This cross-sectional biomonitoring study measured whole-blood germanium, zinc and lead by ICP-MS in 1,302 residents aged 6 to 60 years from three cities in Shandong Province, China. The overall geometric mean blood germanium was 19.9 µg/L, with no significant difference by sex. Blood germanium was associated in univariate tests with age group, alcohol use, hair dye use and the reported frequency of fried food consumption; the authors do not explain these associations.
Key numbers
- Whole-blood germanium, total population: geometric mean 19.9 µg/L (95% CI 19.3 to 20.6), median 18.3 µg/L, 5th to 95th percentile 5.10 to 45.2 µg/L, n = 1,302 (Table 2, p. 6).
- Men 19.8 µg/L versus women 20.2 µg/L (geometric means), p = 0.095 (Table 2, p. 6).
- Age group 16 to 20 years had the highest geometric mean, 29.3 µg/L (n = 168); ages 6 to 12 years had 16.2 µg/L (n = 231) and ages over 45 years 16.9 µg/L (n = 247) (Table 2, p. 6).
- Fried food every day: geometric mean 28.5 µg/L (n = 80), versus 20.9 µg/L at 1 to 2 times per week (n = 380) and 18.7 µg/L at 1 to 2 times per month (n = 842), p < 0.001 (Table 2, p. 6).
- Hair dye users 17.6 µg/L (n = 112) versus non-users 20.2 µg/L (n = 1,190) (Table 2, p. 6).
- Alcohol use: Table 2 gives 21.7 µg/L for drinkers (n = 192) and 19.6 µg/L for non-drinkers (n = 1,110); the running text on p. 6 prints these two values the other way round (Table 2 and text, p. 6).
- Limit of detection for blood germanium 0.18 µg/L after the tenfold dilution factor (pp. 3 to 4); all samples were above the detection limit (p. 4).
Methods (brief)
Cluster sampling selected one city from each of three socioeconomic levels (Qingdao, Jinan, Heze), with inclusion limited to residents of at least five years in areas without relevant industrial pollution and without recent trace-element supplements. Heparinized whole blood (0.5 mL) was diluted tenfold in Triton X-100 and nitric acid and analyzed by ICP-MS with yttrium as internal standard. Collection tubes and vials were pre-tested for contamination; spike recoveries across the three elements ranged from 90.0 to 112.4 percent. Group comparisons used Wilcoxon and Kruskal-Wallis tests on non-normal data.
Evidence fitness
The study supports a description of whole-blood germanium distributions in one Chinese provincial sample, including subgroup geometric means. It does not support dietary intake estimates, attribution to specific foods, or health thresholds: food was captured only as a questionnaire item on fried food frequency, no food or water was analyzed, and the associations are univariate. The authors describe germanium as an essential trace element in their introduction, but the paper presents no data on essentiality.
Limitations
Associations are unadjusted univariate comparisons and cannot separate age, diet and lifestyle. The paper reports no certified reference material for blood germanium. The alcohol subgroup values in the text are transposed relative to Table 2, and the alcohol p-value differs between the abstract (0.002) and Table 2 (0.001). The comparison values the authors quote for other populations are drawn from other studies and were not measured here.
Related evidence
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