Why Residents of South China live longer than those of North China?

Background: , Since 1990, life expectancy and nonagenarian ratio in South China have been higher than those in North China. Methods, To determine the reason residents of South China live longer, we calculated age-specific mortality rates (per 100,000 people) in North and South China. We examined the associations between the provincial mortality rates due to major fatal diseases and life span indicator. Results, CVD is the leading cause of death in China. The proportion of CVD in all-cause mortality increases with age, and its mortality rate accounts for over 50% of all-cause mortalities in people aged over 80 years. Moreover, the mortality rate of CVD gradually decreases from north to south, indicating the main reason of difference in longevity between North and South China. This difference can be attributed to variations in temperature, salt consumption, selenium intake, air pollution, overweight and obesity between the two regions. Lower mortality rates of individuals aged 55–89 years in South China lead to higher longevity level. Provincial gravity centers of the proportion of longevity population move southward, and this shift is accelerated with increasing age. Conclusions, the mortality rate of CVD gradually decreases from north to south is the reason residents of South China live longer, and risk factors of CVD gradually decreases from north to south.