Long sleep duration, snoring ups risk of AF
Prolonged sleep duration is an independent predictor of higher incident atrial fibrillation (AF) risks in a Chinese population, reports a new prospective, population-based study.
“In this prospective, population-based, cohort study, long sleep duration independently predicted increased risk for incident AF as shown during a median 7.89 years of follow-up. In secondary analysis, prolong[ed] sleep duration was significantly associated with a higher risk of AF in people who snored,” the investigators said.
The investigators categorized 87,693 Chinese adults (mean age 50.54 years) without AF into three groups according to sleep duration: short (≤6 hours), average (7 hours) and long (≥8 hours). Sleep information such as duration and snoring was collected using self-reported questionnaires.
Participants were screened for AF using a 12-lead electrocardiogram during follow-up interviews every 2 years. Potential covariates such as age, sex, educational attainment, medical history, alcohol consumption and smoking status were also collected using questionnaires.
A short sleeping duration was reported by 24.16 percent (n=21,191) of the cohort, while 19.43 percent (n=17,035) had an average sleeping duration. A total of 49,467 participants (56.41 percent) reported at least 8 hours of sleep. [Sci Rep 2017;7:3679]
There were significant differences in age, gender distribution, educational attainment, current smoking status, current alcohol consumption, level of physical activity and snoring among the three groups of sleep duration (p<0.01 for all).
The most common comorbidity was hypertension which was reported in 42.87 percent (n=37,594) of the study sample. This was followed by dyslipidaemia (35.58 percent), diabetes mellitus (8.87 percent) and myocardial infarction (1.20 percent).
Over a median follow-up of 7.89 years, 322 cases of AF were reported; of these, 268 were in males while the remaining 54 were in females. Participants who developed AF were generally older (p<0.01), more frequently a smoker (p<0.01 and had higher BMI (p<0.01), uric acid (p<0.01) and high-sensitivity C-reactive protein (hs-CRP; p<0.01).
Analysis by sleep duration revealed that the crude incidence rates of AF for those with short, average and long sleep durations were 0.54, 0.42 and 0.53 cases per 1,000 person-years, respectively.
After adjusting for potential confounders, those in the short sleep duration group had similar risks of AF compared with those who had average sleep duration (hazard ratio [HR], 1.07; 95 percent CI, 0.75 to 1.53). In contrast, the long sleep duration group had higher AF risks (HR, 1.50; 1.07 to 2.10) compared with the average sleep duration group.
Gender stratification showed that both males (HR, 1.46; 1.02 to 2.10) and females (HR, 1.69; 0.70 to 4.11) who reported at least 8 hours of sleep had higher risks of AF. Similarly, those aged <60 years (HR, 1.86; 1.09 to 3.18) and ≥60 years (HR, 1.30; 0.94 to 2.00) had higher AF risks. None of the resulting associations reached statistical significance.
Interestingly, the combination of long sleep durations and snoring was significantly associated with an increased risk of AF (HR, 2.05 1.04 to 4.04).
While the current study is the first of its kind to provide insights on the relationship among sleep duration, snoring and AF, it still has some limitations, the investigators conceded. Among these were the self-reported nature of data collection, lack of data on naps and sleep quality, failure to exclude sleep apnoea patients, failure to account for possible changes in sleep duration and using a study sample that is not representative of the general population.
The said limitations, the investigators continued, may have interfered with the quality of the data by introducing bias, inflating the rates of AF and misrepresenting the actual sleeping duration of the participants.
Regardless, the current study was still able to produce solid preliminary data that “suggest that long sleep duration may cause increased risk of AF in a Chinese population,” the investigators said.
Aside from being the basis of future, more in-depth studies, the present findings suggest that significant beneficial effects towards stemming the growing prevalence of AF in China may be derived from encouraging and supporting individuals to pursue 7 hours of sleep per night, they added.