• Weaning: Risk factors for the development of overweight and obesity in childhood - a systematic review

      Fallows, Stephen; Kendall, Rebecca (University of Chester, 2011-09-08)
      Weaning practices including the age of the infant at time of weaning, nutritional composition of the weaning diet and rapid weight gain have been suggested to be risk factors for overweight and obesity in childhood. The purpose of this review was to investigate the relationship between weaning practices and overweight and obesity in childhood (from birth to 18yrs) and to identify the risk factors associated with weaning for overweight and obesity in childhood (birth to 18yrs). This was achieved through a systematic review of relevant literature, identified using a number of databases such as CINAHL, EMBASE, and MEDLINE and through searching individual journals. Inclusion criteria consisted of children’s age 0-18yrs, details on stage of and weaning diet, studies published in English from 2000-2010 and human studies. The quality of the methodology of studies was assessed using the Downs & Black (1998) quality assessment tool. Thirteen studies out of an original 67 were included in the review. Study sizes varied from 90 to 10,553 subjects and quality assessment scores ranged from 14 to 23. All of the studies which considered the relationship between age at introduction of complementary foods and weight gain found those infants weaned before 16 weeks (wks) gained more weight than those weaned later; these findings were more significant in those infants who were not breastfed or breastfed for less than 4wks. One study (from 5) found a significant relationship between the age at introduction of complementary foods and overweight and obesity. Four studies (from 5) reported a significant relationship between nutritional composition of the weaning diet during the first year of life and overweight; the most significant effect being that of protein as a percentage of energy intake. The evidence for the impact of early weaning on adiposity levels, overweight and/ or obesity remains is inconsistent. Findings suggest that there is no relationship between adiposity and BMI in childhood with early weaning practices. However, the introduction of complementary foods before 16wks was shown to lead to greater weight gain in early childhood (independent of other confounding factors), especially in those infants who are fed formula food or is only breastfed for less than 4wks, which in turn could lead to overweight and obesity in later childhood. High protein intake (as percentage of energy) is strongly suggested to influence weight gain during infancy and BMI in early childhood.