Rationale

Evidence suggests that among children under 2 years of age, 12 or more hours of sleep in a 24-hour period is protective of obesity at age 3. Among children aged 2–5, 11 or more hours of sleep has been found to be associated with lower obesity risk. Age-appropriate sleep durations from the National Sleep Foundation include (NSF, 2011)

  • newborns, less than 3 months: 10.5–18 hours in a 24-hour period;
  • infants, 3 months to <12 months: 9–12 hours during the night and 30-minute to 2 hour naps one to four times a day;
  • toddlers, 1 year to <3 years: 12–14 hours in a 24-hour period; and
  • preschoolers, 3 years to <5 years: 11–13 hours in a 24-hour period.

Evidence suggests an inverse association between sleep duration and obesity in children (Agras et al., 2004; Bell and Zimmerman, 2010; Landhuis et al., 2008; Reilly et al., 2005; Taveras et al., 2008). All published studies have reported an association between shorter sleep duration and increased obesity risk in children across the pediatric age range (Cappuccio et al., 2008; Chen et al., 2008; Patel and Hu, 2008).

One of the largest studies involved a Japanese birth cohort of 8,274 children. At ages 6 to 7, the odds ratios for obesity were 1.49, 1.89, and 2.87 for those sleeping 9–10, 8–9, and less than 8 hours, respectively, compared with those obtaining at least 10 hours of sleep and after adjusting for sex, parental obesity, and other lifestyle factors (Sekine et al., 2002). Similar findings have been reported from Portugal (Padez et al., 2005), Spain (Vioque et al., 2000), France (Locard et al., 1992), and Germany (von Kries et al., 2002). Prospectively, a UK study of 8,234 children showed that sleep duration at age 38 months predicted obesity at age 7, with odds ratios of 1.45, 1.35, and 1.04 for children sleeping less than 10.5, 10.5–10.9, and 11.0–11.9 hours, respectively, compared with those sleeping at least 12 hours (Reilly et al., 2005). In another study, 4-year-old children who slept less than 10.5 hours per weekday night had elevated odds of obesity compared with children who slept at least 10.5 hours (Anderson and Whitaker, 2010). Short sleep duration has been associated with increased television viewing and reduced participation in organized sports (Locard et al., 1992; Taveras et al., 2008; von Kries et al., 2002).

Poor sleep routines have also been associated with obesity in children. In one study, irregular sleeping habits between 2 and 4 years of age were associated



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