The association between metabolic parameters and evening chronotype and social jetlag in non-shift workers: A meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 36479212 · doi:10.3389/fendo.2022.1008820
What was done
A systematic review and meta-analysis of searches across MEDLINE, EMBASE, and Cochrane Reviews (through February 2022) evaluating the association of evening chronotype and social jetlag (SJL) with metabolic parameters (obesity, blood glucose, and lipid markers) in non-shift working adults. Summary effects were calculated as weighted mean differences (WMDs) with 95% confidence intervals across 27 included studies.
What was found
Compared with morning chronotypes, individuals with an evening chronotype had: - Higher BMI: WMD = 0.44 kg/m² (95% CI, 0.30 to 0.57 kg/m²; p < 0.001) - Higher fasting blood glucose: WMD = 5.83 mg/dL (95% CI, 3.27 to 8.38 mg/dL; p < 0.001) - Higher total cholesterol: WMD = 6.63 mg/dL (95% CI, 0.69 to 12.56 mg/dL; p = 0.03) - Lower HDL cholesterol: WMD = -1.80 mg/dL (95% CI, -2.30 to -1.31 mg/dL; p < 0.001) Comparing individuals with large versus small social jetlag: - Larger waist circumference: WMD = 0.80 cm (95% CI, 0.77 to 0.83 cm; p < 0.001)
Why it matters
This review consolidates evidence that circadian misalignment (evening chronotype and social jetlag) is linked to unfavorable glucose and lipid profiles in non-shift working adults, showing that these metabolic risks extend beyond formal shift work.
Limits
The abstract does not report the total participant count, individual study designs (e.g., cross-sectional vs. prospective cohort), or specific definitions for large versus small social jetlag. Because the underlying evidence is observational, causality cannot be established, and residual confounding by diet, physical activity, or sleep duration cannot be ruled out. Additionally, several observed effect sizes (such as BMI difference of 0.44 kg/m² and waist circumference difference of 0.80 cm) are clinically modest.
Cited by
- supports Evening chronotypes who do not sleep according to their circadian preference have higher C-reactive protein, poorer HbA1c control, and higher obesity rates.