Seasonal Variations in the Occurrence of Retinal Vein Occlusion: A Five-year Nationwide Population-based St

● PURPOSE: To determine whether seasonal variation
exists in the incidence of retinal vein occlusion.
● DESIGN: Retrospective, nationwide population-based
administrative database study.
● METHODS: We collected data on outpatient and emergency
visits for the period from January 1999 through
December 2003 from the Taiwan National Health Insurance
Research Database, a source that covers more
than 96% of Taiwan’s 23 million citizens. In total,
20,792 patients with a first-time diagnosis of either
central retinal vein occlusion or branch retinal vein
occlusion (The International Classification of Disease,
Ninth Revision, Clinical Modification [ICD-9-CM] code
362.35 or 362.36, respectively) were identified.
Monthly incidence of retinal vein occlusion was obtained
for each age group, each gender group, and for the entire
sample. The autoregressive integrated moving average
method of analysis was adopted to examine seasonality in
the monthly incidence of retinal vein occlusion.
● RESULTS: The monthly incidence rates of retinal vein
occlusion revealed significant seasonality, with a clear
peak in January for each age group and each gender
group, as well as for the total sample.
● CONCLUSIONS: Our study demonstrates significant seasonal
variations in the retinal vein occlusion incidence, with
the peak occurrence in the winter month of January.
(Am J Ophthalmol 2008;145:722–728. © 2008 by
Elsevier Inc. All rights reserved.)