Men with chronic insomnia who slept for less than six hours were four times more likely to die during the 14-year follow-up period, according to a new study. Results were adjusted for potential confounders such as body mass index, smoking status, depression and obstructive sleep apnea. Further adjustments for hypertension and diabetes had little effect on the elevated mortality risk. No significant mortality risk was found in women with insomnia and a short sleep duration of less than six hours.