The book deals with the puzzle that although the US is a well-off nation with the world's highest spending per capita on health care, Americans on average live shorter and less healthy lives than their counterparts in many other countries. The book is a sequel to the 2011 National Research Council report ‘Explaining divergent levels of longevity in high-income countries’, which focuses on mortality at ages 50 years and above. To follow up on the investigations, the current report examines mortality and morbidity under age 50, comparing the US against 16 high-income countries that include Canada, Australia and Japan as well as Western European countries. The topics covered in the report are not directly related to pension economics, but they appeal to a broad interest in the levels and differentials of health and mortality.

The book is divided into three parts. Part I (Chapters 1–2) documents mortality and morbidity differences between the US and its peer countries. The US disadvantage is pervasive, existing in multiple health outcomes and affecting all age groups, and has been growing in the past three decades. Nine domains where the US fares worse are listed out: (1) birth outcomes (e.g., low birth weight and infant mortality); (2) injuries, accidents and homicides; (3) adolescent pregnancy and sexually transmitted infections; (4). HIV and AIDS; (5) drug-related mortality; (6) obesity and diabetes; (7) heart disease; (8) chronic lung disease; and (9) disability. The US health disadvantage is not limited to the socioeconomically disadvantaged or uninsured subgroups.

Part II (Chapters 3–8) explores potential explanations of the US health disadvantage by reviewing existing research on the following factors: health care system, individual behaviors, social and economic circumstances, physical and social environmental factors, and policies and social values. Together with the evidence in Part I, the review dispels the widespread perception that the US health care system is the main culprit of its health disadvantage. The US health system is highly fragmented with weak public health and primary care and a large uninsured population, but such inadequacies cannot explain why Americans suffer from higher violent mortality or why the insured rich groups fare worse than their counterparts elsewhere. Unlike the 2011 report that provides numbers on the contributions of specific factors such as smoking and obesity to the US health disadvantage, the book takes a more holistic approach and emphasizes the inter-connections between the sets of factors. Additionally, the book embraces the life-course perspective, emphasizing that risk or protective factors accumulate and interact with each other at various stages of the life course to influence health outcomes.

Part III (Chapters 9–10) proposes future directions for understanding the US health disadvantage. It discusses data needs, methodological development and research funding to meet the challenges. Table 9-1 provides a list of publicly available longitudinal datasets around the world, and showcases the data gaps in various countries. The recommendations not only stress the need for longitudinal data analysis, but also acknowledge the importance of collecting periodic cross-sectional samples so that birth cohorts can be traced over the life course and compared with each other. Data collection emphasizes international collaborations and public data access. As a researcher based in Australia, I noted that the only public dataset for Australia is the Australian Longitudinal Study of Ageing, which does not represent the national population and has a baseline sample of about 2,000 cases only. In addition, to my knowledge, Australia does not have a series of nationally representative cross-sectional samples that are linked with mortality data. Given the limited information collected at death registration, this is a major handicap for health and mortality research in Australia.

Causal language figures prominently throughout the book. The priority given to causal analysis in the search for the causes of the US health disadvantage is somewhat misdirected if, as prescribed by its typical definition in the social, medical and experimental sciences, a causal relationship sustains a counterfactual conditional statement. Take the work on social networks and obesity for example. Causal relations are involved, but a description of the social clustering of obesity is of primary import. In life course research, it is often of interest to examine how a health outcome is shaped by conditions at various life stages. It has been well recognized that in a standard regression analysis it is inappropriate to treat the coefficients for early life factors as effects independent of later life factors, if the latter are affected by the former or the latter as effects if not all early factors are included in the model. Although it is certainly worthwhile to consider alternative research designs such as fixed effects models and instrumental variables to make causal inferences, a descriptive analysis of the process under which individuals are sorted into the various statuses in adulthood would be useful for understanding adult health.

The book is accessible to specialists and non-specialists alike. In fact, the book makes it a priority to alert the general public and start a national discussion about the US health disadvantage. The data sources and literatures it has compiled are rich resources. The research and policy agenda it proposes will be influential in the field of health and mortality in the years to come.