Wales\' chief medical officer has warned that increasingly unhealthy lifestyles may lead to a fall in life expectancy.Dr Tony Jewell said the problem was diseases caused by obesity, smoking, alcohol and fitness, with under one in three taking enough daily exercise.He said there had been a welcome reduction in young people taking up smoking and drinking but statistics for adults painted a far gloomier picture.His annual report calls for bold action to tackle these \"lifestyle factors\".Dr Jewell said these \"non-communicable\" diseases threatened to \"restrain or even result in a fall in life expectancy\".\"Unfortunately adult smoking levels remain comparatively high at 23%,\" he said.\"The number of adults that undertake the recommended level of daily physical activity are around 30%, and around 22% of adults are classified as obese.\"He also pointed out other parts of the UK and Europe were seeing better health improvements than Wales.Action was required to tackle these issues, led by the Welsh government, he said.He said the reduction in young people starting to drink and smoke was a \"welcome finding and a trend we must sustain as these crucial early influences are critical to life chances and future healthy life expectancy\".However, public health charity ASH Wales released figures on Monday saying that every day, an estimated 38 teenagers who have never smoked before try cigarettes.The figures were released ahead of a conference on tobacco and alcohol on 12-13 October.