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  • Cadmium Exposure Increases Risk of Contrast Sensitivity Impairment

    By Lynda Seminara
    Selected and Reviewed By: Neil M. Bressler, MD, and Deputy Editors
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    Journal Highlights

    JAMA Ophthalmology, December 2018

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    Paulsen et al. set out to determine the incidence of and factors associated with deficits in contrast sensitivity (CS). They found that CS impairment was linked to smoking and blood levels of cadmium, but not to lead levels.

    For this study, the authors included patients from the Beaver Dam Offspring Study who had normal CS in both eyes at baseline. Participants were between the ages of 21 and 84, and baseline data were gathered from June 2005 through early August 2008. Two follow-up exams occurred subsequently at five-year intervals. CS testing was assessed with Pelli-Robson letter sensitivity charts. Incident impairment was defined as a log CS score <1.55 in either eye at a follow-up exam. Levels of cadmium and lead were measured in whole blood by using inductively coupled plasma mass spectrometry. Associations be­tween baseline characteristics and CS impairment were evaluated using Cox proportional hazard models and were expressed as hazard ratios (HR) and 95% confidence intervals (CI).

    The mean age of participants (N = 1,983) was 48 years; 52% were female. The 10-year cumulative incidence of CS impairment was 24.8% (95% CI, 22.9-26.8) and was similar for men (24.6%) and women (24.9%). It was highest (66.3%) in the oldest participants (65-84 years). Factors linked to greater risk of CS impairment were cadmium level in the highest quintile (HR, 1.35; 95% CI, 1.02-1.78), older age (HR, 1.36; 95% CI, 1.25-1.47), and plaque sites (four to six sites: HR, 2.75; 95% CI, 1.26-6.05; one to three sites: HR, 1.43; 95% CI, 1.07-1.92). Other contributors were impaired visual acuity (HR, 3.61; 95% CI, 1.61-8.10), cataract (HR, 1.99; 95% CI, 1.21-3.28), and larger waist circumference (HR, 1.06; 95% CI, 1.01-1.11). Factors denoting lower risk were male sex (HR, 0.77; 95% CI, 0.60-0.98) and any alcohol consumption in the last year (HR, 0.61; 95% CI, 0.43-0.88). When cadmium exposure was replaced with smoking status in these models, the findings were similar. Lead level did not affect risk.

    Many of the identified risk factors are modifiable, which may imply that changes in lifestyle could reduce the risk of CS impairment. Weight loss and efforts to improve vascular health also may be beneficial. (Also see related commentary by Xiang Li, PhD, in the same issue.)

    The original article can be found here.