Infant Regulation: Associations with Child Language Development in a Longitudinal Cohort.

OBJECTIVE: To determine whether infants who have regulatory problems (eg, sleeping, crying, and feeding problems) at 1 year of age are at increased risk of experiencing language difficulties at ages 5 and 11 years, compared with settled infants. STUDY DESIGN: Parent survey and child assessment data (n = 1131) were drawn from a longitudinal community cohort study. Latent Class Analysis identified 5 profiles of infant regulation including those who were settled (37%), had tantrums (21%), had sleep problems (25%), were moderately unsettled (13%), and severely unsettled (3%) at 12 months of age. Adjusted regression analyses examined associations between infant regulatory profiles and language ability (Clinical Evaluation of Language Fundamentals-fourth edition) at ages 5 and 11 years. RESULTS: Infants who were moderately unsettled had lower language scores at age 5 (adjusted mean difference, -3.89; 95% CI, -6.92 to -0.86) and were more likely to have language difficulties (aOR, 2.71; 95% CI, 1.28-5.75), than infants who were settled. Infants who were severely unsettled at 12 months of age, had lower language scores at ages 5 (adjusted mean difference, -7.71; 95% CI, -13.07 to -2.36) and 11 (adjusted mean difference, -6.50; 95% CI, -11.60 to -1.39), than infants who were settled. Severely unsettled infants were 5 times more likely to have language difficulties at age 5 than their settled counterparts (aOR, 5.01; 95% CI, 1.72-14.63). CONCLUSIONS: Children at 1 year of age with multiple regulatory problems are at an increased risk for poorer language skills at ages 5 and 11 years.

The Association of the Body Composition of Children with 24-Hour Activity Composition.

OBJECTIVES: To evaluate how the reallocation of time between sleep, sedentary time, light, and moderate-vigorous activities is associated with children's body composition. STUDY DESIGN: Population-based cross-sectional Child Health CheckPoint within the Longitudinal Study of Australian Children (n = 938 11-12 year-olds, 50% boys). Twenty-four hour activity composition via accelerometry (minutes/day of sleep, sedentary time, light, and moderate-to-vigorous physical activity [MVPA]) and 3-part body composition (percentage truncal fat, percentage nontruncal fat, and percentage fat-free mass) via bioelectrical impedance analysis were measured. We estimated differences in 3-part body composition associated with the incremental reallocation of time between activities, using dual-compositional regression models adjusted for sex, age, puberty, and socioeconomic position. RESULTS: Reallocation of time between MVPA and any other activity was strongly associated with differences in body composition. Adverse body composition differences were larger for a given MVPA decrease than were the beneficial differences for an equivalent MVPA increase. For example, 15 minutes less MVPA (relative to remaining activities) was associated with absolute percentage differences of +1.7% (95% CI 1.2; 2.4) for truncal fat, +0.8% (0.6; 1.2) for nontruncal fat, and -2.6% (-3.5; -1.9) for fat-free mass, and a 15-minute increase was associated with -0.7% (-0.9; -0.5) truncal fat, -0.4% (-0.5; -0.3) nontruncal fat, and +1.1% (0.9; 1.5) fat-free mass. Reallocations between sleep, sedentary time, and light physical activity were not associated with differences in body composition. CONCLUSIONS: Preventing declines in MVPA during inactive periods (eg, holidays) may be an important intervention goal. More MVPA, instead of other activities, may benefit body composition.