Light at Night Co‐distributes with Incident Breast but not Lung Cancer in the Female Population of Israel

  title={Light at Night Co‐distributes with Incident Breast but not Lung Cancer in the Female Population of Israel},
  author={Itai Kloog and Abraham Haim and Richard G. Stevens and M. Barchana and Boris A. Portnov},
  journal={Chronobiology International},
  pages={65 - 81}
Recent studies of shift‐working women have reported that excessive exposure to light at night (LAN) may be a risk factor for breast cancer. However, no studies have yet attempted to examine the co‐distribution of LAN and breast cancer incidence on a population level with the goal to assess the coherence of these earlier findings with population trends. Coherence is one of Hill's “criteria” (actually, viewpoints) for an inference of causality. Nighttime satellite images were used to estimate LAN… 

Nighttime light level co-distributes with breast cancer incidence worldwide

A significant positive association between population LAN level and incidence rates of breast cancer is found and provides coherence of the previously reported case–control and cohort studies with the co-distribution of LAN and breast cancer in entire populations.

Domestic light at night and breast cancer risk: a prospective analysis of 105 000 UK women in the Generations Study

There was no evidence that LAN exposure increased the risk of subsequent breast cancer, although the suggestion of a lower breast cancer risk in pre-menopausal women with a history of night waking in their twenties may warrant further investigation.

A case-referent study: light at night and breast cancer risk in Georgia

Positive associations between LAN and BC incidence are suggested, especially among whites, and the consistency of the findings with previous studies suggests that there could be fundamental biological links between exposure to artificial LAN and increased BC incidence.

Outdoor light at night and postmenopausal breast cancer risk in the NIH‐AARP diet and health study

Higher outdoor LAN exposure may be a risk factor for postmenopausal breast cancer, and the relationship between LAN and breast cancer risk may differ by individual characteristics, such as smoking, alcohol drinking, sleep duration and BMI, and neighborhood environment.

Testing the Light-at-Night (LAN) Theory for Breast Cancer Causation

The “light-at-night” (LAN) theory began with a focus on the mystery of breast cancer but it is now becoming evident that artificial lighting, and the circadian disruption that can result, may also influence the risk of some other diseases of modern life, such as prostate cancer in men, adultonset diabetes, and obesity.

Outdoor light at night at residences and breast cancer risk in Canada

No association was found between residential outdoor LAN and breast cancer for either measure of LAN when considering interactions for menopausal status and past/current night work status, consistent with studies reporting that outdoor LAN has a small effect or no effect on breast cancer risk.

Light at Night and Breast Cancer Risk Among California Teachers

Women living in areas with high levels of ambient light at night may be at an increased risk of breast cancer, and future studies that integrate quantitative measurements of indoor and outdoor light atnight are warranted.

Light-at-night, circadian disruption and breast cancer: assessment of existing evidence.

  • R. Stevens
  • Medicine
    International journal of epidemiology
  • 2009
If a consensus eventually emerges that LAN does increase risk, then the mechanisms for the effect are important to elucidate for intervention and mitigation and will provide for the development of lighting technologies at home and at work that minimize circadian disruption, while maintaining visual efficiency and aesthetics.



Shift work, light at night, and breast cancer on Long Island, New York.

The hypothesized association between breast cancer and circadian disruption was evaluated in the Electromagnetic Fields and Breast Cancer on Long Island Study, and results suggest positive associations with residential light-at-night exposure, or they could reflect response biases.

Increased Breast Cancer Risk among Women Who Work Predominantly at Night

The odds ratio for breast cancer among women who worked at night at least half of a year was 1.5 (95% confidence interval, 1.2 to 1.7), and there was a tendency to increasing odds ratio by increasing duration of nighttime employment.

Night Work and Risk of Breast Cancer

Women who reported more than 20 years of rotating night shift work experienced an elevated relative risk of breast cancer compared with women who did not report any rotating nightShift work.

A prospective study on habitual duration of sleep and incidence of breast cancer in a large cohort of women.

No convincing evidence is found for an association between sleep duration and the incidence of breast cancer in the Nurses' Health Study using Cox proportional hazards models.

Reduced Cancer Incidence among the Blind

The hypothesis that blind people have a decreased cancer incidence is supported, although other explanations than the higher melatonin exposure must also be considered.

Breast Cancer and Night Work among Norwegian Nurses

The relationship among Norwegian nurses educated between 1914 and 1980 is evaluated, finding an association between night work and breast cancer risk among women in accordance with previous studies.

Melatonin-depleted blood from premenopausal women exposed to light at night stimulates growth of human breast cancer xenografts in nude rats.

These mechanistic studies are the first to provide a rational biological explanation for the increased breast cancer risk in female night shift workers and show that the tumor growth response to exposure to light during darkness is intensity dependent and that the human nocturnal, circadian melatonin signal not only inhibits human breast cancer growth but that this effect is extinguished by short-term ocular exposure to bright, white light at night.

Cancer and Laterality: A Study of The Five Major Paired Organs (UK)

The results suggest that tissue mass in these organs is an important contributor to asymmetry in cancer incidence, and particularly in the lungs and testes, which closely coincided with asymmetries in organ size.