Effects of firsthand tobacco smoking on retinal vessel caliber: a systematic review and meta-analysis

PURPOSE

To review the effects of firsthand tobacco smoking on central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) of firsthand tobacco smokers.

METHODS

We performed a search on EMBASE and PubMed for studies up to 15th July 2022. Two independent reviewers selected studies with baseline data of CRAE and CRVE of current smokers, nonsmokers, and former smokers. Initial search identified 893 studies, of which 10 were included in the meta-analysis. Two independent reviewers extracted data from the included studies. The quality of studies was assessed by the Newcastle-Ottawa Scale.

RESULTS

In this meta-analysis, 7431 nonsmokers, 2448 current smokers and 5786 former smokers, as well as 7404 nonsmokers, 2430 current smokers and 5763 former smokers were included in CRAE and CRVE analysis respectively. Nonsmokers had narrower CRVE (Weighted mean difference [WMD], -12.15; 95% CI, -17.33 - -6.96) and CRAE (WMD, -4.77; 95% CI, -7.96 - -1.57) than current smokers, and narrower CRVE (WMD, -3.08; 95% CI, -6.06 - -0.11) than former smokers. Current smokers had wider CRVE (WMD, 10.42; 95% CI, 7.80 - 13.04) and CRAE (WMD, 7.05; 95% CI, 6.65 - 7.46) than former smokers. Subgroup analysis and sensitivity analysis were performed.

CONCLUSION

Firsthand tobacco smoking resulted in wider CRAE and CRVE in current and former smokers, particularly in CRVE, and such changes may not be reversible after smoking cessation. Therefore, retinal vessel caliber may reflect the effects of firsthand tobacco smoking and be used to estimate the risk of cardiovascular diseases.

Retinal vessel caliber and caliber responses in true normotensive black and white adults: The African-PREDICT study

PURPOSE

Globally, a detrimental shift in cardiovascular disease risk factors and a higher mortality level are reported in some black populations. The retinal microvasculature provides early insight into the pathogenesis of systemic vascular diseases, but it is unclear whether retinal vessel calibers and acute retinal vessel functional responses differ between young healthy black and white adults.

METHODS

We included 112 black and 143 white healthy normotensive adults (20-30 years). Retinal vessel calibers (central retinal artery and vein equivalent (CRAE and CRVE)) were calculated from retinal images and vessel caliber responses to flicker light induced provocation (FLIP) were determined. Additionally, ambulatory blood pressure (BP), anthropometry and blood samples were collected.

RESULTS

The groups displayed similar 24 h BP profiles and anthropometry (all p > .24). Black participants demonstrated a smaller CRAE (158 ± 11 vs. 164 ± 11 MU, p < .001) compared to the white group, whereas CRVE was similar (p = .57). In response to FLIP, artery maximal dilation was greater in the black vs. white group (5.6 ± 2.1 vs. 3.3 ± 1.8%; p < .001).

CONCLUSIONS

Already at a young age, healthy black adults showed narrower retinal arteries relative to the white population. Follow-up studies are underway to show if this will be related to increased risk for hypertension development. The reason for the larger vessel dilation responses to FLIP in the black population is unclear and warrants further investigation.

Increasing fruit and vegetable intake has no effect on retinal vessel caliber in adults at high risk of developing cardiovascular disease

BACKGROUND AND AIM

Retinal vessel abnormalities are associated with cardiovascular disease (CVD) risk. To date, there are no trials investigating the effect of dietary factors on the retinal microvasculature. This study examined the dose response effect of fruit and vegetable (FV) intake on retinal vessel caliber in overweight adults at high CVD risk.

METHODS AND RESULTS

Following a 4 week washout period, participants were randomized to consume either 2 or 4 or 7 portions of FV daily for 12 weeks. Retinal vessel caliber was measured at baseline and post-intervention. A total of 62 participants completed the study. Self-reported FV intake indicated good compliance with the intervention, with serum concentrations of zeaxanthin and lutein increasing significantly across the groups in a dose-dependent manner (P for trend < 0.05). There were no significant changes in body composition, 24-h ambulatory blood pressure or fasting blood lipid profiles in response to the FV intervention. Increasing age was a significant determinant of wider retinal venules (P = 0.004) whereas baseline systolic blood pressure was a significant determinant of narrower retinal arterioles (P = 0.03). Overall, there was no evidence of any short-term dose-response effect of FV intake on retinal vessel caliber (CRAE (P = 0.92) or CRVE (P = 0.42)).

CONCLUSIONS

This study demonstrated no effect of increasing FV intake on retinal vessel caliber in overweight adults at high risk of developing primary CVD.

CLINICAL TRIAL REGISTRATION

NCT00874341.

Associations between retinal microvascular structure and the severity and extent of coronary artery disease

OBJECTIVE

Microvascular mechanisms are increasingly recognized as being involved in a significant proportion of coronary artery disease (CAD) cases, but their exact contribution or role is unclear. We aimed to define the association between retinal microvascular signs and both CAD extent and severity.

METHODS

1120 participants of the Australian Heart Eye Study were included. Retinal vessel caliber was measured from digital retinal images. Extent and severity of CAD was assessed using several approaches. First, a simple scoring classifying participants as having one-vessel, two-vessel, and three-vessel disease was used. Gensini and Extent scores were calculated using angiography findings.

RESULTS

After multivariable adjustment, significantly narrower retinal arteriolar caliber in women (comparing lowest versus highest quartile or reference) and wider venular caliber in men (comparing highest versus lowest quartile or reference) were associated with 2-fold and 54% higher odds of having at least one stenosis ≥50% in the epicardial coronary arteries, respectively. Women in the third versus first tertile of retinal venular caliber had 92% and ∼2-fold higher likelihood of having higher Gensini and Extent scores, respectively. Women in the lowest versus highest tertile of retinal arteriolar caliber had greater odds of having higher Extent scores, OR 2.99 (95% CI 1.45-6.16). In men, non-significant associations were observed between retinal vascular caliber and Gensini and Extent scores.

CONCLUSIONS

An unhealthy retinal microvascular profile, namely, narrower retinal arterioles and wider venules was associated with more diffuse and severe CAD among women.

Is retinal vasculature change associated with risk of obesity? Longitudinal cohort study in Japanese adults: The Funagata study

Aims/Introduction:  To examine the association between baseline retinal vessel caliber change and prevalence, and 5-year incidence of obesity in the adult Japanese population of the Funagata study.

MATERIALS AND METHODS

  Of 900 individuals (age ≥ 35 years) who underwent systemic and retinal examinations in the Funagata study during 2000-2002, 584 (64.8%) were not obese as defined by body mass index (BMI) ≥ 25 kg/m(2), and considered at risk of incident obesity. In 2005-2007, 454 patients returned for 5-year follow-up examination (52.9%). Incidence of overweight was defined as subjects who were not overweight at baseline examination (BMI < 23 kg/m(2)), but overweight (BMI ≥ 23 to <25 kg/m(2)) at follow up, and that of obesity as subjects who were not obese at baseline examination (BMI < 25 kg/m(2)), but obese (BMI ≥ 25 kg/m(2)) at follow up.

RESULTS

  The prevalence of obesity at baseline was 35.1% (316/900); there was a cross-sectional association between wider retinal venular diameters and obesity (adjusted odds ratio [OR] per +1 standard deviation (SD) change: 1.18; 95% confidence interval [CI]: 1.02-1.35) after adjusting for age and sex. Cumulative incidence of obesity between baseline and 5-year follow up was 10.6% (32/303). Although the risk of incident overweight or obesity was higher in persons with wider retinal venular caliber, there were no statistically significant associations between baseline venular caliber and 5-year incidence of obesity.

CONCLUSIONS

  Although we found significant cross-sectional associations of retinal venodilation with the prevalence of overweight, we could not confirm that retinal venodilation preceded the development of obesity in this population. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.00086.x, 2011).