Aging successfully and healthfully

The vast market of anti-aging products from skin serumsto ingestiblesupplementshighlights thewidespread interest in maintaining youthful appearances and energy levels.Whilefighting age-related changes is difficult, if not impossible at the present time, there is growing interest in learning how to embrace aging in a healthful manner – i.e., how to age successfully. Clearly, oneof thecorequestions in thisquest is,what exactly constitutes successful aging? The 2006 review by Depp and Jeste set out to examine the differing definitions of successful aging presented in the scientific literature (Depp and Jeste, 2006). Most commonly, policymakers and researchers have used Rowe and Kahn’s model – living without disability and maintaining high levels of cognitive, physical, and social functioning (Rowe and Kahn, 1987; 1997). Indeed, Depp and Jeste found that nearly 90% of the studies reviewed had used a lack of physical disability and/or unimpaired physical functioning as the benchmark for successful aging. Modern medical innovations have increased longevity over the past century, yet it is not clear that people are also aging more successfully in terms of physical and cognitive functioning. There are studies reporting rising rates of dementia. Perhaps it is time to shift our focus to other facets of aging. Some studies have defined successful aging using measures of well-being, e.g., life satisfaction, happiness, social engagement, and positive personality traits such as resilience, optimism, and selfefficacy. These understudied positive constructs may be better markers of successful aging than physical functioning. Three studies in this issue of International Psychogeriatrics focus on important aspects of successful aging, beyond avoidance of physical disability and disease. First, Martin et al. (2019) present a unique comparison of populations with exceptional longevity— centenarians living in theUS and Japan. The US centenarians had better cognition and were more likely to have hypertension, heart disease and myocardial infarction compared to the Japanese centenarians.While strokewas associatedwithworse cognitive functioning, hypertension was associated with better cognitive functioning. Furthermore, the relationship between heart disease and cognitive functioning differed in the two populations, i.e., heart disease was associated with worse cognitive functioning in the US and better cognitive functioning in Japan. As eloquently discussed in the Commentary byFlint andBingham, longevity is only 25% heritable, and is largely subject to environmental and behavioral influences including exercise, diet, and positive psychological traits (Flint and Bingham, 2019). Also, the paradoxical relationship between cognition and blood pressure in centenarians has important clinical implications for this subpopulation, as we strive to personalize medical care for each individual. Next, Fung et al. (2019) examines loneliness in older Chinese adults and the links with different types of relationships and cognitive functioning. Loneliness is an important social aspect of successful aging, with a number of studies emphasizing its influence on mental and physical health (Aanes et al., 2011; Boss et al., 2015; Cacioppo et al., 2002; Tabue Teguo et al., 2016; Yu et al., 2016). While exploratory, the findings from the Fung et al. paper indicate that the interaction between loneliness and a non-confiding social network (i.e., the participants did not feel they could express their inner feelings with their social contacts) were significantly associated with poor cognitive functioning. The authors reported that these interactions were significant for non-confiding family networks (as opposed to nonconfiding friend networks), which may reflect the cultural importance of family unity among this population of Chinese adults living in Hong Kong. As aptly described in the Commentary by Palmer, social isolation is distinct from loneliness, and the cognitive effects of the interaction between loneliness and social network size and quality have not been examined previously (Palmer, 2019). Palmer also noted how the Fung et al. article takes much neede first steps toward empirical and conceptdriven research on loneliness to aid policymakers and clinicians in understanding the interrelations and consequences of loneliness and social isolation, and personalizing and targeting interventions for this growing social epidemic. Last, Ardelt and Ferrari (2019) examine the relationships between wisdom and well-being, specifically the mediating roles of mastery and purpose in life. Religiosity was also found to be associated with well-being. The authors compared a younger (ages 21–30 years) and older (ages 62–99 years) International Psychogeriatrics (2019), 31:4, 439–441 © International Psychogeriatric Association 2019