Article Text
Abstract
Background Multimorbidity, the co-occurrence of two or more chronic conditions in one person, is more common in women than in men. It is associated with lower life expectancy, lower quality of life, and greater use of health services compared to single diseases. Research on risk factors for cardiovascular multimorbidity (CVM), that is, having multiple cardiovascular diseases (CVDs), has been limited. We aimed to identify potential risk factors for CVM in women.
Methods The Million Women Study is a cohort of 1.3 million women aged 50–64 years, recruited in England and Scotland in 1996–2001 through NHS screening centres. Participants completed an extensive health and lifestyle questionnaire. Record linkage with NHS databases provided hospital admission records. Twenty chronic CVDs were selected based on clinical importance and number of records, primarily from chapter IX of the International Classification of Diseases v10. Characteristics were compared between women with 0, 1 or 2+ CVDs recorded in self-reports and hospital admissions up to recruitment, adjusting for five age categories (referent: 56–59 years).
Results Among 1,272,020 women, 0.7% (n=8463) had CVM and 5.3% (66,805) had one CVD. The most common CVDs were ischaemic heart disease (4.7%), stroke (1.2%), atrial fibrillation (0.2%), and venous thromboembolism (0.2%); among those with CVM, 85% had ischaemic heart disease and 54% had stroke. Women with CVM were older and, after adjustment for age, were more likely to have common cardiovascular risk factors. In women with no CVDs and those with CVM, respectively: 19.2% (95%CI 19.2–19.3) and 25.1% (24.1–26.0) were current smokers; 39.4% (39.4–39.6) and 22.7% (21.8–23.7) did strenuous physical activity at least once a week; mean BMI was 26.2 (26.1–26.2) and 28.1 (28.0–28.2). Women with CVM were substantially more likely to be in the most deprived fifth and have no educational qualifications. There was little association between CVM and reproductive factors, although women who had ever breastfed were slightly less likely to have CVM. Women with no CVDs were much less likely to report treatment for diabetes, hypertension, and high cholesterol than those with CVM; 15.0% (14.9–15.1) and 43.9% (42.9–45.0), respectively, were being treated for hypertension.
Conclusion Age-adjusted prevalence of CVM in UK women was associated with behavioural and socioeconomic characteristics, and with treatment for major cardiovascular risk factors, but largely not with reproductive factors. This cross-sectional study could not assess potential for reverse causation or confounding by other factors, and future prospective analyses will contribute to better understanding of these relationships.