Effect of blood pressure on the retinal vasculature in a multi-ethnic Asian population

Abstract

Blood pressure has a significant effect on retinal arterioles. There are few data on whether this effect varies by race/ethnicity. We examined the relationship of blood pressure and retinal vascular caliber in a multi-ethnic Asian population. The study is population-based and cross sectional in design. A total of 3749 Chinese, Malay and Indian participants aged X24 years residing in Singapore were included in the study. Retinal vascular caliber was measured using a computer program from digital retinal photographs. The associations of retinal vascular caliber with blood pressure and hypertension in each racial/ethnic group were analyzed. The main outcome measures are retinal arteriolar caliber and venular caliber. The results show that retinal arterioles were narrower in persons with uncontrolled/untreated hypertension (140.0 lm) as compared with persons with controlled hypertension (142.1 lm, P¼0.0001) and those with no hypertension (146.0 lm, Po0.0001). On controlling for age, gender, body mass index, lipids and smoking, each 10 mm Hg increase in mean arterial blood pressure was associated with a 3.1 lm decrease in arteriolar caliber (Po0.0001), with a similar magnitude seen in all three racial/ethnic groups: 3.1 lm in Chinese, 2.8 lm in Malays and 3.2 lm in Indians (Po0.0001 for all). Each 10 mm Hg increase in mean arterial blood pressure was associated with a 1.8 lm increase in venular caliber (Po0.0001); furthermore, the magnitude of this effect was similar across the three racial/ethnic groups. The effect of blood pressure on the retinal vasculature was similar across three major racial/ethnic groups in Asia.

Microcirculatory Rarefaction in South Asians — A Potential Mechanism for Increased Cardiovascular Risk and Diabetes

“…Owen et al [29] found no difference in tortuosity between European, South Asians and African Caribbean children but did not examine vessel diameter. Jaganathan et al [30] have reported comparisons of central retinal arteriolar and venular equivalents between Malay-, Chinese- and Indian-origin people in Singapore and, as in our study, they found that elevated blood pressure was associated with arteriolar narrowing in all ethnic groups. The authors also reported that retinal arteriolar calibre was wider in people of Malay ethnicity, while Chinese and Indian people did not differ.…”

Obesity and the Microvasculature: A Systematic Review and Meta-Analysis

“…Sample sizes ranged from 797 [23] to 10,778 [26], for a total of 38,979 adults and 5,204 children. Study participants were from diverse countries including USA [7], [22]–[23], [26], [30], Australia [9], [25], [27], Singapore [24], [28]–[29] and The Netherlands [16] (Table 1). Mean BMI was 25.0 kg/m 2 or higher in seven adult studies [7], [16], [22], [26]–[27], [29]–[30] In four studies [7], [27], [29]–[30] more than one-half of participants had hypertension and one study was conducted in people with type 2 diabetes [7] (Table S2).…”

“…Third, there is potential measurement bias due to different photographic procedures and software used in measuring retinal vascular caliber, resulting in possible overestimation or underestimation of the true association between BMI and retinal vascular calibers. Fourth, we standardized BMI categories according to the WHO classification for Caucasians whereas three studies were conducted in Asians [24], [28]–[29]. Also, both unmeasured and residual confounding, e.g.…”

Quantitative and qualitative retinal microvascular characteristics and blood pressure

“…New digital retinal photography and image processing technologies developed for quantitative objective measurements now provide information on the association of blood pressure with retinal microvascular characteristics [35]. Previous studies showed that narrower retinal arterioles are strongly associated with elevated blood pressure levels and the development of hypertension, and that retinal arteriolar narrowing may precede clinical hypertension [36][37][38][39][40][41][42][43][44][45][46][47]. Furthermore, retinal arteriolar narrowing has been linked to several hypertension genes, suggesting that it may also contribute to the pathogenesis of hypertension [48].…”