SWAN | Study of Women’s Health Across the Nation

In 1994, SWAN was designed as a multi-site, observational study to be conducted in three phases. The initial phase consisted of focus groups of women with characteristics similar to those subsequently enrolled in SWAN. These focus groups were conducted in order to develop the most effective and culturally sensitive study design and protocols for recruiting and retaining diverse groups of women into SWAN.

The second phase was the cross-sectional survey, a 15-minute interview, which was administered to women who met the following criteria: residence within the geographic area specified by the clinical site; ability to speak and read English or the designated language (Chinese, Japanese or Spanish) of the clinical site, age 40-55; and self-identification within one of the two race/ethnicity groups studied at the clinical site. Each site used population survey methods to contact a generally representative group of women for the cross-sectional telephone interview. Interviews were conducted by telephone or in person. The SWAN cross-sectional screener dataset has been archived at the National Archive of Computerized Data on Aging (NACDA). To find out more go to the NACDA website, click on search holdings and type in SWAN.

In the third phase, eligible premenopausal women were enrolled from the cross-sectional phase into the longitudinal follow-up study. Women who met the eligibility criteria were 42-52 years old, had a uterus and at least one intact ovary, reported a menstrual period within the past three months and had not taken hormone medications (such as birth control pills, estrogen or progesterone preparations) in the last three months. Enrollment into this phase began in January 1996 and all seven clinical sites completed the baseline visit by December 1997. A total of 3,302 eligible women were enrolled into the longitudinal study population of SWAN and completed the baseline study (1,550 Caucasian, 935 African American, 286 Hispanic, 250 Chinese, and 281 Japanese).

Visits take place every year. The annual visit includes the following core components: physical measures (weight, height, hip, waist, and blood pressure), fasting morning blood draw, interviewer-administered and self-administered questionnaires. Women are also given menstrual calendars to complete monthly over the next year. All questionnaires are translated into Spanish, Cantonese, and Japanese and can be administered by bilingual interviewers. Completion of the annual core protocol takes approximately 2 hours.

Annual Visit Participation Rates

Ten annual follow-up visits have been completed to date.

The first annual follow-up visit began in February 1997 and was completed by January 1999. A total of 2,882 women completed visit 01, 87% of the baseline cohort.
Data collection for visit 02 began in March 1998, and was completed by April 2000. A total of 2,749 women completed visit 02, 83% of the baseline cohort.
The third round began in February 1999 and was completed in January 2001. A total of 2,711 women completed visit 03, 82% of the baseline cohort.
Data collection for visit 04 began in February 2000 and was completed by January 2002. A total of 2,684 women completed visit 04, 81% of the baseline cohort.
Data collection for visit 05 began in 2001 and was completed in 2003. A total of 2617 women completed visit 05, 79% of the baseline cohort.
Data collection for visit 06 began in March 2002 and was completed in February 2004. A total of 2442 women completed visit 06, 74% of the baseline cohort.
Data collection for visit 07 began in May 2003 and was completed by January 2005. A total of 2406 women completed the 07 visit, 73% of the baseline cohort.
Data collection for visit 08 began in March 2004 and was completed by January 2006. A total of 2272 women completed the 08 visit, 69% of the baseline cohort.
Data collection for visit 09 began in February 2005 and was completed by January 2007. A total of 2255 women completed the 09 visit, 68% of the baseline cohort.
Data collection for visit 10 began in February 2006 and was completed by January 2008. A total of 2245 women completed the 10 visit, 68% of the baseline cohort.
SWAN is currently fielding a non-funded interim visit 11 and expects to be complete by January 2009.

By the end of the current funding period in 2009, twelve annual visits will have been completed.

This Timeline Illustrates SWAN Visits