Impact of current and past blood pressure on retinal arteriolar diameter in an older population

Objective To examine the effects of current and past blood pressure on retinal arteriolar diameter in a general older population. Design Cross-sectional and longitudinal studies. Setting Population-based cohort study of older residents from an area west of Sydney, Australia. Participants Two thousand three hundred and thirty-five individuals (n = 2335) (aged ⩾ 54 years) who attended the 5-year follow-up Blue Mountains Eye Study during 1997–99. Main outcome measures A computer-assisted method measured vessel diameters from digitized right eye retinal photographs. The narrowest quintile of central retinal arteriolar equivalent or arteriole-to-venule ratio (AVR) defined generalized arteriolar narrowing. Blood pressure was measured using a mercury sphygmomanometer. Results After simultaneous adjustment for age, sex, body mass index, smoking and current or past blood pressure, elevated levels of both current and past blood pressure were associated with narrower retinal arterioles [Ptrend = 0.009 and 0.007 for current and past systolic blood pressure (SBP), respectively] and lower AVR [Ptrend = 0.001 and 0.0009 for current and past diastolic blood pressure (DBP), respectively]. Generalized arteriolar narrowing was associated with both current blood pressure [adjusted odds ratio (OR) 2.4, 95% confidence interval (CI) 1.5–3.8 for the highest versus lowest quintile of current DBP] and past blood pressure (adjusted OR 1.7, 95% CI 1.1–2.6, for the highest versus lowest quintile of past DBP). Hypertension duration or control status at baseline had no additional effect on arteriolar diameter after adjusting for current blood pressure. Conclusions Our data document the independent effects of both current and past blood pressure on small vessel calibre in the retina, suggesting that retinal arteriolar narrowing may result from the cumulative effects of long-standing hypertension.