MEN are more likely to continue having sex in old age if they maintain a 'prudent' lifestyle when younger and avoid the risk of developing conditions such as heart disease, high blood pressure and diabetes, say scientists from the New England Research Institute and the Boston University School of Medicine. In a study of nearly 1,300 men, aged from 40 and to 70, they found that men with these diseases were up to four times as likely to become impotent in later life - and that smoking further heightened the chances of impotence. Impotence is linked to disease, not ageing, concludes their study in the Journal of Urology.