| dc.description.abstract | Background:
The burden of disease in children and adolescents has moved from infections to noncommunicable diseases, including overweight and obesity (OWOB). Long-term successful treatment has been limited, and prevention strategies seem to be a more appropriate method. Health-related habits, especially during adolescence, have been found to strongly correspond to habits and health in adulthood. To enable the development of high-quality prevention strategies, a proper start is to become familiar with the prevalence and risk factors for OWOB in a targeted population. The aim of this thesis was to study the prevalence of OWOB in 15–16-year-old adolescents and to examine risk factors for OWOB in children and adolescents in Oppland County.
Material and methods:
The data were collected in Oppland County and consisted of two datasets. One dataset was collected during visits to the local health nurse as routine check-ups. The parental questionnaire was collected at the child`s routine-control performed at six years of age. In the following routine control at eight years of age, the nurse measured height and weight. Thus, we included data from 951 (47%) children born in 2001. The other dataset contained data from a repeated cross-sectional study of all 10th grade students (15–16 years of age) in Oppland County in 2002 and 2017. Questionnaire-data were available from 1675 (80%) adolescents in 2002 and from 1580 (71%) in 2017. It contained questions regarding weight, height, health-related habits, subjective social status (SSS), and mental health problems through the Strength and Difficulties Questionnaire (SDQ). The dataset from 2002 was collected by the Norwegian Institute of Public Health, and the dataset from 2017 was collected by our research team. In Paper I, we explored the prevalence of OWOB and the association between breastfeeding history in infancy and body mass index (BMI) in eight-year-old children through linear and logistic regression. In Paper II we compared BMI, BMI z-scores, BMI distributions, and prevalence of OWOB in the adolescents in 2002 and 2017 stratified by gender. In Paper III we investigated the association between SDQ scores and both BMI and OWOB through linear and logistic regression analyses. We also analyzed whether the associations between mental health problems and BMI were different for boys and girls. In Paper IV, we built a structural equation model to explore whether the association between Subjective sociodemographic status (SSS) and BMI was mediated by unhealthy behaviors.
Results:
In Paper I, we did not reveal any associations between breastfeeding history in infancy and BMI or OWOB in eight-year-old children when adjusted for relevant confounders. In Paper II, we found that for adolescent girls, the mean BMI and the prevalence of OWOB significantly increased in the dataset from 2017 compared to the dataset from 2002. The mean differences in BMI z-scores were also positive across the 5th to the 95th percentile, indicating that the BMI values increased across the entire distribution. No such changes were found for boys. In Paper III, we found an association between reporting more peer problems and increased BMI and also increased risk of OWOB when analyzing data from boys and girls together. Additionally, we also found gender-related differences in the association between increased SDQ sub-scores and both increased BMI, and risk of OWOB. In Paper IV, we did not find an association between SSS and BMI in the 2002 dataset. In the 2017 dataset, we found that the significant association between increased SSS and lower BMI was mediated by hours of leisure-time exercise and through a latent variable consisting of habits related to cigarette smoking, snuff use and alcohol drinking.
Conclusion and clinical implications:
We did not reveal that breastfeeding history in infancy was associated with OWOB in eight-year old children. We found gender-related differences regarding prevalence and risk factors for OWOB when assessing the 15–16-year-old adolescent population of Oppland County at two separate time points 15 years apart. We related and interpreted the finding of no association in 2002, but an association between higher SSS and lower BMI in 2017, to societal changes through the epidemiological transition in the years between the surveys. The health-related behaviors that mediated this association in our study were multifaceted and included several risk factors, such as cigarette smoking, snuff use and alcohol drinking, in addition to exercise. No single risk factor can be identified and eliminated to reduce the prevalence of OWOB. The risk factors of adolescent OWOB should therefore be interpreted within the behavioral and sociodemographic context of adolescents. | en_US |
