Trajectory of Body Mass Index from Ages 2 to 7 Years and Age at Peak Height Velocity in Boys and Girls.

OBJECTIVE: To examine the associations between body mass index (BMI) at 2-4 years and 5-7 years and age at peak height velocity (APHV), an objective measure of pubertal timing, among boys and girls from predominantly racial minorities in the US that have been historically underrepresented in this research topic. STUDY DESIGN: This study included 1296 mother-child dyads from the Boston Birth Cohort, a predominantly Black and low-income cohort enrolled at birth and followed prospectively during 1998-2018. The exposure was overweight or obesity, based on Centers for Disease Control and Prevention reference standards. The outcome was APHV, derived using a mixed effects growth curve model. Multiple regression was used to estimate the overweight or obesity-APHV association and control for confounders. RESULTS: Obesity at 2-4 years was associated with earlier APHV in boys (B in years, -0.19; 95% CI, -0.35 to -0.03) and girls (B, -0.22; 95% CI, -0.37 to -0.07). Obesity at 5-7 years was associated with earlier APHV in boys (B, -0.18; 95% CI, -0.32 to -0.03), whereas overweight and obesity at 5-7 years were both associated with earlier APHV in girls (overweight: B, -0.24; 95% CI, -0.40 to -0.08; obesity: B, -0.27; 95% CI, -0.40 to -0.13). With BMI trajectory, boys with persistent overweight or obesity and girls with overweight or obesity at 5-7 years, irrespective of overweight or obesity status at 2-4 years, had earlier APHV. CONCLUSIONS: This prospective birth cohort study found that overweight or obesity during 2-7 years was associated with earlier pubertal onset in both boys and girls. The BMI trajectory analyses further suggest that reversal of overweight or obesity may halt the progression toward early puberty.

Prenatal, Perinatal, and Early Childhood Factors Associated with Childhood Obstructive Sleep Apnea.

OBJECTIVES: To investigate prenatal, perinatal, and early childhood factors, including cord and early childhood plasma leptin, on a clinical diagnosis of obstructive sleep apnea (OSA) among children in the Boston Birth Cohort. STUDY DESIGN: We conducted a secondary analysis of 2867 mother-child pairs from the Boston Birth Cohort who were enrolled between 1998 and 2014 at Boston Medical Center and followed from birth to age 16 years. Child's OSA was defined based on clinical diagnoses documented in the medical record. Plasma leptin was measured in cord and early childhood blood samples. Logistic regression was used to examine individual and combined effects of early life factors on the risk of OSA, adjusting for potential confounders. RESULTS: The mean age of the study children was 6.39 years (SD = 3.77); 49.3% were girls, and 209 (7.3%) had ever been diagnosed with OSA. Four significant risk factors for OSA were identified: maternal obesity/diabetes during pregnancy (OR, 1.63; 95% CI, 1.21-2.21; P = .001), preterm/low birth weight (OR, 1.74; 95% CI, 1.30-2.32; P < .001), early childhood obesity (OR, 1.89; 95% CI, 1.37-2.62; P < .001), and high leptin levels in early childhood (OR, 1.94; 95% CI, 1.22-3.09; P = .005). The presence of all these 4 risk factors significantly amplified the odds of OSA by about 10 times (OR, 9.95; 95% CI, 3.42-28.93; P < .001) compared with those lacking these factors. CONCLUSIONS: Our findings, if further confirmed, provide new insight into the early life risk factors of pediatric OSA and underscore the need for early screening and prevention of OSA among children with those risk factors.