Antiaging from a Demographic Perspective

Demography, or population statistics, is a field of study that focuses on changes and fluctuations in population. In a narrower sense, it refers to the field that quantitatively analyzes the state and changes of the population at a certain point in time [1]. Amid the outcry of a declining birthrate and aging population, Japan’s population experienced its first post-war decrease in 2005, and has been declining since its peak of 128.08 million in 2008 [2]. Many people may have seen predictions about Japan’s future population, such as “Japan’s population will drop below 50 million by the twenty-second century (2101)” [3]. These estimates are calculated by determining the changes that occur with aging in the population by age, for each related factor (death, birth, population movement). Even if unprecedented disasters, economic crises, or wars occur, it can be said that there have been few instances where future population estimates, which are estimated with a range of scenarios from optimistic to pessimistic, have been off. For example, in a long-term series of articles titled “Alarm from 2020” published in the Nihon Keizai Shimbun on New Year’s Day 1997, future predictions were made for various fields such as economics, finance, education, and environmental issues, but there were hardly any that were significantly off based on future population predictions [4]. There are several methods used for future population predictions, but here we will briefly introduce the “cohort component method”. In the cohort component method, the future population is determined by considering deaths that occur with aging and international population movements (outflows) for the existing population. For the population that increases due to births, etc., the number of births and population movements (inflows) according to the reproductive age population are incorporated as the population for the next year. To calculate this, it is necessary to make assumptions for the future based on ① the standard population classified by gender and age, ② birth rate, ③ survival rate, and ④ international population movement rate [5]. Specifically, for example, for ② birth rate, estimates are made for the distribution of first marriage age, the unmarried rate at age 50, the number of completed births (the average number of births at the wife’s age of 50 in a first-marriage couple), and the effect of divorce/death/remarriage on the number of completed births, and in some cases, multiple optimistic/pessimistic scenarios are set and multiple estimates are made based on statistical mathematical models [5]. Of course, when estimating the future population, the trend of the average lifespan, which has been somewhat leveling off in recent years, is taken into account (Fig. 161.1). Consideration has been given to the extension of life expectancy, with certain assumptions in place, but there seems to be no consideration of the factor of “anti-aging”. As mentioned above, in order to increase the birth rate [2], a Child and Child-rearing Headquarters has been established and extraordinary measures against declining birth rates are being implemented, and there is a lot of reaction to the news about this in the public, but considering that the second baby boom generation (baby boom junior generation) is already around 50 years old, it is unlikely that this will have a direct impact that would affect demographic assumptions and necessitate further revision of optimistic scenarios. Therefore, from a demographic perspective, if we want to maintain the future population, the options left are to increase the survival rate [3] and the international population migration rate [4]. For [4], a shift in immigration policy based on data is necessary, and there are strong concerns about the impact on society, but if the effect of stopping the decrease in the existing population by the penetration and spread of anti-aging medicine increases, it will be possible to contribute to [3] without significantly changing the social structure from a policy perspective, so the expectation for anti-aging medicine is high from the perspective of maintaining the future population. Also, it goes without saying that careful discussion and accumulation of evidence are necessary for various risks associated with late childbirth, but the age at which pregnancy and childbirth are possible may be raised by anti-aging medicine, and anti-aging medicine may contribute to the birth rate [2] to a significant extent. In addition, while demography considers the “population” purely in terms of numbers by considering births and deaths, it is highly likely that anti-aging medicine will also affect the extension of so-called healthy life expectancy, not just the extension of survival time. Specifically, in considering the sustainable maintenance and development of society, how to reduce the burden of the population onus period [populationonus]. A period when the proportion of the working population decreases compared to the population of children and the elderly, and the economic burden increases. The opposite of the “population bonus period” when the productive age population (15 to under 65) is more than twice the rest of the population] that Japan has already entered is a problem in various situations. By extending the time that one can engage in social activities in good health, it is possible to put a brake on the actual decrease in the working population, and anti-aging medicine may have the potential to reduce the various economic burdens that will increase during the population onus period, such as the increase in social security costs. It should be noted that while the productive age population is defined purely by age, the working population refers to people over the age of 15 who have the intention and ability to work, and there is no upper age limit. Although accurate surveys are difficult, it is thought that the greatest contribution that anti-aging medicine can make from a demographic perspective is the maintenance and increase of this working population. This section has discussed the expectations and possibilities of antiaging medicine from a demographic perspective, but “living healthily in mind and body” is a common wish for all people. The classification of primary prevention (prevention of disease occurrence), secondary prevention (early detection, early treatment, and prevention of severity), and tertiary prevention (restoration of function, social return, and prevention of recurrence) has been established for diseases, and there has been a long-standing emphasis on prevention. Anti-aging medicine can contribute to all of these stages, and it is hoped that it also has the potential to prevent causes and factors related to diseases, which could be called zero prevention.