Sick passengers started complaining of vomiting and diarrhea Wednesday and were treated with over-the-counter medication, he said.

Most would be recovered by the time the ship docked Sunday morning in Port Canaveral as originally scheduled, Sheehan said.

The cruise included ports of call in the Bahamas, Virgin Islands and St. Maarten.

This is the second outbreak aboard the Mariner of the Seas this year. In January, the ship reported a norovirus that sickened 276 passengers and 27 crew members.

Noroviruses affect about 23 million Americans annually, and 16 incidents of the illness have been reported on cruise ships so far this year, according to the Centers for Disease Control.

While many studies have looked at the effect of overweight and obesity on mortality, Muennig and his team note, there is little information on how excess weight might affect a person's well-being while he or she is still alive. To investigate, the researchers used a measurement called the quality-adjusted life year (QALY), which represents a year of being perfectly healthy, to determine the burden of disease associated with obesity in a nationally representative sample of adults.

Most of the years of health that women lost to overweight and obesity were due to poor health-related quality of life and later-life mortality, the researchers note in the September issue of the American Journal of Public Health.

Death rates among overweight and obese women were lower than for men up until age 45; after age 45, women's mortality was far higher than men's.

Previous studies, which did not look at men and women separately, have suggested that being overweight may actually protect against mortality, Muennig told Reuters Health. "What we were shocked to find is that men were really the primary beneficiaries of any differences in the overweight category, and that women actually had much higher morbidity and mortality," he added.

In their report, the researchers suggest several explanations for the gender differences.

"To me what makes more sense is that there's just a lot more social stigma associated with being overweight amongst females, and that that causes a lot more stress and distress," Muennig said. "There's evidence showing that high levels of stress can increase your risk of morbidity and mortality."

The findings provide evidence, he added, that "the message that women are getting in the mass media about their weight is actually more harmful than we previously thought."