Copyright 1999 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.
To the Editor: Dr Holmes and colleagues1 reported that analysis of data from the Nurses' Health Study found no evidence that a lower intake of dietary fat was associated with a decreased risk of breast cancer. These results, in a well-defined, prospective cohort study, differ from those of retrospective studies, international comparisons, meta-analyses of case-control studies, and laboratory animal studies.
Martinez et al,2 in a study of the relation of dietary calcium and vitamin D to the risk of colorectal cancer in the same group of women, found that vitamin D intake in these women was considerably higher than the US average, primarily due to their regular intake of multivitamin supplements. The average US woman consumed about 60 IU (1.5 µg) of vitamin D in 1987,3 while the women in the Nurses' Health Study had a median daily intake of more than 250 IU (6.25 µg), about 4-fold higher.
Garland et al4 found a strong inverse correlation between breast cancer and the availability of effective solar radiation for in vivo skin production of vitamin D. Coupled with the low average dietary intake of vitamin D, they suggested that inadequate vitamin D in the United States may be a significant risk factor for breast cancer. In animal studies5 variation of dietary calcium and vitamin D had little or no effect on carcinogen-initiated breast cancer in low-fat diets. However, increases in dietary calcium and vitamin D reduced tumorigenesis several-fold in diets with high fat (20% by weight, equivalent to 40% of energy intake).6 Taken together, animal and epidemiological studies suggest that increased vitamin D intake should result in a decreased breast cancer risk. Further, the animal data suggest that adequate increased vitamin D intake sharply reduces the effect of high dietary fat as a promoter of breast cancer.5 - 6
Therefore, it appears that the article of Holmes et al,1 coupled with that of Martinez et al,2 offers an explanation for the lack of effect of variation of dietary fat intake in breast cancer risk in the Nurses' Health Study, due to the higher vitamin D intake reducing the effect of fat on breast cancer risk. This cohort apparently is an educated, health-conscious population, as evidenced by their higher levels of multivitamin use, and resultant vitamin D intakes.
In at least this aspect of daily habits this particular study population, while large for a study cohort, is certainly not representative of the US female population as a whole. Careful consideration of differences between this study group and the average US female population must be made before generalized recommendations of public health policy can be formulated.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
Instructions
Comments are moderated and will appear on the site at the discretion of the Journal of American Medical Association editors. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest* Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more
Subscribe for full-text access to content from 1998 forward and a host of useful features
Activate your current subscription (AMA members and current subscribers)
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Customize your page view by dragging & repositioning the boxes below.
and access these and other features:
Register Now
Enter your username and email address. We'll send you a reminder to the email address on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.