Occupational cataracts and lens opacities in interventional cardiology (O'CLOC study): are X-Rays involved?

Abstract

BackgroundThe eye is well known to be sensitive to clearly high doses (>2 Gy) of ionizing radiation. In recent years, however, cataracts have been observed in populations exposed to lower doses. Interventional cardiologists are repeatedly and acutely exposed to scattered ionizing radiation (X-rays) during the diagnostic and therapeutic procedures they perform. These "low" exposures may cause damage to the lens of the eye and induce early cataracts, known as radiation-induced cataracts. The O'CLOC study (Occupational Cataracts and Lens Opacities in interventional Cardiology) was designed to test the hypothesis that interventional cardiologists, compared with an unexposed reference group of non-interventional cardiologists, have an increased risk of cataracts.Method/DesignThe O'CLOC study is a cross-sectional study that will include a total of 300 cardiologists aged at least 40 years: one group of exposed interventional cardiologists and another of non-interventional cardiologists. The groups will be matched for age and sex. Individual information, including risk factors for cataracts (age, diabetes, myopia, etc.), will be collected during a telephone interview. A specific section of the questionnaire for the exposed group focuses on occupational history, including a description of the procedures (type, frequency, radiation protection tool) used. These data will be used to classify subjects into "exposure level" groups according to cumulative dose estimates. Eye examinations for all participants will be performed to detect cataracts, even in the early stages (lens opacities, according to LOCS III, the international standard classification). The analysis will provide an estimation of the cataract risk in interventional cardiology compared with the unexposed reference group, while taking other risk factors into account. An analysis comparing the risks according to level of exposure is also planned.DiscussionThis epidemiological study will provide further evidence about the potential risk of radiation-induced cataracts at low doses and contribute to cardiologists' awareness of the importance of radiation protection.Trial RegistrationNCT01061463

Ionizing Radiation as a Risk Factor for Cataract: What about Low-Dose Effects?

“…In Worgul et al [12], uncertainties on the estimated doses remain an important limit of the paper, even if the impact of dose uncertainty on the results was assessed. In medical staff studies, doses were either based on passive dosimetry (chest badge) [28] which may not be a good index for eye lens exposure, especially when radiation protection eyewear is used, or based on description of workload in terms of procedures and mean doses per procedure, which may suffer from memory bias [29][30][31]. However, radiation-induced cataracts have been globally observed in different exposed populations at lower doses (< 1 Gy) than the expected dose threshold of 2 Gy.…”

“…In France, the multicenter cross-sectional O'CLOC study (Occupational Cataracts and Lens Opacities in interventional Cardiology) was performed between October 2009 and April 2011 [31]. 106 interventional cardiologists and 99 unexposed workers were included.…”

Radiation Protection from the Point of View of Patients of the Radiology Department at the University Clinical Hospital in Białystok

“…W literaturze przedmiotu zwraca się uwagę, że w badaniach prowadzonych w Skandynawii i Francji stwierdzono korelację między występowaniem zaćmy a pracą związaną z narażeniem na promieniowanie jonizujące [28][29][30]. Badania amerykań-skie Doody et al dotyczące ryzyka wystąpienia raka piersi u kobiet zatrudnionych w placówkach, gdzie istnieje ryzyko narażenia na promieniowanie, wykazały, że rak piersi jest skorelowany z okresem zatrudnienia [31].…”

Use of personal radiation protection tools and individual dosimetric monitoring in a sample of interventional cardiologists in France, 2005–2009

“…The aim of the O'CLOC study was to analyse the risk of radiation-induced cataracts among ICs (Jacob et al, 2010). As part of this study, we developed a specific questionnaire to collect information about lifetime occupational activity, intended to obtain as complete and precise a picture as possible of the workload of ICs as well as their use of radiation protection equipment, including lead aprons, in particular, but also lead thyroid shields, lead eyewear and face shields, and ceilingsuspended shields in every centre where they had worked or were working.…”

“…Before we began the O'CLOC epidemiological study (Occupational Cataracts and Lens Opacities in Interventional Cardiology) (Jacob et al, 2010), little was known about radiation protection among ICs in France. In this paper, we use a sample of French ICs from that study (Jacob et al, 2010) to describe selfreported use of individual dosimeter and radiation protection tools by these specialists, but also information of dosimetric monitoring registered in the SISERI (Système d'Information de la Surveillance de l'Exposition aux Rayonnement Ionisants, that is, an information system for monitoring exposure to ionising radiation) database, to obtain an overview of radiation protection as it was actually practised by ICs from 01/01/2005 to 31/12/2009.…”