One of the most appealing scientific challenges in epidemiology is to understand the socioeconomic gradient of health [1, 2]. Explaining the gradient is not a mere scientific undertaking, but also a policy issue. In a time of rising health inequalities policy makers, whether driven by public pressure or a gen uine interest, are increasingly asked to develop poli cies reducing the health gap. Assuming that governments were ready to take policy action to confront inequalities, they still face a crucial question: what are the factors responsible for the socioeco nomic gradient of health? Two major mechanisms have been proposed to explain the gradient: material deprivation and psy chosocial disadvantage. Such mechanisms comprise the most important health determinants including socioeconomic factors, the social and physical environment, healthcare and social services, and health behaviours [3]. The former focuses on the lack of tangible resources and systematic underin vestment across a wide range of human, physical, health and social infrastructures (e.g. food, housing, health services, transportation, environmental quality, and occupational health) [4]. The latter emphasizes perceptions of place in the hierarchy translated "inside" the body as negative emotions, "outside" the individual into antisocial behaviours (e.g. homicides), reduced civic participation and social cohesion, and stress-induced behaviours (e.g. smoking) [5]. Although both mechanisms contribute to explain population health variations [6], large gradients, however, are found even in societies with favourable circumstances in terms of health deter minants and health status [7]. An interesting case comes from Trentino Alto-Adige, one of the wealthiest, healthiest, egalitarian and socially cohe sive regions of Italy and the industrialised world. Within Italy, Trentino ranks at the top of a com posite score of health determinants (Table 1). De spite this advantaged position and the very high longevity, a large gradient is still found within Trento, one of the two provinces of the region (Figure 1). Health behaviours such as smoking are com monly cited to explain the gradient [8]. Indeed, health inequalities are strongly related to socioeco nomic variations in mortality rates in cardiovascu lar diseases and such differences can be plausibly attributable to healthier behaviours among the most privileged groups. However, can health behaviours be the culprit for the large gradient of Trentino? It is hardly so. Trentino shows a pattern of inequalities similar to other areas in Southern Europe that present flat or even positive gradients of smoking [9]. What else can explain the gradient in healthy societies such as Trentino? Certainly, today's health inequalities have been affected by changes in health determinants in the past. However, the gradient is consistent across different age categories (data not shown). Moreover, Trentino has been wealthy, heal thy, egalitarian and socially cohesive for a long time and its policies should have had sufficient time to improve population health and reduce health inequalities. They certainly did the former, but not the latter. The policies implemented in the region are to be applauded and encouraged given the impressive achievements in terms of health and quality of life. Even so, Trentino continues to present a pervasive socioeconomic gradient of health. For scientists, the reduction of the gradient remains a puzzle. For policy leaders, it is an overwhelming policy objective. Rather than being explained by downstream factors such as smoking, the gradient seems to be rooted in the upstream structural and institutional inequalities of society. Policy mecha nisms buffering the lowest socioeconomic groups from inequalities in material, psychosocial and behavioural disadvantage will probably contain the gradient. Nevertheless, unless a transformation of the structure and organizing principles of our society is undertaken, the gradient will not be eliminated.