What does the population attributable fraction mean?

How do you interpret population attributable fractions?

Interpretation. Attributable fraction for the population combines both the relative risk of an incident with respect to the factor, as well as the prevalence of the factor in the population. Values of AFp close to 1 indicate that both the relative risk is high, and that the risk factor is prevalent.

What is the meaning of attributable fraction?

Attributable fractions (AFs) are measures of association between a disease and a specific exposure that attempt to assess the public health impact of that exposure.

Why is population attributable fraction important?

The population attributable fraction (PAF) is a very useful measure for determining health priorities for intervention [1]. PAF has a causal interpretation, defined as the fraction of cases that would have not occurred if the exposure had been eliminated [2,3].

How do you interpret population attributable risk percentage?

Calculating the population attributable risk percent allows you to determine what percent of an outcome could possibly be prevented if a risk factor were to be removed from the population. To calculate the attributable risk, one simply subtracts the risk for the non-exposed group from the risk for the exposed group.

What is the fraction of cases with the disease among the exposed that is attributable to the exposure?

Attributable Proportion Among the Exposed

It is calculated by taking the risk difference, dividing it by the incidence in the exposed group, and then multiplying it by 100 to convert it into a percentage.

Can attributable fractions negative?

The attributable fraction ranges from -∞ to 1, although negative values are commonly transformed to the preventable fraction, in which “no exposure” is replaced by “exposure” in the first formula (Last, 1983).

How do you find the attribute of a fraction?

1) calculate the AF for specific cancers 2) use the AF and the total number of cancer cases to determine the number of cases which would be avoided if exposure were eliminated, for each cancer 3) add the avoidable cases together across all cancers 4) divide the avoidable cases by total cancer cases to get all cancer AF …

What is population attributable risk example?

Often, attributable risk is given as a percentage (called the attributable risk percent or AR%). For example, lung cancer has many causes, including smoking cigarettes and exposure to indoor radon. One study showed that the AR% for cigarette smoking and lung cancer was 85%.

How do you calculate population attributable risk par?

It is the incidence of the disease in the population that would be eliminated if exposure were eliminated. PAR is computed by subtracting the incidence in the unexposed (Io) from the incidence in the total population (exposed and unexposed) [Ip].

What is the general population formula?

Population formula in economics is used to determine the economic activity of the country or area. Population percentage is the formula to divide the target demographic by the entire population, and then multiply the result by 100 to convert it to a percentage.

What is the difference between attributable risk and relative risk?

The value obtained by subtracting 1 from the relative risk is an excess relative risk and shows an increased amount of risks compared with a group free from risk factors. There is also an attributable risk that represents how much a certain factor increases the incidence or mortality rate of a group.

Is attributable risk a ratio?

Attributable risk (AR) is a measure of the proportion of the disease occurrence that can be attributed to a certain exposure. The risks among the exposed and unexposed groups are denoted p1 and p2. AR can then be expressed by estimating excess risk as p 1 − p 2 divided by the risk for the exposed group, p1, i.e., (9.9)

Is absolute and attributable risk the same?

Attributable risk measures the excess risk accounted for by exposure to a particular factor. 2 This is simply the difference between the absolute risks in the two groups. The term attributable risk is most commonly used in epidemiological studies.