Longitudinal changes in body composition and waist circumference by self-reported levels of physical activity in leisure among adolescents: the Tromsø study, Fit Futures

Association between neighborhood health behaviors and body mass index in Northern Norway: evidence from the Tromsø Study

AIM

The prevalence of overweight and obesity has risen rapidly worldwide, and the ongoing obesity pandemic is one of the most severe public health concerns in modern society. The average body mass index (BMI) of people living in Northern Norway has also steadily increased since the late 1970s. This study aimed to understand how individuals' health behavior is associated with the general health behavior of the people in their neighborhood.

METHODS

Using the population-based Tromsø Study, we examined the life course association between average leisure time physical activity at the neighborhood level and the BMI of individuals living in the same neighborhood. We used a longitudinal dataset following 25,604 individuals living in 33 neighborhoods and performed a linear mixed-effects analysis.

RESULTS

The results showed that participants living in neighborhoods whose residents were more physically active during their leisure time, were likely to have a significantly lower BMI (-0.9 kg/m², 95% CI -1.5 to -0.4). Also, individuals living in neighborhoods whose residents were doing mainly manual work, had significantly higher BMIs (0.7 kg/m², 95% CI 0.4-1.0).

CONCLUSIONS

Our results showed a strong association between the average leisure time physical activity level of neighborhood residents and the higher BMI levels of residents of the same neighborhood.

Common social determinants for overweight and obesity, and dental caries among adolescents in Northern Norway: a cross-sectional study from the Tromsø Study Fit Futures cohort

BACKGROUND

Non-communicable general and oral health conditions share common risk factors. Studies investigating common social determinants as risk factors for overweight/obesity and dental caries among the same adolescents are scarce and inconclusive.

METHODS

This cross-sectional study included data from 464 girls and 494 boys from the population-based Tromsø study Fit Futures, which included first-year students attending upper secondary school in 2010-2011 from two municipalities in Northern Norway (1038 participants in total, 93% participation rate). Multivariable binary logistic regression analyses stratified by sex were used to investigate the association between socioeconomic position indicators (adolescent's own study program, parents' education and employment status) and overweight/obesity indicated by body weight and waist circumference, untreated dental caries in dentine, and when these conditions were considered simultaneously.

RESULTS

Boys enrolled in the general studies and sports programs (versus vocational) had lower odds of being overweight/obese (POR 0.42, 95% CI 0.20-0.86 and POR 0.24, 95% CI 0.08-0.73, respectively), of having high waist circumference (POR 0.39, 95% CI 0.21-0.75 and POR 0.25, 95% CI 0.10-0.64, respectively), dental caries (POR 0.57, 95% CI 0.32-0.99 and POR 0.47, 95% CI 0.22-0.98, respectively), and being simultaneously overweight/obese, having high waist circumference and dental caries (POR 0.24, 95% CI 0.07-0.81 and POR 0.11, 95% CI 0.01-0.98, respectively). Girls enrolled in the general studies program (versus vocational) had lower odds of having dental caries (POR 0.50, 95% CI 0.30-0.84).

CONCLUSIONS

Adolescent's own study program was identified to be a common social determinant for overweight/obesity and dental caries among boys. These results support the broader concept of social determinants as common risk factors for general and oral health conditions, and call for common health promotion strategies addressing these common social determinants among adolescents. However, there is a need for more studies to investigate and better understand the influence of social determinants on health conditions among adolescents.

Association between objectively measured physical activity and longitudinal changes in body composition in adolescents: the Tromsø study fit futures cohort

OBJECTIVES

Physical activity may be important in deterring the obesity epidemic. This study aimed to determine whether objectively measured physical activity in first year of upper secondary high school predicted changes in body composition over 2 years of follow-up in a cohort of Norwegian adolescents (n=431).

DESIGN

A longitudinal study of adolescents (mean age of 16 (SD 0.4) at baseline, 60.3% girls) participating in the Fit Futures studies 1 (2010-2011) and 2 (2012-2013).

SETTING

All eight upper secondary high schools in two municipalities in Northern Norway.

PARTICIPANTS

Students participating in both studies and under the age of 18 at baseline and with valid measurement of physical activity at baseline and body composition in both surveys.

PRIMARY AND SECONDARY OUTCOMES

Change in objectively measured body mass index and waist circumference and change in dual-energy X-ray absorptiometry measured fat mass index, lean mass index (LMI) and appendicular LMI (aLMI) between baseline and follow-up.

RESULTS

At baseline, boys had significantly higher physical activity volume (p=0.01) and spent on average of 6.4 (95% CI 2.1 to 10.6) more minutes in moderate-to-vigorous physical activity (MVPA) than girls (p<0.01). In girls, multivariate regression analyses showed that more sedentary time was negatively associated with changes in LMI (p<0.01) and aLMI (p<0.05), whereas more light activity had opposite effects on these measures (p<0.01 and p<0.05, respectively). No significant associations between measures of baseline physical activity and changes in body composition parameters were observed in boys.

CONCLUSIONS

In this cohort of Norwegian adolescents, sedentary and light physical activity was associated with changes in LMI and aLMI in girls, but not boys. Minutes spent in MVPA in first year of upper secondary high school was not associated with changes in measures of body composition in neither sex after 2 years.