ABSTRACT
Objective To observe the effects of comprehensive measures of changing grain,selenium supplementation,off-site education and resettlement on prevention of children's Kashin-Beck disease in Aba state.Methods Fifty eight villages in Aba Kashin-Beck disease areas were chosen as intervention points in Aba state Sichuan province from 2007 to 2011.Based on the implementation of prevention and control measures,the villages were divided into off-site education + changing grain + selenium supplementation group and resettlement + off-site education + changing grain + selenium supplementation group,Geletuo town of Seda county,Ganzi state was selected as a control point,and right-hand anteroposterior X-ray examination(including the wrist) was carried out on children aged 6-13 from 2007 to 2011 annually.Clinical and X-ray diagnosis of Kashin-Beck disease was made in accordance with the Diagnostic Criteria of Kaschin-Beck Disease(GB 16003-1995).The effects of prevention and control measures were evaluated by comparing the child X-ray detection rate before and after the implementation of the measures.Results The average X-ray positive detectable rate of children in the intervention points was 2.07％(66/3181),2.72％ (69/2540),1.16％ (35/3017),0.56％ (19/3397) and 0.56％ (24/4273),respectively from 2007 to 2011,with a downward trend (x2trend =66.74,P ＜ 0.01).There was a downward trend in the average X-ray positive detectable rate of children in off-site education + changing grain + selenium supplementation group [1.60％(29/1809),2.63％ (39/1484),1.29％ (25/1941),0.64％ (15/2332),0.42％ (10/2379)] and resettlement + off-site education + changing grain + selenium supplementation group [2.70％ (37/1372),2.84％ (30/1056),0.93％(10/1076),0.38％ (4/1065),0.74％(14/1894)] (x2trend=30.97,35.19,all P ＜ 0.01).The average X-ray positive detectable rate of children in the intervention group was 0 from 2007 to 2010,and was 1.61％ (1/62) in 2011.The difference of X-ray positive detectable rate was not statistically significant in the control group in the 5 years from 2007 to 2011.The difference of children's X-ray positive detectable rate was not statistically significant between control group and intervention group.Conclusions The effect of taking changing grain,selenium supplementation,off-site education and resettlement comprehensive measures to prevent children's Kashin-Beck disease is not significant in those places where the state of Kaschin-Beck disease is not active.
ABSTRACT
<p><b>OBJECTIVE</b>To discuss application of structural equation model (SEM) approach in epidemiological research.</p><p><b>METHODS</b>A brief overview on major components of SEM, statistical assumptions underlying the use of SEM, and current software available to users and how SEM can be used were discussed through a practical epidemiological research project.</p><p><b>RESULTS</b>Advantages of SEM comparing with conventional epidemiological approach were shown. SEM, having the nature of comprehensive thinking and analytic approach, not only exploring the association between factors and diseases but also among factors. It also served a confirmatory, rather than exploratory approach on data modeling, as well as having the capability of correcting estimates by separating measurement error from the equations, to provide modeling the latent variables.</p><p><b>CONCLUSION</b>SEM approach could be used in epidemiological research as having some advantages comparing with conventional epidemiological approaches.</p>