A new study published in the medical journal The Lancet says life expectancy in China has lengthened dramatically, rising an average of 8.5 years from 1990. Reductions in infectious diseases, diarrhea and infant mortality have delayed premature death.

However, the study said despite the gains in life expectancy seen across China, thought to be linked to increasing GDP and improved maternal education, large inequalities between provinces remain, with life expectancy around 10 years lower for both men and women in some provinces in the western part of China.

Shanghai had the highest life expectancy in China in 2013, at 80.2 for men and 85.2 for women. These figures are comparable to countries such as Japan or France, which have the highest life expectancies in the world, and represent a gain of around six years on the highest life expectancies seen in China in 1990. Big-city dwellers in Tianjin and Beijing have lower mortality and longer life-spans as well.

Moreover, the study reveals striking differences in the leading causes of death in different provinces. Nationwide, cerebrovascular disease (the main cause of stroke) is the leading cause of death for both men and women, and is generally responsible for more deaths in poorer provinces.

“Localized health policies will likely be the key for overall success at the national level,” one of the study’s lead authors, Zhou Maigeng, a deputy director within China’s Center for Disease Control and Prevention, said in a statement.

　The research comes as China’s leaders are mapping out their blueprint for the next five years. And many are urging for more policies and funding aimed at social improvements, such as boosting the health care system, said the Wall Street Journal.