Effects of rotating shift work on biomarkers of metabolic syndrome and inflammation.

SOOKOIAN S; GEMMA C; FERNANDEZ GIANOTTI T; BURGUEÑO A; ALVAREZ A; GONZALEZ C; PIROLA, CJ

JOURNAL OF INTERNAL MEDICINE

Blackwell Scientific Publication

Lugar: London, UK; Año: 2007 vol. 261 p. 285 - 292

0954-6820

Objectives: serotonin is a neurotransmitter associated with circadian rhythm regulation, thus explored a possible relation among serotonin (5-HT), serotonin metabolite 5-hydroxyindolacetic acid (5-HIAA), and the functional polymorphism of serotonin transporter gene (SLC6A4) promoter with rotating shift work. Participants: 683 men were included in this study: 437 day-workers were compared with 246 rotating shift-workers. Results: Platelet 5-HT content differed significantly (p<0.002) between day-workers (41.28±1.99 pg/mg) and workers (37.91±4.16 pg/mg). Accordingly, 5-HIAA content was also significantly (p<0.00004) higher in day-workers (11.40±0.82 pg/mg) in comparison with shift-workers (9.33±1.02 pg/mg). We looked for further differences in SLC6A4 promoter (5-HTTLPR, 44 bp insertion: long (L)/deletion: short (S) alleles). We found a significant (p< 0.02) difference in genotype distribution between day-workers (LL: 126, LS: 202, and SS: 109 individuals) and shift-workers (LL: 47, LS: 124 and SS: 75 individuals). When we divided the subjects between workers with less and more than 60 month rotating shift work exposure, the difference in SLC6A4 genotypes frequency was only significant in the group with more than 60 months (p<0.003). Logistic regression analysis showed that shift work was associated with S allele independently of work time exposure (Estimate±SE: 0.27±0.11, p<0.015). Besides, there was a significantly lower content of platelet 5-HIAA in S allele carriers in comparison with the other genotypes (SS: 9.2±1.0 pg/mg vs. SL/LL: 11.0±0.8 pg/mg, p<0.02). In conclusion, platelet 5-HT and 5-HIAA contents were significantly lower in rotating shift-workers in comparison with day-workers and there was a significant association between the S variant of SLC6A4 promoter and shift work.