Background: Previous cross-sectional studies suggested a positive association between restless legs syndrome (RLS) and coronary heart disease (CHD). This observation was not confirmed by subsequent prospective studies. However, these prospective studies did not take into account the duration of RLS symptoms. Therefore, we prospectively examined whether RLS was associated with an increased risk of CHD in women who participated in the Nurses' Health Study, taking into account the duration of RLS symptoms.
Methods and results: A total of 70 977 women (mean age, 67 years) who were free of CHD and stroke at baseline (2002) were followed up until 2008. Physician-diagnosed RLS was collected via questionnaire. CHD was defined as nonfatal myocardial infarction or fatal CHD. Women with RLS at baseline had a marginally higher risk of developing CHD (multivariable-adjusted hazard ratio, 1.46; 95% confidence interval, 0.97-2.18) compared with women without RLS. The risk was dependent on duration of symptoms: 0.98 (95% confidence interval, 0.44-2.19) for women with RLS for <3 years and 1.72 (95% confidence interval, 1.09-2.73) for women with RLS for ≥3 years (P trend=0.03). The multivariable-adjusted hazard ratios of women with RLS for ≥3 years were 1.80 (95% confidence interval, 1.07-3.01) for nonfatal myocardial infarction and 1.49 (95% confidence interval, 0.55-4.04) for fatal CHD relative to women without RLS.
Conclusions: We observed that women with RLS for at least 3 years had an elevated risk of CHD. These results suggest that RLS or RLS-associated conditions may contribute to the origin of cardiovascular disease.