Is sleep duration related to obesity? A critical review of the epidemiological evidence

Sleep Duration and Cancer Risk: a Systematic Review and Meta-analysis of Prospective Studies

“…The mechanisms underlying the association between short or long sleep duration and cancer risk are not fully understood. Two potential biological mechanisms have been proposed to explain how short sleep duration directly influenced cancer incidence, including impaired immune function and metabolic pathways related to obesity (Knutson et al, 2007;Marshall et al, 2008). Moreover, the altered melatonin secretion has also been shown as a potential risk factor of cancer (Stevens et al, 2007;Benke et al, 2013).…”

Effects of three weeks of mild sleep restriction implemented in the home environment on multiple metabolic and endocrine markers in healthy young men

“…The lack of adequate interventional data has been highlighted repeatedly [14][15][16] and in this study we conducted a controlled trial in healthy lean individuals using a moderate level of sleep-loss (1.5 h per night) over a period of 3 weeks while participants were living in their 5 normal environment, using a similar sleep protocol to that previously described by Zielinski and colleagues in older long-sleepers [17,18]. We also used a parallel group design in which the sleep restriction was compared to a control group with no change in sleep duration, rather than a cross-over design in which the effects of sleep restriction are compared to a period of recovery sleep-extension or recovery [19].…”

Sleep and obesity: an introduction

“…A meta-analysis [12] showed that children with poor or disturbed sleep are about twice as likely to have obesity and adults with poor sleep have a probability of 1.5 more than good sleepers to be obese. In children, the cross-sectional results are also confirmed by longitudinal studies, systematic reviews and meta-analyses; on the contrary from adolescence to adulthood, results are more controversial [13,14]. A recent systematic review [9] examined 20 longitudinal studies published between October 2004 and October 2010, highlighting again consistency of the results in children and inconsistency in adults.…”

“…First of all, the relationship between sleep duration and obesity in adults may be nonlinear and U-shaped. In other words, there may be an optimal duration of sleep (around 7 h) that is associated with health and well-being while sleep of longer or shorter duration may increase the risk of obesity [14,15]. This explanation is consistent with the results of a longitudinal study by Theorell-Haglow and colleagues [16] who showed that in a wide sample of women aged 46 ± 17.5, the subsample of participants aged \40 showed higher obesity if they slept \6 h or more than 9 h. The second explanation that may be advanced is the eventual different composition of the samples.…”