Osteoporosis, the most common metabolic bone disease, is a major health problem throughout the world. Osteoporosis is exclusively women's disease and its prevalence increases as population ages. Primary osteoporosis, one of 2 broad categories of osteoporosis, has been divided traditionally as type I postmenopausal and type II senile osteoporosis according to menopausal states and ageing process. Therefore demographic survey on certain society or nation seems to be the fundamental for the epidemiological study of osteoporosis.

The elderly population of Korea has been rapidly growing. The elderly comprised 3.1% of total population in 1970. Now in 2015, it is increased up to 13.1%. The female life expectancy in Korea is 84.6 years, 6.8 years longer than male in 2015.[1] As growing elderly population, the population of old women will be also increasing.

In this year of 2015, the Korean total population is 50.62 million with 25.31 million female population. From this year, female population exceeds the male population. The number of aged 65 and over is 6.62 million, composed of 13.1%. The population of women aged 50 and over, that seems to be menopausal, is 9.31 million, comprising 36.8% of total female. The proportion of women aged 50 to 64 years is 21.5% and 65 years and over is 15.2%.

As growing of old women population, menopausal women will also increase. Estimation of postmenopausal population is essential information for health care providers, especially gynecologists, endocrinologist and geriatricians.

But there has been no clear demographic information about postmenopausal and elderly geripausal population. The aim of this study was to survey the demographic changes of 1) Korean women, 2) postmenopausal women, and 3) elderly geripausal women using Population projection 1960-2060 from Korean Statistical Information Service (KOSIS).

We use population projection 2010-2060 from KOSIS published in 2011. Population projection is made basis of population and housing census 2010. Average annual increase rates and cumulative increase are used for change of population. The average annual increase rates are calculated on the assumption that growth is continuous. The cumulative increase is calculated rate of increase and decrease basis of population of 2000.

According to our survey on demographic changes in Korea, total population, will be peak in 2030, reaching 52.16 million in number. By 2030, one out of 2 women will be postmenopausal & nearly 1 out of 4 women will be geripausal. The postmenopausal population will reach about 22.19 million in number by 2060, comprising nearly 60% of all female and the elderly, geripausal population will be 9.42 million in number, comprising 43% of all female.

The greying of Korea is accelerating due to low birth rate and increased life expectancy. The ageing rate of Korea is faster than that of developed country. Korea has already been an aging society since 2000. After only 26 years, Korea will become a super-aged society through aged society in 2018.[4]

According to reports from 2013 United Nations,[5] ageing is worldwide phenomenon. The cause of ageing is decreasing mortality and decreasing birth rate. The relative decrease in the youth population due to reduced fertility is most important cause. World population over 60 years increased 9.2% in 1990 to 11.7% in 2013. And it will increase 21.1% in 2050. The old women are living longer than the old men and it is universal feature.[6] The world is going to small, old and female society.

Some developed countries, such as Germany, Italy, and Japan had already over 20% of elderly, in 2012. Until 2030, elderly proportion is projected to increase in all developed countries. In 2030, one third of Japanese will be elderly (32.2%). In USA, elderly population was 43.1 million in 2012, and it will expected almost double in 2050, as 83.7 million.[5]

As getting older, there are many changes in body composition and hormonal regulation system to maintain homeostasis. The declined hormonal function influences end organs. The elderly people are susceptible to disease because of poor adaptation.[7] According to the report from Korea National Health and Nutrition Examination Survey, one in four old people have restriction on daily life due to Health problem or disability.[8]

Mean age of menopause In Korean women is 49.7 years. Menopausal age is similar to other countries. For instance, 50 years is mean menopausal age in the USA, 48.6 years in Australia and 49.0 years in Singapore.[9] As life expectancy of women is longer, women live about 30 years after menopausal state. By 2030, postmenopausal women will be half of the entire Korean women. Even more in 2060, the number of postmenopausal women will outnumber. Therefore Health care for postmenopausal women will be most important issue for health care providers.

Low estrogenic state cause many health problems. Vasomotor and psychological symtoms are early menopausal symptoms. Followed symptoms are urogenital atrophy, skin ageing from collagen loss, myalgia and arthralgia. Chronic sequelae are osteoporosis, cardiovascular disease (CVD) and senile dementia.[10]

Estrogen plays an important role in bone formation and maintaining bone. So bone loss is accelerated after menopause. The rate of bone loss is maximal during the first 5 years and may be 3-5% annually. The rate begins to decrease 10 years after menopause but continues throughout the postmenopausal years. There are two aspects of osteoporotic fracture, one is crush fracture syndrome occurs 55 to 65 years, called postmenopausal osteoporosis. The other is hip fracture occurred in elderly person, called senile osteoporosis. Osteoporosis and osteoporotic fracture are associated with morbidity, mortality and high socio-economic costs. Osteoporosis is rising health problem in ageing society.[11]

In USA, 30% of postmenopausal women have osteoporosis and about 50% have osteopenia. As getting older, prevalence of osteoporosis is increasing. At the age of 80, 27% have osteopenia and 70% have osteoporosis. Life time risk of osteoporotic fracture is 39.7% in women and 13.1% in men.[12] About 38% of Chinese women and 31% Japanese women aged 50-79 years have osteoporosis.[13] According to Korea National Health and Nutrition Examination Survey, reported prevalence of osteoporosis of Korean men and women older than 50 years is 7.5% and 37.5%, similar to the western. Classifying by age group, prevalence of osteoporosis in women is 15.5%, 36.6%, and 68.7% in 50's, 60's and over the 70's respectively, compared with 3.5%, 7.5% and 18.0% in men.

Osteoporosis increases the risk of fracture especially in vertebra, hip and wrist. Hip fracture is associated with high mortality and morbidity.[14,15] Osteoporotic fracture in the US is about 2 million cases. Seventy-two percent of Medicare budget for fracture was associated with osteoporotic hip fracture. This cost will be rising to 253 billion in 2025.[15] In Korea, 3 of 4 osteoporotic patients did not know morbid state and only one in ten patients was on medication for osteoporosis.[16] Health providers for elderly people needs more concern for prevention, education and treatment of osteoporosis.

CVD is leading cause of death in western society.[10] In Korean women, CVD is third cause of death.[17] Because women's CVD is increased after menopause, increased incidence of CVD is seen women after 50's compared with increase in men in 40's.[18]

Dementia is most common cause of disability in elderly person. Women are higher risk for developing dementia than men. The prevalence and incidence of dementia is tend to higher in postmenopausal women because of longer life expectancy of women and long term effect of estrogen deficiency.[18] The prevalence of dementia among Korean elderly people is reported as 9.18% in 2008 and it will increase 9.61% in 2030, followed by 13.17% in 2060.[19,20]

Women over 65 years encounter not only postmenopausal changes but also changes from ageing. Eskin and Troen [21] first proposed the term 'geripause' for postmenopausal women over 65. He insisted that geripause can be divided into early, 65 to 85, and late, 85 and over. Geripausal women go through a lot of changes from ageing rather than menopausal changes. After 65 years, gonadotropin begins to decrease and estrogen level is lower than early menopausal level. Clinically, menopausal symptom such as hot flush, urogenital atrophy, mood change improved slightly. Instead, other endocrinologic changes are occured such as thyroid function abnormality, impaired glucose tolerance and adrenal impairment. Therefore geripausal women need new environmental and medical settings, such as diet adjustment, regulation of medication dosage, multidrug use, and new laboratory standards.[21,22]

In contrast of decreasing of total women, geripausal women will increase continuously during the next 45 years in Korea and, the number will be more than double. Average annual increase rates of late geripausal women are 5.2%, suggestive of the fastest growing population. In 2060, four of Korean women will be geripausal and one of menopausal women will be late geripausal. Therefore we needs more concern about geripausal change and manage for geripausal women.

In conclusion, in the year of 2060, six of ten women will be postmenopausal and seven of ten postmenopausal women will be geripausal. As expected to increase proportion of elderly women, dramatic rise of osteoporosis and osteoporotic fracture also expected. Health providers pay more attention to postmenopausal and geripausal women health care. For adequate care of osteoporosis, collaboration of primary physician and specialist in bone metabolism will be essential. We urgently needed the adequate strategies against rapid aging of our Korean society at moment.