Night shift work and chronic lymphocytic leukemia in the MCC-Spain case-control study

Area of Science:

• Epidemiology
• Occupational Health
• Hematology

Background:

• Chronic lymphocytic leukemia (CLL) has limited known modifiable risk factors.
• Circadian disruption, including reduced melatonin and altered molecular signaling, is increasingly implicated in lymphoid neoplasms.
• Previous research suggests a link between circadian rhythm alterations and CLL prognosis.

Purpose of the Study:

• To investigate the association between night shift work and the risk of developing chronic lymphocytic leukemia (CLL).
• To explore whether the duration and type of night shift work modify this association.

Main Methods:

• A case-control study involving 321 incident CLL cases and 1728 population-based controls in Spain.
• Face-to-face interviews collected data on sociodemographic factors, medical history, and occupational history, including night shift work.
• Logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI), adjusting for potential confounders.

Main Results:

• Overall night shift work was not significantly associated with CLL (OR = 1.06).
• However, long-term night shift work (over 20 years) showed a positive association with CLL (OR = 1.77).
• This association was more pronounced for long-term rotating night shifts (OR = 2.29) compared to permanent night shifts (OR = 1.16).

Conclusions:

• While overall night shift work did not show a significant link to CLL, long-term exposure, particularly to rotating night shifts, warrants further investigation.
• The findings suggest a potential role for circadian disruption from prolonged rotating night work in CLL development.
• Further research is needed to confirm these associations and elucidate the underlying mechanisms.