Vision Impairment and Subjective Cognitive Decline–Related Functional Limitations — United States, 2015–2017

Sharon Saydah, PhD; Robert B. Gerzoff, MS; Christopher A. Taylor, PhD; Joshua R. Ehrlich, MD; Jinan Saaddine, MD, PhD

Disclosures

Morbidity and Mortality Weekly Report. 2019;68(20):453-457. 

In This Article

Abstract and Introduction

Introduction

Vision impairment affects approximately 3.22 million persons in the United States and is associated with social isolation, disability, and decreased quality of life.[1] Cognitive decline is more common in adults with vision impairment.[2,3] Subjective cognitive decline (SCD), which is the self-reported experience of worsening or more frequent confusion or memory loss within the past 12 months, affects 11.2% of adults aged ≥45 years in the United States.[4] One consequence of SCD is the occurrence of functional limitations, especially those related to usual daily activities; however, it is not known whether persons with vision impairment are more likely to have functional limitations related to SCD.[4] This report describes the association of vision impairment and SCD-related functional limitations using Behavioral Risk Factor Surveillance System (BRFSS) surveys for the years 2015–2017. Adjusting for age group, sex, race/ethnicity, education level, health insurance, and smoking status, 18% of adults aged ≥45 years who reported vision impairment also reported SCD-related functional limitations, compared with only 4% of those without vision impairment. Preventing, reducing, and correcting vision impairments might lead to a decrease in SCD-related functional limitations among adults in the United States.

This analysis used data from the BRFSS, an annual state-based, cross-sectional telephone survey of noninstitutionalized adults aged ≥18 years, combining data from 2015, 2016, and 2017.* During those 3 years, 208,601 respondents aged ≥45 years in 49 states (all except Pennsylvania), Puerto Rico, and the District of Columbia (DC) completed the optional cognitive decline module.†,§,¶ For states that administered the module in multiple years, only the most recent year's data were included. For the BRFSS surveys in 2015, 2016, and 2017, the combined landline and cellular telephone response rates among states, Puerto Rico, and DC ranged from 30.6% to 64.1% (median = 45.7%).

Among all respondents aged ≥45 years, those classified as having SCD responded affirmatively to the question "During the past 12 months, have you experienced confusion or memory loss that is happening more often or is getting worse?" Respondents with SCD were then asked two follow-up questions: 1) "During the past 12 months, as a result of confusion or memory loss, how often have you given up day-to-day household activities or chores you used to do, such as cooking, cleaning, taking medications, driving, or paying bills?" and 2) "During the past 12 months, how often has confusion or memory loss interfered with your ability to work, volunteer, or engage in social activities outside the home?" Responses of "always," "usually," and "sometimes" were classified as positive responses, and responses of "rarely" and "never" were classified as negative responses.[4] Functional limitations caused by SCD were defined as a positive response to either of the two follow-up questions. Vision impairment was defined as a yes response to the question "Are you blind or do you have serious difficulty seeing, even when wearing glasses?" Descriptive analyses examined population characteristics by vision impairment and SCD-related functional limitations status. Covariates included age group (45–64 years, 65–74 years, or ≥75 years); sex (male or female); race/ethnicity (non-Hispanic white, non-Hispanic black, non-Hispanic multiracial, Hispanic, or non-Hispanic other); education level (less than high school, high school graduate or some college, or college graduate); smoking status (never, former, or current); and having health insurance (yes or no). Multivariate logistic regression models were used to calculate predicted marginal proportions and examine the relationship between vision impairment and SCD-related functional limitations, adjusting for age, sex, race/ethnicity, education level, and smoking status. All estimates used the BRFSS-provided sampling weights to account for the complex survey design and nonresponse. Analysis was completed using SUDAAN (version 11.0.3; RTI International).

The overall prevalence of vision impairment among respondents was 6.2% (95% confidence interval [CI] = 6.0%–6.3%), and the overall prevalence of SCD with functional limitations was 5.5% (95% CI = 5.3%–5.7%). The prevalence of vision impairment without functional limitations related to SCD increased with age from 4.4% (95% CI = 4.2%–4.7%) among those aged 45–64 years to 7.2% (95% CI = 6.7%–7.6%) for those aged ≥75 years (Table). Among adults reporting SCD-related functional limitations without vision impairment, the proportion in each of the three age groups was similar (range = 2.8 [65–74 years] to 4.4 [45–64 years]), as was the age distribution among those with vision impairment (range = 0.9% [age 65–74 years] to 1.8 [45–64 years]). Similarly, no significant differences in report of SCD-related functional limitations among those with and without vision impairment were seen when stratified by race/ethnicity. Vision impairment without SCD related limitations was highest among Hispanics (10.4%, 95% CI = 9.3–11.6) and lowest among non-Hispanic whites (3.6%, 95% CI = 3.5%–3.8%). However, prevalences of vision impairment and SCD-related functional limitations were higher among adults with less than a high school diploma (4.1%, 95% CI = 3.6%–4.6%), who were current smokers (3.6%, 95% = 3.2%–4.0%), and who did not have health insurance (3.0%, 95% CI = 2.5%–3.7%) than among college graduates (0.4%, 95% CI = 0.3%–0.4%), those who had never smoked (0.9%, 95% CI = 0.8%–1.1%), and those who had health insurance (1.4%, 95% CI =1.3%–1.5%).

After adjusting for demographics, smoking status, and vision impairment, the prevalence of functional limitations related to SCD was highest among persons aged 45–64 years (6%) and lowest among those aged 65–74 years (4%; p<0.001) (Figure). In addition, non-Hispanic whites and Hispanics reported the lowest prevalences (5%), and non-Hispanic persons of other races reported the highest prevalence (8%) (p<0.001). The prevalence of SCD-related functional limitations among persons having less than a high school education (9%) was three times that of those reporting being a college graduate (3%) (p<0.001). Being a current smoker was associated with a higher prevalence of SCD-related functional limitations (9%), compared with being a former smoker (5%) or a person who had never smoked (4%) (p<0.001). After adjusting for demographics and smoking status, the highest prevalence of SCD-related functional limitations (18%) was among adults with vision impairment; prevalence among those with no reported vision impairment was 4% (p<0.001).

Figure.

Adjusted percentage* of subjective cognitive decline (SCD)–related functional limitations among adults aged ≥45 years, by demographic characteristics, smoking status, and vision impairment — Behavioral Risk Factor Surveillance System, 49 states, Puerto Rico, and the District of Columbia, 2015–2017
Abbreviation: HS = high school.
* Adjusted prevalence based on predicted marginal from logistic regression models adjusting for age, sex, race/ethnicity, smoking status, health insurance status, and vision impairment.
Excluding Pennsylvania.

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