Abstract
Purpose: :
Functional impairment (FnI) in activities of daily living (ADLs) is associated with adverse outcomes such as falls and nursing home placement. We estimated the prevalences of FnI and vision-related (VR) FnI and assessed their association with race/ethnicity in the U.S. population aged 50+ years.
Methods: :
The National Health and Nutrition Examination Survey (NHANES) is a representative survey of the US population. In 1999-06, NHANES participants were interviewed and examined, including measurement of presenting visual acuity (PVA) by autorefractor. Participants reported their degree of difficulty for 20 ADLs (mobility, strength, self-care) and 6 VR ADLs. Responses of "extreme difficulty" or "unable to do" for an item were counted as impairment. Summary measures VR-FnI and FnI were defined as impairment on any of the 6 VR-ADLs or 20 ADLs, respectively. Participants with a history of any of 13 conditions (cardiovascular disease, diabetes, etc) were counted as having comorbidity (CMO).
Results: :
9707 participants age 50+ were interviewed; 7789 had complete information on PVA, FnI, and VR-FnI. 54% were female, 7% had PVA ≤20/50 in the better-seeing eye, 17% had no CMO, 35% had no private health insurance, and 24% had <high school education. The prevalence of VR-FnI was 9.4% (95% confidence interval (CI), 8.5-10.2%). Compared with non-Hispanic Whites, after adjustment for age, the odds ratio (OR) for VR-FnI was 2.47 (95% CI, 1.93-3.16) for non-Hispanic Blacks and 2.68 (95% CI, 2.10-3.44) for Mexican-Americans. Further adjustment for PVA, CMO, gender, private health insurance, and FnI reduced ORs to 1.96 (1.45-2.64) and 2.02 (1.43-2.85), respectively. The prevalence of FnI was 28.1% (95% CI, 27.5-30.6%). Compared with non-Hispanic Whites, after adjustment for age, the OR for FnI was 1.51 (95% CI, 1.28-1.78) for non-Hispanic Blacks and 1.26 (95% CI, 1.02-1.54) for Mexican-Americans. Further adjustment for PVA, CMO, gender, private health insurance, and VR-FnI reduced ORs to 1.06 (0.87-1.28) and 0.82 (0.65-1.04), respectively.
Conclusions: :
FnI was reported significantly more often by non-Hispanic Blacks and Mexican-Americans than by non-Hispanic Whites, but this race/ethnicity difference did not persist after adjustment for potentially confounding factors (demographics, health status, PVA). In contrast, VR-FnI was reported significantly more often by non-Hispanic Blacks and Mexican-Americans than by non-Hispanic Whites, even after adjustment for potentially confounding factors. Reasons for this finding may include cultural differences in reporting VR-FnI, different expectations for VR-functioning, or residual confounding.