title: Adiposity in relation to age at menarche and other reproductive factors among 300 000 Chinese women: findings from China Kadoorie Biobank study.
abstract: Adiposity is increasing rapidly in China but little is known about the relevance to it of women's reproductive factors, which differ inter-generationally and from that in the West. We assess associations of adiposity with life-course reproductive factors in Chinese women.
  
  
  
  In 2004-08, the nationwide China Kadoorie Biobank recruited 303 000 women aged 30-79 (mean 50) years from 10 diverse regions. Multivariable linear regression was used to examine associations of reproductive factors (e.g. age at menarche/first birth/menopause, parity, breastfeeding and reproductive years) with measures of general [e.g. body mass index (BMI)] and central [e.g. waist circumference (WC)] adiposity in adulthood.
  
  
  
  Overall, the mean BMI was 23.7 (standard deviation 3.3) kg/m 2 , mean age at menarche was 15 (2) years and nearly all had given birth (99%) and breastfed children (98%). Adiposity was associated inversely with age at menarche and at first birth, with 0.19 and 0.05 kg/m 2 lower BMI and 0.38 and 0.12 cm lower WC per 1-year delay respectively ( P  < 0.001). Among 128 259 post-menopausal women, adiposity was associated positively with age at menopause and reproductive years, with 0.05 and 0.07 kg/m 2 higher BMI and 0.12 and 0.17 cm higher WC per 1-year increase, respectively ( P  < 0.001). The proportion with overweight/obesity had similar associations with these reproductive factors. Adiposity had a non-linear positive association with parity, but no association with breastfeeding duration.
  
  
  
  Among Chinese women, earlier age at menarche and at first birth, later age at menopause and longer reproductive years were independently associated with increased adiposity late in life.
authors.affiliation: Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK.
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
authors.affiliation: Chinese Academy of Medical Sciences, Dong Cheng District, Beijing, China.|Department of Public Health, Beijing University, Beijing, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Li
authors.affiliation: Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK.
authors.forename: Iona Y
authors.initials: IY
authors.lastname: Millwood
authors.affiliation: Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Lewington
authors.affiliation: Chinese Academy of Medical Sciences, Dong Cheng District, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Sherliker
authors.affiliation: The George Institute for Global Health, University of Oxford, Oxford, UK.
authors.forename: Sanne Ae
authors.initials: SA
authors.lastname: Peters
authors.affiliation: Chinese Academy of Medical Sciences, Dong Cheng District, Beijing, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Bian
authors.affiliation: Sichuan CDC, Chengdu, Sichuan, China.
authors.forename: Xianping
authors.initials: X
authors.lastname: Wu
authors.affiliation: Zhejiang CDC, Hangzhou, Zhejiang, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yu
authors.affiliation: Hunan CDC NCDs Prevention and Control Department, Changsha, Hunan, China.
authors.forename: Huilin
authors.initials: H
authors.lastname: Liu
authors.affiliation: Hainan CDC NCDs Prevention and Control Department, Haikou, Hainan, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Maiji CDC, Tianshui, Gansu, China.
authors.forename: Enke
authors.initials: E
authors.lastname: Mao
authors.affiliation: The George Institute for Global Health, University of Sydney, Australia.
authors.forename: Junshi
authors.initials: J
authors.lastname: Chen
authors.affiliation: The George Institute for Global Health, University of Oxford, Oxford, UK.|The George Institute for Global Health, University of Sydney, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Woodward
authors.affiliation: Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Peto
authors.affiliation: Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), University of Oxford, Oxford, UK.
authors.forename: Zhengming
authors.initials: Z
authors.lastname: Chen
mesh_terms: D050154:Adiposity; D000328:Adult; D000368:Aged; D018070:Biological Specimen Banks; D015992:Body Mass Index; D001942:Breast Feeding / Q000706:statistics & numerical data; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008572:Menarche; D008593:Menopause; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000453:epidemiology*; D010298:Parity; D055105:Waist Circumference
keywords: Chinese; adiposity; cross-sectional studies; reproductive factors; women