The Smoking-Attributable Mortality (SAM) computation page allows you to edit the data elements used to compute annual SAM and SAM rates by disease category and sex.

For a detailed description of the methods used to calculate SAM and SAM rates, refer to Methodology. 

(Optional) To determine the SAM rate:

• Repeat steps 1 through 3.
• Review the selected population data. Click the Back button on your browser to return to the computation page.
  To change the data selection, click Edit Selected Population Data.
• Review the standard population data. Click the Back button on your browser to return to the computation page.
  To change the data selection, click Edit Standard Population Data.
• Display the Smoking-Attributable Mortality Rate Report by clicking on the Annual SAM Rate Per 100,000 link.

Smoking-Attributable Mortality
To calculate SAM, you must calculate the smoking-attributable fraction (SAF) using current and former smoking prevalence estimates for adults 35 years of age and older and the relative risk data. For each smoking-related disease, multiply the disease-specific number of deaths for each sex-specific 5-year age category by the SAF for that group. 

SAM = Number of deaths X SAF 

To determine the overall sex-specific SAM estimate for each disease, add the disease-specific estimates for each age category within each sex, and to determine the overall SAM estimate for each disease, add the sex-specific estimates.

The SAF is the proportion of deaths causally linked to cigarette smoking. Calculation of the SAF requires two other measures: disease-specific relative risk estimates and smoking prevalence estimates.

Relative risk is the ratio of the mortality rate for exposed persons compared with that for non-exposed persons. For cigarette smoking, the relative risk is the ratio of the mortality rate for current or former smokers compared with that for those who have never smoked: 

Relative risk = Mortality rate for current or former smokers / Mortality rate for never smokers

An expanded form of the attributable risk formula accounts for differences in exposure levels between current smokers and former smokers as indicated by separate prevalence estimates and relative risk estimates. This formula is used to calculate the total SAF by sex for each disease for the population under study. 

SAF = [p0 + p1(RR1) + p2(RR2)] - 1 / [p0 + p1(RR1) + p2(RR2)] 

• p0 is the percentage of those who have never smoked in study group. 
• p1 is the percentage of current smokers in the study group. 
• p2 is the percentage of former smokers in the study group. 
• RR1 is the relative risk for death among current smokers compared with that among those who have never smoked. 
• RR2 is the relative risk for death among former smokers compared with that among those who have never smoked.

Smoking-Attributable Mortality Rate
SAMMEC calculates age-adjusted SAM rates for persons aged 35 years and older. These rates were standardized to the age distribution of the United States population in 2000, typically referred to as the Year 2000 Standard Population (see Klein and Schoenborn, 2001).

The crude death rate defined as the total number of deaths divided by the population is often used to express mortality risk. However, since the risk of dying increases with age, populations with older age distributions will tend to have higher crude death rates. As a result, when one compares crude mortality rates across groups (e.g., states) one cannot be sure whether differences are due to differences in the age distribution between groups or to differences in mortality risk. Age-adjustment is a statistical technique designed to reduce differences in crude rates that result from differences in populations' age distribution.

Age-adjusted SAM rates were estimated using a method suggested through correspondence with RN Anderson (see Anderson and Rosenberg, 1998). First, the crude death rates by sex and five-year age category were calculated. Second, the standard weights were calculated by dividing the standard population estimates by sex and five-year age category by the total standard population aged 35 and older. Third, the age and sex specific crude rates were multiplied by the standard weights and summed over age for males and then for females to get age-adjusted SAM rates by sex. The total SAM rates (for both sexes) were obtained by multiplying the age specific crude death rates by the standard weights and summing over age. The age-adjusted rates are expressed per 100,000 population.

MCH SAMMEC has a single age category. Therefore adjusting the rates to a standard population is not necessary.