This Chinese follow-up study measured urinary selenium and zinc each year from 2017 to 2019 in children with and without Kashin-Beck disease in six endemic Shaanxi counties. Urinary zinc did not differ between children with the disease and controls. It varied between years and counties.
Key numbers
- Mean urinary zinc, all subjects: 0.36 ± 0.24 mg/L (2017), 0.39 mg/L (2018), 0.31 mg/L (2019) (Table 2, p. 4; Results, p. 6).
- Disease vs control children: 0.38 ± 0.30 vs 0.35 ± 0.22 mg/L (2017), 0.41 ± 0.38 vs 0.39 ± 0.28 (2018), 0.43 ± 0.39 vs 0.28 ± 0.20 (2019), none significant (Table 2, p. 4).
- 424 urine and 137 hair samples were collected over the three years (Abstract, p. 1).
Methods (brief)
Mid-stream urine was collected each year; zinc was measured in triplicate by atomic absorption spectrophotometry (Agilent DUO240) with national reference materials. Generalized estimating equations assessed factors related to selenium.
Evidence fitness
The study gives repeated urinary zinc values in a rural child population and supports the conclusion that urinary zinc did not distinguish Kashin-Beck disease cases. Urinary zinc is a spot excretion measure and not a dietary intake estimate.
Limitations
Spot urine without creatinine correction is reported. Small case group (30). The paper focuses on selenium; zinc analysis is secondary.
Related evidence
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