Researchers say exposure to cadmium (but not lead) and smoking have been associated with increased risk for contrast sensitivity (CS) impairment in the 10-year follow-up period in a cohort of middle-aged adults.

In the study published in Jama Ophthalmology, the authors suggest reducing exposure to cadmium, smoking, or both may reduce the burden of contrast sensitivity impairment in middle-aged adults.

The Beaver Dam Offspring Study is an ongoing longitudinal cohort study of aging involving adults in Beaver Dam, Wisconsin. 1983 participants who were free of CS impairment in both eyes at baseline were included, and baseline data was collected from 2005, through 2008, when the participants ranged from 21 to 84 years of age. Two follow-up examinations occurred at 5-year intervals.

Of the 1983 participants included, 1028 (51.8%) were female and 955 (48.2%) were male, with a mean (SD) age of 48 (9.3) years. The 10-year cumulative incidence of CS impairment was 24.8% (95% CI, 22.9-26.8), similar in women (24.9%) and men (24.6%), and highest in the oldest age group (65-84 years) at 66.3%. In multivariable models, 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), larger waist circumference (HR, 1.06; 95% CI, 1.01-1.11), and more plaque sites (1-3 sites: HR, 1.43; 95% CI, 1.07-1.92; 4-6 sites: HR, 2.75; 95% CI, 1.26-6.05) were among the factors associated with increased risk, while male sex (HR, 0.77; 95% CI, 0.60-0.98) and any alcohol consumption (HR, 0.61; 95% CI, 0.43-0.88) were associated with decreased risk. Results were similar when smoking status replaced cadmium exposure in the models. Lead level was not associated with increased risk.

This study’s findings appear to imply that changes in behavior may reduce future incidence of CS impairment.