| 49 Health Behaviors Health behaviors are considered sociocultural influences since these behaviors are acquired through socialization and are highly related to education ( Markus et al., 2004 ). Substantial similarity in health behaviors across generations within families has also been reported (cf. Maitland, 1997 ). Self-regulatory health behaviors also differ markedly across ethnic and racial groups (cf. Jackson & Knight, 2006 ). The impact of health behaviors such as exercise, smoking, and alcohol consumption on maintenance of cognitive ability has been mixed ( Anstey & Christensen, 2000 ). Colcombe and Kramer (2003) reported fitness effects to be selective with aerobic fitness training having a greater positive impact on tasks associated with executive control. In the MacArthur successful aging study ( Albert et al., 1995 ) strenuous daily physical activity was a significant predictor of positive cognitive change. There is a paucity of studies on cigarette smoking and cognition. A systematic review found decreased AD risk in case- control studies but increased risk in prospective cohort studies ( Kukull et al., 2002 ). Obesity has been associated with atherogenesis, hypertension, and diabetes and was found to increase risk for cognitive decline or AD (Sarkisian, 2000). More recent studies indicated that a U- or J-shaped curve may describe the relationship between level of alcohol use and cognitive functioning
( Hendrie et al., 1996 ). Some studies find the association between cognition and moderate drinking stronger for women than for men. The MIDUS midlife study found educational differences in health behavior practices with college educated reporting a higher rate of exercise and lower rates of smoking ( Markus et al., 2004 ), suggesting positive cohort trends in health behaviors. Support for healthier lifestyles appears also to be offered by participation in religious communities ( Krause, 2008; Schaie et al., 2004 ). More recent cohorts of elderly have also experienced increased access to activities and resources that provide healthier lifestyles and better healthcare cf. Schaie & Pietrucha, 2000; Schaie et al., 2003 ). The evidence seems clear that historical trends in extending preventive health practices and positive lifestyle changes have led to substantial health benefits for successive generations of elderly individuals (cf. Leventhal et al.,
2008; Schaie et al., 2002 ). A large number of laboratory studies that showed the effectiveness of cognitive training interventions to slow cognitive decline in the elderly have now reached the level of clinical trials (e.g., Willis et alb THE ROLE OF IMMIGRATION Particularly in view of the dramatic decline of the American fertility rates in recent cohorts, the role of immigration has once again increased in importance in determining our society ’ sage structure, as well as determining many characteristics of the aging population DeJong, 2005; Fuligni, 2005; Gibson & Lennon, 1999; Rumbaut, 2005; Treas & Batalova, 2007 ). The recent interest in projecting the proportion of elderly immigrants as well as the aging of the immigrant of the American populations has led to some interesting conclusions. First , it appears that current projections of the for- eign-born population represent underestimates of the proportion of foreign-born within the elderly populations. Second, immigrants in general and older immigrants in particular contribute to the increasing racial and ethnic diversity in American society. Third, social and cultural incorporation of older immigrants appears to be a function of the length of time they have spent in the United States. Hence relatively recent older immigrants tend to be disadvantaged as compared to immigrants who have spent a major portion of their lives in the United States ( Hirschman,
2007 ). They are less likely to be fluent in English, are less likely to live in homes they own, and they have much lower incomes. On the other hand, long-term immigrants are more similar to their native-born counterparts (cf. Treas & Batalova, 2007 ).