Osteocalcin and Parental Perceptions. Childhood osteocalcin and its association to early growth, body composition and neurodevelopment along with parental perceptions on childhood overweight and obesity

Abstract

Background and aims: Early programming mean that environmental factors, hormonal levels and early life experiences, like feeding practices, during the first years of life, may have long-lasting effects on later health. One hormone with programming potential is osteocalcin. Early osteocalcin levels might impact later growth, body composition and cognition, but little is known about this hormones’ actions and levels during childhood. In adults, low osteocalcin levels are associated to a high body mass index (BMI) and lower cognition. Given that childhood obesity is an increasing public health problem, knowledge of pathophysiology needs to improve, but also knowledge about barriers and facilitators in effective weight treatment. The aim of this thesis was to explore parental perceptions of child weight status, and to increase knowledge about osteocalcin and its potential association to early growth and neurodevelopment.

Methods: This study is based on two longitudinal birth cohorts from Halland, Sweden. The first, which started in 2007, included 2,666 children, monitored with anthropometric data and questionnaires until five years of age (y). The second included 551 children, born 2008-2012 who attended similar follow ups, but with additional regular blood sampling for 5 years. Of the 551 children, 224 underwent dual energy x-ray absorptiometry (DXA) at age 8 for body composition assessment, and 158 children underwent neurocognitive testing at age 4.

Results: In total, 96.4% respective. 87.1% of parents of two- and five-year-old children with overweight or obesity perceived their child’s weight to be just about right. Reference limits for total serum osteocalcin were established. Age and sex differences were found and the levels correlated to feeding practices, and gestational age. Serum levels of osteocalcin correlated to growth and body composition in a negative way during infancy, but in a positive way during childhood. Osteocalcin at five years of age correlated positively to fat mass index for girls at age eight and to fat-free mass index for boys at age eight. Osteocalcin at four months of age correlated to full-scale intelligence quotient and motor development at four years of age.

Conclusions: Early osteocalcin levels carry information about future growth, body composition and neurodevelopment and may therefore be of importance within the concept of early programming. Osteocalcin shows age and sex-related differences that may be of importance in the development of childhood obesity. The low agreement between parental perceptions of child weight and actual child weight status may be another factor that impacts the development and treatment of childhood obesity.