Association of Cadmium and Lead Exposure With the Incidence of Contrast Sensitivity Impairment Among Middle-aged Adults

Abstract

Importance Contrast sensitivity (CS) is an important indicator of visual function that impacts daily life, including mobility, visually intensive tasks, safety, and autonomy. Understanding risk factors for CS impairment could lead to prevention of decreases in visual function. Objective Determine the incidence of CS impairment in a large cohort, and investigate factors potentially associated with incidence, including cadmium (Cd) and lead (Pb) levels. Design The Beaver Dam Offspring Study (BOSS, baseline 2005–2008) was conducted in the adult children of the participants of the population-based Epidemiology of Hearing Loss Study. Follow-up examinations occurred in 2010–2013 and 2015–2017. Setting Longitudinal cohort study Participants 1983 participants free of CS impairment at baseline. Particpants were primarily non-hispanic white, 51.8% women, mean age 48 years (standard deviation=9.3). Main Outcome CS was measured using Pelli-Robson Letter Sensitivity Charts, and incident impairment was defined as a log CS score less than 1.55 in either eye at any follow-up examination. Cd and Pb levels were measured in whole blood, using inductively coupled plasma mass spectrometry. Associations between baseline characteristics and CS impairment incidence were examined using Cox proportional hazard models and quantified as hazard ratios (HR) with 95% confidence intervals (CI). Results The 10-year cumulative incidence of CS impairment was 24.8%, was similar in women and men, and was highest in the oldest age group (64–84 years) at 66.3%. In multivariable models, a Cd level in the highest quintile (Q5 vs. Q1–4) (HR=1.35, CI=1.02, 1.78), age (per 5 years) (HR=1.34, CI=1.25,1.44), waist circumference (per 5 cm) (HR=1.06, CI=1.02,1.10), and number of plaque sites (1–3 vs. 0, HR=1.37, CI=1.03,1.81; 4–6 vs. 0, HR=2.63, CI=1.26,5.48) were associated with increased risk, while male sex (HR=0.77, CI=0.60,0.98) and any alcohol consumption (vs. none, HR=0.54, CI=0.39, 0.76) were associated with decreased risk. Results were similar when smoking status replaced Cd in the models. Lead level was not associated with increased risk. Conclusions and Relevance Incident CS impairment was common in the 10-year follow-up. Cd, but not Pb, was associated with increased risk. Other modifiable risk factors were associated with risk implying that changes in behavior could reduce future incident impairment.

Sensorineural Impairments, Cardiovascular Risk Factors, and 10-Year Incidence of Cognitive Impairment and Decline in Midlife: The Beaver Dam Offspring Study

“…Data were collected as part of the BOSS (2004-present), a longitudinal study of sensory health and aging in the adult offspring of participants in the population-based EHLS (1993-present) (8,21,25). The baseline BOSS data collection phase occurred during 2005-2008 (N = 3,298 [66.3%]) with follow-ups at 5 (2010)(2011)(2012); N = 2,792 [85%]) and 10 years (2015-2017; N = 2,405 [73%]) (23,24). Participants with a Mini-Mental State Examination (MMSE) score less than 24 or report of Alzheimer's disease (AD) or dementia at baseline (n = 9 [0.3%]), or missing baseline MMSE (n = 239 [7.3%]), or follow-up cognitive test data (n = 494 [15%]) were excluded from the present study resulting in data from 2,556 participants available for the analyses of 10-year cognitive decline and impairment.…”

“…Olfaction was measured using the San Diego Odor Identification Test, and impairment was defined as identifying less than six of eight odorants correctly (8,25). Contrast sensitivity was measured in each eye separately using Pelli-Robson letter charts, and visual impairment was defined as contrast sensitivity of less than 1.55 log units in the better eye (24,29) (see Supplementary Methods).…”

“…As with CVRF/CVD, sensorineural impairments in midlife may be important predictors of concurrent and future cognitive health, but longitudinal studies that include multiple sensorineural measures in middle-aged adults are lacking. Because CVRF/CVD have been associated with the development of both sensorineural (20)(21)(22)(23)(24) and cognitive dysfunction (13)(14)(15)(16)(17)19), it is important to evaluate both sensorineural and CVRF/CVD in studies investigating predictors of cognitive decline or impairment. The purpose of the present study was to evaluate the longitudinal associations of sensorineural impairments and CVRF/CVD with impairment and declines in cognitive function over 10 years in a primarily middle-aged cohort.…”

The Association of Psychological Well-Being With Sensory and Cognitive Function and Neuronal Health in Aging Adults

“…We used the last triplet in which a participant correctly identified at least two of the 3 letters to assign a log CS score. Impairment was defined as log CS score ≤ 1.55 (Paulsen et al, 2018). We measured best-corrected monocular visual acuity (VA) in each eye with the Early Treatment Diabetic Retinopathy Study chart R modified for a 2 m distance (ETDRS Coordinating Center Department of Epidemiology and Preventive Medicine University of Maryland School of Medicine, 1980; Paulsen et al, 2018).…”

“…Impairment was defined as log CS score ≤ 1.55 (Paulsen et al, 2018). We measured best-corrected monocular visual acuity (VA) in each eye with the Early Treatment Diabetic Retinopathy Study chart R modified for a 2 m distance (ETDRS Coordinating Center Department of Epidemiology and Preventive Medicine University of Maryland School of Medicine, 1980; Paulsen et al, 2018). We asked participants to read the letters from the 2 m chart until they could no longer correctly identify at least three of 5 letters on a line (scores 0–70).…”