Psychological factors and weight problems in adolescents. The role of eating problems, emotional problems, and personality traits: the Young-HUNT study

BACKGROUND

The associations between psychological factors and weight problems in adolescents are not conclusive. We studied associations between psychological factors, including personality and weight problems, in an adolescent population. In addition, we examined the same psychological factors as predictors for change in weight categories during adolescence.

METHOD

From 1995 to 1997, 8,090 adolescents, aged 13-18 years, participated in the Young-HUNT-I study; of those, 1,619 also participated in a follow-up study in 2000-2001. They completed a questionnaire monitoring eating problems, self-esteem, personality, anxiety, and depression, and had their height and weight measured. Weight problems were defined using the international age-and sex-specific BMI-cut-offs defining underweight, overweight, and obesity. Psychological factors at baseline were studied both in relation to weight categories at baseline, and as predictors for weight change between baseline and the follow-up.

RESULTS

Significant sex differences in mean values were found in all psychological factors, with higher scores in girls compared with boys. In the cross-sectional design, eating problems were associated with weight problems, and the two factors of oral control (EAT-A) and food preoccupation (EAT-B) showed an inverse association. Oral control was associated with underweight, while food preoccupation was associated with overweight and obesity in both sexes. Low self-esteem was associated with overweight and obesity in both sexes, but no association was found between emotional problems or personality traits, and weight problems. During the follow-up, oral control was a clear predictor of weight change during adolescence in both sexes. Oral control protected against unhealthy weight gain but also predicted unhealthy weight reduction in both sexes.

CONCLUSIONS

Girls scored higher on all psychological factors compared with boys, but no sex differences were found with regard to the association between psychological factors and weight problems. Eating problems showed the strongest association with weight problems at baseline and were also the strongest predictor of weight change during adolescence.

Sex differences in time trends for overweight and obesity in adolescents: the Young-HUNT study

AIMS

To investigate sex differences in the prevalence and extent of overweight and obesity in adolescents aged 14-18 years.

METHODS

Standardized measurements of height and weight were collected from surveys of adolescents in the same geographical area in 1966-69 (n = 8378) and in 1995-97 (n = 6673). The prevalence rates of overweight and obesity were calculated using criteria approved by the International Obesity Task Force. The extents of overweight and obesity were assessed by computing age- and sex-specific body mass index (BMI) percentiles.

RESULTS

In 1995-97, 17.2% met the criteria for either overweight or obesity, as compared with 10.7% in 1966-69. The prevalence of overweight and obesity combined was higher in girls (13.0%) than in boys (8.5%) in 1966-69 (difference 4.5%, 95% confidence interval (CI) 3.1-5.9), while no sex difference was found in 1995-97 (girls 16.9%, boys 17.5%, difference -0.6, 95% CI -2.3-1.1). The increase in overweight was greater in boys (6.2PP, 95% CI 4.7-7.6) than in girls (1.9PP, 95% CI 0.4-3.5), while the sex difference in increased obesity was smaller (boys 2.8PP, 95% CI 2.1-3.4, girls 2.0PP, 95% CI 1.3-2.6). The increase in extent of overweight and obesity was highest in boys. The values of the 85th percentile and the 95th percentile in boys increased by 1.3 and 3.0 BMI units, respectively. The corresponding increases in girls were 0.7 and 1.7 BMI units.

CONCLUSIONS

A marked sex difference in time trends for both the prevalence and extent of overweight and obesity, with a more pronounced increase in boys than in girls, was demonstrated. This might have implications for preventive strategies.