A study recently published in The Lancet produced normative values for sleep data in healthy adults, which may help aid in future research, particularly when obtaining polysomnographic control data is difficult.
Researchers included 5273 participants from 169 studies that were published between 2007 and 2016 in this meta-analysis. These studies included data on polysomnographic parameters collected overnight using recent American Academy of Sleep Medicine scoring criteria. Any studies including participants with treatments or conditions that might affect sleep were excluded. Pooled estimates of 14 polysomnographic factors constituted the study end points, using a random-effects generic inverse meta-analysis to estimate each factor. Multivariate mixed-effects meta-regressions were used to assess the effects of sex and age. Cochran’s Q test with a P value <.10 was used to assess heterogeneity.
For each successive 10 years of age, total sleep time decreased by 10.1 minutes (95% CI, 7.5-12.8), sleep efficiency decreased by 2.1% (95% CI, 1.5%-2.6%), wake after sleep onset increased by 9.7 minutes (95% CI, 6.9-12.4), arousal index increased by 2.1 events/h (95% CI, 1.5-2.6), and sleep onset latency increased by 1.1 minutes (95% CI, 0.3-1.9). Additionally, percentage of N1 sleep increased by 0.5% (95% CI, 0.1%-0.8%), apnea-hypopnea index increased by 1.2 events/h (95% CI, 0.9-1.4), minimum oxygen saturation decreased by 1.8% (95% CI, 1.3%-2.3%), mean oxygen saturation decreased by 0.6% (95% CI, 0.5%-0.7%), and periodic limb movement increased by 1.2 events/h (95% CI, 0.8-1.6).
No significant correlations were found between age and percentage of N2 sleep, N3 sleep, or rapid eye movement (REM) sleep. For every 10% increase in the proportion of men participating in this study, REM latency decreased by 0.9 minutes (95% CI, 0.1-1.6), arousal index increased by 0.3 events/h (95% CI, 0.0-0.5), mean oxygen saturation decreased by 0.1% (95% CI, 0.0-0.1), and apnea-hypopnea index increased by 0.2 events/h (95% CI, 0.1-0.3).
Limitations to this study included the potential for including participants with undiagnosed conditions, a lack of representation of adults >65 years, a lack of studies reporting separate data for men and women, high variability in the apnea-hypopnea index in those >50 years, and the use of the 2007 American Academy of Sleep Medicine recommendations for apnea-hypopnea index normative values.
The researchers concluded that the meta-analysis “is the largest analysis of published normative sleep data to date and provides robust control values for clinical use and various future research studies where it might be difficult to obtain polysomnographic controls. The summary values provide data to establish normative values in a variety of settings and suggest degrees of variance that could be helpful when preparing sample size calculations. The resulting normative trends by age and sex might also be hypothesis-generating for a broad range of investigations.”
Disclosures: Dr Boulos reports financial associations with pharmaceutical companies.
Boulos MI, Jairam T, Kendzerska T, Im J, Mekhael A, Murray BJ. Normal polysomnography parameters in healthy adults: a systematic review and meta-analysis [published online April 18, 2019]. Lancet. doi:10.1016/S2213-2600(19)30057-8