Body fat evolution as predictor of retinal microvasculature in children

Association of childhood obesity on retinal microvasculature and the role of biochemical markers for its early detection

BACKGROUND

Childhood obesity is a growing public health concern, associated with several systemic disorders including changes in retinal microvasculature. This study aims to assess the relationship between body composition, biochemical markers, and retinal microvascular changes in obese children.

METHODS

In this cross-sectional study, 45 overweight and obese children and 46 age- and sex-matched healthy individuals were evaluated. In addition to physical examination, anthropometric measurements were obtained using a body composition analyzer. A comprehensive ophthalmic assessment was conducted for all participants, which included advanced optical biometry, autorefractometry, visual acuity testing, and slit-lamp examination. Retinal microvasculature was assessed using optical coherence tomography angiography (OCT-A). Biochemical markers, including lipid profile, liver function tests, and CRP (as marker of inflammation), were also analyzed.

RESULTS

The mean ages were 10.18 and 9.40 years in the obese/overweight and normal weight groups, respectively. Increased foveal thickness (p = 0.04) and foveal vessel density (p = 0.01) in the superficial capillary plexus, and decreased vessel density in the inferior parafoveal region of the deep capillary plexus (p = 0.03) were observed in obese/overweight children. Adjusted and crude regression analysis showed significant associations between body mass index, percent body fat, fasting blood glucose, and serum alanine transaminase levels with foveal vessel density, as well as between body mass index and serum triglycerides levels with foveal thickness.

CONCLUSIONS

Our findings suggest that childhood obesity is associated with significant alterations in retinal microvasculature. We propose that retinal health assessments and biochemical evaluations be considered in the clinical management of obese children.

Systematic review on retinal microvasculature, physical activity, sedentary behaviour and adiposity in children and adolescents

AIM

As retinal microvasculature (RMV) can be assessed non-invasively, it presents an opportunity to examine the health and disease of the human microcirculation, as RMV alterations have been recognised as one of the earliest signs of cardiovascular risk. This review summarises current literature on the associations between physical activity (PA), sedentary behaviour (SB) and/or adiposity and RMV in children and adolescents aged 0-18 years.

METHODS

Six databases were searched (MEDLINE, Scopus, Web of Science, ScienceDirect, PsycINFO and CINAHL), through to December 11, 2019. English, Portuguese, French, Spanish or Dutch were the languages searched. Meta-analyses were performed using the meta-analyst software.

RESULTS

A total of 6796 studies were screened, and 26 studies were included, representing 24 448 participants, from 12 different countries. Studies reporting results on weight status were twenty-three, PA was assessed in six studies, and SB was assessed in three studies. Four studies examined weight status and PA/SB. Meta-analysis was performed for two studies and showed that children with obesity have smaller retinal arterioles (-2.38 µm difference, 95% CI 0.62, 4.15 µm) and larger retinal venules (2.74 µm difference, 95% CI -4.78, -0.72 µm) than children without obesity.

CONCLUSION

Results showed that adiposity was associated with microvascular alterations in children and adolescents. Increased adiposity, lack of PA and high levels of SB were negatively correlated with vessel width parameters.

Effects of a cluster-randomized school-based prevention program on physical activity and microvascular function (JuvenTUM 3)

BACKGROUND AND AIMS

It is unknown whether a school-based prevention program has the potential to improve microvascular health in children. This study investigates the impact of the school-based lifestyle intervention program JuvenTUM 3 on physical activity, physical fitness, serum biomarkers and microvascular function.

METHODS

We studied 434 children (10-11 years) in a cluster-randomized setting (8 intervention schools, IG; 7 control schools, CG) over 18 months. The school-based prevention program included weekly lifestyle lessons for children with the aim to increase physical activity in and outside of school, physical fitness as well as health behavior. Anthropometric measurements and blood sampling were conducted using standard protocols, physical activity by use of a questionnaire and physical fitness by a 6-item-test battery. Central retinal arteriolar (CRAE) and venular (CRVE) vessel diameters as early marker of vascular dysfunction, as well as the arteriolar-to-venular diameter ratio (AVR), were investigated with a non-mydriatic vessel analyser.

RESULTS

School-based physical activity increased in 41% of children in IG (19% in CG, p = 0.038). Improvements in vascular parameters were observed for AVR (increase in 83% of children in IG versus 50% in CG; p < 0.001) and for CRVE (43% of children with retinal venular widening in IG versus 58% in CG, p = 0.019). These vascular improvements were also seen in overweight children for CRAE (p = 0.021) and AVR (p < 0.001).

CONCLUSIONS

The school-based prevention program JuvenTUM 3 increased physical activity at school inducing favourable effects on retinal microvasculature function. These findings underline the importance of early lifestyle interventions in children for primary prevention of cardiovascular disease.

Obesity, Blood Pressure, and Retinal Vessels: A Meta-analysis

CONTEXT

Retinal vessel imaging is a noninvasive diagnostic tool used to evaluate cardiovascular risk. Childhood obesity and elevated blood pressure (BP) are associated with retinal microvascular alterations.

OBJECTIVE

To systematically review and meta-analyze associations between obesity, BP, and physical activity with retinal vessel diameters in children.

DATA SOURCES

We conducted a literature search through the databases of PubMed, Embase, Ovid, Web of Science, and the Cochrane Register of Controlled Trials.

STUDY SELECTION

School- and population-based cross-sectional data.

DATA EXTRACTION

General information, study design, participants, exposure, and outcomes.

RESULTS

A total of 1751 studies were found, and 30 full-text articles were analyzed for eligibility. Twenty-two articles (18 865 children and adolescents) were used for further assessment and reflection. Eleven articles were finally included in the meta-analysis. We found that a higher BMI is associated with narrower retinal arteriolar (pooled estimate effect size -0.37 [95% confidence interval (CI): -0.50 to -0.24]) and wider venular diameters (0.35 [95% CI: 0.07 to 0.63]). Systolic and diastolic BP are associated with retinal arteriolar narrowing (systolic BP: -0.63 [95% CI: -0.92 to -0.34]; diastolic BP: -0.60 [95% CI -0.95 to -0.25]). Increased physical activity and fitness are associated with favorable retinal vessel diameters.

LIMITATIONS

Long-term studies are needed to substantiate the prognostic relevance of retinal vessel diameters for cardiovascular risk in children.

CONCLUSIONS

Our results indicate that childhood obesity, BP, and physical inactivity are associated with retinal microvascular abnormalities. Retinal vessel diameters seem to be sensitive microvascular biomarkers for cardiovascular risk stratification in children.

Associations of leptin, insulin and lipids with retinal microvasculature in children and adolescents

BACKGROUND

We investigated whether cardiometabolic risk factors measured in serum (total cholesterol [TC], high-density lipoprotein [HDL], triglyceride, leptin, insulin, glucose and insulin resistance) are associated with the retinal microvasculature, a marker of cardiovascular aging, in healthy children and adolescents. Moreover, we tested whether these associations are due to direct biological effects or more indirectly due to adiposity-related side effects.

METHODS

We recruited 168 healthy Flemish children (7-16 years old, 54.8% boys). Blood samples and retinal photographs were taken during clinical examinations. Arteriolar and venular vessel calibers were calculated using a semi-automated computer program. Multivariable regression models were used and adjusted for age, sex, mean arterial pressure (MAP) and alternate retinal caliber. In a second step, we adjusted for body mass index z-score (zBMI).

RESULTS

Only continuous serum leptin was associated with retinal parameters, i.e. wider arterioles; however, this disappeared after adjustment for zBMI. Children with high cardiometabolic risk factors (>90th percentile for serum leptin, insulin and insulin resistance) had wider arterioles compared to children with lower concentrations, even after additional adjustment for zBMI. No significant associations were found with lipids.

CONCLUSIONS

In this healthy population of children and adolescents, the hormones insulin and leptin and insulin resistance were associated with retinal microvasculature alterations, mainly in children with high cardiometabolic factors (>90th percentile), while lipids were not. These associations were independent of zBMI.