Reproductive and Hormonal Risk Factors for Breast Cancer in Blind Women
Abstract
Epidemiological observations indicate that breast cancer risk is lower in visually impaired women compared to sighted women and that the risk is inversely correlated with degree of visual impairment. A hypothesis to explain these findings is that blind people are less susceptible to suppression of melatonin by light exposure at night and therefore have higher levels of melatonin. Melatonin has oncostatic properties in vitro. In a survey of 12,000 blind women, the authors will test the following hypothesis: the distribution of known reproductive risk factors for breast cancer among blind women will be consistent with lower risk when compared to the general population. In a subset of 240 women, the authors will test the following hypotheses: urinary melatonin levels will be lower and estrogen levels will be higher among blind women with light perception compared to blind women without light perception; and melatonin levels will be higher and estrogen levels will be lower among totally blind women who have non-24-hour melatonin rhythms and, therefore, a confirmed absence of light-induced suppression of melatonin, compared to totally blind women who have 24-hour melatonin rhythms and may be affected by light. Data collection is ongoing and there are no results to report at this time.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2005
- Accession Number
- ADA438151
Entities
People
- Steven W. Lockley
Organizations
- Brigham and Women's Hospital