Hongkongers now boast one of the highest life expectancy rates in the world, though a move to Macau could add on another two years. In the latest World Factbook annually published by the CIA, Hong Kong came in eighth in the world with an average life expectancy of just over 82 years. The average life span for Hong Kong men was 79 and 85 for women. People living in the European sovereign state of Monaco took pole position in the survey released this month, with an average life span of about 891/2 years, followed by Macau, where residents can expect to live to over 84. Japan came third at just under 84 years. The CIA figures for Hong Kong were slightly lower than the local Census and Statistics Department's figures from last year, which said men could expect to live to 80 and women to 86. Dr Karen Cheung Siu-lan, a social science expert from the University of Hong Kong, said it was a mystery as to why Hongkongers lived so long. 'We are living in such a crowded place with polluted air, stressful yet sedentary work style, excessive drinking and a diet with three highs - salt, sugar and oil - but people in Hong Kong still can enjoy a long life,' she said. Offering clues as to longevity is Cheung's recent study on healthy Hongkongers aged 100 or near that age. She interviewed more than 150 people born between 1905 and 1915, and took DNA and blood samples. 'Based on the preliminary results of the study [on centenarians], upbeat personality is one of the major conducive factors to healthy longevity,' Cheung said, adding there were 1,890 centenarians in the city. Other factors behind the trend included affordable and accessible health services, financial stability, healthy diet, regular exercise, and having a good social support base such as with family. The study was supported by the Hong Kong Council of Social Service, 18 elderly-health clinics and the Health Department. Cheung said a key finding was that 'most of the cognitively and physically intact centenarians were 'escapers' of fatal and chronic diseases such as cancer, heart and cerebrovascular diseases'. 'So living healthily and independently to 100 is not impossible today, if we could enhance the protective factors and reduce the risk factors,' she said. Separately, Macau University's Chan Kin-sun - a specialist in gerontology, or the study of ageing - said lower work pressure, and a stable social welfare and health care system contributed to longer life spans. The countries with the lowest life expectancy in the CIA survey were Chad, Guinea-Bissau, South Africa, Swaziland and Afghanistan.