Who is becoming overweight during the elementary school years?

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.

Rapid increase in the prevalence of obesity in elementary school children

OBJECTIVE

Three critical periods have been suggested for the development of obesity during childhood: fetal, ages 4-6 y, and adolescence. The prevalence of obesity in elementary school children is increasing in Japan, and the present study examines whether this rising prevalence occurs during the elementary school period (age 6-11 y) or is occurring prior to entry into elementary school.

DESIGN

Repeated cross-sectional sampling of cohorts of children for the prevalence of obesity.

SETTING AND PARTICIPANTS

The data from 81 264 first grade and 87 849 seventh grade children (94 and 87% of the total populations, respectively) between 1989 and 2002 in Kagoshima City were analyzed. Data were also obtained from nationwide surveys published by the Ministry of Japan between 1989 and 2001.

MEASUREMENTS

Obesity was defined by the body mass index for an age- and sex-specific 95th percentile cutoff point in Japanese children. Trends in obesity and odds ratios of the prevalence of obesity were also determined.

RESULTS

The period 1989-2001/2 showed significant increases in the prevalence of obesity for both genders, in both first and seventh grades, and in both Kagoshima City and nationwide. The odds ratios for the prevalence of obesity of 12-y-old children calculated against the prevalence of obesity within the same cohort at 6 y old revealed that a significant risk for development of obesity during the elementary school years applied only to boys from around 1993 onward in Kagoshima City and applied throughout the study period in nationwide Japan.

CONCLUSION

Obesity prevalence increases for boys during elementary school years but does not significantly increase for girls. A rising trend for becoming obese before starting elementary school was present for both boys and girls over the period 1989-2001. Educational programs to improve nutrition and physical activity, especially for boys, are becoming increasingly necessary.

Prevention of mildly overweight children from development of more overweight condition

BACKGROUND

A follow-up study has reported that not only highly obese but also mildly obese children are becoming heavier during the elementary school children. Then we determined the effect of programs for the screening and treatment of overweight elementary school children whether the programs prevented mildly overweight children from development of more overweight condition.

METHODS

Subjects were 40 overweight children who participated in both screening and treatment programs. As controls, only 240 children who participated in the screening program were used. The mean observation periods of the subjects and controls were 14 and 12 months, respectively.

RESULTS

In both groups, older and heavier children significantly decreased their indices of overweight (percent relative body weight; %RBW), indicating that mildly obese children worsened their %RBW. However, the incidence of children who worsened their %RBW was significantly lower in the subjects (5 of 40) than in the controls (133 of 240) (P < 0.0001). Finally, the subjects significantly reduced their mean %RBW (P < 0.0001) and the controls significantly worsened it (P = 0.0093).

CONCLUSION

The treatment program was found important because it prevents mildly overweight children who may worsen their overweight indices without the program from developing more overweight condition.