As if you didn't have enough to worry about during those sleepless nights, a Norwegian study out Monday suggests that people with insomnia face a 27 to 45 percent higher risk of heart attack.
About one-third of people report having trouble sleeping and should see a doctor for help, urged the authors of the study published in Circulation, a journal of the American Heart Association.
"Sleep problems are common and fairly easy to treat," said Lars Erik Laugsand, lead researcher from the Norwegian University of Science and Technology Department of Public Health in Trondheim.
"So it's important that people are aware of this connection between insomnia and heart attack and talk to their doctor if they're having symptoms."
The data came from 52,610 Norwegian adults who answered a national survey about their insomnia symptoms in 1995-97.
Over the next 11 years, researchers identified 2,368 people who had their first heart attacks, via hospital records and Norway's National Cause of Death Registry.
After adjusting for factors such as age, sex, marital status, education level, blood pressure, cholesterol, diabetes, weight, exercise, shift work, depression and anxiety, researchers found the highest boost in risk among the most troubled sleepers.
When they compared data from people who said they usually slept fine to people who said they had trouble falling asleep almost daily over the course of the last month, they saw a 45 percent higher risk in the sleepless group.
Those who said they could fall asleep but not stay asleep all night showed a 30 percent higher risk of heart attack than the group that slept well.
And those who said they did not wake up feeling refreshed showed a 27 percent higher risk.
The researchers did not adjust their data for obstructive sleep apnea, a condition that arises when air flow is interrupted during sleep, and cautioned that particular sleep patterns among the Norwegian sample may not make the data immediately applicable to other populations.
However, similar links between insomnia and cardiovascular disease have been suggested in previous studies on US populations.
"It is becoming increasingly evident that insomnia is a significant modifiable risk factor for cardiovascular disease," said Girardin Jean-Louis, an associate professor in the Department of Medicine at SUNY Downstate Medical Center, who was not involved in the study.
Jean-Louis said more research was needed, but noted that some sleep conditions like short sleep and obstructive sleep apnea bear two of the same biomarkers as cardiovascular disease -- C-reactive protein and interleukin-6 -- which are proteins linked to inflammation.
The body's regulatory cycle for sleeping and wakefulness, known as circadian rhythms, could also play a role, according to Edward Fisher, professor of cardiovascular medicine at New York University.
"It is known that animals with disrupted circadian rhythms develop metabolic changes that, if they occurred in people, would increase heart disease risk," said Fisher, who also was not a part of the study.
"Overall, independent of the exact mechanism, the association shown seems plausible, and is yet another reason to do as the authors advise -- seek professional help for better sleep," he added.
"Besides improving the general quality of life, it might even provide cardiovascular benefits."
<한글기사>
불면증, 심장발작 위험 높인다
불면증이 심장발작 위험을 높일 수 있다는 연구 결과가 나왔다.
노르웨이 과학기술대학의 라르스 레우산(Lars Laugsand) 박사는 남녀 5만3천명 을 대상으로 수면 습관을 조사하고 11년 동안 지켜본 결과 거의 매일 잠들기가 어려 운 사람은 제대로 잠을 자는 사람에 비해 심장발작 발생률이 평균 45% 높은 것으로 나타났다고 밝힌 것으로 헬스데이 뉴스가 24일(현지시간) 보도했다.
또 중간에 잠을 깨는 사람은 푹 자는 사람에 비해 심장발작 위험이 30%, 아침에 일어나 개운한 기분을 느끼지 못하는 사람은 수면으로 피로가 회복된 사람에 비해 2 7% 높은 것으로 나타났다.
조사 대상자들의 연령, 성별, 결혼 여부, 교육수준, 혈압, 콜레스테롤, 당뇨병, 체중, 운동, 교대근무, 우울증 등 다른 요인들을 고려했지만 불면증과 심장발작 사 이의 연관성에는 변함이 없었다고 레우산 박사는 밝혔다.
다만 연구팀이 한 가지 고려하지 못한 것은 심장발작을 포함한 심혈관질환의 위 험요인이 될 수 있는 폐쇄성 수면무호흡증이다. 이는 잠잘 때 심하게 코를 골면서 간헐적으로 호흡이 끊어지는 수면장애를 말한다.
불면증이 심장발작과 연관이 있는 이유는 분명하지 않지만 수면장애가 심장발작 의 위험인자인 혈압 또는 염증에 영향을 미치기 때문으로 생각된다고 레우산 박사는 설명했다.
이 연구결과는 미국심장학회 학술지 '순환(Circulation)' 온라인판(10월24일자) 에 실렸다.
