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The Study

Smoking and age related macular degeneration: the number of pack years of cigarette smoking is a major determinant of risk for both geographic atrophy and choroidal neovascularisation

In simple terms

This study looked at people who already had eye damage and asked them if they smoked, then compared them to people without the damage. It found that people who smoked more were more likely to have the eye problem, but it didn't prove smoking caused it — maybe other things like diet or genes played a role too.

58%

Analysis score

58/ 58

Maximum 58 for a case-control study.

Where the score came from

Reporting40
Methodology43
Publication100
Statistical77
Study type (basis of the score)
Case-Control Study
Level 3b - Individual case-control study
What’s the bottom line?

This study looked at how smoking affects the back of the eye, where vision problems happen in older people.

Where does this study sit?

Reviews of RCTs (Meta-analyses)

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Case-Control Studies
Level 3b
58

58 / 100

Quality score

Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.

Cannot establish causation

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Key takeaways

Summary

Based on the study abstract and findings.

  1. 1Yes — this means smoking heavily can seriously damage your vision as you get older, but quitting for a long time can undo that risk, and even breathing other people’s smoke can hurt your eyes.
  2. 2People who smoked more than 40 pack-years (like 2 packs a day for 20 years) were over 2.5 times more likely to get severe vision loss.
  3. 3Those who quit smoking for over 20 years had the same risk as people who never smoked.
  4. 4Even people who never smoked but lived with a smoker for 5+ years had nearly double the risk.

Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data

Publication

Journal

British Journal of Ophthalmology

Year

2005

Authors

J. Khan, D. Thurlby, Humma Shahid, D. Clayton, J. Yates, M. Bradley, A. Moore, A. Bird

Open Access
376 citations
Analysis v6

Related Content

Claims (6)

Assertion

People who smoke cigarettes have twice the risk of developing age-related macular degeneration due to oxidative damage and reduced blood flow to the retina.

Causal
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Assertion

People who stopped smoking more than 20 years ago have the same risk of developing advanced age-related macular degeneration as people who never smoked.

Correlational
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Assertion

People who have smoked more cigarettes over their lifetime, measured in pack-years, have a higher risk of developing advanced age-related macular degeneration than those with similar smoking duration but lower total exposure, and total tobacco dose is a stronger predictor than whether someone currently smokes, formerly smoked, or never smoked.

Correlational
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Assertion

People who have smoked more than 40 pack-years have 2.75 times higher odds of developing advanced age-related macular degeneration, including geographic atrophy and choroidal neovascularisation, compared to people who have never smoked.

Correlational
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Assertion

Non-smokers who breathe in secondhand smoke for five or more years are 87% more likely to develop end-stage age-related macular degeneration than non-smokers with no secondhand smoke exposure.

Correlational
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Assertion

People who smoke more than 40 pack-years have a higher risk of developing geographic atrophy than choroidal neovascularisation as a form of age-related macular degeneration.

Correlational
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