An undated photo shows an elderly woman dining at a nursing home in Hangzhou. [Sun Yidou/For China Daily]

It is estimated that China's aging population will reach its peak of 400 million by 2055, with large numbers of the elderly in rural areas and a prevalence of female senior citizens, a recent report showed.

The report, issued by Social Science Academic Press, pointed out that the Chinese aging population, defined by an age threshold of 65, is expected to climb to 280 million by 2030, accounting for 20.2 percent of the population. The number will further jump to 400 million by 2055, with an accompanying percentage of 27.2 percent.

The years before 2040 will witness the fastest growth of the elderly population, with an annual growth of 0.5 percent. The population's disproportionate female population is due to the longer average life expectancy of women compared to men, the report added.

Generally speaking, the larger a city is, the more slowly its population will age. However, compared with developed countries like Japan and Korea, population-aging in China has its own characteristics.

"The aging population in Japan and Korea is a natural result of transitioning economic development, while the phenomenon in China is largely due to family planning policies, which led to a decrease in births," noted Ma Li, a population expert and State Council counselor.