Affiliations: [a] Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR | [b] MRC Unit for Lifelong Health and Ageing, London, UK | [c] Elderly Health Services, Department of Health, The Government of HKSAR, Hong Kong SAR
Correspondence:
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Correspondence to: Linda C. W. Lam, Department of Psychiatry, The Chinese University of Hong Kong, G/F, Multi-centre, Tai Po Hospital, Tai Po, New Territories, Hong Kong SAR. Tel.: +852 26076026; Fax: +852 26671255; E-mail: cwlam@cuhk.edu.hk.
Abstract: Hypertension is a risk factor for dementia, but its exact role in contributing to dementia remains unknown. We conducted a community-based retrospective cohort study to examine the association of hypertension and widened pulse pressure (PP) with incident significant cognitive impairment (SCI) in Chinese older people in Hong Kong. A total of 1,925 subjects who were 65 years and older, ethnic Chinese, and community-living, with no history of cerebrovascular accidents or dementia, were recruited. Demographics, medical history, and physical parameters recorded at baseline were retrieved for analysis. Primary outcome was SCI developed in 6 years, which was defined by the presence of clinical dementia, scoring below the cutoff point on the Cantonese version of the Mini-Mental State Examination, and/or a global Clinical Dementia Rating of 1 to 3. Our data showed no difference in the point prevalence of pre-existing hypertension between subjects who remained cognitively stable and those who developed SCI (64.2% versus 65.8%; χ2 test, p = 0.68). However, subjects with incident SCI had a higher baseline PP (70 mmHg versus 66 mmHg; Mann-Whitney U-test, p = 0.03) and a decreasing trend in PP with time. Multiple logistic regression analysis showed that PP had a small but significant effect on the risk of SCI among the younger old subjects (OR = 1.02, p = 0.03). Our findings suggested that widened PP might be a risk factor for SCI among the younger old people. Further studies are needed to ascertain the association between hypertension and SCI in the Chinese older population and how widened PP contributes to SCI.
