Use of Cooking Fuels and Cataract in a Population-Based Study: The India Eye Disease Study.

BACKGROUND: Biomass cooking fuels are commonly used in Indian households, especially by the poorest socioeconomic groups. Cataract is highly prevalent in India and the major cause of vision loss. The evidence on biomass fuels and cataract is limited. OBJECTIVES: To examine the association of biomass cooking fuels with cataract and type of cataract. METHODS: We conducted a population-based study in north and south India using randomly sampled clusters to identify people ≥ 60 years old. Participants were interviewed and asked about cooking fuel use, socioeconomic and lifestyle factors and attended hospital for digital lens imaging (graded using the Lens Opacity Classification System III), anthropometry, and blood collection. Years of use of biomass fuels were estimated and transformed to a standardized normal distribution. RESULTS: Of the 7,518 people sampled, 94% were interviewed and 83% of these attended the hospital. Sex modified the association between years of biomass fuel use and cataract; the adjusted odds ratio (OR) for a 1-SD increase in years of biomass fuel use and nuclear cataract was 1.04 (95% CI: 0.88, 1.23) for men and 1.28 (95% CI: 1.10, 1.48) for women, p interaction = 0.07. Kerosene use was low (10%). Among women, kerosene use was associated with nuclear (OR = 1.76, 95% CI: 1.04, 2.97) and posterior subcapsular cataract (OR = 1.71, 95% CI: 1.10, 2.64). There was no association among men. CONCLUSIONS: Our results provide robust evidence for the association of biomass fuels with cataract for women but not for men. Our finding for kerosene and cataract among women is novel and requires confirmation in other studies. Citation: Ravilla TD, Gupta S, Ravindran RD, Vashist P, Krishnan T, Maraini G, Chakravarthy U, Fletcher AE. 2016. Use of cooking fuels and cataract in a population-based study: the India Eye Disease Study. Environ Health Perspect 124:1857-1862; http://dx.doi.org/10.1289/EHP193

EPHA2 Polymorphisms and Age-Related Cataract in India

Objective: We investigated whether previously reported single nucleotide polymorphisms (SNPs) of EPHA2 in European studies are associated with cataract in India. Methods: We carried out a population-based genetic association study. We enumerated randomly sampled villages in two areas of north and south India to identify people aged 40 and over. Participants attended a clinical examination including lens photography and provided a blood sample for genotyping. Lens images were graded by the Lens Opacification Classification System (LOCS III). Cataract was defined as a LOCS III grade of nuclear >= 4, cortical >= 3, posterior sub-capsular (PSC) >= 2, or dense opacities or aphakia/pseudophakia in either eye. We genotyped SNPs rs3754334, rs7543472 and rs11260867 on genomic DNA extracted from peripheral blood leukocytes using TaqMan assays in an ABI 7900 real-time PCR. We used logistic regression with robust standard errors to examine the association between cataract and the EPHA2 SNPs, adjusting for age, sex and location. Results: 7418 participants had data on at least one of the SNPs investigated. Genotype frequencies of controls were in Hardy-Weinberg Equilibrium (p > 0.05). There was no association of rs3754334 with cataract or type of cataract. Minor allele homozygous genotypes of rs7543472 and rs11260867 compared to the major homozygote genotype were associated with cortical cataract, Odds ratio (OR) = 1.8, 95% Confidence Interval (CI) (1.1, 3.1) p = 0.03 and 2.9 (1.2, 7.1) p = 0.01 respectively, and with PSC cataract, OR = 1.5 (1.1, 2.2) p = 0.02 and 1.8 (0.9, 3.6) p = 0.07 respectively. There was no consistent association of SNPs with nuclear cataract or a combined variable of any type of cataract including operated cataract. Conclusions: Our results in the Indian population agree with previous studies of the association of EPHA2 variants with cortical cataracts. We report new findings for the association with PSC which is particularly prevalent in Indians

Connexin Mediated Cataract Prevention in Mice

Cataracts, named for any opacity in the ocular lens, remain the leading cause of vision loss in the world. Non-surgical methods for cataract prevention are still elusive. We have genetically tested whether enhanced lens gap junction communication, provided by increased α3 connexin (Cx46) proteins expressed from α8(Kiα3) knock-in alleles in Gja8tm1(Gja3)Tww mice, could prevent nuclear cataracts caused by the γB-crystallin S11R mutation in CrygbS11R/S11R mice. Remarkably, homozygous knock-in α8(Kiα3/Kiα3) mice fully prevented nuclear cataracts, while single knock-in α8(Kiα3/−) allele mice showed variable suppression of nuclear opacities in CrygbS11R/S11R mutant mice. Cataract prevention was correlated with the suppression of many pathological processes, including crystallin degradation and fiber cell degeneration, as well as preservation of normal calcium levels and stable actin filaments in the lens. This work demonstrates that enhanced intercellular gap junction communication can effectively prevent or delay nuclear cataract formation and suggests that small metabolites transported through gap junction channels protect the stability of crystallin proteins and the cytoskeletal structures in the lens core. Thus, the use of an array of small molecules to promote lens homeostasis may become a feasible non-surgical approach for nuclear cataract prevention in the future

Retinol uptake by isolated retinal pigment epithelium plasma membranes

The uptake of retinol has been investigated by incubating suspensions of isolated bovine retinal pigment epithelium plasma membranes in the presence of [3H]retinol-retinol-binding protein complex. After SDS gel electrophoresis of the labelled membranes, [3H]retinol is found to be associated with a protein band of molecular weight 16000. The binding process is saturable, specific and shows a linear dependence on the membrane concentration in the incubation mixture. A dissociation constant of the order of 10-9 has been calculated for the retinol-receptor interaction. These observations confirm previous data obtained with isolated pigment epithelium cells and suggest the existence of an intermediate step, at the membrane level, in the transfer of retinol from its plasma carrier to the cell cytoplasm. © 1981 Academic Press Inc. (London) Ltd

Prevalence of Early and Late Age-Related Macular Degeneration in India: The INDEYE Study

PurposeTo describe the prevalence of early and late Age-Related Macular Degeneration (AMD) in older people in India. MethodsPeople aged 60 years and older identified using random cluster-sampling in 2 study centres in south and north India, attended an eye examination. Digital fundus images were graded at a single reading centre according to the International Classification System and were stratified into 5 exclusive stages. Results2821 people (79% response rate) in north India and 3079 (78%) in south India attended an eye examination. 27% of participants with photographs could not be graded, mainly due to dense opacities, and are included in the denominator of prevalence estimates. The prevalence of late AMD was 0.9% (95% CI 0.7-1.1) and similar in the two centres (p=0.452), comprising mainly of neovascular AMD (44 of 53 cases). For early AMD, the prevalence of stage 1 (soft distinct drusen or pigmentary irregularities) was 28.8% (95% CI 27.0-30.6) with no difference seen between the centres (p=0.113). Differences were observed for stage 2 (soft distinct drusen with pigmentary irregularities or soft indistinct or reticular drusen), 3.8% (95% CI 2.7-5.0) in north India and 6.0% (95% CI 5.2-6.7) in South India, and for stage 3 (soft indistinct or reticular drusen with pigmentary irregularities), 0.04% (95% CI 0-0.1) in north India and 0.3% (95% CI 0.1-0.6) in south India. ConclusionsThe prevalence of early AMD (stages 1 and 2) is similar to that observed in western populations but stage 3 and late AMD prevalence appear to be lower. These estimates however are conservative because of the high proportion of ungradeables

Prevalence of Lens Opacities in India: The INDEYE Study

PurposeTo describe the prevalence of lens opacities in older people in India. MethodsPeople aged 60 years and older identified using random cluster-sampling in 2 study centres in north and south India, attended an eye examination. Digital images of lens opacities were graded by type and severity using the Lens Opacity Classification System III (LOCS III). Any cataract was defined as LOCS III [&ge;]4 nuclear, [&ge;]3 cortical and [&ge;]2 posterior subcapsular, or dense ungradeable opacities or previously operated. Results2821 people (79% response rate) in north India and 3079 (78%) in south India attended an eye examination. The prevalence of any cataract was 73.6% (95% CI 72.0 - 75.2) and similar in the two centres (p=0.2). Type of cataract differed in prevalence between the centres: nuclear 60.0% (95% CI 56.9-63.1) in north India, 48.0% (95% CI 44.8-51.2) in south India; posterior subcapsular 26.5% (95% CI 24.4-28.5) in north India, 21.7% (95% CI 19.5-23.8) in south India; cortical 9.6% (95% CI 8.0-11.2) in north India and 12.8 % (95% CI 11.3-14.3) in south India. Prevalence of any cataract rose with age (54.9%, 95% CI 52.0-57.8 age group 60-64 years; 90.3%, 95% CI 88.9-91.8 age group 70 years and older, p<0.001) and was higher in women than in men (76.7%, 95% CI 74.9-78.5 women; 70.1%, 95% CI 68.0-72.1 men, p<0.001). Similar patterns with age and gender were observed for each type of cataract. ConclusionsCataract prevalence, especially posterior subcapsular cataract, is very high in older Indians compared to comparable age groups in western populations

Lens sodium channels are inactivated by anti-MIP26 antibodies

Sodium-specific channels can be functionally identified in phosphatidylcholine liposomes incorporating detergent-solubilized membrane proteins from pig lens epithelium and outer cortex. The transport of sodium is saturable, specific and protease-sensitive. MIP26 was identified in the solubilized membrane fraction and in the liposomes by means of Western blot analysis. Pre-treatment of liposomes with anti-MIP26 antiserum abolished the transport of sodium. These data indicate that MIP26 is associated to a sodium selective transport activity