Vitetta and Anton causes of mortality and that numerous lines of evidence indicate that environmental factors are the most important in determining disease prevention. Hence, environmental factors may certainly have the strongest inﬂuence on life expectancy and hence lifespan (Figure 1) (Willett 2002; Vitetta et al 2005). Intertwined with nutritional practices and lifestyle is life stressor modiﬁcation (Vitetta et al 2005). Evidence continues to accumulate that strongly suggests that the state of a human being’s mind – which associates psychosocial factors with emotional states such as depression and with behavioural dispositions that include hostility and psychosocial lifestyle stresses – can directly and signiﬁcantly inﬂuence human physiologic function and, in turn, health outcomes. Stressors and negative stress-related reactions have been documented and recognized to have multiple ill health related sequalae and exposure to chronic social stress has been associated with many systemic and mental disorders. These have signiﬁcant deleterious outcomes that signiﬁcantly decrease life expectancy (Ader 2003; Vitetta et al 2005). Different research groups support the notion that health consequences are more likely to occur when unpredictable stressors of a social nature chronically induce physiological and behavioral adjustments that may create wear and tear on underlying physiological functions. When stressors challenge an organism’s integrity, a set of physiological reactions is elicited to counteract the possible threat and adjust the physi- ological setting of the organism to the new situation. This has become known as the stress response (Ader 2003). Stresors and lifestyle choices can be a signiﬁcant trigger for disease through immunomodulation of the immune system enhancing disease susceptibility, which can then affect life expectancy (Ader 2003). Immune function modulation inﬂuenced and expressed by stressful life experiences has a signiﬁcant s e s a C e l b a t n e v e r P t n e c r e P 100 90 80 70 60 Diabetes Type II CHD Stroke Colon Cancer Chronic Disease Type Figure 1 Preventable chronic diseases.Adapted and modiﬁed from Willett 2002. 538 Clinical Interventions in Aging 2007:2(4)