Participation rates of women who were invited to provide cheek cell samples by means of mouthwash (swished in the mouth for about 45 seconds) were similar to those of women who were invited to provide cheek cell samples though swabs (rubbed on the inside of the cheek). However, the yield of DNA from the cheek cells was much greater from the mouthwash samples. Thus, cheek samples will be collected from BWHS participants by means of mouthwash.

Age at menopause influences the occurrence of osteoporosis, breast cancer, and other illnesses. Current smoking and a measure of racism (how often women thought about their race) were associated with an earlier natural menopause in preliminary analyses. The present results suggest that Black and white women share an important determinant of the age at natural menopause, cigarette smoking.

The hypothesis has been raised that later age at reaching adult height may be related to a reduced risk of breast cancer, because height may be a marker for later exposure to growth hormones and other hormones. BWHS data do not provide material support for this theory.

High retention rates in follow-up studies like the BWHS are essential for valid results. Participants in the BWHS are highly mobile, with 56% having moved at least once during the first follow-up period. Multiple sources of information were used to locate participants whose addresses were unknown, including the postal service, participants themselves through postcards, telephone calls, and emails, and contacts of participants. Adequate follow-up was attained, with the most cost-effective method for eliciting completed questionnaires being multiple mailings of questionnaires. link to online article

In recent years evidence from studies of white women has suggested that exercise may reduce the occurrence of breast cancer. Results from the BWHS are the first concerning Black women. Based on cases of breast cancer that participants reported when they entered the BWHS in 1995, strenuous physical activity in young adulthood was associated with reduced breast cancer risk. While the results suggest a protective effect of strenuous exercise, they are not definitive because it is necessary to demonstrate this with newly occurring cases of breast cancer. It will be possible to assess exercise in relation to newly occurring breast cancer in the BWHS after further years of follow-up. link to online article

In the past, lower rates of mammography use among Black women may have resulted in later diagnosis of breast cancer, leading to higher mortality rates than among white women. In 1997, the National Cancer Institute and American Cancer Society changed their mammography guidelines to recommend annual screening mammograms for women aged 40 and older. Information provided by BWHS participants in 1995 indicates that their rates of mammography use are high, and that a high proportion of women 40-49 made use of mammography even before the new guidelines were introduced. link to online article

BWHS data indicate that taller women have a slightly higher risk of developing breast cancer than shorter women. The difference in risk between tall and short women is too small to be of any importance to individuals, but it is of scientific interest because it may provide some clues about the causes of breast cancer. One theory is that taller women have more breast cells, providing more opportunity for a mutation to occur that leads to cancer. Another theory involves hormones that affect both height and cell division. link to online article