Sleep problems, depressive symptoms precede onset of certain illnesses
Sleep problems and depressive symptoms, and a combination of both, are differentially associated with the future incidence of physical illness, according to a study.
Researchers followed 7,395 participants (mean age 65.81 years; 54.8 percent female) from the English Longitudinal Study of Ageing (ELSA) for 6 years. Sleep and depressive symptoms were measured using an adapted version of the Jenkins Sleep Problems questionnaire and the Centre for Epidemiological Studies Depression scale, respectively.
Multivariable logistic regression models showed that depressive symptoms predicted incident coronary heart disease (odds ratio [OR], 1.11; 95 percent CI, 1.04–1.20; p=0.004) and diabetes/high blood glucose (OR, 1.13; 1.04–1.22; p=0.002) independent of sleep problems.
Depressive symptoms and sleep problems both predicted incident arthritis (OR, 1.10; 1.04–1.16; p=0.002 and OR, 1.14; 1.02–1.26; p=0.019).
Finally, the presence of both elevated depressive symptoms and elevated sleep problems increased the likelihood of developing cancer by 67 percent (OR, 1.67; 1.17–2.39; p=0.004) relative to low depressive symptoms/low sleep problems.
Possible mechanisms underlying the link between sleep and disease onset involve the neuroendocrine system and cortisol. Specifically, changes to the neuroendocrine system have been observed after sleep loss, and depression has long been implicated in increased cortisol expression. Modulation of cortisol responses may be pertinent to inflammatory diseases such as coronary heart disease and arthritis, as cortisol is known to be involved in regulation of the immune system. [Sleep Med Rev 2008;12:197-210; Prog Neuropsychopharmacol Biol Psychiatry 2011;35:722-729]
Although more work is needed to determine the exact pathways by which sleep and depression operate to affect future disease onset, the present data suggest that sleep problems and depressive symptoms precede the onset of physical illness, researchers said.