While the factors that determine how long you're going to live are mostly derived from your own personal genetic factors and lifestyle behaviors – including how many hours a week you work -- some factors of the environment around you also play a role. So says Dr. Stewart Newlove, managing director at medical research firm Antibodies.com, which analyzed 30 countries to see which have the highest average life expectancy rates – and which have the lowest. Not surprisingly, the research found a "distinct connection" between early vaccinations for children, access to sanitation and air quality on life expectancy. But there are "anomalies," Newlove says. "Lesotho, for example, has one of the highest child vaccination rates at 93 percent, but the shortest life expectancy, due to such high instances of AIDS and tuberculosis," he says. "Australia, on the other hand, has the highest prevalence of drug disorders, rate of meat consumption and second most common instances of obesity on the list, but has the world's fourth longest life expectancy." The research also found that long working hours – those exceeding 48 hours -- shorten life expectancy by nine years. Every hour spent at work per week above the recommended 48 hours shaves 2.25 years off one's life. Of the lowest life expectancy countries, the Central African Republic has the highest weekly working hours at 52 -- four hours above the maximum recommended amount. In comparison, France has the lowest working hours with just 35 per week and the average life expectancy of 82.9 years. READ MORE: How health issues and life expectancy differ from state to state Long life expectancy, expensive retirement Facing retirement in poverty, some Japanese choose prison