Essential Metals Zinc, Selenium, and Strontium Protect against Chromosome Damage Caused by Polycyclic Aromatic Hydrocarbons Exposure

Essential metals play important roles in maintaining cellular homeostasis, but the effects of their interaction with the environmental pollutants are still not very well-known in human subjects. The aim of this study was to evaluate the roles of essential metals and their interactions with polycyclic aromatic hydrocarbons (PAHs) on chromosome damage, an early carcinogenic event. A total of 1245 male workers were included in this study and the levels of 11 urinary essential metals, 12 urinary PAH metabolites, plasma concentrations of benzo­[a]­pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts, and lymphocyte micronucleus (MN) frequencies were monitored. We found that zinc (Zn), selenium (Se), and strontium (Sr) have significant inverse dose–response relationships with MN frequencies (all <i>P</i> < 0.05). Furthermore, the protective roles of Zn, Se, and Sr were mainly shown among subjects with high levels of BPDE-Alb adducts. Significant effect modification of BPDE-Alb adducts on the associations of Zn, Se, and Sr with MN frequencies was observed (all <i>P</i>_interaction < 0.05). Our study showed evidence that Zn, Se, and Sr play protective roles in reducing chromosome damage, and these effects can be modified by PAH exposure levels. These findings add potential evidence for the preventive effects of Zn, Se, and Sr against carcinogenesis in human subjects

Association of shift-work, daytime napping, and nighttime sleep with cancer incidence and cancer-caused mortality in Dongfeng-tongji cohort study

<p><b>Background:</b> Few studies investigated the combined effects of night-shift work, daytime napping, and nighttime sleep on cancer incidence and mortality.</p> <p><b>Methods:</b> A total of 25,377 participants were included in this study. Information on sleep habits, cancer incidences, and mortalities were collected. Cox proportional hazards models were used to calculate the adjusted hazard ratios and 95% confidence intervals (HRs, 95%CIs).</p> <p><b>Results:</b> Male subjects experienced ≥20 years of night-shift work, or without daytime napping had an increased risk of cancer, when compared with males who did not have night-shift work or napped for 1–30 min [HR (95%CI) = 1.27 (1.01–1.59) and 2.03 (1.01–4.13), respectively]. Nighttime sleep for ≥10 h was associated with a separate 40% and 59% increased risk of cancer [HR (95%CI) = 1.40 (1.04–1.88)] and cancer-caused mortality [HR (95%CI) = 1.59 (1.01–2.49)] than sleep for 7–8 h/night. Combined effects of three sleep habits were further identified. Male participants with at least two above risk sleep habits had a 43% increased risk of cancer [HR (95%CI) = 1.43 (1.07–2.01)] and a 2.07-fold increased cancer-caused mortality [HR (95%CI) = 2.07 (1.25–3.29)] than those who did not have any above risk sleep habits. However, no significant associations were observed among women.</p> <p><b>Conclusions:</b> Long night-shift work history, without daytime napping, and long nighttime sleep duration were independently and jointly associated with higher cancer incidence among males.KEY MESSAGES</p><p>Night-shift work of ≥20 years, without napping, and nighttime sleep of ≥10 h were associated with increased cancer incidence.</p><p>Nighttime sleep ≥10 h was associated with a 2.07-fold increased cancer-caused mortality among males.</p><p>Combined effects of night-shift work ≥20 years, without napping, and nighttime sleep ≥10 h on increasing cancer incidence were existed among males.</p><p></p> <p>Night-shift work of ≥20 years, without napping, and nighttime sleep of ≥10 h were associated with increased cancer incidence.</p> <p>Nighttime sleep ≥10 h was associated with a 2.07-fold increased cancer-caused mortality among males.</p> <p>Combined effects of night-shift work ≥20 years, without napping, and nighttime sleep ≥10 h on increasing cancer incidence were existed among males.</p