HealthDay News — Half of older adults sleep with some light on, which was significantly associated with cardiovascular risk factors, according to a study published online June 22 in SLEEP.
Minjee Kim, M.D., from the Northwestern University Feinberg School of Medicine in Chicago, and colleagues examined associations between light at night and cardiovascular risk factors among 552 community-dwelling older adults (aged 63 to 84 years) with seven-day actigraphy recording for activity and light measures.
The researchers found that fewer than half of the study participants consistently had a five-hour period of complete darkness per day. Further, exposure to light at night was associated with a higher prevalence of obesity (multivariable-adjusted odds ratio, 1.82), diabetes (odds ratio, 2.00), and hypertension (odds ratio, 1.74). Associations were also seen for light at night and (1) later timing of lowest light exposure and lowest activity, (2) lower interdaily stability and amplitude of light exposure and activity, and (3) higher wake after sleep onset.
“It will be important for future prospective population studies to include examination of light exposure patterns in young-to-middle-aged adults as a potential modifiable risk factor for cardiovascular diseases and negative health outcomes,” the authors write. “Furthermore, intervention trials will be needed to elucidate how different components of light at night, such as timing, duration, frequency, and chronicity of exposure and intensity and wavelength of light, impact human health.”