Table 2.
A summary of systematic reviews and meta-analyses that assessed the relationship between sleep duration and health outcomes (after 2015)
| Author | Design and study population | Study details |
|---|---|---|
| Cancer/mortality | ||
| Stone et al.[17] | A meta-analysis of 32 studies were included representing over 73,000 deaths in cancer survivors | Pooled hazards ratios for short and long sleep duration (≥9-10 h) for all cancer-specific mortality were 1.03 (95% CI 1.00-1.06) and 1.09 (95% CI 1.04-1.13) (≤5-6 h), respectively These associations were maintained when stratified by sex and sampling frame |
| Chen et al.[18] | A meta-analysis of 65 studies from 25 articles, involving 1,550,524 participants and 86,201 cancer cases | The categorical meta-analysis revealed that neither short (≤6 h) nor long sleep duration (≥ was associated with increased cancer risk Subgroup analysis revealed that short sleep duration was associated with cancer risk among Asians (OR=1.36; 95% CI: 1.02-1.80) and long sleep duration significantly increased the risk of colorectal cancer (OR=1.21; 95% CI: 1.08-1.34) |
| da Silva et al.[19] | A meta-analysis of 27 cohort studies of >70,000 elderly individuals and followed up from 3.4 to 35 years | Long (>10 h) and short sleep (<6 h) duration was associated with increased all-cause mortality (RR=1.33 and RR=1.07, respectively), compared with the reference category For cardiovascular mortality, the pooled relative risks were 1.43 for long sleep and 1.18 for short sleep Daytime napping ≥30 min was associated with risk of all-cause mortality (RR=1.27), but longer sleep duration (≥2.0 h) was not |
| Lu et al.[20] | A meta-analysis of 10 studies including 415,865 participants | A J-shaped nonlinear trend was found between sleep duration and breast cancer incidence (P-nonlinear=0.012); compared with the reference hours (6 h or 7 h), with increasing sleep hours, the risk of breast cancer increased (P-trend=0.028) |
| Jike et al.[21] | A meta-analysis of 137 prospective cohort studies, including 5,134,036 participants | Long sleep was significantly associated with mortality (RR, 1.39; 95% CI, 1.31-1.47), incident type 2 diabetes (1.26, 1.11-1.43), cardiovascular disease (1.25, 1.14-1.37), stroke (1.46, 1.26-1.69), coronary heart disease (1.24, 1.13-1.37), and obesity (1.08, 1.02-1.15). Long sleep was not significantly related to incident hypertension (1.01, 0.95-1.07) |
| Itani et al.[22] | A meta-analysis of 153 studies comprising 5,172,710 participants | Short sleep was significantly associated with the mortality outcome (RR, 1.12; 95% CI, 1.08-1.16). Similar significant results were observed in Type 2 diabetes (1.37, 1.22-1.53), hypertension (1.17, 1.09-1.26), cardiovascular diseases (1.16, 1.10-1.23), coronary heart diseases (1.26, 1.15-1.38), and obesity (1.38, 1.25-1.53) |
| Yin et al.[23] | A meta-analysis of 67 articles with 141 independent reports | U-shaped associations were indicated between sleep duration and risk of all outcomes, with the lowest risk observed for short sleep duration (<7 h sleep duration per day), which was varied little by sex For all-cause mortality, the RR was 1.06 (95% CI, 1.04-1.07) per 1 h reduction below 7 h; when sleep duration was>7 h per day, the pooled RR was 1.13 (95% CI, 1.11-1.15) per 1 h increment For total cardiovascular disease, the pooled RR was 1.06 (95% CI, 1.03-1.08) per 1 h reduction and 1.12 (95% CI, 1.08-1.16) per 1 h increment of sleep duration For coronary heart disease, the pooled RR was 1.07 (95% CI, 1.03-1.12) per 1 h reduction and 1.05 (95% CI, 1.00-1.10) per 1 h increment of sleep duration For stroke, the pooled RR was 1.05 (95% CI, 1.01-1.09) per 1 h reduction and 1.18 (95% CI, 1.14-1.21) per 1 h increment of sleep duration |
| Kwok et al.[24] | A meta-analysis of 74 studies including 3340 684 participants with 242,240 deaths among 2,564,029 participants Participants who reported death events were reviewed |
Self-reported duration of sleep>8 h was associated with a moderate increased risk of all-cause mortality, with risk ratio, 1.14 (1.05-1.25) for 9 h, risk ratio, 1.30 (1.19-1.42) for 10 h, and risk ratio, 1.47 (1.33-1.64) for 11 h No significant difference was identified for periods of self-reported sleep <7 h |
| Other meta-analyses in adults | ||
| Xi et al.[25] | A meta-analysis of 12 studies involving 18,720 participants with metabolic syndrome and 70,833 controls | Short sleep duration was associated with increased risk of MS (OR=1.27, 1.09-1.47) |
| Kruisbrink et al.[26] | A meta-analysis of 13 studies that assessed the longitudinal relationships between sleep disturbances (of quantity and quality) and dyslipidemia in the general population | Short sleep (≤5-7 h) was associated with a risk of 1.01 (95% CI 0.93-1.10) of developing dyslipidemia; long sleep (≥9 h) was associated with a risk of 0.98 (95% CI 0.87-1.10) for dyslipidemia |
| Irwin et al.[27] | A meta-analysis of studies (>50,000 participants) that assessed the effects of sleep disturbance, sleep duration, and inflammation in adult humans | Long sleep duration (>8 h), but not short sleep duration (<8 h), are associated with increases in markers of systemic inflammation |
| Anothaisintawee et al.[28] | A meta-analysis of 36 studies (1,061,555 participants) on sleep duration and diabetes type 2 | Pooled RRs of sleeping≤5 h and 6 h were, respectively, 1.48 (1.25,1.76), and 1.18 (1.10,1.26) |
| Wang et al.[29] | A meta-analysis of 17 articles involving 17,841 incident cases of CAD among 517,440 participants | A U-shaped relationship was detected between sleep duration and risk of coronary heart disease, with the lowest risk at 7-8 h/day The combined RR of CAD was 1.11 (1.05-1.16) for a reduction of 1 h of sleep (compared to 7 h/day) |
| He et al.[30] | A meta-analysis of 16 prospective studies, involving 528,653 participants with 12,193 stroke events | The lowest risk observed with sleeping for 7 h/day Short sleep durations were only significantly associated with nonfatal stroke A slightly decreased risk of ischemic stroke among short sleepers Long sleepers had a higher predicted risk of total stroke than short sleepers (the pooled RR: 4 h: 1.17 [0.99-1.38]; 5 h: 1.17 [1.00-1.37]; 6 h: 1.10 [1.00-1.21]; 8 h: 1.17 [1.07-1.28]; 9 h: 1.45 [1.23-1.70]; 10 h: 1.64 [1.4-1.92]) |
| Li et al.[31] | A meta-analysis of 11 articles with 16 independent reports (sleep duration and stroke) | The pooled RR for stroke events was 1.07 (1.02-1.12) for each 1 h shorter sleep duration (<7 h/day) and 1.17 (1.14-1.20) for each 1 h increase of sleep duration (>7 h/day)The pooled RR for stroke mortality was 1.17 (95% CI 1.13-1.20) per 1 h increase of sleep duration |
| Lo et al.[32] | A total of 35 independent samples (n=97,264) from 11 cross-sectional and seven prospective cohort studies of adults >55 years were included Sleep durations ranged from 5 to 9 h across studies, 7 h, 8 h, and 7-8 h were most commonly used |
Self-reported short and long sleep increased the odds for poor cognitive function by 1.40 (CI=1.27-1.56) and 1.58 times (CI=1.43-1.74), respectively |
| Meta-analyses in children | ||
| Shan et al.[33] | A meta-analysis of 33 studies (including 3 randomized controlled trials and 30 observational studies) | A U-shaped dose-response relationship was observed between sleep duration and risk of type 2 diabetes, with the lowest risk observed at a sleep duration category of 7-8 h/day The pooled relative risks for type 2 diabetes were 1.09 (95% CI 1.04-1.15) for each 1 h shorter sleep duration <7 h |
| Felső et al.[34] | A systematic review 33 studies (including 3 randomized controlled trials and 30 observational studies Most of the studies were conducted in America Objective assessment of sleep duration via wrist worn accelerometer in 9 and waist worn accelerometer in 14 studies |
Negative relationship between sleep time and different measures of adiposity |
| Krietsch et al.[35] | A systematic review of 86 studies of youth (0-18 years), which investigated the relationship between sleep and dietary intake, altered eating behavior, physical/sedentary activity, or hormones regulating hunger/satiety | No cross-sectional association between sleep duration and caloric intake and shorter or later sleep associating with greater sedentary or screen time |
| Chiu et al.[36] | This is a systematic review of 13 reports that included a total of 598,281 participants for a systematic review, and 12 reports were further used for a dose-response meta-analysis that assessed the association between sleep duration and suicidality in adolescents | Strong curvilinear dose-response associations were obtained for both suicidal ideation and attempts, with the lowest suicidal ideation and attempt risks at sleep durations of 8 h and 8-9 h/day (all P-nonlinearity <0.001)A linear dose-response relationship between sleep duration and suicide plans (pooled OR=0.89, 95% CI=0.88-0.90) was obtained, indicating that the risk of suicide plans statistically decreased by 11% for every 1 h increase in sleep duration |
| Short et al.[37] | A meta-analysis of 19 studies that objectively assessed the relationship between sleep duration and cognitive function in children aged 5-13 years | A significant effect (r=0.06) was found between sleep duration and cognition, suggesting that longer sleep durations were associated with better cognitive functioning |
| Miller et al.[38] | A meta-analysis of 52 studies that assessed the prospective relationship between sleep and obesity in a pediatric population | Short sleep was associated with a greater risk of developing overweight or obesity in infancy (RR: 1.40; 95% CI 1.19-1.65; P<0.001), early childhood (RR: 1.57; 1.40-1.76; P<0.001), middle childhood (RR: 2.23; 2.18-2.27; P<0.001), and adolescence (RR: 1.30; 1.11-1.53; P<0.002) |
| Anothaisintawee et al.[28] | A meta-analysis of 12 prospective cohort studies that estimated the associations between sleep duration and obesity/BMI in children | Short sleep duration was significantly associated with obesity (RR: 1.45; 95% CI: 1.14-1.85). |
| Chaput et al.[39] | A systematic review of 69 studies (included 148,524 unique participants from 23 countries) that assessed the association sleep duration and health indicators in children (0-4 years) | Despite important limitations in the available evidence, longer sleep duration was generally associated with better body composition, emotional regulation, and growth in children aged 0-4 years Shorter sleep duration was also associated with longer screen time use and more injuries |
| Wu et al.[40] | A meta-analysis of 13 articles were included, involving 35,540 children and adolescents from around the world | The OR in short sleepers for obesity of the pooled was 1.71 (1.36-2.14) |
| Zhang et al.[41] | His systematic review aimed to summarize correlates of sleep duration in children under 5 years of age One-hundred and sixteen studies, representing 329,166 children, met the inclusion criteria, with a high risk of bias in 62 included studies |
Among the associations studied four or more times, correlates of nap duration were child’s age and nighttime sleep onset/bedtime; correlates of nighttime sleep duration were household income, parent marital status, parental adiposity level, nighttime sleep duration at younger age, nighttime sleep onset/bedtime, nighttime sleep wakeup time, and frequency of current bedtime routine; correlate of total sleep duration was screen time |
| Morrissey et al.[42] | A systematic review of multiple sleep dimensions: 12 were included for detailed review | A significant inverse association between sleep duration and measured weight status |
CI=Confidence interval, OR=Odds ratio, RR=Relative risk, BMI=Body mass index, MS=Multiple sclerosis, CAD=Coronary artery disease