Macular Degeneration Twin Study – Vitamin D reduced, smoking increased (by 13X in later study)

Smoking, Dietary Betaine, Methionine, and Vitamin D in Monozygotic Twins with Discordant Macular Degeneration: Epigenetic Implications.

Ophthalmology. 2011 May 25. DOI: 10.1016/j.ophtha.2010.12.020
Seddon JM, Reynolds R, Shah HR, Rosner B.
Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, Massachusetts; Department of Ophthalmology, Tufts Medical Center, and Tufts University School of Medicine, Boston, Massachusetts.

OBJECTIVE: We evaluated monozygotic twin pairs with discordant age-related macular degeneration (AMD) phenotypes to assess differences in behavioral and nutritional factors.

DESIGN: Case series.

PARTICIPANTS: Caucasian male twin pairs from the United States Twin Study of Macular Degeneration.

METHODS: Twin pairs were genotyped to confirm monozygosity. Ocular characteristics were evaluated based on fundus photographs using the Wisconsin Grading System and a 5-grade Clinical Age-Related Maculopathy Staging System. We selected twin pairs discordant in each of the following phenotypic categories: Stage of AMD (n = 28), drusen area (n = 60), drusen size (n = 40), and increased pigment area (n = 56). The Wilcoxon signed-rank test and linear regression were used to assess associations between behavioral and nutritional characteristics and each phenotype within discordant twin pairs.

MAIN OUTCOME MEASURES: Differences in smoking and dietary factors within twin pairs discordant for stage of AMD, drusen area, drusen size, and pigment area.

RESULTS:
Representative fundus photographs depict the discordant phenotypes.
Pack-years of smoking were higher for the twin with the more advanced stage of AMD (P = 0.05).
Higher dietary intake of vitamin D was present in the twins with less severe AMD (P = 0.01) and smaller drusen size (P = 0.05) compared with co-twins, adjusted for smoking and age.
Dietary intakes of betaine and methionine were significantly higher in the twin with lower stage of AMD (P = 0.009) and smaller drusen area (P = 0.03), respectively.

CONCLUSIONS: The twin with the more advanced stage of AMD, larger drusen area, drusen size, and pigment area tended to be the heavier smoker.
The twin with the earlier stage of AMD, smaller drusen size and area, and less pigment tended to have higher dietary vitamin D, betaine, or methionine intake.
Results suggest that behavioral and nutritional factors associated with epigenetic mechanisms are involved in the etiology of AMD, in addition to genetic susceptibility.

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See also VitaminDWiki

• All items in category Vision and Vitamin D 112 items
• Vitamin D may help prevent macular degeneration in women less than 75 – April 2011
• Several Vision problems may be the result of vitamin D deficiency
• Vitamin D and Age-Related Macular Degeneration (and 2 AMD meta-analyses) – Oct 2017
• Smoking reduces vitamin D - many studies
• A smoker costs a company 5816 dollars every year – Aug 2013

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A few of the 66 publications which cited this study as of March 2019

• Vitamin D and Age-Related Macular Degeneration - Dissertation 2017
   Download the PDF from VitaminDWiki
• Associations Between Vitamin D Intake and Progression to Incident Advanced Age-Related Macular Degeneration - 2017 DOI:10.1167/iovs.17-21673
• Macular Degeneration Epidemiology: Nature-Nurture, Lifestyle Factors, Genetic Risk, and Gene-Environment Interactions – The Weisenfeld Award Lecture 2017
• Epigenetic Basis of Twin Discordance in Diseases: Future Benefits 2018
• Vitamin D and Age-Related Macular Degeneration 2017
• Incidence of and Risk Factors Associated With Age-Related Macular Degeneration: Four-Year Follow-up From the ALIENOR Study
  May 2018, doi: 10.1001/jamaophthalmol.2018.0504.
  13X higher risk of AMD if smoke 20 pack years (i.e. 2 packs a day for 10 years)
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