Sleep duration of underserved minority children in a cross-sectional study

BACKGROUND Short sleep duration has been shown to associate with increased risk of obesity. Childhood obesity is more prevalent among underserved minority children. The study measured the sleep duration of underserved minority children living in a large US urban environment using accelerometry and its relationship with BMI, socioeconomic status (SES), gender, ethnicity and physical activity. METHODS Time spent on sleep and physical activity among 333 Hispanic and 150 black children (9-12 y) was measured objectively by accelerometry over 5-7 consecutive days. The children were recruited at 14 underserved community centers in Houston, Texas, between January 2009 and February 2011. Body weight and height were measured in duplicate. RESULTS The majority of children (88.8%) wore the monitor for 6 consecutive days. The children slept 8.8 ± 0.6 (mean ± SD) h/d and spent 45 ± 24 min/d on moderate-vigorous physical activity (MVPA). Hispanic children slept 0.2 h/d longer (P<0.001) than black children. Obese children slept 0.2 h/d less (P<0.02) than normal-weight children. SES had no effect on sleep duration. There was a significant interaction between gender and age (P<0.03); girls aged 11-12 y slept 0.3 h/d less than boys and the younger girls. Children slept 0.6 h/d longer (P<0.001) during the weekend than weekdays. No relation was detected between sleep duration and MVPA time. CONCLUSIONS Minority children living in a large metropolitan area in the US are not meeting the National Sleep Foundation recommendation for sleep duration of 10-11 h/d. Longitudinal studies based on objective measures are needed to establish causality between sleep duration and obesity risk among minority children.