Physical activity, television viewing time, and retinal vascular caliber

Effects of Physical Activity and Inactivity on Microvasculature in Children: The Hong Kong Children Eye Study

Purpose

The purpose of this study was to investigate the effects of physical activity and inactivity on the microvasculature in children, as measured from retinal photographs.

Methods

All participants were from the Hong Kong Children Eye Study, a population-based cross-sectional study of children aged 6 to 8 years. They received comprehensive ophthalmic examinations and retinal photography. Their demographics and involvement in physical activity and inactivity were obtained from validated questionnaires. A validated Deep Learning System was used to measure, from retinal photographs, central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE).

Results

In the final analysis of 11,959 participants, 6244 (52.2%) were boys and the mean age was 7.55 (1.05) years. Increased ratio of physical activity to inactivity was associated with wider CRAE (β = 1.033, P = 0.007) and narrower CRVE (β = -2.079, P < 0.001). In the subgroup analysis of boys, increased ratio of physical activity to inactivity was associated with wider CRAE (β = 1.364, P = 0.013) and narrower CRVE (β = -2.563, P = 0.001). The subgroup analysis of girls also showed increased ratio of physical activity to inactivity was associated with narrower CRVE (β = -1.759, P = 0.020), but not CRAE.

Conclusions

Increased activity in children is associated with healthier microvasculature, as shown in the retina. Our study contributes to the growing evidence that physical activity positively influences vascular health from a young age. Therefore, this study also underscores the potential of using the retinal vasculature as a biomarker of cardiovascular health.

Associations between data-driven lifestyle profiles and cognitive function in the AusDiab study

Background

Mounting evidence highlights the importance of combined modifiable lifestyle factors in reducing risk of cognitive decline and dementia. Several a priori additive scoring approaches have been established; however, limited research has employed advanced data-driven approaches to explore this association. This study aimed to examine the association between data-driven lifestyle profiles and cognitive function in community-dwelling Australian adults.

Methods

A cross-sectional study of 4561 Australian adults (55.3% female, mean age 60.9 ± 11.3 years) was conducted. Questionnaires were used to collect self-reported data on diet, physical activity, sedentary time, smoking status, and alcohol consumption. Cognitive testing was undertaken to assess memory, processing speed, and vocabulary and verbal knowledge. Latent Profile Analysis (LPA) was conducted to identify subgroups characterised by similar patterns of lifestyle behaviours. The resultant subgroups, or profiles, were then used to further explore associations with cognitive function using linear regression models and an automatic Bolck, Croon & Hagenaars (BCH) approach.

Results

Three profiles were identified: (1) “Inactive, poor diet” (76.3%); (2) “Moderate activity, non-smokers” (18.7%); and (3) “Highly active, unhealthy drinkers” (5.0%). Profile 2 “Moderate activity, non-smokers” exhibited better processing speed than Profile 1 “Inactive, poor diet”. There was also some evidence to suggest Profile 3 “Highly active, unhealthy drinkers” exhibited poorer vocabulary and verbal knowledge compared to Profile 1 and poorer processing speed and memory scores compared to Profile 2.

Conclusion

In this population of community-dwelling Australian adults, a sub-group characterised by moderate activity levels and higher rates of non-smoking had better cognitive function compared to two other identified sub-groups. This study demonstrates how LPA can be used to highlight sub-groups of a population that may be at increased risk of dementia and benefit most from lifestyle-based multidomain intervention strategies.

Retinal vessel diameters and function in cardiovascular risk and disease

In the last two decades evidence has gradually accumulated suggesting that the eye may be a unique window for cardiovascular risk stratification based on the assessment of subclinical damage of retinal microvascular structure and function. This can be facilitated by non-invasive analysis of static retinal vessel diameters and dynamic recording of flicker light-induced and endothelial function-related dilation of both retinal arterioles and venules. Recent new findings have made retinal microvascular biomarkers strong candidates for clinical implementation as reliable risk predictors. Beyond a review of the current evidence and state of research, the article aims to discuss the methodological benefits and pitfalls and to identify research gaps and future directions. Above all, the potential use for screening and treatment monitoring of cardiovascular disease risk are highlighted. The article provides fundamental comprehension of retinal vessel imaging by explaining anatomical and physiological essentials of the retinal microcirculation leading to a detailed description of the methodological approach. This allows for better understanding of the underlying retinal microvascular pathology associated with the prevalence and development of cardiovascular disease. A body of new evidence is presented on the clinical validity and predictive value of retinal vessel diameters and function for incidence cardiovascular disease and outcome. Findings in children indicate the potential for utility in childhood cardiovascular disease prevention, and the efficacy of exercise interventions highlight the treatment sensitivity of retinal microvascular biomarkers. Finally, coming from the availability of normative data, solutions for diagnostic challenges are discussed and conceptual steps towards clinical implementation are put into perspective.

Lipidomic Signatures of Changes in Adiposity: A Large Prospective Study of 5849 Adults from the Australian Diabetes, Obesity and Lifestyle Study

Lipid metabolism is tightly linked to adiposity. Comprehensive lipidomic profiling offers new insights into the dysregulation of lipid metabolism in relation to weight gain. Here, we investigated the relationship of the human plasma lipidome and changes in waist circumference (WC) and body mass index (BMI). Adults (2653 men and 3196 women), 25–95 years old who attended the baseline survey of the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) and the 5-year follow-up were enrolled. A targeted lipidomic approach was used to quantify 706 distinct molecular lipid species in the plasma samples. Multiple linear regression models were used to examine the relationship between the baseline lipidomic profile and changes in WC and BMI. Metabolic scores for change in WC were generated using a ridge regression model. Alkyl-diacylglycerol such as TG(O-50:2) [NL-18:1] displayed the strongest association with change in WC (β-coefficient = 0.125 cm increment per SD increment in baseline lipid level, p = 2.78 × 10⁻¹¹. Many lipid species containing linoleate (18:2) fatty acids were negatively associated with both WC and BMI gain. Compared to traditional models, multivariate models containing lipid species identify individuals at a greater risk of gaining WC: top quintile relative to bottom quintile (odds ratio, 95% CI = 5.4, 3.8–6.6 for women and 2.3, 1.7–3.0 for men). Our findings define metabolic profiles that characterize individuals at risk of weight gain or WC increase and provide important insight into the biological role of lipids in obesity.

Physical activity and exercise improve retinal microvascular health as a biomarker of cardiovascular risk: A systematic review

BACKGROUND AND AIMS

Physical activity (PA) and fitness are important modulators of vascular ageing and may therefore help expand individual health span. We aimed to systematically review the association of PA and fitness, as well as the effects of exercise interventions on the new microvascular biomarkers retinal arteriolar (CRAE) and venular (CRVE) diameters and the retinal flicker light-induced dilatation (FID) in children and adults.

METHODS

PubMed, Ovid, The Cochrane, EMBASE and Web of Science were searched. 805 studies were found, and 25 full-text articles analysed. Twenty-one articles were included in this systematic review.

RESULTS

Higher PA levels were associated with narrower CRVE in children and adults. Physical inactivity was associated with wider CRVE in both age groups. Combined aerobic and motor skill training in school settings lead to wider CRAE in children. Aerobic exercise interventions in adults with or without CV risk factors induced wider CRAE and narrower CRVE. Studies on the effect of exercise on FID are scarce. In a twelve-week randomized controlled trial, high-intensity interval training significantly improved FID in older patients with CV risk factors.

CONCLUSIONS

Higher PA and fitness levels were associated with improved retinal microvascular health in children and adults. Short-term exercise interventions in healthy children and adults, as well as CV risk patients, improved retinal microvascular structure and function. Exercise has the potential to counteract microvascular remodelling and development of small vessel disease during lifespan. Retinal vessel analysis can differentiate the beneficial effects of exercise on target microvascular organ damage.

Berendschot T, S.A.G. Schouten J, Kroon AA, van der Kallen CJ, Henry RM, van Dongen MC, J.P.M. Eussen S, H.C.M. Savelberg H, van der Berg JD, Schaper NC, Schram MT, Stehouwer CD. Higher levels of daily physical activity are associated with better skin microvascular function in type 2 diabetes-The Maastricht Study

OBJECTIVE

Physical activity may provide a means for the prevention of cardiovascular disease via improving microvascular function. Therefore, this study investigated whether physical activity is associated with skin and retinal microvascular function.

METHODS

In The Maastricht Study, a population-based cohort study enriched with type 2 diabetes (n = 1298, 47.3% women, aged 60.2 ± 8.1 years, 29.5% type 2 diabetes), we studied whether accelerometer-assessed physical activity and sedentary time associate with skin and retinal microvascular function. Associations were studied by linear regression and adjusted for major cardiovascular risk factors. In addition, we investigated whether associations were stronger in type 2 diabetes.

RESULTS

In individuals with type 2 diabetes, total physical activity and higher-intensity physical activity were independently associated with greater heat-induced skin hyperemia (regression coefficients per hour), respectively, 10 (95% CI: 1; 18) and 36 perfusion units (14; 58). In individuals without type 2 diabetes, total physical activity and higher-intensity physical activity were not associated with heat-induced skin hyperemia. No associations with retinal arteriolar %-dilation were identified.

CONCLUSION

Higher levels of total and higher-intensity physical activity were associated with greater skin microvascular vasodilation in individuals with, but not in those without, type 2 diabetes.

Effects of Alternating Standing and Sitting Compared to Prolonged Sitting on Cerebrovascular Hemodynamics

PURPOSE

Previous research suggests that prolonged sitting may acutely reduce cerebral blood flow velocity (CBFv). The purpose of this study was to evaluate the effects of alternating standing and sitting vs prolonged sitting on CBFv.

METHODS

This randomized crossover study enrolled working adults (N=25) with pre-to-stage 1 hypertension not using antihypertensive medications, and a body mass index from 25 to < 40 kg/m2. Subjects participated in two simulated workday conditions: 1) sitting continuously (SIT), and 2) alternating standing and sitting every 30 min (SS). Beat-to-beat systolic, mean and diastolic CBFv were recorded bilaterally for 1 min via insonation of the middle cerebral artery using transcranial Doppler ultrasonography before (morning), between (midday) and following (afternoon) two 3-hr 40 min work periods.

RESULTS

Mean±SD age was 42±12 years, blood pressure (BP) was 132±9/83±8 mmHg, and BMI was 32±5 kg/m2. Cerebrovascular hemodynamics did not differ across condition (P>0.05). There were, however, significant nonlinear effects of time (decrease from morning to midday; increase from midday to afternoon) on systolic CBFv (P=0.014), mean CBFv (P=0.001), diastolic CBFv (P=0.002), and pulsatility index (P=0.038). When overall time effects were evaluated during each time interval, mean and diastolic CBFv significantly decreased morning to midday and all CBFv increased from midday to afternoon. When separated by condition, significant time effects were observed for all CBFv during SIT (P<0.02) but not SS (P>0.05).

CONCLUSIONS

In individuals with elevated BP and BMI, CBFv significantly decreased by midday and increased by afternoon, especially during a workday of prolonged sitting. Future studies should evaluate the combination of frequent walks and a sit-stand desk to break up prolonged sitting.

Acute and chronic effects of soccer game on the retinal vessel diameters in middle-aged adults

BACKGROUND

Although changes in retinal vessel diameter is a new biomarker for the evaluation of cardiovascular risk factors, limited information is available regarding the effects of endurance exercises on retinal microcirculation. Thus, we aimed to evaluate both chronic and acute effects of soccer game on the diameters of retinal vessels in middle-aged players.

METHODS

Retinal vessel diameters were measured in 12 middle-aged amateur players (44.4±7.0 years of age) with more than four years of soccer playing experience and 12 age-matched sedentary adults (49.7±7.1 years of age). In soccer players, diameters were also measured immediately after the soccer game. Cardiovascular risk profiles (anthropometry and body composition and blood pressure [BP]) and physical activity levels were also measured.

RESULTS

Soccer players had wider retinal vessels than controls (P<0.05), resulting in greater arteriolar-to-venular diameter ratio (AVR) (P<0.05). Greater sports-related physical activity, lower body mass index (BMI) and fat mass were observed for soccer players compared to the controls (P<0.05), whereas BP did not differ. Physical activity level correlated positively with temporal retinal arteriolar (TRA) diameter and with AVR (P<0.05), whereas TRA diameter correlated negatively with BMI and fat mass (P<0.05). A significant correlation between temporal retinal venule (TRV) diameter and TRA diameter (P<0.05) was observed. The acute soccer game increased BP (P<0.05) and induced TRV dilatation (P<0.05).

CONCLUSIONS

In middle-aged amateur soccer players, improvement of the retinal microcirculation was observed. Cardiovascular risk factors and physical inactivity were associated with adverse retinal microvascular alterations. In terms of acute effects, soccer play causes venular, but not arteriolar dilatation for middle-aged adults.

Retinal vascular diameters in relation to physical activity in Danish children - The CHAMPS Eye Study

Our objective was to determine associations between retinal vascular caliber and physical activity (PA) in a school-based child cohort. In a prospective study, we created a childhood cumulative average PA-index using objectively measured PA (accelerometry) assessed at four periods between 2009 and 2015. Cumulative exposure to PA intensities was estimated. Cross-sectional examinations on biomarkers, anthropometry, and ophthalmological data including retinal fundus photographs were performed in 2015. Semi-automated measurements of retinal vascular diameters were performed and summarized into central retinal arteriolar and venular equivalents (CRAE, CRVE). We included 307 participants. Mean age in 2015 was 15.4 years (0.7). The mean CRAE and CRVE were 156.5 μm (2.8) and 217.6 μm (7.7), respectively. After adjusting for age, gender, and axial length, more time in PA was independently related to thinner retinal venules (β-coefficient = -1.25 μm/%, 95% confidence interval = -2.20, -0.30, P < .01). Sedentary time was associated with wider venules (P < .01). Furthermore, birthweight (β-coefficient = 0.56 μm/%, 95% confidence interval = 0.18, 0.95, P < .01) was associated with CRVE. Blood pressure was associated with thinner retinal arterioles (β-coefficient = -0.19 μm/mmHg, 95% confidence interval = -0.36, -0.01, P = .04). We concluded that children with higher PA in childhood had thinner retinal venular caliber. Our results suggest that PA during childhood positively impacts the retinal microcirculation and that retinal vascular analysis may be a possible assessment to detect microvascular impairments in children with an increased risk of future cardiovascular disease.

Physical activity, visual impairment, and eye disease

Numerous studies have demonstrated physical activity is a strong factor in overall health and well-being, and a growing body of literature, reviewed herein, suggests that several eye conditions, including glaucoma, age-related macular degeneration, and diabetic retinopathy, are associated with lower activity levels. Likewise, physical activity levels are lower in persons with worse vision. Research in this area has utilized both self-reported physical activity measures as well as objective measures of activity (i.e., accelerometers), each of which have their own strengths and limitations. Putative mechanisms explaining the association of various eye conditions with physical activity are discussed. It is possible that activity restriction occurs as a downstream consequence of eye disease/visual impairment, that activity restriction causes eye disease/visual impairment, or that causality is bidirectional; evidence supporting each of these theories is put forth. An improved understanding of the relationship between physical activity and eye disease will highlight potential secondary health risks resulting from eye disease, and can help determine whether activity might serve as a readily available preventative measure to prevent specific eye conditions.

Assessing Microvascular Function in Humans from a Chronic Disease Perspective

Microvascular dysfunction (MVD) is considered a crucial pathway in the development and progression of cardiometabolic and renal disease and is associated with increased cardiovascular mortality. MVD often coexists with or even precedes macrovascular disease, possibly due to shared mechanisms of vascular damage, such as inflammatory processes and oxidative stress. One of the first events in MVD is endothelial dysfunction. With the use of different physiologic or pharmacologic stimuli, endothelium-dependent (micro)vascular reactivity can be studied. This reactivity depends on the balance between various mediators, including nitric oxide, endothelin, and prostanoids, among others. The measurement of microvascular (endothelial) function is important to understand the pathophysiologic mechanisms that contribute to MVD and the role of MVD in the development and progression of cardiometabolic/renal disease. Here, we review a selection of direct, noninvasive techniques for measuring human microcirculation, with a focus on methods, interpretation, and limitations from the perspective of chronic cardiometabolic and renal disease.

Physical activity and its correlation to diabetic retinopathy

PURPOSE

The lack of physical activity, along with obesity, smoking, hypertension and hyperglycaemia are considered as risk factors for the occurrence of diseases such as diabetes. Primary objective of the study was to investigate potential correlation between physical activity and diabetic retinopathy.

PATIENTS AND METHODS

Three hundred and twenty patients were included in the study: 240 patients with diabetes type 2 (80 patients with mild to moderate non-proliferative diabetic retinopathy, 80 patients with severe to very severe non-proliferative diabetic retinopathy and 80 ones with proliferative diabetic retinopathy) were compared with 80 non-diabetic patients (control group). Physical activity of patients was assessed by the international physical activity questionnaire (IPAQ, 2002). HbA1c and BMI were also measured in diabetic patients. Group comparisons were attempted for levels of physical activity and sedentary behavior.

RESULTS

Total physical activity was decreased in patients with severe to very severe non-proliferative diabetic retinopathy and proliferative diabetic retinopathy as compared to patients with mild to moderate non-proliferative diabetic retinopathy and to the control group (p<0.05). Significant negative correlation was detected between HbA1c levels, BMI and physical activity (both p<0.05). Moreover, significant negative correlation between the severity of diabetic retinopathy and physical activity has been demonstrated (p<0.05).

CONCLUSIONS

Increased physical activity is associated with less severe levels of diabetic retinopathy, independent of the effects of HbA1c and BMI.

Associations between television viewing and physical activity and low back pain in community-based adults: A cohort study

Two systematic reviews concluded that there was limited evidence to support an association between physical activity and sedentary behavior and developing low back pain (LBP). The aim of this study was to examine the associations of physical activity and television viewing time with LBP intensity and disability in community-based adults.Five thousand fifty-eight participants (44% men) of the Australian Diabetes, Obesity and Lifestyle Study had physical activity and television viewing time measured in 1999 to 2000, 2004 to 2005, and 2011 to 2012, and LBP intensity and disability assessed in 2013 to 2014 using the Chronic Pain Grade Questionnaire. Multinomial logistic regressions were used to estimate the odds ratio for LBP intensity and disability associated with physical activity and television viewing time. Analyses were adjusted for age, education, smoking, dietary guideline index score, body mass index, and mental component summary score. To test whether associations of physical activity or television viewing time with LBP intensity and disability were modified by sex, obesity, or age, interactions were tested using the likelihood ratio test.As gender modified the associations between physical activity and television viewing time and LBP disability (P = 0.05), men and women were examined separately. A total of 81.7% men and 82.1% women had LBP. Most men (63.6%) and women (60.2%) had low intensity LBP with fewer having high intensity LBP (18.1% men, 21.5% women). Most participants had no LBP disability (74.5% men, 71.8% women) with the remainder reporting low (15.8% men, 15.3% women) or high (9.7% men, 12.9% women) LBP disability. Insufficient physical activity (<2.5 hours/week) was not associated with LBP intensity or disability. High television viewing time (≥2 hours/day) was associated with greater prevalence of LBP disability in women (low disability OR 1.35, 95% CI 1.04-1.73; high disability OR 1.29, 95% CI 1.01-1.72).Although it needs to be confirmed in RCTs our findings suggest that targeting time spent watching television and possibly other prolonged sedentary behaviors may have the potential to reduce LBP disability in community-based adults, particularly in women.

Physical Activity, Sedentary Behaviors, and Retinal Vascular Caliber in Children and Adolescents With Type 1 Diabetes

PURPOSE

The aim of this study was to investigate associations of physical activity and sedentary behaviors with retinal vascular caliber in children and adolescents with type 1 diabetes.

DESIGN

This was a hospital-based cross-sectional study.

METHODS

A study of 122 children and adolescents with type 1 diabetes was conducted over an 8-month period. Self-reported physical activity time and time spent watching TV or playing computer or video games were obtained using interviewer-administered questionnaires. Retinal vascular caliber was measured by a trained grader using a standardized protocol and later summarized as central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE) using a semiautomated computer program.

RESULTS

After adjusting for confounders (age, sex, ethnicity, body mass index, systolic blood pressure, HbA1c, maternal smoking status, age at which cow's milk was introduced, and CRVE/CRAE, respectively), narrower CRAE was independently related to more time spent playing computer/video games [ExpB = -3.85; 95% confidence interval (CI), -6.41 to -1.29; P = 0.004], whereas wider CRVE was independently related to lower physical activity level (ExpB = -1.08; 95% CI, -2.01 to -0.15; P = 0.03) and more time spent playing computer/video games (ExpB = 4.72; 95% CI, 0.52-8.92; P = 0.02). Television viewing time was not associated with retinal vascular caliber after adjustment.

CONCLUSIONS

The results of this study suggest that physical activity and sedentary behaviors in the form of "screen viewing time" are associated with retinal vessel caliber early in life. These results suggest that retinal vascular caliber may provide prognostic information beyond current traditional cardiovascular risk factors. Future longitudinal and interventional studies are warranted to evaluate the relevance of these observations.

Sedentary behavior: understanding and influencing adults' prolonged sitting time

Too much sitting is now understood to be a health risk that is additional to, and distinct from, too little exercise. There is a rapidly-accumulating evidence on relationships of prolonged sedentary time and patterns of sedentary time with cardio-metabolic risk biomarkers and health outcomes. There is, however, the need to gather dose-response evidence and develop a broader understanding of the set of mechanisms linking sedentary behavior to health outcomes. In addition to the further understanding of the associated health risks, there is a new health-behavior, and epidemiological and experimental research agenda to be pursued, which include measurement studies; understanding the relevant determinants-particularly environmental determinants of sedentary behavior; and, developing effective interventions. A broad-based body of evidence is needed to inform the research-translation agenda-identifying and developing the future public health initiatives, environmental and policy changes and clinical guidelines that may be required.

Influence of Physical Activity and Screen Time on the Retinal Microvasculature in Young Children

Objective—

It is not clear whether physical activity and sedentary behavior affect retinal microvascular caliber. We investigated associations among physical activity (outdoor and indoor sporting activities), sedentary behaviors (including screen time, television [TV] viewing, and computer and videogame usage), and retinal microvascular caliber in schoolchildren.

Methods and Results—

Six-year-old students (1765/2238) from a random cluster sample of 34 Sydney schools were examined. Parents completed questionnaires about physical and sedentary activities. Retinal images were taken, and retinal vessel caliber was quantified. After adjusting for age, sex, ethnicity, eye color, axial length, body mass index, birth weight, and mean arterial blood pressure, children who spent more time in outdoor sporting activities (in the highest tertile of activity) had 2.2 μm (95% CI 0.65 to 3.71) wider mean retinal arteriolar caliber than those in the lowest tertile ( P trend =0.004). Increasing quartiles of time spent watching TV were associated with narrower mean retinal arteriolar caliber ≈2.3 μm (95% CI 0.73 to 3.92), P trend =0.003.

Conclusion—

These data suggest that physical activity could have a beneficial influence, whereas screen time has a potential adverse influence on retinal microvascular structure. The magnitude of arteriolar narrowing associated with each hour daily of TV viewing is similar to that associated with a 10-mm Hg increase in systolic blood pressure in children.

Physical activity, television viewing time, and retinal microvascular caliber: the multi-ethnic study of atherosclerosis

Physical activities and sedentary behaviors are 2 broad classes of behavior that may be clearly distinguished from each other and have different patterns of determinants. The authors examined the associations of physical activity and television viewing time with retinal vascular caliber among US adults (n = 5,893) from 4 racial/ethnic groups in the Multi-Ethnic Study of Atherosclerosis (2002-2004) that included non-Hispanic whites, blacks, Hispanics, and Chinese. Physical activity and television viewing time were assessed by using a questionnaire, and vascular calibers (arteriolar and venular) were measured from digital retinal photographs. Those in the lowest quartile of physical activity had wider retinal venular caliber compared with those in the highest quartile in multivariate models adjusted for demographic, cardiovascular, behavioral, and inflammatory risk factors. This was noted in non-Hispanic whites and Hispanics but not in blacks or Chinese. For television viewing time, non-Hispanic whites (but not the other racial/ethnic groups) who were in the highest quartile of television viewing time had wider retinal venular caliber compared with those in the lowest quartile. No associations were noted with arteriolar caliber. Lower levels of physical activity (among non-Hispanic whites and Hispanics) and higher levels of television viewing time (among whites) are associated with wider retinal venules.