Sedentary Behavior is Associated with Increased Risk of Obesity in Adolescents

by | Sep 29, 2020 | 2019, Infant and Children's Health, Obesity

Written by Angeline A. De Leon, Staff Writer. This study found that, of the adolescents in lower- and middle-income countries (LMICs), rates of obesity and sedentary behavior (SB) were highest among those in the higher-income countries, whereas the relationship between obesity and SB was strongest adolescents in the lowest-income countries.

infant and children's health - cell phone useOver the last several decades, rates of obesity in developed countries have seen a steep rise, with lower-income countries witnessing an even greater increase, even among preschoolers 1. In developing countries, for example, up to 65% of adolescents have been classified as obese 1. The correlation between childhood obesity and obesity in adulthood is high, warranting the need to effectively address and manage obesity during the critical time period of adolescence 2. Research has identified sedentary behavior (SB), defined as any waking activity characterized by an energy expenditure ≤ 1.5 metabolic equivalents (e.g., time spent in front of the computer, driving, reading, etc.), as a key risk factor for weight gain 3. SB appears to be strongly linked to other factors known to increase risk of obesity (snacking, low physical activity, high levels of abdominal fat) 4,5 and research suggests that, irrespective of physical activity levels, higher SB seems to be related to higher plasma glucose levels and cholesterol 6. Research findings in this regard are limited, however, by the fact that the association between SB and weight has primarily been studied only in developed, high-income countries 3. New evidence showing that country income level and family income level may factor into the prevalence of obesity and different types of SB 7,8 also suggests the need to explore the association between SB and obesity in developing areas. To this end, researchers at King’s College London conducted a cross-sectional study 9 looking at the link between SB and obesity among adolescents in lower- and middle-income countries (LMICs).

A total of 116,762 LMIC students (aged 12-15 years, 48.6% female) from around the world were assessed for obesity (defined as more than 2 standard deviations above the median weight for age and sex) based on body mass index (BMI). SB was evaluated based on the question, “how much time do you spend during a typical or usual day sitting and watching television, playing computer games, talking with friends, or doing other sitting activities?”, with responses varying from less than 1 hour to greater than 8 hours and excluding time spent at school or studying. Odds ratios (ORs) were computed, controlling for age, sex, food insecurity, physical activity, and fruit/vegetable intake.

Analyses revealed an overall prevalence of 4.0% for obesity and an overall prevalence of 26.2% for an SB of 3 hours per day or greater. Rates of obesity and SB appeared to be highest in upper-middle-income countries (Malaysia, Libya, Peru) and lowest in low-income countries (Afghanistan, Cambodia, Myanmar). An SB of 3 hours per day or greater was associated with higher risk of obesity in 32 of 41 countries tested, and this association was strongest for low-income countries (pooled OR = 1.87, 95% Confidence Interval: 1.08 to 3.25), followed by lower-middle-income countries (OR = 1.28, 95% CI: 1.17 to 1.41), and finally upper-middle-income countries (OR = 1.08, 95% CI: 0.99 to 1.18) (between-group heterogeneity significant at p = 0.008).

Evidence from the current study indicates that sedentary behavior for periods of 3 hours or longer each day is associated with increased risk of obesity among adolescents. Interestingly, researchers found that while the prevalence of obesity and SB were highest among higher-income countries, the association between obesity and SB was strongest among low-income countries. This suggests the need to consider different approaches to managing obesity based on the socioeconomic landscape of a given country. Given the cross-sectional nature of the present study, future studies are needed to determine the direction of the relationship between SB and obesity (whether obesity causes SB or SB causes obesity). Other limitations of the current study relate to the use of a self-report measure to assess SB and the failure to control for potential confounding factors such as depression.

Source: Ashdown-Franks G, Vancampfort D, Firth J, et al. Leisure-time sedentary behavior and obesity among 116,762 adolescents aged 12-15 years from 41 low- and middle-income countries. Obesity. 2019; 27(5): 830-836. DOI: 10.1002/oby.22424.

© 2019 The Obesity Society

Posted September 29, 2020.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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