Shift work in young adults linked to elevated cortisol levels, increased CV risk

Manenschijn L. J Clin Endocrinol Metab. 2011;doi:10.1210/jc.2011-1551.

Issue: November 2011

Young adults who work the night shift appear to have increased long-term cortisol levels and elevated BMI, which contribute to their heightened risk for CV disorders, results of a recent study suggest.

Researchers collected hair samples from the back of the scalp of 33 shift workers and 89 day workers who worked in the same factory; cortisol levels were extracted from the samples with methanol and measured using an ELISA kit (DRG Instruments). Researchers also measured height, weight and BMI of all participants.

Overall, shift workers were significantly older, washed their hair more frequently and had higher BMI vs. day workers. Shift workers had significantly higher hair cortisol levels (47.32 pg/mg; 95% CI, 38.37-58.21) vs. day workers (29.72 pg/mg; 95% CI, 26.18-33.73).

To examine the relationship between cortisol levels and age, the researchers divided shift and day workers into two subgroups: aged younger than 40 years and aged older than 40 years. Younger shift workers had significantly higher cortisol levels (48.53 pg/mg; 95% CI, 36.56-64.29) vs. younger day workers (26.42 pg/mg; 95% CI, 22.91-30.55). Younger shift workers had a mean BMI of 27.2 (95% CI, 25.5-28.8), which was elevated as compared with a mean BMI of 23.7 in younger day workers (95% CI, 22.8-24.7). Cortisol levels were elevated in normal-weight participants (95% CI, 26.79-36.48), in overweight participants (95% CI, 30.48-42.76) and in obese participants (95% CI, 43.95-84.72), when the total study population was divided into groups based on BMI classification, according to study results.

“Elevated cortisol levels and BMI may contribute to the increased CV risk found in shift workers,” the researchers concluded.

Disclosure: Dr. Manenschijn reports no relevant financial disclosures.

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