The Study
Association between shift work and insulin resistance in women: Implications for metabolic health
This study found that women who work nights or odd hours are more likely to have higher insulin resistance than those who work regular days — but it doesn’t prove that shift work causes it. It could be because of other things like diet, sleep, or stress.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Women who work nights or irregular hours have a harder time regulating blood sugar, especially if they're older, overweight, or used to smoke.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — these increases are large enough to significantly raise diabetes risk in real life, especially for vulnerable groups.
- 2Shift workers: 30% higher risk (OR 1.30); women 40–49: 88% higher risk (OR 1.88); overweight shift workers: 79% higher risk (OR 1.79); former smoker shift workers: 158% higher risk (OR 2.58); pink-collar shift workers: 37% higher risk (OR 1.37).
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
PLOS One
Year
2025
Authors
You-Jung Choi, Soo Hyeon Cho, Ja-Ho Leigh, Sung Hoon Jeong
Related Content
Claims (6)
Working irregular hours or not sleeping well can mess up your body’s internal clock, which in turn hurts your metabolism and liver — making it harder for your body to process food and stay healthy.
Korean women in their 40s who work nights or irregular shifts are almost twice as likely to have high insulin resistance — a sign their body isn’t using sugar properly — compared to those who work regular daytime hours.
Women in Korea who work non-traditional hours like nights or rotating shifts are 30% more likely to have higher insulin resistance — a sign their body isn’t using sugar properly — even when you account for their weight, diet, and income, which might mean their work schedule is hurting their metabolism.
Women who work evening or night shifts in service jobs like retail or nursing are more likely to have higher insulin resistance — a sign their body isn’t using sugar properly — than women in the same jobs who work regular daytime hours.
Korean women who are overweight and work nights or rotating shifts are much more likely to have high insulin levels than overweight women who work regular daytime hours, which might mean their bodies have a harder time managing blood sugar.
Doctors can use a simple calculation from two common blood tests — triglycerides and glucose — to tell if Korean women of working age might have insulin resistance, and if the number is above 8.35, it means they’re at higher risk.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.