Menopausal vasomotor symptoms (ie, hot flashes and night sweats) have been associated with unfavorable risk factors and surrogate markers of cardiovascular disease, but their association with clinical cardiovascular disease events is unclear.

To examine the associations between different components of vasomotor symptoms, timing of vasomotor symptoms, and risk of cardiovascular disease.

We harmonized and pooled individual-level data from 23,365 women in 6 prospective studies that contributed to the International Collaboration for a Life Course Approach to Women’s Reproductive Health and Chronic Disease Events consortium. Women who experienced cardiovascular disease events before baseline were excluded. The associations between frequency (never, rarely, sometimes, and often), severity (never, mild, moderate, and severe), and timing (before or after age of menopause; ie, early or late onset) of vasomotor symptoms and incident cardiovascular disease were analyzed. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals.

In the adjusted model, no evidence of association was found between the frequency of hot flashes and incident cardiovascular disease, whereas women who reported night sweats “sometimes” (hazard ratio, 1.22; 95% confidence interval, 1.02–1.45) or “often” (hazard ratio, 1.29; 95% confidence interval, 1.05–1.58) had higher risk for cardiovascular disease. Increased severity of either hot flashes or night sweats was associated with higher risk of cardiovascular disease. The hazards ratios of cardiovascular disease in women with severe hot flashes, night sweats, and any vasomotor symptoms were 1.83 (95% confidence interval, 1.22–2.73), 1.59 (95% confidence interval, 1.07–2.37), and 2.11 (95% confidence interval, 1.62–2.76), respectively. Women who reported severity of both hot flashes and night sweats had a higher risk for cardiovascular disease (hazard ratio, 1.55; 95% confidence interval, 1.24–1.94) than those with hot flashes alone (hazard ratio, 1.33; 95% confidence interval, 0.94–1.88) and night sweats alone (hazard ratio, 1.32; 95% confidence interval, 0.84–2.07). Women with either early-onset (hazard ratio, 1.38; 95% confidence interval, 1.10–1.75) or late-onset (hazard ratio, 1.69; 95% confidence interval, 1.32–2.16) vasomotor symptoms had an increased risk for incident cardiovascular disease compared with women who did not experience vasomotor symptoms.

Severity rather than frequency of vasomotor symptoms (hot flashes and night sweats) was associated with increased risk of cardiovascular disease. Vasomotor symptoms with onset before or after menopause were also associated with increased risk of cardiovascular disease.