Abstract
Introduction::
In this study, we examined whether the relationship between visual impairment and depression is mediated by habitual sleep duration.
Methods::
In our analysis, we used data from the National Health Interview Survey conducted in 2005. The survey used a cross-sectional, multistage area probability design to acquire data from U.S. households. A total of 29,818 adults representative of the non-institutionalized U.S. population (mean age = 48 ± 18 yrs) participated in the study. Respondents answered questions during face-to-face interviews about chronic conditions. They also provided sociodemographic data, estimated habitual sleep duration, and rated depressed moods experienced in past 30 days (low scores represented greater depression).
Results::
Of the sample, 44% were men and 56% were women; Whites and Blacks represented 85% and 15%, respectively. At the time of the interview, 61% had a job. Overall, 35% indicated functional limitation due to chronic conditions: 28% reported hypertension; 8%, heart disease; 8%, cancer; 9%, diabetes; and 23%, arthritis. Ten percent reported visual impairment even with glasses or lens. The average respondent slept 7 hrs habitually. Fisher’s Exact test indicated visually impaired individuals were more likely to report short (≤5 hrs) or long (≥9 hrs) sleep duration [28% vs. 16%; Χ2=258, p<0.0001] than their counterparts. ANOVA results indicated that they were more depressed [18 ± 3 vs. 16 ± 4; F=1239, p<0.0001]. However, effects of visual impairment on depression were dependent on habitual sleep duration [F=27, p<0.0001]; individuals reporting both visual impairment and short/long sleep tended to be more depressed. The model adjusted for age, sex, and race effects on depression.Discussion:Individuals with visual impairment experience more depression and are characterized by a higher prevalence of short and long sleep. Depression is worse among respondents who reported visual impairment and sleeping unusually less or more than the population mode.
Keywords: vision and action • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • quality of life