ertheless, the largest divergence among countries appears to have been for women aged 50 and over, and this segment of the population has been the primary focus of this report.

Descriptive analysis can be a powerful tool in demography. In this case, the panel undertook a careful examination of cause-of-death statistics to ascertain whether specific causes of death could account for the relatively low level of life expectancy in the United States and were associated with improvements in life expectancy in vanguard countries. Comparative analysis of causes of death is complicated by issues of variation in coding practices across countries and over time. Nevertheless, it does appear that higher mortality rates for lung cancer and respiratory diseases in the United States, Denmark, and the Netherlands are an important part of the story. Such a finding is clearly consistent with the hypothesis that smoking was an important factor accounting for the slowing of mortality decline among women in these three countries.

Other conditions that account for the poor performance of U.S. women include cerebrovascular conditions (primarily stroke), diabetes, and mental disorders. Stroke is another cause of death for which smoking is a risk factor. Obesity is a risk factor for both stroke and diabetes. With respect to mental disorders, the increase in such disorders is difficult to interpret, and the idea that this increase is attributable to differences in coding cannot be rejected. It should be noted, however, that the risk factors for heart disease, diabetes, and stroke overlap with those for Alzheimer’s disease, and it is possible that the trend in deaths due to mental disorders is related to some of the same underlying factors. Although mortality from heart disease played little role in the divergent trends in life expectancy—because even 50 years ago the United States already had much higher levels of mortality from heart disease than the other countries examined for this study—it accounts for about half the current gap between the United States and the countries with highest life expectancies; therefore, this condition should be a focus of efforts to bring U.S. life expectancy in line with that of the exemplar countries.

While descriptive analysis of causes of death is certainly informative, this report has begun the process of moving from description to identifying the underlying determinants of the observed differences, a necessary first step toward ultimately developing an integrated model of causal processes. More specifically, the panel examined a number of possible risk factors and considered how differences among countries in exposure to these risk factors might account for observed disparities in improvement in life expectancy. Such an approach is not without its limitations. For some factors, comparable cross-country data exist on the current levels of risk, while for others, surprisingly little direct evidence can be brought to bear. Few countries are conducting systematic surveillance of health risk factors, so that directly comparable data even for the present often are not available for a large



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