Home Health & Wellness Study Shows Social Jetlag Trajectories Linked to Obesity in Young Adults

Study Shows Social Jetlag Trajectories Linked to Obesity in Young Adults

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Researchers have found significant associations between social jetlag trajectories and body mass index (BMI) in young adults, highlighting the potential long-term health risks posed by disrupted sleep patterns during adolescence. The study, published in the journal Sleep, offers crucial insights into how variations in sleep schedules from ages 11–22 can impact weight status at age 23, with notable differences observed between males and females.

The study utilised data from two longitudinal studies conducted in Taiwan, involving 4,287 participants. Social jetlag was defined as a difference of at least two hours between the sleep midpoints of weekdays and weekends. BMI was calculated based on self-reported height and weight, categorising participants as underweight, normal weight, overweight, or obese. Group-based trajectory modelling and multinomial logistic regression were used to look at the data and find patterns in social jetlag and how they were linked to BMI.

4 Distinct social jetlag trajectories

The study identified four distinct social jetlag trajectories: low-stable, moderate-decreasing, low-increasing, and chronic. These trajectories describe the variations in the participants’ sleep schedules over time:

  1. Low-stable (42%). Participants with minimal differences in sleep timing between weekdays and weekends.
  2. Moderate-decreasing (19%). Those who started with moderate social jetlag but experienced a decrease over time.
  3. Low-increasing (22%). Participants with initially low social jetlag that increased during adolescence, peaking around age 18.
  4. Chronic (17%). Individuals with consistently high social jetlag throughout the study period.

Associations with BMI

The study revealed significant associations between social jetlag trajectories and BMI, with varying impacts observed based on sex. Among males, those with a low-increasing trajectory had a higher risk of being underweight (adjusted odds ratio [aOR], 1.96) or obese (aOR, 1.40) compared to those with a low-stable trajectory. For females, a low-increasing trajectory increased the risk of obesity (aOR, 1.61), and a chronic trajectory further amplified this risk (aOR, 2.04).

Sex differences and potential explanations

The observed sex differences in the impact of social jetlag on BMI suggest that males and females may respond differently to disrupted sleep patterns. Males with increasing social jetlag were more likely to be underweight, a finding that may be linked to variations in substance use, such as smoking, which has differing effects on weight. Conversely, females with increasing or chronic social jetlag were more susceptible to obesity, potentially due to greater sensitivity to circadian rhythm disruptions.

Clinical implications

The findings underline the importance of addressing social jetlag during adolescence to prevent unhealthy weight outcomes in young adulthood. Health practitioners should consider sex differences when developing interventions and offer tailored guidance to manage sleep schedules effectively. Emphasising consistent sleep patterns and addressing circadian misalignment could play a critical role in weight management strategies for young adults.

The study’s strengths include its longitudinal design, large sample size, and detailed analysis of sleep patterns over an extended period. However, the reliance on self-reported data for BMI and sleep timing introduces potential biases, and the findings may not be generalisable beyond the Taiwanese population. Future research should incorporate objective measures of sleep and body composition to validate and expand upon these findings.

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