Recent studies have found an association between exposure to Chlamydia pneumoniae infection and risk of age-related macular degeneration (AMD). To assess a potential risk of AMD progression posed by exposure to C. pneumoniae, the authors reexamined Australian residents in 2001-2002 who were aged 51-89 years with early AMD at baseline (1992-1995). Examination included macular photography and an enzyme-linked immunosorbent assay to determine antibody titers to the elementary bodies from C. pneumoniae AR39. AMD progression was assessed quantitatively, using both coarse and fine progression steps following an international classification for AMD grading, and also qualitatively, by side-by-side comparison of baseline and follow-up macular photographs. Serologic data were available for 246 of 254 (97%) subjects. AMD progression was associated with a higher antibody titer. After adjustment for age, smoking, family history of AMD, history of cardiovascular diseases, and source study, the subjects in the upper tertiles of antibody titers were 2.1 (95% confidence interval: 0.92,4.69), 2.6 (95% confidence interval: 1.24, 5.41), and 3.0 (95% confidence interval: 1.46, 6.37) times more at risk of progression than those in the lowest tertile, using three definitions of progression, respectively. The fact that seroreactivity to C. pneumoniae was independently associated with the risk of AMD progression suggests that C. pneumoniae infection may be an additional risk factor for AMD progression.
Bibliographical noteFunding Information:
The Cardiovascular Health and Age-related Maculopathy Study was supported by National Health and Medical Research Council grant 128201. Serologic tests were conducted in the United States and supported by Public Health Service grant AI 42790 from the National Institutes of Health. Additional support was provided by Perpetual Trustees Australia, Ltd. (Ramaciotti Foundation), ANZ Executors & Trustee Company, Ltd. (The Hugh D. T. Williamson Foundation under the Medical Research and Technology in Victoria Program), the Royal Victorian Institute for the Blind, the Royal Victorian Eye & Ear Hospital Research Committee, the Lions Club of Victoria, and the Australian Institute of Health and Welfare. The authors declare no conflict of interest.
- Chlamydophila pneumoniae
- Disease progression
- Macular degeneration