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Meta-Analysis
. 2015 Dec 1;38(12):1945-53.
doi: 10.5665/sleep.5246.

Daytime Napping and the Risk of Cardiovascular Disease and All-Cause Mortality: A Prospective Study and Dose-Response Meta-Analysis

Tomohide Yamada  1 , Kazuo Hara  1 , Nobuhiro Shojima  1 , Toshimasa Yamauchi  1 , Takashi Kadowaki  1
Affiliations
Meta-Analysis

Daytime Napping and the Risk of Cardiovascular Disease and All-Cause Mortality: A Prospective Study and Dose-Response Meta-Analysis

Tomohide Yamada et al. Sleep. .

Abstract

Study objectives: To summarize evidence about the association between daytime napping and the risk of cardiovascular disease and all-cause mortality, and to quantify the potential dose-response relation.

Design: Meta-analysis of prospective cohort studies.

Methods and results: Electronic databases were searched for articles published up to December 2014 using the terms nap, cardiovascular disease, and all-cause mortality. We selected well-adjusted prospective cohort studies reporting risk estimates for cardiovascular disease and all-cause mortality related to napping. Eleven prospective cohort studies were identified with 151,588 participants (1,625,012 person-years) and a mean follow-up period of 11 years (60% women, 5,276 cardiovascular events, and 18,966 all-cause deaths). Pooled analysis showed that a long daytime nap (≥ 60 min/day) was associated with a higher risk of cardiovascular disease (rate ratio [RR]: 1.82 [1.22-2.71], P = 0.003, I(2) = 37%) compared with not napping. All-cause mortality was associated with napping for ≥ 60 min/day (RR: 1.27 [1.11-1.45], P < 0.001, I(2) = 0%) compared with not napping. In contrast, napping for < 60 min/day was not associated with cardiovascular disease (P = 0.98) or all-cause mortality (P = 0.08). Meta-analysis demonstrated a significant J-curve dose-response relation between nap time and cardiovascular disease (P for nonlinearity = 0.01). The RR initially decreased from 0 to 30 min/day. Then it increased slightly until about 45 min/day, followed by a sharp increase at longer nap times. There was also a positive linear relation between nap time and all-cause mortality (P for non-linearity = 0.97).

Conclusions: Nap time and cardiovascular disease may be associated via a J-curve relation. Further studies are needed to confirm the efficacy of a short nap.

Keywords: all-cause mortality; cardiovascular disease; meta-analysis; napping; siesta.

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Figures

Figure 1
Figure 1
Literature search and study selection.
Figure 2
Figure 2
Meta-analysis of the incidence rate ratio of cardiovascular disease. Plots showing the association between daytime napping and the risk of cardiovascular disease. *Number of available datasets. In seven reports, the results were stratified by sex (male/female), while results were stratified by age group in 1 report (50 to 64 years, 65 to 74 years, and ≥ 75 years), by nocturnal sleep duration in 1 report (< 7 h, 7 to 7.9 h, 8 to 8.9 h, 9 to 9.9 h, and ≥ 10 h), and by the presence of hypertension in 1 report (hypertension group, non-hypertension group). CI, confidence interval.
Figure 3
Figure 3
Meta-analysis of the incidence rate ratio of all-cause mortality. Plots showing the association between daytime napping and the risk of all-cause mortality. *Number of available datasets. CI, confidence interval.
Figure 4
Figure 4
Dose-response relationship between nap time and the risk of cardiovascular diseases. CI, confidence interval.
Figure 5
Figure 5
Dose-response relationship between nap time and the risk of all-cause mortality. CI, confidence interval.
See this image and copyright information in PMC

Comment in

References

    1. Cappuccio FP, Cooper D, D'Elia L, Strazzullo P, Miller MA. Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies. Eur Heart J. 2011;32:1484–92. - PubMed
    1. Cappuccio FP, D'Elia L, Strazzullo P, Miller MA. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010;33:585–92. - PMC - PubMed
    1. Trichopoulos D, Tzonou A, Christopoulos C, Havatzoglou S, Trichopoulou A. Does a siesta protect from coronary heart disease? Lancet. 1987;2:269–70. - PubMed
    1. Jung KI, Song CH, Ancoli-Israel S, Barrett-Connor E. Gender differences in nighttime sleep and daytime napping as predictors of mortality in older adults: the Rancho Bernardo study. Sleep Med. 2013;14:12–9. - PMC - PubMed
    1. Stang A, Dragano N, Moebus S, et al. Heinz Nixdorf Recall Investigative Group. Midday naps and the risk of coronary artery disease: results of the Heinz Nixdorf Recall Study. Sleep. 2012;35:1705–12. - PMC - PubMed

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