Risk factors for retinal detachment

We recently reported a case-control study1 testing the hypothesis that heavy occupational lifting or manual handling (requiring the Valsalva maneuver) may be a risk factor for retinal detachment among people who are myopic (nearsighted). This study also suggested a possible role for obesity. To evaluate the study hypothesis, we had restricted our analysis to myopic subjects, adjusting for degree of myopia. Other etiologic studies of retinal detachment,2,3 although not restricted to myopic subjects, have provided little information on risk factors among nonmyopic people. We therefore did a supplementary analysis of our data to explore how risk factors for retinal detachment vary in nonmyopic subjects compared with near-sighted people. In the absence of data for suitable nonmyopic control subjects, we conducted a case-case analysis of all the myopic cases of retinal detachment included in the parent study1 (26 women, 35 men), alongside the previously excluded nonmyopic cases (29 women, 30 men). We analyzed risk factors such as heavy lifting/manual handling, body mass index (BMI), and alcohol consumption, along with age, head/eye trauma, and eye surgery. Occupational lifting of at least 10 kg (commonly requiring the Valsalva maneuver) was again evaluated by a cumulative lifting index, calculated as the product of load (kg), frequency (number of lifting maneuvers/ wk), and number of years of lifting (using the same cut-offs: heavy lifting, 8000 kg frequency year; reference category, no lifting).1 For multivariate analysis, we used ordered logistic regression analysis to take into account severity of myopia (mild/moderate/ severe), additionally adjusting for sex. Perhaps unsurprisingly, there was no sign of any association for either eye surgery or head trauma retinal detachment (Table). The point estimates close to unity suggest that the effects of these 2 major predisposing factors on retinal detachment4 are similar in nonmyopic and myopic people. The more pronounced age-related risk in nonmyopic cases (4-fold after 65 years) can be attributed to the impact of near-sightedness as a predisposing factor for retinal detachment across the age spectrum. Regarding heavy lifting/manual handling, the absence of any clear association (between nonmyopic and myopic cases) with retinal detachment leads us to hypothesize that this factor may increase the risk of retinal detachment regardless of myopia. As for BMI, there were signs of a possible dose-response relation, suggesting that obesity might conceivably be an even more prominent risk factor for retinal detachment among nonmyopic people. Perhaps the most intriguing finding relates to alcohol consumption: heavy drinking appeared to be associated with a roughly 4-fold higher risk of retinal detachment in nonmyopic cases compared with myopic cases. Notably, there were signs of a dose-response relation through light to moderate to heavy drinking (and, considering the nondrinkers, perhaps also of the J-shaped curve often observed in etiologic studies of cardiovascular diseases 5). Available data regarding the possible role of heavy drinking as a risk factor for eye diseases are contradictory. 6 Our observations suggest that the plausible etiologic role of heavy drinking in retinal detachment might be more relevant (or more evident) in nonmyopic people, and underline the need6 for clarification of the effect of heavy drinking on this and other eye conditions. These results may provide useful hints for future hypothesis-driven research into plausible risk factors for retinal detachment, including high alcohol intake, heavy lifting, and obesity. They also highlight the need for analytic studies to evaluate risk factors separately for nonmyopic people— especially because retinal detachment often occurs in the absence of myopia.