RISK-FACTORS FOR NUCLEAR OPALESCENCE IN A LONGITUDINAL-STUDY

This study evaluated risk factors for increases in nuclear opacificati on of the lens in the Longitudinal Study of Cataract (1989-1993; Bosto n, Massachusetts), which included 764 participants. Baseline data on d emographic, medical, and other risk factors were available from an ear lier case-control study; follow-up visits were completed yearly over a 4-year period. The lens photographs taken at baseline and at each fol low-up visit were graded using the Lens Opacities Classification Syste m III protocol. Analyses evaluated which risk factors collected at bas eline were related to increased nuclear opacification at follow-up. Th e MULCOX2 method, an extension of Cox regression for nested event-time data, was used to estimate the effects of the risk factors. This meth od accounted for the correlation between fellow eyes. Results showed t hat the risk of nuclear opacification increased with each year of age (relative risk (RR) = 1.07), white race (RR = 2.94), lower education ( RR = 1.50), use of gout medications (RR = 2.32), current smoking (RR = 1.58), family history of cataract (RR = 1.39), and preexisting poster ior subcapsular opacities (RR = 6.67). An association with early use o f eyeglasses was also suggested (RR = 1.37). In conclusion, nuclear op acification was related to demographic and other variables, including potentially modifiable factors such as current smoking and use of gout medications. Most risk factors identified by this longitudinal study confirm those found by the original case-control study. The increased risk of nuclear opacities in whites appears to be a new finding.