Determinants of weight gain in children from 7 to 10 years.

BACKGROUND AND AIM: To determine the influence of the family risk factors (parental weight, socioeconomic status and cultural level) on the distribution of overweight or obesity in prepubertal children and the dynamics of their weight gain.

METHODS AND RESULTS: Three hundred forty-one children (183 boys) attending the second grade of primary school (age 7.4+/-0.5 years) were enrolled in a longitudinal study in Southern Italy. Overweight and obesity status were defined by a body mass index (BMI) above the percentile having respectively the value of 25 and 30 kg/m(2) at 18 years, according to national reference data; overweight extent was expressed as BMI standard deviation score (BMI-SDS). Information about BMI and socioeconomic conditions (occupation and educational level) of parents were collected. Distribution of overweight and obese schoolchildren and variations of BMI-SDS were evaluated over a 3-year period; relationships with family risk factors were also sought. The distribution of overweight/obese children at baseline was high (40%). Tracking rates of overweight and obesity were 73% and 80%, respectively. The higher the BMI-SDS at 7 years, the higher the BMI-SDS at 10 years (r 0.86, P=0.0001). The highest BMI value and the highest distribution of overweight/obese children were observed in subjects with the highest amount of family risk factors. Children exhibiting accelerated weight gain (delta BM I>1/year) showed higher male/female ratio, higher baseline BMI values, higher maternal BMI values, lower maternal educational level and a dramatic increase in the percentage of overweight/obese children than children with normal weight gain.

CONCLUSIONS: Children who are overweight/obese at 7 years tend to maintain this condition during prepubertal age. Paediatricians should be alerted when dealing with a child showing a BMI increase above than 1U/year during primary school. Targeted intervention should be directed at young children with overweight parents and low socio-cultural level.