Long, Irregular Periods Linked to Increased Risk of NAFLD

Seungho Ryu, MD, PhD

Long or irregular periods could signal an increased risk for nonalcoholic fatty liver disease (NAFLD), according to the results of a recent study.

A cross-sectional study of more than 70,000 women younger than 40 years of age, results of the study demonstrate women with long or irregular menstrual cycles were at a 22% greater risk of NAFLD compared to the study’s reference group, with this increase in risk ballooning to nearly 50% in time-dependent analysis.

“Our study results show that long or irregular menstrual cycles may be associated with an increased risk of developing NAFLD, and this link was not explained by obesity,” said Seungho Ryu, MD, PhD, of the Center for Cohort Studies, Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine in Seoul, South Korea, in a statement. “Previous studies have shown that long or irregular menstrual cycles are associated with type 2 diabetes and cardiovascular disease, but our study is the first to find a link between long or irregular menstrual cycles and NAFLD.”

Although research has established definitive associations between presence of long or irregular menstrual cycles in women with increased risk of type 2 diabetes and cardiovascular disease, less is known about potential associations with NAFLD. To develop a better understanding of this association, investigators designed a cross-sectional study of data from Kangbuk Samsung Health Study, which consists of premenopausal Korean women younger than 40 years of age who underwent annual or biennial health examinations from 2011-2017.

Funded by the Sungkyunkwan University and the Southampton NIHR Biomedical Research Centre, the study’s cross-sectional analyses included 72,092 women and the longitudinal assessments included a subset of 51,118 women without NAFLD at baseline. Of the 72,092 women included in the cross-sectional analyses, 7.1% had NAFLD at baseline and 27.7% had long or irregular menstrual cycles.

For the purpose of analysis, long or irregular cycles were defined as menstrual cycles of 40 days or longer or too irregular to estimate and abdominal ultrasonography was performed to identify NAFLD. Investigators used multivariable Cox proportional hazard regression analyses to estimate hazard ratios for incident NAFLD according to menstrual cycle regularity and length, with 26–30-day cycles as the reference.

During a median follow-up of 4.4 years, incident NAFLD occurred in 8.9% of women. In the investigators’ analyses, long or irregular menstrual cycles were positively associated with prevalent NAFLD. Specifically, the risk for NAFLD among those with long or irregular menstrual cycles was 22% greater than that observed for the reference group after adjustment for age, BMI, insulin resistance, and other confounders (HR, 1.22; 955 CI, 1.14-1.31). Investigators pointed out this association strengthened in time-dependent analysis, with a 49% increase in risk compared to the reference group (HR, 1.49; 95% CI, 1.38-1.60)

“Young women with long or irregular menstrual cycles may benefit from lifestyle changes to reduce the risk of NAFLD as well as other cardiometabolic diseases,” Ryu added.

This study, “Long or Irregular Menstrual Cycles and Risk of Prevalent and Incident Non-Alcoholic Fatty Liver Disease,” was published in the Journal of Clinical Endocrinology and Metabolism.