Racial/Ethnic Differences in Insomnia Trajectories Among U.S. Older Adults.

OBJECTIVES: Insomnia is reported to be more prevalent in minority racial/ethnic groups. Little is known, however, about racial/ethnic differences in changes in insomnia severity over time, particularly among older adults. We examined racial/ethnic differences in trajectories of insomnia severity among middle-aged and older adults.

DESIGN: Data were drawn from five waves of the Health and Retirement Study (2002-2010), a nationally representative longitudinal biennial survey of adults aged > 50 years.

SETTING: Population-based.

PARTICIPANTS: 22,252 participants from non-Hispanic white, non-Hispanic black, Hispanic, and other racial/ethnic groups.

MEASUREMENTS: Participants reported the severity of four insomnia symptoms; summed scores ranged from 4 (no insomnia) to 12 (severe insomnia). We assessed change in insomnia across the five waves as a function of race/ethnicity.

RESULTS: Across all participants, insomnia severity scores increased 0.19 points (95% CI: 0.14-0.24; t = 7.52; design df = 56; p < 0.001) over time after adjustment for sex, race/ethnicity, education, and baseline age. After adjusting for the number of accumulated health conditions and body mass index, this trend decreased substantially and even changed direction (B = -0.24; 95% CI: -0.29 to -0.19; t = -9.22; design df = 56; p < 0.001). The increasing trajectory was significantly more pronounced in Hispanics compared with non-Hispanic whites, even after adjustment for number of accumulated health conditions, body mass index, and number of depressive symptoms.

CONCLUSIONS: Although insomnia severity increases with age-largely due to the accumulation of health conditions-this trend appears more pronounced among Hispanic older adults than in non-Hispanic whites. Further research is needed to determine the reasons for a different insomnia trajectory among Hispanics.