Child-related and parental predictors for thelarche in a general population of girls: the PANIC study.

BACKGROUND: Obesity has been associated with earlier thelarche, whereas other predictors for it remain unclear. METHODS: We studied child-related and parental predictors for earlier thelarche in 195 girls aged 6-8 years followed up for 2 years. A physician evaluated breast development by inspection and palpation. Body fat percentage (BF%) was measured by dual-energy X-ray absorptiometry, diet by food records, and physical activity and sedentary time by body movement and heart rate monitors. Parental education, smoking, and alcohol consumption and household income were assessed by questionnaires. Gestational age, birth weight, and maternal prepregnancy BMI were obtained from hospital registers. Predictors for thelarche were examined using logistic regression analysis adjusted for age and follow-up time. RESULTS: The incidence of thelarche during 2 years increased by 11% (OR 1.11, CI 1.06-1.17, p < 0.001) for 1 unit increase in baseline BF%. Girls with a smoking parent had a 2.64 (95% CI 1.21-5.77, p = 0.015) times higher incidence of thelarche than other girls. The associations of lower parental education and higher maternal prepregnancy BMI with the higher incidence of thelarche were largely explained by BF%. Other possible predictors were not associated with thelarche. CONCLUSIONS: Higher BF% and exposure to tobacco smoke are independent predictors for earlier thelarche.

Determinants of Cognitive Performance in Children and Adolescents: A Populational Longitudinal Study.

We evaluated the determinants of cognitive performance in children and adolescents. This is a longitudinal study, secondary analysis of the Physical Activity and Nutrition in Children (PANIC) study. We assessed 502 children (51.6% girls) at middle childhood (range: 6.6 to 9.0 years), at late childhood, 437 children (51.0% girls, range: 8.8 to 11.2 years), and in 277 adolescents (54.5% girls, range: 15.0 to 17.4 years). Raven's progressive matrices tests estimated the participants' cognitive performance (outcome variable) at all time points. In total, we evaluated 29 factors from various dimensions (prenatal, neonatal, child fitness, lifestyle and anthropometrics). None of the neonatal and anthropometric parameters were associated with cognitive performance. Preeclampsia (prenatal) and listening to music, writing, arts and craft and watching TV (lifestyle) were negatively associated with cognitive performance. Shuttle run and box and block tests (fitness), and playing music, reading and time at the computer (lifestyle) were positive determinants of cognitive performance in children and adolescents. Fitness and lifestyle factors during childhood and adolescence diminished the importance of prenatal factors on cognitive performance and lifestyle factors were especially relevant in regard to cognitive performance. Reading was positively associated with cognitive performance, regardless of age and time dedicated, and should be promoted.