New research shows that sleep disturbances have a strong negative impact on the immune system of people who have recently lost a spouse.
The overactivated immune system of the bereaved triggered by sleep disturbances — and resulting chronic inflammation — may make them more susceptible to heart disease or cancer, according to researchers from Northwestern and Rice universities.
Grieving spouses have a higher risk of developing heart disease or dying within a year of their loved one’s death, the researchers noted.
The study, known as Project Heart, compared recent widows or widowers with sleep disturbances such as insomnia to married or single individuals with sleep disturbances. The association between sleep disturbances and inflammation was two to three times higher in the grieving spouses, according to the study’s findings.
“We think these individuals are more vulnerable to the negative effects of poor sleep,” said corresponding author Dr. Diana Chirinos, a research assistant professor of preventive medicine at Northwestern University Feinberg School of Medicine.
“They have been hit twice. The death of a spouse is an acutely stressful event, and they have to adapt to living without the support of the spouse. Add sleep disturbance to their already stressful situation, and you double the stressor. As a result, their immune system is more overactivated.”
Chirinos conducted the study, published in Psychosomatic Medicine, when she was a researcher at Rice. It adds to previously published research showing individuals who have lost a spouse within the past three months have higher levels of pro-inflammatory cytokines — immune markers that indicate inflammation in the bloodstream — and lower heart rate variability, she said.
Both increase an individual’s risk for cardiac events, including death. Heart rate variability is the variation in time between each heartbeat, she explained.
“We already knew bereaved people had higher inflammation and a higher risk for heart disease and dying within a year of the spouse’s death,” said Chirinos. “But what was causing it? Was it the grief or sadness itself, loneliness, or sleep?
“Now we know it’s not the grief itself,” she continued. “It is the sleep disturbance that arises from that grief.”
The main sleep disturbance driving the overactivated immune system was poor sleep efficiency, which can include insomnia, early waking, or difficulty falling asleep.
The study controlled for other factors such as depression, obesity, and comorbid medical conditions, the researchers noted.
The overactive immune system was measured by the level of pro-inflammatory cytokines. These cells help fight disease in the short term, but long term are associated with the risk of developing heart disease and cancer.
The study looked at 101 individuals, with an average age 67. Half were identified through obituaries after they lost a spouse. The other half were the same age but were married or single.
One caveat of the study is that researchers used a measure of self-reported sleep, Chirinos said.
“We don’t know if an objective measure of sleep would have the same results,” she said.
The results show the importance of getting treatment for sleep problems for the bereaved, she added.
“Sleep problems may be most detrimental to health after losing a spouse,” Chirinos said. “If someone is experiencing sleep problems shortly after the loss of a spouse, it’s important for them to seek treatment.”
Source: Northwestern University