November 19, 2013

Insomnia: Risk Factor for Heart Attack, Depression, Osteoporosis and More

This is the fifth in a continuing series about sleep.

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A study that included over 24,000 Norwegian workers from 1995-1997 and again from 2006-2008 revealed that insomnia is a risk factor for heart attack, depression, osteoporosis, and other conditions. Results from the study – which tracked participants for over a decade – were reported on November 7 by Science Nordic and published in the Journal of Sleep Research.

Norwegian and Finnish researchers determined that insomnia sufferers are twice as likely to be diagnosed with depression as people who sleep well. The osteoporosis risk increase by 87% for insomniacs, and the risk from heart attack is 50% greater than it is among sound sleepers.

In addition, the research showed insomnia connections with anxiety, fibromyalgia, whiplash, rheumatoid arthritis, arthrosis (age-related cartilage deterioration) and asthma. While the team found connections between sleeplessness and obesity, hypertension and stroke, those links disappeared after the scientists adjusted for other factors.

Norwegian Institute of Public Health’s Børge Sivertsen, the study’s lead researcher, said: “The link to heart attacks is particularly interesting. One possible explanation is that sleep problems raise the stress response of the body, which has a negative impact on the function of the heart.”

Insomnia, Immune System, and Inflammation
The specific mechanisms that connect insomnia with these conditions aren’t clearly understood. But earlier studies link insomnia with changes in the immune system and a higher level of inflammation in the body, which renders insomniacs more vulnerable.

Interestingly, insomniacs did not show increased risk for obesity, type 2 diabetes or cancers.

Then there’s the issue of sleep apnea, which degrades sleep quality. Sufferers often stop breathing for up to 40 seconds several times during the night, and those disturbances strain the heart. The repeated “micro-awakenings” prevent sufferers from reaching deep sleep.

The study raises an important question: would successful treatment of insomnia remove increased risk factors for these dangerous diseases and conditions? In the study, researchers wrote:
We conclude that insomnia predicts cumulative incidence of several physical and mental conditions. These results may have important clinical implications, and whether or not treatment of insomnia would have a preventive value for both physical and mental conditions should be studied further.
Said Sivertsen: “If we can intervene at an early point and prevent and treat sleep problems, maybe we could cut down the development of anxiety and depression, or somatic health problems such as heart attacks.”

Insomnia Affects Work ... and Mortality
Sivertsen added that insomnia showed a predictably negative impact on job retention. Fatigue follows insomnia. Inactivity follows fatigue. Less exercise leads to more aches and pains, which keep people away from work. In addition, insomniacs are less productive at work, and are responsible for more accidents in the workplace.

While these new Scandinavian study results provide specific implications for insomniacs, we’ve known about the negative effects of poor sleep on health, generally.

A 2010 study -- published in the journal Sleep -- followed 1,741 men and women in central Pennsylvania for a decade or more. Doctors at Penn State’s Sleep Research and Treatment Center adjusted for age, race, education, body mass index, smoking, alcohol, depression, sleep disordered breathing, and sampling weight.

Results from that study are dramatic: Men who met the study’s definition for insomnia had a 21% increased mortality risk. Gender made a big difference: that risk for female insomniacs was 5%.

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