Abstract and Introduction
Abstract
Purpose Previous epidemiologic studies that focused on the association between open-angle glaucoma (OAG) and dementia showed inconsistent results. In the present study, we explored the association between OAG and dementia in an ethnic Chinese (ie, Taiwanese) population using a population-based data set.
Methods We retrieved data on study subjects for this case-control study from the Longitudinal Health Insurance Database 2000. We identified 7770 patients who had a diagnosis of dementia as cases, and 7770 subjects matched in terms of sex and age, which were randomly extracted as controls. A conditional logistic regression conditioned on age group, sex, and index year was used to assess the association of dementia with previously diagnosed OAG among the sampled patients.
Results Of 15 540 patients, 1.70% had prior OAG, including 2.02% of the dementia group and 1.38% of the controls. After adjusting for patient socioeconomic characteristics and comorbid medical disorders, dementia patients were more likely to have had prior OAG than controls (odds ratio (OR): 1.44; 95% confidence interval (CI): 1.12–1.85; P<0.01). In addition, female dementia patients were more likely to have had prior OAG than controls (OR: 1.93; 95% CI: 1.35–2.77; P<0.001), whereas no statistical difference in prior OAG between male dementia patients and controls was found.
Conclusions Female dementia patients were associated with a higher proportion of prior OAG than were the controls.
Introduction
As elderly populations have increased, dementia has become one of the major public health issues worldwide, and impacts of the illness will greatly expand in the future. Internationally, it is estimated that there were 36 million people with dementia in 2010 worldwide, and as the world population ages, the number is predicted to double every two decades. Dementia is usually caused by degenerative or vascular etiologies, and aging is recognized as one of the notable major risk factors.
Glaucoma is a progressive optic neuropathy pathologically characterized by the death of retinal ganglion cells and axon degeneration in the optic nerve, and clinically by abnormal optic disk cupping and visual field defects. Although elevated intraocular pressure (IOP) is recognized as one of the well-known risk factors for the development and progression of the disease, the pathogenesis of primary open-angle glaucoma (OAG) is still obscure and very intricate with interactions of age effects, genetic influences, and other risk factors. Because of similarities between primary OAG and Alzheimer's disease (AD) in animal experimental and human immunohistochemical studies, there is increasing evidence suggesting that OAG is a neurodegenerative disease of the eye.
However, previous epidemiologic studies focusing on the association between OAG and dementia showed inconsistent results. There are only four nationwide or population-based studies in Western countries, and, to the best of our knowledge, large epidemiologic investigations regarding the association between OAG and dementia are still lacking in Asian populations. Therefore, the aim of this study was to explore the association between OAG and dementia in an ethnic Chinese (ie, Taiwanese) population by means of a case-control design using a large, nationwide population-based data set in Taiwan.