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Cross-sectional study investigating the prevalence and causes of vision impairment in Northwest Portugal using capture–recapture: [SV] Tvärsnittsstudie som undersöker prevalensen och orsakerna till synnedsättning i nordvästra Portugal med hjälp av infångning-återfångst[PT] Estudo transversal que investiga a prevalência e as causas da deficiência visual no Noroeste de Portugal utilizando captura-recaptura
Linnaeus University, Faculty of Health and Life Sciences, Department of Medicine and Optometry. University of Minho, Portugal.ORCID iD: 0000-0003-1280-9854
Universidade Nova de Lisboa, Portugal.
Universidade Nova de Lisboa, Portugal;London School of Hygiene and Tropical Medicine, UK.
University of Minho, Portugal.
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2022 (English)In: BMJ Open, E-ISSN 2044-6055, Vol. 12, no 9, article id e056995Article in journal (Refereed) Published
Abstract [en]

Objectives: The aim of this study was to estimate the prevalence and causes of vision impairment (VI) in Portugal.

Setting Information about people with VI was obtained from primary care centres, blind association (ACAPO) and from hospitals (the PCVIP study) in the Northwest of Portugal during a period spanning years 2014–2015. Causes of VI were obtained from hospitals.

Participants Administrative and medical records of people with visual acuity in the better seeing eye of 0.5 decimal (0.30logMAR) or worse and/or visual field less than 20° were investigated. Capture–recapture with log-linear models was applied to estimate the number of individuals missing from lists of cases obtained from available sources.

Primary and secondary outcome measures Log-linear models were used to estimate the crude prevalence and the category specific prevalence of VI.

Results Crude prevalence of VI was 1.97% (95% CI 1.56% to 2.54%), and standardised prevalence was 1% (95% CI 0.78% to 1.27%). The age-specific prevalence was 3.27% (95% CI 2.36% to 4.90%), older than 64 years, 0.64% (95% CI 0.49% to 0.88%), aged 25–64 years, and 0.07% (95% CI 0.045% to 0.13%), aged less than 25 years. The female-to-male ratio was 1.3, that is, higher prevalence among females. The five leading causes of VI were diabetic retinopathy, cataract, age-related macular degeneration, glaucoma and disorders of the globe.

Conclusions The prevalence of VI in Portugal was within the expected range and in line with other European countries. A significant number of cases of VI might be due to preventable cases and, therefore, a reduction of the prevalence of VI in Portugal seems possible. Women and old people were more likely to have VI and, therefore, these groups require extra attention. Future studies are necessary to characterise temporal changes in prevalence of VI in Portugal.No data are available. Raw data can be requested from the first author.

Abstract [sv]

Mål: Syftet med denna studie var att uppskatta förekomsten av och orsakerna till synnedsättning i Portugal.

Studieplats: Information om personer med VI erhölls från primärvårdscentraler, blindassociation (ACAPO) och från sjukhus (PCVIP-studien) i nordvästra Portugal under en period som sträckte sig över åren 2014–2015. Orsaker till synnedsättning erhölls från sjukhus.

Deltagare: Administrativa och medicinska journaler för personer med synskärpa i det bättre seende ögat på 0,5 decimal (0,30logMAR) eller sämre och/eller synfält mindre än 20° undersöktes. Capture-recapture med log-linjära modeller användes för att uppskatta antalet individer som saknas i listor över fall som erhållits från tillgängliga källor.

Primära och sekundära utfallsmått: Log-linjära modeller användes för att uppskatta den råa prevalensen och den kategorispecifika prevalensen av synnedsättning.

Resultat: Rå prevalens av synnedsättning var 1,97% (95% CI 1,56% till 2,54%), och standardiserad prevalens var 1% (95% CI 0,78% till 1,27%). Den åldersspecifika prevalensen var 3,27% (95% CI 2,36% till 4,90%), äldre än 64 år, 0,64% (95% CI 0,49% till 0,88%), i åldern 25–64 år och 0,07% (95% CI 0,045% till 0,13%), i åldern under 25 år. Förhållandet mellan kvinnor och män var 1,3, det vill säga högre prevalens bland kvinnor. De fem främsta orsakerna till synnedsättning var diabetisk retinopati, grå starr, åldersrelaterad makuladegeneration, glaukom och störningar i världen.

Slutsatser: Prevalensen av synnedsättning i Portugal låg inom det förväntade intervallet och i linje med andra europeiska länder. Ett betydande antal fall av synnedsättning kan bero på fall som kan förebyggas, och därför verkar en minskning av prevalensen av synnedsättning i Portugal möjlig. Kvinnor och gamla människor var mer benägna att ha synnedsättning och därför kräver dessa grupper extra uppmärksamhet. Framtida studier är nödvändiga för att karakterisera tidsmässiga förändringar i prevalensen av synnedsättning i Portugal.

*Detta abstrakt har maskinöversatts, osäkerheter kan uppstå

Abstract [pt]

Objetivos: O objetivo deste estudo foi estimar a prevalência e as causas da deficiência visual em Portugal.

Local de realização do estudo: Informação sobre pessoas com deficiência visual foi obtida a partir de centros de cuidados primários, associação ACAPO e de hospitais (via estudo PCVIP) no Noroeste de Portugal durante um período que se estendeu entre 2014 e 2015. As causas do deficiência visual foram obtidas apenas nos hospitais.

Participantes: Foram investigados registos administrativos e médicos de pessoas com acuidade visual no melhor olho de 0,5 decimal (0,30logMAR) ou pior e/ou campo visual inferior a 20°. Foi aplicado o metodo de captura-recaptura com modelos log-linear para estimar o número de pessoas que não constavam em nenhuma das listas de casos obtidos a partir de fontes disponíveis.

Resultados primários e secundários: Foram utilizados modelos log-linear para estimar a prevalência bruta e a prevalência específica da deficiência visual.

Resultados: A prevalência bruta de deficiência visual foi de 1,97% (95% CI 1,56% para 2,54%), e a prevalência padronizada foi de 1% (95% 1,78% para 1,27%). A prevalência específica da idade foi de 3,27% (95% CI 2,36% a 4,90%), mais de 64 anos, 0,64% (95% CI 0,49% para 0,88%), com idades compreendidas entre os 25 e os 64 anos e 0,07% (95% CI 0,045% para 0,13%), com menos de 25 anos. A racio entre mulheres e homens foi de 1,3, ou seja, maior prevalência no sexo feminino. As cinco principais causas de deficiência visual foram a retinopatia diabética, catarata, degeneração macular relacionada com a idade, glaucoma e desordens do globo.

Conclusões: A prevalência de deficiência visual em Portugal estava dentro do intervalo esperado e em linha com outros países europeus. Um número significativo de casos de deficiência visual pode estar relacionados com causas evitáveis e, portanto, uma redução da prevalência de deficiência visual em Portugal parece possível. As mulheres e os idosos são mais propensos a ter deficiência visual e, por conseguinte, estes grupos exigem uma atenção extra. São necessários mais estudos para caracterizar as mudanças temporais na prevalência de deficiência visual em Portugal.

Place, publisher, year, edition, pages
BMJ Publishing Group Ltd, 2022. Vol. 12, no 9, article id e056995
Keywords [en]
diabetic retinopathy, age-related macular degeneration, Diabetic macular oedema, vision impairment, low vision, prevalence, Portugal
Keywords [pt]
retinopatia diabética, degeneração macular relacionada à idade, edema macular diabético, deficiência visual, baixa visão, prevalência, Portugal
Keywords [sv]
diabetisk retinopati, åldersrelaterad makuladegeneration, diabetiskt makulaödem, synnedsättning, nedsatt syn, prevalens, Portugal
National Category
Ophthalmology
Research subject
Natural Science, Optometry
Identifiers
URN: urn:nbn:se:lnu:diva-113047DOI: 10.1136/bmjopen-2021-056995ISI: 000952044200011Scopus ID: 2-s2.0-85138202246OAI: oai:DiVA.org:lnu-113047DiVA, id: diva2:1660599
Note

Is included in the dissertation as a submitted manuscript titled: "Prevalence and causes of vision impairment in Norwest Portugal: a capture and recapture study"

Available from: 2022-05-24 Created: 2022-05-24 Last updated: 2023-08-28Bibliographically approved
In thesis
1. Studying prevalence using capture-recapture methods: visual impairment in Portugal
Open this publication in new window or tab >>Studying prevalence using capture-recapture methods: visual impairment in Portugal
2021 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Visual impairment (VI) due to eye diseases remains a significant healthproblem worldwide and, also, in Europe. There are an estimated 15 million peoplesuffering from moderate or severe visual impairment in Western Europe. VI has asignificant impact on the quality of life by reducing functional status and interferingwith the ability of the subject to maintain independence in a safe manner. Prevalenceof VI needs to be estimated regularly so that the progress of the vision health of apopulation can be evaluated and monitored. In addition, it is important to ascertainthe causes behind VI so that health programs can be designed to lower itsprevalence. There is currently a lack of epidemiological information about theprevalence and causes of VI in Portugal. Therefore, the aim of this thesis was todetermine the prevalence of VI in a large region Portugal using data from lists ofcases of VI.Capture-recapture models have been applied in several disciplines, asbiomedical sciences, epidemiology or ecology, to estimate the size of populations. Inparticular, they have been used to estimate the prevalence of several diseases orconditions. Developing these inferential models is of great importance to avoid thehigh costs and unreasonable time spending of cross-sectional studies. However,applying capture-recapture models is challenging, as they are very sensitive to listdependence and possible capture rates heterogeneity among subgroups of thepopulation. In particular, applying these models to human population samples isadditionally challenging, as in most epidemiologic studies only a small number oflists are available. There are two main differences between human and wildlifepopulations. First, human population lists generally have not a well-defined timeorder. Second, in wildlife studies there are often more trapping samples than inhuman population studies. In most epidemiologic surveys, only two to four lists areavailable. This can be problematic and is an additional difficulty when applyingcapture-recapture models in the context of human populations.The main objective of this work was to estimate the prevalence of VI usingcapture-recapture models. We estimated a crude prevalence of1.97%,95%CI=[1.56,2.54] to the Northwest of Portugal in the time period between2014 and 2015, specifically at the regions of Minho and Douro Litoral. Almost 2 ofevery 100 inhabitants of the Portuguese Northwest suffer from visual impairment.This prevalence value is in line with the values in some countries, particularly withSpain. Diabetic Retinopathy was the main cause (31%), followed by Cataract (15%),Age-related Macular Degeneration (14%) and Glaucoma (10%). This thesis provides asignificant contribution to the understanding of the CR methodology in human populations and for the knowledge of the epidemiological information about VI inPortugal.

Place, publisher, year, edition, pages
University of Minho, Portugal, 2021. p. 188
National Category
Ophthalmology
Research subject
Natural Science, Optometry
Identifiers
urn:nbn:se:lnu:diva-108705 (URN)
Supervisors
Available from: 2021-12-21 Created: 2021-12-21 Last updated: 2022-05-24Bibliographically approved

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Lima Ramos, PedroMacedo, António Filipe

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