WASHINGTON - Health care coverage increased dramatically in parts of China between 1997 and 2006, a period when government interventions were implemented to improve access to health care, with particularly striking upswings in rural areas, a new US research has found.

The research by Brown University sociologist Susan Short and Hongwei Xu of the University of Michigan, appeared in the December issue of Health Affairs.

Led by Xu, the study analyzed data from the China Health and Nutrition Survey, which follows households in nine provinces that are home to more than 40 percent of China's population. Xu and Short specifically focused on patterns of coverage among rural and urban residents.

Their analysis shows that overall, the percentage of individuals in the sample with insurance increased from 24 percent in 1997 to 28 percent in 2004, then rose sharply to 49 percent in 2006. Furthermore, during that period, rural and urban levels of insurance coverage became more similar. Xu and Short call the increase in rural areas "nothing short of dramatic," saying that it likely benefited millions of rural Chinese residents.

"There's been great concern about increasing inequality in China, and particularly urban-rural inequalities," said Short, professor of sociology and faculty associate of Brown's Population Studies and Training Center. "This work shows that at least in one sphere -- health insurance coverage -- urban-rural inequality may be decreasing."

The analysis revealed that levels and trends of health care coverage were significantly different depending on whether the individuals lived in urban or rural areas. In villages, the coverage rates declined from 1997 to 2000, while rates changed little in suburbs, cities, and towns during the same period. Notably, during that time, the government's efforts to establish a new rural insurance program was limited to a few pilot rural counties and did not include financial subsidies for the rural population.

However, after 2000, the coverage rate in villages began to rise, almost tripling between 2004 and 2006, from 17.9 percent to 51 percent. Rates also rose significantly in towns and suburbs during that time frame, but changed only modestly in cities. The dramatic rise in rural coverage rates coincided with the efforts to develop new insurance programs and provide increased subsidies for rural participants.

While the analysis shows higher rates of individual coverage, it also suggests that disparities may persist in the quality of insurance. Xu and Short found that residents of cities, suburbs, and towns experienced higher reimbursement rates for outpatient and inpatient care than insured villagers, indicating that insured urban residents continue to have an advantage over insured rural residents. However, the authors state that these results should be interpreted with caution due to incomplete self-reported reimbursement rates.

The researchers hope that the study will further inform understanding as China strives to improve health insurance coverage for its citizens.