Lights At Night

iLib08 - Citavi Blask, David E. (2008): Melatonin, sleep disturbance and cancer risk. In: Sleep medicine reviews. Online verfügbar unter doi:10.1016/j.smrv.2008.07.007. Abstract The pineal hormone melatonin is involved in the circadian regulation and facilitation of sleep, the inhibition of cancer development and growth, and the enhancement of immune function. Individuals, such as night shift workers, who are exposed to light at night on a regular basis experience biological rhythm (i.e., circadian) disruption including circadian phase shifts, nocturnal melatonin suppression, and sleep disturbances. Additionally, these individuals are not only immune suppressed, but they are also at an increased risk of developing a number of different types of cancer. There is a reciprocal interaction and regulation between sleep and the immune system quite independent of melatonin. Sleep disturbances can lead to immune suppression and a shift to the predominance in cancer-stimulatory cytokines. Some studies suggest that a shortened duration of nocturnal sleep is associated with a higher risk of breast cancer development. The relative individual contributions of sleep disturbance, circadian disruption due to light at night exposure, and related impairments of melatonin production and immune function to the initiation and promotion of cancer in high-risk individuals such as night shift workers are unknown. The mutual reinforcement of interacting circadian rhythms of melatonin production, the sleep/wake cycle and immune function may indicate a new role for undisturbed, high quality sleep, and perhaps even more importantly, uninterrupted darkness, as a previously unappreciated endogenous mechanism of cancer prevention. Kakizaki, M.; Inoue, K.; Kuriyama, S.; Sone, T.; Matsuda-Ohmori, K.; Nakaya, N. et al. (2008): Sleep duration and the risk of prostate cancer: the Ohsaki Cohort Study. In: British journal of cancer, Jg. 99, H. 1, S. 176–178. Online verfügbar unter doi:10.1038/sj.bjc.6604425. Abstract In a prospective study of prostate cancer incidence (127 cases), among 22 320 Japanese men, sleep duration was associated with lower risk; the multivariate hazard ratio of men who slept >or=9 h per day compared with those who slept less was 0.48 (95% confidence interval: 0.29-0.79, P for trend=0.02). Schlagwörter Aged; Humans; Incidence; Japanepidemiology; Male; Middle Aged; Prospective Studies; Prostatic Neoplasmsepidemiologyetiology; Risk Factors; Sleep; Time Factors Kakizaki, M.; Kuriyama, S.; Sone, T.; Ohmori-Matsuda, K.; Hozawa, A.; Nakaya, N. et al. (2008): Sleep duration and the risk of breast cancer: the Ohsaki Cohort Study. In: British journal of cancer, Jg. 99, H. 9, S. 1502–1505. Online verfügbar unter doi:10.1038/sj.bjc.6604684. Abstract In a prospective study of 23 995 Japanese women, short sleep duration was associated with higher risk of breast cancer (143 cases), compared with women who slept 7 h per day, the multivariate hazard ratio of those who slept
iLib08 - Citavi

Schlagwörter

investigate the association between LAN and breast cancer incidence rates and, as a test of the specificity of our method, lung cancer incidence rates in women across localities under the prediction of a link with breast cancer but not lung cancer. After adjusting for several variables available on a population level, such as ethnic makeup, birth rate, population density, and local income level, a strong positive association between LAN intensity and breast cancer rate was revealed (p<0.05), and this association strengthened (p<0.01) when only statistically significant factors were filtered out by stepwise regression analysis. Concurrently, no association was found between LAN intensity and lung cancer rate. These results provide coherence of the previously reported case-control and cohort studies with the codistribution of LAN and breast cancer on a population basis. The analysis yielded an estimated 73% higher breast cancer incidence in the highest LAN exposed communities compared to the lowest LAN exposed communities. Breast Neoplasms; Female; Humans; Israel; Light; Lung Neoplasms; Multivariate Analysis; Risk Factors

Kloog, Itai; Haim, Abraham; Stevens, Richard G.; Portnov, Boris A. (2009): Global co-distribution of light at night (LAN) and cancers of prostate, colon, and lung in men. In: Chronobiology international, Jg. 26, H. 1, S. 108–125. Online verfügbar unter doi:10.1080/07420520802694020. Abstract The incidence rates of cancers in men differ by countries of the world. We compared the incidence rates of three of the most common cancers (prostate, lung, and colon) in men residing in 164 different countries with the population-weighted light at night (LAN) exposure and with several developmental and environmental indicators, including per capita income, percent urban population, and electricity consumption. The estimate of per capita LAN exposure was a novel aspect of this study. Both ordinary least squares (OLS) and spatial error (SE) regression models were used in the analysis. We found a significant positive association between population exposure to LAN and incidence rates of prostate cancer, but no such association with lung cancer or colon cancer. The prostate cancer result is consistent with a biological theory and a limited number of previous studies of circadian disruption and risk. The LAN-prostate cancer connection is postulated to be due to suppression of melatonin and/or disruption of clock gene function. An analysis holding other variables at average values across the 164 countries yielded a risk of prostate cancer in the highest LAN-exposed countries 110% higher than in the lowest LAN exposed countries. This observed association is a necessary condition for a potentially large effect of LAN on risk of prostate cancer. However, it is not sufficient due to potential confounding by factors that increase the risk of prostate cancer and are also associated with LAN among the studied countries.