title: Age-Related Changes of Intraocular Pressure in Elderly People in Southern China: Lingtou Eye Cohort Study.
abstract: OBJECTIVE
  To study age-related changes of intraocular pressure (IOP) and assess the cohort effect in both cross-sectional and longitudinal settings among elderly Chinese adults.
  
  
  METHODS
  Participants were enrolled from the Lingtou Eye Cohort Study with Chinese government officials aged 40 years and older at baseline and received physical check-up and ocular examinations from 2010 to 2012. IOP was measured using a non-contact tonometer according to standardized protocols, as well as systolic blood pressure (SBP), diastolic blood pressure (DBP) and body mass index (BMI). Participants who had attended IOP measurements in both 2010 and 2012 were included in this study. Cross-sectional association of IOP with age was assessed using multivariate liner regression analyses and based on the data of 2010. Longitudinal changes in IOP were assessed by paired t-test.
  
  
  RESULTS
  A total of 3372 subjects were enrolled in the current analysis (2010 mean [SD] age, 61.9 [7.1] years; 60.2% men). The mean IOP in 2010 was 15.4 ± 2.3 mmHg for women and 15.2 ± 2.3 mmHg for men with an intersex difference (P = 0.029). Cross-sectional analysis showed that IOP was negatively associated with age (P = 0.003, β = -0.033 for women and P<0.001, β = -0.061 for men) adjusted for baseline SBP, DBP and BMI. Paired t-test suggested that IOP was higher in the year 2012 than 2010 in women (P = 0.006) but did not change significantly in men within 2 years (P = 0.345). In addition, the 2-year changes of IOP were not associated with age adjusted for baseline IOP in 2010 (P = 0.249).
  
  
  CONCLUSIONS
  Cross-sectional data suggests that IOP is lower in people with older age. Longitudinal data does not support such findings and thus the identified decreasing pattern with age in cross-sectional analysis is likely caused by cohort effects.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Xiaotong
authors.initials: X
authors.lastname: Han
authors.affiliation: Guangzhou No.11 People's Hospital, Guangzhou, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Niu
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Xinxing
authors.initials: X
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia.
authors.forename: William
authors.initials: W
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.|Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia.
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D014065:Tonometry, Ocular