Smoking brings on the menopause

Norwegian researchers have discovered that women who smoke are 59 percent more likely than non-smokers to have an early menopause.

The researchers say smokers are more likely to begin the menopause before the age of 45 putting themselves at an increased risk of osteoporosis and heart disease.

Dr. Thea F. Mikkelsen of the University of Oslo and her colleagues found that among 2,123 women 59 to 60 years old, those who currently smoked were 59 percent more likely than non-smokers to have undergone early menopause and for the heaviest smokers, the risk of early menopause was almost double.

The researchers also found that women who were smokers, but quit at least 10 years before menopause, were substantially less likely than current smokers to have stopped menstruating before age 45.

Mikkelsen and her team say evidence already exists which shows that smoking later in life makes a woman more likely to have early menopause, while smokers who quit before middle age may not be affected.

However the researchers went one step further and investigated whether exposure to second-hand smoke might also influence the timing of menopause.

They found that almost 10 percent of the women went through menopause before age 45 and of that number around 25 percent were current smokers, 28.7 percent were ex-smokers and 35.2 percent reported current passive exposure to smoke.

The women who had quit smoking at least a decade before menopause were 87 percent less likely than their peers who currently smoked to have gone through menopause early.

When they were compared with married women, widows were also at increased risk of early menopause, as were women who were in poor health.

In general the better educated women were less likely to go into menopause early, but they were also less likely to be smokers.

A good social life also appeared to cut the early menopause risk and the researchers found no link between coffee or alcohol consumption or passive exposure to smoke and early menopause risk.

Mikkelsen and her team say the earlier a woman stops smoking the more protection she derives with respect to an early onset of menopause."

The research is published in the online journal "BMC Public Health."