摘要：Objectives. We reviewed literature on comparative social policy and life course research and compared associations between health and socioeconomic circumstances during an 11-year period in the United States and the United Kingdom. Methods. We obtained data from the US Panel Study of Income Dynamics and the British Household Panel Survey (1990–2002). We used latent transition analysis to examine change in self-rated health from one discrete state to another; these health trajectories were then associated with socioeconomic measures at the beginning and at the end of the study period. Results. We identified good and poor latent health states, which remained relatively stable over time. When change occurred, decline rather than improvement was more likely. UK populations were in better health compared with US populations and were more likely to improve over time. Labor market participation was more strongly associated with good health in the United Kingdom than in the United States. Conclusions. National policies and practices may be keeping more US workers than UK workers who are in poor health employed, but British policies may give UK workers the chance to return to better health and to the labor force. The cause of poorer health of the US population compared with that of other developed nations has been much debated in recent years. 1 – 3 Some suggest that differences in population health stem from restricted access to resources at the individual level and public underinvestment in the human, physical, and social fabric of society within countries, including health and welfare policies. 4 The more generous, comprehensive, and universal state programs of social democratic welfare governments have already been compared with the more financially limited and less accessible programs in the United States. 5 – 7 Yet, despite these insights, at least 2 significant issues remain relatively unexplored in comparative research on socioeconomic inequalities in health. First, most comparative work on health differences has focused on aggregate measures of inequality. 8 – 11 However, if we are to better understand how policies contribute to, maintain, and reduce social inequalities in health, we need between-country comparisons of health and inequality at the individual level. A second issue is that most comparative research relies on cross-sectional data 12 – 14 despite widespread acknowledgment that socioeconomic conditions and health have a complex time-dependent relationship 15 and analysis of this relationship requires longitudinal repeated-measures data. For example, recent research on individual health change or trajectories shows that health patterns are more variable than previously thought. On average, physical health and function may decline with age, 16 but there is considerable individual variation in this overall pattern. 17 – 20 This suggests that the population health disadvantage in the United States at one point in time may tell us very little about national differences in health across individuals’ life courses. Because health has stable and dynamic components, we investigated patterns of population health over time within a given country and differences in these patterns between countries. This approach also allowed us to make stronger statements about the social causes and consequences of different health patterns. We compared health trajectories and their associations with socioeconomic variables in the United States and the United Kingdom during the 1990s. The United Kingdom is an interesting comparator because, like the United States, it is considered to be a liberal welfare state, 21 , 22 although some of its policies are more closely shared with European social democratic welfare states. Recent UK welfare reforms resemble the means-testing and welfare-to-work programs that now dominate the US social assistance agenda, but the provision of universal health care and child benefits in the United Kingdom are just 2 examples of important differences in agendas. 23 Furthermore, although poverty rates in the United Kingdom and the United States were higher throughout the 1990s compared with the Organisation for Economic Co-operation and Development average, the United Kingdom ranked squarely alongside other European countries in lifting those at risk out of relative income poverty via tax and benefits systems. 24 , 25 During the 1990s, however, there was convergence between US and UK welfare reforms. 15 Although we did not test specific hypotheses associated with this development, the reform period provides the context within which we interpreted population health patterns in the 2 countries and some possible causes for these patterns. When comparing health trajectories, we asked 2 questions: what are patterns of individual health change in the United States and the United Kingdom, and how are these patterns associated with antecedent and subsequent socioeconomic circumstances? We used data from the US Panel Study of Income Dynamics (PSID) and the British Household Panel Survey (BHPS) to investigate individual health patterns with a latent transition model. 26 This approach built upon earlier work in which we modeled individual growth curves as a continuous function of self-rated health over time. 27 , 28 However, health trajectories may be better represented as movement between discrete stages that involve not only stable periods or unidirectional change but also intermittent deterioration or improvement. We asked whether and how health changes during an 8-year period, and whether the reciprocal association between health trajectories and socioeconomic circumstances over time can inform us about the processes that underlie cross-sectional national differences in health.
