Dysmenorrhea and stroke are prevalent disorders in women [1–5]. Dysmenorrhea, characterized by abdominal pain, cramps, nausea, headaches, and diarrhea, occurs during menstruation. Dysmenorrhea can be categorized as primary and secondary, based on onset and persistence [4, 5]. Primary dysmenorrhea, occurring 3 years after the first menstrual cycle, affecting young women (15–25 years of age) is the more prevalent and widely studied form of dysmenorrhea [5–8]. The secondary dysmenorrhea is associated with a specific underlying cause of reproductive organ. The global prevalence of dysmenorrhea ranges from 28–87.4% [4–9].
Stroke is one of the leading causes of deaths, after cardiovascular diseases and cancer . Persky et al. reported that each year, approximately 55,000 more women than men suffer from strokes, including recurrent strokes. If the current trend continues, it has been estimated that 60% of all stroke cases will be women by 2030 . In 2012, the proportional mortality associated with stroke was estimated at 7.2%, which results in an economic burden of roughly US$75 million annually. In Taiwan, stroke is the third-leading cause of deaths .
Among subtypes of stroke, ischemic stroke (IS) is the most common type, referring to a blockage of blood flow to the brain, which may account for approximately 75% of all stroke cases [11–13]. Causing by a leakage of blood in the brain, hemorrhagic stroke (HS) has been associated with high blood pressure and aneurysms [14, 15]. Transient ischemic attack (TIA) is a warning sign of future major stroke events. TIA is characterized as a blockage of blood flow to the brain for a short period of time, commonly less than five minutes .
Women face a high risk of stroke, and this risk appears to be growing. In Taiwan, nearly 74% of all stroke cases are IS, a much greater proportion than cases of HS (19.1%) and TIA (6.7%) . It should be noted that dysmenorrhea in women is associated with mutual comorbidities of stroke, including cardiovascular disorders and thyroid diseases [17–19]. In the recent Chinese Project ELEFANT, Xu et al. found that young women with dysmenorrhea are at an increased risk of hypertension, and the estimated risk increases as the duration of menstrual bleeding increases . A recent study using the Mayo Clinic’s Spontaneous Coronary Artery Dissection (SCAD) registry data found that chest pain is prevalent in women prior to menstruation . A New Delhi study found that women with menstrual disorders are prevalent with thyroid disorders, 14% of these disorders being diagnosed with hypothyroidism and 8% being diagnosed with hyperthyroidism .
Although stroke and dysmenorrhea are related to mutual risk factors, few researchers have investigated the association between the two conditions. A recent case-control study using insurance-claims data of women with dysmenorrhea in Taiwan suggested that stroke-related disorders are more prevalent in stroke cases than in non-stroke controls . The disorders included hypertension (adjusted odds ratio [aOR] 4.53 [95% confidence interval (CI) 3.46–5.92]), hyperlipidemia (aOR 1.60 [95% CI 1.19–2.15]), arrhythmia (aOR 1.80 [95% CI 1.31–2.46]), and thyroid disease (aOR1.56 [95% CI 1.20–2.02]). HS is more prevalent than IS in younger women suffering from dysmenorrhea.
Stroke can result in physical disability and dependence on others, both of which impose high economic costs . Stroke costs an estimated $34 billion each year in the United States . The pain and psychological distress caused by dysmenorrhea also prevent many individuals from performing daily activities, resulting in a loss of work hours. It should, however, be noted that it remains unclear how the occurrence of stroke among women with dysmenorrhea affects the cost of care. Limited study has evaluated whether the stroke types and costs in women with dysmenorrhea differ from those in women without dysmenorrhea . The occurrence of dysmenorrhea and stroke vary by age . In this study, we adopted a follow-up approach to conduct a retrospective cohort study to compare the occurrence of stroke and costs for care by stoke type between women with and without dysmenorrhea using insurance-claims data. The design made it possible for follow-up with the women in order to determine outcomes of stroke, including costs by the type of stroke .