title: Differences of height and body mass index of youths in urban vs rural areas in Hunan province of China.
abstract: BACKGROUND
  Economic reforms in China were implemented approximately 30 years ago. Since then, people's nutrition, living conditions and overall health have continually improved, but there has been an imbalance between the progresses in urban vs rural areas. Height and body mass index (BMI) are regarded as two important indicators of nutritional status and overall health.
  
  
  OBJECTIVE
  The aim of this study was to investigate differences in height and BMI between Chinese youths of rural vs urban areas and further, to determine whether these differences have changed over time (1990s vs 2000s).
  
  
  METHODS
  24 194 urban youths and 7130 rural youths were recruited in Hunan province of China. In each gender group, the subjects were divided into eight subsets according to age, geographic area residence, and decade when the youths were measured. Independent t-tests were used to test the differences of height and BMI between the studied groups.
  
  
  RESULTS
  Both male and female youths from urban areas were significantly taller than youths from rural areas in both the 1990s and 2000s (all p<0.001), with the exception of the 1990s female 15-18 years subset (p=0.21). The height of youths was significantly greater in the 2000s compared to the corresponding gender and geographic subset in the 1990s (p<0.001), except for the female 15-18 years subset from rural areas (p=0.10). Similar results were obtained for BMI.
  
  
  CONCLUSIONS
  There are significant differences in height and BMI between youths raised in urban vs rural areas, and positive growth trends of height and BMI over time (1990s vs 2000s) in youths in Hunan Province of China.
authors.affiliation: Laboratory of Molecular and Statistical Genetics, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Fang
authors.initials: F
authors.lastname: Yang
authors.forename: Shu-Feng
authors.initials: SF
authors.lastname: Lei
authors.forename: Xiang-Li
authors.initials: XL
authors.lastname: Wang
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Papasian
authors.forename: Hong-Wen
authors.initials: HW
authors.lastname: Deng
mesh_terms: D000293:Adolescent; D001827:Body Height / Q000502:physiology*; D015992:Body Mass Index; D002648:Child; D002681:China; D005260:Female; D006801:Humans; D008297:Male; D012424:Rural Population; D012727:Sex Characteristics; D013997:Time Factors; D014505:Urban Population