Gender and cataract--the role of estrogen

Incidence and Determinants of Intraocular Lens Implantation in Type 2 Diabetes: The Fremantle Diabetes Study Phase II

OBJECTIVE

To compare the incidence of intraocular lens (IOL) implantation for cataracts between people with and without type 2 diabetes and to determine associated risk factors in those with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Participants with type 2 diabetes (n = 1,499) from the community-based observational Fremantle Diabetes Study Phase II (FDS2) were age, sex, and zip code matched 1:4 with residents without diabetes. IOL implantation status was ascertained between entry (2008-2011) and the end of 2016 using validated data linkage. Age-specific incidence rates and incidence rate ratios (IRRs) for cataract surgery were calculated. Predictors of IOL implantation in FDS2 participants were assessed using proportional hazards and competing risk regression modeling.

RESULTS

The crude IRR (95% CI) for cataract surgery in FDS2 participants (mean ± SD age 62.8 ± 10.8 years at entry) versus the matched group without diabetes was 1.50 (1.32-1.71), with the highest relative risk in those aged 45-54 years at the time of surgery (7.12 [2.05-27.66]). Competing risk analysis showed that age at entry, diabetes duration, serum HDL cholesterol, serum triglycerides, a severe hypoglycemic episode in the past year, and Asian and southern European ethnicity increased the risk of cataract surgery in participants with type 2 diabetes (P ≤ 0.025).

CONCLUSIONS

People with type 2 diabetes, especially those in younger age-groups, are at a significantly increased risk of cataract surgery than matched people without diabetes. Multifaceted prevention strategies should be incorporated as part of routine care. As well as limiting ultraviolet light exposure, these might include lipid-modifying treatment and strategies to avoid severe hypoglycemia.

Distribution gaps in cataract surgery care and impact on seniors across Ontario

OBJECTIVE

To assess recent cataract service delivery across communities of all sizes in Ontario.

DESIGN

Retrospective analysis of health records.

PARTICIPANTS

All Ontario Health Insurance Plan users.

METHODS

Raw physician Ontario Health Insurance Plan claims data for cataract surgery (E140A, E214A) from April 1, 2009, to March 31, 2014, were extracted from the Ontario Ministry of Health and Long-Term Care (MOHLTC) IntelliHealth database. Cataract surgery claims data were sorted by sex, by age, and by Ontario's 444 municipalities based on patient residence. Cataract surgery distribution was examined by population centre: Large Urban (≥100 000 persons), Medium (30 000-99 999 persons), Small (1000-29 999 persons), and Rural (<1000 persons) as defined by Statistics Canada. Wait times were extracted from the MOHLTC wait times database. Cataract surgery rate (CSR), defined as the number of cataract surgeries performed per million, was calculated.

RESULTS

Cataract surgery volumes remained unchanged from 2010 to 2014. Mean patient age was 71.6 ± 10 years. Patients lived in large urban (63%), medium (15%), small (21%), and rural (0.6%) communities. Mean wait times increased by 28% to 68.5 days, and 90th percentile wait times increased by 44% to 154.3 days. A reduction in CSR was observed among seniors aged 65-74 years (-10%) and 75+ years (-16%). Rural communities showed the largest decline (-19%). Among seniors aged ≥75 years, CSR declined the most for those living in rural communities (-25%).

CONCLUSIONS

Adjusting the current government policy of zero-growth in cataract surgery volumes will support growing demands for cataract care in our aging population.

The national and subnational prevalence of cataract and cataract blindness in China: a systematic review and meta-analysis

Background

Cataract is the second leading cause of visual impairment and the first of blindness globally. However, for the most populous country, China, much remains to be understood about the scale of cataract and cataract blindness. We aimed to investigate the prevalence of cataract and cataract blindness in China at both the national and subnational levels, with projections till 2050.

Methods

In this systematic review and meta-analysis, China National Knowledge Infrastructure (CNKI), Wanfang, Chinese Biomedicine Literature Database (CBM-SinoMed), PubMed, Embase, and Medline were searched using a comprehensive search strategy to identify all relevant articles on the prevalence of cataract or cataract blindness in Chinese population published from January 1990 onwards. We fitted a multilevel mixed-effects meta-regression model to estimate the prevalence of cataract, and a random-effects meta-analysis model to pool the overall prevalence of cataract blindness. The United Nations Population Division (UNPD) data were used to estimate and project the number of people with cataract and cataract blindness from 1990 to 2050. According to different demographic and geographic features in the six geographic regions in China, the national numbers of people with cataract in the years 2000 and 2010 were distributed to each region.

Results

In males, the prevalence of any cataract (including post-surgical cases) ranged from 6.71% (95% CI = 5.06-8.83) in people aged 45-49 years to 73.01% (95% CI = 65.78-79.2) in elderly aged 85-89 years. In females, the prevalence of any cataract increased from 8.39% (95% CI = 6.36-10.98) in individuals aged 45-49 years to 77.51% (95% CI = 71.00-82.90) in those aged 85-89 years. For age-related cataract (ARC, including post-surgical cases), in males, the prevalence rates ranged from 3.23% (95% CI = 1.51-6.80) in adults aged 45-49 years to 65.78% (95% CI = 46.72-80.82) in those aged 85-89 years. The prevalence of ARC in females was 4.72% (95% CI = 2.22-9.76) in the 45-49 years age group and 74.03% (95% CI = 56.53-86.21) in the 85–89 years age group. The pooled prevalence rate of cataract blindness (including post-surgical cases) by best corrected visual acuity (BCVA)<0.05 among middle-aged and older Chinese was 2.30% (95% CI = 1.72-3.07), and those of cataract blindness by BCVA<0.10 and cataract blindness by presenting visual acuity (PVA)<0.10 were 2.56% (95% CI = 1.94-3.38) and 4.51% (95% CI = 3.53-5.75) respectively. In people aged 45-89 years, the number of any cataract cases was 50.75 million (95% CI = 42.17-60.37) in 1990 and 111.74 million (95% CI = 92.94-132.84) in 2015, and that of ARC rose from 35.77 million (95% CI = 19.81-59.55) in 1990 to 79.04 million (95% CI = 44.14-130.85) in 2015. By 2050, it is projected that the number of people (45-89 years of age) affected by any cataract will be 240.83 million (95% CI = 206.07-277.35), and that of those with ARC will be 187.26 million (95% CI = 113.17-281.23). During 2000 and 2010, South Central China consistently owed the most cases of any cataract, whereas Northwest China the least.

Conclusions

The prevalence of cataract and cataract blindness in China was unmasked. In the coming decades, cataract and cataract blindness will continue to be a leading public-health issue in China due to the ageing population. Future work should be prioritized to the promotion of high-quality epidemiological studies on cataract.

The national and subnational prevalence of cataract and cataract blindness in China: a systematic review and meta-analysis

Background

Cataract is the second leading cause of visual impairment and the first of blindness globally. However, for the most populous country, China, much remains to be understood about the scale of cataract and cataract blindness. We aimed to investigate the prevalence of cataract and cataract blindness in China at both the national and subnational levels, with projections till 2050.

Methods

In this systematic review and meta-analysis, China National Knowledge Infrastructure (CNKI), Wanfang, Chinese Biomedicine Literature Database (CBM-SinoMed), PubMed, Embase, and Medline were searched using a comprehensive search strategy to identify all relevant articles on the prevalence of cataract or cataract blindness in Chinese population published from January 1990 onwards. We fitted a multilevel mixed-effects meta-regression model to estimate the prevalence of cataract, and a random-effects meta-analysis model to pool the overall prevalence of cataract blindness. The United Nations Population Division (UNPD) data were used to estimate and project the number of people with cataract and cataract blindness from 1990 to 2050. According to different demographic and geographic features in the six geographic regions in China, the national numbers of people with cataract in the years 2000 and 2010 were distributed to each region.

Results

In males, the prevalence of any cataract (including post-surgical cases) ranged from 6.71% (95% CI = 5.06-8.83) in people aged 45-49 years to 73.01% (95% CI = 65.78-79.2) in elderly aged 85-89 years. In females, the prevalence of any cataract increased from 8.39% (95% CI = 6.36-10.98) in individuals aged 45-49 years to 77.51% (95% CI = 71.00-82.90) in those aged 85-89 years. For age-related cataract (ARC, including post-surgical cases), in males, the prevalence rates ranged from 3.23% (95% CI = 1.51-6.80) in adults aged 45-49 years to 65.78% (95% CI = 46.72-80.82) in those aged 85-89 years. The prevalence of ARC in females was 4.72% (95% CI = 2.22-9.76) in the 45-49 years age group and 74.03% (95% CI = 56.53-86.21) in the 85-89 years age group. The pooled prevalence rate of cataract blindness (including post-surgical cases) by best corrected visual acuity (BCVA)<0.05 among middle-aged and older Chinese was 2.30% (95% CI = 1.72-3.07), and those of cataract blindness by BCVA<0.10 and cataract blindness by presenting visual acuity (PVA)<0.10 were 2.56% (95% CI = 1.94-3.38) and 4.51% (95% CI = 3.53-5.75) respectively. In people aged 45-89 years, the number of any cataract cases was 50.75 million (95% CI = 42.17-60.37) in 1990 and 111.74 million (95% CI = 92.94-132.84) in 2015, and that of ARC rose from 35.77 million (95% CI = 19.81-59.55) in 1990 to 79.04 million (95% CI = 44.14-130.85) in 2015. By 2050, it is projected that the number of people (45-89 years of age) affected by any cataract will be 240.83 million (95% CI = 206.07-277.35), and that of those with ARC will be 187.26 million (95% CI = 113.17-281.23). During 2000 and 2010, South Central China consistently owed the most cases of any cataract, whereas Northwest China the least.

Conclusions

The prevalence of cataract and cataract blindness in China was unmasked. In the coming decades, cataract and cataract blindness will continue to be a leading public-health issue in China due to the ageing population. Future work should be prioritized to the promotion of high-quality epidemiological studies on cataract.

Assessment of Horizontal Inequity in Eye Care Utilization in the Iranian Middle-aged Population

PURPOSE

The present study was designed to determine the extent that horizontal inequity was realized regarding eye care utilization in a middle-aged population as well as factors affecting this equity.

METHODS

Data were obtained from a population-based study (Shahroud Eye Cohort Study) in 2009 that included 5190 participants from 40 to 64 years of age. Horizontal inequity was determined based on the following variables: (i) economic status, (ii) eye care service needs, (iii) non-need variables, and (iv) eye care utilization (visiting an ophthalmologist or optometrist). Decomposition analysis of the concentration index based on a nonlinear model and indirect standardization was used to ascertain the contribution of each factor in inequity of eye care utilization.

RESULTS

After adjusting for need variables, the results of our study demonstrated that horizontal inequity in eye care utilization in a middle-aged Iranian population remained positive and significant (horizontal inequity: 0.19; 95% confidence interval: 0.17-0.23) indicating that use of services was focused among participants with a better financial situation. Furthermore, decomposition analysis demonstrated that educational level and economic status had the greatest contribution (54.1% and 41.1%, respectively) in comparison to other variables.

CONCLUSION

This study demonstrated that horizontal inequity exists in eye care utilization among the middle-aged Iranian population.

The clinical features of radiation cataract in patients with ocular adnexal mucosa-associated lymphoid tissue lymphoma

BACKGROUND

To examine the clinical features of radiation cataract in patients with ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphoma.

METHODS

Twenty-one patients with 26 eyes diagnosed with ocular adnexal MALT lymphoma (26 eyes), who were treated in Hokkaido University Hospital, were retrospectively reviewed based on medical records.

RESULTS

Out of the 21 patients, 16 patients (21 eyes) received radiation therapy (RT) with a total dose of 30 Gy. All cases eventually achieved complete remission. Eight of these patients (11 eyes: 52.3%) required cataract surgery after RT. The mean age at surgery was 56.8 (40-70) years. The mean latency between RT and the indication for surgery was 43.3 months. The percentage of females was significantly higher in patients who required surgery (P < 0.01), compared with those without surgery. The eyes of patients who received bolus technique on radiation treatment developed cataract more frequently (P < 0.05). In contrast, none of the patients without RT required cataract surgery.

CONCLUSIONS

Patients with ocular adnexal MALT lymphoma who underwent surgery for radiation cataract were seen more often in relatively young, female patients, and surgery was required about 3 years after RT. A long-term observation may be needed for patients after RT for a tumor. A female sex and the bolus technique may be risk factors for radiation cataract.

Effect of sex steroid hormone fluctuations in the pathophysiology of male-retinal pigment epithelial cells

Gender-based differences may influence the occurrence of several ocular conditions suggesting the possibility that fluctuations in sex steroid homeostasis may have direct effects on the eye physiology. Here, we evaluated the effect of sex steroid hormone fluctuations in male retinal pigment epithelial cells, RPEs (ARPE-19). To mimic hormonal fluctuations occurring during aging, we exposed ARPE-19 to acute, prolonged or chronic estradiol, and progesterone challenges. We found that chronic estradiol treatment promotes a remarkable necrosis of RPE cells, and does not affect pRb2/p130 or PAI-2 sub-cellular localization. In contrast, chronic progesterone exposure induces nuclear subcellular rearrangement of pRb2/p130, co-immunolocalization of pRb2/p130 with PAI-2, and accumulation of cells in G2/M phase, which is accompanied by a remarkable reduction of necrosis in favour of apoptosis activation. This study has a high clinical significance since it considers sex steroid fluctuations as inducers of milieu change in the retina able to influence pathological situations occurring with aging in non-reproductive systems such as the eye. Exogenous administration of physiologically significant amounts of sex hormones for long periods of time is a common clinical practice for transgender patients seeking sex reassignment. In particular, our study offers the unique opportunity to unravel the effects of sex hormones, not only in determining gender differences but also in affecting the physiology of non-reproductive systems, such as the eye, in the underserved transgender community.

Gonadal Hormones and Retinal Disorders: A Review

AIM

Gonadal hormones are essential for reproductive function, but can act on neural and other organ systems, and are probably the cause of the large majority of known sex differences in function and disease. The aim of this review is to provide evidence for this hypothesis in relation to eye disorders and to retinopathies in particular.

METHODS

Epidemiological studies and research articles were reviewed.

RESULTS

Analysis of the biological basis for a relationship between eye diseases and hormones showed that estrogen, androgen, and progesterone receptors are present throughout the eye and that these steroids are locally produced in ocular tissues. Sex hormones can have a neuroprotective action on the retina and modulate ocular blood flow. There are differences between the male and the female retina; moreover, sex hormones can influence the development (or not) of certain disorders. For example, exposure to endogenous estrogens, depending on age at menarche and menopause and number of pregnancies, and exposure to exogenous estrogens, as in hormone replacement therapy and use of oral contraceptives, appear to protect against age-related macular degeneration (both drusenoid and neurovascular types), whereas exogenous testosterone therapy is a risk factor for central serous chorioretinopathy. Macular hole is more common among women than men, particularly in postmenopausal women probably owing to the sudden drop in estrogen production in later middle age. Progestin therapy appears to ameliorate the course of retinitis pigmentosa. Diabetic retinopathy, a complication of diabetes, may be more common among men than women.

CONCLUSION

We observed a correlation between many retinopathies and sex, probably as a result of the protective effect some gonadal hormones may exert against the development of certain disorders. This may have ramifications for the use of hormone therapy in the treatment of eye disease and of retinal disorders in particular.

Assessing the influence of age and gender on the phenotype of myotonic dystrophy type 2

This study aims to provide a detailed clinical characterization of a large cohort of myotonic dystrophy type 2 (DM2) patients investigating the influence of age and gender as modifying factors of DM2 phenotype. A retrospective study was conducted on 307 patients with genetically confirmed DM2. The following data were analyzed: (1) demographics, (2) clinical features (first symptom, muscular complaints, and multisystemic involvement), (3) diagnostics (serological tests, electromyography, and muscle biopsy). In this cohort (186 females, 121 males), a proximal weakness was the leading symptom at onset (55.4%), followed by myalgia (35.5%) and myotonia (25.4%). Proximal weakness was more common in women than men (64.9 vs. 43.8%, p = 0.0006), whereas being male was associated with higher odds for developing myalgia [OR 2.94 (95% CI 1.53-5.67)]. Patients with muscle weakness at onset were older than those with myalgia and myotonia (p < 0.0001), while each additional disease year was associated with 10% decrease in the odds of developing myotonia [OR 0.9 (95% CI 0.87-0.93)] and 6% decrease of myalgia [OR 0.94 (95% CI 0.91-0.97)]. Cataract and thyroid diseases occurred more frequently in women (p = 0.002 and p = 0.002, respectively). Early onset of DM2 is an independent risk factor for the occurrence of multisystemic involvement [OR 0.94 (95% CI 0.90-0.98)]. In this updated clinical description of DM2 emerges a profound gender and age influence on the phenotype, emphasizing that female gender and ageing may be associated with a higher disease burden. These age- and gender-specific differences should be considered in diagnostics, management, and future clinical studies of DM2.

Timing of first childbirth and age-related cataract

OBJECTIVE

No studies investigated the effects of age at first childbirth on cataract formation. This study was performed to determine the relationships of age at first childbirth to age-related cataract in postmenopausal women.

METHODS

Study population included 7,021 postmenopausal women in the Korea National Health and Nutrition Examination Survey, 2008 to 2012. Participants were subdivided in quartiles according to the age at first childbirth as follows: 13 to 21, 22 to 23, 24 to 25, and 26 to 44 years. We used odds ratios (ORs) and 95% confidence intervals (CIs) to address the relationships between age at first childbirth and age-related cataract with adjustments for confounders.

RESULTS

Mean participants' age and age at first childbirth were 64.4 and 23.6 years, respectively. The prevalence of any subtype of age-related cataract was 64.9%. Nuclear cataract prevalence was significantly higher in postmenopausal women with later age at first childbirth (24-25 and 26-44 years) compared with those with the earliest age at first childbirth (13-21 years): ORs (95% CIs) were 1.23 (1.05-1.45) and 1.24 (1.05-1.46), respectively. A significant linear trend across quintile was observed (P = 0.006). Age at first childbirth linearly 4% (OR 1.04, 95% CI 1.01-1.06) and 2% (OR 1.02, 95% CI 1.00-1.04) increased risk for nuclear and cortical cataract formation, respectively. The population-attributable fraction of nuclear cataract caused by the first childbirth at 24 years or later was 4.9% (95% CI 1.20%-8.59%, P = 0.009).

CONCLUSIONS

Later age of first childbirth was independently associated with higher risks of nuclear and cortical cataract in postmenopausal women. Further prospective studies are needed to elucidate the role of age at first childbirth in developing age-related cataract.

Nuclear and Mitochondrial DNA of Age-Related Cataract Patients Are Susceptible to Oxidative Damage

PURPOSE

Reactive oxygen species caused by oxidative stress are considered as an important risk factor in the pathogenesis of age-related cataract (ARC). In addition, it has been shown that DNA damage has a potential role in the pathogenesis of cataract. In this study, background DNA damage, oxidative stress-induced DNA damage, and repair of nuclear and mitochondrial DNA of peripheral blood mononuclear cells (PBMCs) of ARC patients were investigated.

METHODS

The study population included 30 age-matched and sex-matched controls with 30 ARC patients aged 50 years and older. Acute oxidative stress was induced by 200 µM H₂O₂. The DNA damage was determined using gene-specific quantitative PCR-based assay in DNA extracted from PBMCs, both at basal condition and after (0, 6, and 20 h) acute oxidative stress.

RESULTS

Background level of mitochondrial DNA frequency was higher in cataract patients. The present study revealed that, for the first time, both nDNA and mtDNA of cataract patients were sensitive to the oxidative stress in comparison with healthy individuals. It was found that oxidative DNA damage in PBMCs was almost all repaired within 20 h. Also, time-dependent repair of nDNA and mtDNA damage was not different between cataract patients and healthy individuals.

CONCLUSIONS

Our findings clearly demonstrate that both nDNA and mtDNA in cataract patients are susceptible to oxidative DNA damage and background level of mitochondrial DNA damage was higher. Also, these results suggest that oxidative DNA damage accumulation (especially mtDNA damage) can play a crucial role in pathogenesis of cataract.

The estrogenic retina: The potential contribution to healthy aging and age-related neurodegenerative diseases of the retina

These last two decades have seen an explosion of clinical and epidemiological research, and basic research devoted to envisage the influence of gender and hormonal fluctuations in the retina/ocular diseases. Particular attention has been paid to age-related disorders because of the overlap of endocrine and neuronal dysfunction with aging. Hormonal withdrawal has been considered among risk factors for diseases such as glaucoma, diabetic retinopathy and age-related macular disease (AMD), as well as, for Alzheimer's disease, Parkinson's disease, or other neurodegenerative disorders. Sex hormones and aging have been also suggested to drive the incidence of ocular surface diseases such as dry eye and cataract. Hormone therapy has been approached in several clinical trials. The discovery that the retina is another CNS tissue synthesizing neurosteroids, among which neuroactive steroids, has favored these studies. However, the puzzling data emerged from clinical, epidemiological and experimental studies have added several dimensions of complexity; the current landscape is inherently limited to the weak information on the influence and interdependence of endocrine, paracrine and autocrine regulation in the retina, but also in the brain. Focusing on the estrogenic retina, we here review our knowledge on local 17β-oestradiol (E2) synthesis from cholesterol-based neurosteroidogenic path and testosterone aromatization, and presence of estrogen receptors (ERα and ERβ). The first cholesterol-limiting step and the final aromatase-limiting step are discussed as possible check-points of retinal functional/dysfunctional E2. Possible E2 neuroprotection is commented as a group of experimental evidence on excitotoxic and oxidative retinal paradigms, and models of retinal neurodegenerative diseases, such as glaucoma, diabetic retinopathy and AMD. These findings may provide a framework to support clinical studies, although further basic research is needed.

Age-related eye disease and gender

Worldwide, the prevalence of moderate to severe visual impairment and blindness is 285 millions, with 65% of visually impaired and 82% of all blind people being 50 years and older. Meta-analyses have shown that two out of three blind people are women, a gender discrepancy that holds true for both developed and developing countries. Cataract accounts for more than half of all blindness globally and gender inequity in access to cataract surgery is the major cause of the higher prevalence of blindness in women. In addition to gender differences in cataract surgical coverage, population-based studies on the prevalence of lens opacities indicate that women have a higher risk of developing cataract. Laboratory as well as epidemiologic studies suggest that estrogen may confer antioxidative protection against cataractogenesis, but the withdrawal effect of estrogen in menopause leads to increased risk of cataract in women. For the other major age-related eye diseases; glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy, data are inconclusive. Due to anatomic factors, angle closure glaucoma is more common in women, whereas the dominating glaucoma type; primary open-angle glaucoma (POAG), is more prevalent in men. Diabetic retinopathy also has a male predominance and vascular/circulatory factors have been implied both in diabetic retinopathy and in POAG. For AMD, data on gender differences are conflicting although some studies indicate increased prevalence of drusen and neovascular AMD in women. To conclude, both biologic and socioeconomic factors must be considered when investigating causes of gender differences in the prevalence of age-related eye disease.

Mutation rate estimation for 15 autosomal STR loci in a large population from Mainland China

STR, short tandem repeats, are well known as a type of powerful genetic marker and widely used in studying human population genetics. Compared with the conventional genetic markers, the mutation rate of STR is higher. Additionally, the mutations of STR loci do not lead to genetic inconsistencies between the genotypes of parents and children; therefore, the analysis of STR mutation is more suited to assess the population mutation. In this study, we focused on 15 autosomal STR loci. DNA samples from a total of 42,416 unrelated healthy individuals (19,037 trios) from the population of Mainland China collected between Jan 2012 and May 2014 were successfully investigated. In our study, the allele frequencies, paternal mutation rates, maternal mutation rates and average mutation rates were detected. Furthermore, we also investigated the relationship between paternal ages, maternal ages, area, the time of pregnancy and average mutation rate. We found that the paternal mutation rate was higher than the maternal mutation rate and the paternal, maternal, and average mutation rates had a positive correlation with paternal age, maternal age and the time of pregnancy respectively. Additionally, the average mutation rate of coastal areas was higher than that of inland areas.

•

15 autosomal STR loci were analyzed in a large scale population in Mainland China.

•

With increases of repeat units the event of loss is more than that of gain.

•

The paternal mutation rate is higher than the maternal mutation rate.

•

There is a positive correlation between mutation rates and age and pregnancy time.

•

The average mutation rates of coastal areas are higher than that of inland areas.