Association of Dietary and Supplementary Calcium Intake With Age-Related Macular Degeneration: Age-Related Eye Disease Study Report 39

The impact of 25-hydroxyvitamin D and calcium on risk of age-related macular degeneration: a Mendelian randomization study

BACKGROUND

The relationships between 25-hydroxyvitamin D [25(OH)D] and calcium and age-related macular degeneration (AMD) are unclear.

OBJECTIVES

This study aimed to investigate the causal role of 25(OH)D concentrations, calcium concentrations, and dietary supplements use of vitamin D and calcium on risk of AMD and its subtypes.

METHODS

Independent genetic variants associated with 25(OH)D and calcium concentrations were used as instrumental variables in published genome-wide association studies (GWASs) of European ancestry. The bidirectional 2-sample Mendelian randomization (MR) analyses were performed using summary-level data from the UK Biobank and FinnGen datasets. Sensitivity analyses were conducted to ensure the robustness of the MR results. The meta-analyses were conducted using both fixed-effect and random-effect models to provide comprehensive and reliable estimates.

RESULTS

A standard deviation increase in calcium concentrations was linked to a 14%, 17%, and 13% reduction in the likelihood of developing AMD (95% confidence interval [CI]: 0.77, 0.97), wet AMD (95% CI: 0.73, 0.95), and dry AMD (95% CI: 0.75, 1.00), respectively. No significant causal relationships were detected between genetically predicted 25(OH)D concentrations and AMD and its subtypes (all P > 0.05). The combined analyses showed that higher calcium concentrations were associated with a reduced risk of overall AMD, with an odds ratio of 0.89 (95% CI: 0.81, 0.98).

CONCLUSIONS

This study provides evidence supporting the causal relationship between calcium concentrations and risk of AMD and its subtypes, which may have important implications for the prevention, monitoring, and treatment of AMD.

Natural products for the treatment of age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a chronic retinal disease that significantly influences the vision of the elderly.

PURPOSE

There is no effective treatment and prevention method. The pathogenic process behind AMD is complex, including oxidative stress, inflammation, and neovascularization. It has been demonstrated that several natural products can be used to manage AMD, but systematic summaries are lacking.

STUDY DESIGN AND METHODS

PubMed, Web of Science, and ClinicalTrials.gov were searched using the keywords "Biological Products" AND "Macular Degeneration" for studies published within the last decade until May 2023 to summarize the latest findings on the prevention and treatment of age-related macular degeneration through the herbal medicines and functional foods.

RESULTS

The eligible studies were screened, and the relevant information about the therapeutic action and mechanism of natural products used to treat AMD was extracted. Our findings demonstrate that natural substances, including retinol, phenols, and other natural products, prevent the development of new blood vessels and protect the retina from oxidative stress in cells and animal models. However, they have barely been examined in clinical studies.

CONCLUSION

Natural products could be highly prospective candidate drugs used to treat AMD, and further preclinical and clinical research is required to validate it to control the disease.

Effect of statins on the age of onset of age-related macular degeneration

BACKGROUND

This study evaluated the relationship between statin use and the age of onset of age-related macular degeneration (AMD).

METHODS

Electronic Health Records from 52,840 patients evaluated at University of California Los Angeles (UCLA) Ophthalmology Clinics and 9,977 patients evaluated at University of California San Francisco (UCSF) Ophthalmology Clinics were screened. Survival analysis was performed using Cox proportional hazards regression models and visualized using Kaplan Meier survival curves, with the following covariates-sex, ethnicity, smoking history, fluoxetine use, obesity, diabetes mellitus, and hypertension.

RESULTS

5,498 of 52,840 patients at UCLA were diagnosed with AMD. Statin use was associated with a later AMD onset (HR = 0.8823, p < 0.0001), while female sex (HR = 1.0852, p= 00,035), obesity (HR = 1.4555, p < 0.0001), and fluoxetine (HR = 1.3797, p= 0.0003) were associated with an earlier AMD onset. Non-hispanic black (HR = 0.5687, p < 0.0001) and hispanic ethnicities (HR = 0.8269, p= 0.0028) were associated with a later AMD onset. When stratifying for ethnicity, statins, fluoxetine, sex, and obesity were significant only within non-hispanic white subjects. Statin use was significant among patients with dry AMD (HR = 0.8410, p= 0.0001) but not wet AMD (0.9188, p= 0.0351). In the replication cohort, 526 of 9,977 patients at UCSF had AMD. Associations between statins (HR = 0.7643, p= 0.0033), non-hispanic black ethnicity (HR = 0.5043, p= 0.0035), and obesity (HR = 1.9602, p < 0.0001) on AMD onset were confirmed.

CONCLUSIONS

In both cohorts, statin use and non-hispanic black ethnicity are associated with a later AMD onset, while obesity with an earlier AMD onset.

The Relationship between Dietary Calcium and Age-Related Macular Degeneration

BACKGROUND

Mineral element supplements are widely used in the older adult population. However, little is known of their impact on the progression of age-related macular degeneration (ARMD). The aim of this study was to examine the association between dietary micronutrients and ARMD in older adults.

METHODS

We enrolled 5227 participants from the National Health and Nutrition Examination Survey (NHANES 2005-2008) in this cross-sectional study. ARMD was evaluated using an ophthalmic digital imaging system and digital camera. Mineral element consumption was collected using a 24-hour dietary recall. The association between mineral element use and the presence of ARMD was determined by multivariable logistic regression.

RESULTS

After adjusting for relevant variables, dietary calcium was negatively associated with ARMD (OR: 680, 95%CI: 0.482-0.960). In contrast to dietary form, serum concentration of calcium was not associated with ARMD. Moreover, increased dietary calcium was associated with reduced ARMD (OR: 0.684, 95%CI: 0.468-1.000).

CONCLUSION

A lower consumption of dietary calcium was significantly associated with a higher risk of ARMD. Further longitudinal studies are necessary to explore these findings.

What did we learn in 35 years of research on nutrition and supplements for age-related macular degeneration: a systematic review

The aim of this paper is to summarize all available evidence from systematic reviews, randomized controlled trials (RCTs) and comparative nonrandomized studies (NRS) on the association between nutrition and antioxidant, vitamin, and mineral supplements and the development or progression of age-related macular degeneration (AMD). The Cochrane Database of Systematic Reviews, Cochrane register CENTRAL, MEDLINE and Embase were searched and studies published between January 2015 and May 2021 were included. The certainty of evidence was assessed according to the GRADE methodology. The main outcome measures were development of AMD, progression of AMD, and side effects. We included 7 systematic reviews, 7 RCTs, and 13 NRS. A high consumption of specific nutrients, i.e. β-carotene, lutein and zeaxanthin, copper, folate, magnesium, vitamin A, niacin, vitamin B6, vitamin C, docosahexaenoic acid, and eicosapentaenoic acid, was associated with a lower risk of progression of early to late AMD (high certainty of evidence). Use of antioxidant supplements and adherence to a Mediterranean diet, characterized by a high consumption of vegetables, whole grains, and nuts and a low consumption of red meat, were associated with a decreased risk of progression of early to late AMD (moderate certainty of evidence). A high consumption of alcohol was associated with a higher risk of developing AMD (moderate certainty of evidence). Supplementary vitamin C, vitamin E, or β-carotene were not associated with the development of AMD, and supplementary omega-3 fatty acids were not associated with progression to late AMD (high certainty of evidence). Research in the last 35 years included in our overview supports that a high intake of specific nutrients, the use of antioxidant supplements and adherence to a Mediterranean diet decrease the risk of progression of early to late AMD.

Reduced serum calcium is associated with a higher risk of retinopathy in non-diabetic individuals: The Chinese Multi-provincial Cohort Study

AIMS

As a common micro-vascular disease, retinopathy can also present in non-diabetic individuals and increase the risk of clinical cardiovascular disease. Understanding the relationship between serum calcium and retinopathy would contribute to etiological study and disease prevention.

METHODS

A total of 1836 participants (aged 55-84 years and diabetes-free) from the Chinese Multi-Provincial Cohort Study-Beijing Project in 2012 were included for analyzing the relation between serum calcium level and retinopathy prevalence. Of these, 1407 non-diabetic participants with data on serum calcium in both the 2007 and 2012 surveys were included for analyzing the association of five-year changes in serum calcium with retinopathy risk. The retinopathy was determined from retinal images by ophthalmologists and a computer-aided system using convolutional neural network (CNN). The association between serum calcium and retinopathy risk was assessed by multivariate logistic regression.

RESULTS

Among the 1836 participants (male, 42.5%), 330 (18.0%) had retinopathy determined by CNN. After multivariate adjustment, the odds ratio (OR) comparing the lowest quartiles (serum calcium < 2.38 mmol/L) to the highest quartiles (serum calcium ≥ 2.50 mmol/L) for the prevalence of retinopathy determined by CNN was 1.58 (95% confidence interval [CI]: 1.10 - 2.27). The findings were consistent with the result discerned by ophthalmologists, and either by CNN or ophthalmologists. These relationships are preserved even in those without metabolic risk factors, including hypertension, high hemoglobin A1c, high fasting blood glucose, or high low-density lipoprotein cholesterol. Over 5 years, participants with the sustainably low levels of serum calcium (OR: 1.58; 95%CI: 1.05 - 2.39) and those who experienced a decrease in serum calcium (OR: 1.56; 95%CI: 1.04 - 2.35) had an increased risk of retinopathy than those with the sustainably high level of serum calcium.

CONCLUSIONS

Reduced serum calcium was independently associated with an increased risk of retinopathy in non-diabetic individuals. Moreover, reduction of serum calcium could further increase the risk of retinopathy even in the absence of hypertension, high glucose, or high cholesterol. This study suggested that maintaining a high level of serum calcium may be recommended for reducing the growing burden of retinopathy. Further large prospective studies will allow more detailed information.

Peripheral Monocyte Count and Age-Related Macular Degeneration. The Tongren Health Care Study

PURPOSE

To assess potential associations between the prevalence of age-related macular degeneration (AMD) and systemic parameters in a Chinese population.

DESIGN

Cross-sectional study.

METHODS

The Tongren Health Care Study included individuals attending regular health care check-up examinations in the Beijing Tongren Hospital from 2017 to 2019. Detailed medical examinations and ophthalmic examinations were applied, including fundus photography. AMD was evaluated according to the Beckman Initiative guidelines.

RESULTS

The study included 7,719 participants (mean age: 60.5 ± 8.1 years; range: 50-97 years). The prevalence of any, early, intermediate, and late AMD was 1,607 of 7,719 (20.8%; 95% confidence interval [CI]: 20.1%, 21.9%), 832 of 7,719 (10.8%; 95% CI: 10.1%, 11.5%), 733 of 7,719 (9.5%; 95% CI: 8.9%, 10.2%), and 42 of 7,719 (0.50%; 95% CI: 0.40%, 0.70%), respectively. In multivariate analysis, the prevalence of any AMD increased with higher blood monocyte count (odds ratio [OR]:3.49; 95% CI: 2.26, 5.38; P < .001), after adjusting for older age (OR: 1.06; 95% CI: 1.05, 1.07; P < .001), higher serum concentration of calcium (OR: 2.52; 95% CI: 1.32, 4.84; P = .005), high-density lipoproteins (OR: 1.39; 95% CI: 1.19, 1.61; P < .001), and lower lipoprotein a (OR: 0.99; 95% CI: 0.98, 0.99; P = .02). Similar findings were obtained for the prevalence of intermediate and late AMD combined. The association between higher monocyte count and higher AMD prevalence showed the highest odds ratio for the age group of 50-59 years (any AMD: OR: 4.35, P < .001; intermediate and late AMD: OR: 6.14, P < .001). Individuals with a monocyte count of ≥0.5 × 10⁹/L as compared to participants with a monocyte of 0.1-0.4 × 10⁹/L had a 1.45-fold increased risk for any AMD (OR: 1.45; 95% CI: 1.27, 1.64; P < .001) and 1.58 fold increase risk for intermediate/late AMD (OR: 1.58; 95% CI: 1.33, 1.87; P < .001).

CONCLUSION

A higher prevalence of early AMD, intermediate AMD, late AMD, and any AMD was associated with a higher peripheral monocyte count. In agreement with previous studies, the observation suggests monocytes playing a role in the pathogenesis of AMD.

Age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of legal blindness in the industrialized world. AMD is characterized by accumulation of extracellular deposits, namely drusen, along with progressive degeneration of photoreceptors and adjacent tissues. AMD is a multifactorial disease encompassing a complex interplay between ageing, environmental risk factors and genetic susceptibility. Chronic inflammation, lipid deposition, oxidative stress and impaired extracellular matrix maintenance are strongly implicated in AMD pathogenesis. However, the exact interactions of pathophysiological events that culminate in drusen formation and the associated degeneration processes remain to be elucidated. Despite tremendous advances in clinical care and in unravelling pathophysiological mechanisms, the unmet medical need related to AMD remains substantial. Although there have been major breakthroughs in the treatment of exudative AMD, no efficacious treatment is yet available to prevent progressive irreversible photoreceptor degeneration, which leads to central vision loss. Compelling progress in high-resolution retinal imaging has enabled refined phenotyping of AMD in vivo. These insights, in combination with clinicopathological and genetic correlations, have underscored the heterogeneity of AMD. Hence, our current understanding promotes the view that AMD represents a disease spectrum comprising distinct phenotypes with different mechanisms of pathogenesis. Hence, tailoring therapeutics to specific phenotypes and stages may, in the future, be the key to preventing irreversible vision loss.

[Nutritional advices for postmenopausal woman. Postmenopausal women management: CNGOF and GEMVi clinical practice guidelines]

Menopause is a key period for health due to physiological changes, particularly of body composition (with decrease of lean mass and increase of fat mass) and of body fat distribution, leading to a higher risk for bone and muscular health and cardiometabolic health. Nutritional advices, associated to physical activity advices, may partially prevent these effects. The energy balance will be moderately negative if there is a weight gain, while the protein intake will be preserved and a regular physical activity will be increased. A Mediterranean style diet will be beneficial on cardiovascular health. Dairy products will be preserved, but restrictive and dietary exclusion will be avoided.

Sodium-Sensitive Contact Lens for Diagnostics of Ocular Pathologies

The ability to measure all the electrolyte concentrations in tears would be valuable in ophthalmology for research and diagnosis of dry eye disease (DED) and other ocular pathologies. However, tear samples are difficult to collect and analyze because the total volume is small and the chemical composition changes rapidly. Measurements of electrolytes in tears is challenging because typical clinical assays for proteins and other biomarkers cannot be used to detect ion concentrations tears. Here, we report the contact lens which is sensitive to sodium ion (Na+), one of the dominant electrolytes in tears. The Na ions in tears is diagnostic for DED. Three sodium-sensitive fluorophores (SG-C16, SG-LPE and SG-PL) were synthesized by derivatizing the sodium green with 1-hexadecyl amine, 1-oleoyl-2-hydroxy-sn-glycero-3-phosphoethanolamine or poly-L-lysine, respectively. These probes were bound to modern silicone hydrogel (SiHG) contact lens, Biofinity from Cooper Vision. Doped lenses were tested for sodium ion dependent spectral properties of probes within the contact lens. The probes displayed changes in intensity and lifetime in response to Na+ concentration, were completely reversible, no significant probe wash-out from the lenses, were not affected by proteins in tears and were not removed after repeated washing. These results are the first step to our long-term goal, which is a lens sensitive to all the electrolytes in tears. We presented design, synthesis and implementation of three new sodium sensitive probes within a silicon hydrogel lens. Contact lenses to measure the other electrolytes in tears can be developed using the same approach by synthesis and testing of new ion-sensitive fluorophores.

Adequacy of calcium intake in Spanish population according age groups

This review shows the estimated calcium intake in Spain in recent years. Our results indicate that adolescents and the elderly are at risk of insufficient calcium intake. By using the national and the European recommendations, this work contributes to map and compare population's dietary calcium intake in the European countries. PURPOSE AND METHODS : The present work aims to examine calcium intake in the healthy Spanish population of any age and analyze its adequacy to the calcium Recommended Dietary Intake (RDI) for different groups in Spanish population, as well to the Adequate Intake (AI) or Population Reference Intake (PRI) estimated by European Food Safety Authority (EFSA). Forty-three studies published in the last 5 years were eligible for review. RESULTS AND CONCLUSIONS: The results show that infants and children exceed Spanish and EFSA dietary recommendations, adults meet more that 80% of the RDI and EFSA recommendations, and the estimated average calcium intake in the adolescent and elderly groups does not reach 75% of the recommended intake. Representative national studies with a common methodology to estimate calcium intake are needed.

Differential Expression of Kinin Receptors in Human Wet and Dry Age-Related Macular Degeneration Retinae

Kinins are vasoactive peptides and mediators of inflammation, which signal through two G protein-coupled receptors, B1 and B2 receptors (B1R, B2R). Recent pre-clinical findings suggest a primary role for B1R in a rat model of wet age-related macular degeneration (AMD). The aim of the present study was to investigate whether kinin receptors are differentially expressed in human wet and dry AMD retinae. The cellular distribution of B1R and B2R was examined by immunofluorescence and in situ hybridization in post-mortem human AMD retinae. The association of B1R with inflammatory proteins (inducible nitric oxide synthase (iNOS) and vascular endothelial growth factor A (VEGFA)), fibrosis markers and glial cells was also studied. While B2R mRNA and protein expression was not affected by AMD, a significant increase of B1R mRNA and immunoreactivity was measured in wet AMD retinae when compared to control and dry AMD retinae. B1R was expressed by Müller cells, astrocytes, microglia and endothelial/vascular smooth muscle cells, and colocalized with iNOS and fibrosis markers, but not with VEGFA. In conclusion, the induction and upregulation of the pro-inflammatory and pro-fibrotic kinin B1R in human wet AMD retinae support previous pre-clinical studies and provide a clinical proof-of-concept that B1R represents an attractive therapeutic target worth exploring in this retinal disease.