title: Main source of drinking water and familial aggregation of Kashin-Beck disease: a population based on case-control family study.
abstract: OBJECTIVE
  Kashin-Beck disease (KBD) is an osteoarthropathy affecting 2.5 million of 30 million residents of China's KBD-endemic regions. This study assesses the etiologic role of river water as a main source of drinking water, its impact on and interaction with KBD familial aggregation.
  
  
  METHODS
  From 2006-2007, we conducted a population-based case-control study of familial KBD in Linyou County, Shaanxi Province, China. Study subjects included 212 case families (1,951 individuals) and 212 control families (1,897 individuals). Using conditional logistic regression to analyze case-control data and second-order generalized estimating equation (GEE2) to examine family data, we adjusted for age and gender in all marginal regression analyses.
  
  
  RESULTS
  The odds ratio (OR) for river water intake's association with KBD was 5.97 (95% confidence interval [CI]), 3.32-10.72). Compared with relatives of controls, proband relatives had a higher risk of disease, with a conditional OR = 2.35 (95% CI, 1.05-5.24). When river water was controlled in the analyses, association parameters among first- and second-degree relatives were no longer statistically significant.
  
  
  CONCLUSIONS
  Collective river water intake among relatives was likely and predominantly responsible for familial KBD aggregation in southwestern China.
authors: Institute of Endemic Diseases, Xi'an Jiaotong University, School of Medicine, Xi'an, Shaanxi, China.
authors: Yongzhong
authors: Y
authors: Zhang
authors: Xiong
authors: X
authors: Guo
authors: Zhiguang
authors: Z
authors: Ping
authors: Min
authors: M
authors: Yu
authors: Xiaowei
authors: X
authors: Shi
authors: Aili
authors: A
authors: Lv
authors: Fuqi
authors: F
authors: Wang
authors: Zhiwen
authors: Z
authors: Wang
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000209:etiology*; D045483:Rivers; D014881:Water Supply