Between 1969 and 2013 in the United States, an overall decreasing trend in age-standardized death rates occurred for all causes (combined) and for the individual causes of heart disease, cancer, stroke, unintentional injuries, and diabetes, a new analysis of vital statistics data finds. However, the rate of decrease has slowed for heart disease, stroke, and diabetes, the researchers say.

"Regardless of the changes in death rates, the increasing numbers of old persons in the U.S. and growth of the U.S. population will pose a considerable challenge for health care delivery in the coming decades," concluded the authors, noting the "shortage of primary care physicians and geriatricians, increasing cost of health care, and the lag between healthy life and life expectancies."

Why Use 'Age-Standardized' Death Rates?

The reason the researchers use age-standardized death rates is because the general population is unevenly distributed across age groups. Since a greater proportion of people over the age of 75 may exist in one year compared to another, crude death rates will not clarify whether more people are dying of a particular disease. (In a year where, say, 30 percent of the population is 75 or older there will be more deaths from age-related diseases than in a year where only 10 percent of the population is 75 or older.) By age-standardizing death rates, then, you can fairly compare one year against another even if the population has different age group proportions over time.

For the study, the researchers updated a previous analysis of time trends for six leading causes of deaths which ran from 1970 through 2002. The study added 11 data years (1969-2013) yet used the same analytic approaches. Additionally, the research team examined trends in years of potential life lost due to premature deaths.

Crunching the numbers the team discovered the age-standardized death rate for all causes combined decreased from 1,279 per 100,000 population to 730 between the years 1969 and 2013. This represents a 43 percent reduction. Five of the six leading causes of death experienced an overall decline in death rates during this time period. For instance, the rate of death (per 100,000) decreased by 77 percent for stroke; by 68 percent for heart disease; by 40 percent for unintentional injuries; by 18 percent for cancer; and by 17 percent for diabetes.

However, the death rate for chronic obstructive pulmonary disease (COPD) increased by 101 percent during this period.

Meanwhile during the same time period, age-standardized years of potential life lost per 1,000 decreased by 14.5 percent for diabetes; 41 percent for cancer; 48 percent for unintentional injuries; 68 percent for heart disease; and 75 percent for stroke. Yet, for COPD, the rate for years of potential life lost did not decrease.In an accompanying editorial, Dr. James McGinnis, an epidemiologist at the National Academy of Medicine, said the report "offers valuable insights on the trends over nearly half a century in deaths from all causes," while noting assessment today requires "more textured insights" with a view to risk prevalence and service access.

Source: Ma J, Ward EM, Siegel RL, Jemal A. Temporal Trends in Mortality in the United States, 1969-2013. JAMA. 2015.