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MONDAY, Nov. 17, 2014 (HealthDay News) -- Women who started smoking at a young age may be at increased risk for chronic, severe menstrual pain, a new study suggests.

About 29 percent of women experience severe menstrual pain. While smoking has been suspected as a risk factor for severe menstrual pain, the evidence has been inconclusive, the authors of the new study said.

The researchers analyzed data from 9,000 women taking part in a long-term study of women's health in Australia. About 14 percent of the women had chronic, severe menstrual pain.

Current smokers who started smoking by age 13 were more likely to have chronic, severe menstrual pain, as were women who were unemployed, began having their periods at a younger age, were obese and spoke a European language at home.

When the investigators took other factors into account, they concluded that current smokers who started smoking by age 13 were 60 percent more likely to have chronic, severe menstrual pain than nonsmokers.

The study was published online Nov. 17 in the journal Tobacco Control.

Dr. Hong Ju, of the University of Queensland in Brisbane, Australia, and colleagues pointed out in a journal news release that because this was an observational study, no definitive conclusions can be drawn about cause and effect. However, there are possible explanations for the association, the authors suggested.

Smoking is known to reduce blood flow in the arteries, which could cause severe menstrual pain, according to the researchers. They also said that smoking may affect hormones involved in menstruation.

More information

The U.S. National Library of Medicine has more about menstrual pain.