title: Measurement of macular pigment optical density in a healthy Chinese population sample.
abstract: OBJECTIVE
  Macular pigment may protect against age-related macular degeneration (AMD) by its capacity to absorb blue light and scavenge free radicals. Current information on human macular pigment density has been largely from studies on Caucasian populations. The purpose of this study was to assess macular pigment density and its determinant factors in a Chinese population sample.
  
  
  METHODS
  Macular pigment optical density (MPOD) was measured in a healthy Chinese population using heterochromatic flicker photometry (HFP). Participants received a standard ophthalmic examination, and only subjects who were confirmed not to have any eye diseases except mild age-related cataract were included in the study. Demographic and lifestyle data and general health status were recorded by questionnaire.
  
  
  RESULTS
  A total of 281 unrelated healthy Chinese individuals, including 96 males and 185 females, with ages ranging from 17 to 85 years, participated in the study. The mean and standard deviation of MPOD levels were 0.56 ± 0.19, 0.49 ± 0.18, 0.36 ± 0.15, and 0.19 ± 0.12, respectively, at 0.25°, 0.5°, 1.0°, and 1.75° eccentricity points. A significant age-related decline in MPOD was observed at 0.25° (P = 0.014). Females tended to have relatively lower levels of MPOD than males at 0.25° (P = 0.21), 0.5° (P = 0.025), and 1.0° (P = 0.16). No statistically significant association of MPOD was observed with body mass index or smoking status.
  
  
  CONCLUSIONS
  Macular pigment density measured by HFP tended to decline with aging in this healthy Chinese population sample. Females may have lower levels of MPOD than males.
authors.affiliation: Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yu
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Johnson
authors.forename: Fu
authors.initials: F
authors.lastname: Shang
authors.forename: Apiradee
authors.initials: A
authors.lastname: Lim
authors.forename: Haiying
authors.initials: H
authors.lastname: Zhou
authors.forename: Lei
authors.initials: L
authors.lastname: Cui
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.forename: Torkel
authors.initials: T
authors.lastname: Snellingen
authors.forename: Xipu
authors.initials: X
authors.lastname: Liu
authors.forename: Ningli
authors.initials: N
authors.lastname: Wang
authors.forename: Ningpu
authors.initials: N
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D044466:Asian People; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D003720:Densitometry; D005260:Female; D015590:Fluorophotometry; D006801:Humans; D014975:Lutein / Q000032:analysis*; D008266:Macula Lutea / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D012168:Retinal Pigments / Q000032:analysis*; D017678:Sex Distribution; D011795:Surveys and Questionnaires; D014505:Urban Population / Q000706:statistics & numerical data; D024341:Xanthophylls / Q000032:analysis*; D055815:Young Adult; D065146:Zeaxanthins
chemical_list: D012168:Retinal Pigments; D024341:Xanthophylls; D065146:Zeaxanthins; D014975:Lutein