Women who go through menopause early - at ages 40 to 45 - have a higher rate of heart failure, according to a new study.
Smoking, current or past, can increase the risk, said researchers from the Karolinska Institute in Stockholm, Sweden.
The study is the first large-scale (including more than 22,000 postmenopausal women) and long-term study linking early menopause and heart disease.
It was made possible by the Swedish National Patient Register, which captures nearly all Sweden's hospitalisation and outpatient diagnoses; Sweden's Cause of Death Register; and health surveys of some 90,000 women in the Swedish Mammography Cohort, researchers said.
The authors' analysis of the data showed that women who went through menopause naturally at an early age had a rate of heart failure some 40 per cent higher than women who went through menopause the usual age between 50 and 54.
For every one-year increase in age at menopause, the rate of heart failure was 2 per cent lower.
Smokers are known to go through menopause an average of one year earlier than nonsmokers, but that didn't entirely explain the early menopause-heart failure connection, since women who had smoked earlier in their lives and quit also had an increased rate of heart failure with early menopause, researchers said.
Women who smoked, even if they had quit earlier, had a higher risk of heart failure if they went through menopause only somewhat early - at ages 46 to 49.
The study was published in Menopause, the journal of The North American Menopause Society (NAMS).