Variation of Laminar Depth in Normal Eyes With Age and Race

PURPOSE. To determine if laminar depth (LD) and prelaminar tissue volume (PTV) are associated with age and race in healthy human eyes. METHODS. Optic nerve head images from enhanced depth imaging spectral-domain optical coherence tomography of 166 normal eyes from 84 subjects of African descent (AD) and European descent (ED) were manually delineated to identify the principal surfaces: internal limiting membrane, Bruch's membrane (BM), anterior sclera (AS), and anterior surface of the lamina cribrosa. These four surfaces defined the LD and PTV using Bruch's membrane opening (BMO) and AS for reference structures. Generalized estimating equations were used to evaluate whether the effect of age on each outcome was differential by race. RESULTS. When age was analyzed as a continuous variable, the interaction term between age and race was statistically significant for mean LD BMO (P ¼ 0.015) and mean LD AS (P ¼ 0.0062) after adjusting for axial length and BMO area. For every 1-year increase in age, the LD AS was greater on average by 1.78 lm in AD subjects and less by 1.71 lm in ED subjects. Mean PTV was lower in the older subjects (1248 3 10 6 lm 3 AD, 881 3 10 6 lm 3 ED) compared to the younger subjects (1316 3 10 6 lm 3 AD, 1102 3 10 6 lm 3 ED) in both groups. CONCLUSIONS. With increasing age, the LD changes differently across racial groups in normal subjects. The LD in ED subjects showed a significantly decreasing slope suggesting that the lamina moves anteriorly with age in this group. Keywords: lamina cribrosa, laminar depth, spectral-domain optical coherence tomography I ndividuals of African descent (AD) have a higher prevalence of primary open-angle glaucoma with worse visual outcomes from the disease compared to those of European descent (ED). 1-5 Investigation into the many possible causes of this disparity reveals racial and ethnic differences in the anatomy of the optic nerve head (ONH). 3,6-14 Variation in ONH parameters, such as larger optic discs, deeper cups, and thicker overall retinal nerve fiber layer thicknesses in AD individuals

Cardiovascular inflammation in healthy women: multilevel associations with state-level prosperity, productivity and income inequality

<p>Abstract</p> <p>Background</p> <p>Cardiovascular inflammation is a key contributor to the development of atherosclerosis and the prediction of cardiovascular events among healthy women. An emerging literature suggests biomarkers of inflammation vary by geography of residence at the state-level, and are associated with individual-level socioeconomic status. Associations between cardiovascular inflammation and state-level socioeconomic conditions have not been evaluated. The study objective is to estimate whether there are independent associations between state-level socioeconomic conditions and individual-level biomarkers of inflammation, in excess of individual-level income and clinical covariates among healthy women.</p> <p>Methods</p> <p>The authors examined cross-sectional multilevel associations among state-level socioeconomic conditions, individual-level income, and biomarkers of inflammation among women (n = 26,029) in the Women's Health Study, a nation-wide cohort of healthy women free of cardiovascular diseases at enrollment. High sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion molecule-1 (sICAM-1) and fibrinogen were measured between 1993 and 1996. Biomarker levels were examined among women within quartiles of state-level socioeconomic conditions and within categories of individual-level income.</p> <p>Results</p> <p>The authors found that favorable state-level socioeconomic conditions were correlated with lower hsCRP, in excess of individual-level income (e.g. state-level real per capital gross domestic product fixed effect standardized Βeta coefficient [Std B] -0.03, 95% CI -0.05, -0.004). Individual-level income was more closely associated with sICAM-1 (Std B -0.04, 95% CI -0.06, -0.03) and fibrinogen (Std B -0.05, 95% CI -0.06, -0.03) than state-level conditions.</p> <p>Conclusions</p> <p>We found associations between state-level socioeconomic conditions and hsCRP among healthy women. Personal household income was more closely associated with sICAM-1 and fibrinogen than state-level socioeconomic conditions. Additional research should examine these associations in other cohorts, and investigate what more-advantaged states do differently than less-advantaged states that may influence levels of cardiovascular inflammation among healthy women.</p

Visual, Attentional, and Cognitive Risk Factors for Motor Vehicle Collision Involvement among Older Adults

Motor vehicle collisions are a major public health problem for older adults in the United States. In 2013, there were 5,671 older adults killed and an estimated 222,000 injured in motor vehicle crashes. After adjusting for miles driven, the risk of crashing increases rapidly after age 70, nearly equal to that of younger drivers whose crash rate is the highest among all age groups. Driving is a highly complex task that relies on a variety of visual and cognitive functions. A large body of work has demonstrated that drivers with visual sensory impairments and/or higher-order visual-cognitive processing deficits, those who engage in secondary tasks, and those with cognitive impairment are at increased risk for collision involvement. To date, the majority of population-based research studies have utilized accident reports from police agencies. While accident reports provide a wealth of information on the circumstances of the crash, they are limited on the availability and scope of on-road data from actual driving situations. Therefore, the goal of this dissertation was to make use of an innovative approach to study risk factors for driving safety using naturalistic driving data from the Strategic Highway Research Program 2. In addition, the Mini-Mental Status Exam is widely regarded as a valid and reliable screener for general cognitive impairment, is very brief, and has been used successfully with diverse populations. However, results from prior studies are inconsistent with respect to whether MMSE scores are associated with crash involvement. Using naturalistic driving data, we observed higher rates of crash involvement among those with contrast sensitivity impairment compared to those without impairment. We also found that secondary task involvement was not associated with a higher risk of crash involvement among older drivers. Finally, in a population-based sample of licensed drivers, we found that general cognitive impairment status was not associated with future crash involvement; however, a 1-year decline in cognitive function was a significant risk factor for at-fault crash involvement. In conclusion, this dissertation highlights the importance of visual and cognitive functioning as well as behavioral characteristics of older drivers as risk factors for crash involvement

The driving visual field and a history of motor vehicle collision involvement in older drivers: A population-based examination

Purpose We designed a visual field test focused on the field utilized while driving to examine associations between field impairment and motor vehicle collision involvement in 2,000 drivers ≥70 years old. Methods The "driving visual field test" involved measuring light sensitivity for 20 targets in each eye, extending 15° superiorly, 30° inferiorly, 60° temporally and 30° nasally. The target locations were selected on the basis that they fell within the field region utilized when viewing through the windshield of a vehicle or viewing the dashboard while driving. Monocular fields were combined into a binocular field based on the more sensitive point from each eye. Severe impairment in the overall field or a region was defined as average sensitivity in the lowest quartile of sensitivity. At-fault collision involvement for five years prior to enrollment was obtained from state records. Poisson regression was used to calculate crude and adjusted rate ratios examining the association between field impairment and at-fault collision involvement. Results Drivers with severe binocular field impairment in the overall driving visual field had a 40% increased rate of at-fault collision involvement (RR 1.40, 95%CI 1.07-1.83). Impairment in the lower and left fields was associated with elevated collision rates (RR 1.40 95%CI 1.07-1.82 and RR 1.49, 95%CI 1.15-1.92, respectively), whereas impairment in the upper and right field regions was not. Conclusions Results suggest that older drivers with severe impairment in the lower or left region of the driving visual field are more likely to have a history of at-fault collision involvement

Prevalence of and factors associated with distraction among public transit bus drivers

Objective: Recent research has suggested that driver distraction is a major cause of driving performance impairment and motor vehicle collisions. Research on the topic has focused on passenger vehicles, with studies suggesting that drivers may be distracted nearly 33% of the time spent driving. To date, no study has examined the prevalence of distraction specifically among public transit bus drivers. Methods: Over a three-month period, trained investigators observed and recorded distraction behaviors of bus drivers. Distraction prevalence was compared by route characteristics (e.g., geographic area, travel speed) using chi-square test. A general estimating equation logistic regression was used to estimate p-values for distraction prevalence by driver demographics. Results: Overall, there was a 39% prevalence of distraction. The most prevalent distractions were due to interactions with another passenger. Distractions were more prevalent among drivers≥50 years of age, on city streets or highways (relative to residential streets), and when there were more than 20 passengers. Distractions were the least prevalent in suburban areas, with the highest prevalence observed in city centers and rural areas. Conclusions: Driver distraction is a common problem for public transit bus drivers, mainly due to other passengers. Drivers should be educated on the hazards of distracted driving and on ways to avoid distraction

Relationship between Areas of Cognitive Functioning on the Mini-Mental State Examination and Crash Risk

Previous studies have suggested that the pattern of cognitive impairment in crash-involved older drivers is different from non-crash-involved older drivers. This study assessed the relationship between seven areas of cognitive functioning (orientation to time, orientation to place, registration, attention and calculation, recall, language, and visual construction) on the Mini-Mental State Examination (MMSE) collected at baseline and rates of future crash involvement in a prospective population-based sample of older drivers. Motor vehicle collision (MVC) involvement was obtained from the Alabama Department of Public Safety. Poisson regression was used to calculate crude and adjusted rate ratios (RR). Older drivers having difficulties in place orientation were more than 6 times (95% CI 1.90–19.86) more likely to be involved in a future crash (adjusted RR = 6.14, 95% confidence interval (CI) 1.90–19.86) and at-fault crash (adjusted RR = 6.39, 95% CI 1.51–27.10). Impairment in the other cognitive areas was not associated with higher rates of crash or at-fault crash involvement. The findings were validated in an independent sample of high-risk older drivers and a similar pattern of results was observed. Spatial orientation impairment can help identify older drivers who are more likely to crash in the future

Motor Vehicle Collision Involvement among Persons with Hemianopia and Quadrantanopia

Persons with homonymous quadrantanopia and hemianopia experience driving restrictions, yet there is little scientific evidence to support driving prohibition among persons with these conditions. This retrospective cohort study compares motor vehicle collision (MVC) rates among 27 current licensed drivers with hemianopic and quadrantanopic field defects, who were ≥6 months from the brain injury date with that of 27 age-matched drivers with normal visual fields. Information regarding all police-reported MVCs that occurred over a period of nine years was obtained. MVC rates per year and per mile travelled were calculated and compared using conditional Poisson regression. Drivers with hemianopia or quadrantanopia had more MVCs per mile driven compared to drivers with normal visual fields; specifically their overall MVC rate was 2.45-times (95% confidence interval (CI) 0.89–3.95) higher and their at-fault MVC rate was 2.64-times (95% CI 1.03–6.80) higher. This study indicates that drivers with hemianopia or quadrantanopia have elevated MVC rates. This is consistent with previous research despite studies showing wide individual variability from excellent to poor driving skills. Future research should focus on the functional and driving performance characteristics associated with superior driving skills and/or those that may be amenable to improvement via behavioral and/or engineering interventions

Higher Serum Insulin Concentrations Positively Influence the Bone Mineral Density in African American Adolescents

Background: Puberty is a developmental stage of increased insulin resistance that also is a critical period for bone mass accrual. Historically, African Americans (AA) have lesser risk for osteoporotic fractures compared to European Americans (EA). AA also have higher incidence of insulin resistance. The possibility that bone health and insulin secretion or concentrations are linked has not been investigated. Aims: We aimed to examine the associations of bone mineral density (BMD) and bone mineral apparent density (BMAD) with insulin sensitivity and secretion in healthy adolescent girls and healthy female adults and to evaluate ethnic differences in these associations. Study Design: Observational cohort design. Place and Duration of the Study: University of Alabama at Birmingham, between January 2010 and September 2011. Methodology: Healthy, female, non-smoking adolescents and young adults (14-55 years) were enrolled in this observational cohort study. Results: Adolescents had significantly higher fasting insulin (P=0.0002), insulin area under the curve [AUC] (P= 0.0004) and lower insulin sensitivity (P=0.0005) compared to adults. Among adolescents, AA race was significantly associated with BMD (β=0.086, P=0.01) and BMAD (β=0.0075, P=0.002); however, adjusting for insulin AUC explained this difference. Insulin AUC (β=0.0006, P=0.029) and fasting insulin (β=0.0005, P=0.01) were positively associated with BMAD only in AA adolescents. Insulin AUC and fasting insulin were not significant predictors of BMD for adults. Conclusion: The higher insulin concentration among AA adolescents is associated with increased BMD and higher BMAD

The Prevalence of Distraction Among Passenger Vehicle Drivers: A Roadside Observational Approach

<div><p><b>Objective:</b> Distracted driving contributes to a large proportion of motor vehicle crashes, yet little is known about the prevalence of distracted driving and the specific types of distracting behaviors. The objective of this study was to estimate the prevalence of driver distraction using a roadside observational study design.</p><p><b>Methods:</b> A cross-sectional survey involving direct roadside observation was conducted at 11 selected intersections. Trained investigators observed a sample of passenger vehicles and recorded distraction-related behaviors, driver characteristics, and contextual factors such as vehicle speed and traffic flow.</p><p><b>Results:</b> Of the 3,265 drivers observed, the prevalence of distracted driving was 32.7%. Among those involved in a distracting activity, the most frequently observed distractions included interacting with another passenger (53.2%, where passengers were present), talking on the phone (31.4%), external-vehicle distractions (20.4%), and texting/dialing a phone (16.6%). The prevalence of talking on the phone was higher among females than males (38.6% vs. 24.3%), whereas external vehicle distractions were higher among males than females (25.8% vs. 24.3%). Drivers <30 years were observed being engaged in any distracting activity, interacting with other passengers, and texting/dialing more frequently than drivers aged 30–50 and >50 years. Drivers were engaged in distracting behaviors more frequently when the car was stopped.</p><p><b>Conclusions:</b> When using similar methodology, roadside observational studies generate comparable prevalence estimates of driver distraction as naturalistic driving studies. Driver distraction is a common problem among passenger vehicle drivers. Despite the increased awareness on the dangers of texting and cell phone use while driving, these specific activities were 2 of the most frequently observed distractions. There is a continued need for road safety education about the dangers of distracted driving, especially for younger drivers.</p></div

Association between glaucoma and at–fault motor vehicle collision involvement among older drivers

Objective\ud \ud To examine the association between glaucoma and motor vehicle collision (MVC) involvement among older drivers, including the role of visual field impairment that may underlie any association found.\ud \ud Design\ud \ud A retrospective population-based study\ud \ud Participants\ud \ud A sample of 2,000 licensed drivers aged 70 years and older who reside in north central Alabama.\ud \ud Methods\ud \ud At-fault MVC involvement for five years prior to enrollment was obtained from state records. Three aspects of visual function were measured: habitual binocular distance visual acuity, binocular contrast sensitivity and the binocular driving visual field constructed from combining the monocular visual fields of each eye. Poisson regression was used to calculate crude and adjusted rate ratios (RR) and 95% confidence intervals (CI).\ud \ud Main Outcomes Measures\ud \ud At-fault MVC involvement for five years prior to enrollment. \ud \ud Results\ud \ud Drivers with glaucoma (n = 206) had a 1.65 (95% confidence interval [CI] 1.20-2.28, p = 0.002) times higher MVC rate compared to those without glaucoma after adjusting for age, gender and mental status. Among those with glaucoma, drivers with severe visual field loss had higher MVC rates (RR = 2.11, 95% CI 1.09-4.09, p = 0.027), whereas no significant association was found among those with impaired visual acuity and contrast sensitivity. When the visual field was sub-divided into six regions (upper, lower, left, and right visual fields; horizontal and vertical meridians), we found that impairment in the left, upper or lower visual field was associated with higher MVC rates, and an impaired left visual field showed the highest RR (RR = 3.16, p = 0.001) compared to other regions. However, no significant association was found in deficits in the right side or along the horizontal or vertical meridian.\ud \ud Conclusions\ud \ud A population-based study suggests that older drivers with glaucoma are more likely to have a history of at-fault MVC involvement than those without glaucoma. Impairment in the driving visual field in drivers with glaucoma appears to have an independent association with at-fault MVC involvement, whereas visual acuity and contrast sensitivity impairments do not