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Risk factors for corneal ulcers: a population-based matched case–control study in Nepal
  1. Raghunandan Byanju1,
  2. Ram Prasad Kandel1,2,
  3. Bimal Poudyal1,
  4. Sadhan Bhandari1,
  5. Anju Ligal1,
  6. Sangita Pradhan1,
  7. Maria Gautam1,
  8. Puspa Shrestha1,
  9. Ranjeet Kumar Sah1,
  10. John A Gonzales3,4,
  11. Travis C Porco3,5,
  12. John P Whitcher3,
  13. Muthiah Srinivasan6,
  14. Madan Prasad Upadhyay7,
  15. Thomas M Lietman3,4,5,8,
  16. Jeremy David Keenan3,4,
  17. Kieran S O'Brien3,4,5,8
  18. The Village-Integrated Eye Worker Trial Group
    1. 1 Bharatpur Eye Hospital, Bharatpur, Nepal
    2. 2 Seva Foundation, Berkeley, California, USA
    3. 3 Francis I. Proctor Foundation, University of California, San Francisco, California, USA
    4. 4 Department of Ophthalmology, University of California, San Francisco, California, USA
    5. 5 Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
    6. 6 Cornea, Aravind Eye Care System, Madurai, India
    7. 7 BP Eye Foundation, Kathmandu, Nepal
    8. 8 Institute for Global Health Sciences, University of California, San Francisco, California, USA
    1. Correspondence to Dr Kieran S O'Brien, University of California San Francisco, San Francisco, USA; kieran.obrien{at}ucsf.edu

    Abstract

    Background/aims We aimed to examine risk factors for corneal ulcer in a rural and peri-urban setting in Nepal.

    Methods This population-based matched case–control study was nested in a cluster randomised trial in 24 village development committees in Nepal. Incidence density sampling was used to match incident corneal opacity cases to controls, matching on time of opacity, age, sex and location. Cases and controls were invited to participate in a survey of risk factors for corneal ulcer. Risk factors were evaluated using conditional logistic regression to account for matching.

    Results Of the 540 participants with incident opacities identified in the trial, 433 were willing to participate in this substudy and matched to a control. Compared with controls, cases had lower odds of having any education vs no education (adjusted OR, aOR 0.60, 95% CI 0.39 to 0.94), working in non-manual labour occupations vs manual labour occupations (aOR 0.64, 95% CI 0.42 to 0.95) and preferring medical shops for ocular trauma versus eye care system centres (aOR 0.58, 95% CI 0.37 to 0.92). Cases had higher odds of protective goggle use versus no protection (aOR 3.8, 95% CI 1.3 to 11.0) and having an ocular injury vs none (aOR 7.7, 95% CI 4.3 to 13.6) compared with controls.

    Conclusion We found ocular injury, manual labour and lower education to be strongly associated with the development of corneal ulcer. Given the persistent burden of corneal blindness in this area, prevention efforts could target efforts to increase access to care in areas where these factors are common.

    • cornea
    • epidemiology
    • public health

    Data availability statement

    Data are available on reasonable request. Deidentified data associated with these analyses will be made available on reasonable request to the corresponding author.

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    Data availability statement

    Data are available on reasonable request. Deidentified data associated with these analyses will be made available on reasonable request to the corresponding author.

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    Footnotes

    • RB and RPK contributed equally.

    • Collaborators Collaborative members names are provided in online supplemental file 2.

    • Contributors RPK, RB, SB, TCP, JPW, SM, MPU, TML, JDK and KSO'B contributed to the conception and design of the study. RB, RPK, BP, SB, AL, SP, MG, PS, RKS, JG, TML, JDK and KSO'B contributed to the implementation of the study including data collection. KSO'B conducted the data analyses and drafted the initial manuscript. JDK and KO'B accept full responsibility for the work, had access to the data, and jointly controlled the decision to publish.

    • Funding This work was supported by the National Eye Institute of the National Institutes of Health (NEI-NIH U10EY022880), Research to Prevent Blindness, the Peierls Foundation and the Alta California Eye Research Foundation.

    • Competing interests None declared.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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