: To analyze the prevalence of anemia and iron deficiency among primary and secondary school students in Rural Nutrition Improvement Program areas of Guizhou Province in 2023, and to explore the related factors, so as to provide evidence for Rural Nutrition Improvement Program optimization. Methods: In September 2023, a stratified random cluster sampling strategy was used to select 40 rural compulsory education schools with rural nutrition improvement program in five counties of Guizhou Province. School level questionnaire was employed to collect information of basic characteristics and school meal implementation. A total of 7 826 primary and secondary school students aged 6-16 underwent anthropometry and hemoglobin (Hb) determination; serum ferritin (SF) was additionally measured in a random subsample of 1 795 pupils. Students in Grade 3 and above also completed a questionnaire covering demographic characteristics, dietary behaviours and nutrition knowledge. Group comparisons were conducted by Chi square test or Fisher s exact test, and multivariable Logistic regression models were constructed to identify factors associated with anemia and iron deficiency. Results: The overall Hb level was (133.21±12.95)g/L, with an anemia prevalence of 7.17%. The overall SF level was (69.58±59.01)μg/L, with an iron deficiency prevalence of 2.73%. Multivariable analysis showed that stunting ( OR =1.88), school menus without nutrient calculation ( OR =1.61) and absence of menu planning software in the current semester ( OR =2.34) independently increased anemia risk, whereas obesity reduced it ( OR =0.54) (all P <0.05). Girls ( OR =4.16) and Grades 7-9 ( OR =5.93) increased iron deficiency risk (both P <0.05). Compared with rarely eating fresh vegetables, students with consuming <3 kinds per day ( OR =0.08) or exactly 3 kinds per day ( OR =0.06) had lower iron deficiency risks (both P <0.05). Conclusions Anemia and iron deficiency are prevalent among primary and secondary school students in Guizhou. Targeted intervention measures should be implemented for key populations to enhance the effectiveness of nutrition improvement program.

Objective:This paper analyzed the operation of network laboratory and external quality control assessment of endemic arsenic disease laboratories at all levels in Guizhou Province, to provide reliable experimental quality assurance for evaluating the prevention and treatment effect and taking targeted intervention measure of endemic arsenic poisoning.Methods:The results of network operation and external quality control (arsenic in water, arsenic in urine) were statistically analyzed from 2008 to 2017. The assessment scope included the arsenic detection laboratory of provincial (1), municipal (1) and county level (2) which undertook endemic arsenic poisoning monitoring tasks.Results:From 2008 to 2017, 1 provincial laboratory for the determination of arsenic in water and urine was qualified. From 2011 to 2017, 1 municipal laboratory for the determination of arsenic in water and urine was qualified. From 2014 to 2017, 2 county level laboratories for the determination of arsenic in water and urine were qualified. From 2014 to 2017, the water and urinary arsenic in provincial, municipal and county laboratories had been continuously assessed as all qualified. The │Z│ values of water arsenic in provincial laboratories from 2008 to 2017 and urine arsenic from 2009 to 2017 were ≤2, and the results were satisfactory. The │Z│ values of arsenic in water after 2010 and in urine after 2011 in municipal and one county level laboratories were ≤2, which were all qualified and the results were satisfactory.Conclusions:The network laboratory of endemic arsenic disease in Guizhou Province operates well. The quality control of the laboratory and the results of external quality control of arsenic samples meet the quality requirements of the national laboratory, which can provide accurate and reliable test data guarantee for the continuous elimination of endemic arsenic disease.

Objective: To explore the application of new pretreatment technology of automatic electrothermal digestion instrument in the detection of arsenic in urine samples, in order to achieve rapid, convenient and accurate detection results. Methods: Using wet digestion, an advanced sample preparation and digestion method (referred to as new pretreatment technology) was established by hydride generation-atomic fluorescence spectrometry (HG-AFS). Wet digestion: took 1.0 ml urine samples and put them into 10.0 ml corked scale digestive tubes, and added 0.20 ml sulfuric acid, 0.30 ml nitric acid and 0.50 ml hydrogen peroxide into the tubes successively. Shook solution and put them at AED-IV automatic electrothermal digestion instrument with 160 ℃ for half an hour, then heated up to 200 ℃ for 1 hour. It needed to be continually heated up to 260 ℃ and dissolved the solution until colorless transparent or light yellow. When the liquid level calm, and uniform reflux appeared, which meant the digestion finished, and then measured by atomic fluorescence photometer. At the same time, the new pretreatment technology was compared with the current standard (WS/T 474-2015) method, and the standard curve and linear range were calculated, as well as the detection line, precision and accuracy of the sample measurement. Results: The new pretreatment technology could digest 60 samples per sample, which was superior to the current standard methods (20 samples) and reduced the amount of reagent used. There was no statistically significant difference between the two methods (P > 0.05). In the linear range of 0-100 μg/L, the correlation coefficient (r) > 0.999 3, the detection limit of the method was 0.066 μg/L, and the relative standard deviation (RSD) < 5%. Conclusions The new pretreatment technology is fast, efficient, environmentally friendly, economical, highly automated. The experimental result error is in a controllable range. It can be used for digestion of arsenic content in urine of different concentrations and has high applicability.

Objective To apply hydride generation atomic fluorescence spectrophotometry (HG-AFS method) in urinary arsenic detection,and to provide a better,newer and more convenient detection method for quantitative analysis of urinary arsenic.Methods According to the Guide to Develop Biological Sample Inspection Method(WS/T 68-1996) and Guide for Establishing Occupational Health Standards-part 5:Determination Methods in Biological Materials (GB/T 210.5-2008),HG-AFS method was established to detect arsenic content in urine after modification of the method for sample pretreatment,and to verify the linear range of standard curve and linearity,detection limit,precision,accuracy,stability of the sample,and to compare the experimental results of HG-AFS method with those of standard methods of WS/T 28-1996 and Determination of Arsenic in Urine by Cyanide Generation Atomic Fluorescence Method (WS/T 474-2015).Results The HG-AFS method linear range was from 0-100 μg/L,the correlation coefficient r =0.999 9,the detection limit was 0.07 μg/L,the precision was 1.96％-3.97％,and the recovery rate was 95.1％-105.0％.There was no statistical significance between HG-AFS method,the standard of WS/T 28-1996 or WS/T 474-2015 methods (t =1.539,0.353,all P ＞ 0.05).Conclusion The new method is superior to the current detection method owing to its low detection limit,high precision,good accuracy,and wide linear range.