-KBD area in Shaanxi Province for providing evidence of whether it is the time to stop applying Se-enriched salt in KBD areas. A cross-sectional study contained 368 stratified randomly selected children aged 4-14 years was conducted with 24-h retrospective questionnaire based on a pre-investigation. Food and hair samples were collected and had Se contents determined with hydride generation atomic fluorescence spectrometry. Average hair Se content of 349.0 +/- 60.2 ng/g in KBD-endemic counties was significantly lower than 374.1 +/- 47.0 ng/g in non-KBD counties. It was significantly higher in the male children (365.2 +/- 52.3 ng/g) than in the female (345.0 +/- 62.2 ng/g, p = 0.002) and significantly higher in the 4.0-6.9 years group (375.2 +/- 58.9 ng/g) than the 7.0-14.0 years group (347.0 +/- 56.1 ng/g, p < 0.01). Gender, living area, Se intake without supplements, Se-enriched salt, oil source and protein intake were identified as significant factors of hair Se contents. Cereals, meat and milk were commonly included as significant food categories that mainly contributed to Se intake without supplement of the whole population. Balanced dietary structure without Se supplement could effectively enhance and maintain children's Se nutrition. It may be the time to stop applying Se-enriched salt in KBD areas in Shaanxi Province.