Survival Bias When Assessing Risk Factors for Age-Related Macular Degeneration: A Tutorial with Application to the Exposure of Smoking

CheekAge: a next-generation buccal epigenetic aging clock associated with lifestyle and health

Epigenetic aging clocks are computational models that predict age using DNA methylation information. Initially, first-generation clocks were developed to make predictions using CpGs that change with age. Over time, next-generation clocks were created using CpGs that relate to both age and health. Since existing next-generation clocks were constructed in blood, we sought to develop a next-generation clock optimized for prediction in cheek swabs, which are non-invasive and easy to collect. To do this, we collected MethylationEPIC data as well as lifestyle and health information from 8045 diverse adults. Using a novel simulated annealing approach that allowed us to incorporate lifestyle and health factors into training as well as a combination of CpG filtering, CpG clustering, and clock ensembling, we constructed CheekAge, an epigenetic aging clock that has a strong correlation with age, displays high test-retest reproducibility across replicates, and significantly associates with a plethora of lifestyle and health factors, such as BMI, smoking status, and alcohol intake. We validated CheekAge in an internal dataset and multiple publicly available datasets, including samples from patients with progeria or meningioma. In addition to exploring the underlying biology of the data and clock, we provide a free online tool that allows users to mine our methylomic data and predict epigenetic age.

Predictive Performance of an Updated Polygenic Risk Score for Age-Related Macular Degeneration

PURPOSE

A recent genome-wide association study of age-related macular degeneration (AMD) identified new AMD-associated risk variants. These variants now can be incorporated into an updated polygenic risk score (PRS). This study aimed to assess the performance of an updated PRS, PRS2023, in an independent cohort of older individuals with retinal imaging data and to compare performance with an older PRS, PRS2016.

DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 4175 participants of European ancestry, 70 years of age or older, with genotype and retinal imaging data.

METHODS

We used logistic regression models and area under the receiver operating characteristic curve (AUC) to assess the performance of PRS2023 compared with PRS2016. AMD status and severity were graded using color fundus photography.

MAIN OUTCOME MEASURES

Association of PRS2023 and PRS2016 with AMD risk at baseline.

RESULTS

At enrollment among 4175 participants, 2605 participants (62.4%) had no AMD and 853 participants (20.4%), 671 participants (16.1%), and 46 participants (1.1%) had early, intermediate, and late-stage AMD, respectively. More than 27% of the participants with a high PRS2023 (top quartile) had intermediate or late-stage AMD, compared with < 15% for those in the middle 2 quartiles and less than 13% for those in the lowest quartile. Both PRS2023 and PRS2016 were associated significantly with AMD after adjustment for age, sex, smoking status, and lipid levels, with increasing odds ratios (ORs) for worsening AMD grades. PRS2023 outperformed PRS2016 (P = 0.03 for all AMD and P = 0.03 for late AMD, DeLong test comparing AUC). PRS2023 was associated with late-stage AMD with an adjusted OR of 5.05 (95% confidence interval [CI], 3.41-7.47) per standard deviation. The AUC of a model containing conventional or nongenetic risk factors and PRS2023 was 91% (95% CI, 87%-95%) for predicting late-stage AMD, which improved 12% over the model without the PRS (AUC, 79%; P < 0.001 for difference).

CONCLUSIONS

A new PRS, PRS2023, for AMD outperforms a previous PRS and predicts increasing risk for late-stage AMD (with stronger association for more severe imaging-confirmed AMD grades). Our findings have clinical implications for the improved prediction and risk stratification of AMD.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Self-rated eyesight among healthy older Australians: Baseline results of the ASPREE Longitudinal Study of Older Persons

BACKGROUND

We aimed to describe the self-reported level of eyesight amongst a cohort of relatively healthy older Australian adults, and to investigate associations between poorer self-rated eyesight and demographic, health, and functional characteristics METHODS: The ASPirin in Reducing Events in the Elderly (ASPREE) Longitudinal Study of Older Persons (ALSOP) study was embedded in a multisite trial which recruited independently living Australians from general practices (2010-2014). Self-rated eyesight was recorded on a paper-based questionnaire as Excellent, Good, Fair, Poor, Very poor, or Completely blind at the baseline study wave RESULTS: Data from 14 592 participants (aged 70-95 years, 54.61% female) were included in this cross-sectional analysis. Eighty percent of participants reported excellent or good eyesight (n = 11 677). People with complete blindness were precluded from enrolling but 299 participants (2.0%) reported poor or very poor eyesight, and 2616 rated their eyesight as fair (17.9%). Lower levels of eyesight were associated with being older, female, fewer years of formal education, a primary language other than English, smoking, and self-reported macular degeneration, glaucoma, retinopathy, cataracts, and hearing problems (each p ≤ 0.021). People with lower levels of eyesight had a higher number of falls, frailty characteristics, and depressive symptoms, and lower mental and physical health functioning scores (each p < 0.001) CONCLUSIONS: Whilst most of these healthy older Australians reported good or excellent eyesight, a notable minority reported poor or very poor eyesight, and this was associated with a range of poorer health measures. These findings support the need for additional resources to prevent vision loss and associated sequelae.

The neighborhood context and all-cause mortality among older adults in Puerto Rico

Background

Recent efforts have been made to collect data on neighborhood-level attributes and link them to longitudinal population-based surveys. These linked data have allowed researchers to assess the influence of neighborhood characteristics on the health of older adults in the US. However, these data exclude Puerto Rico. Because of significantly differing historical and political contexts, and widely ranging structural factors between the island and the mainland, it may not be appropriate to apply current knowledge on neighborhood health effects based on studies conducted in the US to Puerto Rico. Thus, we aim to (1) examine the types of neighborhood environments older Puerto Rican adults reside in and (2) explore the association between neighborhood environments and all-cause mortality.

Methods

We linked data from the 2000 US Census to the longitudinal Puerto Rican Elderly Health Conditions Project (PREHCO) with mortality follow-up through 2021 to examine the effects of the baseline neighborhood environment on all-cause mortality among 3,469 participants. Latent profile analysis, a model-based clustering technique, classified Puerto Rican neighborhoods based on 19 census block group indicators related to the neighborhood constructs of socioeconomic status, household composition, minority status, and housing and transportation. The associations between the latent classes and all-cause mortality were assessed using multilevel mixed-effects parametric survival models with a Weibull distribution.

Results

A five-class model was fit on 2,477 census block groups in Puerto Rico with varying patterns of social (dis)advantage. Our results show that older adults residing in neighborhoods classified as Urban High Deprivation and Urban High-Moderate Deprivation in Puerto Rico were at higher risk of death over the 19-year study period relative to the Urban Low Deprivation cluster, controlling for individual-level covariates.

Conclusions

Considering Puerto Rico's socio-structural reality, we recommend that policymakers, healthcare providers, and leaders across industries to (1) understand how individual health and mortality is embedded within larger social, cultural, structural, and historical contexts, and (2) make concerted efforts to reach out to residents living in disadvantaged community contexts to understand better what they need to successfully age in place in Puerto Rico.

Association Between Multi-Morbidities and Polypharmacy Among Older Adults at an Academic Medical Center in Saudi Arabia

Background

Polypharmacy, or the routine use of five or more medications, can result in impacting patients' quality of life.

Objective

to examine the association between multi-morbidities and polypharmacy, and to examine prescription practices in the elderly.

Methods

This is a retrospective cross-sectional study. Data were gathered from electronic medical records (EMR) at King Fahad University Hospital (KFHU) and the Family & Community Medicine Center (FCMC) of Imam Abdulrahman bin Faisal University (IAU), between January 1, 2019, and December 31, 2020. We included individuals aged 60 and above with at least one dispensed prescription in 2019 and 2020. Of the 76,216 patient records reviewed, 5,060 met the inclusion criteria. Polypharmacy was defined as a monthly average of five or more prescribed medications. The prevalence of polypharmacy was calculated by year, sex, and age group, and findings were summarized using mean medication numbers and standard deviations for each stratum. An app using R programming language was developed to help visualize patients' medication histories through interactive plots.

Results

Polypharmacy prevalence was 46% in 2019 and 44.6% in 2020. The mean and standard deviation of medications per person was 5.17 (3.42) in 2019 and 5.04 (3.37) in 2020. Females had a higher average number of medications than males, 5.17 (3.47) vs 5.04 (3.32). The age group of 80-85 had the highest number of medications at 5.6 (3.6), while those aged 90 and above had the lowest number at 4.48 (2.64). The presence of comorbidities was positively associated with the mean monthly medication count (P value < 0.01).

Conclusion

Our study revealed a high prevalence of polypharmacy among elderly patients at KFHU/FCMC, and a positive association with multi-morbidities. Consequently, measures must be taken to mitigate this globally emerging issue's impact and rapid progression.

The Need for Artificial Intelligence Based Risk Factor Analysis for Age-Related Macular Degeneration: A Review

In epidemiology, a risk factor is a variable associated with increased disease risk. Understanding the role of risk factors is significant for developing a strategy to improve global health. There is strong evidence that risk factors like smoking, alcohol consumption, previous cataract surgery, age, high-density lipoprotein (HDL) cholesterol, BMI, female gender, and focal hyper-pigmentation are independently associated with age-related macular degeneration (AMD). Currently, in the literature, statistical techniques like logistic regression, multivariable logistic regression, etc., are being used to identify AMD risk factors by employing numerical/categorical data. However, artificial intelligence (AI) techniques have not been used so far in the literature for identifying risk factors for AMD. On the other hand, artificial intelligence (AI) based tools can anticipate when a person is at risk of developing chronic diseases like cancer, dementia, asthma, etc., in providing personalized care. AI-based techniques can employ numerical/categorical and/or image data thus resulting in multimodal data analysis, which provides the need for AI-based tools to be used for risk factor analysis in ophthalmology. This review summarizes the statistical techniques used to identify various risk factors and the higher benefits that AI techniques provide for AMD-related disease prediction. Additional studies are required to review different techniques for risk factor identification for other ophthalmic diseases like glaucoma, diabetic macular edema, retinopathy of prematurity, cataract, and diabetic retinopathy.

Age-Related Macular Degeneration and Cardiovascular Diseases: Revisiting the Common Soil Theory

ABSTRACT

Age-related macular degeneration (AMD), a complex disease associated with aging, remains one of the leading causes of visual loss in high-income countries and its prevalence is expected to increase over the next decades. Polypoidal choroidal vasculopathy has been considered a variant of neovascular AMD and is highly prevalent in Asian populations. Similarly, cardiovascular disease (CVD)-another complex disease associated with aging-is a leading cause of morbidity and mortality in high-income countries and its prevalence is also expected to increase due to population aging. Previous studies reported an increased risk for CVD in AMD patients, indicating an underlying "common soil." Reviewing the current literature, consistent evidence for common risk factors and mutual comorbidity was identified for both diseases. Cardiovascular risk factors include smoking, diet, and low levels of physical activity, which also play a role in AMD pathogenesis. Several studies demonstrated AMD patients to be at higher risk for CVD compared to the general older population. The complexity of both diseases, however, complicates research on their relation, and thus studies ought to be interpreted with caution. Herein we present an overview of selected studies and their main "take-home messages" on this topic, and hypothesize on the patho-etiologic "common ground" of these 2 diseases.

Association between Patient-Reported Outcomes and Time to Late Age-Related Macular Degeneration in the Laser Intervention in Early Stages of Age-Related Macular Degeneration Study

PURPOSE

To investigate the relationship between patient-reported outcome (PRO) questionnaire responses and time to late age-related macular degeneration (AMD; neovascular AMD [nAMD] or multimodal imaging [MMI]-defined atrophy) among individuals with bilateral large drusen, and the prognostic value of baseline PROs for 36-month AMD status.

DESIGN

Exploratory analyses from a multicenter randomized controlled trial of an AMD intervention (Australian New Zealand Clinical Trials Registry identifier, ACTRN12612000704897).

PARTICIPANTS

Sham treatment group of the Laser Intervention in Early Stages of Age-Related Macular Degeneration (LEAD) Study (n = 141; age, 50-88 years; 77% female).

METHODS

The 28-item Impact of Vision Impairment (IVI-28) and 10-item Night Vision Questionnaire (NVQ-10) were administered at the baseline visit. The PRO scores were derived using rating scale models. Multivariate Cox regression adjusting for demographics and clinical measures of vision (low-luminance visual acuity, low-luminance deficit, and microperimetric sensitivity) from the poorer-performing eye was used to investigate the association between PRO scores and time to late AMD in either eye. Multivariate competing-risk regression was used to estimate cause-specific subhazard ratios for nAMD and atrophy in either eye. Cross-validated logistic lasso models were used to estimate the predicted probability of AMD at 36 months. The area under the receiver operating characteristic curve was assessed to compare prognostic accuracy between models with and without PROs.

MAIN OUTCOME MEASURE

Time until nAMD or atrophy in either eye.

RESULTS

The PRO scores were skewed toward higher functional vision. Higher IVI-28 scores were associated with a lower risk of progression to MMI-defined atrophy (20 events: adjusted hazard ratio, 0.65/logit increase; P = 0.002) but not nAMD (10 events; P = 0.562). Insufficient evidence was found of an association between NVQ-10 score and rate of progression to late AMD (P ≥0.149). Baseline IVI-28 scores were found to contribute to the prognosis of atrophy at the 36-month visit (P = 0.010).

CONCLUSIONS

On average, PROs were associated with an increased risk of progression from intermediate AMD to MMI-defined atrophy. Continuing development of instruments to record PROs in the early stages of AMD have the potential to produce inexpensive and efficient tools to assist in the assessment of disease severity and risk of AMD progression.

A comparison of methods to estimate the survivor average causal effect in the presence of missing data: a simulation study

BACKGROUND

Attrition due to death and non-attendance are common sources of bias in studies of age-related diseases. A simulation study is presented to compare two methods for estimating the survivor average causal effect (SACE) of a binary exposure (sex-specific dietary iron intake) on a binary outcome (age-related macular degeneration, AMD) in this setting.

METHODS

A dataset of 10,000 participants was simulated 1200 times under each scenario with outcome data missing dependent on measured and unmeasured covariates and survival. Scenarios differed by the magnitude and direction of effect of an unmeasured confounder on both survival and the outcome, and whether participants who died following a protective exposure would also die if they had not received the exposure (validity of the monotonicity assumption). The performance of a marginal structural model (MSM, weighting for exposure, survival and missing data) was compared to a sensitivity approach for estimating the SACE. As an illustrative example, the SACE of iron intake on AMD was estimated using data from 39,918 participants of the Melbourne Collaborative Cohort Study.

RESULTS

The MSM approach tended to underestimate the true magnitude of effect when the unmeasured confounder had opposing directions of effect on survival and the outcome. Overestimation was observed when the unmeasured confounder had the same direction of effect on survival and the outcome. Violation of the monotonicity assumption did not increase bias. The estimates were similar between the MSM approach and the sensitivity approach assessed at the sensitivity parameter of 1 (assuming no survival bias). In the illustrative example, high iron intake was found to be protective of AMD (adjusted OR 0.57, 95% CI 0.40-0.82) using complete case analysis via traditional logistic regression. The adjusted SACE odds ratio did not differ substantially from the complete case estimate, ranging from 0.54 to 0.58 for each of the SACE methods.

CONCLUSIONS

On average, MSMs with weighting for exposure, missing data and survival produced biased estimates of the SACE in the presence of an unmeasured survival-outcome confounder. The direction and magnitude of effect of unmeasured survival-outcome confounders should be considered when assessing exposure-outcome associations in the presence of attrition due to death.

Incidence of and Risk Factors Associated With Age-Related Macular Degeneration: Four-Year Follow-up From the ALIENOR Study

Importance

While the prevalence of age-related macular degeneration (AMD) differs according to continents and races/ethnicities, its incidence in the European continent has been scarcely documented.

Objective

To describe the incidence and associated risk factors of AMD in elderly French individuals.

Design, Setting, and Participants

This population-based cohort study of 963 residents of Bordeaux, France, who were 73 years or older at baseline and participated in the Antioxydants, Lipides Essentiels, Nutrition et Maladies Oculaires (ALIENOR) Study between October 2, 2006, and December 21, 2012. Of 829 participants at risk for incident AMD, 659 (79.5%) were observed for a mean (SD) duration of 3.8 (1.1) years. Data were analyzed from August 2016 to March 2017.

Main Outcomes and Measures

Age-related macular degeneration was graded from retinal photographs and spectral-domain optical coherence tomography into 5 exclusive stages: no AMD, early AMD1, early AMD2, late atrophic AMD, and late neovascular AMD.

Results

Of the 659 eligible participants, 413 (62.7%) were women, and the mean (SD; range) age was 79.7 (4.4; 73-94) years. A total of 120 incident cases of early AMD and 45 incident cases of advanced AMD were recorded. Incidence rates of early and advanced AMD were 79.9 (95% CI, 66.8-95.5) per 1000 person-years and 18.6 (95% CI, 13.9-24.9) per 1000 person-years, respectively, corresponding to 5-year risks of 32.9% and 8.9%. Incidence of advanced AMD per 1000 eye-years was 1.5 in eyes without any AMD at baseline, 42.4 in those with early AMD1, and 85.1 in those with early AMD2. In multivariate analysis without correction for multiple testing, progression from early to advanced AMD was associated with AMD grade in the fellow eye (hazard ratio [HR] according to grade, 13.0 [95% CI, 2.8-61.2] to 22.5 [95% CI, 2.6-195.9]), having smoked at least 20 pack-years (calculated as number of smoking years × mean number of cigarettes per day / 20; HR, 3.0; 95% CI, 1.4-6.5), and complement factor H (CFH) Y402H genotype (CC genotype: HR, 2.3; 95% CI, 1.0-5.3; TC genotype: HR, 1.5; 95% CI, 0.6-3.7). Incidence of early AMD was associated with early AMD in the fellow eye (early AMD1: HR, 2.6; 95% CI, 1.6-4.2; early AMD2: HR, 5.6; 95% CI, 3.3-9.4) and high plasma high-density lipoprotein cholesterol levels (HR, 1.2; 95% CI, 1.0-1.4).

Conclusions and Relevance

In this cohort, AMD incidence rates were similar to those observed in other European populations. This study suggests a high risk for incident early AMD in individuals with high plasma high-density lipoprotein cholesterol levels while confirming the high risk for progression from early to advanced AMD in heavy smokers and carriers of CFH Y402H at-risk genotypes.

A Nationwide Cohort Study on the Association Between Past Physical Activity and Neovascular Age-Related Macular Degeneration in an East Asian Population

Importance

It has been suggested that physical activity (PA) is associated with reduced risk for early age-related macular degeneration (AMD). Systematic evaluation has been examining the association between lifestyle and neovascular AMD in an East Asian population, with a particular focus on past vigorous PA.

Objective

To investigate the association between neovascular AMD and past PA, particularly a history of vigorous exercise, in the overall study population and among 2 a priori-defined subgroups.

Design, Setting, and Participants

In this propensity score-matched cohort study, individuals between ages 45 and 79 years who were included in the South Korean National Health Insurance Service database from 2002 through 2013 were evaluated. Physical activity and incident neovascular AMD were recorded at baseline (2002-2003) and at follow-up (August 1, 2009, to December 31, 2013), respectively. Using a 1:1 propensity score-matched analysis, the incidence of neovascular AMD was compared using hazard ratios (HRs) for neovascular AMD between 105 980 participants who did and 105 980 who did not (no-PA) engage in vigorous PA. The data analysis was performed from April 19, 2017, to June 5, 2017.

Exposures

Physical activity.

Main Outcomes and Measures

Incident cases of neovascular AMD.

Results

Of the 211 960 participants (92 036 [43.4%] women; mean [SD] age, 55.1 [7.8] years), neovascular AMD was detected at follow-up in 250 (0.24%) individuals who engaged in past vigorous PA and in 198 (0.19%) of those who did not (HR, 1.23; 95% CI, 1.02-1.49). In subgroup analysis, vigorous PA was associated with a greater HR for neovascular AMD in participants aged 45 to 64 years (HR, 1.30; 95% CI, 1.04-1.63) and in men (HR, 1.36; 95% CI, 1.09-1.69). In the high-PA (≥5 times/wk: HR, 1.54; 95% CI, 1.15-2.06) and moderate-PA (1-4 times/wk: HR, 1.28; 95% CI, 1.01-1.63) groups, there was a greater incidence of neovascular AMD in the vigorous PA than in the no-PA group for men; no association was found for women.

Conclusions and Relevance

Self-reported past vigorous PA in men aged 45 to 64 years was associated with an increased risk for neovascular AMD. To our knowledge, no previous study has reported such an association; replication of the results would seem warranted to strengthen the likelihood of a cause and effect relationship.

Physical Activity and Age-related Macular Degeneration: A Systematic Literature Review and Meta-analysis

PURPOSE

To better understand the association, in a white population, of physical activity and age-related macular degeneration (AMD)-the main cause of irreversible severe vision loss in developed countries-given the suggestion that a healthy lifestyle may assist in delaying the onset and progression of AMD.

DESIGN

Systematic review and meta-analysis.

METHODS

Medline, EMBASE, and Google Scholar were systematically searched for studies up to May 2015. Reference lists of published articles were hand searched and study authors were contacted to provide additional data. Those in the lowest category of activity in each study were compared with all other participants to assess the association between physical activity and both early and late AMD using random-effects meta-analysis.

RESULTS

Nine studies (subject age range 30-97 years) were included in the meta-analysis. Physical activity was found to have a protective association with both early AMD (8 studies, n = 38 112, odds ratio (OR) 0.92, 95% confidence interval [CI] 0.86-0.98) and late AMD (7 studies, n = 28 854, OR 0.59, 95% CI 0.49-0.72).

CONCLUSIONS

Physical activity is associated with lower odds of early and late AMD in white populations. These findings have important implications, reinforcing the public health message of staying active throughout life. However, further longitudinal studies are required to confirm and further characterize a protective effect of physical activity on the onset and/or progression of AMD.

Prevalence of Age-Related Macular Degeneration in Europe: The Past and the Future

Purpose

Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD in Europe from 1990 to 2013 using the European Eye Epidemiology (E3) consortium, and made projections for the future.

Design

Meta-analysis of prevalence data.

Participants

A total of 42 080 individuals 40 years of age and older participating in 14 population-based cohorts from 10 countries in Europe.

Methods

AMD was diagnosed based on fundus photographs using the Rotterdam Classification. Prevalence of early and late AMD was calculated using random-effects meta-analysis stratified for age, birth cohort, gender, geographic region, and time period of the study. Best-corrected visual acuity (BCVA) was compared between late AMD subtypes; geographic atrophy (GA) and choroidal neovascularization (CNV).

Main Outcome Measures

Prevalence of early and late AMD, BCVA, and number of AMD cases.

Results

Prevalence of early AMD increased from 3.5% (95% confidence interval [CI] 2.1%–5.0%) in those aged 55–59 years to 17.6% (95% CI 13.6%–21.5%) in those aged ≥85 years; for late AMD these figures were 0.1% (95% CI 0.04%–0.3%) and 9.8% (95% CI 6.3%–13.3%), respectively. We observed a decreasing prevalence of late AMD after 2006, which became most prominent after age 70. Prevalences were similar for gender across all age groups except for late AMD in the oldest age category, and a trend was found showing a higher prevalence of CNV in Northern Europe. After 2006, fewer eyes and fewer ≥80-year-old subjects with CNV were visually impaired (P = 0.016). Projections of AMD showed an almost doubling of affected persons despite a decreasing prevalence. By 2040, the number of individuals in Europe with early AMD will range between 14.9 and 21.5 million, and for late AMD between 3.9 and 4.8 million.

Conclusion

We observed a decreasing prevalence of AMD and an improvement in visual acuity in CNV occuring over the past 2 decades in Europe. Healthier lifestyles and implementation of anti–vascular endothelial growth factor treatment are the most likely explanations. Nevertheless, the numbers of affected subjects will increase considerably in the next 2 decades. AMD continues to remain a significant public health problem among Europeans.