Global Co‐Distribution of Light at Night (LAN) and Cancers of Prostate, Colon, and Lung in Men

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.

Does the Modern Urbanized Sleeping Habitat Pose a Breast Cancer Risk?

“…The study revealed that exposure to LAN in the "sleeping habitat" was significantly associated with BC, controlling for education, ethnicity, fertility, and alcohol consumption. Our results are thus consistent with those of previous studies that revealed a significant LAN-BC association (Kloog et al, 2008(Kloog et al, , 2009a(Kloog et al, , 2009b(Kloog et al, , 2010Schernhammer et al, 2001). Our results also correspond with those of the case-control studies conducted by O'Leary and colleagues (2006) and Davis and colleagues (2001).…”

“…Although several empirical studies have been conducted to evaluate the effects of work-related and outdoor light pollution on hormone-dependent cancers (Davis et al, 2001;Kloog et al, 2008Kloog et al, , 2009aKloog et al, , 2009bKloog et al, , 2010Schernhammer et al, 2006), the association between LAN exposure in the bedroom of apartments and houses (which we term the "sleeping habitat") and cancer has largely escaped investigation, and the existing evidence is essentially scarce. In the framework of their Long Island study, O'Leary and colleagues (2006) conducted personal interviews to trace LAN-exposure histories at work and home.…”

Different Roles of Negative and Positive Components of the Circadian Clock in Oncogene-induced Neoplastic Transformation

“…For example, human night shift workers are at an increased risk of developing breast, prostate, colon, and endometrial cancers as well as hepatocellular carcinoma and non-Hodgkin lymphoma (6 -7). These epidemiological findings are also supported by animal studies in which repetitive changes in the light-dark cycle facilitate the growth of implanted tumors (8,9). Furthermore, spontaneous as well as radiation-induced tumor development is enhanced in circadian gene-defective animals whose behavioral and physiological rhythms are abnormal phenotypes (10,11).…”

Light Pollution of the Mountain Areas in Poland / Zanieczyszczenie Świetlne W Obszarach Górskich W Polsce

“…In addition to the defi nite infl uence of light pollution on local ecosystems, its impact on human health is also known [11,12,13,18]. Given the fact that there are many tourist resorts or even spas in the mountain areas, which should provide adequate rest comfort, one should consider the impact of the described effect on the quality of rest and treatment in these centers.…”