Sleep duration and growth outcomes across the first two years of life in the GUSTO study.

BACKGROUND AND AIM: Short sleep duration is thought to be a factor contributing to increased body mass index (BMI) in both school-age children and adults. Our aim was to determine whether sleep duration associates with growth outcomes during the first two years of life. STUDY DESIGN: Participants included 899 children enrolled in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort study. Anthropometric data (weight and body length) and parental reports of sleep duration were collected at 3, 6, 9, 12, 18, and 24 months of age. A mixed-model analysis was used to evaluate the longitudinal association of BMI and body length with sleep duration. In subgroup analyses, effects of ethnicity (Chinese, Indian, and Malay) and short sleep at three months of age (≤12 h per day) were examined on subsequent growth measures. RESULTS: In the overall cohort, sleep duration was significantly associated with body length (ß = 0.028, 95% confidence interval [CI] 0.002-0.053, p = 0.033), but not BMI, after adjustment for potential confounding factors. Only in Malay children, shorter sleep was associated with a higher BMI (ß = -0.042, 95% CI -0.071 to -0.012, p = 0.005) and shorter body length (ß = 0.079, 95% CI 0.030-0.128, p = 0.002). In addition, shorter sleep was associated with a higher BMI and shorter body length in children who slept ≤12 h per day at three months of age. CONCLUSION: The association between sleep duration and growth outcomes begins in infancy. The small but significant relationship between sleep and growth anthropometric measures in early life might be amplified in later childhood.

Effects of exposure to intermittent versus continuous red light on human circadian rhythms, melatonin suppression, and pupillary constriction.

Exposure to light is a major determinant of sleep timing and hormonal rhythms. The role of retinal cones in regulating circadian physiology remains unclear, however, as most studies have used light exposures that also activate the photopigment melanopsin. Here, we tested the hypothesis that exposure to alternating red light and darkness can enhance circadian resetting responses in humans by repeatedly activating cone photoreceptors. In a between-subjects study, healthy volunteers (n = 24, 21-28 yr) lived individually in a laboratory for 6 consecutive days. Circadian rhythms of melatonin, cortisol, body temperature, and heart rate were assessed before and after exposure to 6 h of continuous red light (631 nm, 13 log photons cm(-2) s(-1)), intermittent red light (1 min on/off), or bright white light (2,500 lux) near the onset of nocturnal melatonin secretion (n = 8 in each group). Melatonin suppression and pupillary constriction were also assessed during light exposure. We found that circadian resetting responses were similar for exposure to continuous versus intermittent red light (P = 0.69), with an average phase delay shift of almost an hour. Surprisingly, 2 subjects who were exposed to red light exhibited circadian responses similar in magnitude to those who were exposed to bright white light. Red light also elicited prolonged pupillary constriction, but did not suppress melatonin levels. These findings suggest that, for red light stimuli outside the range of sensitivity for melanopsin, cone photoreceptors can mediate circadian phase resetting of physiologic rhythms in some individuals. Our results also show that sensitivity thresholds differ across non-visual light responses, suggesting that cones may contribute differentially to circadian resetting, melatonin suppression, and the pupillary light reflex during exposure to continuous light.

Percutaneous pin removal in the outpatient clinic--do children require analgesia?: a randomized controlled trial.

BACKGROUND: Percutaneous pins used in the surgical fixation of fractures in children are often removed in the outpatient clinic without the administration of analgesia. Pin removal can be a cause of anxiety for children, parents, and caregivers. Relatively little is known about the requirement of analgesia for this procedure. In a randomized controlled trial, we evaluated whether oral acetaminophen or ibuprofen reduced the pain experienced during pin removal. METHODS: Participating in the study were 240 children between the ages of five and twelve years who had two or three percutaneous pins in the elbow following treatment of a supracondylar humeral fracture or a lateral humeral condyle fracture with closed reduction and percutaneous pinning. The patients were randomized into one of three groups (n = 80) allocated to receive acetaminophen, ibuprofen, or vitamin C (placebo) an hour before pin removal. A pain score was obtained and heart rate measured before pin removal, immediately following the procedure, and ten minutes after pin removal. RESULTS: No significant differences were found among the study groups in terms of the demographic data of sex, age, side of injury, or number of pins. Pain score and heart rate did not exhibit differences that were either statistically significant or clinically relevant. The change from baseline did not differ significantly among the groups for either measure at either of the follow-up times post pin removal. Immediately after pin removal, the mean difference in pain score (and 95% confidence interval [CI]) between the acetaminophen group and the ibuprofen group was 0.10 (-1.03 to 1.23); between the acetaminophen group and the placebo group, 0.35 (-0.78 to 1.48); and between the ibuprofen group and the placebo group, 0.25 (-0.88 to 1.38). The CIs excluded a clinically relevant difference. Pain scores and heart rates returned to preprocedural baseline levels within ten minutes following pin removal. CONCLUSIONS: Neither acetaminophen nor ibuprofen significantly reduced the pain score or heart rate associated with percutaneous pin removal in children as compared with the placebo. The oral analgesics administered were clinically equivalent to the placebo. These results suggest that non-narcotic analgesia use does not significantly reduce pain or heart rate associated with percutaneous pin removal in children.