Later Menstrual Period and Long-Term Breastfeeding May Increase Lupus Risk in Black Women

A new study published in the journal Lupus has suggested that several factors related to reproduction may play a role in Black women’s risk of developing lupus. The researchers found that later age of first menstrual cycle (age of the first period, also called menarche) and longer length of breastfeeding may increase Black women's lupus risk.

Specifically, those who started their period after age 15 (compared to those who started at age 12) and those who had breastfed for more than 6 months (compared to those who had never breastfed) had a higher risk of developing lupus. Longer-term breastfeeding roughly doubled a Black woman’s lupus risk, while later age of first period led to a 70 percent increase in risk.^1,2

How was the study designed?

The research team followed more than 58,000 Black women who participated in the Black Women’s Health Study (BWHS). The BWHS was completed between 1995 and 2015 and asked participants to fill out health-related questionnaires every other year. In total, 125 of the participants developed lupus, and their reproductive-related risk factors were compared to those who did not develop the condition.¹

The impact of other reproductive factors

As mentioned, the main factors impacting lupus risk were longer-term breastfeeding and later age of the first period. However, there were other factors identified that did not have as big of a risk on lupus development. These included:¹

• Number of children a woman had
• Age of woman at the time she gave birth to her first child
• Whether or not a woman had gone through menopause
• Woman’s age at menopause
• Whether or not a woman had a hysterectomy (an operation to remove the uterus)
• Having a history of endometriosis (a condition that involves uterine tissue growing outside of the uterus)

The average age the women in the study developed lupus was 43 years old.¹

Additional research from the same team

The same team of researchers also looked at similar data from people enrolled in the Nurses’ Health Study, another long-term study. However, the people involved in this project were mostly White women. Interestingly, in this past study, early age of first period (rather than late) and menstrual cycle irregularities were associated with an increased risk of developing lupus.²

Why is this research important?

Currently, there is no scientific agreement on what exactly causes lupus. Current theories suggest that a variety of factors may work together to lead to developing the condition. Some of these include genetics, environmental triggers like smoking or stress, drugs, and more.

Experts have even suggested that hormones may play a role in lupus development or its symptoms. Finding out more about the potential relationship between hormones and lupus can create a window into understanding more about who may be at risk. Also, for unknown reasons, Black women are more commonly affected by lupus. Doing more research into both hormones and race may provide even greater insight.³

What do these findings mean?

Ultimately, these results suggest that certain hormonal and reproductive factors may play a role in lupus development. However, although these findings are interesting, they are only part of a larger picture. Specific results from the study need to be strengthened and further investigated by other studies before major changes are made.

For example, even though this study suggested that breastfeeding for longer periods of time may increase lupus risk, there are still benefits to breastfeeding for mothers and babies. Weighing risks and benefits, as well as further investigating the potential lupus-breastfeeding relationship, are important before making any significant changes to recommendations for women with lupus.