Associations Between Plasma Levels of Vitamins and Cataract in the Italian-American Clinical Trial of Nutritional Supplements and Age-Related Cataract (CTNS): CTNS Report #2

Purpose: To investigate the association at baseline between plasma levels of selected vitamins and the presence and type of cataract in the participants in The Italian-American Trial of Nutritional Supplements and Age-related Cataract. Methods: At baseline, the participants (1020, 710 with “early cataract” and 310 with “no cataract,” 55–75 years of age) received an ocular examination, photographic lens grading, and measurement of plasma levels of vitamins A, C, E, beta-carotene, and of red blood cell glutathione reductase activity. Results: In multiple logistic models adjusted for potential confounders, high vitamin C levels were associated with a protective effect on nuclear (N) [OR: 0.54; 95% CI: 0.30, 0.97] and posterior subcapsular (PSC) cataract (OR: 0.37; 95% CI: 0.15, 0.93). High vitamin E levels were associated with increased prevalence of cortical cataract (C) (OR: 1.99; 95% CI: 1.02–3.90), PSC (OR: 3.27; 95% CI: 1.34, 7.96) and of any cataract (OR: 1.86; 95% CI: 1.08, 3.18). Conclusions: In agreement with some earlier studies, we found higher plasma levels of vitamin C to be associated with reduced prevalence of N and PSC cataracts. The finding of an increased prevalence of some types of cataract with higher levels of vitamin E was unexpected, has not been previously reported, and could be due to unadjusted confounding. The Italian-American Cataract Study Group*     

Lens retrodots and vacuoles and their associations with the prevalence and incidence of age-related cataract

Aim

To assess the prevalence of retrodots and vacuoles and their associations with the prevalence and long-term incidence of age-related cataract in an older Australian cohort.

Methods

Of 3654 baseline participants of the Blue Mountains Eye Study aged 49+ years (1992–1994), 2335 and 1952 were re-examined after 5 and 10 years, respectively. Lens photographs were graded for cataract, retrodots, and vacuoles. Eye-specific data were used to assess the associations between retrodots or vacuoles at baseline and the prevalence and 10-year incidence of nuclear, cortical, and posterior subcapsular (PSC) cataract and cataract surgery.

Results

At baseline, retrodots were present in 142 persons (4%) and vacuoles in 1333 persons (40%). Prevalence of both lens features increased with increasing age (Pfor trend <0.0001). After adjusting for age and gender, vacuoles were associated with prevalent PSC cataract at baseline (odds ratio (OR), 1.60, 95% confidence interval (CI), 1.25–2.05). After adjusting for age, gender, smoking, hypertension, diabetes, education, and use of inhaled/oral steroids, baseline retrodots were associated with an increased incidence of cataract surgery (OR 2.90, 95% CI 1.71–4.91), while 3+ vacuoles at baseline were associated with an increased risk of PSC cataract (OR 3.56, 95% CI 2.13–5.95) and cataract surgery (OR 1.84, 95% CI 1.22–2.77).

Discussion

Lens retrodots and vacuoles were found to be positively associated with 10-year incidence of cataract surgery, and vacuoles associated with PSC cataract, a finding suggestive of shared risk factors or pathogenesis between these two lens features and the development of PSC cataract.     

Plasma antioxidant vitamins and carotenoids and age-related cataract.

OBJECTIVE: To investigate the relationships between plasma concentrations of antioxidant vitamins and carotenoids and nuclear, cortical, and posterior subcapsular cataracts in a group of elderly men and women. DESIGN: Cross-sectional survey. PARTICIPANTS: Three hundred seventy-two men and women, aged 66 to 75 years, born and still living in Sheffield, England. METHODS: The Lens Opacities Classification System (LOCS) III was used to grade nuclear, cortical, and posterior subcapsular lens opacities. Fasting blood samples were taken to assess plasma concentrations of vitamin C, vitamin E, alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin, and beta-cryptoxanthin. MAIN OUTCOME MEASURES: Logistic regression analyses of the associations between plasma vitamin concentrations and cataract subtype, adjusting for age, gender, and other risk factors. RESULTS: After adjustment for age, gender, and other risk factors, risk of nuclear cataract was lowest in people with the highest plasma concentrations of alpha-carotene (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.3-0.9, P for trend 0.006) or beta-carotene (OR, 0.7; 95% CI, 0.4-1.4, P for trend 0.033). Risk of cortical cataract was lowest in people with the highest plasma concentrations of lycopene (OR, 0.4; 95% CI, 0.2-0.8, P for trend 0.003), and risk of posterior subcapsular cataract was lowest in those with higher concentrations of lutein (OR, 0.5; 95% CI, 0.2-1.0, P for trend 0.012). High plasma concentrations of vitamin C, vitamin E, or the carotenoids zeaxanthin and beta-cryptoxanthin were not associated with decreased risk. CONCLUSIONS: These findings suggest that a diet rich in carotenoids may protect against cataract development, but because they are based on observational data, they need to be confirmed in randomized controlled trials.     

Prevalence and associations of cataract in a rural Chinese adult population: the Handan Eye Study

Background

Cataract remains the leading cause of blindness and visual impairment in the world and in China. However, data on the prevalence of cataract based on standardized lens grading protocols from mainland China are limited. This paper estimated the age- and gender-specific prevalence and risk factor for cataract

Methods

In a population-based Chinese sample, participants underwent a comprehensive ophthalmic examination, including assessment of cortical, nuclear, posterior subcapsular (PSC) and mixed lens opacities from slit-lamp grading using the Lens Opacities Classification System III.

Results

Of the 7,557 eligible subjects, 6,830 took part in the study (90.4?% response rate), and 6,544 participants (95.8?%, mean age 52.0?±?11.8 years) had lens data for analyses. The prevalence of any cataract surgery in at least one eye was 0.8?% (95?% confidence interval [CI], 0.62, 1.06), with similar rates between men and women. The overall prevalence of any cataract or cataract surgery was 20.8?% (95?% CI, 19.8, 21.8), higher in women than in men after adjusting for age (23.6?% vs 17.6?%; OR: 1.78; 95?% CI: 1.54–2.07). When distinct lens opacity was categorized in each eye as cortical, nuclear, PSC or mixed, based on one randomly selected eye, cortical cataract was the most common distinct subtype (12.3?%), followed by mixed (3.2?%), nuclear (1.7?%), and PSC (0.2?%) cataract. The prevalence of all lens opacities increased with age (P?<?0.001). After excluding other causes for visual impairment, the proportion of people with best corrected visual acuity <20/60 was 21?% among those with PSC, and 12?% among those with mixed opacities in the better-seeing eye. In multivariable logistic regression models, myopia was associated with all cataract types, while higher fasting plasma glucose and diabetes were only associated with PSC cataract.

Conclusions

Cataract affects 20?% of the population aged 30 years and older living in rural China, with cortical cataract the most common subtype. Risk factors for cataract include myopia and diabetes.     

Fasting blood glucose levels and the long‐term incidence and progression of cataract – the Blue Mountains Eye Study

Purpose: To assess the associations between fasting blood glucose and the long‐term incidence and progression of cataract. Methods: A total of 3654 persons aged 49+ years were examined at baseline with fasting blood glucose measured, and 2454 re‐examined after 5 and/or 10 years. Lens photographs from each visit were used to assess cataract incidence and progression. Associations between baseline fasting blood glucose and incidence and progression of cortical, nuclear and posterior subcapsular (PSC) cataract were assessed using discrete logistic regression and change‐point models. Results: After adjusting for potential confounders, baseline fasting blood glucose was associated with the 10‐year incidence of cortical cataract with a threshold at blood glucose level of 6.0 mm (odds ratio [OR] 1.79, 95% confidence interval [CI] 1.25–2.57 for fasting glucose ≥6.0 mm compared to fasting glucose <6.0 mm). Each 1.0 mm increase in fasting glucose was also associated with higher 5‐year progression of PSC (OR 1.25, 95% CI: 1.15–1.35), 10‐year progression of cortical (OR 1.14, 95% CI: 1.01–1.27) and nuclear (OR 1.20, 95% CI: 1.01–1.43) cataract, with no thresholds detected. Conclusions: In this primarily nondiabetic older population, baseline fasting blood glucose was associated with the long‐term incidence of cortical cataract and long‐term progression of all three cataract subtypes.     

Five-year incidence of cataract in older persons with diabetes and pre-diabetes

PURPOSE: To investigate longitudinal associations between diabetes and the 5-year incidence of cataract and cataract surgery. (A population-based, cohort study of 2335 persons with baseline ages 49 years or older resident in the Blue Mountains region, west of Sydney, Australia). METHODS: Baseline information on diabetes history was collected during an interviewer-administered questionnaire. Impaired Fasting Glucose (IFG) was defined as venous plasma glucose between 6.0 and 7.0 mmol/L and newly diagnosed diabetes as plasma glucose >7.0 mmol/L, using fasting blood glucose measurements taken at baseline. Retroillumination lens photographs from the baseline and 5-year follow-up examinations were graded for presence of cortical, posterior subcapsular (PSC) and nuclear cataract. RESULTS: We found a 2-fold higher 5-year incidence of cortical cataract in participants with IFG, multivariate adjusted odds ratio (OR) 2.2, 95% confidence interval (CI) 1.1-4.1. Incident PSC cataract was more frequent among persons with diabetes, but this association was statistically significant only for those with newly diagnosed diabetes, multivariate adjusted OR 4.5 (CI 1.5-13.0). There were no statistically significant associations found between incident nuclear cataract or cataract surgery and either diabetes or IFG. CONCLUSIONS: These epidemiological data suggest that IFG, a pre-diabetic condition, may be a risk factor for the development of cortical cataract.     

Dietary macronutrient intake and five-year incident cataract: the blue mountains eye study

PURPOSE: To investigate the relationships between dietary macronutrient intake at baseline and the five-year incidence of the three main types of cataract in older people. DESIGN: Population-based cohort study. METHODS: Settings: An urban community near Sydney, Australia. STUDY POPULATION: The Blue Mountains Eye Study (BMES) examined 3,654 predominantly Caucasian participants aged 49+ years during 1992 to 1994, and then 2,335 survivors (71.5%) after five years. Of these 2,335 subjects, 1988 (85%) completed a Willett-derived food frequency questionnaire (FFQ) at baseline. OBSERVATION PROCEDURES: A 145-item FFQ was used to assess nutrient intakes and lens photography was used to assess the presence of cataract at both time points. MAIN OUTCOME MEASURES: Incidence of cortical, nuclear, and posterior subcapsular (PSC) cataract was assessed via lens photographic grading following the Wisconsin cataract grading method. RESULTS: After adjusting for multiple known cataract risk factors, higher dietary intakes of omega-3 polyunsaturated fatty acids (n-3 PUFA) were associated with a reduced incidence of nuclear cataract. The odds ratio (OR) for subjects in the highest quintile of intake compared to those in the lowest quintile was 0.58 (95% confidence interval [CI] 0.35 to 0.97), P(trend) = .027. Similarly, for PSC cataract, higher dietary intakes of protein were protective (OR 0.28; 95% CI 0.10 to 0.76), P(trend) = .015. Dietary macronutrient intake was not associated with incident cortical cataract. CONCLUSIONS: Higher dietary intakes of n-3 PUFA may decrease the five-year risk of nuclear cataract, whereas higher dietary intakes of protein may decrease risk for PSC cataract.     

The potential role of nutrition on lens pathology: a systematic review and meta-analysis

Oxidative stress is one of the main mechanisms of lens opacification, and certain nutritional antioxidants are suspected to have a protective effect. To examine the role of these nutritional antioxidants on cataract prevention, we searched major databases and reviewed current evidence regarding the protective effect of nutritive antioxidants. We included observational studies that investigate the association between one or more of the following micronutrients and cataract: vitamin A, vitamin C, vitamin E, lutein, zeaxanthin, α- and β-carotene. Two independent authors extracted data and assessed their quality. We pooled results for overall cataract incidence for all types of cataract and separately for nuclear, cortical, and posterior subcapsular cataract. We did not perform sensitivity analysis. Twenty-five studies were included in the qualitative and 24 in the quantitative part of the study, with a total of 295,821 participants over 30 years old. Results from pooled analysis showed a protective effect of antioxidants on cataract, but not all of them reached statistical significance. Statistically significant results were reached for vitamin C (odds ratio [OR] = 0.88, 95% confidence interval [CI] [0.81, 0.97]), beta-carotene (OR = 0.89, 95% CI [0.83, 0.95]), and lutein and zeaxanthin (OR = 0.92, 95% CI [0.85, 0.99]). We did not find statistically significant results for vitamin E (OR = 0.84, 95% CI [0.70, 1.01]), vitamin A (OR = 0.90, 95% CI [0.80, 1.00]), or alpha-carotene (OR = 0.92, 95% CI [0.85, 1.00]). The present study shows a relation between certain antioxidants and cataract, but further studies, especially interventional, are needed to confirm this hypothesis.     

Prevalence of Lens Opacities in Asian Malays

Purpose: To describe the prevalence of lens opacities and cataract surgery in an older Malay population in Singapore.

Methods: The Singapore Malay Eye Study is a population-based cross-sectional study of 3280 (78.7% response rate) Malay adults aged 40–80 years. Participants underwent a standardized clinical eye examination. Digital slit-lamp and retroillumination photographs were taken of both eyes of each participant and graded for age-related nuclear, cortical and posterior subcapsular (PSC) cataract, following the Wisconsin Cataract Grading System. Other lens opacities, including retrodots and vacuoles, were also graded. Information on medical and lifestyle factors was collected using questionnaires. The study sample was directly age-standardized to the Malay population in Singapore using the 2000 Singapore population census.

Results: A total of 3054 (97.7%) and 3113 (99.6%) participants had gradable Topcon slit lamp and Neitz photographs, respectively. The overall age-adjusted prevalence of any cataract was 29.1%, and that of nuclear, cortical and PSC cataract were 12.9% (95% confidence interval, CI, 11.2–13.1%), 21.2% (95% CI 19.8–22.7%) and 9.7% (95% CI 8.8–10.8%), respectively. Age-adjusted prevalence of cataract surgery was 4.7% (95% CI 4.2–5.4%). Prevalence of all three cataract types and cataract surgery increased with age. Age-adjusted prevalence for retrodots and vacuoles were 19.7% (95% CI 18.3–21.1%) and 64.3% (95% CI 61.1–67.6%), respectively. Retrodots were found to be associated with prevalence of all three cataract types, while vacuoles were associated with cortical and PSC cataract prevalence.

Conclusion: Lens opacities were common in this urban Malay population. Retrodots and vacuoles were found to be associated with age-related cataract.     

Risk factors for age related cataract in a rural population of southern India: the Aravind Comprehensive Eye Study

AIM: To determine risk factors for lens opacities and age related cataract in an older rural population of southern India. METHODS: A cross sectional population based study of 5150 people aged 40 years and above from 50 clusters from three districts in southern India. The lens was graded and classified after dilation using LOCS III system at the slit lamp for cataract. Definite cataract was defined as nuclear opalescence >/=3.0 and/or cortical cataract >/=3.0 and/or PSC >/=2.0. RESULTS: Definite cataracts were found in 2449 (47.5%) of 5150 subjects and the prevalence of cataract increased with age. The age adjusted prevalence of cataract was significantly lower in males (p = 0.0002). Demographic risk factors-increasing age and illiteracy-were common for the three subtypes of cataract; females were more likely to have cortical cataracts and nuclear cataracts. Additionally, nuclear cataracts were associated with moderate smoking (OR:1.28, 95% CI:1.01 to 1.64), lean body mass indices (OR: 1.37, 95% CI: 1.17 to 1.59) and higher waist to hip ratios (OR: 0.67, 95% CI: 0.54 to 0.82); cortical cataracts with hypertension (OR: 1.39 95% CI:1.11 to 1.72), pseudoexfoliation (OR:1.53,95% CI:1.17 to 2.01), and moderate to heavy smoking; and posterior subcapsular cataracts with diabetes (OR:1.55, 95% CI:1.12 to 2.15), lean body mass (OR:1.32, 95% CI:1.11 to 1.57), and high waist to hip ratios (OR: 0.77, 95% CI: 0.62 to 0.94). CONCLUSIONS: Risk factors for age related cataract in this population do not appear to be different from those reported in other populations. Further studies are required to identify the reason for the high prevalence of age related cataract and to understand better the role of each risk factor for cataractogenesis in this population.     

Diet and cataract: the Blue Mountains Eye Study

PURPOSE: To investigate relationships between a wide range of macro- and micronutrients, including antioxidant vitamins, and the three main types of cataract in older people. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Two thousand nine hundred people aged 49 to 97 years living in an urban community near Sydney, Australia. TESTING: Food frequency questionnaires and lens photography. MAIN OUTCOME MEASURE: Lens photographs were graded for presence and severity of cortical, nuclear, and posterior subcapsular cataracts. RESULTS: Higher intakes of protein, vitamin A, niacin, thiamin, and riboflavin were associated with reduced prevalence of nuclear cataract. After adjusting for multiple known cataract risk factors, the odds ratios for those in the highest intake quintile groups compared to those in the lowest intake quintiles were 0.5 (95% confidence interval [CI], 0.3-0.8) for protein, 0.5 (95% CI, 0.3-0.9) for vitamin A, 0.6 (95% CI, 0.4-0.9) for niacin, 0.6 (95% CI, 0.4-0.9) for thiamin, and 0.5 (95% CI, 0.3-0.9) for riboflavin. Intake of polyunsaturated fats was associated with reduced prevalence of cortical cataract. No nutrients were associated with posterior subcapsular cataract. CONCLUSIONS: The nucleus of the lens is particularly sensitive to nutrient deficiencies. Protein, vitamin A, niacin, thiamin, and riboflavin protected against nuclear cataract in this study.     

Smoking and its association with cataract: results of the Andhra Pradesh eye disease study from India

PURPOSE: To investigate the associations between tobacco smoking and various forms of cataracts among the people of a state in India. METHODS: A population-based cross-sectional epidemiologic study was conducted in the south Indian state of Andhra Pradesh (AP). A total of 10,293 subjects of all ages from one urban and three rural areas, representative of the population of AP, were interviewed, and each underwent a detailed dilated ocular evaluation by trained professionals. Data were analyzed for 7416 (72%) of the subjects aged >15 years. RESULTS: Increasing age was significantly associated with all cataract types and history of prior cataract surgery and/or total cataract. In multivariate analyses, after adjusting for all demographic factors and for history of smoking, females, illiterate persons, and those belonging to the extreme lower socioeconomic status group were found to have a significantly higher prevalence of any cataract, adjusted odds ratio (OR)=1.60 (95% confidence interval [CI]: 1.24-1.96), 1.46 (95% CI: 1.17-1.70), and 1.92 (95% CI: 1.14-3.24), respectively. After adjustment, cigarette and cigar smokers had a significantly higher prevalence of any cataract, adjusted OR=1.51 (95% CI: 1.10-2.06) and 1.44 (95% CI: 1.12-1.84), respectively, compared with those who had never smoked ("never-smokers"). A significantly higher prevalence of nuclear, cortical cataract, and history of prior cataract surgery and/ or total cataract was found among cigarette smokers. A dose-response relationship was seen with respect to cigarette and cigar smoking. After adjustment, compared with never-smokers, cigarette smokers who smoked heavily (>14 "pack-years" of smoking) had a significantly higher prevalence of nuclear cataract (OR=1.65; 95% CI: 1.10-2.59), cortical cataract (OR=2.11; 95% CI: 1.38-3.24), and history of prior cataract surgery and/or total cataract (OR=2.10; 95% CI: 1.05-4.22). Nuclear cataract was significantly higher in cigar smokers (adjusted OR=1.55; 95% CI: 1.16-2.01) and in cigar smokers who smoked heavily (>21 person-years of smoking; OR=1.50; 95% CI: 1.10-1.95), compared with never-smokers. CONCLUSIONS: Consistent with other studies, tobacco smoking was strongly associated with a higher prevalence of nuclear and cortical cataracts and history of prior cataract surgery in this population. These findings suggest yet another need to educate the community on the importance of cessation of tobacco smoking and perhaps incorporating an antismoking message into school health programs.     

Diabetes,fasting blood glucose and age-related cataract: the Blue Mountains Eye Study

AIMS. To examine the relationship between diabetes and the presence of cortical, nuclear and posterior subcapsular (PSC) cataract in a defined older population, while controlling for known cataract risk factors. METHODS. Slit-lamp and retroillumination lens photographs were taken on 3654 participants attending the population-based Blue Mountains Eye Study during 1992-94. Masked grading of the photographs was performed using the Wisconsin Cataract Grading System. RESULTS. 217 subjects (5.9% of the population) had previously diagnosed diabetes and 66 (1.8%) had diabetes diagnosed from fasting blood glucose measurements. Cortical cataract, PSC and past cataract surgery were associated with known diabetes in age-sex adjusted models. However, only PSC (odds ratio (OR) 1.8, 95% confidence interval (CI) 1.0-3.1) and past cataract surgery (OR 2.5, CI 1.5-4.2) remained statistically significantly associated with diabetes after further adjustment for other known cataract risk factors. Increasing therapy, as an index of diabetes severity (oral or insulin treatment, compared to treatment by diet alone), was associated with a markedly increased risk of PSC (OR 5.4). CONCLUSIONS. These findings support previous research showing that diabetes has a harmful effect on the lens. The markedly increased risk for PSC may also have been reflected in the association found between diabetes and past cataract surgery. Contrary to findings from the Beaver Dam Eye Study, we found only a weak association with cortical cataract, which was not statistically significant after adjusting for other known cataract risk factors.     

Lutein and zeaxanthin and the risk of cataract: the Melbourne visual impairment project

PURPOSE: To evaluate the association of cortical, nuclear, or posterior subcapsular (PSC) cataract with dietary intake of lutein-zeaxanthin (LZ) in a population-based sample. METHODS: For the study, 3271 (83% of the eligible residents) permanent residents aged > or =40 years were recruited in 1992 to 1994 via a cluster random sampling. In 1997 to 1999, 2594 (79%) attended the follow-up examination including lens photography, a life-style questionnaire, and a food-frequency questionnaire (FFQ). Cases were those with cortical opacity > or =4/16, nuclear opacity grade > or =2.0, or PSC opacity > or =1 mm2. Logistic regression was used to calculate the odds ratios for cataract by daily LZ intake, or its quintile indicator with the lowest quintile as the baseline category, controlling for energy-adjusted fat intake and variables previously found to be associated with the cataract outcomes. RESULTS: Of the 2322 participants who attended the follow-up survey and completed the FFQ, 1841 (79%), 1955 (84%), and 1950 (84%) were included in the analyses of cortical, nuclear, and PSC cataract, respectively. There were 182 (9.9%), 387 (19.8%), and 177 (9.1%) cases for cortical, nuclear, and PSC cataract, respectively. Cortical and PSC cataract were not significantly associated with LZ intake. For nuclear cataract the odds ratios were 0.67 (0.46-0.96) and 0.60 (0.40-0.90) for every 1-mg increase in crude and energy-adjusted daily LZ intake, respectively. The odds ratios (95% CI) for those in the top quintile of crude LZ intake was 0.58 (0.37-0.92; P = 0.023 for trend), and it was 0.64 (0.40-1.03) for energy adjusted LZ intake (P = 0.018 for trend). CONCLUSIONS: This study found an inverse association between high dietary LZ intake and prevalence of nuclear cataract.     

Associations of cataract with antioxidant enzymes and other risk factors: the French Age-Related Eye Diseases (POLA) Prospective Study

PURPOSE: To determine the association of potential risk factors, including antioxidant enzymes, with the incidence of cataract. DESIGN: Cohort study. PARTICIPANTS: At baseline, the Age-Related Eye Diseases (Pathologies Oculaires Liées à l'Age, POLA) Study included 2584 residents of Sète (southern France) aged 60 years or older. From September 1998 to May 2000, a 3-year follow-up examination was performed on 1947 of the 2436 surviving participants (79.9%). METHODS: Cataract classification was based on a standardized lens examination at the slit lamp, according to Lens Opacities Classification System III. Biologic measurements were performed at baseline from fasting blood samples. MAIN OUTCOME MEASURES: At baseline and follow-up, the presence of cataract was defined as: NC or nuclear opalescence (NO) > or = 4 for nuclear cataract, C > or = 4 for cortical cataract, and P > or = 2 for posterior cataract (PSC) opacities, using opacity grades corrected for interobserver variability. Incidence rates were assessed separately for right and left eyes and for each type of cataract. RESULTS: In the multivariate model, the incidence of cortical cataract was increased in subjects with high red blood cell superoxide dismutase activity (odds ratio [OR] 4.2 [1.5-12.1], P = 0.007). The incidence of PSC cataract was increased in subjects with a high level of plasma glutathione peroxidase (OR 1.8 [1.0-3.3], P = 0.05). In addition to age, gender, and opacities at baseline, significant risk factors for incident cataract were: long-duration diabetes (OR 5.8, P = 0.001 for cortical cataract) and lifetime heavy smoking (OR 2.9, P = 0.006 for PSC cataract). CONCLUSIONS: Consistent with the baseline analysis, the results of this prospective study suggest that antioxidant enzymes might be implicated in the etiology of cataract.     

Refractive associations with cataract: the Blue Mountains Eye Study.

PURPOSE: To assess the relationship between myopia and age-related cataract in a defined older population. METHODS: A cross-sectional study of 3654 people aged 49 to 97 years was conducted in the Blue Mountains near Sydney, Australia, from 1992 through 1994. General medical, eye, and refractive history and information about confounders were collected by questionnaire. Participants had a detailed determination of refraction, and the spherical equivalent refraction of each eye was calculated. The Wisconsin Cataract Grading System was used in masked grading of slit lamp and retroillumination lens photographs, to assess presence and severity of nuclear, cortical, and posterior subcapsular (PSC) cataract. Data from both eyes were analyzed by the generalized estimating equation method, adjusting for cataract risk factors. RESULTS: Included in the analysis were 7308 eyes. A history of wearing distance glasses, excluding eyes with current hyperopic refraction, was used as a proxy for myopia. Subjects who had worn distance glasses were more likely to have nuclear cataract (odds ratio [OR] 1.3; confidence interval [CI] 1.0-2.1). After stratification by age at first wearing distance glasses, this relationship remained only for people who first wore distance glasses after age 40 years (OR 1.3; CI 1.0-1.8), which suggested a myopic refractive shift from developing nuclear opacity and was supported by the weak association found between current myopic refraction and nuclear cataract (OR 1.3; CI 1.0-1.6). Eyes with onset of myopia before age 20 years had the greatest PSC cataract risk (OR 3.9; CI 2.0-7.9). This was supported by the finding of an association between current myopic refraction and PSC cataract (OR 2.5; CI 1.6-4.1). PSC cataract was inversely associated with hyperopia (OR 0.6; CI 0.4-0.9). Refraction-related increasing odds were found between PSC cataract and myopia: low myopia (OR 2.1; CI 1.4-3.5), moderate myopia (OR 3.1; CI 1.6-5.7), and high myopia (OR 5.5; CI 2.8-10.9). High myopia was associated with PSC, cortical, and late nuclear cataract. CONCLUSIONS: Early-onset myopia (before age 20 years) may be a strong and independent risk factor for PSC cataract. The findings suggest the possibility of a dose response between levels of myopia and PSC cataract. Nuclear cataract was associated with presumed acquired myopia, whereas high myopia was associated with all three types of cataract.     

Cardiovascular disease,vascular risk factors and the incidence of cataract and cataract surgery: The Blue Mountains Eye Study

PURPOSE To assess whether an association exists between cardiovascular disease, vascular risk factors and incident cataract and cataract surgery. METHODS The Blue Mountains Eye Study examined 3654 participants =49 years of age during 1992–4, then 2335 survivors (75.1%) after five years. Trained interviewers administered a vascular history questionnaire; height, weight and blood pressure were measured. Lens photographs from both examinations were graded for presence of cortical, nuclear or posterior subcapsular cataract. RESULTS Obesity (body mass index =30kg/m 2 ) was significantly associated with increased incidence of both cortical [odds ratio (OR) 1.6, 95% confidence interval (CI) 1.2–2.2] and posterior subcapsular cataract (OR 2.1, CI 1.2–3.7). Hypertensive participants using medication and aged less than 65 years at baseline had a higher incidence of posterior subcapsular cataract (OR 3.4, 95% CI 1.3–8.4) than normotensive subjects. A history of angina was associated with higher cataract surgery incidence (OR 2.1, 95% CI 1.3–3.5). CONCLUSIONS These longitudinal data provide some evidence supporting a relationship between cardiovascular disease, vascular risk factors and incident cataract and cataract surgery. The findings confirm a number of associations previously documented in cross-sectional data.     

Plasma homocysteine, serum folic acid, serum vitamin B12, serum vitamin B6, MTHFR and risk of pseudoexfoliation glaucoma: a meta-analysis

Background

The aim of this meta-analysis is to explore the relationship between plasma total homocysteine (tHcy) levels, serum folic acid, vitamin B12 and vitamin B6 levels, methylenetetrahydrofolate reductase (MTHFR) C677T genotype and risk of pseudoexfoliation glaucoma (PEXG).

Methods

A systematic search of EMBASE and PubMed of relevant articles was carried out for all published articles. Main outcome measures included the calculation of plasma tHcy levels, serum folic acid, vitamin B12, and vitamin B6 levels mean difference and odds ratios (OR) of MTHFR C677T genotype between cases and controls.

Results

There were 14 studies for tHcy (485 cases and 456 controls), five studies for folic acid (188 cases and 189 controls), six studies for vitamin B12 (199 cases and 225 controls), three studies for vitamin B6 (128 cases and 130 controls) and eight studies for MTHFR (479 cases and 661 controls). Overall, the mean plasma tHcy levels in cases was 3.38?umol/l (95% confidence intervals (CI): 2.35–4.42) higher than in controls. Serum folic acids, but not vitamin B12 and vitamin B6 levels, was significantly lower in cases than in controls; the weighted mean differences with 95% CI were ?1.50?umol/l (?2.53, ?0.46), ?36.29?umol/l (?81.27, 8.68) and ?0.60?umol/l (?2.55, 1.35) respectively. There was no evidence of association between the MTHFR C677T genotype and PEXG (OR?=?1.28, 95% CI: 0.85, 1.93).

Conclusions

PEXG is associated with elevated plasma tHcy and low serum folic acid levels, but not serum vitamin B12, vitamin B6 levels, and MTHFR C677T genotype.     

Risk factors for age-related maculopathy in a 14-year follow-up study: the Copenhagen City Eye Study

PURPOSE: To examine the association between potential risk factors and the 14-year incidence of age-related maculopathy (ARM). DESIGN: Population-based cohort study. PARTICIPANTS: At baseline, 946 volunteers participated in the study during 1986--88. These subjects were between 60 and 80 years of age and lived in the ?sterbro district of Copenhagen. Excluding participants who had died since baseline, 359 subjects (97.3% of survivors) were re-examined 14 years later, during 2000--2002. A total of 31.8% (301/946) of the original material was included in the risk factor analyses. METHODS: Participants underwent an ophthalmological examination at Rigshospitalet, the National University Hospital of Copenhagen. Similar standardized protocols for physical examination were used at the baseline and follow-up examinations. Age-related maculopathy lesions were determined by the same grader grading colour fundus photographs from both examinations using a modification of the Wisconsin Age-related Maculopathy Grading System protocol. RESULTS: Of the 359 participants, 94 had incident early ARM and 52 had incident late ARM at follow-up in either eye. In logistic regression, the risk factors for early ARM or worse were as follows: cataract (odds ratio [OR] 2.8, 95% confidence interval [CI] 1.2-6.2); family history of ARM (OR 4.5, 95% CI 1.3--15.5), and alcohol consumption >250 g/week (OR 4.6, 95% CI 1.1-19.2). High levels of apolipoprotein B (>100 mg/l) decreased the risk of development of early ARM or worse (OR 0.4, 95% CI 0.2-0.8), while high levels of apolipoprotein A1 (>or= 150 mg/l) increased the risk of late ARM (OR 2.5, 95% CI 1.2-5.3). Advanced age at baseline was also associated with the incidence of late ARM (OR 2.0, 95% CI 1.4-2.9). CONCLUSIONS: These findings indicate a direct correlation between age, cataract, family history, alcohol consumption, the apolipoproteins A1 and B and the 14-year incidence of ARM.     

Plasma lutein and zeaxanthin and other carotenoids as modifiable risk factors for age-related maculopathy and cataract: the POLA Study

PURPOSE: To assess the associations of plasma lutein and zeaxanthin and other carotenoids with the risk of age-related maculopathy (ARM) and cataract in the population-based Pathologies Oculaires Liées à l'Age (POLA) Study. METHODS: Retinal photographs were graded according to the international classification. ARM was defined by the presence of late ARM (neovascular ARM, geographic atrophy) and/or soft indistinct drusen (>125 microm) and/or soft distinct drusen (>125 microm) associated with pigmentary abnormalities. Cataract classification was based on a direct standardized lens examination at the slit lamp, according to Lens Opacities Classification System III. Plasma carotenoids were measured by high-performance liquid chromatography (HPLC), in 899 subjects of the cohort. RESULTS: After multivariate adjustment, the highest quintile of plasma zeaxanthin was significantly associated with reduced risk of ARM (OR=0.07; 95% CI: 0.01-0.58; P for trend=0.005), nuclear cataract (OR=0.23; 95% CI: 0.08-0.68; P for trend=0.003) and any cataract (OR=0.53; 95% CI: 0.31-0.89; P for trend=0.01). ARM was significantly associated with combined plasma lutein and zeaxanthin (OR=0.21; 95% CI: 0.05-0.79; P for trend=0.01), and tended to be associated with plasma lutein (OR=0.31; 95% CI: 0.09-1.07; P for trend=0.04), whereas cataract showed no such associations. Among other carotenoids, only beta-carotene showed a significant negative association with nuclear cataract, but not ARM. CONCLUSIONS: These results are strongly suggestive of a protective role of the xanthophylls, in particular zeaxanthin, for the protection against ARM and cataract.