Differentiating nonrestorative sleep from nocturnal insomnia symptoms: demographic, clinical, inflammatory, and functional correlates

Increased insomnia symptoms predict the onset of back pain among employed adults

Background

Back pain is among the most prevalent pain disorders causing chronic disability among adults, and insomnia is a common co-morbidity. However, whether insomnia precedes back pain or vice versa remains unclear. The current study tested the temporal association between insomnia and back pain.

Methods

A longitudinal design was used to investigate whether changes in insomnia over time predict the onset of back pain and vice versa. The study was conducted on a cohort of active healthy working adults (N = 2,131, 34% women) at three time points (T1, T2, and T3) over a period of 3.7 years (range = 2.2–5.12) years. Logistic regression analysis was used to test whether increased insomnia symptoms from T1 to T2 predicted the onset of new back pain. Ordinary least squares regression was used to test whether the existence of back pain at T2 predicted an increase in insomnia from T2 to T3.

Results

The results indicated that after controlling for socioeconomic variables, self-reported health, lifestyle behaviors, and anthropometrics, a T1–T2 increase in insomnia symptoms was associated with a 1.40-fold increased risk of back pain at T3 (OR = 1.40; 95% CI = 1.10–1.71). No support was found for reverse causation; i.e., that back pain predicts subsequent increase in insomnia.

Conclusions

Insomnia appears to be a risk factor in the development of back pain in healthy individuals. However, no evidence of reverse causation was found.

Why sleep is important for health: a psychoneuroimmunology perspective

Sleep has a critical role in promoting health. Research over the past decade has documented that sleep disturbance has a powerful influence on the risk of infectious disease, the occurrence and progression of several major medical illnesses including cardiovascular disease and cancer, and the incidence of depression. Increasingly, the field has focused on identifying the biological mechanisms underlying these effects. This review highlights the impact of sleep on adaptive and innate immunity, with consideration of the dynamics of sleep disturbance, sleep restriction, and insomnia on (a) antiviral immune responses with consequences for vaccine responses and infectious disease risk and (b) proinflammatory immune responses with implications for cardiovascular disease, cancer, and depression. This review also discusses the neuroendocrine and autonomic neural underpinnings linking sleep disturbance and immunity and the reciprocal links between sleep and inflammatory biology. Finally, interventions are discussed as effective strategies to improve sleep, and potential opportunities are identified to promote sleep health for therapeutic control of chronic infectious, inflammatory, and neuropsychiatric diseases.

Sleep-wake cycle in young and older persons with a lifetime history of mood disorders

Considering the marked changes in sleep and circadian rhythms across the lifespan, age may contribute to the heterogeneity in sleep-wake profiles linked to mood disorders. This study aimed to investigate the contributions of age and depression severity to sleep-wake disturbances. The Hamilton Depression Rating Scale (HDRS) was administered to assess current symptoms severity in 238 persons with a history of a mood disorder between 12 and 90 years of age (y.o.). Actigraphy was recorded over five to 22 days. Regression analyses and analyses of variance [age (12–19 y.o., 20–39 y.o., 40–59 y.o., and ≥60 y.o.) by depression severity (HDRS< and ≥8)] were conducted. The 12–19 y.o. and 20–39 y.o. groups had a delayed sleep schedule and acrophase compared to all other groups. The ≥60 y.o. group had a lower rhythmicity and amplitude (p≤.006) than the 12–19 y.o. group (p≤.046). Participants with a HDRS≥8 spent longer time in bed, had later sleep offset times and had lower circadian rhythmicity than those with a HDRS<8 (p≤.036). Younger age and higher HDRS score correlated with later sleep onset and offset times, longer time in bed, higher WASO, lower sleep efficiency and later acrophase (p≤.023). Age was a significant predictor of delayed sleep and activity schedules (p≤.001). The profile of sleep-wake cycle disturbances associated with mood disorders changes with age, with prominent sleep phase delay during youth and reduced circadian strength in older persons. Conversely, disruptions in sleep consolidation seem more stable across age.