Leading Causes of Death

Figure 10.1 illustrates mortality patterns for non-Hispanic white females in the United States for the years 1999 and 2000. The top row of panels shows the age-specific death rate per 100,000 individuals on a log-log scale. The columns plot all causes of death, death by heart disease, and death by cancer.

The curves for death rate in the top row have different shapes. To study quantitative characteristics of death rates, it is useful to present the data in a different way. The second row of panels shows the same data, but plots the age-specific acceleration of death instead of the age-specific rate of death. The log-log acceleration (LLA) is simply the slope of the rate curve in the top panel at each age. Plots of acceleration emphasize how changes in the rate of mortality vary with age (Horiuchi and Wilmoth 1997, 1998; Frank 2004a).

The bottom row of panels shows one final plotting transformation to aid in visual inspection of mortality patterns. The bottom row takes the plots in the row above, transforms the age axis to a linear scale to spread the ages more evenly, and applies a mild smoothing algorithm that retains the same shape but smooths the jagged curves. I use the transformations in Figure 10.1 to plot mortality patterns for the leading causes of death in Figure 10.2, using the style of plot in the bottom row of Figure 10.1.

Figure 10.2 illustrates the mortality patterns for non-Hispanic white males in the United States for the years 1999 and 2000. Each plot shows

All Heart Cancer

Age

Figure 10.1 Age-specific mortality patterns by cause of death. Data averaged for the years 1999 and 2000 for non-Hispanic white females in the United States from statistics distributed by the National Center for Health Statistics, http://www.cdc.gov/nchs/, Worktable Orig291. The top row of panels shows the age-specific death rate per 100,000 individuals on a log-log scale. The columns plot all causes of death, death by heart disease, and death by cancer. The second row of panels shows the same data, but plots the age-specific acceleration of death instead of the age-specific rate of death. Acceleration is the derivative (slope) of the rate curves in the top row. The bottom row takes the plots in the row above, transforms the age axis to a linear scale to spread the ages more evenly, and applies a mild smoothing algorithm that retains the same shape but smooths the jagged curves. From Frank (2004a).

a different cause of death and the percentage of deaths associated with that cause.

The panels in the left column of Figure 10.2 show causes that account for about one-half of all deaths. Each of those causes shares two attributes of age-specific acceleration. From early life until about age 80, the acceleration in mortality increases in an approximately linear way.

Figure 10.2 Age-specific acceleration of mortality by cause of death. Data averaged for the years 1999 and 2000 for non-Hispanic white males in the United States from statistics distributed by the National Center for Health Statistics http://www.cdc.gov/nchs/, Worktable Orig291. The causes of mortality are based on the International Classification of Diseases, Tenth Revision http: //www.cdc.gov/nchs/about/major/dvs/icd10des.htm. The diseases are: Heart for diseases of the heart; CerVas for cerebrovascular diseases; Accid for accidents (unintentional injuries); Infl for influenza and pneumonia; Suic for intentional self-harm (suicide); Nephr for nephritis, nephrotic syndrome and nephrosis; Sept for septicemia; Canc for malignant neoplasms; ChrRsp for chronic lower respiratory diseases; Liver for chronic liver diseases and cirrhosis; Diab for diabetes mellitus; and Alzh for Alzheimer's disease. From Frank (2004a).

Figure 10.2 Age-specific acceleration of mortality by cause of death. Data averaged for the years 1999 and 2000 for non-Hispanic white males in the United States from statistics distributed by the National Center for Health Statistics http://www.cdc.gov/nchs/, Worktable Orig291. The causes of mortality are based on the International Classification of Diseases, Tenth Revision http: //www.cdc.gov/nchs/about/major/dvs/icd10des.htm. The diseases are: Heart for diseases of the heart; CerVas for cerebrovascular diseases; Accid for accidents (unintentional injuries); Infl for influenza and pneumonia; Suic for intentional self-harm (suicide); Nephr for nephritis, nephrotic syndrome and nephrosis; Sept for septicemia; Canc for malignant neoplasms; ChrRsp for chronic lower respiratory diseases; Liver for chronic liver diseases and cirrhosis; Diab for diabetes mellitus; and Alzh for Alzheimer's disease. From Frank (2004a).

After age 80, acceleration declines sharply and linearly for the remainder of life. Some of the causes of death also have a lower peak between 30 and 40 years.

The panels in the upper-right column of Figure 10.2 show causes that account for about one-third of all deaths. These causes follow steep, linear rises in mortality acceleration up to 40-50 years, and then steep, nearly linear declines in acceleration for the remainder of life. The bottom-right column of panels shows two minor causes of mortality that are intermediate between the left and upper-right columns.

What can we conclude from these mortality curves? The patterns by themselves do not reveal the underlying processes. However, the patterns do constrain the possible explanations for changes in age-specific mortality. For example, any plausible explanation must satisfy the constraint of generating an early-life rise in acceleration and a late-life decline in acceleration, with the rise and fall being nearly linear in most cases. A refined explanation would also account for the minor peak in acceleration before age 40 for certain causes.

All About Alzheimers

All About Alzheimers

The comprehensive new ebook All About Alzheimers puts everything into perspective. Youll gain insight and awareness into the disease. Learn how to maintain the patients emotional health. Discover tactics you can use to deal with constant life changes. Find out how counselors can help, and when they should intervene. Learn safety precautions that can protect you, your family and your loved one. All About Alzheimers will truly empower you.

Get My Free Ebook


Post a comment