Abstract
Objectives
Major ocular diseases share common risk factors and pathogeneses with stroke. This study aimed to evaluate the relation between stroke and ocular diseases including visual impairment (VI).
Methods
The cross-sectional study investigated the prevalence and associations of VI and major eye diseases with stroke among 4570 participants in the 2005–2008 National Health and Nutrition Examination Survey (NHANES). The association of VI and major ocular diseases with stroke were estimated using univariate and multivariate logistic regression crude models and models adjusted for demographics and clinical factors. We also conducted stratified analyses by diabetes and hypertension status.
Results
VI was associated with stroke, and the odds ratios (ORs) for mild and moderate and severe visual impairment (MSVI) were 6.79 (95% confidence interval (CI): 2.44–18.88) and 9.46 (95% CI: 2.19–40.94) after adjusting for age and gender (all P < 0.05). Ocular disease was associated with stroke with OR reaching 5.54 (95% CI: 1.83–16.74), and the OR was 9.61 (95% CI: 3.05–30.23) for stroke patients suffering DR after adjusting for age and gender (all P < 0.05). After multivariable adjustment, the associations were limited to mild VI (OR = 10.00, 95% CI: 3.16–30.58), MSVI (OR = 8.57, 95% CI: 1.58–43.36), and any ocular disease (OR = 5.18, 95% CI: 1.46–18.42) (all P < 0.05). Significant associations between stroke and any ocular disease and DR were observed among diabetic participants, and significant relation between stroke and MSVI was found among hypertension patients.
Conclusions
The sample of the US population demonstrates significant associations between VI and major ocular disease with stroke.
Subject terms: Risk factors, Eye diseases
Introduction
Stroke is a leading cause of mortality and disability worldwide and it costs substantial economic lost on post-stroke care [1]. According to the Global Burden of Diseases (GBD) 2015 study, although the age-standardized death rates and prevalence of stroke have decreased in developed countries, the overall burden of stroke has reminded high [2]. In the United States, stroke affects 800,000 people and costs $34.3 billion annually [3]. The leading causes of nonrefractive VI in the US elderly are cataract, AMD, glaucoma, and diabetic retinopathy [4]. Since the eyes have the same arterial blood supply with the brain, and the retina and the optic nerve are of neuroectodermal origin, major cerebral diseases such as stroke may be associated with ocular diseases, especially the optic nerve and retina disorders. Visual impairment is mainly caused by retinal ischemia in approximately 16% of the stroke patients [5–7], which has negatively effects on rehabilitation, functional recovery and quality of life among stroke survivors [8]. It has been estimated about 92% of the stroke patients have visual impairment, and 20.5% display persistent VI at 90 days [9]. Previous studies have found associations between stroke with VI, cataract, AMD, glaucoma, and DR. Meanwhile, more evidence has supported that qualitative retinal microvascular abnormalities are risk factors for stroke [10]. Furthermore, the risk factors for stroke, such as age, gender, diabetes, hypertension, and other systematic diseases are similar in ocular diseases and VI.
However, to our knowledge, there have been no large, cross-sectional studies investigating the associations of VI, major ocular diseases with stroke in a nationally representative sample of the US adults. Therefore, we explored the prevalence and associations of VI and major ocular diseases with stroke in order to understand whether true links exist between stroke and eye health conditions, which may promote the development of new screening methods and therapeutic strategies for both conditions.
Methods
Study population
The Center for Disease Control and Prevention (CDC) National Health and Nutrition Exanimation Surveys (NHANES) is a series of national, population-based, cross-sectional surveys, which was conducted by the National Center for Health Statistics. The NHANES study collected health information from a representative sample of the US population through interviews, medical examinations, and lab tests. Findings from the surveys were used to investigate the prevalence and risk factors of major diseases to develop better public health policy. It was also used to expand the health knowledge for the nation [11].
In this study, we used publicly available NHANES survey data from the 2005–2006 and 2007–2008 cycles with a total of 20,497 participants. During the 2005–2008 phase of NHANES, retinal images were collected among 6797 participants who were 40 years or older. A total of 5371 participants had gradable retinal photographs and 4570 of them had complete stroke information and eye diseases medical records. We excluded the participants without complete medical information (Fig. 1). The survey years were selected because diagnoses of ocular diseases were evaluated subjectively via self-report and objective tests such as perimetric testing (N30–5 FDT, Carl Zeiss Meditec, Inc, Dublin, California), retinal photographs, and optic nerve head assessment.
Fig. 1.
Cohort selection process for the National Health and Nutrition Examination Survey (NHANES) 2005–2008.
The protocols of NHANES were approved by the institutional review board of the National Center for Health Statistics, Centers for Disease Control and Prevention (CDC). Written informed consent was obtained from each participant before participation in this study [12]. According to Human Subjects Regulations, Institutional Review Board reviews are not required when using the NHANES dataset [13].
Assessment of stroke
In NHANES, participants were asked, “Has a doctor or other health professional ever told you that you had a stroke?” The self-reported measures of stroke were reasonably accurate in the United States general population and have been used in prior epidemiological studies using data from NHANES. Ischemic and haemorrhagic stroke were not differentiated in NHANES.
Assessment of visual acuity
The method for visual acuity assessment has been described in details before [14]. In NHANES, the presenting visual acuity of the participants was evaluated using an autorefractor (ARK-760, Nidek Co Ltd). No VI was defined as visual acuity ≥20/40, and mild VI was visual acuity <20/40 to ≥20/60, while moderate and severe visual impairment (MSVI) indicated visual acuity <20/60.
Assessment of major eye disease
Self-reported cataract surgery was determined by the question: “Have you ever had a cataract operation?” The self-reported measures of cataract were reasonably accurate in the United States given the wide cataract surgical coverage and low threshold level for cataract surgery [13–15].
In NHANES, nonmydriatic 45° digital photographs were obtained from both eyes of participants aged 40 years or older in 2005–2008. They were taken by the Canon Retinal Camera CR6–45NM (Canon, Tokyo, Japan) and were graded at the University of Wisconsin Ocular Epidemiologic Reading Center, Madison.
The main outcome of the retinopathy severity was “4 levels retinopathy severity, worse eye” according to the Early Treatment Diabetic Retinopathy Study (ETDRS) grading scheme [16]. The data in our study was recoded as binary levels: no retinopathy and retinopathy. Patients had retinopathy ware defined as those with mild non-proliferative retinopathy (NPR), moderate/severe NPR, and proliferative retinopathy. Diabetic retinopathy (DR) was determined by any signs of retinopathy on fundus photographs and diagnosis of diabetes mellitus.
Based on the modified Wisconsin Age-Related Maculopathy Grading Classification Scheme [17], the presence of soft drusen more than 500um in size or pigmentary abnormalities was defined as early AMD, whereas the presence of late AMD lesions, such as choroidal neovascularization, geographic atrophy, and/or subretinal fibrous scarring was defined as late AMD. The data in our work was recoded as binary levels: no AMD and AMD.
In NHANES, glaucoma was defined by the question: “Have you ever been told you had glaucoma or high pressure in eyes?” Cup-to-disc ratios ≥0.6 for each eye from photographs of the optic nerve was identified as disc-defined glaucoma. We defined glaucoma as a grading of probable or definite in at least one eye, or the patients who reported themselves with glaucoma.
The presence of any of the following ocular disease was categorized as “any ocular disease”: cataract, DR, AMD, and glaucoma.
Confounding variable
Potential confounding variables included age, gender, race/ethnicity (Mexican American, non-Hispanic Black, non-Hispanic White and other), education level (less than 9th grade, grades 9–12 and college or above), marital status (married, never married and previously married), and family poverty income ratio (PIR). Age was categorized by 10-year age groups as 40 to 49, 50 to 59, 60 to 69, and 70 years or older. The indicator for family income (poverty income ratio) was classified as below poverty line (<1.00) or at above poverty line (≥1.00). Other clinical measurements included body mass index, diabetes mellitus, glycated haemoglobin (HbA1c) level, hypertension, systolic blood pressure, diastolic blood pressure, and history of cardiovascular diseases including coronary heart disease and angina. Diabetes mellitus was defined as HbA1c ≥6.5%, and hypertension was defined as the systolic blood pressure ≥130 mmHg, or the diastolic blood pressure ≥80 mmHg, or the participants who regularly took drugs to control the blood pressure. Depression was measured using the Patient Health Questionnaire (PHQ-9), a nine-item screening tool that evaluated the frequency of depression, and responded to each item were summed, with 27 being the highest total possible score. The method had high sensitivity and specificity of 88% to detect cases of major depression, and a score of ≥10 was defined as depression [18]. Coronary heart disease and angina were defined through the question: “Has a doctor or other health professional ever told you that you had a coronary heart disease, or angina?” The self-reported measures of heart diseases were reasonably accurate in the United States general population.
Statistical analyses
The complex survey design was incorporated, and sampling weights were used to provide estimates that are representative of the US population. It is a number of people in the population represented by that sample person. We used NHANES cluster design variable (SDMVSTRA, SDMVPSU) and the medical examination weight WTMEC2YR for 2005–2008 cohort.
Baseline characteristics of the participants were examined to show the descriptive data using design-adjusted Rao–Scott Pearson χ2 for categorical variables and t test or analysis of variance for continuous variables when evaluating the distribution of these variables between participants having or not having stroke. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of stroke with visual impairment and ocular diseases. Statistical adjustments were made for age and gender in model 1 since age is the single most powerful non-modifiable predictor of both stroke and major eye disease. Model 2 was adjusted for age, gender, race/ethnicity, education, marital status, and PIR, because the sociodemographic factors were associated with ocular diseases in NHANES studies [19]. Additional adjustments for clinical measures such as hypertension, diabetes, depression, and heart diseases were also made in model 3 as they were potential cofounders. Stratified analyses were conducted among stroke patients with diabetes mellitus and hypertension with age and gender adjusted. Model a was additionally adjusted for HbA1c among patients with diabetes mellitus. All statistical analyses were performed using R Statistical Software (version 4.0.3; R Foundation for Statistical Computing, Vienna, Austria). P value less than 0.05 was considered statistically significant.
Results
We restricted our analyses to participants aged 40 years or older (n = 6797) in the 2005–2008 NHANES data. A total of 2227 participants were excluded because of missing information of stroke status or major eye diseases, so that 4570 participants remained in the present analyses including 207 (4.53%) stroke patients. The characteristics of participants according to stroke status were shown in Table 1. Participants with stroke had higher prevalence of mild or moderate to severe visual impairment than those without (44.40% vs 25.90%). Similarly, the prevalence of major eye diseases, including cataract (30.80% vs 13.40%), AMD (19.60% vs 7.20%), DR (26.60% vs 11.60%), and any ocular disease (94.40% vs 80.30%) were also higher in participants with stroke than those without (all P < 0.05). A greater proportion of participants classified as having stroke were older, non-Hispanic, and had a high school education. Participants with stroke were more inclined to have diabetes, hypertension, depression, coronary heart disease and angina (all P < 0.05).
Table 1.
Participants characteristics according to the presence or absence of stroke.
| Stroke absence | Stroke Presence | P | |
|---|---|---|---|
| Number of participants | 6363 | 410 | |
| Age (%) | <0.001 | ||
| 40–49 | 1699 (26.70) | 37 (9.00) | |
| 50–59 | 1477 (23.20) | 43 (10.50) | |
| 60–69 | 1505 (23.70) | 112 (27.30) | |
| ≥70 | 1682 (26.40) | 218 (53.20) | |
| Gender, Female (%) | 3203 (50.03) | 211 (51.50) | 0.696 |
| Race/Ethnicity (%) | <0.001 | ||
| Mexican American | 1007 (15.80) | 39 (9.50) | |
| Non-Hispanic Black | 1356 (21.30) | 112 (27.30) | |
| Non-Hispanic White | 3293 (51.80) | 235 (57.30) | |
| Other | 707 (11.10) | 24 (5.90) | |
| BMI (mean (SD)) | 29.21 (6.53) | 29.82 (6.18) | 0.045 |
| DBP (mean (SD)) | 71.25 (12.62) | 68.99 (14.87) | 0.001 |
| SBP (mean (SD)) | 129.01 (20.26) | 135.76 (23.35) | 0.001 |
| HbA1c (mean (SD)) | 5.85 (1.10) | 6.18 (1.30) | |
| Education (%) | <0.001 | ||
| College or above | 2871 (46.00) | 137 (34.10) | |
| Grades 9–12 | 2507 (40.20) | 189 (47.00) | |
| Less Than 9th Grade | 859 (13.80) | 76 (18.90) | |
| PIR | 0.007 | ||
| ≥1 | 4919 (83.70) | 292 (78.3) | |
| <1 | 955 (15.00) | 81 (19.76) | |
| Marital status (%) | 0.01 | ||
| Married | 3991 (62.80) | 212 (51.70) | |
| Never married | 452 (7.10) | 23 (5.60) | |
| Previously married | 1914 (30.10) | 175 (42.70) | |
| Diabetes (%) | 842 (13.90) | 96 (25.10) | <0.001 |
| Coronary heart disease (%) | 344 (5.40) | 69 (17.20) | <0.001 |
| Angina (%) | 244 (3.80) | 51 (12.60) | <0.001 |
| Hypertension (%) | 1788 (28.90) | 176 (44.00) | <0.001 |
| Depression (%) | 454 (7.90) | 53 (15.30) | <0.001 |
| Visual Impairment (VI) (%) | <0.001 | ||
| No | 4386 (74.10) | 191 (55.50) | |
| mild | 965 (16.30) | 92 (26.70) | |
| MSVI | 566 (9.60) | 61 (17.70) | |
| Cataract (%) | 855 (13.40) | 126 (30.80) | <0.001 |
| AMD (%) | 382 (7.20) | 56 (19.60) | <0.001 |
| DR (%) | 627 (11.60) | 81 (26.60) | <0.001 |
| Glaucoma (%) | 109 (16.00) | 5 (13.50) | 0.866 |
| Any ocular diseases (%) | 1669 (80.30) | 204 (94.90) | <0.001 |
Data was weighted estimates and expressed as mean (standard error) or percentage (%).
BMI body mass index, DBP diastolic blood pressure, SBP systolic blood pressure, PIR poverty income ratio, MSVI moderate and severe visual impairment, DR diabetic retinopathy, AMD age-related macular degeneration.
The univariable logistic regression models investigated associations of VI, major eye diseases and other demographic factors with stroke. It has been revealed that the following factors were significantly associated with the presence of stroke, including lower education levels less than 9th Grades (OR = 4.49, 95% CI: 1.12–17.98), coronary heart disease (OR = 10.15, 95% CI: 3.62–28.50), angina (OR = 4.80, 95% CI: 1.05–21.97) (all P < 0.05). Major eye diseases were all risk factors for stroke, and the odds ratios (ORs) for mild and MSVI were 7.04 (95% CI: 2.50–19.86) and 11.60 (95% CI: 2.97–45.31), respectively (all P < 0.05). Any ocular disease is a great risk factor for stroke with OR reached 6.88 (95% CI: 2.67–17.76), and the ORs for other major eye diseases were as followed: DR, 8.61 (95% CI: 2.55–29.07); cataract, 3.75 (95% CI: 1.11–12.71); AMD, 2.19 (95% CI: 0.52–9.20), and glaucoma, 0.88 (95% CI: 0.24–3.21) (all P < 0.05) (Supplementary Table 1).
Table 2 showed the results of adjusted logistic regression models investigating associations of VI and major eye diseases with stroke. In model 1, participants with stroke were significantly associated with mild VI (OR = 6.79, 95% CI: 2.44–18.88), MSVI (OR = 9.46, 95% CI: 2.19–40.94), DR (OR = 9.61, 95% CI: 3.05–30.23) and any ocular disease (OR = 5.54, 95% CI: 1.83–16.74) after adjusting for age and gender (all P < 0.05). After adjusting for age, gender, race, educational levels, PIR, and marital status in model 2, the presence of stroke was significantly associated with mild visual impairment (OR = 7.31, 95% CI: 2.78–19.19), MSVI (OR = 9.31, 95% CI: 1.77–48.88), DR (OR = 9.96, 95% CI: 2.39–41.50), and any ocular diseases (OR = 5.52, 95% CI: 1.79–16.99) (all P < 0.05). After additionally adjusting for clinical measurements such as BMI, diastolic blood pressure, systolic blood pressure, diabetes, coronary heart disease, angina, hypertension and depression in model 3, the ORs of mild VI (OR = 10.00, 95% CI: 3.16–31.58), MSVI (OR = 8.57, 95% CI: 1.58–46.36), and any ocular diseases (OR = 5.18, 95% CI: 1.46–18.42) among participants with stroke increased ranging 5.18 to 10.00 folds (all P < 0.05), while the OR associated with cataract, glaucoma and DR were nonsignificant.
Table 2.
Association between visual impairment, major eye diseases, and stroke.
| Model 1b | Model 2c | Model 3d | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Ocular conditions | OR | 95% CI | P | OR | 95% CI | P | OR | 95% CI | P |
| Visual impairment | |||||||||
| Mild | 6.79 | [2.44–18.88] | 0.001 | 7.31 | [2.78–19.19] | <0.001 | 10.00 | [3.16–31.58] | 0.003 |
| MSVI | 9.46 | [2.19–40.94] | 0.01 | 9.31 | [1.77–48.88] | 0.02 | 8.57 | [1.58–46.36] | 0.03 |
| Cataract | 2.08 | [0.61–7.10] | 0.25 | 1.84 | [0.57–5.96] | 0.32 | 1.45 | [0.50–4.24] | 0.51 |
| Glaucoma | 0.46 | [0.14–1.54] | 0.22 | 0.51 | [0.16–1.64] | 0.27 | 0.49 | [0.10–2.46] | 0.40 |
| AMD | 1.53 | [0.33–7.03] | 0.59 | 1.57 | [0.40–6.18] | 0.52 | 1.93 | [0.25–15.13] | 0.54 |
| DRa | 9.61 | [3.05–30.23] | <0.001 | 9.96 | [2.39–41.50] | 0.01 | 1.45 | [0.50–4.24] | 0.51 |
| Any ocular disease | 5.54 | [1.83–16.74] | 0.01 | 5.52 | [1.79–16.99] | 0.01 | 5.18 | [1.46–18.42] | 0.03 |
Data was weighted estimates and expressed as OR [95% confidence interval].
MSVI moderate and severe visual impairment, DR diabetic retinopathy, AMD age-related macular degeneration, CI confidence interval, OR odds ratio.
aAmong participants with diabetes mellitus, model 2 additionally adjusted for HbA1c.
bAdjusted for age and gender.
cAdjusted for age, gender, race/ethnicity, education, marital status, and poverty income ratios.
dAdditionally adjusted for BMI, diastolic blood pressure, systolic blood pressure, diabetes, coronary heart disease, angina, hypertension and depression based on model 2.
Table 3 presented the analyses stratified by diabetic and hypertension status. After controlling multiple confounders, significant associations were also found between DR and any ocular diseased with stroke among diabetic participants in the adjusted model. In the analyses stratified by hypertension status, stroke was closely related to MSVI, and the absence of stroke was independently associated with cataract (all P < 0.05).
Table 3.
Association between visual impairment, major eye diseases, and stroke stratified by diabetes and hypertension status.
| Diabetes | Hypertension | |||
|---|---|---|---|---|
| Absent (n = 3988) | Present (n = 582)a | Absent (n = 3391) | Present (n = 1179) | |
| Visual impairment | ||||
| No | Ref | Ref | Ref | Ref |
| mild | 1.60 [1.23–2.07] | 0.81 [0.28–2.32] | 0.83 [0.53–1.29] | 0.02 [0.00–1.05] |
| MSVI | 1.69 [1.20–2.38] | 2.76 [1.05–7.25] | 0.66 [0.34–1.27] | 1.43 [0.12–16.90] |
| DR | 3.56 [1.39–9.11] | 4.52 [1.83–11.13] | 1.26 [0.57–2.80] | 1.58 [0.34–7.27] |
| AMD | 0.52 [0.28–0.96] | 2.90 [1.12–7.49] | 1.24 [0.48–3.19] | 3.20 [0.36–28.54] |
| Cataract | 1.48 [1.05–2.08] | 2.73 [1.06–7.06] | 1.97 [1.23–3.14] | 1.20 [0.29–4.87] |
| Glaucoma | 1.36 [0.96–1.91] | 2.18 [0.65–7.33] | 1.11 [0.61–2.03] | 3.30 [0.50–21.86] |
| Any ocular disease | 5.03 [3.51–7.19] | 11.03 [3.57–34.11] | 1.53 [0.93–2.52] | 10.68 [0.91–125.57] |
Data was weighted estimates and expressed as OR [95% confidence interval].
The models were all adjusted for age and gender.
MSVI moderate and serve visual impairment, DR diabetic retinopathy, AMD age-related macular degeneration, Ref reference.
Bold: P < 0.05.
aAmong participants with diabetes mellitus, the model additionally adjusted for HbA1c.
Discussion
In this US nationally representative sample of 4570 participants aged 40 years or older, we find that participants with stroke have significantly higher prevalence of VI and major eye diseases than those without. After the data were weighted, we found that 207 participants had stroke, representing 3.2 million US adults. After adjustments for demographic and clinical measurements confounders, the associations are limited to mild VI and any ocular disease. These findings do not downplay the important roles that stroke may play in the prevention of MSVI or other ocular diseases such as glaucoma or cataract. Rather, they show that the influence of stroke in the development of these diseases may be confounded by other factors such as age, race, or socioeconomic status.
Previous studies have demonstrated the association between stroke and different eye diseases. The Beijing Eye Study has found that among the stroke patients, the OR of diabetic retinopathy reaches 4.41 (95% CI: 2.38–8.18) [20]. Another nested case-control study has also found that the estimated relative risk of stroke in diabetic patients with retinopathy is 4.00 (95% CI: 1.00–14.50) after adjustment of systemic risk factors [21]. The Rotterdan Study has revealed that patients with late AMD are strongly associated with an increased risk of stroke (OR = 1.56, 95% CI: 1.08–2.26) [22]. Study has also found that patients with open-angle glaucoma have a 1.52-fold (95%CI: 1.40–1.72) higher risk of having stroke than the comparison cohort [23]. Our study, using a nationally representative and population-based sample, further verified the greater burden of VI and major eye diseases with stroke. Our study has greater generalizability to ethnically diverse population in the US compared to the previous studies. And it is relevant to an aging society highlighting the importance of identifying VI and major ocular diseases among stroke patients. Our results support an idea to make eye health a population health imperative, with vision screenings, epidemiology and population-based research. Public health infrastructure is needed to improve eye health awareness and accessibility to care.
In our study, we find that stroke is closely related to mild VI, DR, and any ocular diseases after adjustment for demographic variables, and it is closely related to mild VI, and any ocular disease independent of confounding factors. These results are confirmed in other studies, because age and gender are all powerful non-modifiable predictor of both stroke and major eye disease. The prevalence of stroke was similar between men and women younger than 55 years old, but significantly greater for men than women at ages 55–75 years old [2]. It has been found that about 16% of stroke survivors have visual problems and strokes with greater severity are likely to cause visual disturbance [22, 23]. Despite impaired central vision, which is the most common visual impairment in stroke patients, eye movement disorders, visual field loss and visual perceptual disorders are also usually found among stroke patients, and most patients have a combination of several visual problems. Impaired central vision in stroke survivors is often due to coexistent ocular problems [24]. Visual field loss occurs after visual pathway damage, while eye movement disorders occur due to direct damage to the cortical, nuclear or infranuclear pathways among stroke patients [24, 25]. With the aging of the population, screening for eye diseases is important for both stroke patients and the elderly. We support the need for vision screening in the older population, claiming strong and compelling reasons for screening owing to the impact of vision on life quality and the availability of treatments for many of the most common aetiologies of poor vision diseases including cataract, DR and AMD.
In our analyses stratified by diabetic status, stroke is associated with DR (OR = 4.52, 95% CI: 1.83–11.13) and any ocular disease (OR = 11.03, 95% CI: 3.57–34.11). The reason may be that patients with diabetes have a higher risk of developing stroke and ocular diseases than the general population, so that ocular diseases such as DR and AMD may be associated with macrovascular sequelae of stroke [26]. In the model stratified by hypertension status, stroke is an independent risk factor for MSVI (OR = 1.43, 95%CI: 0.12–16.90). While other studies show that hypertension has been an independent risk factor for DR, however it is not confirmed in all the work including ours [26, 27]. Previous studies have also suggested that hypertension is a relevant risk factor for development of AMD [28, 29], which is not significantly associated in our work. It will need more research and data to explore the relation between hypertension and ocular diseases.
In summary, we think that the incidence of visual problems of all stroke survivors should be taken seriously, because we have revealed the association between major eye disease and VI with stroke, and hypertension and diabetes are also associated with eye diseases among stroke patients. Early assessment leads to early intervention, which may have functional significance for patients and stroke teams. Since ocular diseases and stroke share some common pathogeneses, early retinal signs may indicate the occurrence of stroke so that regularly ocular examinations may lead early interventions of stroke. It is also generalized to the ophthalmology field that screening for eye diseases among old people is also important, even they did not suffer from stroke.
Our study is a population-based study on the data from the US CDC National Health and Nutrition Examination Survey (NHANES). It has a relatively large sample size, representing the general adults in the US. We build several models that are adjusted for a wide range of variables, including demographic and clinical measurements factors. However, there are several limitations in our study as well. First, we cannot draw a causal relationship due to the cross-sectional design of our study. Second, our study is subjected to a potential recall bias because the information of some ocular diseases and stroke were obtained by self-report questionnaire, and health service accessibility affects the incidence of ever reports of the diseases. Thirdly, a longitudinal study with group-based trajectory modelling is needed to explore the long-term association of stroke and ocular diseases. What’s more, NHANES doesn’t differentiate types of stroke, and it is possible that ischemic and haemorrhagic stroke have different biological interaction with ocular diseases. Lastly, data generated from NHANES 2005–2008 might not well represent contemporary association between stroke and ocular diseases.
Conclusion
Our cross-sectional study shows stroke is associated with increased prevalence of ocular diseases. These findings highlight the importance of ocular screening among stroke patients and potential common pathogeneses underlying these conditions.
Summary
What was known before
It has been found that about 16% of stroke survivors have visual problems, and strokes with greater severity are likely to cause visual disturbance.
Major eye diseases, including AMD, glaucoma and DR were all associated with stroke, and diabetes and hypertension may be relevant to ocular diseases among stroke patients.
What this study adds
This study has greater generalizability to ethnically diverse population in the US compared to the previous studies.
In this stroke participants cohort, significant associations were found between DR and any ocular disease among diabetic participants. Stroke was closely related to MSVI among hypertension participants.
Supplementary information
Author contributions
W.B. Wei, H.Y Li and Q. Yang designed the study, H.Y Li, L. Dong and Q. Yang wrote the manuscript. H.Y Li, W.D Zhou, H.T Wu, Y.F Li, and R. H Zhang collected the data and conducted the analyses, W.B. Wei edited and revised the manuscript. All authors have approved the submitted version and agreed with the contributions declarations.
Funding
This study was supported by National Natural Science Foundation of China (82141128); The Capital Health Research and Development of Special (2020–1–2052); Science & Technology Project of Beijing Municipal Science & Technology Commission (Z201100005520045, Z181100001818003).
Data availability
Data supporting the findings of this study are available from https://www.cdc.gov/nchs/nhanes/index.htm.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
These authors contributed equally: He-Yan Li, Qiong Yang.
Supplementary information
The online version contains supplementary material available at 10.1038/s41433-022-02238-5.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
Data supporting the findings of this study are available from https://www.cdc.gov/nchs/nhanes/index.htm.