Ryan Livingston joined the MJH Life Sciences team in March of 2025, shortly after graduating from TCNJ with a bachelor’s degree in English. He enjoys creative writing, reading, and scuba diving. He can be reached at rlivingston@mjhlifesciences.com.

Ryan Livingston

A recent prospective cohort study conducted in Hong Kong revealed a substantial linkage between simultaneous exposure to multiple air pollutants and 

“Given that individuals are exposed to a complex mixture of air pollutants and that high collinearity exists among different pollutants, estimating the combined effect of multiple air pollutants on human health is essential,” wrote Yingan Li, department of ophthalmology and visual sciences, Chinese University of Hong Kong, and colleagues.

The team collected information on more than 500,000 participants through the UK Biobank database; after excluding those with diagnoses prior to the study’s timeframe of 2006-2010, the total was narrowed down to 441,567 participants. These participants came from 22 different Biobank centers in England, Scotland, and Wales; 54.38% of participants were female and 45.62% were male. Of these, 55,104 were diagnosed with cataract, 11,940 with glaucoma, and 9060 with AMD over a follow-up period of 14.41 years.

Air pollutants accounted for in the study included nitrogen dioxide (NO

), nitrogen oxides (NO), and particulate matter below 2.5 μm (PM

). Mean annual pollutant concentrations were as follows:

To measure potential joint exposure risk, the team created air pollution scores for each individual disease by totaling the concentrations of the pollutants and deriving the multivariable-adjusted risk estimates (β coefficients) from the final model.

The hazard ratios (HRs) indicated that long-term exposure to any individual pollutant had a significant association with increased risk for cataract. Per interquartile range (IQR) increment, the HRs were 1.06 (95% CI, 1.05-1.07) for PM

, and 1.03 (95% CI, 1.02-1.04) for NO (all 

 <.05). Notably, there was no significant association between cataract incidence and PM

. Glaucoma and AMD exhibited significantly higher risk after exposure to PM

, and NO, while no significant connection was seen for PM

The team then utilized the weighted air pollution score of all 5 pollutants; results indicated that the risk of a given disease increased by 4-5% for each IQR increment in air pollution score. For cataract, HR 1.05 (95% CI, 1.04-1.06); glaucoma, 1.04 (95% CI, 1.02-1.06); AMD (95% CI, 1.04-1.07) (all 

<.05). The highest quartile of air pollution score exhibited HRs of 1.13 (95% CI, 1.1-1.16) for cataract, 1.09 (95% CI, 1.03-1.15) for glaucoma, and 1.14 (95% CI, 1.07-1.22) for AMD (all 

<.05) when compared to the lowest quartile. Li and colleagues suggest that these data present additive effects of exposure to potential mixtures.

A nonlinear association was observed between air pollution score and both AMD and cataract; risk increased sharply at low pollutant concentrations, but began to slow as pollution levels rose, even declining in some instances. The team suspects this is the result of individuals seeking medical attention or altering lifestyles to avoid worsening air quality.

One of the primary limitations of the study, as explicitly mentioned by Li and colleagues, is the limited data available on common pollutants. Carbon monoxide, sulfur dioxide, and other trace elements were not listed in the UK Biobank, which leaves the study with a smaller pool of contaminants to test. This limitation may result in similarly dangerous contaminants going unnoticed.

Historically, data regarding combinations of air pollutants and the corresponding prevalence of eye disease have been lacking. There is no existing metric for measuring combinations of air pollutants.

 Li and colleagues enacted this study with the goal of highlighting the necessity for a set system of calculating air pollutants’ cumulative effects.

“Considering that many countries’ air quality standards are still well above the WHO Global Air Quality Guidelines in 2005, the findings suggest that stricter standards or regulations for air pollution control should be implemented in the future policy, making to alleviate the disease burden of cataract, glaucoma and AMD,” wrote Li and colleagues.

Li Y, Zhang Y, Kam KW, et al. Associations of long-term joint exposure to multiple ambient air pollutants with the incidence of age-related eye diseases. 

. 2025;294:118052. doi:10.1016/j.ecoenv.2025.118052

Oakes M, Baxter L, Long TC. Evaluating the application of multipollutant exposure metrics in Air Pollution Health Studies. 

. 2014;69:90-99. doi:10.1016/j.envint.2014.03.030

Articles

A prospective cohort study in Hong Kong linked exposure to multiple air pollutants with increased incidence of age-related eye diseases, such as cataract, glaucoma, and AMD. The study analyzed data from over 441,000 participants, focusing on pollutants like NO2, NO, and PM2.5. Results showed significant associations between pollutant exposure and eye disease risk, with hazard ratios indicating increased risk per interquartile range increment. The study highlighted the need for stricter air quality standards and a system to measure cumulative pollutant effects, despite limitations in pollutant data availability.

The study proves that cataract, glaucoma, and age-related eye disease can be exacerbated by exposure to several common pollutants simultaneously.

Joint Air Pollutant Exposure Linked to Eye Disease

A recent prospective, mixed-methods cohort study in Amsterdam indicated overall improvement in physical, mental, and social health after non-myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) to treat 

“The findings of our study are relevant to a large and growing number of SCD patients, as HSCT is increasingly considered in adults with SCD,” wrote Elisabeth Dovern, of the department of hematology at Amsterdam UMC, and colleagues.

 “Psychosocial support throughout the transplant journey is essential for patients to cope with the [post-]transplant challenges and the altered reality and opportunities that follow curative therapy.”

The study examined a total of 17 participants, each ≥ 16 years of age, who were planning to undergo HSCT. Of the participants, 7 were female, 10 were male, 8 had undergone haploidentical donor HSCT, and 9 underwent matched sibling donor HSCT.

The team collected 9 Patient-Reported Outcomes Measurement Information System (PROMIS®) measures for all 17 participants at baseline, as well as 6, 12, and 18 months post-transplant. These measures were categorized as follows:

Physical health, including pain interference, physical function, fatigue, and sleep disturbance

Mental health, including anxiety, anger, and depression

Social health, including ability to participate in and satisfaction with social roles

-scores and compared them against general population values.

Additionally, they conducted 2 semi-structured interviews with each of the first 10 participants. The first took place before the start of preconditioning, and the second roughly 12-18 months post-transplant. All participants had successfully engrafted and either stopped or were stopping immunosuppressive agents at time of interview.

Initial results indicated worse measurements in all 3 PROMIS® subcategories pre-transplant when compared to population measures. The first round of interviews reflected this, with participants reporting depression, anxiety, and a lack of physical capability. However, investigators noted a substantial improvement was seen across the board after treatment, with several values matching that of the general population. By the 18-month measurement, most participants exhibited 

The team noted no significant difference in PROMIS® score improvements between matched sibling donor and haploidentical donor transplant recipients. Investigators suggested that the different conditioning methods do not have a significant impact on quality-of-life improvement. However, they also note that these findings require a larger patient cohort to verify.

Physical health outcomes exhibited improvement 6 months post-transplant, which investigators believe is due to normalization of hemoglobin values and resolution of SCD-related vaso-occlusive events. At 18 months, pain interference (

<.001) were above the average population, while sleep disturbance (

 = .052) were roughly even with average measurements. Likewise, qualitative results indicated a sharp improvement in quality of life; in the second round of interviews, participants reported an increased capacity for physical activity and lower need for sleep.

values exhibited a more gradual and less pronounced increase post-transplant. After 18 months, anxiety (

 = .025) were slightly above population measurements. Interviews revealed various mental health challenges during the first year, such as the fear of SCD returning. The team also indicated potential negative side effects to the transplant as a source of anxiety.

Investigators suggested the “burden of normality”, or the struggle to adjust to a symptomless life after treatment, as another plausible explanation

 Although this has not yet been directly documented for patients with SCD, investigators believe it to be a partial cause for the lower mental health measurements.

values remained relatively low after surgery, rising above the general population only after 18 months (both 

 <.001). The team believes is a result of lifestyle restrictions due to immunosuppressive therapy. The interviews also revealed some disappointment with social interactions before and during the transplant process.

Given the significant differences in all PROMIS® categories from pre- to post-operation and the variance in interview responses, Dovern and colleagues point out that the results underscore the importance of providing support for patients entering the curative process.

“The effects of HSCT on mental health are more complex and include many positive effects as well as difficulties with adjustment and processing the psychological aftermath of SCD,” wrote Dovern and colleagues.

 “Incorporation of psychosocial care and patient-reported outcome measures into the treatment plan of SCD patients undergoing HSCT is needed to improve the transplant outcomes and patient experience.”

Dovern E, Nijland SJ, Braamse AM, et al. Changes in the quality of life of adults with sickle cell disease following allogeneic stem cell transplantation: A mixed‐methods, prospective Cohort Study. 

Baas L, van der Graaf R, van Hoorn ES, Bredenoord AL, Meijer K. The ethics of gene therapy for hemophilia: A narrative review. 

. 2023;21(3):413-420. doi:10.1016/j.jtha.2022.12.027

A prospective cohort study in Amsterdam evaluated the impact of non-myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) on adults with sickle cell disease (SCD). The study found significant improvements in physical, mental, and social health post-transplant, with physical health showing the most rapid enhancement. Mental health improvements were more gradual, with some patients experiencing adjustment challenges. Social health improvements were delayed, likely due to lifestyle restrictions. The study emphasizes the importance of psychosocial support and patient-reported outcome measures to enhance transplant outcomes and patient experiences.

Patient-reported outcome measures display positive trends after hematopoietic stem cell transplantation for patients with sickle cell disease.

Stem Cell Transplant as Cure for Sickle Cell Disease Improves Quality of Life

A recent cross-sectional study has identified a significant positive correlation between weight-adjusted waist index and risk of 

The study, conducted in Fujian, China, collated data from the National Health and Nutrition Examination Survey (NHANES) in order to establish the weight-adjusted waist index's predictive capabilities for AMD and its potential superiority to existing measures such as body mass index (BMI).

“The research underscores the potential of the [index] as a reliable predictive biomarker for AMD, with spline smoothing analyses confirming a non-linear positive relationship between the [index] and AMD prevalence,” writes Yuting Wu, Department of Ophthalmology, Affiliated People’s Hospital, and colleagues.

The team pulled data on 20,497 participants from NHANES from 2005 to 2008; after excluding participants younger than 40 years, those with missing data on waist circumference (WC) or weight, and those missing other relevant data, the study was narrowed down to 5132 participants. Among the population, 50.16% of participants were female and 49.84% were male.

Individuals within the 2005-2008 NHANES cycle underwent retinal photography. AMD was diagnosed based on distinctive characteristics of the fundus, going by standard classification.

Weight-adjusted waist index measurements were calculated by dividing WC by the square root of weight in kilograms. Data were then categorized into tertiles; Tertile 1 (8.59-10.85), Tertile 2 (10.85-11.52), and Tertile 3 (11.52-15.70). Tertile 3 exhibited a substantially greater risk of AMD, measured at 1.9 times greater than Tertile 1 (odds ratio [OR], 2.90, 95% CI 2.18-3.86; 

 <.0001). Higher proportions of weight, BMI, and WC were connected to higher weight-adjusted waist index tertiles, as well as a higher likelihood of diabetes, hypertension, and AMD.

The study revealed that each individual unit increase in the index raised that participant’s chances of having AMD by as high as 76%. Threshold effect analyses highlighted a turning point of around 12.11 in the general population. Below this threshold, a substantial positive increase was observed in AMD (OR 1.50, 95% CI, 1.04-2.16; 

 =.0300). Above it, there was no significant increase in AMD (OR 0.75, 95% CI, 0.39-1.45; 

The predictive capacity of the index for AMD was tested through receiver operating characteristic (ROC) curve analysis. Results were compared against other commonly used obesity assessment indicators. To measure AMD incidence reporting, the team utilized area under the curve (AUC) values: weight-adjusted waist index, 0.625; weight, 0.560; BMI, 0.530; and WC, 0.508.

Coupled with a positive association between the weight-adjusted waist index and risk of AMD (OR = 1.76 1.52, 2.04; 

<0.0001), these findings indicate that the index has a substantially greater ability to indicate AMD risk when compared to WC, weight, and BMI. Wu and colleagues suggest that the index is therefore a more reliable indicator of potential AMD in adults aged ≥40 years.

While BMI data is simpler to collect, its diagnostic performance can decrease with an individual’s age, with difficulty distinguishing between fat and muscle mass. A given BMI cutoff has been shown to miss more than half of people with excess fat.

Wu and colleagues noted that the utilization of BMI as an indicator of AMD and other obesity-related diseases has resulted in the “obesity paradox”, which suggests that individuals with obesity may have more positive prognoses than the average-weight population. However, they indicate that the weight-adjusted waist index is more capable of accounting for both adipose tissue and subcutaneous fat, which are occasionally missed by other tests.

“These findings emphasize the significance of early prediction and intervention for AMD in the general population,” writes Wu and colleagues. “Nonetheless, future research should prioritize investigating diverse racial groups, conducting longitudinal studies to establish cause-and-effect relationships, and potentially utilizing intelligent ophthalmology (IO) technology to explore molecular mechanisms in greater depth, as the pathophysiology of AMD warrants further exploration.”

Wu Y, Liu Y, Jiao Z, et al. Association between the weight-adjusted waist index and age-related macular degeneration in US adults aged≥40 years: The NHANES 2005–2008. 

Romero-Corral A, Somers VK, Sierra-Johnson J, et al. Accuracy of body mass index in diagnosing obesity in the adult general population. 

. 2008;32(6):959-966. doi:10.1038/ijo.2008.11

A cross-sectional study in Fujian, China, has identified a significant correlation between the weight-adjusted waist index and the risk of age-related macular degeneration (AMD). The study analyzed data from the NHANES, focusing on adults aged 40 and above, and found that the weight-adjusted waist index is a more reliable predictor of AMD risk compared to traditional measures like BMI. The index accounts for both adipose and subcutaneous fat, offering a more comprehensive assessment. Future research should explore diverse populations and investigate the underlying molecular mechanisms of AMD.

Study finds positive association between weight-adjusted waist index and risk of age-related macular degeneration in adults aged 40 or over.

Weight-Adjusted Waist Index Successfully Predicts Macular Degeneration

A recent population-based cross-sectional study examining all primary schools in Hong Kong’s Education Bureau revealed a substantial increase in prevalence and severity of 

Ka Wai Kam, MSc, University of Hong Kong, and colleagues examined 9 years of data from 2015-2023, covering the pre-, mid-, and post-pandemic periods (2015-19, 2020, and 2021-23, respectively). Children aged 6-8 years underwent ocular exams, and parents completed questionnaires regarding lifestyle and environmental risk factors.

“Given the high prevalence of astigmatism, the potential impact of higher degrees of astigmatism may warrant dedicated efforts to elucidate the relationship between environmental and/or lifestyle factors, as well as the pathophysiology of astigmatism, in order to preserve children’s eyesight and quality of life,” Kam and colleagues wrote.

The study was initially proposed in response to evidence of increased rates of myopia among schoolchildren. Astigmatism’s direct connection to myopia is well documented, and the latter rose sharply in children at the beginning of the COVID-19 pandemic, when lockdown measures were implemented.

Investigators took a randomized sampling frame by stratifying all primary schools registered with the Education Bureau into 7 main groups. Potential participants with ocular trauma or congenital ocular diseases were excluded. In total, the study examined 21655 children: 11464 (52.9%) boys and 10191 (47.1%) girls.

Examinations were conducted with an autorefractor after a cycloplegic regimen. At least two cycles of eye drops were administered, followed by two drops of cyclopentolate, 1% and tropicamide, 1% at five minutes apart during the first cycle, ten minutes after the second, and 30 minutes after the second if pupil size was less than 6.0 mm or the pupillary light reflex was still present. Flattest keratometry (K1) and steepest keratometry (K2) were measured with a noncontact partial-coherence laser interferometry.

Before the COVID-19 pandemic in Hong Kong, the prevalence of refractive astigmatism (RA) of at least 1.0 diopter (D) was 21.4%. The data revealed that, during COVID-19, RA prevalence increased to 24.6% (difference, 1.1%; 95% CI, -1.4% to 3.7%). After restrictions were removed, prevalence continued to increase up to 30% (difference, 6.5%; 95% CI, 4.7% to 8.3%) in 2021 and 34.7% (difference, 11.2%; 95% CI, 8.2% to 14.3%) in 2022-2023.

The prevalence of corneal astigmatism (CA) of at least 1.0 D in children was 59.7% pre-COVID-19. Kam and colleagues discovered an increase up to 66.9% (difference, 7.2%; 95% CI, 5.3%-9.1%) in 2021 that was maintained at 64.7% (difference, 5.0%; 95% CI, 1.8%-8.1%) in 2022-23. Again, a consistent increase was exhibited across all subgroups. A 20% increase to risk of RA (odds ratio [OR] 1.20; 95% CI, 1.09-1.33; 

 <0.001) and a 26% increase to risk of CA (OR, 1.26; 95% CI, 1.15-1.38; 

 <0.001) were associated with the pandemic.

The pandemic was also linked to a 0.04 D increase in the magnitude of RA (95% CI, 0.02-0.07; 

 < .001), and 0.05 D in the magnitude of CA (95% CI, 0.02-0.08; 

Additionally, results indicated a K1 decrease from 42.91 D in 2015-19 to 42.85 D in 2022-23 (difference, -0.06 D; 95% CI, -0.15 to 0.03 D), while K2 values increased from 44.15 D in 2015-19 to 44.2 D in 2021-23. Investigators indicated that increasing astigmatism resulted in steeper corneal curvature located almost entirely within the vertical meridian. The team suggests that these changes may explain some of the progression of CA.

Both myopia and astigmatism can be directly connected to screen usage and near-work. Notably, restrictions put in place by the pandemic resulted in a switch from in-person to virtual classes, which required children to spend longer hours viewing electronic devices and engaging in intensive near work.

“Based on the previous reports that astigmatism and myopia are highly correlated and that astigmatism may be a byproduct of myopia, the findings in our present study provided additional data on the corneal component, which is a major contributor to RA. We think that the change in corneal curvatures induced by near work takes time to develop.”

Kam KW, Shing E, Zhang Y, et al. Prevalence and severity of astigmatism in children after COVID-19. 

. Published online March 20, 2025. doi:10.1001/jamaophthalmol.2025.0205

Zhang XJ, Zhang Y, Kam KW, et al. Prevalence of myopia in children before, during, and after covid-19 restrictions in Hong Kong. 

. 2023;6(3). doi:10.1001/jamanetworkopen.2023.4080

A population-based study in Hong Kong revealed a significant rise in refractive and corneal astigmatism among children aged 6 to 8 during and after the COVID-19 pandemic. The study analyzed data from 2015 to 2023, showing increased prevalence and severity of astigmatism, likely linked to increased screen time and near-work due to pandemic restrictions. The findings suggest a need to explore environmental and lifestyle factors affecting astigmatism. The study highlights the correlation between astigmatism and myopia, emphasizing the impact of altered corneal curvature on astigmatism progression.

Hong Kong schoolchildren exhibit increased rates of refractory and corneal astigmatism due to screen exposure during lockdown.