Featured Research

from universities, journals, and other organizations

Overweight Young Women Have Reduced Risk Of Developing Breast Cancer Before Menopause

Date:
November 28, 2006
Source:
JAMA and Archives Journals
Summary:
A higher body mass index (BMI), especially in early adulthood, may be associated with a reduced risk of breast cancer before menopause, according to an article in the November 27 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. This association does not appear to be related to ovulation problems that overweight women may develop.

A higher body mass index (BMI), especially in early adulthood, may be associated with a reduced risk of breast cancer before menopause, according to an article in the November 27 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. This association does not appear to be related to ovulation problems that overweight women may develop.

Previous studies have observed an association between higher body mass index and a lower risk of breast cancer, according to background information in the article. High BMI can be associated with irregular or long menstrual cycles and the development of polycystic ovary syndrome, a condition that occurs when the ovaries malfunction, decreasing fertility and contributing to other illnesses. All of these are related to disruptions in ovulation, which decrease levels of the hormones estradiol and progesterone; the long-held belief was that these lower levels, in turn, might explain the decrease in breast cancer risk. "However, few studies have explored whether these or other factors provide mechanistic insights into the unexpected protection that a high body mass confers on the premenopausal breast," the authors write.

Karin B. Michels, Sc.D., Ph.D., Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues studied 113,130 premenopausal women who were part of the Nurses' Health Study II, a large group of female registered nurses who have been followed since 1989. At the beginning of the study, the women provided information about their adult height and their weight at age 18, as well as their current weight, any fertility problems, their family history of breast cancer and the characteristics of their menstrual cycle. Follow-up questionnaires that included questions about breast cancer and benign breast disease, childbirth, alcohol consumption, oral contraceptive use and physical activity were filled out every two years. The women were followed until 2003 or until they developed breast or any other cancer, died or reached menopause, whichever happened first.

Between 1989 and 2003, 1,398 cases of invasive breast cancer occurred among the women. Those with a current BMI of 30 or higher had a 19 percent lower risk of breast cancer compared with those who had a BMI between 20 and 22.4, after adjusting for family history, personal characteristics, lifestyle habits and menstrual variables. Women whose BMI was 27.5 or higher at age 18 had a 43 percent lower risk of developing breast cancer than those whose 18-year-old BMI was between 20 and 22.4. This association did not change when the researchers considered current BMI.

"A high BMI during adulthood is highly correlated with a high body mass during adolescence, which may be more important for the development of breast cancer before menopause," the authors write. "Although a high birth weight has been fairly consistently linked to an increase in the risk of premenopausal breast cancer, the BMI-breast cancer association seems to reverse at some point during the first years of life, only to revert back after menopause," when breast cancer is most often diagnosed.

Because the failure to ovulate (anovulation) cannot be measured directly, these findings do not rule out the hypothesis that factors related to ovulation contribute to the protective effect of a high BMI. "However, because adjustment for menstrual cycle patterns, infertility due to ovulatory disorder, probable polycystic ovary syndrome and use of oral contraceptives did not even slightly attenuate the association with BMI, anovulation does not seem to be a primary explanation for the reduced risk in heavier women," the authors conclude. "Among women with no history of infertility due to an ovulatory disorder, the inverse association between BMI and premenopausal breast cancer incidence persisted, lending further support to the role of mechanisms other than anovulation." The link may be hormonal, or due to the fact that obese women are less likely to be screened for breast cancer.


Story Source:

The above story is based on materials provided by JAMA and Archives Journals. Note: Materials may be edited for content and length.


Cite This Page:

JAMA and Archives Journals. "Overweight Young Women Have Reduced Risk Of Developing Breast Cancer Before Menopause." ScienceDaily. ScienceDaily, 28 November 2006. <www.sciencedaily.com/releases/2006/11/061128084438.htm>.
JAMA and Archives Journals. (2006, November 28). Overweight Young Women Have Reduced Risk Of Developing Breast Cancer Before Menopause. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2006/11/061128084438.htm
JAMA and Archives Journals. "Overweight Young Women Have Reduced Risk Of Developing Breast Cancer Before Menopause." ScienceDaily. www.sciencedaily.com/releases/2006/11/061128084438.htm (accessed July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

AFP (July 24, 2014) A so-called drugs rehab 'clinic' is closed down in Pakistan after police find scores of ‘patients’ chained up alleging serial abuse. Duration 03:05 Video provided by AFP
Powered by NewsLook.com
Too Few Teens Receiving HPV Vaccination, CDC Says

Too Few Teens Receiving HPV Vaccination, CDC Says

Newsy (July 24, 2014) The Centers for Disease Control and Prevention is blaming doctors for the low number of children being vaccinated for HPV. Video provided by Newsy
Powered by NewsLook.com
New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins