A study, published in the European Heart Journal, reports that a good sleep pattern can offset some risks of cardiovascular disease.
Prof Jeremy Pearson FMedSci, Associate Medical Director, British Heart Foundation (BHF), said:
“This large-scale observational study confirms previous findings that sub-optimal sleep patterns are associated with increased risk of future heart attack or stroke.
“In a cohort of around 380,000 middle aged adults without pre-existing heart attack or stroke, there were just over 7,000 heart attacks and strokes over a median follow-up period of 8.5 years. In those with the most disturbed sleep pattern (about 4% of the cohort) the event rate was about a third higher than in those with healthy sleep scores.
“The research is of high quality and has analysed different types of altered sleep pattern in more detail than previous studies. Because the participants are from the UK Biobank cohort, the authors were also able to stratify them according to a composite cardiovascular genetic risk score, which has not previously been done.
“Despite this, the results reveal little that is really new. As an observational study, it cannot prove causality and there is a strong likelihood that sleep patterns additionally reflect other aspects of health that affect cardiovascular risk.
“The novel assessment of sleep behaviour did not pinpoint any one behaviour type as being more strongly associated with cardiovascular risk. Finally, the associations seen were independent of the genetic risk score.”
Dr Dipender Gill, Clinical Research Training Fellow, Imperial College London, said:
“This is an interesting study that adds to the growing body of literature supporting an association between sleep patterns and health outcomes. The authors provide evidence to support that some sleep behaviours may be associated with better cardiovascular outcomes than others.
“However, the interpretation and discussion in the paper is also appropriately cautious, as the observational design of the study makes it difficult to infer causal effects of sleep habits on cardiovascular outcomes. There remains the possibility that the associations are attributable to unmeasured or unknown confounding factors that affect both sleep patterns and cardiovascular risk. It is also important to note that the authors found no evidence of interaction between sleep patterns and genetic susceptibility to cardiovascular disease. Thus, if there is a beneficial effect of some sleep behaviours over others, these would likely reduce cardiovascular risk in all individuals, irrespective of their genetic predisposition to disease.”
Prof Stephen MacMahon, Principal Director, The George Institute for Global Health, said:
“The relationship between sleep and cardiovascular disease has been debated for many years. In previous studies it was difficult to disentangle risks associated with poor sleep from risks associated with other causes of cardiovascular disease, and this is also the case here. People with poor sleep quality were more likely to have diabetes, hypertension and a range of other risk factors including obesity, which reduces the quality of sleep through snoring and sleep apnoea as well as increasing cardiovascular disease risks. So, it’s the chicken or the egg dilemma. Only clinical trials of strategies to improve sleep can resolve this, although those that have been conducted1 to date have not shown clear evidence of benefits.”
Prof Paul Evans, Professor of Cardiovascular Science, University of Sheffield, said:
“This study is important because it demonstrates that individuals with a healthy sleep pattern have a reduced risk of angina, heart attack and stroke. This could be because cardiovascular health is linked to our body’s natural rhythm of sleep and wakefulness. Overall, the study adds weight to the importance of lifestyle choices in maintaining cardiovascular health and suggests that a good night’s sleep may be beneficial alongside regular exercise and a healthy diet.”
Prof Derk-Jan Dijk, Professor of Sleep Physiology, University of Surrey, said:
“The novel aspect of this UK biobank based prospective study (median 8.5 years follow up) of the relation of sleep to cardiovascular disease (CVD) is that it uses a ‘composite’ sleep health score which combines five aspects of sleep (or sleep factors:) assessed in separate questions about sleep in the UK biobank: chronotype (if you’re a morning and evening person), habitual sleep duration, insomnia, snoring and excessive daytime sleepiness. You are a healthy sleeper if you are a morning type, sleep 7-8 h, never/rarely have insomnia symptoms, don’t snore and don’t experience frequent excessive daytime sleepiness. The study looked at those with no CVD at the start of the study and found that, compared to unhealthy sleepers, healthy sleepers had an approximately 35% reduced risk of developing CVD. Other studies had previously identified that each of the sleep factors contributed to CVD risk.
“Another novel aspect of the study is that the authors looked at the interaction of CVD risk related to a polygenetic risk factor and the sleep health risk factor. The data show that ‘Participants with high genetic risk and poor sleep pattern had a more than 2.5-fold greater risk of CHD Coronary Heart Disease than participants with low genetic risk and healthy sleep pattern.’ The implication of this is that people with a high genetic risk for CVD can reduce their risk by improving their sleep health. Sleep is to some extent a modifiable risk factor, whereas genetic risk is not.
“The main weakness of the study is that the sleep measures were self-report. Further studies in which sleep is measured objectively are needed. In the ideal case we’d have interventional studies in which sleep is manipulated.”
‘Sleep patterns, genetic susceptibility, and incident cardiovascular disease: a prospective study of 385 292 UK Biobank participants’ by Fan et al. was published in European Heart Journal at 00:01 UK time on Wednesday 18th December.
Prof Jeremy Pearson: None
Dr Dipender Gill: “I have no relevant conflicts of interest to declare.”
Prof Stephen MacMahon: “None”
Prof Paul Evans: “No conflicts.”
Prof Derk-Jan: “No conflicts.”