The study, lead-authored by Thomas Houston of the Birmingham Veterans Affairs Medical Center in Alabama, found smokers had the highest risk of developing glucose intolerance, a precursor to diabetes, at 22 percent, compared to a 17 percent chance of developing it for passive smokers.

    Non-smokers who were not exposed to other people's smoke had the least risk at 12 percent, while smokers who had given up had a14 percent risk.

    "We identified passive tobacco exposure in people who have never smoked as a new risk factor for glucose intolerance," said Houston.

    The study of the impact of smoking, conducted by Houston and his team, involved more than 4,000 men and women in four American cities over 15 years. Enditem