There is new medical evidencefor the expression "better late than never."Researchers have found that smokers reduce their risk of dying from tobacco even if they stop smoking after the age of sixty.Smoking is a known risk for many diseases,including many forms of cancer as well as heart disease.But most studies on the health effects of smokinginvolve middle-aged people.The latest analysis by German researchersexamined the findings of seventeen studiescarried out in the United States, China,Australia, Japan, England, Spain and France.Smokers sixty and older had an eighty-three percentincreased risk of dying from all causescompared to people who had never smoked.Smokers also had a thirty-four percenthigher risk of death compared to former smokers.T.H. Lam is professor in the school of public healthat the University of Hong Kong.He says people who continue to smoke as seniorshave at least a fifty percent chance of dyingfrom their smoking habit.T.H. LAM: "And if they stop smoking,then they can reduce about one-quarter of their excess risk.So this is good news that older people should not continue to smoke."What about smokers who start at a young ageand stop when they are in their thirties?Dr. Lam says they can reduce their risk of dyingfrom a smoking-related illness to almost the same levelas someone who never smoked.Even people who never smoke can still diefrom breathing other people's secondhand smoke.An article on smoking among older individuals,with a commentary by T.H. Lam,appeared in the Archives of Internal Medicine.In other news, the World Health Organization now saysdiesel fuel exhaust causes cancer.Since nineteen eighty-eight the WHO had rated exhaustfrom diesel engines as "probably carcinogenic" to humans.Now, it compares the riskto that of secondhand cigarette smoke.This month's announcement came after international expertsspent a week reviewing new research findings.Those included a long-term study ofmore than twelve thousand minerswho were heavily exposed to diesel exhaust.The diesel industry pointed out that the mining studylacked exact data on exposure levels during its early years.Also, diesel engine makers point to their new designsthat produce far less emissions than older truck and bus engines.The WHO says stronger standardsare needed to limit diesel emissions into the air.The United States Environmental Protection Agencycontinues to rate diesel as only a "likely" cause of cancer.And that's the VOA Special English Health Report.