title: Association of dietary consumption and serum levels of vitamin A and β-carotene with bone mineral density in Chinese adults.
abstract: BACKGROUND
  Former studies suggested an adverse effect of hypervitaminosis A on bone health, while the effects of retinol and its precursor (β-carotene) remain uncertain in populations consuming vitamin A (VA) mainly from plant sources.
  
  
  OBJECTIVE
  We investigated the association of serum, dietary retinol, and β-carotene with bone mineral density (BMD) in Chinese adults.
  
  
  METHODS
  We recruited 2101 women and 1053 men (aged 40-75 years) in Guangzhou, China. Dietary intake was assessed through face-to-face interviews with food-frequency questionnaires at baseline and 3 years later. Serum levels of retinol and β-carotene were determined by HPLC using a baseline specimen, and the BMD for the whole body (WB), lumbar spine (LS), total hip (TH), and femur neck (FN) were measured using dual energy X-ray absorptiometry at follow-up.
  
  
  RESULTS
  In general, greater levels of serum retinol, β-carotene, and the β-carotene-to-retinol ratio were associated with a higher BMD after adjustment for potential covariates in the total sample. BMD values in the top (vs. bottom) quartile were increased by 2.06% (TH) for retinol; 2.87% (WB), 2.51% (LS), 3.10% (FN) for β-carotene; 2.21% (WB) and 2.05% (FN) for the β-carotene-to-retinol ratio in the total sample (all p<0.05). A significant positive association with BMD was observed for dietary intake of β-carotene and total VA in retinol equivalents at the hip sites in the total sample.
  
  
  CONCLUSIONS
  Higher circulating and dietary levels of VA and β-carotene and higher serum β-carotene-to-retinol ratios were positively associated with BMD in Chinese adults consuming relatively low levels of VA, mainly from plant foods.
authors.affiliation: Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Geng-Dong
authors.initials: GD
authors.lastname: Chen
authors.affiliation: Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Zhu
authors.affiliation: Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Wen-Qi
authors.initials: WQ
authors.lastname: Shi
authors.affiliation: Division of Family Medicine and Primary Care, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Zhao-Min
authors.initials: ZM
authors.lastname: Liu
authors.affiliation: Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China. Electronic address: chenyum@mail.sysu.edu.cn.
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Chen
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D044466:Asian People; D015519:Bone Density / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D004032:Diet; D004034:Diet Surveys; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014801:Vitamin A / Q000097:blood*; D019207:beta Carotene / Q000097:blood*
chemical_list: D019207:beta Carotene; D014801:Vitamin A
keywords: Adults; Bone mineral density; Retinol; Serum; Vitamin A; β-Carotene