Menstrual cycle regularity as a predictor for heart disease and diabetes: Findings from a large population‐based longitudinal cohort study

Abstract

Objective Menstrual cycle regularity underpins the diagnosis of polycystic ovary syndrome (PCOS), which is linked to adverse cardio‐metabolic profile. However, links between menstrual disorders and metabolic conditions are often under‐appreciated and not considered when assessing cardio‐metabolic risk in women. We aimed to assess the risk of diabetes and heart disease in women with irregular menstrual cycles and those whose cycles were regular. Methods This was a community based longitudinal cohort study. We utilized the 1946 to 1951 birth cohort database (N = 13,714) of the Australian Longitudinal Study on Women's Health (ALSWH) over a 20‐year follow‐up period. Data were analysed using Cox regression models. Results Women with irregular menstrual cycles had 20% higher risk of developing heart disease [adjusted hazard ratio [HR]: 1.20, 95% confidence interval [CI]: 1.01–1.43) compared with those with regular menstrual cycles. We also observed 17% higher risk of diabetes (HR: 1.17, 95% CI: 1.00–1.38) in women who had irregular menstrual cycles than in women who had regular menstrual cycles. The diabetes risk was 30% higher (HR: 1.30, 95% CI: 1.09–1.55) if women had irregular cycles and did not use hormone replacement therapy, but this was not significant on adjustment for all covariates. Conclusion Having irregular menstrual cycles appears to be an early indicator for heart disease and diabetes. These findings suggest that irregular cycles among women in their forties may be linked to adverse cardio‐metabolic outcomes. These women may benefit from screening and prevention strategies as recommended by related guidelines such as the international evidence‐based guideline for the assessment and management of PCOS.

Prospective Risk of Type 2 Diabetes in Normal Weight Women with Polycystic Ovary Syndrome

“…Selection of studies was crosschecked by evaluation of reference lists of three recent reviews regarding metabolic outcomes in PCOS [ 7 , 14 , 15 ], which did not add additional references. Two publications included data from the Australian Longitudinal Study on Women’s Health [ 25 , 27 ], which implied overlapping study cohorts. The paper by Glintborg [ 29 ] provided additional data to the paper from the same study group [ 9 ], and the results were presented as one publication [ 29 ].…”

“…The studies were published 2010–2021 and performed in European [ 8 , 9 , 18 , 29 , 34 , 35 , 37 ], Northern American [ 31 , 32 ], Asian [ 26 , 28 , 30 , 33 ], and Oceanic [ 25 , 27 ] study cohorts. No study was conducted in Southern American or African study cohorts.…”

“…The definition of PCOS was based on clinical evaluation [ 28 , 29 , 30 , 32 , 33 , 34 , 35 , 37 ], ICD10 diagnosis code [ 18 , 26 ], or self-reported data from questionnaires or interviews [ 8 , 25 , 26 , 31 ]. Wang [ 31 ] applied questionnaires regarding menstrual status in combination with measurement of serum testosterone levels.…”

“…Diagnosis of T2D was based on OGTT [ 8 , 28 , 33 , 34 , 35 , 37 ] or fasting blood glucose [ 31 , 32 , 35 ], ICD-10 diagnosis code [ 18 , 27 , 33 ], or self-reported [ 25 , 27 ]. Medical treatment for T2D (excluding metformin) was added to ICD10 diagnosis code by two studies [ 18 , 29 ].…”

“…Four controlled studies reported a higher risk of T2D in lean/normal weight women with PCOS compared to controls [ 18 , 26 , 31 , 33 ], whereas comparable risk for T2D in PCOS and controls was reported in the remaining six studies [ 8 , 25 , 27 , 32 , 34 , 35 ]. Studies reporting higher risk for T2D in PCOS included study populations from Sweden [ 18 ], Korea [ 26 ], Australia [ 27 ], and USA [ 31 ].…”