Cluster analysis of 2007 survey data of current status of the national brick-tea-born fluorosis

Objective Cluster analysis method was applied to analyze the data of brick-tea-born fluorosis,to clarify the provincial and municipal classification hierarchy in nation-wide epidemic areas and to guide the prophylaxis and treatment of the disease.Methods Prevalence survey database of the 2007 national brick-tea-born fluorosis was analyzed.Detection rate of second degree and above clinical skeletal fluorosis as clustered index,clustering analysis of all survey data was carried out,clustering figure was drawn,and analysis of variance and multiple comparison was done.Results The provincial level of the nation-wide epidemic areas of the brick-teaborn fluorosis could be classified into three categories:the first category including Tibet and Sichuan province,the second category including Qinghai province,and the third including Inner Mongolia,Gansu,Xinjiang and Ningxia provinces; The city-level they were also could be classified into three categories:the first category including Aba,Shigatse region and Lhasa,the second including Wulanchabu,Hulun Buir,Baotou,Qinghai state,Guoluo state,Haixi state,Xining city,Haidong state,Ganzi state,Longnan city,Jiuquan city,Urumqi city and the state of Bortala,and the other cities were the third category cities.The differences of clinical skeletal fluorosis detection rate between the first,second,and third provincial and municipal categories(35.18％,16.21％,5.22％,41.16％,19.64％,4.19％) were statistically significant (all P ＜ 0.05).Conclusions Brick-tea-born fluorosis can be classified by using cluster analysis at the provincial and municipal levels.Cluster analysis results can provide a scientific basis for effective implementation of the prophylaxis and treatment of brick-tea-born fluorosis. Key words: Tea; Fluorosis,dental; Osteofluorosis; Cluster analysis; Data collection